This document discusses a computational fluid dynamics (CFD) analysis of a shell and tube heat exchanger with different baffle inclinations. The study aims to determine the optimal baffle inclination angle and mass flow rate. It analyzes heat transfer characteristics for baffle inclinations of 0, 10 and 20 degrees. The results indicate that a helical baffle configuration forces fluid rotation, increasing heat transfer rates and coefficients more than a segmental baffle design. Overall, the CFD simulation allows determination of outlet temperatures, pressure drops, and optimal design parameters for improved heat exchanger performance.
This document reviews various techniques for enhancing heat transfer through surfaces like tubes and ducts, specifically the use of ribs, fins, and inserts. It begins by classifying heat transfer enhancement techniques as active, passive, or compound. The majority of the document then focuses on passive techniques, including extended surfaces like fins and the use of inserts within ducts or tubes. It provides examples of different rib, fin, and insert configurations that have been used, and summarizes several studies that have experimentally analyzed heat transfer rates and pressure drops associated with these configurations under different parameters. Overall, the document serves as a literature review of using ribs, fins, and inserts to enhance heat transfer through surfaces in a passive manner without external power input.
Solar air heater (SAH), which is the most essential component of solar drying systems, receive solar energy and convert it into thermal energy. This review presents descriptions and previous works conducted on performances analysis of SAHs. Exergoenviroeconomic, exergoenvironmental, environmental, and exergy analyses are also presented. In addition, results on the performances of SAHs are summarized. The exergy and energy efficiencies of SAHs at laboratorium testing range from 8% to 61% and from 30% to 79%, respectively.
The document summarizes an exergy and exergo-economic analysis of the Montazer Ghaem gas turbine power plant in Iran. The analysis finds that the combustion chamber has the highest exergy destruction due to the large temperature difference between the flame and operating fluid. The gas turbine's performance and efficiency are significantly affected by ambient temperature. An increase in ambient temperature decreases the net power output and exergy efficiency. The exergo-economic analysis determines that the combustion chamber also has the largest cost of exergy destruction.
This document discusses steam turbine power plant design and cycles. It describes typical steam conditions between 600-1450 psig at 750-950°F for Army power plants. Back pressure turbines exhaust at 250-15 psig and condensing turbines exhaust at 1-5 inches of mercury absolute. Cogeneration plants use back pressure or controlled extraction/condensing cycles to simultaneously produce electric power and steam for heat. The document compares plant heat rates, turbine heat rates, and discusses optimizing steam power plant cycles for maximum efficiency and economy.
The document summarizes research on the suitability of heat exchangers for use as solar receivers in solar thermal power applications. It discusses two main solar collector technologies - point focusing and line focusing collectors - and the receiver design requirements for each. It then outlines the methodology used, which includes designing and fabricating a shell and helical tube heat exchanger, modeling a porous disc line receiver with CFD, simulating different configurations and working fluids, and determining parameters for maximum efficiency. Literature on existing receiver models is reviewed and key findings are summarized. Experimental work involving a shell and helical tube receiver with nanofluid is described and optimization of parameters is discussed. Results from CFD analysis of the porous disc receiver showing heat transfer and fluid
Comparative Study of ECONOMISER Using the CFD Analysis IJMER
This paper presents a simulation of the economizer zone, which allowsstudying the flow
patterns developed in the fluid, while it flows along the length of the economizer. The past failure
details revelsthat erosion is more in U-bend areas of Economizer Unit because of increase in flue gas
velocity near these bends. But it isobserved that the velocity of flue gases surprisingly increases near
the lower bends as compared to upper ones. The model issolved using conventional CFD techniques by
FLUENT software. In which the individual tubes are treated as sub-gridfeatures. A geometrical model
is used to describe the multiplicity of heat-exchanging structures and the interconnectionsamong them.
The Computational Fluid Dynamics (CFD) approach is utilised for the creation of a three-dimensional
modelof the economizer coil of single column tube. With equilibrium assumption applied for
description of the system chemistry. The flue gastemperature, pressure and velocity field of fluid flow
within an economizer tube using the actual bounda
The document presents information on helical baffle heat exchangers. It begins with introducing heat exchangers and defining a helical baffle heat exchanger. It then discusses the design of helixchangers, including thermal analysis of the helical baffles and tube side as well as hydrodynamic analysis of the shell side. Overall heat transfer coefficient is also examined. Key advantages of helixchangers are reduced bypass effects, fouling, vibration, and maintenance compared to traditional shell and tube exchangers. Future areas of research include CFD optimization and analysis of flow patterns and velocities.
ESTIMATION AND ANALYSIS OF CYCLE EFFICIENCY FOR SHELL AND TUBE HEAT EXCHANGER...IAEME Publication
Shell and tube Heat exchanger (STHE) is one of the most common and widely used energy transporter suited for domestic usages as well as industrial applications. In this paper, we consider shell and tube heat exchanger as a device with known input and output parameters. This work utilizes imperative design constraints like tube configuration, fluids, surface and temperature (constant magnitude) as input parameters and energetic cycle efficiency considered as desired output parameter depicting performance of the device. The model was trained and tested by proposed Genetic algorithm (GA) technique. This entire computational procedure is implemented in MATLAB platform.
This document reviews various techniques for enhancing heat transfer through surfaces like tubes and ducts, specifically the use of ribs, fins, and inserts. It begins by classifying heat transfer enhancement techniques as active, passive, or compound. The majority of the document then focuses on passive techniques, including extended surfaces like fins and the use of inserts within ducts or tubes. It provides examples of different rib, fin, and insert configurations that have been used, and summarizes several studies that have experimentally analyzed heat transfer rates and pressure drops associated with these configurations under different parameters. Overall, the document serves as a literature review of using ribs, fins, and inserts to enhance heat transfer through surfaces in a passive manner without external power input.
Solar air heater (SAH), which is the most essential component of solar drying systems, receive solar energy and convert it into thermal energy. This review presents descriptions and previous works conducted on performances analysis of SAHs. Exergoenviroeconomic, exergoenvironmental, environmental, and exergy analyses are also presented. In addition, results on the performances of SAHs are summarized. The exergy and energy efficiencies of SAHs at laboratorium testing range from 8% to 61% and from 30% to 79%, respectively.
The document summarizes an exergy and exergo-economic analysis of the Montazer Ghaem gas turbine power plant in Iran. The analysis finds that the combustion chamber has the highest exergy destruction due to the large temperature difference between the flame and operating fluid. The gas turbine's performance and efficiency are significantly affected by ambient temperature. An increase in ambient temperature decreases the net power output and exergy efficiency. The exergo-economic analysis determines that the combustion chamber also has the largest cost of exergy destruction.
This document discusses steam turbine power plant design and cycles. It describes typical steam conditions between 600-1450 psig at 750-950°F for Army power plants. Back pressure turbines exhaust at 250-15 psig and condensing turbines exhaust at 1-5 inches of mercury absolute. Cogeneration plants use back pressure or controlled extraction/condensing cycles to simultaneously produce electric power and steam for heat. The document compares plant heat rates, turbine heat rates, and discusses optimizing steam power plant cycles for maximum efficiency and economy.
The document summarizes research on the suitability of heat exchangers for use as solar receivers in solar thermal power applications. It discusses two main solar collector technologies - point focusing and line focusing collectors - and the receiver design requirements for each. It then outlines the methodology used, which includes designing and fabricating a shell and helical tube heat exchanger, modeling a porous disc line receiver with CFD, simulating different configurations and working fluids, and determining parameters for maximum efficiency. Literature on existing receiver models is reviewed and key findings are summarized. Experimental work involving a shell and helical tube receiver with nanofluid is described and optimization of parameters is discussed. Results from CFD analysis of the porous disc receiver showing heat transfer and fluid
Comparative Study of ECONOMISER Using the CFD Analysis IJMER
This paper presents a simulation of the economizer zone, which allowsstudying the flow
patterns developed in the fluid, while it flows along the length of the economizer. The past failure
details revelsthat erosion is more in U-bend areas of Economizer Unit because of increase in flue gas
velocity near these bends. But it isobserved that the velocity of flue gases surprisingly increases near
the lower bends as compared to upper ones. The model issolved using conventional CFD techniques by
FLUENT software. In which the individual tubes are treated as sub-gridfeatures. A geometrical model
is used to describe the multiplicity of heat-exchanging structures and the interconnectionsamong them.
The Computational Fluid Dynamics (CFD) approach is utilised for the creation of a three-dimensional
modelof the economizer coil of single column tube. With equilibrium assumption applied for
description of the system chemistry. The flue gastemperature, pressure and velocity field of fluid flow
within an economizer tube using the actual bounda
The document presents information on helical baffle heat exchangers. It begins with introducing heat exchangers and defining a helical baffle heat exchanger. It then discusses the design of helixchangers, including thermal analysis of the helical baffles and tube side as well as hydrodynamic analysis of the shell side. Overall heat transfer coefficient is also examined. Key advantages of helixchangers are reduced bypass effects, fouling, vibration, and maintenance compared to traditional shell and tube exchangers. Future areas of research include CFD optimization and analysis of flow patterns and velocities.
ESTIMATION AND ANALYSIS OF CYCLE EFFICIENCY FOR SHELL AND TUBE HEAT EXCHANGER...IAEME Publication
Shell and tube Heat exchanger (STHE) is one of the most common and widely used energy transporter suited for domestic usages as well as industrial applications. In this paper, we consider shell and tube heat exchanger as a device with known input and output parameters. This work utilizes imperative design constraints like tube configuration, fluids, surface and temperature (constant magnitude) as input parameters and energetic cycle efficiency considered as desired output parameter depicting performance of the device. The model was trained and tested by proposed Genetic algorithm (GA) technique. This entire computational procedure is implemented in MATLAB platform.
This document summarizes a research paper that analyzed heat transfer in an economizer using computational fluid dynamics (CFD). It discussed how fins can be added to economizer tubes to increase the heat transfer surface area between flue gases and boiler feedwater. The document reviewed previous research on economizer design optimization and failures. It described the working of CFD analysis using equations of continuity, momentum, and energy to model fluid flow. The study used the k-ε turbulence model in CFD software to analyze heat transfer with and without fins on an economizer.
Computational Fluid Dynamic Analysis for Optimization of Helical Coil Heat Ex...IRJET Journal
This document analyzes computational fluid dynamic (CFD) optimization of a helical coil heat exchanger. It compares CFD analysis results to experimental results and finds that decreasing the pitch length of the helical coil and relative velocity of fluids increases heat transfer rate. The document also describes an experimental setup used to study a helical coil heat exchanger and discusses previous research analyzing factors that affect heat transfer in helical coil exchangers, such as pitch length, tube diameter, and fluid velocity.
EXPERIMENTAL AND THEORTICAL STUDY OF THE THERMAL PERFORMANCE OF HEAT PIPE HEA...IAEME Publication
1. An experimental and theoretical study was conducted on a four row heat pipe heat exchanger with distilled water as the working fluid.
2. Tests were performed at varying air flow rates and inlet evaporator temperatures to analyze the effect on effectiveness.
3. The maximum effectiveness occurred at a mass flow rate ratio of 2. A theoretical model was developed and showed good agreement with experimental results.
Experimental Investigation of a Helical Coil Heat Exchangerinventy
The document summarizes an experimental study comparing the performance of a helical coil heat exchanger to a straight tube heat exchanger. Researchers designed, fabricated, and tested both types of heat exchangers. Results showed that the helical coil design had higher heat transfer rates, effectiveness, and overall heat transfer coefficients than the straight tube design across all flow rates and operating conditions. This is because the coiled tube shape induces secondary fluid flows that enhance mixing and heat transfer compared to the straight tube. The study concludes that helical coil heat exchangers have better performance than straight tube designs for industrial heat exchange applications.
This document discusses numerical simulation of a thermoacoustic engine (TAE). It begins by providing background on TAEs and previous simulation work. It then describes the methodology used, which involves CFD simulation of a standing wave TAE with a stack of horizontal plates as the regenerator. The study assesses pressure wave development and analyzes the sensitivity to temperature gradient at the stack and resonator length. Preliminary results show higher temperature gradients produce higher pressure amplitudes and earlier wave development, while medium resonator lengths provide both high amplitude and faster initiation compared to very short or long lengths.
Exergy analysis of inlet water temperature of condenserIJERA Editor
The most of the power plant designed by energetic performance criteria based on first law of thermodynamics. According to First law of thermodynamics energy analysis cannot be justified the losses of energy.The method of exergy analysis is well suited to describe true magnitude of waste and loss to be determined. Such information can be used in the design of new energy efficient system and increasing the efficiency of existing systems.In the present study exergy analysis of the shell and tube condenser is carried out. As the condenser is one of the major components of the power plant, so it is necessary to operate the condenser efficiently under the various operating condition to increase the overall efficiency of the power plant. In the present study inlet temperature of the condenser is optimized using the exergy method. The main aim of paper is to be find out causes of energy destruction that can be helpful to redesign the system and to increase the efficiency
Analysis of Coiled-Tube Heat Exchangers to Improve Heat Transfer Rate With Sp...IJMER
Steady heat transfer enhancement has been studied in helically coiled-tube heat exchangers. The outer side of the wall of the heat exchanger contains a helical corrugation which makes a helical rib on the inner side of the tube wall to induce additional swirling motion of fluid particles. Numerical calculations have been carried out to examine different geometrical parameters and the impact of flow and thermal boundary conditions for the heat transfer rate in laminar and transitional flow regimes. Calculated results have been compared to existing empirical formula and experimental tests to investigate the validity of the numerical results in case of common helical tube heat exchanger and additionally results of the numerical computation of corrugated straight tubes for laminar and transition flow have been validated with experimental tests available in the literature. Comparison of the flow and temperature fields in case of common helical tube and the coil with spirally corrugated wall configuration are discussed. Heat exchanger coils with helically corrugated wall configuration show 80–100% increase for the inner side heat transfer rate due to the additionally developed swirling motion while the relative pressure drop is 10–600% larger compared to the common helically coiled heat exchangers. New empirical Co-relation has been proposed for the fully developed inner side heat transfer prediction in case of helically corrugated wall configuration.
Heat exchangers are used widely in industrial application such as chemical,
food processing, power production, refrigeration and air-conditioning
industries. Helical coiled heat exchangers are used in order to obtain a large
heat transfer per unit volume and to enhance the heat transfer rate on the inside
surface. In the present study, CFD simulations are carried out for a counter
flow tube in tube helical heat exchanger where hot water flows through the
inner tube and cold water flows through the outer tube. From the simulation
results heat transfer coefficient, pressure drop and nusselt number are
calculated. The heat transfer characteristics of the same are compared with that
of a counter flow tube in tube straight tube heat exchanger of same length
under same temperature and flow conditions. CFD simulation results showed
that the helical tube in tube heat exchanger is more effective than the straight
tube in tube heat exchanger.
Helically Coiled Tube with Different Geometry and Curvature Ratio on Convecti...AM Publications
A helically coil-tube heat exchanger is generally applied in industry applications due to its compact structure, larger heat transfer area and higher heat transfer capability. Several studies from literature have also indicated that heat transfer rate in helically coiled tube are superior to straight tube due to complex flow pattern exist inside helical pipe. The concept behind compact heat exchanger is to decrease size and increase heat load which is the typical feature of modern helical tube heat exchanger. While the heat transfer characteristics of helical coil heat exchangers are available in the literature, This paper elaborates a brief review on different curvature ratio and geometry of tubes in heat transfer through heat exchangers.
This document summarizes a study that used computational fluid dynamics (CFD) to analyze heat transfer and flow characteristics in a solar air heater duct with ribbed surfaces. CFD simulations were performed for ducts with different rib configurations and Reynolds numbers. It was found that roughening the duct surface increased heat transfer but also increased friction losses. An optimal rib design was identified that provided maximum heat transfer enhancement with minimum pressure drop. Turbulence kinetic energy and intensity contours helped explain the increased turbulence near ribs that augmented heat transfer.
Paper design and optimizaton of steam distribution systems for steam power pl...Tony Lewis
This document presents a methodology for optimizing the design of steam distribution networks (SDNs) for steam power plants. The methodology formulates the problem as a mixed-integer nonlinear programming (MINLP) model to minimize total annualized cost. The model determines the optimal structure, configuration, and operation of the SDN as well as its interaction with the heat recovery system. Case studies are used to demonstrate the feasibility and benefits of the proposed simultaneous optimization approach.
Experimental Study of Heat Transfer Enhancement of Pipe-inPipe Helical Coil H...iosrjce
This document presents an experimental study of heat transfer enhancement in a pipe-in-pipe helical coil heat exchanger. Experiments were conducted with two different inner coil diameters (6mm and 8mm) under varying mass flow rates in the inner coil and annulus. The overall heat transfer coefficient and inner Nusselt number were found to increase with increasing mass flow rates. Counter-flow configuration resulted in higher heat transfer rates than parallel flow due to the larger log mean temperature difference, though overall heat transfer coefficients were similar between the two flow arrangements. Experimental results for inner Nusselt number agreed with established correlations in parallel flow but were higher in counter-flow.
This document presents a computational fluid dynamics (CFD) analysis of different heat sink shield profiles for electronic cooling. Three shield profiles - trapezoidal with curved inclination, trapezoidal with plane inclination, and slope shield - were modeled and simulated under a heat load of 75W. The trapezoidal shield with curved inclination achieved the lowest maximum temperature of 325.58K, highest heat transfer coefficient of 29.32, and highest surface Nusselt number of 1211.604, indicating it has the best thermal performance of the three profiles analyzed.
Comparative Study and Analysis between Helical Coil and Straight Tube Heat Ex...IJERA Editor
The purpose of this study is to determine the relative advantage of using a helically coiled heat exchanger against a straight tube heat exchanger. It is found that the heat transfer in helical circular tubes is higher as compared to Straight tube due to their shape. Helical coils offer advantageous over straight tubes due to their compactness and increased heat transfer coefficient. The increased heat transfer coefficients are a consequence of the curvature of the coil, which induces centrifugal forces to act on the moving fluid, resulting in the development of secondary flow. The curvature of the coil governs the centrifugal force while the pitch (or helix angle) influences the torsion to which the fluid is subjected to the centrifugal force results in the development of secondary flow. Due to the curvature effect, the fluid streams in the outer side of the pipe moves faster than the fluid streams in the inner side of the pipe. In current work the fluid to fluid heat exchange is taken into consideration. Most of the investigations on heat transfer coefficients are for constant wall temperature or constant heat flux. The effectiveness, overall heat transfer coefficient, effect of cold water flow rate on effectiveness of heat exchanger when hot water mass flow rate is kept constant and effect of hot water flow rate on effectiveness when cold water flow rate kept constant studied and compared for parallel flow, counter flow arrangement of Helical coil and Straight tube heat exchangers. All readings were taken at steady state condition of heat exchanger. The result shows that the heat transfer coefficient is affected by the geometry of the heat exchanger. Helical coil heat exchanger are superior in all aspect studied here.
This document discusses a numerical analysis of natural convection cooling of electronic components mounted on an aluminum plate within the walls of a train. The study examines the effect of a discontinuous heat flux distribution from the components on heat transfer. The results show that the heat flux distribution significantly influences cooling efficiency. Optimizing the placement and sizing of components can maximize heat transfer and minimize temperatures for improved cooling of power converters inside trains.
IRJET-Study of Space Cooling System Consisting of Aluminium Ammonia Heat Pipe...IRJET Journal
This document summarizes a study on an active space cooling system consisting of an aluminum-ammonia heat pipe and a variable emittance radiator with micro-electro-mechanical systems (MEMS) louvers. The system uses a loop heat pipe to transfer heat from an evaporator to a condenser, where a variable emittance radiator rejects heat to space. A fuzzy logic controller adapts the radiator's emittance by adjusting the number of open MEMS louvers. Simulation results show the controller improves thermal control and ensures safe operation of the heat pipe cooling system.
45
50
55
60
65
Pr (ata)
Graph 3. Variation of power and efficiency with pressure at temperature at 4500C
This document summarizes the results of a sensitivity analysis performed on a heat recovery steam generator (HRSG) for a GE 6FA gas turbine combined cycle power plant. The analysis varied the steam pressure from 40 to 62 atmospheres and steam temperature from 400 to 500 degrees Celsius to determine the optimal operating point. The maximum power and efficiency were achieved at different pressure-temperature combinations, with 58 atmospheres generally providing the best results for temperatures between 450-500 degrees Celsius. Graphs show the relationships between pressure, power, efficiency
This document summarizes research on topology control techniques in wireless sensor networks. It first discusses how topology control aims to reduce energy consumption while maintaining network connectivity by regulating nodes' transmission power. It then reviews several existing topology control algorithms proposed in other papers. These algorithms distribute transmission power control to maximize network lifetime. Finally, the document concludes that many topology control algorithms have been developed to achieve energy efficient routing, but implementing them on real-world testbeds poses challenges.
This document describes the simulation of a requester device using VHDL to enable Ethernet communication. The requester device is designed to transmit and receive data through GPIO ports to allow connection to external devices. It consists of GPIO to FIFO and FIFO to GPIO blocks to transfer data between the ports and FIFO memory. The device is simulated using ModelSim software. The simulation demonstrates the forwarding of data from GPIO input to output through the FIFO blocks, showing it can function as a mediator for data transfer required for Ethernet communication platforms.
This document discusses improving data security for mobile devices using cloud computing storage. It proposes encrypting data stored in the cloud to address security issues. Mobile cloud computing integrates mobile networks and cloud computing to provide services for mobile users. However, storing large amounts of personal and enterprise data in the cloud raises security risks regarding data integrity, authentication, and access. The document reviews these risks and considers solutions like encryption and digital rights management to protect data stored in the cloud.
This document summarizes the design optimization and analysis of an impeller for a centrifugal compressor. It begins with background on centrifugal compressors and their applications. The aim is then stated as developing a methodology to design a centrifugal compressor impeller accounting for real fluid effects. A computer program is developed based on jet-wake theory to estimate impeller dimensions. The methodology is validated by comparing results to an existing impeller design, showing encouraging accuracy. The method is then applied to design an impeller for an air conditioning system using R-12 as the refrigerant at 18,000 rpm. Key design parameters are examined at varying speeds to select optimal values.
This document presents a performance analysis of an XML to HTML converter. It describes creating a converter that takes XML files with predefined tags as input and generates equivalent HTML files. This is done to reduce the response time of web pages compared to using ASP.NET server controls, which have a large lifecycle. Two test websites were created, one with the converter and one with ASP.NET controls, and response time graphs and aggregate graphs from testing show that the website using the XML converter performed much better with lower response times.
This document summarizes a research paper that analyzed heat transfer in an economizer using computational fluid dynamics (CFD). It discussed how fins can be added to economizer tubes to increase the heat transfer surface area between flue gases and boiler feedwater. The document reviewed previous research on economizer design optimization and failures. It described the working of CFD analysis using equations of continuity, momentum, and energy to model fluid flow. The study used the k-ε turbulence model in CFD software to analyze heat transfer with and without fins on an economizer.
Computational Fluid Dynamic Analysis for Optimization of Helical Coil Heat Ex...IRJET Journal
This document analyzes computational fluid dynamic (CFD) optimization of a helical coil heat exchanger. It compares CFD analysis results to experimental results and finds that decreasing the pitch length of the helical coil and relative velocity of fluids increases heat transfer rate. The document also describes an experimental setup used to study a helical coil heat exchanger and discusses previous research analyzing factors that affect heat transfer in helical coil exchangers, such as pitch length, tube diameter, and fluid velocity.
EXPERIMENTAL AND THEORTICAL STUDY OF THE THERMAL PERFORMANCE OF HEAT PIPE HEA...IAEME Publication
1. An experimental and theoretical study was conducted on a four row heat pipe heat exchanger with distilled water as the working fluid.
2. Tests were performed at varying air flow rates and inlet evaporator temperatures to analyze the effect on effectiveness.
3. The maximum effectiveness occurred at a mass flow rate ratio of 2. A theoretical model was developed and showed good agreement with experimental results.
Experimental Investigation of a Helical Coil Heat Exchangerinventy
The document summarizes an experimental study comparing the performance of a helical coil heat exchanger to a straight tube heat exchanger. Researchers designed, fabricated, and tested both types of heat exchangers. Results showed that the helical coil design had higher heat transfer rates, effectiveness, and overall heat transfer coefficients than the straight tube design across all flow rates and operating conditions. This is because the coiled tube shape induces secondary fluid flows that enhance mixing and heat transfer compared to the straight tube. The study concludes that helical coil heat exchangers have better performance than straight tube designs for industrial heat exchange applications.
This document discusses numerical simulation of a thermoacoustic engine (TAE). It begins by providing background on TAEs and previous simulation work. It then describes the methodology used, which involves CFD simulation of a standing wave TAE with a stack of horizontal plates as the regenerator. The study assesses pressure wave development and analyzes the sensitivity to temperature gradient at the stack and resonator length. Preliminary results show higher temperature gradients produce higher pressure amplitudes and earlier wave development, while medium resonator lengths provide both high amplitude and faster initiation compared to very short or long lengths.
Exergy analysis of inlet water temperature of condenserIJERA Editor
The most of the power plant designed by energetic performance criteria based on first law of thermodynamics. According to First law of thermodynamics energy analysis cannot be justified the losses of energy.The method of exergy analysis is well suited to describe true magnitude of waste and loss to be determined. Such information can be used in the design of new energy efficient system and increasing the efficiency of existing systems.In the present study exergy analysis of the shell and tube condenser is carried out. As the condenser is one of the major components of the power plant, so it is necessary to operate the condenser efficiently under the various operating condition to increase the overall efficiency of the power plant. In the present study inlet temperature of the condenser is optimized using the exergy method. The main aim of paper is to be find out causes of energy destruction that can be helpful to redesign the system and to increase the efficiency
Analysis of Coiled-Tube Heat Exchangers to Improve Heat Transfer Rate With Sp...IJMER
Steady heat transfer enhancement has been studied in helically coiled-tube heat exchangers. The outer side of the wall of the heat exchanger contains a helical corrugation which makes a helical rib on the inner side of the tube wall to induce additional swirling motion of fluid particles. Numerical calculations have been carried out to examine different geometrical parameters and the impact of flow and thermal boundary conditions for the heat transfer rate in laminar and transitional flow regimes. Calculated results have been compared to existing empirical formula and experimental tests to investigate the validity of the numerical results in case of common helical tube heat exchanger and additionally results of the numerical computation of corrugated straight tubes for laminar and transition flow have been validated with experimental tests available in the literature. Comparison of the flow and temperature fields in case of common helical tube and the coil with spirally corrugated wall configuration are discussed. Heat exchanger coils with helically corrugated wall configuration show 80–100% increase for the inner side heat transfer rate due to the additionally developed swirling motion while the relative pressure drop is 10–600% larger compared to the common helically coiled heat exchangers. New empirical Co-relation has been proposed for the fully developed inner side heat transfer prediction in case of helically corrugated wall configuration.
Heat exchangers are used widely in industrial application such as chemical,
food processing, power production, refrigeration and air-conditioning
industries. Helical coiled heat exchangers are used in order to obtain a large
heat transfer per unit volume and to enhance the heat transfer rate on the inside
surface. In the present study, CFD simulations are carried out for a counter
flow tube in tube helical heat exchanger where hot water flows through the
inner tube and cold water flows through the outer tube. From the simulation
results heat transfer coefficient, pressure drop and nusselt number are
calculated. The heat transfer characteristics of the same are compared with that
of a counter flow tube in tube straight tube heat exchanger of same length
under same temperature and flow conditions. CFD simulation results showed
that the helical tube in tube heat exchanger is more effective than the straight
tube in tube heat exchanger.
Helically Coiled Tube with Different Geometry and Curvature Ratio on Convecti...AM Publications
A helically coil-tube heat exchanger is generally applied in industry applications due to its compact structure, larger heat transfer area and higher heat transfer capability. Several studies from literature have also indicated that heat transfer rate in helically coiled tube are superior to straight tube due to complex flow pattern exist inside helical pipe. The concept behind compact heat exchanger is to decrease size and increase heat load which is the typical feature of modern helical tube heat exchanger. While the heat transfer characteristics of helical coil heat exchangers are available in the literature, This paper elaborates a brief review on different curvature ratio and geometry of tubes in heat transfer through heat exchangers.
This document summarizes a study that used computational fluid dynamics (CFD) to analyze heat transfer and flow characteristics in a solar air heater duct with ribbed surfaces. CFD simulations were performed for ducts with different rib configurations and Reynolds numbers. It was found that roughening the duct surface increased heat transfer but also increased friction losses. An optimal rib design was identified that provided maximum heat transfer enhancement with minimum pressure drop. Turbulence kinetic energy and intensity contours helped explain the increased turbulence near ribs that augmented heat transfer.
Paper design and optimizaton of steam distribution systems for steam power pl...Tony Lewis
This document presents a methodology for optimizing the design of steam distribution networks (SDNs) for steam power plants. The methodology formulates the problem as a mixed-integer nonlinear programming (MINLP) model to minimize total annualized cost. The model determines the optimal structure, configuration, and operation of the SDN as well as its interaction with the heat recovery system. Case studies are used to demonstrate the feasibility and benefits of the proposed simultaneous optimization approach.
Experimental Study of Heat Transfer Enhancement of Pipe-inPipe Helical Coil H...iosrjce
This document presents an experimental study of heat transfer enhancement in a pipe-in-pipe helical coil heat exchanger. Experiments were conducted with two different inner coil diameters (6mm and 8mm) under varying mass flow rates in the inner coil and annulus. The overall heat transfer coefficient and inner Nusselt number were found to increase with increasing mass flow rates. Counter-flow configuration resulted in higher heat transfer rates than parallel flow due to the larger log mean temperature difference, though overall heat transfer coefficients were similar between the two flow arrangements. Experimental results for inner Nusselt number agreed with established correlations in parallel flow but were higher in counter-flow.
This document presents a computational fluid dynamics (CFD) analysis of different heat sink shield profiles for electronic cooling. Three shield profiles - trapezoidal with curved inclination, trapezoidal with plane inclination, and slope shield - were modeled and simulated under a heat load of 75W. The trapezoidal shield with curved inclination achieved the lowest maximum temperature of 325.58K, highest heat transfer coefficient of 29.32, and highest surface Nusselt number of 1211.604, indicating it has the best thermal performance of the three profiles analyzed.
Comparative Study and Analysis between Helical Coil and Straight Tube Heat Ex...IJERA Editor
The purpose of this study is to determine the relative advantage of using a helically coiled heat exchanger against a straight tube heat exchanger. It is found that the heat transfer in helical circular tubes is higher as compared to Straight tube due to their shape. Helical coils offer advantageous over straight tubes due to their compactness and increased heat transfer coefficient. The increased heat transfer coefficients are a consequence of the curvature of the coil, which induces centrifugal forces to act on the moving fluid, resulting in the development of secondary flow. The curvature of the coil governs the centrifugal force while the pitch (or helix angle) influences the torsion to which the fluid is subjected to the centrifugal force results in the development of secondary flow. Due to the curvature effect, the fluid streams in the outer side of the pipe moves faster than the fluid streams in the inner side of the pipe. In current work the fluid to fluid heat exchange is taken into consideration. Most of the investigations on heat transfer coefficients are for constant wall temperature or constant heat flux. The effectiveness, overall heat transfer coefficient, effect of cold water flow rate on effectiveness of heat exchanger when hot water mass flow rate is kept constant and effect of hot water flow rate on effectiveness when cold water flow rate kept constant studied and compared for parallel flow, counter flow arrangement of Helical coil and Straight tube heat exchangers. All readings were taken at steady state condition of heat exchanger. The result shows that the heat transfer coefficient is affected by the geometry of the heat exchanger. Helical coil heat exchanger are superior in all aspect studied here.
This document discusses a numerical analysis of natural convection cooling of electronic components mounted on an aluminum plate within the walls of a train. The study examines the effect of a discontinuous heat flux distribution from the components on heat transfer. The results show that the heat flux distribution significantly influences cooling efficiency. Optimizing the placement and sizing of components can maximize heat transfer and minimize temperatures for improved cooling of power converters inside trains.
IRJET-Study of Space Cooling System Consisting of Aluminium Ammonia Heat Pipe...IRJET Journal
This document summarizes a study on an active space cooling system consisting of an aluminum-ammonia heat pipe and a variable emittance radiator with micro-electro-mechanical systems (MEMS) louvers. The system uses a loop heat pipe to transfer heat from an evaporator to a condenser, where a variable emittance radiator rejects heat to space. A fuzzy logic controller adapts the radiator's emittance by adjusting the number of open MEMS louvers. Simulation results show the controller improves thermal control and ensures safe operation of the heat pipe cooling system.
45
50
55
60
65
Pr (ata)
Graph 3. Variation of power and efficiency with pressure at temperature at 4500C
This document summarizes the results of a sensitivity analysis performed on a heat recovery steam generator (HRSG) for a GE 6FA gas turbine combined cycle power plant. The analysis varied the steam pressure from 40 to 62 atmospheres and steam temperature from 400 to 500 degrees Celsius to determine the optimal operating point. The maximum power and efficiency were achieved at different pressure-temperature combinations, with 58 atmospheres generally providing the best results for temperatures between 450-500 degrees Celsius. Graphs show the relationships between pressure, power, efficiency
This document summarizes research on topology control techniques in wireless sensor networks. It first discusses how topology control aims to reduce energy consumption while maintaining network connectivity by regulating nodes' transmission power. It then reviews several existing topology control algorithms proposed in other papers. These algorithms distribute transmission power control to maximize network lifetime. Finally, the document concludes that many topology control algorithms have been developed to achieve energy efficient routing, but implementing them on real-world testbeds poses challenges.
This document describes the simulation of a requester device using VHDL to enable Ethernet communication. The requester device is designed to transmit and receive data through GPIO ports to allow connection to external devices. It consists of GPIO to FIFO and FIFO to GPIO blocks to transfer data between the ports and FIFO memory. The device is simulated using ModelSim software. The simulation demonstrates the forwarding of data from GPIO input to output through the FIFO blocks, showing it can function as a mediator for data transfer required for Ethernet communication platforms.
This document discusses improving data security for mobile devices using cloud computing storage. It proposes encrypting data stored in the cloud to address security issues. Mobile cloud computing integrates mobile networks and cloud computing to provide services for mobile users. However, storing large amounts of personal and enterprise data in the cloud raises security risks regarding data integrity, authentication, and access. The document reviews these risks and considers solutions like encryption and digital rights management to protect data stored in the cloud.
This document summarizes the design optimization and analysis of an impeller for a centrifugal compressor. It begins with background on centrifugal compressors and their applications. The aim is then stated as developing a methodology to design a centrifugal compressor impeller accounting for real fluid effects. A computer program is developed based on jet-wake theory to estimate impeller dimensions. The methodology is validated by comparing results to an existing impeller design, showing encouraging accuracy. The method is then applied to design an impeller for an air conditioning system using R-12 as the refrigerant at 18,000 rpm. Key design parameters are examined at varying speeds to select optimal values.
This document presents a performance analysis of an XML to HTML converter. It describes creating a converter that takes XML files with predefined tags as input and generates equivalent HTML files. This is done to reduce the response time of web pages compared to using ASP.NET server controls, which have a large lifecycle. Two test websites were created, one with the converter and one with ASP.NET controls, and response time graphs and aggregate graphs from testing show that the website using the XML converter performed much better with lower response times.
This document summarizes a research paper that proposes a hybrid evolutionary clustering approach for optimized routing in mobile ad hoc networks. It uses particle swarm optimization (PSO) and ant colony optimization (ACO) to perform spatial clustering of nodes. Greedy routing is then used to find routes, and when dead ends are encountered, genetic algorithms are applied to find alternative routes. The approach aims to improve greedy routing performance and recovery from dead ends by avoiding the use of floating nodes. Simulation results showed improved greedy routing and fewer concave nodes compared to other methods.
The document compares the design of circular and square water tanks using the working stress method and limit state method. It was found that:
1) The limit state method requires less steel than the working stress method for both circular and square tank designs.
2) A circular tank design is more economical than a square tank design due to requiring less steel.
3) The limit state method results in a more rational and economical design compared to the traditional working stress method.
This document summarizes a study that used casting simulation software to model and optimize the sand casting process for a steel flywheel. The researchers first modeled the flywheel component along with gating and risering systems. Simulation of the initial model revealed shrinkage defects. The model was modified by changing the ingate locations and adding risers, which directionally solidified the casting. The modified model was then simulated using ADSTEFAN software to analyze fluid flow, solidification patterns, and potential defects like shrinkage and porosity. The simulation results helped optimize the casting design to improve quality and yield.
This document summarizes a study on a biomethanation plant that converts vegetable waste into biogas. Some key points:
- The plant uses a BIMA digester to break down vegetable waste from markets into biogas through anaerobic digestion.
- The process involves shredding the waste, digestion in the BIMA digester to produce biogas, collection of biogas, power generation from the biogas, dewatering of the digested substrate, and odor control.
- The byproduct of digestion (biodigested slurry) is a valuable organic manure high in nutrients that can be used to enrich soils or as fertilizer.
This document discusses India's smart cities initiative and the role of public-private partnerships. It notes that India's urban population is growing rapidly and current infrastructure cannot support this growth. The government plans to build 100 smart cities to address issues like pollution, congestion, and resource scarcity. Public-private partnerships are seen as key to providing the large investments needed, estimated at over $10 billion per city. PPPs can help develop smart infrastructure, healthcare, mobility, technology and energy systems. The document analyzes how PPPs can ensure quality infrastructure and services to enable smart city development in India.
This document summarizes a study on the foreign exchange exposure of Indian corporate firms from 2009 to 2013. The study estimated foreign exchange exposure using ordinary least squares regression with various trade-weighted exchange rate indices. Key findings include:
1) Foreign exchange exposure was estimated for a sample of 27 non-financial Indian firms using different exchange rate indices.
2) Exposure was measured as the sensitivity of stock returns to changes in exchange rates based on the model developed by Adler and Dumas.
3) Preliminary results found Indian firms may benefit from appreciation of the home currency and lose from depreciation, but overall exposure was weakly significant.
This document analyzes the performance of a diesel engine fueled with blends of biodiesel derived from Cashew Nut Shell Liquid (CNSL) and ethanol. Experiments were conducted with diesel and blends containing 10%, 15%, 20% CNSL, as well as blends with 5% and 10% ethanol added to the 15% CNSL blend. Performance parameters like brake thermal efficiency, fuel consumption, emissions were measured and compared across fuel blends and to diesel. Results showed the 15% CNSL blend performed better than other blends, while adding ethanol reduced performance due to its lower energy content. This research evaluates CNSL biodiesel and its blends as potential alternatives to conventional diesel
1. ICT (information and communication technologies) have transformed education by facilitating access to information, communication, and new modes of learning. The internet and mobile technologies have expanded opportunities for online, blended, and mobile learning.
2. Students now need digital literacy skills to effectively search, evaluate, and utilize the vast amount of online information. Key 21st century skills identified include digital literacy, inventive thinking, effective communication, and high productivity.
3. ICT have impacted teaching by shifting teachers' roles from knowledge transmitters to learning facilitators. They have also changed student roles from passive recipients to active participants in collaborative learning. Technologies like interactive whiteboards enhance interactive learning.
This document summarizes a proposed architecture for remote patient monitoring using wireless sensor networks. The architecture allows virtual groups to be formed between patients, nurses, and doctors to enable remote analysis of patient data collected by wireless body area networks (WBANs). The patient data is transmitted through an underlying environmental sensor network to members of the virtual group. The proposed architecture addresses challenges of power supply for body sensor networks and quality of service guarantees.
1. The document presents a new approach for steganography detection using a combination of Fisher's linear discriminant function (FLD) and radial basis function neural network (RBF).
2. In the training phase, FLD is used to project high-dimensional image data onto a lower dimensional space, then an RBF network is trained to classify images as containing hidden data or not.
3. Experiments show the combined FLD-RBF method provides promising results for steganography detection compared to existing supervised methods, though extracting the hidden information remains challenging.
This document describes how to hack into a target machine using social engineering and SSH. It involves using Nmap to scan the target machine and find open ports, then using Hydra to brute force common username and password combinations to gain SSH access. Once logged in via SSH, the hacker can explore the system but does not have root privileges. The document provides steps to gain root access including viewing the /etc/passwd file to find the root username and attempt to su to gain root privileges on the target machine.
This document summarizes research on utilizing fly ash to treat domestic wastewater. Fly ash was collected and characterized, then used as a filter media in two containers with thicknesses of 5 cm and 10 cm. Domestic wastewater was treated by passing it through the fly ash filters. Testing showed the 10 cm thick fly ash filter reduced biochemical oxygen demand by 71.48%, chemical oxygen demand by 66.59%, and total solids by 69.02% compared to untreated wastewater. The research concludes that fly ash is effective at removing various impurities from domestic wastewater and is a low-cost option for small-scale wastewater treatment.
The document discusses using support vector machines (SVM) and various lexical, semantic, and syntactic features for question classification. It aims to develop a state-of-the-art machine learning based question classifier. Various features are discussed, including lexical features like n-grams and stemming, syntactic features like question headwords, and semantic features derived from named entity recognition, WordNet senses, and semantic word lists. SVM is used as the classifier to take advantage of its good performance for text classification tasks. The results show that combining these feature types can achieve accurate question classification.
This document describes the design and implementation of a printed monopole antenna for use in the 2.4-2.4835 GHz Industrial Scientific and Medical (ISM) band. It begins with an introduction to wireless communications in the ISM band and the challenges of developing small, low-cost integrated antennas for these applications. It then outlines the methodology for antenna design which includes calculating dimensions, simulation, observation, and hardware implementation. The design specification and steps taken to design the rectangular microstrip patch antenna are provided, including choosing parameters like resonant frequency, dielectric material, and substrate height. Simulation results for parameters like radiation pattern and bandwidth are analyzed. The document concludes that printed monopole antennas are well-suited for ISM band applications
This document discusses the use of an adaptive decision feedback equalizer (ADFE) to mitigate pulse dispersion in optical communication channels. It begins by describing different sources of dispersion in optical fibers. Then it proposes using a fractional spaced decision feedback equalizer (FSDFE) integrated with activity detection guidance (ADG) and tap decoupling (TD) to improve performance. Simulation results show the FSDFE can estimate the channel impulse response and minimize differences between the input and output. Adding ADG and TD further improves convergence rate, detection of inactive taps, and asymptotic performance. The ADFE is an effective technique for equalization and mitigating dispersion in optical links.
IRJET- Modelling and CFD Simulation of Prototype of AC Plant Chiller On-Board...IRJET Journal
This document summarizes a study that models and simulates a shell and tube heat exchanger used in marine ship air conditioning plants. The study involves:
1. Modeling the geometry of a prototype shell and tube heat exchanger in Solidworks based on design calculations.
2. Meshing the model in ICEM CFD and applying boundary conditions representing different mass flow rates to simulate heat transfer.
3. Using ANSYS Fluent CFD software to analyze temperature distribution and flow patterns within the shell and tubes at 100% and 75% loading.
4. Comparing CFD results to experimental temperature data from factory acceptance trials to validate the simulation model.
The goal is to model the
Comparison of Shell and Tube Heat Exchanger using Theoretical Methods, HTRI, ...IJERA Editor
This document compares the design of a shell and tube heat exchanger with baffles using four different methods: 1) Kern's theoretical method, 2) ASPEN simulation software, 3) HTRI simulation software, and 4) SOLIDWORKS simulation software. The same input parameters were used to design a shell and tube heat exchanger with single segmental baffles in each method. The results from all four methods for shell side pressure drop and heat transfer coefficient were found to be in close agreement. The theoretical Kern method design results closely matched the simulation software results, showing proven theoretical methods can accurately model shell and tube heat exchanger performance.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document provides an overview of the functional design of two types of heat exchangers: shell and tube heat exchangers and plate heat exchangers. It discusses the key components, design considerations, and step-by-step design procedures for shell and tube heat exchangers. These include determining the heat transfer area, number of tubes, tube dimensions, baffle design, and accounting for pressure drops and fouling factors. It also introduces plate heat exchangers and discusses their mechanical characteristics and design methods at a high level.
IRJET- Design and Computational Analysis of Shell and Tube Heat Exchanger Con...IRJET Journal
This document describes a computational fluid dynamics (CFD) analysis of a shell and tube heat exchanger considering various parameters. The analysis models and simulates the geometry of a shell and tube heat exchanger using ANSYS to study the temperature and pressure fields inside the shell. Variables analyzed include mass flow rate, baffle inclination angle, outlet temperature, and pressure drop. The results show increased heat exchanger performance with a helical baffle design compared to a conventional segmental baffle design.
iaetsd Heat transfer enhancement of shell and tube heat exchanger using conic...Iaetsd Iaetsd
This document discusses heat transfer enhancement in a shell and tube heat exchanger using a conical tape insert. It provides heat transfer and friction factor data from experiments using the heat exchanger fitted with a helical tape insert. Hot air was passed through the inner tube while cold water flowed in the annulus. The helical insert increased heat transfer rate by up to 165% compared to the plain tube, with some increase in pressure drop. Equations and calculations are provided for determining heat transfer coefficients, pressure drops, and other parameters on both the shell and tube sides of the heat exchanger. Graphs of results are also presented.
Heat Transfer Enhancement of Shell and Tube Heat Exchanger Using Conical Tapes.IJERA Editor
This paper provides heat transfer and friction factor data for single -phase flow in a shell and tube heat exchanger fitted with a helical tape insert. In the double concentric tube heat exchanger, hot air was passed through the inner tube while the cold water was flowed through the annulus. The influences of the helical insert on heat transfer rate and friction factor were studied for counter flow, and Nusselt numbers and friction factor obtained were compared with previous data (Dittus 1930, Petukhov 1970, Moody 1944) for axial flows in the plain tube. The flow considered is in a low Reynolds number range between 2300 and 8800. A maximum percentage gain of 165% in heat transfer rate is obtained for using the helical insert in comparison with the plain tube.
ONGC Training on Heat Exchangers, Compressors & PumpsAkansha Jha
Plant overview, working of compressors, pumps, cooling towers, gas turbines.
Mini- Project on shell & tube type heat exchangers in ONGC, Uran plant. Hence,
calculating the effectiveness of heat exchanger using the working data.
Design and Analysis of Heat Exchanger for Maximum Heat Transfer Rate (Multi M...IRJET Journal
This document summarizes a study on optimizing the design of a shell and tube heat exchanger to maximize heat transfer rate. The researchers designed a shell and tube heat exchanger using standard TEMA specifications. They then analyzed different tube designs, baffle inclinations, and coolant fluids using computational fluid dynamics simulations. The optimum design was found to be a tube with both angled and stepped sections, baffles inclined at 35 degrees, and a coolant of copper oxide nanoparticles in water. This design achieved a temperature drop of 48.6 degrees Celsius between the hot and cold fluids.
FEEMSSD presentation on shell and tube heat exchanger75 .pptxAdarshPandey510683
The document describes the design of a shell and tube heat exchanger. It discusses the components of a shell and tube heat exchanger including the shell, tubes, tube bundle, tubesheet, expansion joint, flanges, gaskets, nozzles, and baffles. It also outlines the objectives of designing a shell and tube heat exchanger for an industry application. The thermal design process involves selecting fluids for the tube and shell sides based on properties, calculating the heat transfer area, tube dimensions, and other parameters. The results of the design case study showed that using recommended design ranges from literature led to an optimal design that met design specifications.
Type of heat exchanger. Which is mainly used in food industries, like dairy plant, for the pasturization, heat treatment of the beavrages or liquid raw material.
Analysis of Heat Transfer in Spiral Plate Heat Exchanger Using Experimental a...ijsrd.com
Heat transfer is the key to several processes in industrial application. In a present days maximum efficient heat transfer equipment are in demand due to increasing energy cost. For achieving maximum heat transfer, the engineers are continuously upgrading their knowledge and skills by their past experience. Present work is a skip in the direction of demonstrating the use of the computational technique as a tool to substitute experimental techniques. For this purpose an experimental set up has been designed and developed. Analysis of heat transfer in spiral plate heat exchanger is performed and same Analysis of heat transfer in spiral plate heat exchanger can be done by commercially procurable computational fluid dynamic (CFD) using ANSYS CFX and validated based on this forecasting. Analysis has been carried out in parallel and counter flow with inward and outward direction for achieving maximum possible heat transfer. In this problem of heat transfer involved the condition where Reynolds number again and again varies as the fluid traverses inside the section of flow from inlet to exit, mass flow rate of working fluid is been modified with time. By more and more analysis and experimentation and systematic data degradation leads to the conclusion that the maximum heat transfer rates is obtained in case of the inward parallel flow configuration compared to all other counterparts, which observed to vary with small difference in each section. Furthermore, for the increase heat transfer rate in spiral plate heat exchanger is obtain by cascading system.
IRJET- A Review on Basics of Heat ExchangerIRJET Journal
This document reviews the basics of heat exchangers. It discusses that heat exchangers are used to transfer heat between two or more fluids for heating and cooling processes. The three main types of heat exchangers are shell and tube, plate, and double pipe heat exchangers. It also discusses computational fluid dynamics as a method to analyze fluid flow and heat transfer in heat exchangers numerically. The document then reviews the basic design methods for two fluid heat exchangers, including the log-mean temperature difference method, effectiveness-NTU method, and other graphical methods.
A tube heat exchanger consists of a shell containing a bundle of tubes, with one fluid flowing through the tubes and another fluid flowing over the tubes to facilitate heat transfer. There are several types of heat exchangers that vary in their design and construction, but all aim to efficiently transfer heat from one fluid to another.
IRJET- Analysis of Shell and Tube Heat ExchangersIRJET Journal
The document analyzes the design and performance of shell and tube heat exchangers. It discusses the components of shell and tube heat exchangers including tubes, tube sheets, baffles, and nozzles. It also describes three common types of shell and tube exchangers: fixed tube sheet, U-tube, and floating head. The document then analyzes the performance of a shell and tube heat exchanger model made of brass with and without baffles using structural and thermal simulations. The results show that heat transfer rate and stresses are lower for the model with baffles compared to without baffles. Brass is also found to have lower stresses than other materials like carbon steel and stainless steel.
REDESIGN OF SHELL AND TUBE HEAT EXCHANGER 1Sanju Jacob
The document discusses redesigning a shell and tube heat exchanger to increase its effectiveness. It analyzes increasing the number of tubes from 184 to 234. This results in the effectiveness increasing from 5.77 to 8.80, an improvement of 34.4%. Key components of shell and tube heat exchangers like shells, tubes, and baffles are also outlined. The redesign aims to accommodate a 65% increase in thermal load for a chemical process.
Analysis of Double Pipe Heat Exchanger With Helical FinsIRJET Journal
This document analyzes a double pipe heat exchanger with helical fins through computational fluid dynamics (CFD). It aims to study the flow and temperature fields inside the tubes for different helical fin angles. The geometry of the double pipe heat exchanger is modeled in CATIA V5 and meshed in Hypermesh. CFD simulations are performed in ANSYS Fluent to analyze the flow and temperature distributions for fin angles of 0, 5, 10, 15, 20, and 25 degrees. The results determine that heat transfer rate and overall heat transfer coefficient increase with helical fins compared to a smooth tube, with fins providing additional surface area to enhance heat transfer.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document discusses the basics of shell-and-tube heat exchanger (STHE) thermal design. It covers key topics such as STHE components, classification based on construction and service, data needed for design, tubeside design, shellside design including baffling and pressure drop, and mean temperature difference. The focus is on applying basic heat transfer and pressure drop equations to optimize STHE design.
This document summarizes a research paper that examines pricing strategy in a two-stage supply chain consisting of a supplier and retailer. The supplier offers a credit period to the retailer, who then offers credit to customers. A mathematical model is formulated to maximize total profit for the integrated supply chain system. The model considers three cases based on the relative lengths of the credit periods offered at each stage. Equations are developed to represent the profit functions for the supplier, retailer and overall system in each case. The goal is to determine the optimal selling price that maximizes total integrated profit.
The document discusses melanoma skin cancer detection using a computer-aided diagnosis system based on dermoscopic images. It begins with an introduction to skin cancer and melanoma. It then reviews existing literature on automated melanoma detection systems that use techniques like image preprocessing, segmentation, feature extraction and classification. Features extracted in other studies include asymmetry, border irregularity, color, diameter and texture-based features. The proposed system collects dermoscopic images and performs preprocessing, segmentation, extracts 9 features based on the ABCD rule, and classifies images using a neural network classifier to detect melanoma. It aims to develop an automated diagnosis system to eliminate invasive biopsy procedures.
This document summarizes various techniques for image segmentation that have been studied and proposed in previous research. It discusses edge-based, threshold-based, region-based, clustering-based, and other common segmentation methods. It also reviews applications of segmentation in medical imaging, plant disease detection, and other fields. While no single technique can segment all images perfectly, hybrid and adaptive methods combining multiple approaches may provide better results. Overall, image segmentation remains an important but challenging task in digital image processing and computer vision.
This document presents a test for detecting a single upper outlier in a sample from a Johnson SB distribution when the parameters of the distribution are unknown. The test statistic proposed is based on maximum likelihood estimates of the four parameters (location, scale, and two shape) of the Johnson SB distribution. Critical values of the test statistic are obtained through simulation for different sample sizes. The performance of the test is investigated through simulation, showing it performs well at detecting outliers when the contaminant observation represents a large shift from the original distribution parameters. An example application to census data is also provided.
This document summarizes a research paper that proposes a portable device called the "Disha Device" to improve women's safety. The device has features like live location tracking, audio/video recording, automatic messaging to emergency contacts, a buzzer, flashlight, and pepper spray. It is designed using an Arduino microcontroller connected to GPS and GSM modules. When the button is pressed, it sends an alert message with the woman's location, sets off an alarm, activates the flashlight and pepper spray for self-defense. The goal is to provide women a compact, one-click safety system to help them escape dangerous situations or call for help with just a single press of a button.
- The document describes a study that constructed physical fitness norms for female students attending social welfare schools in Andhra Pradesh, India.
- Researchers tested 339 students in classes 6-10 on speed, strength, agility and flexibility tests. Tests included 50m run, bend and reach, medicine ball throw, broad jump, shuttle run, and vertical jump.
- The results showed that 9th class students had the best average time for the 50m run. 10th class students had the highest flexibility on average. Strength and performance generally improved with increased class level.
This document summarizes research on downdraft gasification of biomass. It discusses how downdraft gasifiers effectively convert solid biomass into a combustible producer gas. The gasification process involves pyrolysis and reactions between hot char and gases that produce CO, H2, and CH4. Downdraft gasifiers are well-suited for biomass gasification due to their simple design and ability to manage the gasification process with low tar production. The document also reviews previous studies on gasifier configuration upgrades and their impact on performance, and the principles of downdraft gasifier operation.
This document summarizes the design and manufacturing of a twin spindle drilling attachment. Key points:
- The attachment allows a drilling machine to simultaneously drill two holes in a single setting, improving productivity over a single spindle setup.
- It uses a sun and planet gear arrangement to transmit power from the main spindle to two drilling spindles.
- Components like gears, shafts, and housing were designed using Creo software and manufactured. Drill chucks, bearings, and bits were purchased.
- The attachment was assembled and installed on a vertical drilling machine. It is aimed at improving productivity in mass production applications by combining two drilling operations into one setup.
The document presents a comparative study of different gantry girder profiles for various crane capacities and gantry spans. Bending moments, shear forces, and section properties are calculated and tabulated for 'I'-section with top and bottom plates, symmetrical plate girder, 'I'-section with 'C'-section top flange, plate girder with rolled 'C'-section top flange, and unsymmetrical plate girder sections. Graphs of steel weight required per meter length are presented. The 'I'-section with 'C'-section top flange profile is found to be optimized for biaxial bending but rolled sections may not be available for all spans.
This document summarizes research on analyzing the first ply failure of laminated composite skew plates under concentrated load using finite element analysis. It first describes how a finite element model was developed using shell elements to analyze skew plates of varying skew angles, laminations, and boundary conditions. Three failure criteria (maximum stress, maximum strain, Tsai-Wu) were used to evaluate first ply failure loads. The minimum load from the criteria was taken as the governing failure load. The research aims to determine the effects of various parameters on first ply failure loads and validate the numerical approach through benchmark problems.
This document summarizes a study that investigated the larvicidal effects of Aegle marmelos (bael tree) leaf extracts on Aedes aegypti mosquitoes. Specifically, it assessed the efficacy of methanol extracts from A. marmelos leaves in killing A. aegypti larvae (at the third instar stage) and altering their midgut proteins. The study found that the leaf extract achieved 50% larval mortality (LC50) at a concentration of 49 ppm. Proteomic analysis of larval midguts revealed changes in protein expression levels after exposure to the extract, suggesting its bioactive compounds can disrupt the midgut. The aim is to identify specific inhibitor proteins in the midg
This document presents a system for classifying electrocardiogram (ECG) signals using a convolutional neural network (CNN). The system first preprocesses raw ECG data by removing noise and segmenting the signals. It then uses a CNN to extract features directly from the ECG data and classify arrhythmias without requiring complex feature engineering. The CNN architecture contains 11 convolutional layers and is optimized using techniques like batch normalization and dropout. The system was tested on ECG datasets and achieved classification accuracy of over 93%, demonstrating its effectiveness at automated ECG classification.
This document presents a new algorithm for extracting and summarizing news from online newspapers. The algorithm first extracts news related to the topic using keyword matching. It then distinguishes different types of news about the same topic. A term frequency-based summarization method is used to generate summaries. Sentences are scored based on term frequency and the highest scoring sentences are selected for the summary. The algorithm was evaluated on news datasets from various newspapers and showed good performance in intrinsic evaluation metrics like precision, recall and F-score. Thus, the proposed method can effectively extract and summarize online news for a given keyword or topic.
This is an overview of my career in Aircraft Design and Structures, which I am still trying to post on LinkedIn. Includes my BAE Systems Structural Test roles/ my BAE Systems key design roles and my current work on academic projects.
This is an overview of my current metallic design and engineering knowledge base built up over my professional career and two MSc degrees : - MSc in Advanced Manufacturing Technology University of Portsmouth graduated 1st May 1998, and MSc in Aircraft Engineering Cranfield University graduated 8th June 2007.
Covid Management System Project Report.pdfKamal Acharya
CoVID-19 sprang up in Wuhan China in November 2019 and was declared a pandemic by the in January 2020 World Health Organization (WHO). Like the Spanish flu of 1918 that claimed millions of lives, the COVID-19 has caused the demise of thousands with China, Italy, Spain, USA and India having the highest statistics on infection and mortality rates. Regardless of existing sophisticated technologies and medical science, the spread has continued to surge high. With this COVID-19 Management System, organizations can respond virtually to the COVID-19 pandemic and protect, educate and care for citizens in the community in a quick and effective manner. This comprehensive solution not only helps in containing the virus but also proactively empowers both citizens and care providers to minimize the spread of the virus through targeted strategies and education.
An In-Depth Exploration of Natural Language Processing: Evolution, Applicatio...DharmaBanothu
Natural language processing (NLP) has
recently garnered significant interest for the
computational representation and analysis of human
language. Its applications span multiple domains such
as machine translation, email spam detection,
information extraction, summarization, healthcare,
and question answering. This paper first delineates
four phases by examining various levels of NLP and
components of Natural Language Generation,
followed by a review of the history and progression of
NLP. Subsequently, we delve into the current state of
the art by presenting diverse NLP applications,
contemporary trends, and challenges. Finally, we
discuss some available datasets, models, and
evaluation metrics in NLP.
Better Builder Magazine brings together premium product manufactures and leading builders to create better differentiated homes and buildings that use less energy, save water and reduce our impact on the environment. The magazine is published four times a year.
Standards Method of Detailing Structural Concrete.pdf
Paper id 27201445
1. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
CFD Analysis to Study the Effects of Inclined Baffles
on Fluid Flow in a Shell and Tube Heat Exchanger
164
Ajithkumar M.S.1, Ganesha T.2, M. C. Math³
Department of Thermal Power Engineering1, 2, 3,
VTU PG Centre, Mysore/ VTU Belgaum Karnataka India1, 2, 3
Email: ajithkumarmsktpna@gmail.com1, ganeshtnaik88@gmail.com2,
mcmath1018@yahoo.com3,
Abstract- In this paper, an effort has made for Computational Fluid Dynamic (CFD) analysis of a single pass
parallel flow Shell and Tube Heat Exchanger (STHX) with different baffle inclinations. STHX is the most
common and widely used type of heat exchangers in oil refineries, condensers and other large chemical
processing plants. To analyze the performance of STHX, hot fluid has made to flow through tubes and cold fluid
is allowed to flow through the shell. The main objective is to design the STHX with segmental and helical
baffles and to study the flow and temperature field inside the shell side. Also, attempts were made to investigate
the effects and heat transfer characteristics of a STHX for three different baffle inclinations namely 0°, 10°, and
20° for a given baffle cut of 36%. The basic geometry of shell and tube heat exchanger has made by CATIA V5
and meshing has completed by using HYPER MESH (11.0). The flow and temperature fields inside the shell
have studied using ANSYS-FLUENT (6.3). The heat exchanger contains 7 tubes with 600 mm length and shell
diameter 90 mm. The study indicated that flow pattern in the shell side of the heat exchanger with continuous
helical baffle was forced to rotate the fluid, which results in significant increase in heat transfer rate and heat
transfer coefficient per unit pressure drop than segmental baffle STHX. From the CFD simulation results, the
shell side outlet temperature, pressure drop, optimum baffle inclination and optimal mass flow rate were
determined.
Index Terms- STHX, segmental and helical baffles, Helixchanger, CFD, heat transfer rate, pressure drop, baffle
inclination angle…etc.
1. INTRODUCTION
Heat exchangers are used to exchange heat between
two process streams. Typically one fluid is cooled
while the other is heated. Process fluids, usually are
heated or cooled before the process or undergo a
phase change. Heat exchangers are used in cooling,
heating, condensation, boiling or evaporation
purposes. They are widely used in petroleum
refineries, chemical plants, petrochemical plants,
natural gas processing, air-conditioning, refrigeration,
and automotive applications. One common example
of a heat exchanger is the radiator in a car, in which it
transfers heat from the water (hot engine-cooling
fluid) in the radiator to the air passing through the
radiator [1] [2] [3].
There are two main types of heat exchangers:
· Direct contact heat exchanger, where both
media between which heat is exchanged are
in direct contact with each other, and
· Indirect contact heat exchanger, where both
media are separated by a wall through which
heat is transferred so that they never mix.
1.1 History of the study
In addition to the basic need for transferring heat there
are certain additional requirements which tend to be
specific to the industry, in which they are employed.
For example, the exchanger used in automotive and
aviation industry need to be lightweight. These
exchangers as well as those used in commercial and
domestic refrigeration tend to use the same types of
fluid in many applications. The exchangers used in
chemical process industry tend to be used for a wide
variety of fluid types with different degree of
cleanliness. In contrast, the exchangers used in
cryogenic applications invariable handle relatively
clean fluids. These and other similar industry specific
requirements have resulted in development of
different types of exchanger ranging from the
conventional shell and tube heat exchanger to other
tubular and non-tubular exchangers of varying degree
of compactness [3].
Shell and tube heat exchanger (STHX) is a
type of heat exchanger used for efficient heat transfer
from one fluid to other fluid that consist of series of
finned tubes in which one of the fluid runs in the tube
and the other fluid run over the tube to be heated or
cooled during the heat exchange process [4]. Over the
years, significant research and development efforts
2. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
165
are devoted to better understand the shell side
geometry. A variety of different strategies are
available to process and equipment designers to
improve industrial heat transfer [3].
Shell and Tube heat exchanger has larger
surface area with a small shape. This type of heat
exchanger is good mechanical layout and good for
pressurized operation. Shell and tube heat exchanger
is easy to clean. The shell and tube heat exchanger is
made up of different type of materials in which
selected materials is used for operating pressure and
temperature [4].
The major problem of shell and tube heat
exchanger that it causes a larger pressure drop and
results in dead zone between adjacent baffles. It leads
to an increase of fouling resistance and the dramatic
zigzag flow causes a high risk of vibration failure on
tube bundle [4].
1.2 Desirable features of heat exchangers
To obtain maximum heat exchanger
performance at the lowest possible operating and
capital costs without comprising the reliability, the
following features are required of an Exchanger:
(1) Higher heat transfer coefficient and larger heat
transfer area.
(2) Lower pressure drop.
2. SELECTION FOR SHELL AND TUBE HEAT
EXCHANGERS (STHXS)
More than 35-40 % of heat exchangers are of
shell and tube type due to their robust geometrical
construction, easy maintenance and possible
upgrades. Rugged safe construction, availability in a
wide range of materials, mechanical reliability in
service, availability of standards for specifications and
designs, long collective operating experience and
familiarity with the designs are some of the reasons
for its wide usage in industry. Fig. 1 shows a STHX.
Fig.1. Shell and tube heat exchanger (STHX)
3. HELIXCHANGER AND SEGMENTAL HEAT
EXCHANGER
Baffle is an important shell side component
of STHXs. It supports the tube bundles, and form
flow passages for the shell side fluid in conjunction
with the shell. The most commonly used baffle is the
segmental baffle, which forces the fluid in a zigzag
manner, thus improving the heat transfer but with a
large pressure drop penalty. This type of heat
exchanger has been well developed and probably is
still the most commonly used type of the shell and
tube heat exchanger.
The major drawbacks of the conventional
shell and tube heat exchangers with segmental baffles
are threefold: firstly it causes a large side pressure
drop; secondly it results in a dead zone in each
component between two adjacent segmental baffles,
leading to an increase of fouling resistance; thirdly the
dramatic zigzag flow pattern also causes high risk of
vibration failure on tube bundle. [9].
A new type of baffle, called helical baffle,
provides further improvement. This type of baffle was
first proposed by D.Kral and J. Nemcansky, (1993)
[12], where they investigated the flow field patterns
produced by such helical baffle geometry with
different helix angles. They found that these flow
patterns were much close to plug flow conditions,
which was expected to reduce shell side pressure drop
and to improve heat transfer performance. Fig. 2
shows an isometric view of baffles and tubes in
STHX with 20° baffle inclination.
3.1 Segmental-baffle shell and tube heat exchanger
Baffle spacing (B) is the center line distance
between two adjacent baffles, Baffle is provided with
a cut (Bc) which is expressed as the percentage of the
segment height to shell inside diameter. Baffle cut can
vary between 15% and 45% of the shell inside
diameter. In the present study 36% baffle cut (Bc) is
used.
Fig.2. Isometric view of baffles and tubes in STHX
with 20° baffle inclination
The effectiveness and cost are two important
parameters in heat exchanger design. So, in order to
improve the thermal performance at a reasonable cost
of the Shell and tube heat exchanger, baffles in the
present study are provided with some inclination in
order to maintain a reasonable pressure drop in heat
exchanger [1].
3.2 Helical-baffle shell and tube heat exchanger
3. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
166
The concept of helical baffle heat exchangers
was developed for the first time in Czechoslovakia.
The Helical baffle heat exchanger, also known as
‘Helixchanger’, is a superior shell and tube exchanger
solution that removes many of the inherent
deficiencies of conventional segmental baffle
exchangers. Helical baffle heat exchangers have
shown very effective performance especially for the
cases in which the heat transfer coefficient in shell
side is controlled; or less pressure drop and less
fouling are expected [3].
The Helix changer design provides:
· Enhanced (Heat transfer performance/ Shell-side
pressure drop) ratio.
· Reduced fouling characteristics.
· Effective protection from flow-induced tube
vibrations.
· It results in lower capital costs, reduced
operating costs, lower maintenance costs and
consequently, significant lower total life
cycle costs.
· For existing plants, the Helixchanger design
helps to increase the capacity while lowering
maintenance cost, plot space and energy
costs.
It is better to consider the Helixchanger option when
investigating the following:
· Plant upgrade with replacement tube
bundles.
· Capacity expansion with limited plot space.
· Reduce fouling problems and frequent
downtime.
Fig.3. Helical baffled shell and tube heat exchanger
(Helixchanger)
On the shell side the conventional segmental
baffles exhibit higher pressure difference to produce
sufficiently high heat transfer rate. Therefore fresh
look into the baffle arrangement is needed. So, use of
helical shaped baffles is proposed, because the fluid
flow pattern, within the shell, may significantly
influence the heat exchanger efficiency [3].
4. COMPUTATIONAL MODELING AND
SIMULATION
Computational Fluid Dynamics (CFD)
provides a qualitative (and sometimes even
quantitative) prediction of fluid flows by means of:
· Mathematical modeling (partial differential
equations)
· Numerical methods (discretization and
solution techniques)
· Software tools (solvers, pre- and post-processing
utilities) [10].
To simplify numerical simulation, following
assumptions have made:
· The shell side fluid processes constant
thermal properties.
· The fluid flow and heat transfer processes are
turbulent and in steady state.
· The leak flows between tube and baffle and
that between baffles and shell are neglected.
· The natural convection induced by the fluid
density variation is neglected.
· The tube wall temperature kept constant in
the whole shell side.
· The heat exchanger is well insulated hence
the heat loss to the environment is totally
neglected.
4.1 Geometry modeling
The model is designed according to TEMA
(Tubular Exchanger Manufacturers Association)
Standards Gaddis [13], using CATIA V5 software as
shown in Fig.5. Design parameters and fixed
geometric parameters have been taken similar to
Ozden et al. [14], as indicated in Table 1.
Fig.4. Isometric view of baffles and tubes in STHX
with 20° baffle inclination
Table 1. Geometric dimensions of shell and tube heat
exchanger [14]
Sl.
No.
Description Unit Value
1 Heat exchanger length, L mm 600
2 Shell inner diameter, Di mm 90
3 Tube outer diameter, do mm 20
4 Tube bundle geometry
and pitch triangular
mm 30
4. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
167
5 Number of tubes, Nt - 7
6 Number of baffles. Nb - 6
7 Central baffle spacing, B mm 86
8 Baffle inclination angle,θ degree 0, 10,20
4.2 Grid generation
Mesh generation is performed using HYPER
MESH (11.0). The surfaces of the model are meshed
using Triangular elements. The fluid volume is
meshed using tetrahedral elements. Mesh size selected
are fine with node number around 50,000 and element
number around 2, 000, 00. In order to capture both the
thermal and velocity boundary layers the entire model
is discretized using 2D triangular mesh elements for
all the surfaces and tetrahedral mesh elements for 3D
volume fluid elements, which are accurate and
involve less computation effort. The entire geometry
is divided into 6 components, namely, inlet, outlet,
tube, shell, baffle and fluid.
Fig.5. Discretized fluid domain for segmental-baffle
STHX with uniform volume 3D tetrahedral mesh
Fig.6. Discretized solid domain for helical-baffle
STHX with uniform surface 2D triangular mesh
The heat exchanger is discretized into solid
and fluid domains to have better control over the
number of nodes. The fluid mesh is made finer then
solid mesh for simulating conjugate heat transfer
phenomenon. The entire 3D fluid domains are as
shown in Fig.5 and 2D surface meshing is shown in
Fig. 6.
5. TURBULENCE MODELING
Turbulent flows have some characteristic
properties which distinct them from laminar flows. In
this study, realizable k-epsilon (k-ε 2 eqn.) turbulence
model has tried.
5.1 k-ε turbulence model
The k-epsilon (k-ε 2 eqn.) model has been
implemented in most general purpose CFD codes and
is considered the industry standard model. It has
proven to be stable and numerically robust and has a
well-established regime of predictive capability. For
general purpose simulation, the model offers a good
compromise in term of accuracy and robustness.
5.2 Realizable k - ε model
This model differs from the standard k - ε
model in that it features a realizability constraint on
the predicted stress tensor, thereby giving the name of
realizable k - ε model. The difference comes from
correction of the k-equation where the normal stress
can become negative in the standard k - ε model for
flows with large strain rate.
6. GOVERNING EQUATIONS
The governing equations of the flow are modified
according to the conditions of the simulated case.
Since the problem is assumed to be steady, time
dependent parameters are dropped from the equations.
The resulting equations are:
· Conservation of mass :∇.(ρVr)=0. (1)
· X-momentum:∇.(ρuVr)=-(∂p/∂x)+(∂τxx/∂x)
+(∂τyx/∂y) + (∂zx/∂z) (2)
· Y-momentum:∇.(ρvVr)=-(∂p/∂y)+(∂τxy/∂x)
+(∂zy/∂y) + (∂zx/∂z) +ρ g (3)
· Z-momentum:∇.(ρwVr)=-(∂p/∂z)+(∂τxz/∂x)
+ (∂yz/∂y) + (∂zz/∂z) +ρ g (4)
· Energy :∇.(ρeVr) = -p ∇.Vr +∇. (k.∇ T)
+qφ (5)
In Eq. (5), φ is the dissipation function that can
be calculated from; φ = μ [ 2[(∂u/∂x)² +(∂v/∂y)²
+(∂w/∂z)²] + (∂u/∂y + ∂v/∂x)² +(∂u/∂z + ∂w/∂z)²
+(∂v/∂z + ∂w/∂y)² +λ(∇.Vr)² (6)
7. BOUNDARY CONDITIONS
The working fluid in the shell side, shell inlet
temperature, constant wall temperature assigned to the
tube walls, gauge pressure assigned to the outlet
nozzle, inlet velocity profile assumed, slip condition
assigned to all surfaces, heat flux boundary condition
assigned to the shell outer wall (excluding the baffle
shell interfaces), assuming the shell is perfectly
insulated, are used in the CFD analysis are given in
the following table 2. [1] [2].
5. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
168
Table 2. Boundary conditions used in CFD analysis
Sl.No. Quantities Condition/value
1 Working fluid Water
2 Shell inlet temperature 300K
3 Tube wall temperature 450K
4 Gauge pressure Zero Pascal
5 Inlet velocity profile Uniform m/sec
6 Slip No slip
7 Heat flux Zero W/m²
8. RESULTS AND DISCUSSION
Fig. 7 to 12 shows the temperature contours
and Fig. 13 to 18 shows the pressure contours
obtained for different baffle inclinations such as such
as 0 degree, 10 degree and 20 degree for segmental as
well as helical baffle shell and tube heat exchangers.
8.1 Variation of temperature
Fig. 7 to 12 shows the temperature contour
plots for both segmental and helical baffle shell and
tube heat exchangers across the cross section at
different inclinations of baffle along the length of heat
exchanger.
8.1.1 For segmental baffle (m = 1kg/s)
Fig.7. Temperature distribution for 0 degree baffle inclination
Fig.8. Temperature distribution for 10 degree baffle inclination
6. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
169
Fig.9.Temperature distribution for 20 degree baffle inclination
For Helical Baffle (m = 1kg/s)
Fig.10. Temperature distribution for 0 degree baffle inclination
Fig.11. Temperature distribution for 10 degree baffle inclination
7. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
170
Fig.12. Temperature distribution for 20 degree baffle inclination.
5.3 Variation of Pressure
Fig.13 to 18 shows pressure distribution
across the shell and tube heat exchanger. With the
increase in Baffle inclination, pressure drop inside the
shell decreases and then increases. The contours of
static pressure are shown in Fig. 13 to 18 gives detail
idea.
For Segmental Baffle (m = 1kg/s)
Fig.13. Pressure distribution across shell at 0 degree baffle inclination
Fig.14. Pressure distribution across shell at 10 degree baffle inclination
8. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
171
Fig.15. Pressure distribution across shell at 20 degree baffle inclination
For Helical Baffle (m = 1kg/s)
Fig.16. Pressure distribution across shell at 0 degree baffle inclination
Fig.17. Pressure distribution across shell at 10 degree baffle inclination
9. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
172
Fig.18 Pressure distribution across shell at 20 degree baffle inclination
Table 3. Overall calculations and comparison of segmental and helical baffle STHX
STHX
baffle
geometry
Mass
flow
rate
[kg/s]
Baffle
inclination
[degree]
Outlet
temperature
[K]
Pressure
difference
[Pa]
Heat
transfer
coefficient
[W/m²-K]
Heat
transfer
rate [W]
Segmental
baffle
0.5
0 325.44 77.71 1382.91 53413.45
10 325.86 76.74 1409.89 54351.24
20 325.76 77.54 1403.10 54080.64
1.0
0 323.56 313.57 2372.96 98826.53
10 324.07 308.32 2433.59 101166.33
20 323.92 313.14 2417.51 100472.57
2.0
0 320.40 1278.25 4113.85 171408.84
10 322.83 1239.85 4618.19 191969.7
20 322.74 1259.66 4516.99 191031.13
Helical
baffle
0.5
0 328.73 73.68 1472.58 60421.21
10 328.51 76.90 1465.02 59993.09
20 328.55 78.34 1473.00 59832.55
1.0
0 326.75 295.29 2742.43 112506.00
10 326.29 307.14 2735.69 111964.45
20 326.69 318.20 2754.77 111762.85
2.0
0 325.47 1182.06 5224.31 214288.23
10 325.21 1226.69 5196.56 212612.11
20 325.24 1255.71 5223.01 211776.39
Table 3. shows the overall calculations and
comparison of CFD analysis results for both circular
segmental-baffle shell and tube heat exchanger and
helical-baffle shell and tube heat exchanger. The
study focused on the variation of shell side pressure
drop, heat transfer coefficient and heat transfer rate
with respect to different mass flow rates and under
different baffle orientations.
It has been seen that for segmental baffle
shell and tube heat exchanger, shell side pressure drop
decreased and then slightly increased with an increase
in baffle inclination angle at a given mass flow rate.
Corresponding variations in heat transfer coefficient
and heat transfer rate were occurred. When the
pressure drop decreased the heat transfer coefficient
and rate of heat transfer were increased. But in the
case of helical heat exchanger the value of shell side
pressure drop increased continuously and thus heat
transfer coefficient and heat transfer rate reduced with
increased baffle inclinations at a given mass flow rate.
8.3 Effect of baffle inclination on outlet
temperature and pressure drop
From the CFD simulation results, for fixed
tube wall and shell inlet temperatures, shell side outlet
temperature and pressure drop values for varying fluid
flow rates are provided in table 3. In this work, mass
flow rate values are changed from 0.5kg/s to 2.0kg/s.,
Table 3 shows that the corresponding values of shell
outlet temperature are decreased slightly and the
pressure drop, heat transfer coefficient and heat
transfer rate values are increased. The Outlet
temperature variation with baffle inclination angle
also given in the Table 5, which shows that there is no
10. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
173
much variation in shell outlet temperature. The
average outlet temperature varies in between 325K to
328K while calculating from constant shell inlet
temperature 300K. Compared to segmental baffle
shell and tube heat exchanger, helical baffle shell and
tube heat exchanger has slight higher values of outlet
temperatures.
8.3.1 Segmental baffle STHX
Fig.19 Effect of baffle inclination on outlet
temperature
It is found that for segmental baffle STHX
the shell outlet temperature decreases with increasing
mass flow rates as expected even the variation is
minimal as shown in Fig. 19. It is found that for three
mass flow rates 0.5 kg/s, 1 kg/s, and 2 kg/s there is no
much effect on outlet temperature of the shell even
though the baffle inclination is increased from 0° to
20°.
Fig.20 Effect of baffle inclination on pressure drop
However the shell-side pressure drop is
slightly decreased with increase in baffle inclination
angle i. e., as the inclination angle is increased from
0° to 20°. For the given geometry the mass flow rate
must be below 2 kg/s, if it is increased beyond 2 kg/s
the pressure drop increases rapidly with little variation
in outlet temperature as shown in Fig. 20. It can also
be observed that shell and tube heat exchanger with
10° baffle inclination angle results in a reasonable
pressure drop with maximum shell outlet temperature.
Hence it can be concluded shell and tube heat
exchanger with 10° baffle inclination angle results in
better performance compared to 20° and 0° inclination
angles. The values of heat transfer rate and pressure
drop at 10◦ (m = 1.0kg/s) are 1, 01,166.33W and
308.32Pa respectively.
8.3.2 Helical baffle STHX
Fig.21 Effect of baffle inclination on outlet
temperature
In helical baffle STHX, the shell outlet
temperature first decreased and then increased with
increase in baffle inclination for a constant mass flow
rate as shown in fig.5.21. It is found that for three
mass flow rates 0.5 kg/s, 1 kg/s, and 2 kg/s there is no
much effect on outlet temperature of the shell as
baffle inclination is increased from 0° to 20°, even
though maximum value is at small mass flow rate.
Fig.22 Effect of baffle inclination on pressure drop
It is found that shell-side pressure drop is
slightly increased with increase in baffle inclination
angle i. e., as the inclination angle is increased from
0° to 20°. For the given geometry the mass flow rate
must be below 2 kg/s, if it is increased beyond 2 kg/s
the pressure drop increases rapidly with little variation
in outlet temperature as shown in fig.5.22. So it can
be concluded that in helical baffle shell and tube heat
exchanger with 0° baffle inclination angle results in
better performance compared to 10° and 0° inclination
angles. The values of heat transfer rate and pressure
drop at 0◦ (m = 1.0kg/s) are 1, 12,506 W and 295.29
Pa respectively.
8.4 Comparison of pressure drop and the rate of
heat transfer for segmental and helical baffle
STHXS (m = 2.0kg/s)
Fig.23 shows the comparison of shell side
pressure drop in segmental and helical baffle shell and
11. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
174
tube heat exchanger for the mass flow rate of 2.0kg/s.
It has been seen that for segmental baffle shell and
tube heat exchanger, pressure drop decreased first and
then increased. But in the case of helical baffle shell
and tube heat exchanger the value of shell side
pressure drop continuously increases. Thus the
optimum vale of shell side pressure drop for
segmental baffle heat exchanger can be taken under
10 degree baffle angle. In the case of helical baffle
heat exchanger pressure drop increases with increase
in baffle angle, so we can take 0 degree as the
optimum baffle inclination with lowest pressure drop
value.
Fig.23 Comparison of shell side pressure drop
Fig.24 shows the comparison of heat transfer
rate for segmental and helical baffle shell and tube
heat exchangers under the mass flow rate of 2.0kg/s.
For segmental baffle arrangement heat transfer rate
gradually increases. But in helical baffle shell and
tube heat exchanger the value of heat transfer rate is
almost uniform, but slightly maximum at zero degree
baffle orientation.
Fig.24 Comparison of heat transfer rate
By comparing the fig.24 and fig.25 the
optimum baffle inclination angle for segmental baffle
shell and tube heat exchanger is 10◦, which shows the
minimum pressure drop with a better heat transfer
value. In the case of helical baffle shell and tube heat
exchanger the optimum baffle inclination angle can be
taken as 0◦, since above zero degree baffle inclination
there is a rapid rise in shell side pressure drop with
less variation in heat transfer rate.
9. CONCLUSION
Considering the heat transfer rate for 1.0kg/s
mass flow rate in the case of segmental baffle heat
exchanger under 100 baffle inclination is
101.16633kW. Then by taking the heat transfer rate
for helical baffle shell and tube heat exchanger for the
same mass flow rate (m= 1.0kg/s), under 00 baffle
inclination is 112.506 kW. So from this study the
better option for a shell and tube heat exchanger is a
helical baffle at zero degree than a segmental baffle
with 10 degree baffle inclination. So it can be
summarized as follows:
· The shell side of a small shell and tube heat
exchanger is modeled with sufficient detail to
resolve the flow and temperature fields.
· For the given geometry the mass flow rate must
be below 2.0kg/s, if it is increased beyond 2.0kg/s
the pressure drop increases rapidly with little
variation in outlet temperature.
· In segmental baffle STHX it is observed that 10°
baffle inclination angle results in a reasonable
pressure drop with maximum shell outlet
temperature and higher heat transfer rate.
· It is observed that at 0° baffle inclination angle
helical baffle STHX results in better performance
compared to 10° and 0° inclination angles, i. e.,
with less pressure drop, maximum shell outlet
temperature and .higher heat transfer rate.
· By comparing both segmental and helical baffle
STHXs, the helical baffle with 0◦ inclination
results in better performance than segmental
baffle with 10◦ baffle inclination, i. e., minimum
pressure drop with maximum heat transfer rate.
REFERENCES
[1] Rajagapal Thundil Karuppa Raj and Srikanth
Ganne, 2012. “Shell side numerical analysis of a
shell and tube heat exchanger considering the
effects of baffle inclination angle on fluid flow”,
International journal of Thermal Science, Vol.
No. 4, pp. 1165-1174.
[2] Abdur Rahim and S.M. Saad Jameel, Oct 19-20,
2012. “Shell side CFD analysis of a small shell
and tube heat exchanger considering the effects
of baffle inclination on fluid flow”, National
Conference on Trends and Advances in
Mechanical Engineering, Vol. No. 1, pp. 167-
173.
[3] Sunil S. Shinde and Pravinkumar V. Hadgekar,
Aug 2013. “Numerical comparison on shell side
performance of helixchanger with center tube
with different helix angles”, International Journal
of Science and Research Publications, Vol. 3,
Issue 8, ISSN 2250-3153.
12. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
175
[4] P.S. Gowthaman Ȧ. and S.Sathish, February
2014. “Analysis of Segmental and Helical Baffle
in Shell and tube Heat Exchanger”, International
Journal of Current Engineering and Technology,
E-ISSN 2277 – 4106, P-ISSN 2347 – 5161.
[5] Mukherjee R., Nov. 1992. “Use Double
Segmental Baffles in Shell and Tube Heat
Exchangers,” Chem. Eng. Progress, 88 (11), pp.
47–52.
[6] Tinker, T., (1958). “Shell side Characteristics of
Shell-and-tube Heat Exchangers: A
[7] Simplified Rating System for Commercial Heat
Exchangers” Trans. ASME, 80, 36–52.
[8] Prasanna. J, H.R. Purushothama, Devaraj K. and
Murugeshan, June-July 2013. “Numerical
analysis of Hydrodynamic and heat transfer
effects of Shell and tube heat exchanger for
different baffle space and cut”, Mechanica
Confab, Vol. 2, No. 4, ISSN 2320-2491.
[9] S.P. Walde, V.M. Kriplani, (April 2012).
“Review of heat transfer enhancement in
different types of baffles and their orientations”,
International Journal of Engineering Science and
Technology (IJEST), Vol. 4 No.04, ISSN 0975-
5462.
[10]Sunil S. Shinde, Samir S.Joshi and Dr. S.
Pavithran, Jan-Feb 2012. “Performance
improvement in single phase tubular heat
exchanger using continuous helical baffles”,
International Journal of Engineering Researches
applications (IJERA), Vol. 2, Issue 1, pp. 1141-
1149, ISSN 2248-9622.
[11]Savitri Patel and D.S. Patel, March 2014.
“Application of CFD in STHE: A Review”,
International Journal of Engineering Science and
Innovative Technology (IJESIT), Vol.3, Issue 2,
ISSN 2319-5967.
[12]D.Kral and J. Nemcansky, (1993). “The
Helixchanger-Helically Baffled heat exchanger”,
ICHMT International Symposium on New
Developments in Heat Exchanger, Portugal, pp.
467-477.
[13]Gaddis D. 2007, Standards of the Tubular
Exchanger Manufacturers Association, TEMA
Inc, 9th ed., Tarrytown, N. Y., USA.
[14]Ozden E., Tari I. 2010. “Shell Side CFD Analysis
of a Small Shell-and-Tube Heat Exchanger”,
Energy Conversion and Management, 51, 5, pp.
1004-1014.
[15]Sombat Tamna, Warakom Nerdnoi, Chinaruk
Thianpong and Pongjet Promvonge, Oct. 2011.
“Numerical Heat Transfer Study in a Square
Channel with Zigzag-Angled Baffles”,
International Conference on Mechanical
Engineering, Vol. No.1, pp. 1-9.