The document summarizes a computational fluid dynamics (CFD) analysis of the thermal performance of a circular journal bearing. The analysis was conducted using two approaches: 1) iso-thermal, which assumes constant viscosity, and 2) thermo-hydrodynamic, which accounts for viscosity variation with temperature. Higher pressures, temperatures, and oil film forces were observed in the iso-thermal approach compared to the thermo-hydrodynamic approach, which more accurately models the viscosity decrease with increasing temperature. The rise in these parameters increased with journal speed for both approaches, but was greater for the iso-thermal case that neglects viscosity variation effects.
This document discusses the optimization of parameters for a gas-lubricated hydrodynamic foil journal bearing to achieve maximum load carrying capacity using genetic algorithms. The load carrying capacity is dependent on parameters like eccentricity ratio, compliance, angular speed, and attitude angle. Using MATLAB, these parameters were optimized using a genetic algorithm tool to achieve a maximum load of 3.8854. The ranges of compliance from 0.00413 to 0.0043 and angular speed from 61500 to 67500 rpm were defined, within which the optimized load carrying capacity could still be achieved, providing flexibility in design constraints. In conclusion, genetic algorithms were able to optimize the load carrying capacity of a gas foil bearing by tuning the values of influential design
Design & optimization of LNG-CNG cylinder for optimum weightijsrd.com
In current automobile sector, the weight of the vehicle is too important to increase the efficiency of the vehicle. There are too many component or subassemblies are in the automobile vehicle. In this paper the weight of the HYDROGEN fuel tank is optimized by applying the composite material concept with the existing material of the fuel tank. Initially the dimensional calculation for the existing pressure vessel and compare with the existing cylinder and then the FEA ( Finite Element Analysis) applied on the cylinder and material optimize up to the stress reaching equivalent to the stress of the existing cylinder. After that the dimension of the cylinder are finalize. The analysis yields a weight reduction of fuel tank.
Thermohydrodynamic analysis of plain journal bearing with modified viscosity ...IAEME Publication
This document summarizes previous research on thermohydrodynamic analysis of journal bearings. It discusses governing equations used in such analyses, including the Reynolds equation and energy equations. It also discusses different viscosity-temperature relationships that have been used and highlights how the authors have modified an existing two-degree viscosity-temperature equation to a three-degree polynomial equation to better predict viscosity variations with temperature in journal bearings. The aim of the paper is to predict pressure and temperature distributions in plain journal bearings using this modified viscosity-temperature relationship.
Stability Analysis of Journal Bearing Using Electro Rheological Fluid by Fini...ijsrd.com
in rotating machinery, the damping of structure which supports the rotating shaft has significant effect in machine vibration. Therefore by controlling the lubricant properties, the dynamic behavior of the system can be controlled. The objective of this paper is to study the dynamic behavior of a rotor supported by a journal bearing and fed with Electro-rheological (ER) fluid. ER fluids can be used to create ‘smart’ journal bearings & vibration controllers can be constructed to control the Stability of the ER fluid lubricated bearings. The ER fluid behaves like a Bingham fluid with a higher viscosity when electric field is applied, and restores its property when the field is removed. A reversible change in viscosity occurs in milliseconds with the electric field applied.
Performance Characteristic of Infinitely Short BearingIJSRD
An attempt has been made to analyse to performance of an infinitely rough short bearing. Here in solving the associated Reynold`s type equation in new boundary conditions involving the standard deviation associated with roughness has been used. The pressure, load carrying capacity and friction are calculated. It is found that the roughness parameter significantly affects all the above performance characteristic. It is observed that effect due to the roughness compounded by taking the effect of standard deviation on the boundary conditions.
CFD Analysis of Fluid Film Journal Bearing: A ReviewIRJET Journal
This document provides a review of computational fluid dynamics (CFD) analysis that has been performed on fluid film journal bearings. It summarizes 14 papers that analyzed pressure and temperature distribution in journal bearings under various conditions. These papers used CFD to study how parameters like speed, load, eccentricity ratio, and lubricant properties affect the pressure and temperature fields. The document also summarizes 5 papers that used fluid-structure interaction (FSI) methods to study deformation of the bearing surface. And it summarizes 6 papers that analyzed how parameters influence the load carrying capacity of journal bearings. The objective of the review was to evaluate how CFD analysis has provided insights into journal bearing performance.
Investigation of Extrusion of Lead experimentally from Round section through ...inventy
ABSTRACT :The changes of die angle, area reduction in dies, loading rate on the final extruded products, extrusion pressures of lead of circular cross sections has been investigated experimentally. The proposed method is successfully adapted to the forward extrusion of the equilateral triangular section from round billet through converging dies of different area reductions. Computation of extrusion pressure at various area reductions and calculations of different parameters (stress, strain etc.) in wet condition.
Keywords - Extrusion of Triangular section, Converging Dies at different area reductions, Friction Factor, Extrusion Pressure
Conical Fluidized Beds - Case Study for a Gas Solid System Involving Coarse P...IRJET Journal
This document summarizes research on fluidization characteristics in conical fluidized beds. Three key points:
1) Conical fluidized beds were studied using silica sand particles in beds with cone angles of 10 and 20.5 degrees. Three distinct flow regimes - fixed bed, partially fluidized bed, and fully fluidized bed - were observed as gas velocity increased.
2) Parameters like initial bed height and cone angle affected minimum fluidization velocities and maximum pressure drops. These values increased with greater bed height and cone angle.
3) Models were developed based on experiments to predict minimum fluidization velocities and pressure drops in conical beds, taking into account factors like particle properties, bed geometry, and gas velocity
This document discusses the optimization of parameters for a gas-lubricated hydrodynamic foil journal bearing to achieve maximum load carrying capacity using genetic algorithms. The load carrying capacity is dependent on parameters like eccentricity ratio, compliance, angular speed, and attitude angle. Using MATLAB, these parameters were optimized using a genetic algorithm tool to achieve a maximum load of 3.8854. The ranges of compliance from 0.00413 to 0.0043 and angular speed from 61500 to 67500 rpm were defined, within which the optimized load carrying capacity could still be achieved, providing flexibility in design constraints. In conclusion, genetic algorithms were able to optimize the load carrying capacity of a gas foil bearing by tuning the values of influential design
Design & optimization of LNG-CNG cylinder for optimum weightijsrd.com
In current automobile sector, the weight of the vehicle is too important to increase the efficiency of the vehicle. There are too many component or subassemblies are in the automobile vehicle. In this paper the weight of the HYDROGEN fuel tank is optimized by applying the composite material concept with the existing material of the fuel tank. Initially the dimensional calculation for the existing pressure vessel and compare with the existing cylinder and then the FEA ( Finite Element Analysis) applied on the cylinder and material optimize up to the stress reaching equivalent to the stress of the existing cylinder. After that the dimension of the cylinder are finalize. The analysis yields a weight reduction of fuel tank.
Thermohydrodynamic analysis of plain journal bearing with modified viscosity ...IAEME Publication
This document summarizes previous research on thermohydrodynamic analysis of journal bearings. It discusses governing equations used in such analyses, including the Reynolds equation and energy equations. It also discusses different viscosity-temperature relationships that have been used and highlights how the authors have modified an existing two-degree viscosity-temperature equation to a three-degree polynomial equation to better predict viscosity variations with temperature in journal bearings. The aim of the paper is to predict pressure and temperature distributions in plain journal bearings using this modified viscosity-temperature relationship.
Stability Analysis of Journal Bearing Using Electro Rheological Fluid by Fini...ijsrd.com
in rotating machinery, the damping of structure which supports the rotating shaft has significant effect in machine vibration. Therefore by controlling the lubricant properties, the dynamic behavior of the system can be controlled. The objective of this paper is to study the dynamic behavior of a rotor supported by a journal bearing and fed with Electro-rheological (ER) fluid. ER fluids can be used to create ‘smart’ journal bearings & vibration controllers can be constructed to control the Stability of the ER fluid lubricated bearings. The ER fluid behaves like a Bingham fluid with a higher viscosity when electric field is applied, and restores its property when the field is removed. A reversible change in viscosity occurs in milliseconds with the electric field applied.
Performance Characteristic of Infinitely Short BearingIJSRD
An attempt has been made to analyse to performance of an infinitely rough short bearing. Here in solving the associated Reynold`s type equation in new boundary conditions involving the standard deviation associated with roughness has been used. The pressure, load carrying capacity and friction are calculated. It is found that the roughness parameter significantly affects all the above performance characteristic. It is observed that effect due to the roughness compounded by taking the effect of standard deviation on the boundary conditions.
CFD Analysis of Fluid Film Journal Bearing: A ReviewIRJET Journal
This document provides a review of computational fluid dynamics (CFD) analysis that has been performed on fluid film journal bearings. It summarizes 14 papers that analyzed pressure and temperature distribution in journal bearings under various conditions. These papers used CFD to study how parameters like speed, load, eccentricity ratio, and lubricant properties affect the pressure and temperature fields. The document also summarizes 5 papers that used fluid-structure interaction (FSI) methods to study deformation of the bearing surface. And it summarizes 6 papers that analyzed how parameters influence the load carrying capacity of journal bearings. The objective of the review was to evaluate how CFD analysis has provided insights into journal bearing performance.
Investigation of Extrusion of Lead experimentally from Round section through ...inventy
ABSTRACT :The changes of die angle, area reduction in dies, loading rate on the final extruded products, extrusion pressures of lead of circular cross sections has been investigated experimentally. The proposed method is successfully adapted to the forward extrusion of the equilateral triangular section from round billet through converging dies of different area reductions. Computation of extrusion pressure at various area reductions and calculations of different parameters (stress, strain etc.) in wet condition.
Keywords - Extrusion of Triangular section, Converging Dies at different area reductions, Friction Factor, Extrusion Pressure
Conical Fluidized Beds - Case Study for a Gas Solid System Involving Coarse P...IRJET Journal
This document summarizes research on fluidization characteristics in conical fluidized beds. Three key points:
1) Conical fluidized beds were studied using silica sand particles in beds with cone angles of 10 and 20.5 degrees. Three distinct flow regimes - fixed bed, partially fluidized bed, and fully fluidized bed - were observed as gas velocity increased.
2) Parameters like initial bed height and cone angle affected minimum fluidization velocities and maximum pressure drops. These values increased with greater bed height and cone angle.
3) Models were developed based on experiments to predict minimum fluidization velocities and pressure drops in conical beds, taking into account factors like particle properties, bed geometry, and gas velocity
Experimental Method to Analyse Limit Load in Pressure VesselIJMER
Pressure vessel contains with different inlet & outlet openings called nozzle or valves. The design parameter of these valves may different in one pressure vessel. These valves cause geometric discontinuity of the pressure vessel wall hence stress concentration may occur around the valve or nozzle. Since due to the high stress concentration there may be the chances of failure of vessel junction. Hence detail stress distribution analysis needs to be done for pressure vessel. Determination of limit pressure at different location on pressure vessel by using finite element method is less time consuming
and it avoid complex mathematical work at difficult geometries. So, it is essential to validate the result.
Experiments is conducted on oblique nozzle (450 with shell axis) & result obtained are used to validate
the finite element results. Distortion measurement test by measuring change in diameter of vessel after
vessel is pressurized using water. Twice elastic slope method & Tangent intersection method are used to
find out limit load estimation of cylindrical vessel with oblique (450) nozzle.
Conical Fluidized Beds - Case Study for a Gas Solid System Involving Wheat Fl...IRJET Journal
This document summarizes a study on fluidization of wheat flour and additive particles in a conical fluidized bed. Key points:
- Conical fluidized beds can handle particles of varying sizes and cohesive particles better than traditional cylindrical beds due to varying gas velocity.
- An experiment was conducted using a two-dimensional conical bed with a 20.5° cone angle. Wheat flour and crushed wheat were used as particles.
- Pressure drop and fluidization properties were measured for beds containing various ratios of flour and crushed wheat additive. The study aimed to improve fluidization of cohesive flour using the crushed wheat additive.
Effect of non uniform heat source for the ucm fluid over a stretching sheet w...IAEME Publication
This document summarizes a study on the effect of a non-uniform heat source on fluid flow over a stretching sheet with an applied magnetic field. The fluid is modeled as an upper-convected Maxwell (UCM) fluid. Similarity transformations are used to reduce the governing non-linear partial differential equations to an ordinary differential equation, which is then solved numerically using a fourth-order Runge-Kutta method. Graphical results are presented showing the effects of various parameters like the elastic parameter, Eckert number, magnetic parameter, and non-uniform heat source on the velocity and temperature profiles. The key findings are that a non-uniform heat sink provides more effective cooling than a heat source, and increasing the elastic
This document summarizes a numerical study of squeeze film dampers. Key points:
- Squeeze film dampers are used in turbomachinery to reduce vibration and improve stability by dissipating energy through viscous forces.
- A steady state solver was used to model the whirling motion of the rotor, allowing for more efficient computation compared to unsteady models.
- Results from simulations at 50Hz matched well with experimental pressure data, validating the steady state approach.
- Pressure and liquid fraction contours from the simulations showed the expected patterns, with high pressure before minimum clearance dropping rapidly afterward.
The document investigates the effects of adding ultra-dispersed diamond (UDD) nanoparticles to oil on the tribological and thermal properties of a piston ring-cylinder liner system. Experiments found that adding UDD at 0.02% and 0.10% mass fractions reduced friction, wear, and bulk temperature compared to pure oil. The UDD is believed to increase the surface bearing capacity, improving the tribological properties.
Probabilistic approach to study the hydroformed sheetIJERA Editor
Under the leadership of the Kyoto agreements on reducing emissions of greenhouse gases, the automotive sector was forced to review its methods and production technologies in order to meet the new environmental standards. In fuel consumption reduction is an immediate way to reduce the emission of polluting gases. In this paper, the study of the formability of sheet submitted to the hydroforming process is proposed. The numerical results are given to validate the proposed approach. To show the influence of uncertainties in the study process, we take some characteristics of the material as random and the probabilistic approach is done. The finding results are showing the effectiveness of the proposed approach.
Finite element simulation and investigation of thin wall impeller casting ija...Dr.Vikas Deulgaonkar
In case of casting of thin wall impeller structure, the prediction of shrinkage defect is a difficult operation and failure of such thin wall structure is a commonly encountered problem. Such failures are due to non-uniform heat transfer rate. The uniformity of heat transfer rate may enhance by placing the runner at appropriate position and riser based on the geometrical attributes. An attempt is made for the analysis of optimization in the placement of runner and riser. The present work focuses on the simulation of aluminum thin wall pump impeller blade using commercially available software (ANSYS) and experiments for optimum placement of risers and reducing defects.
Temperature Dependence of Density and Dynamic Surface Tension of Groundnut Oi...theijes
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.
This document summarizes the results of a study analyzing the mechanical behavior and limit load of a 12kg S235 steel gas bottle used for domestic gas. Experimental and numerical simulations were conducted. Experimental tests applied increasing internal pressure to a physical prototype bottle until failure, measuring displacement and strain. Finite element modeling using Patran and Nastran software simulated bottle behavior under pressure. Results showed good agreement between experimental maximum load, displacement and von Mises stress compared to numerical values. The study also modeled a 35kg gas bottle to analyze mechanical behavior without physical testing.
Bulk Density & Voids in Aggregate | Jameel AcademyJameel Academy
This report details tests conducted to determine the bulk density and voids of fine and coarse aggregates. Samples of fine and coarse aggregate were tested with and without compaction. For each test, the mass of the aggregate sample, mass of the container, and volume of the container were measured. The bulk density of each sample was then calculated using these values. The results showed that bulk density ranged from 1591.4-1919.1 kg/m3 for fine aggregate and 1746.1-1591.4 kg/m3 for coarse aggregate. Voids in the samples ranged from 26.7-31.3% for fine aggregate and 34.49-39.3% for coarse aggregate. In conclusion, the
Splashing mechanism during impact of a hollow droplet on a substrate(156)docamarjitkene
1) The document summarizes a numerical study comparing the splashing behavior of continuous and hollow molten droplets during impact on a substrate.
2) For continuous droplets, splashing occurs very early during spreading due to high spreading velocities creating instabilities at the edge, detaching satellite droplets that solidify and create barriers for further spreading.
3) In contrast, hollow droplets were found to experience significantly less splashing due to a new phenomenon of counter liquid jetting during flattening, which suppresses instabilities.
This document summarizes an industrial seminar on rheology presented by Modh Sudipkumar. It discusses the importance of rheology in industrial processes and its effect on product cost, stability, and recalls. It outlines different types of viscometers and rheometers used in industry and their applications in evaluating stability of formulations like suspensions, emulsions, and ointments. Newer instruments like interfacial shear rheometers and stress rheometers are able to characterize more complex fluid behaviors at interfaces and under varying stresses. Rheology is presented as a rapid screening method to test stability by monitoring changes in storage and loss modulus.
This document presents an analysis of free convective flow and heat transfer of a viscous incompressible fluid over a linearly moving vertical porous plate with suction and viscous dissipation. The fluid viscosity is assumed to vary linearly with temperature. Governing boundary layer equations are non-dimensionalized using similarity transformations and reduced to a boundary value problem. The problem is solved numerically using a shooting method along with the 4th order Runge-Kutta method. Results for dimensionless velocity and temperature distributions are presented for various parameter values, and skin friction and Nusselt numbers are reported in tables.
Influence of micropolar lubricant on bearings performance a review(2)susheelpote
This review article summarizes research on the influence of micropolar lubricants on bearing performance. Micropolar lubricants account for the microstructural effects of additives and contaminants in lubricating oils. The article first introduces micropolar fluid theory, which generalizes the Navier-Stokes equations to include microrotation effects. It then reviews how micropolar theory has been applied to analyze the performance of various bearing configurations, including slider, thrust, step slider, and journal bearings. The performance metrics considered include load capacity, friction, flow, heat generation, and stability. Research has found micropolar lubricants can increase load capacity and reduce friction in many bearing types compared to classical Newtonian lubric
The impact of the diameter to height ratio on the compressibility parameters ...eSAT Journals
Abstract Compressibility parameters of fine-grained soils are mainly influenced by soil mineralogy, moisture content and soil diameter to height ratio (D/H). The British and American standards suggested that to obtain accurate engineering properties; it is necessary to use D/H ratio of 4 and 2.5 respectively to eliminate friction between the soil and the structure. In the current study, various D/H ratios were adopted ranging from 0.5 to 11. The D/H ratios effect on some compressibility parameters such as coefficient of consolidation (cv), compression index (cc) and coefficient of volume compressibility (mv) were analysed. Additionally, the impact of the D/H ratio on the acquire cv values were also presented where three methods were used namely: Casagrande, Taylor and Inflection method. The scaling effects based on cv ratio [cv (√t) / cv (log t)] from Oedometer tests using different D/H ratios are also presented. The results showed that Taylor’s method is the most appropriate way to achieve an accurate cv and an increase in pressure leads to a reduction in cc and a gradual decrease in mv. The validation of the experimental results on a finite element software package PLAXIS was completed. Keywords: Compressibility, D/H ratio, Fine-grained soil, Friction
Non-Newtonian Visco-elastic Heat Transfer Flow Past a Stretching Sheet with C...IJERA Editor
In this paper two dimensional flow of a viscoelastic fluid due to stretching surface is considered. Flow analysis is carried out by using closed form solution of fourth order differential equation of motion of viscoelastic fluid. Further (Walters’ liquid B’ model) heat transfer analysis is carried out using convective surface condition. The governing equations of flow and heat transfer are non-linear partial differential equations which are unable to solve analytically hence are solved using Runge-Kutta Numerical Method with efficient shooting technique. The flow and heat transfer characteristics are studied through plots drawn. Numerical values of Wall temperature are calculated and presented in the table and compared with earlier published results which are in good agreement
The Elastic-plastic Deformation Analysis of the Hydraulic Pipe under Equivale...IOSR Journals
The finite element model of an aircraft hydraulic pipe was established using the ANSYS APDL
command in this paper. The equivalent static pressures as surface loads were applied to the hydraulic pipe
based on LS-Dyna software. The pressures were measured in the tire burst test. The stress, strain contours and
time course curve of hydraulic pipe were obtained under the dynamic loads. The elastic-plastic deformations of
the hydraulic pipe were analyzed by Von Mises yield criterion. The maximum stress is 1090000KPa beyond the
yield limit. The hydraulic pipe occurred to plastic deformation. The maximum strain is 0.29168. It is not exceed the elongation of the material. The pipe does not break.
To Experimental Study of Comparison and Development of Design for Rigid Pavem...Agriculture Journal IJOEAR
Abstract— The development of design have been discussed adopted various types methods use. The Hadi and Arfiadi Method presents a formulation for the optimum rigid road pavement design by genetic algorithm, a new method. The Westergaard’s Method determines the stresses in the rigid concrete slab and also the pressure-deformation curve which depend upon the relative stiffness of the slab and the subgrade. Razouki and Al-Muhana also developed stress charts similar to Westergaard’s method. The paper reveals that the effects on the maximum bending tensile stress are quite significant due to the modulus of subgrade reaction, modulus of elasticity of concrete and slab The Maharaj and Gill method have performed axisymmetric finite element analysis by varying parameters, the thickness of pavement, pressure and elastic modulus of subgrade. The advantage of this method is that four types of design charts have been presented which other methods have note done. First type of design chart has been plotted between thickness of pavement and nodal deflections for various pressures for a particular elastic modulus of soil. Second type of design chart has been plotted between thickness of pavement and element stress for various pressures for a particular elastic modulus of soil. The third type of design chart has been plotted between thickness of pavement and nodal deflections for various elastic moduli of subgrade for a particular pressure. Each of the design charts has three parameters. For two known parameters, the third parameter can be obtained.
This document discusses the fundamentals of rheology and describes various types of rheometers used to measure the rheological properties of asphalt binders. It explains that rheology is the study of flow and deformation and introduces constitutive relationships between force and deformation. It then describes different types of rheometers, including shear rheometers that apply drag or pressure-driven flows, and other rheometers that measure stiffness and strength through bending beam or direct tension tests. Specific examples of equipment are also shown, such as concentric cylinder and parallel plate shear rheometers, a bending beam rheometer, and a direct tension testing device.
H-J Enterprises manufactures air to air bushings for voltages ranging from 15kV to 38kV. The document provides detailed specifications for standard and custom bushing assemblies, including dimensions, materials used, and electrical test results. H-J Enterprises also offers electrical testing of bushings, including basic impulse, partial discharge, and cantilever load testing to certify that bushings meet appropriate standards.
This document summarizes a research paper on using active power filters to reduce total harmonic distortion. It provides background on power quality issues caused by harmonics from nonlinear loads. Active power filters inject harmonic currents to cancel out load harmonics. The document describes shunt and series active power filters and their control methods. Simulation results show that a shunt active power filter can reduce the voltage THD from 17.92% to 11.46% and current THD from 0.53% to 0.46% for an AC-DC converter feeding an R-L load. Thus, active power filters are effective in mitigating harmonics and improving power quality.
The document discusses gesture-based computing as an alternative to mouse input for human-computer interaction. It proposes a novel approach for implementing a real-time gesture recognition system capable of understanding commands based on analyzing the principal contour and fingertips of hand gestures. Vision-based gesture recognition techniques are discussed that do not require additional devices for users to interact with computers through natural hand motions.
Experimental Method to Analyse Limit Load in Pressure VesselIJMER
Pressure vessel contains with different inlet & outlet openings called nozzle or valves. The design parameter of these valves may different in one pressure vessel. These valves cause geometric discontinuity of the pressure vessel wall hence stress concentration may occur around the valve or nozzle. Since due to the high stress concentration there may be the chances of failure of vessel junction. Hence detail stress distribution analysis needs to be done for pressure vessel. Determination of limit pressure at different location on pressure vessel by using finite element method is less time consuming
and it avoid complex mathematical work at difficult geometries. So, it is essential to validate the result.
Experiments is conducted on oblique nozzle (450 with shell axis) & result obtained are used to validate
the finite element results. Distortion measurement test by measuring change in diameter of vessel after
vessel is pressurized using water. Twice elastic slope method & Tangent intersection method are used to
find out limit load estimation of cylindrical vessel with oblique (450) nozzle.
Conical Fluidized Beds - Case Study for a Gas Solid System Involving Wheat Fl...IRJET Journal
This document summarizes a study on fluidization of wheat flour and additive particles in a conical fluidized bed. Key points:
- Conical fluidized beds can handle particles of varying sizes and cohesive particles better than traditional cylindrical beds due to varying gas velocity.
- An experiment was conducted using a two-dimensional conical bed with a 20.5° cone angle. Wheat flour and crushed wheat were used as particles.
- Pressure drop and fluidization properties were measured for beds containing various ratios of flour and crushed wheat additive. The study aimed to improve fluidization of cohesive flour using the crushed wheat additive.
Effect of non uniform heat source for the ucm fluid over a stretching sheet w...IAEME Publication
This document summarizes a study on the effect of a non-uniform heat source on fluid flow over a stretching sheet with an applied magnetic field. The fluid is modeled as an upper-convected Maxwell (UCM) fluid. Similarity transformations are used to reduce the governing non-linear partial differential equations to an ordinary differential equation, which is then solved numerically using a fourth-order Runge-Kutta method. Graphical results are presented showing the effects of various parameters like the elastic parameter, Eckert number, magnetic parameter, and non-uniform heat source on the velocity and temperature profiles. The key findings are that a non-uniform heat sink provides more effective cooling than a heat source, and increasing the elastic
This document summarizes a numerical study of squeeze film dampers. Key points:
- Squeeze film dampers are used in turbomachinery to reduce vibration and improve stability by dissipating energy through viscous forces.
- A steady state solver was used to model the whirling motion of the rotor, allowing for more efficient computation compared to unsteady models.
- Results from simulations at 50Hz matched well with experimental pressure data, validating the steady state approach.
- Pressure and liquid fraction contours from the simulations showed the expected patterns, with high pressure before minimum clearance dropping rapidly afterward.
The document investigates the effects of adding ultra-dispersed diamond (UDD) nanoparticles to oil on the tribological and thermal properties of a piston ring-cylinder liner system. Experiments found that adding UDD at 0.02% and 0.10% mass fractions reduced friction, wear, and bulk temperature compared to pure oil. The UDD is believed to increase the surface bearing capacity, improving the tribological properties.
Probabilistic approach to study the hydroformed sheetIJERA Editor
Under the leadership of the Kyoto agreements on reducing emissions of greenhouse gases, the automotive sector was forced to review its methods and production technologies in order to meet the new environmental standards. In fuel consumption reduction is an immediate way to reduce the emission of polluting gases. In this paper, the study of the formability of sheet submitted to the hydroforming process is proposed. The numerical results are given to validate the proposed approach. To show the influence of uncertainties in the study process, we take some characteristics of the material as random and the probabilistic approach is done. The finding results are showing the effectiveness of the proposed approach.
Finite element simulation and investigation of thin wall impeller casting ija...Dr.Vikas Deulgaonkar
In case of casting of thin wall impeller structure, the prediction of shrinkage defect is a difficult operation and failure of such thin wall structure is a commonly encountered problem. Such failures are due to non-uniform heat transfer rate. The uniformity of heat transfer rate may enhance by placing the runner at appropriate position and riser based on the geometrical attributes. An attempt is made for the analysis of optimization in the placement of runner and riser. The present work focuses on the simulation of aluminum thin wall pump impeller blade using commercially available software (ANSYS) and experiments for optimum placement of risers and reducing defects.
Temperature Dependence of Density and Dynamic Surface Tension of Groundnut Oi...theijes
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.
This document summarizes the results of a study analyzing the mechanical behavior and limit load of a 12kg S235 steel gas bottle used for domestic gas. Experimental and numerical simulations were conducted. Experimental tests applied increasing internal pressure to a physical prototype bottle until failure, measuring displacement and strain. Finite element modeling using Patran and Nastran software simulated bottle behavior under pressure. Results showed good agreement between experimental maximum load, displacement and von Mises stress compared to numerical values. The study also modeled a 35kg gas bottle to analyze mechanical behavior without physical testing.
Bulk Density & Voids in Aggregate | Jameel AcademyJameel Academy
This report details tests conducted to determine the bulk density and voids of fine and coarse aggregates. Samples of fine and coarse aggregate were tested with and without compaction. For each test, the mass of the aggregate sample, mass of the container, and volume of the container were measured. The bulk density of each sample was then calculated using these values. The results showed that bulk density ranged from 1591.4-1919.1 kg/m3 for fine aggregate and 1746.1-1591.4 kg/m3 for coarse aggregate. Voids in the samples ranged from 26.7-31.3% for fine aggregate and 34.49-39.3% for coarse aggregate. In conclusion, the
Splashing mechanism during impact of a hollow droplet on a substrate(156)docamarjitkene
1) The document summarizes a numerical study comparing the splashing behavior of continuous and hollow molten droplets during impact on a substrate.
2) For continuous droplets, splashing occurs very early during spreading due to high spreading velocities creating instabilities at the edge, detaching satellite droplets that solidify and create barriers for further spreading.
3) In contrast, hollow droplets were found to experience significantly less splashing due to a new phenomenon of counter liquid jetting during flattening, which suppresses instabilities.
This document summarizes an industrial seminar on rheology presented by Modh Sudipkumar. It discusses the importance of rheology in industrial processes and its effect on product cost, stability, and recalls. It outlines different types of viscometers and rheometers used in industry and their applications in evaluating stability of formulations like suspensions, emulsions, and ointments. Newer instruments like interfacial shear rheometers and stress rheometers are able to characterize more complex fluid behaviors at interfaces and under varying stresses. Rheology is presented as a rapid screening method to test stability by monitoring changes in storage and loss modulus.
This document presents an analysis of free convective flow and heat transfer of a viscous incompressible fluid over a linearly moving vertical porous plate with suction and viscous dissipation. The fluid viscosity is assumed to vary linearly with temperature. Governing boundary layer equations are non-dimensionalized using similarity transformations and reduced to a boundary value problem. The problem is solved numerically using a shooting method along with the 4th order Runge-Kutta method. Results for dimensionless velocity and temperature distributions are presented for various parameter values, and skin friction and Nusselt numbers are reported in tables.
Influence of micropolar lubricant on bearings performance a review(2)susheelpote
This review article summarizes research on the influence of micropolar lubricants on bearing performance. Micropolar lubricants account for the microstructural effects of additives and contaminants in lubricating oils. The article first introduces micropolar fluid theory, which generalizes the Navier-Stokes equations to include microrotation effects. It then reviews how micropolar theory has been applied to analyze the performance of various bearing configurations, including slider, thrust, step slider, and journal bearings. The performance metrics considered include load capacity, friction, flow, heat generation, and stability. Research has found micropolar lubricants can increase load capacity and reduce friction in many bearing types compared to classical Newtonian lubric
The impact of the diameter to height ratio on the compressibility parameters ...eSAT Journals
Abstract Compressibility parameters of fine-grained soils are mainly influenced by soil mineralogy, moisture content and soil diameter to height ratio (D/H). The British and American standards suggested that to obtain accurate engineering properties; it is necessary to use D/H ratio of 4 and 2.5 respectively to eliminate friction between the soil and the structure. In the current study, various D/H ratios were adopted ranging from 0.5 to 11. The D/H ratios effect on some compressibility parameters such as coefficient of consolidation (cv), compression index (cc) and coefficient of volume compressibility (mv) were analysed. Additionally, the impact of the D/H ratio on the acquire cv values were also presented where three methods were used namely: Casagrande, Taylor and Inflection method. The scaling effects based on cv ratio [cv (√t) / cv (log t)] from Oedometer tests using different D/H ratios are also presented. The results showed that Taylor’s method is the most appropriate way to achieve an accurate cv and an increase in pressure leads to a reduction in cc and a gradual decrease in mv. The validation of the experimental results on a finite element software package PLAXIS was completed. Keywords: Compressibility, D/H ratio, Fine-grained soil, Friction
Non-Newtonian Visco-elastic Heat Transfer Flow Past a Stretching Sheet with C...IJERA Editor
In this paper two dimensional flow of a viscoelastic fluid due to stretching surface is considered. Flow analysis is carried out by using closed form solution of fourth order differential equation of motion of viscoelastic fluid. Further (Walters’ liquid B’ model) heat transfer analysis is carried out using convective surface condition. The governing equations of flow and heat transfer are non-linear partial differential equations which are unable to solve analytically hence are solved using Runge-Kutta Numerical Method with efficient shooting technique. The flow and heat transfer characteristics are studied through plots drawn. Numerical values of Wall temperature are calculated and presented in the table and compared with earlier published results which are in good agreement
The Elastic-plastic Deformation Analysis of the Hydraulic Pipe under Equivale...IOSR Journals
The finite element model of an aircraft hydraulic pipe was established using the ANSYS APDL
command in this paper. The equivalent static pressures as surface loads were applied to the hydraulic pipe
based on LS-Dyna software. The pressures were measured in the tire burst test. The stress, strain contours and
time course curve of hydraulic pipe were obtained under the dynamic loads. The elastic-plastic deformations of
the hydraulic pipe were analyzed by Von Mises yield criterion. The maximum stress is 1090000KPa beyond the
yield limit. The hydraulic pipe occurred to plastic deformation. The maximum strain is 0.29168. It is not exceed the elongation of the material. The pipe does not break.
To Experimental Study of Comparison and Development of Design for Rigid Pavem...Agriculture Journal IJOEAR
Abstract— The development of design have been discussed adopted various types methods use. The Hadi and Arfiadi Method presents a formulation for the optimum rigid road pavement design by genetic algorithm, a new method. The Westergaard’s Method determines the stresses in the rigid concrete slab and also the pressure-deformation curve which depend upon the relative stiffness of the slab and the subgrade. Razouki and Al-Muhana also developed stress charts similar to Westergaard’s method. The paper reveals that the effects on the maximum bending tensile stress are quite significant due to the modulus of subgrade reaction, modulus of elasticity of concrete and slab The Maharaj and Gill method have performed axisymmetric finite element analysis by varying parameters, the thickness of pavement, pressure and elastic modulus of subgrade. The advantage of this method is that four types of design charts have been presented which other methods have note done. First type of design chart has been plotted between thickness of pavement and nodal deflections for various pressures for a particular elastic modulus of soil. Second type of design chart has been plotted between thickness of pavement and element stress for various pressures for a particular elastic modulus of soil. The third type of design chart has been plotted between thickness of pavement and nodal deflections for various elastic moduli of subgrade for a particular pressure. Each of the design charts has three parameters. For two known parameters, the third parameter can be obtained.
This document discusses the fundamentals of rheology and describes various types of rheometers used to measure the rheological properties of asphalt binders. It explains that rheology is the study of flow and deformation and introduces constitutive relationships between force and deformation. It then describes different types of rheometers, including shear rheometers that apply drag or pressure-driven flows, and other rheometers that measure stiffness and strength through bending beam or direct tension tests. Specific examples of equipment are also shown, such as concentric cylinder and parallel plate shear rheometers, a bending beam rheometer, and a direct tension testing device.
H-J Enterprises manufactures air to air bushings for voltages ranging from 15kV to 38kV. The document provides detailed specifications for standard and custom bushing assemblies, including dimensions, materials used, and electrical test results. H-J Enterprises also offers electrical testing of bushings, including basic impulse, partial discharge, and cantilever load testing to certify that bushings meet appropriate standards.
This document summarizes a research paper on using active power filters to reduce total harmonic distortion. It provides background on power quality issues caused by harmonics from nonlinear loads. Active power filters inject harmonic currents to cancel out load harmonics. The document describes shunt and series active power filters and their control methods. Simulation results show that a shunt active power filter can reduce the voltage THD from 17.92% to 11.46% and current THD from 0.53% to 0.46% for an AC-DC converter feeding an R-L load. Thus, active power filters are effective in mitigating harmonics and improving power quality.
The document discusses gesture-based computing as an alternative to mouse input for human-computer interaction. It proposes a novel approach for implementing a real-time gesture recognition system capable of understanding commands based on analyzing the principal contour and fingertips of hand gestures. Vision-based gesture recognition techniques are discussed that do not require additional devices for users to interact with computers through natural hand motions.
This document proposes a hybrid optimization algorithm using ant colony optimization and particle swarm optimization to solve the multiobjective multicast routing problem in wireless sensor networks. The goal is to optimize two objectives simultaneously - end-to-end delay and total transmitted power. ACO and PSO are combined to find Pareto-optimal solutions efficiently. Simulation results show the algorithm can find near-optimal solutions for minimizing delay and power consumption when routing data from a source to multiple destinations in wireless sensor networks.
This document summarizes the results of a finite element analysis of vibration effects on an internal combustion engine exhaust valve. The analysis sought to determine the natural frequency of the valve at which resonance might occur. A 3D CAD model of the valve was created and meshed before applying boundary conditions and material properties in ANSYS finite element software. Vibration analysis identified 5 modes of vibration with increasing frequencies up to a maximum of 1511.3 Hz, deemed the natural frequency. While deformations were largest at intermediate frequencies, the analysis concluded that vibrations near the natural frequency could damage the valve. Therefore, reducing deformation through constraints and maintaining operation below the natural frequency were recommended.
The document provides 10 reasons why students should not write their master's dissertation on sexual violence in war. It discusses how focusing solely on this topic can narrow political focus, inspire voyeurism in researching trauma, invoke colonial stereotypes, provide an insufficient historical account, ignore ethical dilemmas, neglect perspectives and positionality, encourage singular narratives that reinforce binaries, promote a non-feminist standpoint, inspire problematic proximity or distance, and result in replication rather than new insights. It encourages focusing studies on broader topics of gender, violence and militarism instead of continually reproducing analyses of sexual violence in war.
This document proposes an Android application that uses Huffman encoding to compress SMS messages. It summarizes that Huffman coding assigns shorter code words to more frequently used symbols, allowing SMS text to be compressed. The application requires installation on both the sender and receiver's phones to decompress messages. Testing showed the technique achieved up to 89% compression, reducing the size of example SMS texts. The summary provides an overview of the key points about using Huffman coding for SMS compression and the proposed mobile application.
This document discusses using Poisson's equation to extract features from human actions represented as space-time shapes. It begins by introducing how human actions can be represented as 3D shapes formed by concatenating 2D silhouettes over time. It then discusses how solving Poisson's equation on these space-time shapes allows extracting useful features like local space-time saliency, orientation, and dynamics. These features capture properties of the pose and motion of body parts and are shown to be effective for tasks like action recognition and clustering. The method is fast, applicable in many scenarios, and robust to issues like occlusions and scale/viewpoint changes.
This document summarizes a numerical study that examines the effects of fin spacing, fin material, and jet velocity on the heat transfer performance of plate fin heat sinks cooled by impinging air jets. The study considers fin spacings of 2mm, 3mm, and 4mm, and fin materials of aluminum, copper, and steel. Jet velocities of 5m/s, 10m/s, and 15m/s are examined. The results show that heat transfer rate increases with decreasing fin spacing, higher thermal conductivity fin materials like copper, and increasing jet velocity. Copper fins achieved the highest heat transfer rates but are heavier and more expensive than aluminum. A fin spacing of 2mm with aluminum fins and a jet velocity of 15
This document describes the design of a voice touch screen display device for blind students. The device uses a resistive touch screen interfaced with an ARM processor to allow visually impaired users to interact with and access educational content stored on an SD card. When a user touches areas of the screen guided by pointers, the selected content is announced verbally via a speaker system. The touch inputs are processed by the ARM processor which retrieves the appropriate audio files from the SD card to provide a natural interface for blind children to access educational activities independently.
This document summarizes a research paper on identifying factors related to the adoption of green manufacturing practices among small and medium enterprises (SMEs) in India. It discusses how analytic hierarchy process was used to validate scales for measuring identified factors. The research established that green manufacturing relates to green product design, raw materials, processes, technology, packaging and packaging design. It also reviews prior literature on green manufacturing, identifying gaps such as a lack of empirical studies conducted in India.
This document summarizes an experimental investigation into the energy stored in a flywheel motor system with multiple human operators. The study developed an experimental setup using elliptical and circular chainwheels connected to flywheels of varying mass. Trials were conducted with male riders of different weights and ages, measuring the revolutions and calculated energy stored for various gear ratios, flywheel masses, chainwheel types, rider weights and ages. The results showed that energy storage increased with rider weight up to 70kg, and was highest for riders aged 25-30 years. Elliptical chainwheels stored approximately 13% more energy than circular chainwheels. The study aims to optimize the performance of human-powered flywheel systems.
This document summarizes a research paper that compares different digital filtering techniques for removing noise from electrocardiogram (ECG) signals. It describes how finite impulse response (FIR) filters were designed using various windowing techniques, including rectangular, Hamming, Hanning, and Blackman windows. Infinite impulse response (IIR) filters and wavelet transforms were also evaluated for denoising ECG signals. The performance of the different filtering approaches were compared based on the power spectral density and average power of the signals before and after filtering. The paper found that an FIR filter designed with the Kaiser window showed the best results for noise removal from ECG signals.
The document discusses the benefits of meditation for reducing stress and anxiety. Regular meditation practice can help calm the mind and body by lowering heart rate and blood pressure. Making meditation a part of a daily routine, even if just 10-15 minutes per day, can have mental and physical health benefits over time by helping people feel more relaxed and better able to handle life's stresses.
This document summarizes and compares different channel estimation techniques for OFDM systems. It discusses block-type pilot arrangement where pilots are sent on all subcarriers periodically, and comb-type pilot arrangement where pilots are spaced between data symbols. For block-type, channel estimation can be done with LS or MMSE. For comb-type, estimation is done at pilot frequencies using LS, MMSE or LMS, and interpolation between pilots with techniques like linear, cubic spline. Decision feedback equalizer is also implemented for block-type. Performance is evaluated using modulation schemes like QPSK, 16QAM under fading channels, and comb-type is shown to track fast fading better than block-type.
1) The document presents an integrated technique for detecting brain tumors in MRI images that combines modified texture-based region growing segmentation and edge detection.
2) The technique first performs pre-processing on MRI images, then uses modified texture-based region growing to segment regions. It then applies edge detection to extract the tumor region.
3) Experimental results show the integrated technique provides more accurate tumor detection compared to individual segmentation methods and manual segmentation.
This document discusses various techniques for image contrast enhancement, including contrast stretching, grey level slicing, histogram equalization, local enhancement equalization, image subtraction, and spatial filtering. It provides details on how each technique works and compares their performance both qualitatively and quantitatively using metrics like SNR and PSNR. The conclusion is that contrast stretching generally provides the best enhancement among the techniques compared, but other techniques may be better suited for specific applications.
This document contains facts about Rachael H. and Ukraine. It provides biographical details about Rachael, such as where she is from, her major, and hobbies. Regarding Ukraine, it notes that the country gained independence in 1991 from the Soviet Union and experienced political and economic turmoil following this. It also discusses issues Ukraine has faced with human trafficking after independence and how Ukrainian women are particularly vulnerable to being trafficked.
This document summarizes a study comparing the design of an industrial building using a pre-engineered building (PEB) concept versus a conventional steel building (CSB) concept. The building was designed for both concepts using structural analysis software, with wind loads as the critical design factor. The results showed that PEBs are advantageous over CSBs due to the ability of PEBs to use optimally tapered sections tailored for bending moment requirements, saving on excess steel and reducing costs compared to the standard sections used in CSBs.
This document summarizes a research paper that proposes using NFC (Near Field Communication) technology and Android applications to develop an identification and hospital management system. NFC tags would be placed on patient wristbands and doctor badges to uniquely identify individuals. When an NFC-enabled mobile device is held near a tag, the unique ID is transmitted and patient/doctor records can be automatically accessed from a backend server. This allows for contactless identification, retrieval of medical records, and updating of patient information during rounds. The proposed system aims to streamline workflows and reduce manual paperwork. It was tested successfully between NFC tags, Android applications and a backend server database.
The document describes a multiphysics model for simulating the performance of spring-supported thrust bearings used in hydropower applications. The model couples the Reynolds lubrication equation, solid mechanics, and heat transfer to account for pressure distribution, elastic deformation, and temperature effects. It was implemented in COMSOL Multiphysics and can predict key outputs like film thickness, temperature, and the effects of varying operating parameters and materials. The results demonstrate the model's capability to provide insights into thrust bearing behavior and facilitate their design and analysis.
THERMOHYDRODYNAMIC ANALYSIS OF PLAIN JOURNAL BEARING WITH MODIFIED VISCOSITY ...IAEME Publication
The purpose of this paper is to predict the temperature distribution in fluid-film, bush housing and journal along with pressure in fluid-film using a non-dimensional viscosity-temperature equation. There are two main governing equations as, the Reynolds equation for the pressure
distribution and the energy equation for the temperature distribution. These governing equations are coupled with each other through the viscosity. The viscosity decreases as temperature increases. The hydrodynamic pressure field was obtained through the solution of the Generalized Reynolds
equation. This equation was solved numerically by using finite element method.
Analysis of Heat Generation in Double Pipe Heat Exchanger: An Experimental Ev...IRJET Journal
This document summarizes research on analyzing heat generation in a double pipe heat exchanger with an elliptical fin surface contact. An experiment was conducted to compare the heat transfer rate of an elliptical fin to other fin types (tube-tube, rectangular, annular, spiral rod). The results showed the elliptical fin had a higher heat transfer rate. The document reviews several other studies analyzing different fin geometries, heat transfer optimization techniques, and computational fluid dynamics simulations of heat exchangers. It provides background on analyzing heat exchangers using methods like logarithmic mean temperature difference and effectiveness-NTU and discusses prior work optimizing dimensions, materials, and flow conditions to improve heat transfer performance.
Temperature Rise of Double-Row Tapered Roller Bearings Analyzed with a Therma...Siyuan Ai
This document presents a thermal network model to analyze temperature rise in double-row tapered roller bearings lubricated with grease. The model is based on generalized Ohm's law and considers friction losses and drag viscous losses. A quasi-static model is used to determine load distribution and kinematic parameters. The model then analyzes how temperature rises at different speeds, grease filling ratios, and roller geometries. Results show high temperatures occur at high speeds and grease ratios, especially at roller end/flange contacts. An optimal roller geometry is also identified.
Design and analysis of disc brake rotor for a two wheelerVenkat Swaroop
This document summarizes a study that performed finite element analysis of the thermo-elastic behavior of disc brake rotors. The study analyzed the temperature distribution and stress patterns in three different materials for a disc brake rotor undergoing repeated braking conditions. The results validated that the transient thermal and structural analysis converged with the steady state solution over a 10 second braking period. The maximum temperatures achieved in the rotor and the conclusions drawn regarding the three materials are presented in the tables and figures.
This document summarizes a journal article that investigates the effects of reverse textures on the bearing surface of a journal bearing using computational fluid dynamics (CFD). The study extends prior work by adding reverse dimples in the form of metal additions to the bearing surface rather than just cylindrical dimples. The CFD model is validated by comparing results for load capacity and friction coefficient to a previous study. Load capacity, friction force, and friction coefficient are calculated to evaluate the performance of the textured bearing design versus a smooth surface.
Gas foil bearing analysis and the effect of bump foil thickness on its perfor...ijmech
Gas foil bearings (GFBs) satisfy many of the requirements noted for novel oil-free turbomachinery.However, GFBs have a limited load carrying capacity. This paper presents a numerical model in order to assess the performance characteristics of gas foil bearings. The finite difference scheme has been used to discretize the governing Reynolds equation and the pressure is calculated by solving non-linear matrix equation using Newton-Raphson technique. The static performance analysis has been carried out. The computational analysis have been compared with the experimental and theoretical results available in the literature and the effects of bump foil thickness, number of bumps and bump compliance coefficient on the load carrying capacity at different rotor speed have been investigated. The results of the study show that too thin bump foil thickness may lead to a significant decrease in the load capacity. However for accurate predictions of the foil bearing performances, more details foil structure of 1D and 2D finite element model
should be considered.
Numerical Analysis of Hygrothermal Effect on Laminated Composite PlatesIRJET Journal
This document presents a numerical analysis of the hygrothermal effects on laminated composite plates. It summarizes previous research on modeling the behavior of composite laminates under temperature and moisture gradients. The analysis uses the finite element tool ABAQUS to model simply supported cross-ply laminates and compare the displacement and stress results to analytical solutions. The numerical model considers shear deformation and transverse thermal strains and predicts the hygrothermal response of symmetric and antisymmetric angle-ply plates with different layer orientations and material properties.
This document summarizes an experimental investigation into the effect of turbine phantom cooling on the suction side of a nozzle guide vane. Phantom cooling refers to coolant injected from the endwall that moves toward the airfoil suction side, providing a secondary cooling effect. The study uses pressure sensitive paint to measure film cooling effectiveness on a scale model turbine vane under different blowing ratios and incidence angles. It finds that incidence angle can alter the direction of coolant jets on the pressure side and change film cooling effectiveness distributions on the airfoil suction side.
Experimental Analysis and Investigation for Thermal Behaviour of Ventilated D...ijsrd.com
In the present review, we discuss works that have been published in the last 15 – 20 years that are based on the computational and experimental analysis of thermal properties of disc brake rotor of various types; new applications of the theory of heat conduction, convection and radiation. As the rapid development of computer engineering have led to a considerable increase in the number of solvable problems, and the refining of mathematical methods and approaches enables one to construct analytic solutions of these problems. In the paper, we outline the main directions of investigation of the processes of interaction of bodies with regard for heat release. We describe computational methods in more detail as compared with other approaches, because, to our mind, they are very promising for deriving simple engineering relations for braking processes on the basis of the equations of the thermal dynamics of friction; also the actual braking system is much transient and a lot of variable changes at a time which becomes very difficult to calculate experimentally.
1. The document discusses an experimental study on the effect of leading edge fillet geometry on endwall film cooling effectiveness for a first-stage turbine vane. Three types of sharp slope fillets with different length-to-height ratios were tested and compared to a baseline geometry without a fillet.
2. Film cooling effectiveness distributions were obtained using pressure sensitive paint. Results showed that film cooling effectiveness increased with increasing blowing ratio. The baseline geometry provided the best film cooling near the leading edge pressure side. The effect of leading edge geometry on the suction side depended on the blowing ratio.
3. Previous literature has found that leading edge modifications can control the horseshoe vortex and secondary flows and thereby impact film cooling effectiveness
Evaluation of Air Flow Characteristics of Aerostatic Thrust Porous Bearings: A Numerical Approach by Marcelo Gustavo Coelho Resende, Leandro José da Silva, Cláudio de Castro Pellegrini and Túlio Hallak Panzera* in Evolutions in Mechanical Engineering: Crimson Publishers_ Structural engineering
Aerostatic porous bearings have been investigated in the last decades for precision engineering designs, since these bearings offer zero-friction and high operating speeds, as well as providing a very precise positioning system without external influence. Numerical methods such as CFD (Computational Fluid Dynamics) play an important role in the design and behavior analysis of porous aerostatic bearings, being possible to adjust the geometry and characteristics of the porous restrictor even before its manufacture In the present work, the behavior of the gas at the inlet and outlet of a porous thrust bearing made of cementitious composites is analysed by numerical simulation using CFD method. The results reveal a stable behavior of the cementitious porous bearing and a good correlation between numerical and experimental load capacities.
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Assessment of Performance Characteristic of Solar Air Heater with Assorted Ge...IJERA Editor
Artificial roughness is an efficient way for increasing the heat transfer rate in solar air heater with the
corresponding improvement in its thermal performance. A viscous sub-layer is responsible for the low heat
transfer coefficient between absorber plate and flowing air. Repeated ribs in form of artificial roughness are an
effective way to increase the heat transfer rate and improving the performance of solar air heater. Artificial
roughness of the absorber plate is much economical and effective way to improve the thermal performance of
solar air heater. Several investigators have done various investigations to improve heat transfer coefficient with
little penalty of friction factor. They have also developed different correlation for heat transfer coefficient and
friction factor. The correlations developed for heat transfer and friction factor by various investigators have been
reviewed and presented.
Assessment of Performance Characteristic of Solar Air Heater with Assorted Ge...IJERA Editor
Artificial roughness is an efficient way for increasing the heat transfer rate in solar air heater with the
corresponding improvement in its thermal performance. A viscous sub-layer is responsible for the low heat
transfer coefficient between absorber plate and flowing air. Repeated ribs in form of artificial roughness are an
effective way to increase the heat transfer rate and improving the performance of solar air heater. Artificial
roughness of the absorber plate is much economical and effective way to improve the thermal performance of
solar air heater. Several investigators have done various investigations to improve heat transfer coefficient with
little penalty of friction factor. They have also developed different correlation for heat transfer coefficient and
friction factor. The correlations developed for heat transfer and friction factor by various investigators have been
reviewed and presented.
Structural Changes in the Surface Layer of Deep Rolled Samples Due to Thermal...IJERA Editor
Deep rolling processes initiate plastic deformations in the surface layer. The local characteristics of deformation are dependent on the induced stress expressed by the local stress tensor. Equivalent stresses above yield strength cause plastic deformation. Additionally the intrinsic energy, e. g. the dislocation density, is enhanced and the residual stress state is changed. The effects to a deep rolled surface from an increase in temperature are mainly dependent on the material, the microstructure, the initial residual stress state, the inclusion density, the distribution of soluted alloying elements and the plastic deformation. In the described experiments the interactions between deformation and temperature of the steel grade AISI 4140 (42 CrMo 4) used for all further experiments in a transregional Collaborative Research Center (CRC) were to be examined. The most simple investigation methods were chosen deliberately to allow a better statistical support of correlations between introduced strains and material reactions for a wide variation of process parameters. Since the visual effects by light microscopy in AISI 4140 were very small, the experiments were repeated with german grade 18 CrNiMo 7-6 (comparable to AISI 4820). This paper focuses on the micro structural changes in defined deep rolled surface regions due to an increase in temperature. The work described is part of the Collaborative Research Center “Process Signatures”, collaboration between Bremen University, Technical University Aachen, Germany and Oklahoma State University Stillwater, USA.
Wear Rate Analysis of Hydrodynamic Journal Bearing In Different ConditionsIJMER
Friction and wear always occur at machine parts which run together. This affects the
efficiency of machines negatively. Hydrodynamic journal bearings are widely used in industry because
of their simplicity, efficiency and low cost. Wear due to relative motion between component surfaces is
one of the primary modes of failure for many engineered systems. Unfortunately, it is difficult to
accurately predict component life due to wear as reported wear rates generally exhibit large scatter.
An attempt has been made to study the influence of wear parameters like load, speed, type of lubricant
used, temperature, and viscosity of lubricant. The main objective of the study is to evaluate the wear
rate of different journalbearing materials (brass and white metal) under similar conditions. The
materials are tested in dry and wet lubrication under similar operating conditions. For this purpose we
use Pin-on-disc apparatus. It was found that the wear rate of both materials is more in dry conditions
compared to lubricated conditions (when tested under similar working conditions). We also found that
wear rate of white metal is more as compared to brass and higher frictional force is observed in case
of brass material
This document summarizes an experimental investigation into the effects of trailing edge discharge cooling on the film cooling effectiveness of a turbine nozzle guide vane endwall. The study uses pressure sensitive paint to measure film cooling effectiveness on an endwall downstream of turbine blade trailing edges with discharge holes at compound angles. It examines the interaction between coolant from the endwall and trailing edge, referred to as "phantom cooling", and how blowing ratio and compound angle configuration affect film cooling performance. The experiments were conducted on a scale model turbine nozzle guide vane cascade with Reynolds number of 3.5×105 and inlet Mach number of 0.1 while varying the blowing ratio from 0.7 to 1.3 and compound angle of the trailing edge holes.
Performance Analysis and Comparison of Journal Bearing using Ferro Fluid & Ma...ijsrd.com
Now days the works are focuses on Smart fluid technology which is an emerging field of research and that has lead to the introduction of Ferro fluids, they are smart materials whose rheological properties (viscosity, yield stress, shear modulus etc.) can be readily controlled on appliance of an magnetic field. Recent studies show that there is an increasing interest in designing hydro dynamically lubricated bearings using electro-rheological fluids (ERFs) or magneto rheological fluids (MRFs). Both smart fluids behave like Bingham fluids, and thus the Bingham plastic model is used to describe the grease and the electro-rheological (ER) and magneto-rheological (MR) fluids behavior of the non-Newtonian fluid flow. This work is concerned with the Computational fluid Dynamics of the hydrodynamic journal bearings lubricated with Ferro fluid and comparison of magneto rheological fluid. .. The solution renders the bearing performance characteristics, namely, load carrying capacity, attitude angle, frictional force at the journal surface, friction Coefficient and bearing side leakage. Ferro fluids can solve many difficult sealing, lubricating, detection, heat transfer and damping problems. Design of smart journal-bearing systems is an important issue that opens up the possibility for semi active dynamic control of bearing behavior using smart fluid technology.
The Analysis and Modification of SPUR Gear Designijsrd.com
This application are explain the design the spur gear and dimension specification. Its have a involving morden design, specific character, specific materials, with consideration of analysis of force, and its mechanical properties. These approach for morden spur gear design developing the tooth profils with modified the shape and improving the dimension. The main purpose of morden sper gear design it increases the power transmitting capacity and also improves the efficiency of power transmission.
IRJET- Jet Impingement Heat Transfer – A ReviewIRJET Journal
This document reviews research on jet impingement heat transfer. Jet impingement involves directing a jet of fluid at a surface and is an effective method for transferring heat. It has various industrial applications like cooling electronics and turbine blades. The review examines factors that influence heat transfer like jet geometry, cross flow effects, and frequency. It summarizes studies on single and multiple jet impingement, and the effects of parameters like Reynolds number. Conjugate heat transfer involving solid-fluid interaction is also discussed. The review provides an overview of research conducted on jet impingement heat transfer.
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.
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Paper id 27201419
1. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
46
Circular Bearing Performance Parameters with
Isothermal and Thermo-Hydrodynamic Approach Using
Computational Fluid Dynamics
Amit Chauhan1
Department of Mechanical Engineering,
University Institute of Engineering and Technology, Panjab University,
Chandigarh, India
Email: drchauhan98@gmail.com1
Abstract- The current work aims on the prediction of the effect of journal speed on the pressure and
temperature distribution in the circular journal bearing. The model has been simulated using the ANSYS Fluent
Software which solves 3-Dimensional Navier Stokes and Energy equation for finding the thermal performance
characteristics of the bearing. The lubricant flow has been considered as laminar. The distribution of pressure
and temperature throughout the bearing has been obtained by iso-thermal approach and by thermo-hydrodynamic
approach. The clearance space for the lubricant film between the journal and bearing surface has
been considered as 200 microns. The analysis has been carried out at eccentricity = 0.8 and with speed of
journal varying from 2500 rpm to 5500 rpm. It has been observed that the rise in temperature is less in thermo-hydrodynamic
analysis as compared to iso-thermal analysis at all the journal speed because of the consideration
of viscosity variation along the temperature. Also the pressure, temperature and oil force rises with the increase
in the journal speed both in case of iso-thermal and thermo-hydrodynamic analysis.
Index Terms- Circular journal bearin;, ANSYS; iso-thermal; thermo-hydrodynamic.
1. INTRODUCTION
Hydrodynamic Journal Bearing is used to support the
rotating shaft extensively in high speed machinery,
example turbines, electric motors etc. Circular bearing
is the most commonly used profile of these bearings.
These bearing support the external load and the
presence of thick film of lubricant between the
clearance spaces avoid the metal contact of rotating
part of machinery with the surface of bearing. During
operation of the bearing, due to high journal speed,
the variation in temperature along the lubricant film
significantly affects the properties of the lubricating
oil. Hence it affects the performance of the bearing as
the lubricating oil inside the bearing depends upon the
pressure and the temperature. The increase in the
temperature of the oil film causes the breakage in the
layers of the lubricating film which consequently
leads to metal contact between the bearing and journal
surface. Here, the lubricant film between the journal
and the bearing is responsible for low friction and
high load carrying capacity of such bearings. The
variation in temperature and pressure of lubricant in
journal bearings affects the performance of the
bearing. Therefore the investigation of bearing
performance based on a thermo-hydrodynamic (THD)
analysis requires simultaneous solution of the
complex equations of flow of lubricant, Reynolds
Equation and the energy equation by consideration of
conduction and convention effect of the fluid domain.
Previously, the researchers investigate the
performance of the lubricant by solving the complex
equations through Finite Difference Method. With the
progress of analysis softwares, many researchers use
commercial computational fluid dynamics (CFD)
software to solve this complex equation. CFD codes
provides a solution to flow problems by solving the
full Navier-Stokes equations instead of Reynold's
Equation. Moreover, the CFD packages are applicable
to the complex geometries to solve the complex
simultaneous governing equations. The most of the
researches does the THD analysis by solving the
Reynolds and Energy equation only in the two
dimensions by neglecting the variation of pressure
and temperature across the film thickness. CFD
software solves these equations in three dimensions
by considering its variation along film thickness also.
First a remarkable work on Thermo-hydrodynamic
study of journal bearing was done by Hughes and
Osterle [1]. The authors have found out a relation
between viscosity as a function of temperature and
pressure of the lubricant inside the journal bearing for
adiabatic conditions. The authors have presented a
numerical example to illustrate the method. Gertzos et
al. [2] have investigated journal bearing performance
with a Non-Newtonian fluid i.e. Bingham fluid
considering the thermal effect. Chauhan et al. [3] have
presented a comparative study on the thermal
2. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
47
characteristics of elliptical and offset-halves journal
bearings. It has been reported by the authors that the
offset-halves bearing run cooler when compared with
elliptical bearing with minimum power loss and good
load capacity. Ouadoud et al. [4] have considered two
numerical methods, the finite volume is used to
determine the pressure, temperature and velocity
distributions in the fluid film, the displacement field
radial is obtained by the finite element method
respectively by using numerical simulation,
Computational Fluid Dynamic ”CFD” and Fluid
Structure Interaction ”FSI”. The authors have
analyzed the influence of the operating conditions on
the pressure, temperature and displacement. Cupillard
et al. [5] presented an analysis of a lubricated
conformal contact to study the effect of surface
texture on bearing friction and load carrying capacity
using computational fluid dynamics. The work mainly
concentrates on a journal bearing with several
dimples. The authors have reported that the
coefficient of friction can be reduced if a texture of
suitable geometry is introduced and the same can be
achieved either in the region of maximum
hydrodynamic pressure for a bearing with high
eccentricity ratio or just downstream of the maximum
film for a bearing with low eccentricity ratio. Sahu et
al. [6] have carried out THD analysis of a journal
bearing as a tool. The authors have presented 2-
dimensional distribution and 3-dimensional pressure
of the lubricating film. Basri and Gethin [7] have
investigated the thermal aspects of various non-circular
journal bearings using adiabatic model.
Hussain et al. [8] presented a work is on the
prediction of temperature distribution in noncircular
journal bearings: two-lobe, elliptical and orthogonally
displaced bearings. The authors have presented results
for these geometries including the conventional
circular bearing. Liu et al. [9] have used
computational fluid dynamics and fluid structure
interaction method to study rotor-bearing system. The
authors have investigated the dynamic response of the
system with both the rigid and flexible bodies and
made a assumption of isothermal behaviour for all the
models. Further, the author have considered the
cavitation within the fluid film and reported that the
elastic deformation and dynamic unbalanced loading
of the rotor have significant effects on the position of
its locus. Li et al. [10] have presented a new method
for studying the 3D transient flow of misaligned
journal bearings in a flexible rotor-bearing system.
The results presented by the author indicate that the
bearing performances are greatly affected by
misalignment and method presented by them can
effectively predict the transient flow filed of the
system under consideration. Panday et al. [11] have
done the numerical unsteady analysis of thin film
journal bearing using ANSYS fluent software and
calculated the various bearing parameters like
pressure distribution, wall shear stress at different
eccentricities ratios.
Still the correlation of thermo-hydrodynamic
analysis and FSI is incomplete. Also the effect of
thermal analysis on the pressure distribution is
reported by few of the researchers using CFD as a tool
but the variation of temperature has not been
analyzed. An effort has been made to analyze the
thermohydrodynamic effect on variation of
temperature in the lubricant of the journal bearing.
2. GOVERNING EQUATIONS
2.1. Journal Bearing Geometry
The journal which rotates inside the bearing generates
the relative rotational velocity with each other. At
stable position, the journal takes an eccentric position
with respect to bearing. The amount of eccentricity is
adjusted by the generated pressure inside the
converging oil film balances the external load.
O
b
OJ
Rb
Rj
Ø
Fig. 1 Schematic diagram of circular journal bearing
Fig.1. represents the schematic diagram of circular
journal bearing. It has been clear that the generation
of pressure inside the journal bearing depends on the
eccentricity, the viscosity of the lubricant, bearing
internal surface geometry and the clearance space
between the journal and the bearing. The pressure in
the lubricant film depends upon the film thickness.
The equation for calculation of film thickness for a
circular journal bearing can be written as [4]:
h(q ) = C +ecosq =C(1+e cosq ) (1)
3. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
48
where,C represents the radial clearance space
between journal and bearing. ε represent the
eccentricity ratio of the journal bearing. θ gives the
value of film thickness along the circumferential
direction, being measured from the maximum film
thickness.
2.2. Navier Stokes Equation
The basic lubrication theory is based on the solution
of a particular form of Navier-Stokes equations as
described below. In this work the viscosity is kept
constant and the pressure obtained is called isothermal
pressure whereas when temperature dependent
viscosity is taken into consideration, then the pressure
obtained is called thermal pressure. Similarly same
convention is followed in the case of temperature [4].
r ¶ = - ¶ + h +
¶ ¶
( ) Mx
u p
div grad u S
t x
r ¶ = - ¶ + h +
¶ ¶
( ) My
v p
div grad v S
t y
r ¶ w = - ¶ p
+ div ( h grad w ) +
S
¶ t ¶ z
Mz
(2)
2.3. Energy Equation
The energy equation in mechanics of viscous thin
films is a particular form of shape differs from an
author to another depending on changes made to it.
The energy equation written for an incompressible
Newtonian fluid and the simplified calculation
domain is as follows [4]
(3)
where, QV represents volumetric heat source; CP
and K represents the Specific heat and thermal
conductivity of the lubricant respectively.
2.4. Thermo-hydrodynamic Consideration
The effect of temperature is considered on the
properties of the lubricating oil for calculation of
bearing parameters. For this User Defined Function
code is developed in the ANSYS software. By this
method a governing function is coded which would
control the variation of property of the fluid with
respect to pressure or temperature or both. The
following relation has been used for the variation of
viscosity as a function of pressure and temperature.
This equation has been adapted from the reference [1]
m = m ea ( p - p 0 ) eb ( t - t 0 )
0
(4)
where, a is the Barrus viscosity pressure index
constant and b is the temperature viscosity index
constant.
3. COMPUTATIONAL PROCEDURE
CFD package of ANSYS Fluent software has been
used to solve the Navier Stokes equation. Three
dimensional simulation model of circular journal
bearing has been developed by modeling the fluid
domain available between the journal and the bearing
surface. The clearance for the lubricant to support the
shaft between journal and bearing surface has been
considered as 200 microns. The eccentricity ratio is
taken as 0.8 with attitude angle of 56°. The
dimensions of the plain journal bearing used in this
simulation along with the lubricant properties are
given in the Table 1. The analysis has been carried out
at different journal speed varying from 2500 to 5500
rpm.
Table 1 : Operating Parameters
Shaft radius 50 mm
Internal bush radius 50.2 mm
Bearing length 100 mm
Lubricant density 850 Kg/m3
Specific heat of the lubricant 2000 J/Kg oC
Thermal conductivity of
0.13 W/m oC
lubricant
Convective heat transfer
coefficient
100 W/m2oC
Clearance 0.2 mm
Inlet lubricant temperature 30 oC
Rotational Speed
2500 to 5500
rpm
Initial viscosity 0.04986 Ns/m2
Pressure Viscosity Index (a) 2.3 e–8
Temperature Viscosity Index (b) 0.034
The steady state condition has been assumed. The
fluid flow is considered as laminar. The equations
have been solved without assuming the body forces.
A constant load has been assumed to be applied on the
journal surface. For meshing, a hexahedral structure
mesh is used. Name selection for various boundaries
like fixed wall for bearing surface and moving wall
for journal surface is done in ANSYS Meshing.
SIMPLE algorithm is chosen for the solution of
velocity pressure coupling equation. A first order
upwind scheme is used for the solution of energy and
momentum equation. Gravity forces have been
considered on the journal bearing and axis of rotation
4. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
49
has been taken at the eccentricity value of the journal.
The convergence criteria of 10-6 have been used for all
the residual terms.
4. RESULTS AND DISCUSSION
The bearing performance parameters have been
carried out by two different approaches. In the first
approach, the viscosity of the lubricant has been
considered as constant. This approach is named as
Iso-thermal approach that is there would not be any
change in the viscosity of the lubricant due to pressure
and temperature rise inside the oil film. In second
(A) Iso-thermal Analysis (B) Thermo-hydrodynamic Analysis
approach, the viscosity of lubricant is varying. This
approach is named as thermo-hydrodynamic approach
as the viscosity of the lubricant varies as the function
of pressure and temperature
The pressure distribution curve along the
circumference of circular bearing at 3500 rpm has
been shown in Fig. 2. It has been observed that the
maximum pressure rise in Iso-thermal analysis is
9.962 MPa while 6.653 M Pa was observed in case of
thermo-hydrodynamic Analysis. The variation of
maximum pressure built in the oil film with different
journal speed ranging from 2500 rpm to 5500 rpm has
been plotted in Fig. 3. It has been observed from the
graph that there was steep rise in pressure during iso-thermal
analysis as compared to thermal analysis
Fig. 2. Comparison of Pressure Distribution Profile for Isothermal and thermo-hydrodynamic analysis at journal
speed = 3500 rpm
Fig. 3. Variation of oil film pressure with the increase in journal speed from 2500 rpm to 5500 rpm for iso-thermal
and thermal analysis
5. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
50
Fig. 4 represents the temperature of the lubricant
film along the periphery of circular journal bearing at
eccentricity = 0.8 with journal speed = 5500 rpm. The
maximum rise in temperature of the oil film has been
observed as 95K in case of iso-thermal analysis but
the maximum temperature rise has been observed as
only 45 K in thermal analysis. The variation of
maximum temperature rise in the oil film with
different journal speed ranging from 2500 rpm to
5500 rpm has been plotted in Fig. 5. During Iso-thermal
analysis, the rise in temperature has been
occurred from 29 K to 95 K when journal speed
increases from from 2500 rpm to 5500 rpm whereas
during thermo-hydrodynamic analysis, this rise in
temperature has been changed from 19 K to 45 K
only. Therefore, there was steep rise in temperature
during iso-thermal analysis as compared to thermal
analysis.
The variation of wall shear stress at 5500 rpm of
journal speed has been represented in Fig. 6. It has
been found the maximum value of wall shear stress
was 6.354e+4 and 2.94e+4 for iso-thermal and
thermo-hydrodynamic analysis respectively.
The variation of oil film forces on the journal
speed has been presented in Fig. 7. It has been
observed that the 20 N oil film force at 2500 rpm and
it rises to 45 N when the journal speed varies from
2500 to 5500 rpm in case of iso-thermal analysis. The
A. Iso-Thermal Analysis B. Thermo-hydrodynamic Analysis
Fig. 4. Comparison of Temperature Distribution Profile for Isothermal and thermo-hydrodynamic analysis at journal
speed = 5500 rpm
Fig. 5. Variation of oil film temperature with the increase in journal speed from 2500 rpm to 5500 rpm for
iso-thermal and thermo-hydrodynamic analysis
6. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
51
A. Iso-thermal Analysis B. Thermo-hydrodynamic Analysis
Fig. 6. Comparison of Wall Shear Stress for Isothermal and thermo-hydrodynamic analysis at journal speed = 5500 rpm
Fig. 7. Variation of oil film forces with the increase in journal speed from 2500 rpm to 5500 rpm for
iso-thermal and thermo-hydrodynamic analysis
rise of oil film force for thermo-hydrodynamic
analysis has been found from 19 N to 36 N when the
journal speed varies from 2500 rpm to 5500 rpm.
5. CONCLUSIONS
Thermo-hydrodynamic analysis for circular journal
bearing has been carried out using the application of
Computational Fluid Dynamics. The bearing
performance parameters such as pressure,
temperature, oil film forces and wall shear stress has
been evaluated at a journal speed varying from 2500
rpm to 5500 rpm taking eccentricity ratio = 0.8, radial
clearance = 200 micron and L/D ratio of 1. It has been
found that when viscosity is kept constant the
temperature rise is more in the lubricant and the
maximum pressure obtained is also high. But it does
not represent real life time scenario as when
temperature increases, viscosity of lubricant decreases
which affects the load carrying capacity of bearing.
Therefore obtaining the bearing performance
characteristics by keeping constant viscosity may
gives wrong prediction about the bearing. So the
present analysis may be helpful in prediction of
bearing performance parameters in actual working
conditions and may help in increased life of the
bearing.
7. International Journal of Research in Advent Technology, Vol.2, No.7, July 2014
E-ISSN: 2321-9637
52
REFERENCES
[1] Hughes, W. F. ; Osterle, F. (1958): Temperature
Effects in Journal Bearing Lubrication. ASLE
Transactions, 1(1), pp. 210-212.
[2] Gertzos, K. P.; Nikolakopoulos, P. G.;
Papadopoulos, C. A. (2008): CFD analysis of
journal bearing hydrodynamic lubrication by
Bingham lubricant. Tribology International,
41(12), pp. 1190-1204.
[3] Chauhan, A.; Sehgal, R.; Sharma, R. K. (2011):
Investigations on the thermal effects in non-circular
journal bearings. Tribology International,
44(12), pp. 1765-1773.
[4] Ouadoud, A.; Mouchtachi, A.; Boutammachte, N.
(2011): Numerical simulation CFD, FSI of a
hydrodynamic journal bearing. Journal of
Advanced Research in Mechanical Engineering,
2(1), pp. 33-38.
[5] Cupillard, S.; Glavatskih, S.; Cervantes, M. J.
(2008): Computational fluid dynamics analysis of
a journal bearing with surface texturing. Proc.
IMechE, Engineering Tribology, 222(2), pp. 97-
107.
[6] Sahu, M.; Giri, A. K.; Das, A. (2012):
Thermohydrodynamic Analysis of a Journal
Bearing Using CFD as a Tool. International
Journal of Scientific and Research Publications,
2(9), pp 1-5.
[7] Basri, S.; Gethin, D. T. (1990): A Comparative
Study of the Thermal Behaviour of Profile Bore
Bearings. Tribology International, 23, pp. 265-
276.
[8] Hussain A.; Mistry, K.; Biswas, S. (1996):
Thermal Analysis of Noncircular Bearings.
ASME, 118, pp. 246-254.
[9] Liu, H.; Xu, H. ; Ellison, P. J. (2010):
Application of Computational Fluid Dynamics
and Fluid–Structure Interaction Method to the
Lubrication Study of a Rotor–Bearing System.
Tribology Letters, 38, pp. 325–336.
[10] Li, Q.; Liu, S.; Pan, X.; Zheng, S. (2012): A new
method for studying the 3D transient flow of
misaligned journal bearings in flexible rotor-bearing
systems. Journal of Zhejiang University-
SCIENCE, 13(4), pp. 293-310.
[11] Panday, K. M.; Choudhary, P. L.; Kumar, N. P.
(2012): Numerical Unstaedy Analysis of Thin
Film Lubricated Journal Bearing. International
Journal of Engineering and Technology, 4(2), pp
185-191.