Thermal Effects in Slider Bearings With Limited Corrugation and Power-Law Lubricant

2012 ◽  
Author(s):  
B. P. Huynh
Keyword(s):  
Power Law ◽  
Thermal Effects ◽  
Shear Thickening ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Slider Bearings ◽  
Influence Of Temperature On ◽  
Computational Fluid Dynamics Cfd ◽  
Dependent Viscosity ◽  
Power Law Index

Influence of temperature on the performance of slider bearings of infinite width but having corrugation of limited extent is investigated numerically, using a commercial Computational Fluid Dynamics (CFD) software package. Lubricant is assumed to be a fluid of power-law type with temperature-dependent viscosity. Over a range of the power-law index, combined effects of temperature and the corrugated section’s location on load-supporting capacity Fy of the bearing’s fluid film are considered. Influence of the bearing-gap surfaces’ thermal boundary condition is also examined. Compared with isothermal situation, thermal effects result in significant reduction in Fy, especially with shear-thickening lubricants. This reduction in Fy is also affected significantly by the corrugated section’s location.

Effects of Temperature-Dependent Viscosity Variations and Boundary Conditions on Fully Developed Laminar Forced Convection in a Semicircular Duct

1998 ◽  
Vol 120 (3) ◽  
pp. 600-605 ◽  
Author(s):  
T. M. Harms ◽  
M. A. Jog ◽  
R. M. Manglik
Keyword(s):  
Boundary Conditions ◽  
Power Law ◽  
Numerical Solutions ◽  
Strong Dependence ◽  
Laminar Flows ◽  
Temperature Fields ◽  
Traditional Values ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity

Fully developed laminar flows in a semicircular duct with temperature-dependent viscosity variations in the flow cross section are analyzed, where the viscosity-temperature behavior is described by the Arrhenius model. Both the T and H1 boundary conditions are considered, as they represent the most fundamental heating/cooling conditions encountered in practical compact heat exchanger applications. Numerical solutions for the flow velocity and the temperature fields have been obtained by finite difference technique. The friction factor and Nusselt number results display a strong dependence on the viscosity ratio (μw/μb), and this is correlated using the classical power-law relationship. However, results indicate that the power-law exponents are significantly different from traditional values for circular tube. They are found to be functions of the flow geometry, boundary condition, and direction of heat transfer (heating or cooling).

Numerical Investigation of Slider Bearings With Limited Corrugation and Power-Law Lubricant

2011 ◽  
Author(s):  
B. P. Huynh
Keyword(s):  
Power Law ◽  
Software Package ◽  
Smooth Surface ◽  
Wave Amplitude ◽  
Limited Extent ◽  
Supporting Capacity ◽  
Slider Bearings ◽  
Computational Fluid Dynamics Cfd ◽  
The Difference ◽  
Power Law Index

Performance of slider bearings of infinite width but having corrugation of limited extent is investigated numerically, using a commercial Computational Fluid Dynamics (CFD) software package. Lubricant is assumed to be a fluid of power-law type. Over a range of the power-law index, effects of the corrugated section’s location on pressure distribution in the bearing’s fluid film and its load supporting capacity is considered. Load-supporting capacity increases with power-law index n, but saturates when n reaches about 1.7. Ratio of load-supporting capacities between corrugated bearing and smooth-surface bearing varies significantly with respect to n when n < [about 0.8], but stays nearly constant at higher n value. Larger corrugation-wave amplitude enhances the difference in load-supporting capacity between corrugated bearings and the smooth-surface one.

scholarly journals Rayleigh-Bénard Convection of Non-Newtonian Power-Law Fluids with Temperature-Dependent Viscosity

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Mourad Kaddiri ◽  
Mohamed Naïmi ◽  
Abdelghani Raji ◽  
Mohammed Hasnaoui
Keyword(s):  
Heat Transfer ◽  
Power Law ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Bénard Convection ◽  
Benard Convection ◽  
Power Law Fluids ◽  
Dependent Viscosity ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

Two-dimensional steady-state Rayleigh-Bénard convection of thermodependent power-law fluids confined in a square cavity, heated from the bottom and cooled on the top with uniform heat fluxes, has been conducted numerically using a finite difference technique. The effects of the governing parameters, which are the Pearson number (0≤m≤10), the flow behaviour index (0.6≤n≤1.4), and the Rayleigh number (0<Ra≤105), on the flow onset, flow structure, and heat transfer have been examined. The heatlines concept has been used to explain the heat transfer deterioration due to temperature-dependent viscosity effect that m expresses.

Thermal Effects in Rolling/Sliding Contacts: Part 2—Analysis of Thermal Effects in Fluid Film

1987 ◽  
Vol 109 (3) ◽  
pp. 512-517 ◽  
Author(s):  
Farshid Sadeghi ◽  
Thomas A. Dow
Keyword(s):  
Thermal Effects ◽  
Elastohydrodynamic Lubrication ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
Sliding Contacts ◽  
Temperature Dependent Viscosity ◽  
Pure Rolling ◽  
Dependent Viscosity ◽  
Energy Equations ◽  
Experimental Pressure

A two dimensional numerical solution to the problem of thermal elastohydrodynamic lubrication of rolling/sliding contacts was obtained using a finite difference formulation. The technique involves the simultaneous solution of the thermal Reynolds’ equation, the elasticity equation, and the two dimensional energy equation. A pressure and temperature dependent viscosity for a synthetic paraffinic hydrocarbon lubricant (XRM-109F) was considered in the solution of the Reynolds’ and energy equations. The experimental pressure and surface temperature measurements obtained by Dow and Kannel [1] were used in evaluating the results of the numerical analysis for the cases of pure rolling and slip conditions.

scholarly journals Numerical investigation of magnetohydrodynamic slip flow of power-law nanofluid with temperature dependent viscosity and thermal conductivity over a permeable surface

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 867-876 ◽  
Author(s):  
Sajid Hussain ◽  
Asim Aziz ◽  
Chaudhry Masood Khalique ◽  
Taha Aziz
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Thermal Conductivity ◽  
Boundary Layer ◽  
Numerical Investigation ◽  
Power Law ◽  
Slip Flow ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity

AbstractIn this paper, a numerical investigation is carried out to study the effect of temperature dependent viscosity and thermal conductivity on heat transfer and slip flow of electrically conducting non-Newtonian nanofluids. The power-law model is considered for water based nanofluids and a magnetic field is applied in the transverse direction to the flow. The governing partial differential equations(PDEs) along with the slip boundary conditions are transformed into ordinary differential equations(ODEs) using a similarity technique. The resulting ODEs are numerically solved by using fourth order Runge-Kutta and shooting methods. Numerical computations for the velocity and temperature profiles, the skin friction coefficient and the Nusselt number are presented in the form of graphs and tables. The velocity gradient at the boundary is highest for pseudoplastic fluids followed by Newtonian and then dilatant fluids. Increasing the viscosity of the nanofluid and the volume of nanoparticles reduces the rate of heat transfer and enhances the thickness of the momentum boundary layer. The increase in strength of the applied transverse magnetic field and suction velocity increases fluid motion and decreases the temperature distribution within the boundary layer. Increase in the slip velocity enhances the rate of heat transfer whereas thermal slip reduces the rate of heat transfer.

A Thermo-Elasto-Hydrodynamic Study of Journal Bearing With Controlled Deflection

1993 ◽  
Vol 115 (3) ◽  
pp. 550-556 ◽  
Author(s):  
N. O. Freund ◽  
A. K. Tieu
Keyword(s):  
Thermal Effects ◽  
Journal Bearing ◽  
Load Capacity ◽  
Three Dimensions ◽  
The Finite Element Method ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Lubricating Film ◽  
Hydrodynamic Study ◽  
Dependent Viscosity

A thermo-elasto-hydrodynamic study of a specially modified journal bearing is included. A numerical simulation is carried out by the finite element method, coupling the deflection of the bearing housing and the pressure derived from the Reynolds equation. In turn, this is coupled through its temperature dependent viscosity terms to the energy equation. Elastic effects are treated in three dimensions. Thermal effects are considered in three dimensions in both the lubricating film and bearing housing with convection specified on the housing boundaries. The bearing is specially modified with an undercut on the bearing housing. It will be demonstrated that by design an appropriate deflection of the undercut can be achieved to improve the load capacity.

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