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.

Crosswise stream of methanol–iron oxide (CH3OH–Fe3O4) with temperature-dependent viscosity and suction/injection effects

2019 ◽  
Vol 233 (5) ◽  
pp. 1013-1023 ◽  
Author(s):  
Rabil Tabassum ◽  
R Mehmood
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Treatment Plant ◽  
Exponential Model ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Coating Materials ◽  
Similarity Transformations ◽  
Dependent Viscosity ◽  
Energy Equations

Manufacturing of modern coating materials doped with magnetic nanoparticles has arisen as an exciting new area of materials processing fluid dynamics. Methanol is primarily used in chemical manufacturing, specialized vehicles fuel, energy carrier, as an antifreeze in pipelines, in wastewater treatment plant, and many more. In this article, a mathematical model is therefore developed to study crosswise flow of methanol-based ferromagnetic fluid through a permeable medium with suction/injection effects. Temperature-dependent viscosity is taken with Reynolds exponential model. The Tiwari–Das and Maxwell–Garnett nanofluid models are used, which alters the electrical conductivity, density, and thermal conductivity properties with nanoparticle volume fraction. The two-dimensional mass, momentum, and energy equations are normalized into nonlinear system comprising ordinary differential equations via appropriate similarity transformations. The solution of the emerging physical problem is attained by shooting scheme in MATLAB symbolic software. Validation of the results is presented through comparison with previously reported literature in the limiting sense. The influence of pertinent parameters on the flow and heat transfer characteristics is revealed through graphs. It is found that velocity profiles are suppressed with greater magnetic parameter and porosity parameters but temperature profile is enhanced. Velocity and temperature profiles for injection case are higher when compared with the suction phenomenon. Shear stress at the wall is decreased with volume fraction. Heat transfer gradient at the wall is significantly enhanced with volume fraction.

scholarly journals Investigation of Entropy in Two-Dimensional Peristaltic Flow with Temperature Dependent Viscosity, Thermal and Electrical Conductivity

Entropy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 200
Author(s):  
Muhammad Qasim ◽  
Zafar Ali ◽  
Umer Farooq ◽  
Dianchen Lu
Keyword(s):  
Heat Transfer ◽  
Electrical Conductivity ◽  
Entropy Production ◽  
Linear Equations ◽  
Physical Parameters ◽  
Two Dimensional ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity ◽  
The Impact

This study comprehensively explores the generalized form of two-dimensional peristaltic motions of incompressible fluid through temperature-dependent physical properties in a non-symmetric channel. Generation of entropy in the system, carrying Joule heat and Lorentz force is also examined. Viscous dissipation is not ignored, for viewing in-depth, effects of heat transmission and entropy production. The modeling of equations is tracked first in fixed and then in wave frame. The resultant set of coupled non-linear equations are solved numerically by utilizing NDSolve in Mathematica. Comparison between NDSolve and the numerical results obtained through bvp4c MATLAB is made for the validation of our numerical codes. The attained results are found to be in excellent agreement. The impact of control parameters on the velocity profiles, pressure gradient, heat transfer, streamlines and entropy production are studied and discussed graphically. It is witnessed that entropy production and heat transfer are increased significantly subject to the enhancement of Hartman number, Brinkman number and electrical conductivity parameter. Hence, choosing appropriate values of physical parameters, performance and efficiency of flow structure and system can be improved. The results reported provide a virtuous insight into bio energy systems providing a useful standard for experimental and extra progressive computational multiphysics simulations.

Laminar Flow Heat Transfer and Fluid Flow for Liquids With Temperature-Dependent Viscosity

1968 ◽  
Vol 90 (4) ◽  
pp. 385-392 ◽  
Author(s):  
F. L. Test
Keyword(s):  
Heat Transfer ◽  
Analytical Approach ◽  
Experimental Approach ◽  
Hot Wire ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Flow Heat ◽  
Dependent Viscosity ◽  
Energy Equations

An analytical and experimental study is made of liquids with a temperature dependent viscosity. The analytical approach is a numerical solution of the momentum, continuity, and energy equations. The significance of various terms in the equations is considered. The experimental approach involves the use of hot wire techniques for the determination of velocity profiles. Correlations are obtained for the Nusselt number and friction factor.

Effects of Temperature Dependent Properties on the Laminar Forced Convection in Straight Microchannels With Uniform Wall Temperature

2013 ◽  
Author(s):  
Stefano Del Giudice ◽  
Stefano Savino ◽  
Carlo Nonino
Keyword(s):  
Thermal Conductivity ◽  
Nusselt Number ◽  
Forced Convection ◽  
Superposition Method ◽  
Brinkman Number ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Effects Of Temperature ◽  
Dependent Viscosity ◽  
Energy Equations

The paper reports the results of a parametric investigation on the effects of temperature dependent viscosity and thermal conductivity on forced convection in simultaneously developing laminar flows of liquids in straight microchannels of constant cross-sections. Uniform temperature boundary conditions are specified at the microchannel walls. Viscosity is assumed to vary with temperature according to an exponential relation, while a linear dependence of thermal conductivity on temperature is assumed. The other fluid properties are held constant. Two different cross-sectional geometries, namely circular and flat microchannels, are considered. A finite element procedure is employed for the solution of the parabolized momentum and energy equations. The parabolic approximation of the Navier-Stokes and energy equations can be considered adequate for values of the Reynolds and Péclet numbers larger than 50. Computed axial distributions of the local Nusselt number are presented for different values of the Brinkman number and of the viscosity and thermal conductivity Pearson numbers. Moreover, a superposition method is proved to be applicable in order to obtain an approximate value of the Nusselt number by separately considering the effects of temperature dependent viscosity and those of temperature dependent thermal conductivity. Finally, it is found that the influence of the temperature dependence of thermal conductivity on the value of the Nusselt number is almost independent of the value of the Brinkman number, i.e., it is approximately the same no matter whether viscous dissipation is negligible or not.

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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