Couple-stress squeeze films between porous rectangular plates

2003 ◽  
Vol 217 (3) ◽  
pp. 229-234 ◽  
Author(s):  
N. B. Naduvinamani ◽  
Syeda Tasneem Fathima ◽  
P. S. Hiremath
Keyword(s):  
Couple Stress ◽  
Reynolds Equation ◽  
Velocity Slip ◽  
Squeeze Film ◽  
Rectangular Plates ◽  
Couple Stresses ◽  
Load Carrying ◽  
Porous Interface ◽  
Couple Stress Fluids ◽  
Film Lubrication

In this paper, the squeeze-film lubrication theory between two isotropic porous rectangular plates has been advanced to analyse the effects of couple stresses arising due to the presence of microstructure additives in the lubricant, using the Stokes theory of couple-stress fluids. The most general form of the modified Reynolds equation is derived for the squeeze-film lubrication of the porous rectangular plates by taking into account of the velocity slip at the porous interface. An eigentype of expression is obtained for the squeeze-film pressure. The effects of the isotropic permeability, the couple stresses and the velocity slip parameters on the characteristics of the squeeze-film lubrication are discussed. A significant increase in the load-carrying capacity and the delayed squeeze-film time are observed for the couple-stress fluids in comparison with Newtonian fluids.

Derivation of non-Newtonian squeeze-film Reynolds equation between convex surfaces and application to two different cylinders

2007 ◽  
Vol 221 (7) ◽  
pp. 813-821 ◽  
Author(s):  
J-R Lin
Keyword(s):  
Couple Stress ◽  
Reynolds Equation ◽  
Continuum Theory ◽  
Type Equation ◽  
Squeeze Film ◽  
Convex Surfaces ◽  
Couple Stresses ◽  
Load Carrying ◽  
Film Characteristics ◽  
Couple Stress Fluids

The derivation of non-Newtonian squeeze-film Reynolds-type equation between two convex surfaces and its application are of interest in the present study. Based upon the Stokes micro-continuum theory, the non-Newtonian squeeze-film Reynolds-type equation between two convex surfaces is derived to take into account the effects of couple stresses resulting from the lubricant blended with various additives. This non-Newtonian squeeze-film Reynolds-type equation is applicable to squeeze-film bearings lubricated with couple stress fluids when the general upper film shape and the lower film shape are specified. To guide the use of the equation, the squeeze-film mechanism between two different cylinders of infinite width with non-Newtonian couple stress fluids is illustrated. Comparing with the Newtonian-lubricant case, the presence of non-Newtonian couple stresses provides an increase in the load-carrying capacity, and therefore lengthens the approaching time. In addition, the effects of couple stresses on the squeeze film characteristics are more pronounced at lower squeeze-film height with larger couple stress parameters and larger radius ratios of cylinders. As the value of radius ratio approaches infinity, the present results agree closely with those of the previous studies by Hamrock [6] and by Lin et al. [19], respectively; it provides a support to the present study.

scholarly journals MULTIGRID METHOD FOR THE SOLUTION OF COMBINED EFFECT OF VISCOSITY VARIATION AND SURFACE ROUGHNESS ON THE SQUEEZE FILM LUBRICATION OF JOURNAL BEARINGS

2017 ◽  
Vol 46 (1) ◽  
pp. 1-8
Author(s):  
Vishwanath B. Awati ◽  
Ashwini Kengangutti ◽  
Mahesh Kumar N.
Keyword(s):  
Surface Roughness ◽  
Carrying Capacity ◽  
Micropolar Fluid ◽  
Reynolds Equation ◽  
Multigrid Method ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Viscosity Variation ◽  
Film Lubrication

The paper presents, the multigrid method for the solution of combined effect of surface roughness and viscosity variation on the squeeze film lubrication of a short journal bearing operating with micropolar fluid. The modified Reynolds equation which incorporates the variation of viscosity in micropolar fluid is analysed using Multigrid method. The governing modified Reynolds equation is solved numerically for the fluid film pressure and bearing characteristics viz. load carrying capacity and squeeze time. The analysis of the results predicts that, the viscosity variation factor decreases the load carrying capacity and squeeze film time, resulting into a longer bearing life. The results are compared with the corresponding analytical solutions.

scholarly journals Effect of Surface Roughness and Viscosity-Pressure Dependency on the Couple Stress Squeeze Film Characteristics of Parallel Circular Plates

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Neminath Bhujappa Naduvinamani ◽  
Siddangouda Apparao ◽  
Ayyappa G. Hiremath
Keyword(s):  
Surface Roughness ◽  
Carrying Capacity ◽  
Couple Stress ◽  
Reynolds Equation ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Circular Plates ◽  
Pressure Dependency ◽  
Load Carrying ◽  
Film Characteristics

Combined effects of surface roughness and viscosity-pressure dependency on the couple stress squeeze film characteristics of parallel circular plates are presented. On the basis of Christensen’s stochastic theory, two types of one-dimensional roughness structures, namely, the radial roughness and azimuthal roughness patterns, are considered and the stochastic modified Reynolds equation for these two types of roughness patterns is derived for Stokes couple stress fluid by taking into account variation of viscosity with pressure. The standard perturbation technique is employed to solve the averaged Reynolds equation and closed form expressions for the mean fluid film pressure, load carrying capacity, and squeeze film time are obtained. It is found that the effects of couple stresses and viscosity-pressure dependency are to increase the load carrying capacity, and squeeze film time for both types of roughness patterns. The effect of azimuthal (radial) roughness pattern is to increase (decrease) these squeeze film characteristics as compared to the corresponding smooth case.

An Analysis of the Squeeze Film Between Porous Rectangular Plates

1972 ◽  
Vol 94 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Hai Wu
Keyword(s):  
Film Thickness ◽  
Pressure Distribution ◽  
Laplace Equation ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Rectangular Plates ◽  
Load Carrying ◽  
In Series

The squeeze film between two rectangular plates when one has a porous facing is studied theoretically. The problem is described by the modified Reynolds equation in the film region and the Laplace equation in the porous region. Results are presented for pressure distribution, load-carrying capacity, and film thickness as functions of time in series form. The effect of the porous facing on the squeeze film behavior is discussed and found to be important.

Squeeze Film Lubrication on a Rigid Sphere and a Flat Porous Plate with Piezo-Viscosity and Couple Stress Fluid

2020 ◽  
Vol 401 ◽  
pp. 140-147
Author(s):  
B.N. Hanumagowda ◽  
C.K. Sreekala ◽  
Noorjahan ◽  
Oluwole Daniel Makinde
Keyword(s):  
Analytical Solution ◽  
Couple Stress ◽  
Reynolds Equation ◽  
Approximate Analytical Solution ◽  
Porous Plate ◽  
Squeeze Film ◽  
Rigid Sphere ◽  
Remarkable Similarity ◽  
Darcy’S Equations ◽  
Film Lubrication

The paper aims to conduct a theoretical analysis about squeeze film behaviour with piezo-viscosity on a fluid lubricated with polar additives on a rigid sphere and a flat porous plate. By taking into account of microcontinum theory of stokes, Barus formula and Darcy’s equations, Reynolds equation in modified form is derived by bearing in mind the variation of viscosity along film thickness. An approximate analytical solution for fluid film pressure, dimensionless load and squeezing time is derived. The results are presented numerically and graphically. To make obvious the accuracy, the results are compared with accessible literature and a remarkable similarity is been reported

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