scholarly journals Squeeze Film Lubrication between Rough Poroelastic Rectangular Plates with Micropolar Fluid: A Special Reference to the Study of Synovial Joint Lubrication

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
N. B. Naduvinamani ◽  
G. K. Savitramma
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Micropolar Fluid ◽  
Stochastic Theory ◽  
Squeeze Film ◽  
Rectangular Plates ◽  
Synovial Joint ◽  
Synovial Joints ◽  
Joint Lubrication ◽  
Load Carrying

The effects of surface roughness and poroelasticity on the micropolar squeeze film behavior between rectangular plates in general and that of synovial joints in particular are presented in this paper. The modified Reynolds equation, which incorporates the randomized surface roughness structure as well as elastic nature of articular cartilage with micropolar fluid as lubricant, is derived. The load-carrying capacity and time of approach as functions of film thickness during normal articulation of joints are obtained by using Christensen stochastic theory for rough surfaces with the assumption that the roughness asperity heights are to be small compared to the film thickness. It is observed that the effect of surface roughness has considerable effects on lubrication mechanism of synovial joints.

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.

Effects of Surface Roughness and Non-Newtonian Micropolar Fluid Squeeze Film between Conical Bearings

2017 ◽  
Vol 72 (12) ◽  
pp. 1151-1158 ◽  
Author(s):  
P. S. Rao ◽  
Birendra Murmu ◽  
Santosh Agarwal
Keyword(s):  
Surface Roughness ◽  
Response Time ◽  
Micropolar Fluid ◽  
Load Capacity ◽  
Squeeze Film ◽  
Graphical Form ◽  
Load Carrying ◽  
Transverse Roughness ◽  
Improved Performance ◽  
Bearing System

AbstractBased on the micropolar fluid models of Eringen and Christensen’s stochastic theories, the analysis of the effects of surface roughness and the squeeze film lubrication problems between conical bearings are presented. The concerned nondimensional Reynolds equation is solved with appropriate boundary conditions in dimensionless form to find the pressure distribution, which is then used to obtain the expression for load-carrying capacity, paving the way for the calculation of response time. Computed values of pressure, load capacity, and response time are displayed in graphical form. This investigation reveals that the bearing system admits an improved performance as compared with that of a bearing system working with a conventional lubricant. According to the results, the effects of transverse roughness provide an increase in the bearing characteristics as compared with the smooth bearing lubricated with micropolar fluid whereas the influences of longitudinal roughness yield a reversed trend. The quantifiable effects of rough surfaces and non-Newtonian fluids on bearing performances are more pronounced for the roughness and micropolar parameters.

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.

Effect of Rolling Velocity and Maximum Hertzian Pressure on Fluid Film in Steady State EHL Line Contact with Rough Surface and Linear Piezoviscosity

2014 ◽  
Vol 592-594 ◽  
pp. 1371-1375
Author(s):  
Nitesh Talekar ◽  
Punit Kumar
Keyword(s):  
Surface Roughness ◽  
Steady State ◽  
Film Thickness ◽  
Rough Surface ◽  
Computer Code ◽  
Fluid Film ◽  
Line Contact ◽  
Rolling Velocity ◽  
Load Carrying ◽  
Lubricated Contact

Consideration of surface roughness in steady state EHL line contact is the first step towards understanding the lubrication of rough surface problem. Current paper investigates the use of sinusoidal waviness in the contact; more precisely it gives performance of real fluid in EHL line contact. The effect of various parameters like rolling velocity (U) and maximum Hertzian pressure (ph) on surface roughness by using properties of linear and exponential piezo-viscosity is taken into consideration to evaluate behavior of pressure distribution of load carrying fluid film and film thickness. Full isothermal, Newtonian simulation of EHL problem gives described effects. Spiking or fluctuation of pressure and film thickness curves is expected to show presence of irregularities on the surface chosen and amount of fluctuation depends on certain parameters and intensity of irregularities present. Rolling side domain of-4.5 ≤ X ≤ 1.5 with grid size ∆X=0.01375 is selected. A computer code is developed to solve Reynolds equation, which governs the generation of pressure in the lubricated contact zone is discritized and solved along with load balance equation using Newton-Raphson technique.

Pressure generation in rough conical bearing using non-Newtonian Rabinowitsch fluid with variable viscosity

2019 ◽  
Vol 71 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Pentyala Srinivasa Rao ◽  
Amit Kumar Rahul
Keyword(s):  
Surface Roughness ◽  
Response Time ◽  
Fluid Model ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Content Type ◽  
Pressure Load ◽  
Load Carrying ◽  
Conical Bearing ◽  
Viscosity Variation

Purpose This paper aims to investigate the effect of surface roughness (radial and azimuthal) and viscosity variation on a squeeze film of a conical bearing with a non-Newtonian lubricant by using Rabinowitsch fluid model. Design/methodology/approach The main objective is to determine the stochastic nonlinear modified Reynolds equation for rough conical bearing. Later, first-order closed-form solutions are obtained using a small perturbation method and are numerically solved using the Gauss quadrature method. Findings The findings of this paper, numerical calculations, are analyzed for pressure, load carrying capacity and response time. The simulated results indicate that the influence of surface roughness increases the pressure, load carrying capacity and response time, whereas the viscosity variation factor decreases the pressure, load and response time. Originality/value According to both types of surface roughness with viscosity variation, the performance of a squeeze film rough conical bearing was improved by using Rabinowitsch fluid model. As it is inevitable to consider viscosity variation for bearing designer, it leads to a long life period of conical bearing.

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.

scholarly journals Hydrodynamic lubrication of rough surfaces

1982 ◽  
Vol 383 (1785) ◽  
pp. 439-446 ◽  
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Reynolds Equation ◽  
Hydrodynamic Lubrication ◽  
Rough Surfaces ◽  
Homogenization Method ◽  
Squeeze Film ◽  
Spatial Average

Using the two-space homogenization method we derive an averaged Reynolds equation that is correct to O (< H 6 > — < H 3 > 2 ), where H is the total film thickness and the angle brackets denote a spatial average. Applications of this mean Reynolds equation to a squeeze-film bearing with a sinusoidal or an isotropic surface roughness are discussed.

Sign in / Sign up

Export Citation Format

Share Document