The Effects of Fluid Inertia Forces in Parallel Circular Squeeze Film Bearings Lubricated With Pseudo-Plastic Fluids

1986 ◽  
Vol 108 (2) ◽  
pp. 282-287 ◽  
Author(s):  
Hiromu Hashimoto ◽  
Sanae Wada
Keyword(s):  
Numerical Solutions ◽  
Momentum Equation ◽  
Mean Value ◽  
Squeeze Film ◽  
Graphical Form ◽  
Shear Strain Rate ◽  
Fluid Inertia ◽  
Film Pressure ◽  
Inertia Forces ◽  
Plastic Fluids

The effects of fluid inertia forces in parallel circular squeeze film bearings lubricated with pseudo-plastic fluids are examined theoretically. In the derivation of lubrication equation, the cubic equation obtained from the empirical flow curves for pseudo-plastic fluids is used as the relation between shear stress and shear strain rate, and the inertia term in the momentum equation is approximated by the mean value averaged across the film thickness. Numerical solutions for the film pressure of circular bearings lubricated with Newtonian and pseudo-plastic fluids under the sinusoidal squeeze motion are presented in graphical form and the effects of inertia forces on the film pressure are determined.

Effects of couple stresses and convective inertia forces in parallel circular squeeze‐film plates

2004 ◽  
Vol 56 (6) ◽  
pp. 318-323 ◽  
Author(s):  
Jaw‐Ren Lin ◽  
Rong‐Fang Lu ◽  
Won‐Hsion Liao ◽  
Chia‐Chuan Kuo
Keyword(s):  
Couple Stress ◽  
Numerical Solutions ◽  
Continuum Theory ◽  
Momentum Equation ◽  
Mean Value ◽  
Squeeze Film ◽  
Combined Effects ◽  
Fluid Inertia ◽  
Couple Stresses ◽  
Inertia Forces

A theoretical study of the combined effects of non‐Newtonian couple stresses and fluid inertia forces on the squeeze‐film behaviors for parallel circular plates is presented in this paper. Based upon the micro‐continuum theory, the Stokes constitutive equations are used to account for the couple stress effects resulting from the lubricant blended with various additives. The convective inertia forces included in the momentum equation are approximated by the mean value averaged across the fluid film thickness. Numerical solutions for the squeezing film characteristics are presented for various values of couple stress parameter and Reynolds number. Comparing with the classical Newtonian non‐inertia flow, the combined effects of couple stresses and convective inertia forces result in a larger load‐carrying capacity and therefore, increase the response time of the squeezing film plates.

Viscoelastic Squeeze Film Characteristics With Inertia Effects Between Two Parallel Circular Plates Under Sinusoidal Motion

1994 ◽  
Vol 116 (1) ◽  
pp. 161-166 ◽  
Author(s):  
H. Hashimoto
Keyword(s):  
Maxwell Model ◽  
Momentum Equation ◽  
Mean Value ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Lubrication Equation ◽  
Model Combining ◽  
Sinusoidal Motion ◽  
Film Characteristics

In this paper, viscoelastic squeeze film characteristics subjected to fluid inertia effects are investigated theoretically in the case of parallel circular type squeeze films. In the development of modified lubrication equations, the nonlinear Maxwell model combining the Rabinowitsch model and Maxwell model is used as a constitutive equation for the viscoelastic fluids, and the inertia term in the momentum equation is approximated by the mean value averaged over the film thickness. Applying the modified lubrication equation to parallel circular type squeeze films under sinusoidal motion, the variation of the pressure distribution with time is calculated numerically for various types of fluids such as Newtonian, pseudo-plastic, linear Maxwell and nonlinear Maxwell fluids. Some numerical results are presented in graphic form, and the effects of inertia forces on the viscoelastic squeeze film characteristics are discussed.

Modelling Fluid Inertia Forces of Short Journal Bearings for Rotordynamic Applications

1993 ◽  
Author(s):  
A. El-Shafei
Keyword(s):  
Momentum Equation ◽  
Journal Bearings ◽  
Fluid Inertia ◽  
Radial Acceleration ◽  
Damping Characteristics ◽  
Energy Approximation ◽  
Form Model ◽  
Fluid Inertia Effect ◽  
Stiffness And Damping ◽  
Inertia Forces

Abstract It has been recently suggested that fluid inertia may play an important role in the dynamic behavior of rotors supported on journal bearings. This paper presents a model for fluid inertia forces in short cylindrical journal bearings based on an energy approximation. The inertialess velocity profiles predicted by the solution of Reynolds’ equation are inserted in the axial momentum equation multiplied by the axial velocity profile and integrated across the film thickness, to obtain the pressure in short journal bearings including the fluid inertia effect. The pressure is then integrated to obtain the fluid inertia forces. It is shown that the inertia forces thus obtained are proportional to the usual radial, centripetal, tangential and coriolis accelerations of the journal, in addition to a nonlinear radial acceleration. Moreover, it is shown that the inertia forces contribute to the stiffness and damping characteristics of the journal bearings. The inertia coefficients of the bearings are obtained in cartezian and cylindrical coordinates, for both uncavitated and cavitated bearings, and are plotted versus the eccentricity ratio. The model thus obtained is an analytical closed form model for fluid inertia forces in short journal bearings. Such a model is the most suitable for rotordynamic applications, particularly for time transient rotordynamic simulations.

Fluid Inertia Effects in a Non-Newtonian Squeeze Film Between Two Plane Annuli

1999 ◽  
Vol 122 (4) ◽  
pp. 872-875 ◽  
Author(s):  
R. Usha and ◽  
P. Vimala
Keyword(s):  
Carrying Capacity ◽  
Integral Method ◽  
Squeeze Flow ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Load Carrying ◽  
Analytical Expressions ◽  
Plastic Fluids

An analysis is presented for the laminar squeeze flow of an incompressible powerlaw fluid between parallel plane annuli using the modified lubrication theory and energy integral method. The local and the convective inertia of the flow are considered in the investigation. Analytical expressions for the load carrying capacity of the squeeze film are obtained using both the methods and are compared with those based on the assumption of inertialess flow. It is observed that the inertia correction in the load carrying capacity is more significant for pseudo-plastic fluids, n<1.[S0742-4787(00)00504-X]

Effects of fluid inertia forces on the squeeze film characteristics of conical plates-ferromagnetic fluid model

2012 ◽  
Vol 25 (7) ◽  
pp. 429-439 ◽  
Author(s):  
Jaw-Ren Lin ◽  
Ming-Chung Lin ◽  
Tzu-Chen Hung ◽  
Pin-Yu Wang
Keyword(s):  
Fluid Model ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Ferromagnetic Fluid ◽  
Film Characteristics ◽  
Inertia Forces

Theoretical Investigation of Couple Stress Squeeze Films in a Curved Circular Geometry

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Vimala Manivasakan ◽  
Govindarajan Sumathi
Keyword(s):  
Theoretical Investigation ◽  
Carrying Capacity ◽  
Couple Stress ◽  
Squeeze Flow ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Fluid Inertia ◽  
Load Carrying ◽  
Inertia Forces ◽  
Good Agreement

A theoretical investigation of the laminar squeeze flow of a couple-stress fluid between a flat circular static disk and an axisymmetric curved circular moving disk has been carried out using modified lubrication theory and microcontinuum theory. The combined effects of fluid inertia forces, curvature of the disk and non-Newtonian couple stresses on the squeeze film behavior are investigated analytically. Each of these effects and their combinations show a significant enhancement in the squeeze film behavior, and these are studied through their effects on the squeeze film pressure and the load carrying capacity of the fluid film as a function of time. Two different forms of the gapwidth between the disks have been considered, and the results have been shown to be in good agreement with the existing literature.

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