Study of Conical Whirl Instability of Self-Acting Porous Gas Journal Bearings Considering Tangential Velocity Slip

1988 ◽  
Vol 110 (1) ◽  
pp. 139-143
Author(s):  
S. K. Guha ◽  
N. S. Rao ◽  
B. C. Majumdar
Keyword(s):  
Tangential Velocity ◽  
Hydrodynamic Pressure ◽  
Velocity Slip ◽  
Journal Bearings ◽  
Stability Characteristic ◽  
Damping Coefficients ◽  
Conical Whirl ◽  
Angular Displacements ◽  
Stiffness And Damping ◽  
Film Interface

The purpose of the present work is to study theoretically the conical whirl instability of unloaded self-acting porous gas journal bearings considering the tangential velocity slip at the bearing-film interface. The hydrodynamic pressure developed in the bearing clearance due to angular displacements of the journal at the midplane of the bearing is obtained by the simultaneous solution of equation of continuity in the porous medium and the modified Reynolds equations, satisfying the appropriate boundary conditions. With the help of the dynamic tilting stiffness and damping coefficients, stability characteristic is obtained. The effects of various parameters on conical stability parameter have been investigated for a nongyroscopic system.

Study of Conical Whirl Instability of Externally Pressurized Porous Oil Journal Bearings With Tangential Velocity Slip

1986 ◽  
Vol 108 (2) ◽  
pp. 256-261 ◽  
Author(s):  
S. K. Guha
Keyword(s):  
Tangential Velocity ◽  
Velocity Slip ◽  
Journal Bearings ◽  
Conical Whirl ◽  
Film Interface

In the present paper, an attempt has been made to study theoretically the conical whirl instability of unloaded hydrostatic porous oil journal bearings with tangential velocity slip on the bearing film interface. The effect of various parameters on stability has also been investigated.

Dynamic Characteristics of Finite Porous Journal Bearings Considering Tangential Velocity Slip

1984 ◽  
Vol 106 (4) ◽  
pp. 534-536 ◽  
Author(s):  
A. K. Chattopadhyay ◽  
B. C. Majumdar
Keyword(s):  
Theoretical Investigation ◽  
Finite Length ◽  
Dynamic Characteristics ◽  
Tangential Velocity ◽  
Velocity Slip ◽  
Journal Bearings ◽  
Film Interface

A theoretical investigation to find out the dynamic characteristics of porous journal bearings of finite length has been carried out considering the Beavers-Joseph crierion of velocity slip at the bearing film interface. It has been shown that the effect of velocity slip on the dynamic characteristics is small.

Stability of a Rigid Rotor in Finite Externally Pressurized Oil Journal Bearings With Slip

1987 ◽  
Vol 109 (2) ◽  
pp. 301-306 ◽  
Author(s):  
Ajit Kumar Chattopadhyay ◽  
B. C. Majumdar ◽  
N. S. Rao
Keyword(s):  
Theoretical Analysis ◽  
Finite Length ◽  
Tangential Velocity ◽  
Velocity Slip ◽  
Journal Bearings ◽  
Rigid Rotor ◽  
The Stability ◽  
Film Interface

A theoretical analysis has been carried out to determine the stability characteristics of externally pressurized porous oil journal bearings of finite length considering the tangential velocity slip at the bearing-film interface. The stability curves have been drawn for different slip parameters, eccentricity ratios, slenderness ratios, bearing speed parameters etc.

Steady-State and Dynamic Behaviour of Multi-Recess Hybrid Oil Journal Bearings

1979 ◽  
Vol 21 (5) ◽  
pp. 345-351 ◽  
Author(s):  
M. K. Ghosh ◽  
B. C. Majumdar ◽  
J. S. Rao
Keyword(s):  
Perturbation Theory ◽  
Steady State ◽  
Theoretical Analysis ◽  
Dynamic Behaviour ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Time Dependent ◽  
Damping Coefficients ◽  
Stiffness And Damping

A theoretical analysis of the steady-state and dynamic characteristics of multi-recess hybrid oil journal bearings is presented. A perturbation theory for small vibrations is used to solve an incompressible, finite journal bearing with a time-dependent term. Load capacity, attitude angle, friction parameter, stiffness and damping coefficients are evaluated for a capillary-compensated bearing.

On the linear stability analysis of finite-hydrodynamic porous journal bearings under coupled stress lubrication

2007 ◽  
Vol 221 (7) ◽  
pp. 831-840 ◽  
Author(s):  
S. K. Guha ◽  
A. K. Chattopadhyay
Keyword(s):  
Reynolds Equation ◽  
Dynamic Performance ◽  
Slip Flow ◽  
Tangential Velocity ◽  
Continuum Theory ◽  
Transient State ◽  
Velocity Slip ◽  
Journal Bearings ◽  
The Stability ◽  
Coupled Stress

The objective of the present investigation is to study theoretically, using the finite-difference techniques, the dynamic performance characteristics of finite-hydrodynamic porous journal bearings lubricated with coupled stress fluids. In the analysis based on the Stokes micro-continuum theory of the rheological effects of coupled stress fluids, a modified form of Reynolds equation governing the transient-state hydrodynamic film pressures in porous journal bearings with the effect of slip flow of coupled stress fluid as lubricant is obtained. Moreover, the tangential velocity slip at the surface of porous bush has been considered by using Beavers-Joseph criterion. Using the first-order perturbation of the modified Reynolds equation, the stability characteristics in terms of threshold stability parameter and whirl ratios are obtained for various parameters viz. permeability factor, slip coefficient, bearing feeding parameter, and eccentricity ratio. The results show that the coupled stress fluid exhibits better stability in comparison with Newtonian fluid.

An Experimental Investigation on the Static and Dynamic Characteristics of Journal Bearings Under the Influence of Twisting Misalignment

1997 ◽  
Vol 119 (1) ◽  
pp. 188-192 ◽  
Author(s):  
P. Arumugam ◽  
S. Swarnamani ◽  
B. S. Prabhu
Keyword(s):  
Finite Element Method ◽  
Vertical Direction ◽  
Journal Bearings ◽  
Response Functions ◽  
The Finite Element Method ◽  
Static And Dynamic Characteristics ◽  
Damping Coefficients ◽  
Stiffness And Damping ◽  
Different Levels ◽  
Bearing System

The misalignment between the journal and the bearing in a rotor-bearing system may be due to manufacturing error, elastic deflection, thermal expansion etc. In the present work, the eight linearized stiffness and damping coefficients of the cylindrical and three lobe bearings are identified at different levels of bearing misalignment (twisting misalignment) and at different speeds of the rotor. The identification method used here needs FRFs (Frequency Response Functions) obtained by the measurements and the finite element method. The twisting misalignment changes the stiffness and damping coefficients in the vertical and horizontal directions. In the case of three lobe bearings, for 0.7 degree of misalignment, the stiffness in the vertical direction is increased by about 12 percent.

A Derivation of Stiffness and Damping Coefficients for Short Hydrodynamic Journal Bearings with Pseudo-Plastic Lubricants

2020 ◽  
Vol 36 (6) ◽  
pp. 943-953
Author(s):  
Zhuxin Tian ◽  
Runchang Chen
Keyword(s):  
Perturbation Method ◽  
Small Perturbation ◽  
Integral Formula ◽  
Journal Bearings ◽  
Damping Coefficients ◽  
Non Linear ◽  
Small Perturbation Method ◽  
Plastic Lubricants ◽  
Factor Α ◽  
Stiffness And Damping

ABSTRACTA new derivation considering the non-linear terms has been proposed to calculate stiffness and damping coefficients for short hydrodynamic journal bearings lubricated with pseudo-plastic fluids. The proposed method has relaxed the constraint of small perturbation method applicable to only small values of non-Newtonian factor α. An analytical solution is also given. The non-linear Reynolds equation is solved with a more reasonable boundary condition ∂p*/∂z* = 0 at the location of z*=0 while the analytical pressure distribution is obtained by seven-point Gauss-Legendre integral formula. When the non-dimensional non-Newtonian factor α is small, the stiffness and damping coefficients of computed by the proposed method can agree well with those from small perturbation method, which could verify the proposed derivation. As for large non-dimensional non-Newtonian factor α, the stiffness coefficients $K_{XX}^*$ , $K_{XY}^*$ and $K_{YX}^*$ as well as the damping coefficients $C_{XX}^*$ , $C_{XY}^*$ and $C_{YX}^*$ decrease with the increasing of non-dimensional non-Newtonian factor α. The significance of the derivation is that it can relax the constraint of small α and simplify the computation process.

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