Performance of Lightly Loaded Gas Journal Bearings in the Slip-Flow and Turbulent-Flow Regimes

1968 ◽  
Vol 10 (4) ◽  
pp. 363-366
Author(s):  
M. D. Wood
Keyword(s):  
Steady State ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Reynolds Equation ◽  
Dynamic Performance ◽  
Slip Flow ◽  
Flow Regimes ◽  
Journal Bearings ◽  
Performance Parameters ◽  
Existing Data

The note compares recently published versions of the governing gas film equations for slip-flow and turbulent flow with Reynolds equation for laminar flow. The comparison shows how approximate values of steady-state and dynamic performance parameters may be deduced for the new conditions from existing data.

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.

Static characteristics of hydrostatic doubled-layered porous journal bearings with slip flow including additives percolation into pores under coupled stress lubrication

2017 ◽  
Vol 232 (8) ◽  
pp. 927-939 ◽  
Author(s):  
Shitendu Some ◽  
Sisir K Guha
Keyword(s):  
Steady State ◽  
Reynolds Equation ◽  
Slip Flow ◽  
Journal Bearings ◽  
Static Characteristics ◽  
Governing Equations ◽  
Modified Reynolds Equation ◽  
Film Interface ◽  
Coupled Stress ◽  
Steady State Performance

A theoretical analysis of the steady-state characteristics of finite hydrostatic double-layered porous journal bearings dealing with the effects of slip flow at the fine porous layer–film interface and percolation of additives into pores under the coupled stress fluid lubrication is presented. Based on the Beavers–Joseph’s criterion for slip flow, the modified Reynolds equation applicable to finite porous journal bearings lubricated with coupled stress fluids have been derived. The governing equations for flow in the coarse and fine layers of porous medium incorporating the percolation of polar additives of lubricant and the modified Reynolds equation are solved simultaneously using finite difference method satisfying appropriate boundary conditions to obtain the steady-state performance characteristics for various parameter namely percolation factor, slip coefficient, bearing feeding parameter, coupled stress parameter, and eccentricity ratio. The results are exhibited in the form of graphs, which may be useful for design of such bearing.

The Effect of Lubricant Inertia in Journal-Bearing Lubrication

1957 ◽  
Vol 24 (4) ◽  
pp. 494-496
Author(s):  
J. F. Osterle ◽  
Y. T. Chou ◽  
E. A. Saibel
Keyword(s):  
Reynolds Number ◽  
Steady State ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Hydrodynamic Theory ◽  
Simple Relationship ◽  
Inertia Effect ◽  
Laminar Regime ◽  
Steady State Operation

Abstract The Reynolds equation of hydrodynamic theory, modified to take lubricant inertia into approximate account, is applied to the steady-state operation of journal bearings to determine the effect of lubricant inertia on the pressure developed in the lubricant. A simple relationship results, relating this “inertial” pressure to the Reynolds number of the flow. It is found that the inertia effect can be significant in the laminar regime.

scholarly journals Effect of Dam Depth and Relief Track Depth on Steady-State and Dynamic Performance Parameters of 3-Lobe Pressure Dam Bearing

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ashutosh Kumar ◽  
S. K. Kakoty
Keyword(s):  
Steady State ◽  
Dynamic Performance ◽  
Performance Characteristics ◽  
Performance Parameters ◽  
Effect Of Pressure ◽  
And Performance

The present study analyzes the effect of pressure dam depth and relief track depth on the performance of three-lobe pressure dam bearing. Different values of dam depth and relief track depth are taken in nondimensional form in order to analyze their effect. Results are plotted for different parameters against eccentricity ratios and it is shown that the effect of pressure dam depth and relief track depth has great significance on stability and other performance parameters. Study of stability and performance characteristics is undertaken simultaneously.

On The Steady State and Dynamic Performance Characteristics of Floating Ring Bearings

1981 ◽  
Vol 103 (3) ◽  
pp. 389-397 ◽  
Author(s):  
Chin-Hsiu Li ◽  
S. M. Rohde
Keyword(s):  
Steady State ◽  
Linear Theory ◽  
High Speed ◽  
Dynamic Performance ◽  
Equations Of Motion ◽  
Nonlinear Behavior ◽  
Journal Bearings ◽  
Transient Problem ◽  
The Stability ◽  
Bearing System

An analysis of the steady state and dynamic characteristics of floating ring journal bearings has been performed. The stability characteristics of the bearing, based on linear theory, are given. The transient problem, in which the equations of motion for the bearing system are integrated in real time was studied. The effect of using finite bearing theory rather than the short bearing assumption was examined. Among the significant findings of this study is the existence of limit cycles in the regions of instability predicted by linear theory. Such results explain the superior stability characteristics of the floating ring bearing in high speed applications. An understanding of this nonlinear behavior, serves as the basis for new and rational criteria for the design of floating ring bearings.

Effect of couple stress parameter on steady-state and dynamic characteristics of three-lobe journal bearing operating on TiO2 nanolubricant

2019 ◽  
Vol 234 (4) ◽  
pp. 528-540
Author(s):  
Ashutosh Kumar ◽  
SK Kakoty
Keyword(s):  
Steady State ◽  
Couple Stress ◽  
Volume Fraction ◽  
Dynamic Performance ◽  
Significant Rise ◽  
Flow Coefficient ◽  
Performance Parameters ◽  
Stress Parameter ◽  
Load Carrying ◽  
Stiffness And Damping

Steady-state and dynamic performance parameters of three-lobe fluid film bearing, operating on TiO2 nanolubricant have been obtained. The effective viscosity for a given volume fraction of TiO2 nanoparticle in base fluid is obtained by using Krieger–Dougherty viscosity model. Various bearing performance parameters are obtained by solving remodeled Reynolds equation, which includes couple stress parameter. The stiffness and damping coefficients are also obtained for different values of the couple stress parameter. Results show a significant rise in the nondimensional load-carrying capacity and flow coefficient while there is a decrease in friction variable. It also reveals a significant improvement in the dynamic coefficient of bearing.

Rotor-dynamic performance of porous hydrostatic thrust bearing operating under magnetic field

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vivek Kumar ◽  
Vatsalkumar Ashokkumar Shah ◽  
Simran Jeet Singh ◽  
Kuldeep Narwat ◽  
Satish C. Sharma
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Steady State ◽  
Magnetic Fluid ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Dynamic Performance ◽  
Performance Indices ◽  
Content Type ◽  
Rotor Dynamic

Purpose The porous bearings are commonly used in slider thrust bearings owing to their self-lubricating properties and cost effectiveness as compared to conventional hydrodynamic bearings. The purpose of this paper is to numerically investigate usefulness of porous layer in hydrostatic thrust bearing operating with magnetic fluid. The effect of magnetic field and permeability has been analysed on steady-state (film pressure, film reaction and lubricant flow rate) and rotor-dynamic (stiffness and damping) parameters of bearing. Design/methodology/approach Finite element approach is used to obtain numerical solution of flow governing equations (Magneto-hydrodynamics Reynolds equation, Darcy law and capillary equation) for computing abovementioned performance indices. Finite element method formulation converts elliptical Reynolds equation into set of algebraic equation that are solved using Gauss–Seidel method. Findings It has been reported that porosity has limited but adverse effects on performance parameters of bearing. The adverse effects of porosity can be minimized by using a circular pocket for achieving better steady-state response and an annular/elliptical pocket, for having better rotor-dynamic response. The use of magnetic fluid is found to be substantially enhancing the fluid film reaction (53%) and damping parameters (55%). Practical implications The present work recommends use of circular pocket for achieving better steady-state performance indices. However, annular and elliptical pockets should be preferred, when design criteria for the bearing are better rotor-dynamic performance. Originality/value This study deals with influence of magnetic fluid, porosity and pocket shape on rotor-dynamic performance of externally pressurized thrust bearing. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0289/

The Steady-State and Dynamic Characteristics of a Full Circular Bearing and a Partial Arc Bearing in the Laminar and Turbulent Flow Regimes

1967 ◽  
Vol 89 (2) ◽  
pp. 143-153 ◽  
Author(s):  
F. K. Orcutt ◽  
E. B. Arwas
Keyword(s):  
Steady State ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Flow Regime ◽  
Dynamic Characteristics ◽  
Reynolds Numbers ◽  
Operating Parameters ◽  
Design Data ◽  
Design Charts ◽  
Laminar And Turbulent Flow

The steady-state and dynamic characteristics of a full circular bearing and a centrally loaded, 100 deg, arc bearing are calculated for a range of eccentricity ratios to 0.95 and of mean Reynolds numbers to 13,300, and presented in design charts. These are compared with the measured performance of these bearings over the same ranges of the operating parameters. There is good correlation between the theoretical and test data, leading to the conclusion that the present turbulent lubrication analysis may be used to obtain general design data for self-acting bearings, operating in the superlaminar flow regime, to supplement that presently existing for laminar flow bearings.

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