Numerical Analysis of the Gas-Lubricated Spiral-Groove Thrust Bearing-Compressor

1967 ◽  
Vol 89 (4) ◽  
pp. 439-443 ◽  
Author(s):  
D. D. James ◽  
A. F. Potter

The isothermal Reynolds differential equation of gas film lubrication is written in finite-difference form for numerical analysis of the pressure distribution within spiral-groove thrust bearings and compressors. Appropriate jump equations are presented which provide flow continuity at the land-to-groove interfaces. Gas flow, load support, static stiffness, power consumption, and compressor efficiency are computed and theoretical performance curves are presented for this device. Agreement between computed data and experiment is discussed and presented in graphical form.

1950 ◽  
Vol 163 (1) ◽  
pp. 149-161 ◽  
Author(s):  
M. E. Salama

This work was initiated to investigate the effect of surface macro-roughness on the performance of the parallel-faces thrust bearing and, at the same time, to find a rational explanation of its behaviour. The problem is treated both theoretically and experimentally and the main result arrived at indicates that macro-roughness is a prime factor in the behaviour of the bearing, as it provides passages which both feed the surfaces with the lubricant and allow the formation of hydrodynamic films so that the performance corresponds closer to that for film lubrication. Further work on micro-roughness is proceeding.


Author(s):  
Jason Wilkes ◽  
Ryan Cater ◽  
Erik Swanson ◽  
Kevin Passmore ◽  
Jerry Brady

Abstract This paper will show the influence of ambient pressure on the thrust capacity of bump-foil and spiral-groove gas thrust bearings. The bearings were operating in nitrogen at various pressures up to 69 bar, and were tested to failure. Failure was detected at various pressures by incrementally increasing the thrust load applied to the thrust bearing until the bearing was no longer thermally stable, or until contact was observed by a temperature spike measured by thermocouples within the bearing. These tests were performed on a novel thrust bearing test rig that was developed to allow thrust testing at pressures up to 207 bar cavity pressure at 260°C while rotating at speeds up to 120,000 rpm. The test rig floats on hydrostatic air bearings to allow for the direct measurement of applied thrust load through linkages that connect the stationary thrust loader to the rotor housing. Test results on a 65 mm (2.56 in) bump-foil thrust bearing at 100 krpm show a marked increase in load capacity with gas density, which has not previously been shown experimentally. Results also show that the load capacity of a similarly sized spiral-groove thrust bearing are relatively insensitive to pressure, and supported an order-of-magnitude less load than that observed for the bump-foil thrust bearing. These results are compared with analytical predictions, which agree reasonably with the experimental results. Predicted power loss is also presented for the bump-foil bearing; however, measured power loss was substantially higher.


2013 ◽  
Vol 694-697 ◽  
pp. 538-542 ◽  
Author(s):  
Xiao Yan Liu ◽  
Jia Sheng Wang

The water lubrication performance of spiral groove thrust bearings was affected by different groove molded lines. The pressure fields and the load capacity of water-lubricated spiral groove thrust bearings with different groove molded lines were simulated by computational fluid dynamics. The results show that the spiral groove which can produce the best loading capacity and steadier pressure field is appropriate to water-lubricated spiral groove thrust bearing. The line spiral groove can be used for decrease the process difficult when the loading capacity require is low.


Author(s):  
K C Singh ◽  
N S Rao ◽  
B C Majumdar

A theoretical analysis is presented to predict the static axial performance characteristics of a porous circular thrust bearing with a central hole for both open and sealed ends, taking into consideration the tilt of the runner pad. The flow in the bearing matrix is considered to be three-dimensional. The governing equations of gas flow through the porous pad and the bearing clearance are solved simultaneously using the finite difference technique to obtain pressure distribution in the bearing clearance. The load capacity, mass rate of flow and static axial stiffness are calculated numerically for various bearing dimensions and supply conditions and presented in graphical form. The bearings with sealed ends have comparatively better load capacity over those with unsealed ends. The effect of tilt is to decrease the load capacity and increase the mass flowrate.


Author(s):  
Aaron M. Rimpel ◽  
Giuseppe Vannini ◽  
Jongsoo Kim

A high speed gas bearing test rig was developed to characterize rotordynamic, thermal, and thrust load performance of gas bearings being developed for an oil-free turboexpander. The radial bearings tested in this paper were tilting pad journal bearings with radial compliance features that allow the bearing bore to increase to accommodate shaft growth, and the thrust bearings were a spiral groove type with axial compliance features. The thrust bearing accounts for over 90% of the combined bearing power consumption, which has a cubic relationship with speed and increases with case pressure. Radial bearing circumferential pad temperature gradients increased approximately with speed to the fourth or fifth power, with slightly higher temperature rise for lower case pressure. Maximum steady state bearing pad temperatures increase with increasing speed for similar cooling mass flow rates; however, only the thrust bearing showed a significant increase in temperature with higher case pressure. The thrust bearings were stable at all speeds, but the load capacity was found to be lower than anticipated, apparently due to pad deformations caused by radial temperature gradients in the stator. More advanced modeling approaches have been proposed to better understand the thrust bearing thermal behavior and to improve the thrust bearing design. Finally, the radial bearings tested were demonstrated to be stable up to the design speed of 130 krpm, which represents the highest surface speed for tilting pad gas bearings tested in the literature.


1971 ◽  
Vol 93 (1) ◽  
pp. 102-111 ◽  
Author(s):  
C. Wachmann ◽  
S. B. Malanoski ◽  
J. H. Vohr

Self-heating during operation causes a bearing to undergo thermal distortion. A method is presented to determine the consequent effects on the load capacity of a spiral-grooved air-lubricated thrust bearing designed for maximum load capacity. The effect of mode of heat removal is discussed. Appropriate performance curves and a worked example are given.


2014 ◽  
Vol 541-542 ◽  
pp. 658-662
Author(s):  
Jian Li ◽  
Yuan Chen ◽  
Yang Chun Yu ◽  
Zhu Xin Tian ◽  
Yu Huang

To study the velocity and pressure distribution of the oil film in a heavy hydrostatic thrust bearing, a mathematical model of the velocity is proposed and the finite volume method (FVM) has been used to simulate the flow field under different working conditions. Some pressure experiments were carried out and the results verified the correctness of the simulation. It is concluded that the pressure distribution varies small under different rotation speed when the surface load on the workbench is constant. But the velocity of the oil film is influenced greatly by the rotation speed. When the rotation speed of the workbench is as quick as enough, the velocity of the oil film on one radial side of the pad will be zero, that is to say the lubrication oil will be drained from the other three sides of the recess.


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