Influence of Turbulence on Performance Characteristics of the Tilting Pad Thrust Bearing

1974 ◽  
Vol 96 (1) ◽  
pp. 110-116 ◽  
Author(s):  
J. W. Capitao
Keyword(s):  
Turbulent Flow ◽  
Power Loss ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Equal Area ◽  
Thrust Bearings ◽  
Finite Difference Equations ◽  
Tilting Pad ◽  
Oil Flow ◽  
Flow Theories

The influence of fluid film turbulence on the performance of centrally-pivoted tilting pad thrust bearings was analyzed. Major features of the analysis are: (1) today’s two predominant “engineering” turbulent flow theories are delineated and their quantitative predictions compared; (2) a spherical pad profile was assumed, and (3) an equal area technique was used in the finite difference equations. The results confirmed earlier predictions of increases in power loss and load capacity when compared to a laminar solution. Also, no significant differences were found between the results predicted by the two predominant turbulent flow theories. Power loss, load capacity, and hydrodynamic oil flow are given for 13, 15, and 17 in. sizes. Comparisons of laminar and turbulent numerical results are presented.

The Influence of Ambient Pressure on the Measured Load Capacity of Bump-Foil and Spiral-Groove Gas Thrust Bearings at Ambient Pressures up to 69 Bar on a Novel High-Pressure Gas Bearing Test Rig

2019 ◽  
Author(s):  
Jason Wilkes ◽  
Ryan Cater ◽  
Erik Swanson ◽  
Kevin Passmore ◽  
Jerry Brady
Keyword(s):  
Power Loss ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Ambient Pressure ◽  
Spiral Groove ◽  
Test Rig ◽  
Thrust Bearings ◽  
Order Of Magnitude ◽  
Foil Thrust Bearing ◽  
Thrust Load

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.

A Comparison of Tilting Pad Thrust Bearing Lubricant Supply Methods

1983 ◽  
Vol 105 (1) ◽  
pp. 39-45 ◽  
Author(s):  
A. M. Mikula ◽  
R. S. Gregory
Keyword(s):  
Experimental Data ◽  
Power Loss ◽  
Thrust Bearing ◽  
Leading Edge ◽  
Potential User ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
Edge Distribution

This paper compares three different lubricant supply methods—pressurized supply (flooded), spray feed, and leading edge distribution groove—and analyzes their influence on the performance of tilting pad, equalizing thrust bearings. The paper presents experimental data on 267 mm (10-1/2 in.) o.d. bearings, operating at shaft speeds up to 13,000 rpm with loads ranging up to 3.45 MPa (500 psi). The data presented demonstrate the effect each lubricant supply method has on bearing power loss and temperature. Conclusions are drawn, based upon the effectiveness of each design, to guide the potential user.

scholarly journals On the Possibilities of Decreasing Power Loss in Large Tilting Pad Thrust Bearings

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Michal Wasilczuk ◽  
Grzegorz Rotta
Keyword(s):  
Power Loss ◽  
Power Plants ◽  
Thrust Bearing ◽  
Fluid Film ◽  
Total Power ◽  
Thrust Bearings ◽  
Oil Supply ◽  
Water Power ◽  
Lubricant Flow ◽  
Tilting Pad

Different systems of direct oil supply have been developed in order to facilitate efficient introduction of fresh lubricant to the oil gap and reduction of churning power loss in tilting pad thrust bearings. Up to now there is no documented application of the supply groove in large thrust bearings used in water power plants. The results of modeling lubricant flow in the lubricating groove of a thrust bearing pad will be presented in the paper. CFD software was used to carry out fluid film calculations. Such analysis makes it possible to modify groove geometry and other parameters and to study their influence on bearing performance. According to the results a remarkable decrease in total power loss due to avoiding churning losses can be observed in the bearing.

Rotordynamic and Bearing Upgrade of a High-Speed Turbocharger

2001 ◽  
Author(s):  
Brian C. Pettinato ◽  
Pranabesh DeChoudhury
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Flow Distribution ◽  
Journal Bearings ◽  
Original Design ◽  
Thrust Bearings ◽  
Vibration Data ◽  
Bearing Life ◽  
Oil Flow

The paper discusses the redesign of a high-speed turbocharger for improved bearing life and mechanical operation. The modifications resulted in reduced oil leakage across the end seal, reduced coke buildup at the turbine, increased thrust load capacity, and improved rotordynamics. In particular, rotordynamic stability was improved by eliminating subsynchronous vibration at the operating speed. The redesign consisted of changing the bearings from a pair of combination journal/thrust bearings to a pair of journal bearings and a double acting thrust bearing at the center of the unit. The active thrust bearing was moved away from the hot turbine end of the machine. The thrust bearing geometry was modified for increased minimum film thickness, reduced metal temperature, and increased load capacity. Inlet and drain passages were revised for better oil flow distribution. Unit rotordynamics were improved by upgrading the journal bearings from three-axial-groove to three-lobe design. The upgraded unit kept the same footprint as the original design with only piping modifications required. Extensive analysis and testing were conducted. Testing of the original and revised turbochargers showed improvements in the redesign with reduced bearing metal temperatures and improved rotordynamic stability. Theoretical results along with test data consisting of bearing performance and vibration data of the original and modified system are presented in this paper.

Effects of High-Operating Speeds on Tilting Pad Thrust Bearing Performance

1976 ◽  
Vol 98 (1) ◽  
pp. 73-79 ◽  
Author(s):  
J. W. Capitao ◽  
R. S. Gregory ◽  
R. P. Whitford
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Power Loss ◽  
High Speed ◽  
Thrust Bearing ◽  
Full Scale ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
Speed Performance ◽  
Bearing Loads

A comparison of the high-speed performance characteristics of tilting-pad, self-equalizing type thrust bearings through two independent full-scale programs is reported. This paper presents experimental data on centrally pivoted, 6-pad, 267-mm (10 1/2-in.) and 304-mm (12-in.) O.D. bearings operating at shaft speeds up to 14000 rpm and bearing loads ranging up to 2.76 MPa (400 psi). Data presented demonstrate the effects of speed and loading on bearing power loss and metal temperatures. Included is a discussion of optimum oil supply flow rate based upon considerations of bearing pad temperatures and power loss values.

The Leading-Edge-Groove Tilting-Pad Thrust Bearing: Recent Developments

1985 ◽  
Vol 107 (3) ◽  
pp. 423-428 ◽  
Author(s):  
A. M. Mikula
Keyword(s):  
Experimental Data ◽  
Power Loss ◽  
Thrust Bearing ◽  
Leading Edge ◽  
Thrust Bearings ◽  
Temperature Performance ◽  
Tilting Pad ◽  
Recent Developments ◽  
Bearing Design

This paper compares the leading edge groove and pressurized supply (flooded) lubricant supply methods, and analyzes their influence on the performance of equalizing tilting pad thrust bearings. This paper presents new experimental data on 6-shoe, 267 mm (10 1/2 in.) O.D. bearings, operating at shaft speeds up to 14000 rpm, with loads ranging up to 3.45 MPa (500 psi) for two different lubricants. The data presented details the power loss and babbitt temperature performance of two versions of the leading-edge-groove bearing design and contrasts the results with a pressurized supply bearing design.

Computation of Thermal Deformation of Thrust Bearing Pad Concerning the Convection by Non-Uniform Oil Flow

2005 ◽  
Author(s):  
Makoto Hemmi ◽  
Koushu Hagiya ◽  
Katsuhisa Ichisawa ◽  
Sukeyuki Fujita
Keyword(s):  
Temperature Distribution ◽  
Thermal Deformation ◽  
Thrust Bearing ◽  
Oil Film ◽  
Thrust Bearings ◽  
Turbine Generators ◽  
Precise Estimation ◽  
Tilting Pad ◽  
Oil Flow ◽  
Water Turbine

Tilting-pad thrust bearings are used to support the loads of large rotating machinery, such as water turbine generators. When such machines are in operation, thermal deformation is so extensive that it is comparable to deformation caused by the pressure of the oil film, and it influences the bearing’s performance. So, the temperature distribution in the pad, which determines the thermal deformation, should be calculated correctly. This requires precise estimation of the convection by the ambient oil at the pad’s surfaces, but the complexity of the pad’s shape and ambient oil flow of oil around it makes this estimation difficult. Using CFD (Computational Fluid Dynamics) software, we computed the temperature distribution in the pad by solving the heat transfer in the pad, in the oil and interfaces of them simultaneously. The thermal and stress deformation were then calculated by the FEM code and is used in oil film analysis to determine the characteristics of the bearing. Comparing its results with the experimental ones validated the computational process.

The Steady-State Characteristics of a Hydrostatic Thrust Bearing With a Floating Disk

1989 ◽  
Vol 111 (2) ◽  
pp. 352-357
Author(s):  
M. Harada ◽  
J. Tsukazaki
Keyword(s):  
Steady State ◽  
Rotational Speed ◽  
Power Loss ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Frictional Torque ◽  
Thrust Bearings ◽  
Stable Position ◽  
Surface Configuration

To reduce the frictional power loss of hydrostatic thrust bearings, the hydrostatic thrust bearing with a floating disk shaped in a simplified configuration is proposed. And the load capacity and the frictional torque are experimentally investigated in laminar and superlaminar regimes. Following results can be obtained: (1) The disk floats at a certain stable position for given shaft rotational speed and rotates at nearly half rotational speed of the shaft. (2) The frictional torque of this type of the bearing is less than half of a conventional hydrostatic thrust bearing with the same surface configuration as the floating disk.

Performance of Thrust Bearings at High Operating Speeds

1974 ◽  
Vol 96 (1) ◽  
pp. 7-13 ◽  
Author(s):  
R. S. Gregory
Keyword(s):  
Research Program ◽  
Feed Rate ◽  
Power Loss ◽  
Thrust Bearing ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Laminar To Turbulent Transition ◽  
Turbulent Transition ◽  
Tilting Pad ◽  
Bearing Loads

As part of a continuing research program, a standard 10 1/2 in. dia thrust bearing, of the tilting-pad, self-equalizing type, was tested at shaft speeds up to 11,000 rpm and bearing loads ranging up to 400 psi. The bearing and lube oil system were instrumented to measure bearing performance under laminar and turbulent operating conditions. The effects of varying the oil feed rate on bearing temperature and power loss are discussed in this paper. Some observations on the laminar to turbulent transition region are included.

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