Evaluating Thermal Performance of a PTFE-Faced Tilting Pad Thrust Bearing

2003 ◽  
Vol 125 (2) ◽  
pp. 319-324 ◽  
Author(s):  
Sergei B. Glavatskih
Keyword(s):  
Thrust Bearing ◽  
Friction Torque ◽  
Outer Diameter ◽  
Test Results ◽  
Operating Characteristics ◽  
Thrust Bearings ◽  
Ptfe Composite ◽  
Temperature Distributions ◽  
Tilting Pad ◽  
Bearing Friction

This paper compares and analyses operating characteristics of equalizing tilting pad thrust bearings with babbitt and polytetrafluoroethylene (PTFE) composite facings. Each bearing arrangement included six pads with an outer diameter of 228.6 mm and 60 percent offset. The babbitted bearing was typical of design in general use. A PTFE composite was applied instead of the babbitt to a similar bearing. Bearings were tested at different load-speed combinations in the fully flooded mode. Pad temperature distributions, collar temperatures and bearing friction torque were continuously measured. Test results show that the PTFE composite provides excellent thermal insulation so that pad thermal crowning is eliminated. PTFE-faced bearings operate with lower power loss and slightly higher collar temperatures compared to similar babbitted bearings.

The Significance of Oil Thermal Properties on the Performance of a Tilting-Pad Thrust Bearing

2001 ◽  
Vol 124 (2) ◽  
pp. 377-385 ◽  
Author(s):  
Sergei B. Glavatskih ◽  
Michel Fillon ◽  
Roland Larsson
Keyword(s):  
Thermal Properties ◽  
Film Thickness ◽  
Thrust Bearing ◽  
Friction Torque ◽  
Temperature Fields ◽  
Outer Diameter ◽  
Oil Film ◽  
Tilting Pad ◽  
Viscosity Grade ◽  
Mineral Base

This paper is a report into an experimental and theoretical investigation of the effect of oil thermal properties on the performance of a tilting-pad thrust bearing. Three oils, namely poly-α-olefin, ester and mineral base, were chosen for this study. These oils all have same viscosity grade (ISO VG46) but differ in their rates of viscosity variation with temperature and in their heat capacity and thermal conductivity values. Mineral base oil of a higher viscosity grade (ISO VG68) was also analyzed for comparison. Experimental data were obtained from an equalizing tilting-pad thrust bearing with an outer diameter of 228.6 mm operating in a flooded lubrication mode. Simultaneous measurements of pad and collar temperatures, friction torque, pressures and oil film thickness were taken. In the tests, oil supply temperature and flow rate were held constant for all load-speed combinations. The theoretical analysis of oil performance was based on a three-dimensional TEHD model. In the analysis, thermal effects were locally taken into account and heat transfer into the pads was considered. The displacements of the active surface of the pads, due to pressure and temperature fields, were determined. The effect of initial pad crowning on the oil film thickness is discussed. Experimental and theoretical results are compared and analyzed in terms of the inlet and outlet oil film thickness, bearing operating temperature and power loss.

Performance Characteristics of Tilting Pad Thrust Bearings at High Operating Speeds

1976 ◽  
Vol 98 (1) ◽  
pp. 81-88 ◽  
Author(s):  
J. W. Capitao
Keyword(s):  
Power Loss ◽  
Thrust Bearing ◽  
Experimental Program ◽  
Test Results ◽  
Transition Range ◽  
Thrust Bearings ◽  
Laminar To Turbulent Transition ◽  
Turbulent Transition ◽  
Tilting Pad ◽  
Bearing Loads

A full scale experimental program was conducted to investigate the influence of fluid film turbulence on the performance of the tilting-pad, self-equalizing type thrust bearing. Test results include data on centrally pivoted, 6-pad, 381-mm (15-in.) and 432-mm (17-in.) O.D. bearings operating with shaft speeds up to 10000 rpm and bearing loads ranging up to 3.447 MPa (500 psi). Data collected include bearing metal temperatures, bearing power loss, and observation of the laminar to turbulent transition range.

Turbulent Lubrication of Tilting-Pad Thrust Bearings With Thermal and Elastic Deformations

1985 ◽  
Vol 107 (1) ◽  
pp. 82-86 ◽  
Author(s):  
H. Hashimoto ◽  
S. Wada
Keyword(s):  
Friction Torque ◽  
Shaft Speed ◽  
Centrifugal Forces ◽  
Balance Equations ◽  
Elastic Deformations ◽  
Film Pressure ◽  
Thrust Bearings ◽  
Temperature Distributions ◽  
Tilting Pad ◽  
Energy Equations

Pad deformations of sector-shaped, tilting-pad thrust bearings affecting turbulent lubrication are discussed theoretically. Solving the lubrication and energy equations with turbulence and centrifugal forces and the elastic and moment balance equations of a pad simultaneously, film pressure and temperature distributions, thermal and elastic deformations and inclinations of a pad are obtained. Film thicknesses at a pivot under a constant shaft speed become larger due to pad deformations, whereby pad inclinations increase and friction torque coefficients decrease outstandingly. It is important to introduce the effects of pad deformations when analysing performances of such bearings running in the turbulent conditions.

Performance Tests on Six-Inch Tilting Pad Thrust Bearings

1975 ◽  
Vol 97 (3) ◽  
pp. 430-436 ◽  
Author(s):  
W. W. Gardner
Keyword(s):  
Laboratory Tests ◽  
Performance Tests ◽  
Operating Characteristics ◽  
Thrust Bearings ◽  
Backing Material ◽  
Tilting Pad

Laboratory tests were conducted on six-in-dia tilting pad thrust bearings to compare operating characteristics of several pad facing and backing material combinations and also to study the effects of different oil feed and discharge arrangements. Tests were conducted at various speeds and loadings, including a series of failure tests. Results of these tests are presented.

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.

Performance of Elastic, Centrally Pivoted, Sector, Thrust-Bearing Pads—Part I

1961 ◽  
Vol 83 (2) ◽  
pp. 169-178 ◽  
Author(s):  
B. Sternlicht ◽  
J. C. Reid ◽  
E. B. Arwas
Keyword(s):  
Experimental Data ◽  
Approximate Calculation ◽  
Thrust Bearing ◽  
Full Scale ◽  
Fluid Film ◽  
Thermal Gradients ◽  
Thrust Bearings ◽  
Adiabatic Conditions ◽  
Tilting Pad

This is the first of three papers on the results of a recently completed study of the performance of tilting pad thrust bearings. It describes a method of analysis that was worked out for these bearings, which includes viscosity variations in the fluid film and an approximate calculation of the pad deflections caused by the hydrodynamic pressures. Equilibrium of moments is satisfied, laminar and adiabatic conditions are assumed, and the lubricant is incompressible. The two subsequent papers of this series will describe: (a) The results of an analysis which includes a more rigorous determination of pad deflections caused by hydrodynamic pressures and thermal gradients. (b) A comparison of analytical results with experimental data obtained in full-scale bearing tests.

PROSPECTS OF DECREASING POWER LOSSES IN A HYDROSTATIC THRUST BEARING

Tribologia ◽  
2017 ◽  
pp. 91-96 ◽  
Author(s):  
Filip WASILCZUK ◽  
Michał WASILCZUK ◽  
Michał WODTKE
Keyword(s):  
Fluid Dynamics ◽  
Axial Load ◽  
Thrust Bearing ◽  
Power Losses ◽  
Important Goal ◽  
Hydrodynamic Bearing ◽  
Thrust Bearings ◽  
Hydrostatic Bearing ◽  
Tilting Pad ◽  
Contemporary Technology

In numerous machines, axial load is carried by tilting pad thrust bearings known since the beginning of 20th century. These bearings are commonly bath lubricated, which is simple, does not require any additional pumps, and, due to this, such systems are highly reliable. In a contemporary technology, however, minimization of friction losses became an important goal of machinery improvement. Calculations based on elementary rules of fluid dynamics show that shearing losses in a specially designed hydrostatic bearing can be considerably smaller than the losses in a tilting pad hydrodynamic bearing. The aim of the research described in this paper was to check if the preliminary results can also be confirmed with the use of more advanced CFD calculations.

An Optimum Design Approach for Textured Thrust Bearing With Elliptical-Shape Dimples Using CFD and DOE Including Cavitation

2016 ◽  
Author(s):  
Gen Fu ◽  
Alexandrina Untaroiu
Keyword(s):  
Reynolds Equation ◽  
Thrust Bearing ◽  
Major Axis ◽  
Friction Torque ◽  
Load Force ◽  
Surface Model ◽  
Temperature Threshold ◽  
Optimization Approach ◽  
Loading Capacity ◽  
Thrust Bearings

Surface texturing has been used to enhance contact performance for decades since 1960s. Surface structures can tremendously change the friction coefficient of the contact surface. These structures have been widely used in bearings and seals. According to previous studies, textured thrust bearings provide more loading capacity than non-textured bearings. Compared to tapered and step bearings, the dimples can also reduce the friction torque. However, most previous optimization efforts for texturing geometry were focused on rectangular dimples and employed Reynolds equation. Limited studies have been done to investigate the effects of partially textured thrust bearings with elliptical dimples. This study proposes a new optimization approach to find the optimal partially texture geometry with elliptical dimples, which maximize the loading capacity and minimize the friction torque. In this study, a 3D computational fluid dynamics model for a parallel sector-pad thrust bearing is built using ANSYS CFX software instead of solving Reynolds equation with simplified field assumptions. Only one sector of the thrust bearing is modeled. Mass conserving cavitation model is used to simulate the cavitation region inside the dimples. Energy equation for Newtonian flow is also solved. Realistic boundary conditions are applied. The results of the model are validated by the experimental data from the literature. Based on this model, the flow pattern and pressure distribution inside the dimples are analyzed. Then, the geometry of elliptical dimple is parameterized and analyzed using the method of design of experiments (DOE). In this study, all the dimples have identical geometry. The selected geometry parameters include the length of major axis, the length of minor axis, dimple depth, circumferential space between two dimples, radial space between two dimples, radial extend and circumferential extend. The design space is sampled using central composite method. A temperature threshold is set to exclude the design points which result in high temperatures. A quadratic response surface model is created based on the results of the DOE process. Next, a multi-objective optimization scheme is used to find the optimal texture structure with the load force and friction torque set as objective functions. The results show that the shape of dimples has a crucial effect on the performance of the textured thrust bearings. This optimization approach proposed is expected to be useful in typical texture design process of thrust bearing.

Analysis and Test of a Robust Sector Thrust Bearing for a Cryogenic Turboalternator

2001 ◽  
Vol 123 (4) ◽  
pp. 768-776
Author(s):  
G. F. Nellis ◽  
M. V. Zagarola ◽  
H. Sixsmith
Keyword(s):  
Thrust Bearing ◽  
Large Temperature ◽  
Cryogenic Temperatures ◽  
Inertial Effects ◽  
Test Results ◽  
Viscous Effects ◽  
Reliable Operation ◽  
Restoring Force ◽  
Thrust Bearings ◽  
Leakage Flows

The miniature turboalternator associated with a reverse-Brayton cryocooler requires geometrically simple, self-acting thrust bearings capable of reliable operation over a large temperature range and insensitive to secondary leakage flows. In order to meet this need, a robust sector thrust bearing has been developed. This thrust bearing is different from a classic stepped sector thrust bearing in that the restoring force at cryogenic temperatures originates primarily from inertial effects while at higher temperatures its restoring force is related primarily to viscous effects. This paper describes the analysis and initial test results for a prototypical robust sector thrust bearing.

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.

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