THD Analysis of Tilting Pad Thrust Bearings—Comparison Between Theory and Experiments

1999 ◽  
Vol 122 (2) ◽  
pp. 412-417 ◽  
Author(s):  
T. Almqvist ◽  
S. B. Glavatskikh ◽  
R. Larsson
Keyword(s):  
Three Dimensional ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Transfer Coefficients ◽  
Thrust Bearings ◽  
Heat Transfer Coefficients ◽  
Pressure Profiles ◽  
Tilting Pad ◽  
Temperature And Pressure ◽  
Theory And Experiments

The objective of the present research is to verify a THD model of hydrodynamic thrust bearings. The developed model of a pivoted pad bearing, which can tilt both radially and circumferentially, allows for three-dimensional temperature distribution in the oil film and in the pad, as well as two-dimensional temperature variation in the runner. Viscosity and density are treated as functions of both temperature and pressure. Experiments have been performed on a test rig, containing two identical equalizing pivoted pad thrust bearings. Power loss, runner temperature, and pressure profiles as a function of load and rotational speed are compared for both theoretical and experimental investigations. Fairly good agreement has been found when the oil inlet temperature and heat transfer coefficients have been estimated in order to get the same runner temperature in both theory and experiment. [S0742-4787(00)00802-X]

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings—Part I: Theory

2007 ◽  
Vol 129 (4) ◽  
pp. 895-903 ◽  
Author(s):  
Niels Heinrichson ◽  
Ilmar Ferreira Santos ◽  
Axel Fuerst
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Pressure Injection ◽  
Pressure Profiles ◽  
Tilting Pad ◽  
Oil Injection ◽  
High Pressure Injection ◽  
Theoretical Results

This is Part I of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. In Part I a numerical model based on the Reynolds equation is developed extending the three-dimensional thermoelastohydrodynamic (TEHD) analysis of tilting-pad thrust bearings to include the effects of high-pressure injection and recesses in the bearing pads. The model is applied to the analysis of an existing bearing of large dimensions and the influence of the pocket is analyzed. In the analysis, the high-pressure oil injection used for hydrostatic jacking is turned off (i.e., only the effect of the pocket is studied). It is shown that a shallow pocket positively influences the performance of the bearing because it has characteristics similar to those of a Rayleigh-step bearing. In Part II of the paper (Heinrichson, N., Fuerst, A., and Santos, I. F., 2007, ASME J. Tribol., 129(4), pp. 904–912) measurements of pressure profiles and oil film thickness for a test-pad are compared to theoretical results. The analysis of Part II deals both with flow situations, where the high-pressure injection is turned off, as well as with situations where it is turned on for hydrostatic jacking.

Numerical simulations for the fluid-thermal-structural interaction lubrication in a tilting pad thrust bearing

2017 ◽  
Vol 34 (4) ◽  
pp. 1149-1165 ◽  
Author(s):  
Liming Zhai ◽  
Yongyao Luo ◽  
Xin Liu ◽  
Funan Chen ◽  
Yexiang Xiao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Rotational Speed ◽  
Thrust Bearing ◽  
Transfer Coefficients ◽  
Content Type ◽  
Thrust Bearings ◽  
Heat Transfer Coefficients ◽  
Tilting Pad ◽  
Lubrication Characteristics ◽  
Thrust Load

Purpose The purpose of this paper is to analyze lubrication characteristics of a tilting pad thrust bearing considering the effect of the thermal elastic deformation of the pad and collar. Design/methodology/approach This study used the fluid–solid interaction (FSI) technique to investigate the lubrication characteristics of a tilting pad thrust bearing for several typical operating conditions. The influences of the rotational speed, the thrust load and the oil supply temperature on the lubrication characteristics were analyzed. Findings The three-dimensional (3D) film model clearly shows that there is no pressure gradient but large temperature gradients across the film thickness. The wall heat transfer coefficients on the pad surfaces distribute in a very complex way and change within a large range. The rotational speed, the thrust load and the oil supply temperature have great but different influences on the lubrication characteristics. Originality/value This paper has preliminarily revealed the lubrication mechanism of the tilting-pad thrust bearings. The 3D FSI method is suggested to evaluate the thermal-elastic-hydrodynamic deformations of thrust bearings instead of the conventional method which iteratively solves the Reynolds equation, the energy equation, the heat conduction equation and the elastic equilibrium equation. Using FSI method, the heat transfer coefficients on the pad surfaces can be evaluated better.

scholarly journals Condensation inside smooth horizontal tubes: Part 1. Survey of the methods of heat-exchange prediction

2015 ◽  
Vol 19 (5) ◽  
pp. 1769-1789 ◽  
Author(s):  
Volodymyr Rifert ◽  
Volodymyr Sereda
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Film Condensation ◽  
Experimental Investigations ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes

Survey of the works on condensation inside smooth horizontal tubes published from 1955 to 2013 has been performed. Theoretical and experimental investigations, as well as more than 25 methods and correlations for heat transfer prediction are considered. It is shown that accuracy of this prediction depends on the accuracy of volumetric vapor content and pressure drop at the interphase. The necessity of new studies concerning both local heat transfer coefficients and film condensation along tube perimeter and length under annular, stratified and intermediate regimes of phase flow was substantiated. These characteristics being defined will allow determining more precisely the boundaries of the flow regimes and the methods of heat transfer prediction.

A Three-Dimensional Analysis of Thermohydrodynamic Performance of Sector-Shaped, Tilting-Pad Thrust Bearings

1983 ◽  
Vol 105 (3) ◽  
pp. 406-412 ◽  
Author(s):  
Kyung Woong Kim ◽  
Masato Tanaka ◽  
Yukio Hori
Keyword(s):  
Dimensional Analysis ◽  
Environmental Conditions ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
Dimensional Variation ◽  
Lubricant Viscosity

The thermohydrodynamic performance of the bearing is analyzed, taking into account the three-dimensional variation of lubricant viscosity and density. The effect of pivot position and operating and environmental conditions on the performance is studied. The present analysis is compared with the isoviscous or the two-dimensional analysis, and is found to predict the bearing performance more accurately.

scholarly journals Cooled Pads for Tilting-Pad Journal Bearings

Lubricants ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 92
Author(s):  
Steven Chatterton ◽  
Paolo Pennacchi ◽  
Andrea Vania ◽  
Phuoc Vinh Dang
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Journal Bearings ◽  
Maximum Temperature ◽  
Inlet Temperature ◽  
Oil Film ◽  
External Cooling ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearings

Tilting-pad journal bearings (TPJBs) are widely installed in rotating machines owing to their high stability, but some drawbacks can be noted, such as higher cost with respect to cylindrical journal bearings and thermal issues. High temperatures in the pads correspond to low oil-film thicknesses and large thermal deformations in the pads. Therefore, the restriction of the maximum temperature of the bearing is a key aspect for oil-film bearings. The temperature reduction is generally obtained by adopting higher oil inlet flowrates or suitable oil nozzles. In this paper, the idea of using cooled pads with internal channels in which an external cooling fluid is circulated will be applied to a TPJB for the first time. The three-dimensional TEHD model of the TPJB, equipped with a cooled pad, will be introduced, and the results of the numerical simulations will be discussed. Several analyses have been performed in order to investigate the influence of cooling conditions, such as the type, flowrate, inlet temperature and number of cooled pads. Two types of pad geometry with different cross-sections of the cooling circuit, namely, circular and six-square multi-channel sections, have been compared to the reference bearing with solid pads. Simple experimental tests were performed by means of a test rig equipped with a cooled pad bearing obtained with the additive manufacturing process, thus showing the effectiveness of the solution and the agreement with the predictions.

Darryl E. Metzger Memorial Session Paper: Comparison of Calculated and Measured Heat Transfer Coefficients for Transonic and Supersonic Boundary-Layer Flows

1995 ◽  
Vol 117 (2) ◽  
pp. 248-254 ◽  
Author(s):  
C. Hu¨rst ◽  
A. Schulz ◽  
S. Wittig
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Reynolds Number ◽  
High Speed ◽  
Three Dimensional ◽  
Supersonic Boundary Layer ◽  
Nozzle Wall ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Three Dimensional Finite Element

The present study compares measured and computed heat transfer coefficients for high-speed boundary layer nozzle flows under engine Reynolds number conditions (U∞=230 ÷ 880 m/s, Re* = 0.37 ÷ 1.07 × 106). Experimental data have been obtained by heat transfer measurements in a two-dimensional, nonsymmetric, convergent–divergent nozzle. The nozzle wall is convectively cooled using water passages. The coolant heat transfer data and nozzle surface temperatures are used as boundary conditions for a three-dimensional finite-element code, which is employed to calculate the temperature distribution inside the nozzle wall. Heat transfer coefficients along the hot gas nozzle wall are derived from the temperature gradients normal to the surface. The results are compared with numerical heat transfer predictions using the low-Reynolds-number k–ε turbulence model by Lam and Bremhorst. Influence of compressibility in the transport equations for the turbulence properties is taken into account by using the local averaged density. The results confirm that this simplification leads to good results for transonic and low supersonic flows.

Notch Arrangement Effects on Heat Transfer in a Channel With Cut-Fins

2007 ◽  
Author(s):  
Kazuya Tatsumi ◽  
Shintaro Matsuzaki ◽  
Kazuyoshi Nakabe
Keyword(s):  
Heat Transfer ◽  
Pressure Loss ◽  
Three Dimensional ◽  
Main Flow ◽  
Loss Reduction ◽  
Transfer Coefficients ◽  
Piv Measurements ◽  
Heat Transfer Coefficients ◽  
Overall Performance ◽  
Spanwise Flow

The effects of the attack-angle of the fin notch array against the main flow and size of the clearance at the fin-tip on the heat transfer and pressure loss performances of a channel with cut-fins (parallel fins with square notches) mounted on the bottom wall were evaluated in the present article. Three-dimensional numerical simulations, PIV measurements and heat transfer experiments employing a modified single-blow method were conducted to discuss these characteristics. Larger pressure loss reduction was obtained by the cut-fins case compared with the plain-fins case (parallel fins without notches) under smaller clearance conditions, while smaller thermal resistance was achieved with larger clearance. A maximum peak, therefore, appeared in the overall performance in relation with the clearance size. Larger heat transfer coefficients were obtained with smaller attack-angles of the notch array in both experimental and numerical results, particularly under larger Reynolds number conditions. This was due to the spanwise flow generated in the area adjacent to the notch, by which renewal of the thermal boundary layer was effectively produced at the trailing edge of the notch.

Design of an axially concave pad profile for a large turbine tilting-pad bearing

2016 ◽  
Vol 231 (4) ◽  
pp. 479-488 ◽  
Author(s):  
Sebastian Kukla ◽  
Nico Buchhorn ◽  
Beate Bender
Keyword(s):  
Heat Transfer ◽  
Film Thickness ◽  
Load Capacity ◽  
Measurement Data ◽  
Tangential Direction ◽  
Measured Temperature ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Tilting Pad ◽  
Calculation Results

To improve operational safety and/or achieve a higher load capacity of turbine tilting-pad bearings, an axially concave pad profile is presented. The thermal and mechanical stress of the loaded pads of a test bearing in load between pivot configuration has been analysed. Both film thickness and pressure distribution have been measured at a very high resolution. A fluid film calculation program in combination with a finite-volume-based structural mechanics program is used to simulate the deformation of a single pad under high circumferential speeds. In this context, the axial and tangential heat transfer coefficients of the pad surface, which act as boundary conditions for the calculation of the 3D temperature distribution, are determined using an optimization process. Herein, the match of predicted and measured pad temperatures is the goal. It can be shown that there must be a huge difference in heat transfer in axial and tangential direction in order to match the large measured temperature gradient in circumferential direction. Based on the measured deformed profile the program code is used to derive a concave pad profile, which will result in an axially non-arched sliding surface under the expected thermal load. Therefore, an iterative simulation procedure is used. By decreasing the axial arching of the pad and thus the large film thickness at the axial ends using an improved profile designed for a specific operation point, the minimum film thickness and maximum pad temperature can be influenced beneficially. The comparison of measurement data and calculation results shows very good agreement regarding the pad deformations. The results indicate that by axially concave profiling of the loaded pads of a large tilting-pad bearing for a specific operation point, the static characteristics in the form of temperature, film thickness and load capacity can be improved.

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