Thermohydrodynamic Analysis of Tilting-Pad Journal Bearings Operating in Turbulent Flow Regime

1996 ◽  
Vol 118 (1) ◽  
pp. 225-231 ◽  
Author(s):  
L. Bouard ◽  
M. Fillon ◽  
J. Freˆne
Keyword(s):  
Turbulent Flow ◽  
Flow Regime ◽  
Local Heat ◽  
Journal Bearings ◽  
Local Analysis ◽  
Maximum Temperature ◽  
Turbulent Flow Regime ◽  
Tilting Pad ◽  
Local Heat Flux ◽  
Tilting Pad Journal Bearings

A thermohydrodynamic analysis of tilting-pad bearing in turbulent flow regime is presented. Two tilting-pad journal bearings are studied. A local analysis of thermal turbulent phenomena is shown. The theoretical prediction of the maximum temperature decreases when the flow regime becomes nonlaminar and the decrease corresponding to higher power losses is explained using the velocity component profiles and the local heat flux in the film.

Transient Thermoelastohydrodynamic Study of Tilting-Pad Journal Bearings Under Dynamic Loading

1998 ◽  
Vol 120 (2) ◽  
pp. 405-409 ◽  
Author(s):  
P. Monmousseau ◽  
M. Fillon ◽  
J. Freˆne
Keyword(s):  
Steady State ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Tilting Pad ◽  
Transient Period ◽  
Final Steady State ◽  
Tilting Pad Journal Bearings

Nowadays, tilting-pad journal bearings are submitted to more and more severe operating conditions. The aim of this work is to study the thermal and mechanical behavior of the bearing during the transient period from an initial steady state to a final steady state (periodic). In order to study the behavior of this kind of bearing under dynamic loading (Fdyn) due to a blade loss, a nonlinear analysis, including local thermal effects, realistic boundary conditions, and bearing solid deformations (TEHD analysis) is realized. After a comparison between theoretical results obtained with four models (ISO, ADI, THD, and TEHD) and experimental data under steady-state operating conditions (static load Ws), the evolution of the main characteristics for three different cases of the dynamic load (Fdyn/Ws < 1, Fdyn/Ws = 1 and Fdyn//Ws > 1) is discussed. The influence of the transient period on the minimum film thickness, the maximum pressure, the maximum temperature, and the shaft orbit is presented. The final steady state is obtained a long time after the appearance of a dynamic load.

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.

scholarly journals Performance of Tilting Pad Journal Bearings with the Same Sommerfeld Number

2020 ◽  
Vol 10 (10) ◽  
pp. 3529
Author(s):  
Sung-Hwa Jeung ◽  
Junho Suh ◽  
Hyun Sik Yoon
Keyword(s):  
Thermal Behavior ◽  
Elastic Deformation ◽  
Heat Generation ◽  
Thermal Deformation ◽  
Journal Bearings ◽  
Hertzian Contact ◽  
Maximum Temperature ◽  
Oil Film ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearings

This paper presents the change of non-dimensional characteristics and thermal behavior of different sized tilting pad journal bearings (TPJBs) with the same Sommerfeld number. A three-dimensional (3D) TPJB numerical model is provided considering the thermo-elastic hydro-dynamic (TEHD) lubrication model with pad thermal-elastic deformation. The pivot stiffness is assumed to be the combination of linear and cubic stiffness based on the Hertzian contact theory. The TPJBs in a configuration of load between pad (LBP) with the same Sommerfeld number having seven different sizes are simulated, and their non-dimensional dynamic and static characteristics and thermal behavior are compared. Pad thermal and elastic deformation are both taken into account. If the changes in lubricant viscosity, thermal deformation, and elastic deformation of journal/pads due to viscous shearing are ignored, the bearings with identical Sommerfeld numbers should show the same performance characteristics. However, the heat generation at the bearing clearance during operation (a) induces a decrease in viscosity and heat transfer to journal/pads and (b) results in a thermal deformation. Furthermore, the elastic deformation of the tilting pads and pivots also affects the bearing dynamic performance. For the same Sommerfeld number, the numerical analyses provide how the viscous shearing and elastic deformation lead to a change in bearing performance. For the small bearings with the same Sommerfeld number, the non-dimensional characteristics did not change significantly, where the heat generation was small being compared to the large sized bearing. The largest change in non-dimensional characteristics occurred when the maximum temperature of the oil film increased by 30 °C or more compared to the lubricant supply temperature. The root cause of the change in the non-dimensional characteristics is the viscous shearing in the oil film, and the thermal deformation of the structures surrounding the oil film acts in combination. These results provide insight into the Sommerfeld number, which can be used for the early stage of bearing design.

Thermohydrodynamic Design Charts for Tilting-Pad Journal Bearings

1996 ◽  
Vol 118 (1) ◽  
pp. 232-238 ◽  
Author(s):  
M. Fillon ◽  
M. Khonsari
Keyword(s):  
Boundary Conditions ◽  
Temperature Rise ◽  
Effective Temperature ◽  
Journal Bearings ◽  
Maximum Temperature ◽  
Experimental Measurements ◽  
Design Chart ◽  
Design Charts ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearings

Design charts are presented which allow one to predict the maximum temperature and a realistic effective temperature of five-shoe tilting-pad bearings. The charts utilize two dimensionless parameters which characterize the temperature rise in the film based on the ISOADI boundary conditions. A number of examples are presented to illustrate the utility of the design chart where the results are compared to both experimental measurements and full THD simulations.

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