The Effects of Three-Dimensional Pad Deformations on Tilting-Pad Journal Bearings Under Dynamic Loading

1995 ◽  
Vol 117 (3) ◽  
pp. 379-384 ◽  
Author(s):  
H. Desbordes ◽  
M. Fillon ◽  
J. Freˆne ◽  
C. Chan Hew Wai
Keyword(s):  
Film Thickness ◽  
Three Dimensional ◽  
Journal Bearings ◽  
Maximum Pressure ◽  
Tilting Pad ◽  
Axial Profile ◽  
The One ◽  
D Model ◽  
Bearing Behavior ◽  
Tilting Pad Journal Bearings

Pad distortions are generally not taken into account for the dynamic study of tilting-pad journal bearings. The objective of this paper is both to show the influence of the three-dimensional (3-D) pad deformations due to the pressure field on the bearing response and to analyse the bearing behavior for various unbalance eccentricities. Similar orbits are obtained using 2-D or 3-D pad deformations; however, due to the axial profile of the film thickness, the minimum film thickness obtained with the 3-D model is about 40 percent lower than the one obtained with the 2-D model for the greatest unbalance eccentricity. The maximum pressure is decreased by about 16 percent when the 3-D model is used but that value is nearly similar to the one obtained without deformation. The dynamic behavior of the bearing is largely modified when the dynamic load is greater than the static load.

Dynamic Analysis of Tilting-Pad Journal Bearing—Influence of Pad Deformations

1994 ◽  
Vol 116 (3) ◽  
pp. 621-627 ◽  
Author(s):  
H. Desbordes ◽  
M. Fillon ◽  
C. Chan Hew Wai ◽  
J. Frene
Keyword(s):  
Film Thickness ◽  
Pressure Field ◽  
Journal Bearing ◽  
Maximum Pressure ◽  
Tilting Pad ◽  
Minimum Film Thickness ◽  
Dimensional Finite Element ◽  
The One ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings

A theoretical nonlinear analysis of tilting-pad journal bearings is presented for small and large unbalance loads under isothermal conditions. The radial displacements of internal pad surface due to pressure field are determined by a two-dimensional finite element method in order to define the actual film thickness. The influence of pad deformations on the journal orbit, on the minimum film thickness and on the maximum pressure is studied. The effects of pad displacements are to decrease the minimum film thickness and to increase the maximum pressure. The orbit amplitude is also increased by 20 percent for the large unbalance load compared to the one obtained for rigid pad.

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.

Dynamic Properties of Tilting-Pad Journal Bearings: Experimental and Theoretical Investigation of Frequency Effects due to Pivot Flexibility

2006 ◽  
Vol 129 (3) ◽  
pp. 865-869 ◽  
Author(s):  
Waldemar Dmochowski
Keyword(s):  
High Speed ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Damping Properties ◽  
Frequency Effects ◽  
Tilting Pad ◽  
Stiffness And Damping ◽  
Tilting Pad Journal Bearings

Tilting-pad journal bearings (TPJBs) dominate as rotor supports in high-speed rotating machinery. The paper analyzes frequency effects on the TPJB’s stiffness and damping characteristics based on experimental and theoretical investigations. The experimental investigation has been carried out on a five pad tilting-pad journal bearing of 98mm in diameter. Time domain and multifrequency excitation has been used to evaluate the dynamic coefficients. The calculated results have been obtained from a three-dimensional computer model of TPJB, which accounts for thermal effects, turbulent oil flow, and elastic effects, including that of pad flexibility. The analyzes of the TPJB’s stiffness and damping properties showed that the frequency effects on the bearing dynamic properties depend on the operating conditions and bearing design. It has been concluded that the pad inertia and pivot flexibility are behind the variations of the stiffness and damping properties with frequency of excitation.

Dynamic Properties of Tilting-Pad Journal Bearings: Experimental and Theoretical Investigation of Frequency Effects Due to Pivot Flexibility

2006 ◽  
Author(s):  
Waldemar Dmochowski
Keyword(s):  
High Speed ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Damping Properties ◽  
Frequency Effects ◽  
Tilting Pad ◽  
Stiffness And Damping ◽  
Tilting Pad Journal Bearings

Tilting-pad journal bearings (TPJB) dominate as rotor supports in high speed rotating machinery. The paper analyzes frequency effects on the TPJB’s stiffness and damping characteristics based on experimental and theoretical investigations. The experimental investigation has been carried out on a five pad tilting-pad journal bearing of 98 mm in diameter. Time domain and multifrequency excitation has been used to evaluate the dynamic coefficients. The calculated results have been obtained from a three-dimensional computer model of TPJB, which accounts for thermal effects, turbulent oil flow, and elastic effects, including that of pad flexibility. The analyzes of the TPJB’s stiffness and damping properties showed that the frequency effects on the bearing dynamic properties depend on the operating conditions and bearing design. It has been concluded that the pad inertia and pivot flexibility are behind the variations of the stiffness and damping properties with frequency of excitation.

Efficient Models of Three-Dimensional Tilting Pad Journal Bearings for the Study of the Interactions Between Rotor and Lubricant Supply Plant

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Rindi ◽  
Stefano Rossin ◽  
R. Conti ◽  
A. Frilli ◽  
E. Galardi ◽  
...  
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
3D Models ◽  
Industrial Applications ◽  
Journal Bearings ◽  
Research Activity ◽  
Steady State Condition ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearings

In many industrial applications, tilting pad journal bearings (TPJBs) are increasingly used because they are very suitable both for high-speed and high external loads. Their study is fundamental in rotating machines and a compromise between accuracy and numerical efficiency is mandatory to achieve reliable results in a reasonable time. This paper mainly focuses on the development of efficient three-dimensional (3D) models of TPJBs, in order to contemporaneously describe both the rotor dynamics of the system and the lubricant supply plant in long simulations (from the initial transient phase to the steady-state condition). Usually, these two aspects are studied separately, but their interactions must be considered if an accurate description of the whole system is needed. The proposed model architecture considers all the six degrees-of-freedom (DOFs) between supporting structures and rotors and can be applied to different types of TJPB layout with different lubricant supply plants. In this research activity, the whole model has been developed and validated in collaboration with Nuovo Pignone General Electric S.p.a. which provided the required technical and experimental data.

Characterization of Five-Pad Tilting-Pad Journal Bearings Using an Original Test-Rig

2011 ◽  
Author(s):  
S. Chatterton ◽  
P. Pennacchi ◽  
A. Vania ◽  
E. Tanzi ◽  
R. Ricci
Keyword(s):  
Film Thickness ◽  
Gas Turbines ◽  
Journal Bearings ◽  
Fluid Film ◽  
Test Rig ◽  
Theoretical Evaluation ◽  
Oil Film ◽  
Tilting Pad ◽  
Fluid Film Thickness ◽  
Tilting Pad Journal Bearings

Tilting-pad journal bearings are installed with increased frequency owing to their dynamic stability characteristics in several rotating machine applications, typically in high rotating speed cases. This usually happens for new installations in highspeed compressors or during revamping operations of steam and gas turbines for power generation. The selection from a catalogue, or the design of a new bearing, requires the knowledge of the bearing characteristics such as babbitt metal temperatures, fluid-film thickness, load capacity, stiffness and damping coefficients. Temperature and fluid-film thickness are essential for the safety of the bearing. Babbitt metal is subject to creep at high temperatures, as it happens at high speed operations. On the contrary, at low speed or with high loads, oil-film thickness could be too low, resulting in metal to metal contact. Oil-film dynamic coefficients are largely responsible of the dynamic behaviour and of the stability of the rotor-tilting-pad-bearing system. Therefore, the theoretical evaluation and/or the experimental estimation of these coefficients are mandatory in the design phase. The theoretical evaluation of these coefficients for tilting pad journal bearings is difficult due to their complex geometry, boundary and thermal conditions and turbulent flow, whereas an experimental characterization requires a suitable test rig. The paper describes the test rig designed to this purpose and its unusual configuration with respect to other test rigs available in literature. Some preliminary tests performed for the bearing characterization are also shown.

Experimental study on pad temperature and film thickness of tilting-pad journal bearings with an elastic-pivot pad

2015 ◽  
Vol 88 ◽  
pp. 228-235 ◽  
Author(s):  
Fan Zhang ◽  
Wu Ouyang ◽  
Honglun Hong ◽  
Yongsheng Guan ◽  
Xiaoyang Yuan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Film Thickness ◽  
Journal Bearings ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearings
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