Transient Thermoelastohydrodynamic Study of Tilting-Pad Journal Bearings—Comparison Between Experimental Data and Theoretical Results

1997 ◽  
Vol 119 (3) ◽  
pp. 401-407 ◽  
Author(s):  
P. Monmousseau ◽  
M. Fillon ◽  
J. Freˆne
Keyword(s):  
Experimental Data ◽  
Journal Bearing ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Experimental Investigations ◽  
Time Step ◽  
Start Up ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing ◽  
Theoretical Results

The aim of this paper is to study the increase in temperature of an unloaded tilting-pad journal bearing during rapid start-up. First, an analysis is carried out to choose an appropriate time step and grid refinement to minimize numerical errors. Then, the transient THD and TEHD theoretical models are developed to show the influence of solid bearing deformations. Experimental tests are realized on a four-shoe tilting-pad journal bearing. The temperatures at the shaft and pad surfaces, at the half thickness and the back of the pads are compared for both theoretical and experimental investigations. Good agreement is found between the theoretical results and the experimental data, especially when the variation of the operating bearing clearance is taken into account.

Three-Dimensional Dynamic Model of TEHD Tilting-Pad Journal Bearing—Part II: Parametric Studies

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Junho Suh ◽  
Alan Palazzolo
Keyword(s):  
Dynamic Analysis ◽  
Numerical Integration ◽  
Equilibrium Condition ◽  
Journal Bearing ◽  
Fe Model ◽  
Time Step ◽  
Transient Dynamic ◽  
Tilting Pad ◽  
Nonlinear Transient ◽  
Tilting Pad Journal Bearing

This paper presents a new analysis method for a thermo-elasto-hydro-dynamic (TEHD) tilting pad journal bearing (TPJB) system to reach a static equilibrium condition adopting nonlinear transient dynamic solver, whereas earlier studies have used iteration schemes such as Newton–Raphson method. The theoretical TPJB model discussed in Part I of this research is combined into a newly developed algorithm to perform a bearing dynamic analysis and present dynamic coefficients. In the nonlinear transient dynamic solver, physical and modal coordinates coexist for computational efficiency, and transformation between modal and physical coordinate is performed at each numerical integration time step. Variable time step Runge–Kutta numerical integration scheme is adopted for a reliable and fast calculation. Nonlinear time transient dynamic analysis and steady thermal analysis are combined to find the static equilibrium condition of the TPJB system, where the singular matrix issue of flexible pad finite element (FE) model is resolved. The flexible pad TPJB model was verified by comparison with other numerical results. Simulation results corresponding with the theoretical model explained in Part I are presented and discussed. It explains how the TPJB dynamic behavior is influenced by a number of eigenvector of flexible pad FE model and pad thickness. Preload change under fluid and thermal load is examined.

scholarly journals Static Characteristics of a Tilting Five-Pad Journal Bearing with an Asymmetric Geometry

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 89
Author(s):  
Phuoc Vinh Dang ◽  
Steven Chatterton ◽  
Paolo Pennacchi
Keyword(s):  
Static Load ◽  
Journal Bearing ◽  
Experimental Tests ◽  
Experimental Measurements ◽  
Static Characteristics ◽  
Distribution Profile ◽  
Tilting Pad ◽  
Static Eccentricity ◽  
Temperature And Pressure ◽  
Tilting Pad Journal Bearing

In this paper, static characteristics of a tilting five-pad rocker-backed journal bearing with an asymmetric geometry, i.e., different clearance for each pad, are investigated. A thermo-elasto-hydrodynamic (TEHD) model considering the elasticity of the pad and pivot is used for the simulation. The pivot stiffness of each pad obtained by experiment is also introduced in the model. The experimental tests were carried out on a tilting pad journal bearing (TPJB) with a nominal diameter of 100 mm and a length-to-diameter (L/D) ratio of 0.7 with load-between-pad (LBP) and load-on-pad (LOP) arrangements. Several analyses, including numerical simulations and experimental measurements, are implemented in order to obtain the static behaviors of the tilting-pad bearing under variations of rotational speed, amplitude and direction of applied static load, such as clearance distribution profile, static eccentricity, temperature and pressure distribution. The results show that the effect of asymmetric geometry on the static characteristics is not negligible.

Transient Thermoelastohydrodynamic Study of Tilting-Pad Journal Bearings—Application to Bearing Seizure

1998 ◽  
Vol 120 (2) ◽  
pp. 319-324 ◽  
Author(s):  
P. Monmousseau ◽  
M. Fillon ◽  
J. Freˆne
Keyword(s):  
Hydrodynamic Limit ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Safe Operation ◽  
Thermal Limit ◽  
Start Up ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings

Nowadays, tilting-pad journal bearings are used under more and more severely demanding operating conditions. Three limits of safe operation were defined (Leopard, 1976): the hydrodynamic limit, the mechanical limit and the thermal limit. The purpose of this study is to determine the hydrodynamic limit of safe operation during start-up for a tilting-pad journal bearing. During start-up, the rapid increase of the temperature in the bearing solids leads to the thermal expansion of both the pads and the shaft. The operating bearing clearance decreases and, when it tends toward zero, seizure occurs. The evolution of the main characteristics (temperature, pressure, film thickness and displacements) versus time is analyzed in the case when a seizure occurs.

A Global Approach of Thermal Effects Including Pad Deformations in Tilting-Pad Journal Bearings Submitted to Unbalance Load

1996 ◽  
Vol 118 (1) ◽  
pp. 169-174 ◽  
Author(s):  
M. Fillon ◽  
H. Desbordes ◽  
J. Freˆne ◽  
C. Chan Hew Wai
Keyword(s):  
Thermal Effects ◽  
Journal Bearing ◽  
Great Influence ◽  
Maximum Pressure ◽  
Time Interval ◽  
Tilting Pad ◽  
Minimum Film Thickness ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings ◽  
Theoretical Results

The purpose of this paper is to study the response of a tilting-pad journal bearing submitted to an unbalance load. A pseudo-time transient analysis has been developed taking into account the effective viscosity of the lubricant, the thermal expansion of bearing elements, and the elastic pad deformations. At each time interval, and for each pad, an effective temperature of the film is deduced from an energy balance. First, a comparison between theoretical results and experimental data is presented for a four-shoe tilting-pad journal bearing subjected to a static load. Second, the influence of the thermal and pad flexibility effects on the journal center orbit, on the minimum film thickness and on the maximum pressure is studied for various unbalance loads. Both the viscosity variation and the operating clearances due to elastic and thermal deformations of the bearing elements have a great influence on the behavior of the bearing.

A Tilting Pad Journal Bearing Model for Coupled Fluid Dynamical-Rotor Dynamical Analyses

2015 ◽  
Author(s):  
R. Conti ◽  
A. Frilli ◽  
E. Galardi ◽  
E. Meli ◽  
D. Nocciolini ◽  
...  
Keyword(s):  
Journal Bearing ◽  
Experimental Tests ◽  
Journal Bearings ◽  
Coupled Analysis ◽  
Accurate Analysis ◽  
Technical Data ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings ◽  
Modelling Approach

Turbomachines are continuously developing in order to reach higher levels of speed, power and efficiency and the classical Fixed Geometry Journal Bearings have been replaced by Tilting Pad Journal Bearings to avoid instability phenomena. In this paper, the authors propose an innovative quasi-3D TPJB modelling approach that allows the simultaneous and coupled analysis of the typical phenomena involved in TPJB operations. The authors focused on the accurate analysis of the interactions between the rotor and the lubricant supply plant and on the fluid dynamical effects due to the bearing that cause those couplings, aiming at reaching a good compromise between the accuracy and the numerical efficiency of the model (mandatory to analyze systems with many bearings). The TPJB model has been developed and experimentally validated in collaboration with Nuovo Pignone General Electric S.p.a. which provided the technical data of the system and the results of experimental tests.

scholarly journals Evaluation of the Thermal Effects in Tilting Pad Bearing

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
G. B. Daniel ◽  
K. L. Cavalca
Keyword(s):  
Temperature Distribution ◽  
Pressure Distribution ◽  
Thermal Effects ◽  
Journal Bearing ◽  
Experimental Tests ◽  
Maximum Temperature ◽  
Oil Film ◽  
Operational Conditions ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing

The analysis of thermal effects is of expressive importance in the context of rotordynamics to evaluate the behavior of hydrodynamic bearings because these effects can influence their dynamic characteristics under specific operational conditions. For this reason, a thermohydrodynamic model is developed in this work, in which the pressure distribution in the oil film and the temperature distribution are calculated together. From the pressure distribution, the velocity distribution field is determined, as well as the viscous dissipation, and consequently, the temperature distribution. The finite volume method is applied to solve the Reynolds equation and the energy equation in the thermohydrodynamic model (THD). The results show that the temperature is higher as the rotational speed increases due to the shear rate of the oil film. The maximum temperature in the bearing occurs in the overloaded pad, near the outlet boundary. The experimental tests were performed in a tilting pad journal bearing operating in a steam turbine to validate the model. The comparison between the experimental and numerical results provides a good correlation. The thermohydrodynamic lubrication developed in this assignment is promising to consistently evaluate the behavior of the tilting pad journal bearing operating in relatively high rotational speeds.

scholarly journals Improvement of Tilting-Pad Journal Bearing Operating Characteristics by Application of Eddy Grooves

Lubricants ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 18
Author(s):  
Eckhard Schüler ◽  
Olaf Berner
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Fluid Film ◽  
Operating Characteristics ◽  
Fluid Film Bearings ◽  
Tilting Pad ◽  
Bearing Load ◽  
Bearing Loads ◽  
Tilting Pad Journal Bearing

In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

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.

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