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 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.

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.

Numerical Investigation for Characteristics and Oil-Air Distributions of Oil Film in a Tilting-Pad Journal Bearing

2018 ◽  
Author(s):  
Aoshuang Ding ◽  
Yaobing Xiao
Keyword(s):  
Shear Stress ◽  
Journal Bearing ◽  
Volume Fraction ◽  
Side Wall ◽  
Mechanical Loss ◽  
Load Pressure ◽  
Oil Film ◽  
Air Volume ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing

This paper analyzes the effects of air in the oil film of a tilting-pad journal bearing on oil-air distributions and characteristics. With a gaseous cavitation model and shear stress transport (SST) model with low-Re correction included, the air backflow from the outlet boundary is analyzed in numerical simulations of a titling-pad journal bearing at 3000 rpm rotation speed and under 180 kN load. The simulated bearing load, pressure and mechanical loss are in good accordance with the experimental data, indicating that the simulation results of the air backflow from the outlet boundary can catch the hydrodynamic characteristics accurately. Based on the analyses of simulated air volume fraction and shear stress, the shear stress of the high-pressure loaded area is mainly influenced by the velocity gradient in the normal direction to the rotor-side wall, not the air backflow and gaseous cavitation. In the unloaded area, the gaseous cavitation occurs around the center part, following the gaseous cavitation mechanisms. The backflow air flows into the low-pressure unloaded area from the outlet boundary and has a clear interval with the air from the gaseous cavitation. The air volume fraction increases with these two air sources and affects the mixture viscosity significantly, eventually influencing the shear stress on the rotor-side wall and bearing mechanical loss.

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.

scholarly journals Analysis of the multiphase lubricating oil effect on the performance of the tilting-pad journal bearing

2021 ◽  
pp. 92-92
Author(s):  
Yuchuan Zhu ◽  
Zhengyi Jiang ◽  
Ling Yan ◽  
Yan Li ◽  
Fangfang Ai ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
High Speed ◽  
Journal Bearing ◽  
Lubricating Oil ◽  
Loading Capacity ◽  
Heavy Load ◽  
Oil Film ◽  
Tilting Pad ◽  
Multiphase Fluid ◽  
Tilting Pad Journal Bearing

The multiphase fluid dynamics is used to model the oil film in the tilting-pad journal bearing. Particles are added to the lubricating oil and the change of loading capacity of oil film is studied numerically. The performance of the bearing under high-speed and heavy load are elucidated. The results show that the bearing capacity depends upon concentration, diameter and density of particles.

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.

Numerical investigation for characteristics and oil–air distributions of oil film in a tilting-pad journal bearing

2019 ◽  
Vol 234 (2) ◽  
pp. 193-204
Author(s):  
Aoshuang Ding ◽  
Xiaodong Ren ◽  
Xuesong Li ◽  
Chunwei Gu
Keyword(s):  
Shear Stress ◽  
Journal Bearing ◽  
Volume Fraction ◽  
Mechanical Loss ◽  
Load Pressure ◽  
High Rotational Speed ◽  
Oil Film ◽  
Air Volume ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing

This paper analyzes the effects of air in the oil film of a tilting-pad journal bearing on oil–air distributions and characteristics. With a gaseous cavitation model and shear stress transport model with low-Re correction included, the air backflow from the outlet boundary is analyzed in numerical simulations of a titling-pad journal bearing at 3000 r/min rotation speed and under 180 kN load. The simulated bearing load, pressure, and mechanical loss are in good accordance with the experimental data, indicating that the simulation results of the air backflow from the outlet boundary can catch the hydrodynamic characteristics accurately. Based on the turbulence viscosity ratio analysis, the turbulence effect cannot be ignored at the high rotational speed. With the comparison between the unloaded area and the loaded area, the boundary layer and turbulent flow develops with the film thickness increasing. Based on the analyses of simulated air volume fraction and pressure distribution, the gaseous cavitation occurs around the center part of the unloaded area, following the gaseous cavitation mechanisms. The backflow air flows into the low-pressure unloaded area from the outlet boundary and has a clear interval with the air from the gaseous cavitation. The air volume fraction increases with these two air sources and affects the mixture viscosity significantly, eventually influencing the shear stress on the rotor-side wall and bearing mechanical loss.

On the Simplifications for the Thermal Modeling of Tilting-Pad Journal Bearings Under Thermoelastohydrodynamic Regime

2012 ◽  
Author(s):  
Alejandro Cerda Varela ◽  
Michel Fillon ◽  
Ilmar Ferreira Santos
Keyword(s):  
Heat Transfer ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Laminar Regime ◽  
Transfer Effects ◽  
Oil Film ◽  
Tilting Pad ◽  
Heat Transfer Effects ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings

The relevance of calculating accurately the oil film temperature build up when modeling tilting-pad journal bearings is well established within the literature on the subject. This work studies the feasibility of using a thermal model for the tilting-pad journal bearing which includes a simplified formulation for inclusion of the heat transfer effects between oil film and pad surface. Such simplified approach becomes necessary when modeling the behavior of tilting-pad journal bearings operating on controllable lubrication regime. Three different simplified heat transfer models are tested, by comparing their results against the ones obtained from an state of the art tilting-pad journal bearing model, where the heat transfer effects are throughly implemented, as well as against some experimental results from the literature. The results obtained show that the validity of the simplified heat transfer models are strongly dependent on the Reynolds number for the oil flow in the bearing. For bearings operating in laminar regime, the decoupling of the oil film energy equation solving procedure, with no heat transfer terms included, with the pad heat conduction problem, where the oil film temperature is applied at the boundary as a Dirichlet condition, showed a good balance between quality of the results, implementation easiness and reduction in calculation time. For bearings on the upper limit of the laminar regime, the calculation of an approximated oil film temperature gradient in the radial direction, as proposed by Knight and Barrett, delivered the best results.

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