Oil film inlet temperature model for directed lubrication tilting pad journal bearing

A comparative study between a conventional- and leading edge grooved (LEG) tilting pad journal bearing (TPJB) segment is performed. The developed model uses the Shear Stress Transport (SST) turbulence model, coupled with the energy equation and a partial differential equation for the fluid domain mesh displacement to predict the thermal flow characteristics. Instead of using an effective boundary condition to determine the inlet temperature of the LEG pad and excluding the additional LEG portion, as is common practice, the whole geometry of the LEG is modeled. Several sizes of the LEG portion is investigated and it is shown to have quite a small influence on pressure, temperature, film thickness and turbulence intensity. Moreover, the results also show that the conventional pad gives rise to higher levels of turbulence in the mid plane compared to its LEG counterpart, while the latter has a marginally higher value of turbulence when the volume average value is computed. The maximum value of turbulence is however present in the conventional model.

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

Volume 7B: Structures and Dynamics ◽

10.1115/gt2018-75888 ◽

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.

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

Thermal Science ◽

10.2298/tsci191112092z ◽

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.

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

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650119858241 ◽

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.

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

Volume 7: Structures and Dynamics, Parts A and B ◽

10.1115/gt2012-68329 ◽

2012 ◽

Cited By ~ 5

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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Cooling Effect and Dynamic Characteristics of Oil Film of Partial Tilting Pad Bearing

ASME/STLE 2007 International Joint Tribology Conference, Parts A and B ◽

10.1115/ijtc2007-44023 ◽

2007 ◽

Cited By ~ 1

Author(s):

Kyung-Bo Bang ◽

Jeong-Hun Kim ◽

Cheol-Hong Kim

Keyword(s):

Dynamic Characteristics ◽

Journal Bearing ◽

Hydrodynamic Pressure ◽

Oil Film ◽

Rotating Speed ◽

Damping Coefficients ◽

Tilting Pad ◽

Oil Flow ◽

Stiffness And Damping ◽

Tilting Pad Journal Bearing

In the present paper, we suggest a new type of tilting pad journal bearing to decrease oil film temperature and eliminate pad fluttering during operation. This bearing consists of tilting pad journal bearing at low casing and fixed arc type journal bearing at upper casing. Namely we changed a tilting pad bearing with a fixed arc type bearing at upper casing. To investigate the effects of changing the bearing shape, the static and dynamic characteristics were compared experimentally with conventional tilting pad journal bearing. For the static characteristics, oil film temperature, hydrodynamic pressure and oil film thickness were measured with the variation of rotating speed, bearing load and oil flow rate. The stiffness and damping coefficients of oil film were also obtained using the response subjected to harmonic external force to evaluating the dynamic characteristics. The results show that the suggested type of bearing has effect on reducing oil film temperature and increasing stiffness and damping coefficients of oil film.

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A Thermohydrodynamic Analysis of Large Tilting-Pad Journal Bearing in Laminar and Turbulent Flow Regimes With Mixing

Journal of Tribology ◽

10.1115/1.2920291 ◽

1990 ◽

Vol 112 (3) ◽

pp. 542-548 ◽

Cited By ~ 54

Author(s):

S. Taniguchi ◽

T. Makino ◽

K. Takeshita ◽

T. Ichimura

Keyword(s):

Turbulent Flow ◽

Flow Model ◽

Journal Bearing ◽

Three Dimensional ◽

Flow Regimes ◽

Inlet Temperature ◽

Tilting Pad ◽

Laminar And Turbulent Flow ◽

Tilting Pad Journal Bearing ◽

Good Agreement

This paper describes a thermohydrodynamic analysis of the 19 in. diameter tilting-pad journal bearing for steam turbine in comparison with experimental data. The three-dimensional thermohydrodynamic analysis is performed in both laminar and turbulent flow regimes considering mixing inlet temperature. The linearized turbulent flow model derived by Ng and Pan (1965) is applied. Generally good agreement is obtained for bearing surface temperatures, frictional losses, and minimum film thicknesses between the theoretical and experimental results.

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The Influence of Pad Pivot Elastic Deformation on Static and Dynamic Coefficients for Fixed-Tilting Pad Journal Bearing

Volume 9: Mechanics of Solids, Structures and Fluids; NDE, Structural Health Monitoring and Prognosis ◽

10.1115/imece2017-70464 ◽

2017 ◽

Author(s):

Tian Jiale ◽

Yang Baisong ◽

Sun Yanhua ◽

Yu Lie ◽

Zhou Jian

Keyword(s):

Elastic Deformation ◽

High Speed ◽

Journal Bearing ◽

Dynamic Stiffness ◽

Dynamic Performance ◽

Oil Film ◽

Dynamic Coefficients ◽

Tilting Pad ◽

Two Factors ◽

Tilting Pad Journal Bearing

High-speed and heavy-loaded rotating machinery require accurate prediction of rotor’s response and stability, which can be characterized by the static and dynamic coefficients of the bearing support. In this paper, a theoretical study has been done to investigate the performance of a fixed-tilting pad journal bearing with ball-in-socket pivot. The analytical model is established with the flexibility of the pad pivot and turbulent effect of the oil film both taken consideration. Under such situation, the pad pivot elastic deformation and its stiffness are calculated using Hertz Contact Theory for various operating points of the rotor-bearing system. The finite element method is adopted to simulate the static coefficients of the fixed-tilting pad bearing, obtaining its oil film pressure distribution varied with the bearing eccentricity ratio. The corresponding dynamic stiffness and damping of the oil film are solved using partial derivative method. In addition, a special interest is put in investigating the effect of the series complex stiffness of the oil film and pad pivot, according to which, the equivalent dynamic characteristics are obtained. The results show that the relation between these two factors are complex and interactive, both of which have a significant influence on the static and dynamic performance of the bearing.

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Evaluation of the Thermal Effects in Tilting Pad Bearing

International Journal of Rotating Machinery ◽

10.1155/2013/725268 ◽

2013 ◽

Vol 2013 ◽

pp. 1-17 ◽

Cited By ~ 10

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.

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

Lubricants ◽

10.3390/lubricants9020018 ◽

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.

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