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1 – 3 of 3Shun Wang, Qingchang Tan and Zunquan Kou
The purpose of this paper was to construct lubrication model closer to the fact of thrust bearings and to calculate the bearings characteristics of lubrication for understanding…
Abstract
Purpose
The purpose of this paper was to construct lubrication model closer to the fact of thrust bearings and to calculate the bearings characteristics of lubrication for understanding how structures influence bearings performances and, importantly, what can be the most beneficial. Large-scale composite thrust bearings with Polytetrafluoroethylene (PTFE)-faced sector pad backed by steel base are used increasingly in equipment. But there are plenty of puzzled problems in design and application.
Design/methodology/approach
The authors established a 3D thermal elastohydrodynamic lubrication (TEHL) model. Oil film was formulated by Reynolds equation for pressure, and by energy equation for temperature varying through oil film thickness. Meanwhile, pad temperature was formulated by solid heat transfer equation. Elastic and thermal deformations of pad surface were calculated. Viscosity and density of oil were valued separately under different pressure and temperature. Load balance was considered as well as overturning moment balance. Finite difference method was applied to discrete these equations.
Findings
PTFE layer and steel base have either helpful or detrimental impact on contact strength and full film lubrication of thrust bearing depending on their relationship in thickness. Temperature lag between middle layer of steel base and pad surface depends on PTFE layer, but not on the steel base. PTFE layer thickness should be considered when alarming threshold value of the bearings temperature is chosen.
Originality/value
Three-dimensional TEHL model of large-scale composite thrust bearings was established, which included more factors close to the actual. Conclusions were drawn. These proposals are helpful to design the bearings.
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Keywords
Liming Zhai, Yongyao Luo, Xin Liu, Funan Chen, Yexiang Xiao and Zhengwei Wang
The purpose of this paper is to analyze lubrication characteristics of a tilting pad thrust bearing considering the effect of the thermal elastic deformation of the pad and collar.
Abstract
Purpose
The purpose of this paper is to analyze lubrication characteristics of a tilting pad thrust bearing considering the effect of the thermal elastic deformation of the pad and collar.
Design/methodology/approach
This study used the fluid–solid interaction (FSI) technique to investigate the lubrication characteristics of a tilting pad thrust bearing for several typical operating conditions. The influences of the rotational speed, the thrust load and the oil supply temperature on the lubrication characteristics were analyzed.
Findings
The three-dimensional (3D) film model clearly shows that there is no pressure gradient but large temperature gradients across the film thickness. The wall heat transfer coefficients on the pad surfaces distribute in a very complex way and change within a large range. The rotational speed, the thrust load and the oil supply temperature have great but different influences on the lubrication characteristics.
Originality/value
This paper has preliminarily revealed the lubrication mechanism of the tilting-pad thrust bearings. The 3D FSI method is suggested to evaluate the thermal-elastic-hydrodynamic deformations of thrust bearings instead of the conventional method which iteratively solves the Reynolds equation, the energy equation, the heat conduction equation and the elastic equilibrium equation. Using FSI method, the heat transfer coefficients on the pad surfaces can be evaluated better.
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Mouhcine Mouda, Mohamed Nabhani and Mohamed El Khlifi
This study aims to examine the magneto-elastohydrodynamic effect on finite-width slider-bearings lubrication using a non-Newtonian lubricant.
Abstract
Purpose
This study aims to examine the magneto-elastohydrodynamic effect on finite-width slider-bearings lubrication using a non-Newtonian lubricant.
Design/methodology/approach
Based on the magneto-hydrodynamic (MHD) theory and Stokes micro-continuum mechanics, the modified two-dimensional Reynolds equation including bearing deformation was derived.
Findings
It is found that the bearing deformation diminishes the load-capacity and increases the friction coefficient in comparison with the rigid case. However, the non-Newtonian effect increases load-capacity but decreases the friction coefficient. Moreover, the use of a transverse magnetic field increases both the friction coefficient and load capacity.
Originality/value
This study combines for the first time MHD and elastic deformation effects on finite-width slider-bearings using a non-Newtonian lubricant.
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