OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
INVESTIGATIONS OF THE VARIATION OF BUSH TEMPERATURE
OF AN OFFSET-HALVES JOURNAL BEARING PROFILE
Amit Chauhan
Department of Mechanical Engineering, UIET, Panjab University, Chandigarh-160014, India,
E-mail: drchauhan98@gmail.com, Mob. +91-9463703366
Abstract
The analysis of offset-halves journal bearing has been carried out to find out the rise in bush temperature by
evaluating the oil-film temperature using parabolic temperature profile approximation technique. It has been
observed that the bush temperature increases with increase in speed and the same trend observed in both upper
and lower lobes of the bearing. During simulation, the bush temperature observed to be of increasing nature
with increase in eccentricity ratio in lower lobe whereas of little decreasing nature with increase in eccentricity
ratio in upper lobe of the bearing. Hence, it can be concluded that rise in bush temperature is considerable and
comparable. Therefore, it should be taken into consideration while designing offset-halves journal bearing.
Keywords: Offset-halves bearing, bush temperature, and Parabolic Temperature Profile Approximation.
1. Introduction
Hydrodynamic journal bearings find an extensive use in high speed rotating machinery. Under the normal
operating conditions, these bearings usually experiences a considerable variation in bush and oil-film
temperature due to viscous heat dissipation. This change in temperature significantly affects the bearing
performance as lubricant viscosity is a strong function of temperature and, hence, leads to failure of the bearing.
Thus, computation of oil-film and bush temperature is of great importance to predict bearing performance
parameters. The non-conventional journal bearings, like lobed bearings and tilting pad bearings have a common
feature that these bearings operate with more than one active oil film which accounts for superior stiffness and
damping characteristics of these bearings as compared to the conventional circular bearings. The offset-halves
journal bearing is commonly used as a lobed bearing in which two lobes are obtained by orthogonally displacing
the two halves of a cylindrical bearing (Fig. 1) and frequently used in gear boxes connecting turbine and
generator in power generation industries.
Fig. 1 Schematic diagram of offset-halves journal bearing
Offset-halves journal bearings show stiffness and damping properties which permit light loads at high rotational
speeds [1]. The importance of thermal effects in hydrodynamic journal bearings has been long recognized, but
very limited study about thermal effects in lobed bearing especially offset-halves bearing has been reported in
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