Bush-Driving Torque in Inner Oil Film of Floating Bush Journal Bearings with Numerical Analysis for Multiphase Flow Applied

摘要

Floating bush journal bearings are widely used to support small-sized high-speed rotating machinery. Bearings show the following peculiar phenomena when the supplied pressure is low. That is, the bush-to-journal speed ratio decreases, and the disappearance of the oil whip may be observed as the journal rotational speed increases. These actions could be explained qualitatively when the model with the axial oil film rupture being considered is applied to the inner oil film of the bearing. However, predictions are in quantitatively poor agreement with the measurements. This paper aims at predicting the bush-driving torque of the inner oil film by using the cubic-interpolated pseudoparticle (CIP) method that has been developed in the numerical analysis of the multiphase flow. It is found that the predicted torque is much smaller than the torque obtained from the previous model when the journal speed is high. This results from the incursion of the air into the film from the bearing side end. We also show the effect of some design variables, such as surface tension (which cannot be incorporated in the previous model) on the torque.