Tilting-pad journal bearing design considering rotordynamic stability and bearing performance

This paper introduces a process for designing a bearing that satisfies both rotordynamic stability and bearing performance using dimensionless bearing data. The dimensionless data of the tilting-pad journal bearing, calculated using a numerical model, is dimensioned considering thermal effects through a heat balance model. The dimensionless data is generated by considering variables such as the number of pads, preload, length-diameter ratio and load direction. Using the dimensioned static characteristics, the minimum film thickness and maximum operating temperature of the bearing are calculated. The dynamic characteristics of the bearing are applied to a rotordynamic model, and stability is compared using indicators such as separation margin, maximum vibration amplitude and amplification factor in rotor-dynamic stability analysis. To consider various design parameters, a bearing for an actual shaft system model was designed using the multi-grid method, and the influence of design variables was investigated.