Estimation of Relationship between a Journal Bearing L/D Ratio and the Morton Effect by Regression

Abstract

Rotating machinery may become unstable with vibration due to increase of rotational speed. One cause of instability is a thermal bending phenomenon, called the Morton Effect, generated in a journal bearing. Recently, many numerical analyses and experimental studies on this phenomenon have been reported. However, an influence of design specifications in rotating machinery on the Morton Effect has not been clarified in these previous studies. In this research, authors estimate a relationship between a design parameter of journal bearing and the Morton Effect by regression. Authors focus on the ratio of the bearing length and the bearing inner diameter“L/D ratio”as the design parameter. A dataset for regression is prepared by simulation instead of experimental data. As a result of the regression, it was estimated that the larger L/D ratio suppressed the vibration caused by the Morton Effect.