A Study of the Lubricant Film Characteristics of Journal Bearings : Part 3, Effects of the Film Viscosity Variation on the Dynamic Characteristics of Journal Bearings

Abstract

It is becoming increasingly important to determine the dynamic characteristics of journal bearings precisely for recent high speed rotatory machines. In this paper, the oil film spring and damping coefficients are calculated taking the effect of oil film viscosity variation into consideration. The theoretical results make clear the influences of the journal speed and bearing clearance ratio on these coefficients. The measured spring and damping coefficients vary with the journal speed, even though Somerfelds Number is equal. This phenomenon is well accounted for by the theory which deals with the effect of viscosity variation in the oil film.