Oil flow, cavitation and film reformation in journal bearings including an interactive computer-aided design study

An interactive computer program for the design of steadily loaded fluid film, hydrodynamic journal bearings based on the procedure of E S D U Item No. 66023 (1966) is presented. The program was developed in two forms, a graphics and a non-graphics version. The program procedure enabled a detailed study of the effect of changes in the parameters on the bearing performance, which in turn permitted the design of an optimized bearing.

A theoretical and experimental study of the influence of film reformation on the performance of hydrodynamic journal bearings, and the side flow rate in particular, is also presented. A numerical analysis technique based on a cavitation algorithm proposed by H.G. Elrod was developed. This technique was capable of an automatic determination of the boundaries of the cavitation region and included a consideration of the lubricant inlet conditions (groove geometry and supply pressure). Theoretical data for journal bearings with a single axial groove located at the position of maximum film thickness is presented for a wide range of the values of the bearing design and operating parameters.

An apparatus was designed and commissioned to study the lubricant flow rate in journal bearings. Tests were performed with three glass bushes of width-to-diameter ratio of unity at variable values of eccentricity ratio and lubricant supply pressure. The agreement achieved between theory and experiment for dimensionless side flow rate was excellent. For the location of the film reformation boundary, the correlation between theoretical predictions and experimental measurements was satisfactory, except at low values of eccentricity ratio and dimensionless supply pressure. A study of the correlation between the predictions of dimensionless load capacity, attitude angle and dimensionless side flow rate obtained from ESDU Item No. 66023 (.1966) and those of the new bearing analysis reported in the thesis is presented. Good agreement was observed for the predictions of side flow rate.