A Theory of Cavitation in an Oscillatory Oil Squeeze Film

Abstract

The cavitation of oil films in bearings subjected to dynamic loads is not well understood. In order to compute reliably the performance of dynamically loaded bearings, it is important to know the underlying mechanisms of the cavitation phenomenon and be able to predict its occurrence and subsequent development. From previous studies (Sun and Brewe, 1992; Sun, Brewe and Abel, 1993) the following features of cavitation in submerged bearings (i.e. with no air entrainment) are known: (1) Cavitation is confined to one region, which contains residual oil filaments of the fractured film. (2) The pressure in the cavitation region is the vapor pressure of oil. (3) Tensile stress is present in the oil film outside the cavitation region. (4) The occurrence of cavitation requires not only a low pressure level but also some other condition. In this paper a new cavitation model is proposed, that incorporates the above features, considers the effect of surface tension, and preserves mass conservation in the cavitation region. The model is applied to an oscillatory oil squeeze film bounded between two parallel circular plates, a problem that has been extensively studied in the past (Hayes and Feiten, 1964; Rodrigues, 1970; Parkins and May-Miller, 1984; Boedo and Booker, 1995; Optasanu and Bonneau, 2000). New results derived from the model are presented and compared with those of previous studies.