Oil Flow and Film Extent in Complete Journal Bearings

In 360-deg. journal-bearing theory, the load-carrying film is assumed to be partial as a result of cavitation in the diverging outlet film, but the friction-producing film is taken as complete. The effect of oil inlet conditions on film extent and the state of affairs prevailing in the cavitated film have been matters for speculation. A method has been developed for photographing the oil film in glass bearings of standard clearance ratio (0·001 and 0·002) and the results of a qualitative and quantitative examination of film extent are described. The measured oil outflow rates are analysed by separation into the hydrodynamic and supply-pressure-induced components, and explanations for an apparent deficit in the former are discussed.