Experimental investigation of oilfilm behaviour in short journal bearings

Abstract

This report contains the description of the test apparatus that was designed and built for experimental investigation of oilfilm behaviour in short full-journal bearings of circumferential feed groove type. An account of the engineering problems solved in connection with the design and development of the apparatus is also given. Complete pressure distributions were obtained for a two inch diameter, one inch long bearing operating at 3500 rpm under 30 and 60 lb. applied loads and with various axial pressure gradients and supply pressures. The results are presented in graphical form and a comparison is made with the short bearing theory developed by F. W. Ocvirk. Agreement with theory was found to be very good when operating with low axial pressure gradient and high supply pressure (cavitation completely suppressed), while with high axial pressure gradient substantial differences in pressure distribution were found. Visual observations of oilfilm behaviour were made with a transparent plastic bearing of the same proportions, operating with a 60 lb. load at 3500 rpm. Cavitation behaviour under various axial pressure gradients and supply pressures is discussed, and photographic records of typical cavitation behaviour are presented in the report. Eccentricity and attitude angle measurements were made in all tests and experimental results are presented with pressure distribution data and cavitation behaviour records.