Maximum load capacity profiles for gas thrust bearings working under high compressibility number conditions

To meet the requirements of new commercial equipment, performances of air thrust bearings always have to be improved. This work is concerned with the research of the converging profile that will give high load capacities. When compressibility effects increase (when the compressibility number Lambda is over 50), a one-dimensional study shows that the best bearing is a composite bearing, i.e., one in which the leading portion has a constant slope followed by a surface parallel to the runner For each compressibility number, entrance film thickness H-1 and the transition angle theta(1) define the best profile. In a two-dimensional study, for compressibility numbers from 10 to 1000, comparison iii term of load capacity is made between tapered and composite profiles. If outlines the better load capacity of the composite bearings and confirms the good results obtained by Heshmat (1983) and Gray (1981) with such profiles.