Transient CFD Analysis of Multi-Lobe Bearings at 60000RPM for A Gas Turbine

Abstract—In this paper the problem of a 3 lobe bearing was selected which had the lobes placed at a distance of 120 degrees for transient CFD analysis . The rotation speed of the shaft was considered to be 60000 rpm. The results show that the presence of lobes highly affect the performance of the multi lobe bearing as the critical quantities developed here are comparatively lesser to the other zones in the bearing. The unsteady analysis was carried with help of Ansys Fluent software. In this study , six time steps of 10, 30, 50, 70, 90 and 100 seconds are taken respectively. After 100 seconds the unsteady condition becomes steady. After 100 seconds the maximum values of static pressure, total pressure, static temperature and total temperature are 7.68e+06 Pascal, 440 K are respectively and becomes steady. The study concludes that at high rotational speeds, lobes must be given in bearings to have a good life span of the bearing.