Dynamic behaviour of oil film journal bearings in turbulent regime.

Abstract

In this paper, the dynamic behaviour of oil film journal bearings in turbulent regime is theoretically investigated based on the nonlinearized treatment. The dynamic oil film forces considering the combined effects of turbulence and fluid inertia forces are analytically obtained under the short bearing assumption. The nonlinear equations of motion for a rigid rotor supported horizontally in two identical aligned oil film bearings are solved by the improved Euler's method forward in time. The relations between journal center trajectory and transient pressure distribution are examined for Reynolds numbers of Re=2 750, 4 580 and 5 500 and for the length-to-diameter ratio of L/D= 0.5. It is found that the fluid inertia forces have an advantage of improving the dynamic behaviour of turbulent journal bearings under certain operating conditions.