Sub-Synchronous Vibrations of a Rotor Supported on Poorly Lubricated Journal Bearings

Abstract

This paper aims to the modelling and investigation of sub-synchronous vibrations of a rotor supported on poorly lubricated journal bearings. Bores for an oil supply are located in the lower halves of bearing shells. It is shown that the poor lubrication of the described bearings may lead to an occurrence of stable vibrations at the frequency ca. 0.9 to the rotor speed. Simulations are performed using a multi-body approach for modelling rotating systems. Forces acting in journal bearings are evaluated employing a massconserving finite element solution of the Reynolds equation.