Sub-Synchronous Shaft Oscillations due to Oil Supply

This paper aims at the modelling and investigation of unstable journal bearing with an emphasis on instabilities such as oil-whirl or further induced oil-whip. For this reason, a test rig for the investigation of these phenomena was built. Geometry, parameters and operating cases of the rig are described in detail in the presented paper. Computational analysis of the test rig was performed using two methods — the finite element method and a multi-body approach. The calculations of pressure distribution in journal bearings were also performed applying two methods — the finite difference method and the finite element method. The results of the analysis are properly introduced and discussed at the end of this paper. The results suggest that a yet unknown sub-synchronous component may appear under specific conditions. The component typically appears at frequency 0.9–0.98 of shaft speed and is likely caused by a location of a bore for oil supply.