EXPERIMENTAL AND ANALYTICAL STABILITY INVESTIGATION OF HIGH SPEED ROTORS SUPPORTED ON NOVEL INTERNALLY SKEWED JOURNAL BEARINGS IN A 60000 RPM TEST RIG

This paper presents the experimental and analytical stability investigation of high speed rotors supported on novel internally skewed journal bearings in a 60000 RPM test rig. The stability of turbocharger rotors has been widely investigated. Some expensive solutions for the stability of turbocharger rotors have been proposed, however this paper provides a simple bearing design with a skewed journal bearing that can be easily and simply applied to turbocharger rotors. In this paper the analytical model of the skewed journal bearings is first developed. Then the numerical analysis and the experimental stability results are provided for a 60000 rpm turbocharger test rig with a simple journal bearing, a floating ring bearing, and a skewed journal bearing. The skewed journal bearing showed superior stability characteristics both numerically and experimentally. In fact the test rig was stable with the skewed journal bearing up to the maximum speed of the test rig of 60000 rpm. The shaft centerline position in the bearings is also presented, as well as the power loss in the skewed journal bearings, thus providing a complete analysis of these internally skewed journal bearings. Design considerations are also discussed at the end of the paper.