Jørgen W. Lund: Theories Versus Tests, Part 2: Damped Critical Speeds of Rotors and Fluid Film Bearing Characteristics

Abstract

Experiments are conducted on two rotors, weighing 40 and 187.5 kg, respectively, and supported in cylindrical bearings with two axial grooves. The journal position is measured in the bearing with built-in capacitance displacement probes, and the dynamic behavior is monitored with pressure probes. The self-excited whirl at the threshold speed of instability, as well as the influence of unbalance on the whirl frequency, is investigated in detail. By adding damping at the supports, the heavier rotor is stabilized and is operated up to 20,000 RPM. Correlation with the theoretical predictions is presented.