Evaluation of pump seal and bearing characteristics by a rotor dynamic test stand with active magnetic bearings

摘要

A rotor dynamic test stand equipped with active magnetic bearings was developed for evaluating fluid reaction forces on annular pressure seals and bearings. The magnetic bearings enable control of eccentricity and whirl radius of rotors towards the seal center, thus making it possible to measure dynamic properties under totally non-contact conditions. Consequently, small fluid reaction forces of annular grooved seals can be measured with precision. Such favorable measurement conditions also make it possible to conduct experiments on hydrodynamic tones from annular grooved seals. Leakage velocities through narrow seal clearances and fluid film dynamics can be measured by this test stand and the data effectively used for boosting pump performance and vibration prevention. Experimental results on basic cavity noise characteristics and the mechanism are discussed, as well as properties that need to be estimated prior to determining the design of pump rotors.