Active rotordynamic stability control by use of a combined active magnetic bearing and hole pattern seal component for back-to-back centrifugal compressors

Active control methods of rotordynamic stability for rotordynamic systems have been developed for many years, however effectively implementing these methods in real machines remains a significant challenge. With the goal of improving the performance of a back-to-back centrifugal compressor, a new integral electromagnetic actuator that combines the functions of an active magnetic bearing with a hole pattern seal is designed and used to replace the original balance piston of the machine. The structure design and assembly in the compressor are presented and an investigation on the seal performance and magnetic bearing forces is carried out. The results show that this innovative integral actuator can provide both sealing and vibration control, with two vibration feedback control methods experimentally validated for the elimination of oil whip, improving the rotordynamic stability of the machine.