Model validation for an AMB-based compressor surge control test rig

In this paper, we present experimental test data for validation of a recently introduced mathematical model for compression systems, including the dynamic effects of varying the impeller axial tip clearance. For the centrifugal compressor test rig that was built to study the suppression of surge by using active magnetic bearings (AMBs) to control its impeller tip clearance, the steady state and the dynamic response of the compression system induced by varying the impeller tip clearance are measured and compared to theoretical predictions, and the states of the compression system in surge condition are collected and analyzed. Parameters in the compression system model, such as the Greitzer parameter B and Helmholtz frequency ¿_H are experimentally identified. Also, the servo dynamics of the magnetic bearing that controls the axial impeller position is determined experimentally.