An enhanced Greitzer compressor model with pipeline dynamics included

The modeling of a centrifugal compressor system with exhaust piping acoustics is presented in this paper. For a centrifugal compressor test rig with modular inlet and exhaust piping, a mathematical model is derived based on the Greitzer compression system model. In order to include the dynamics of the piping acoustics, a transmission line model is added to the original compressor equations, and different compressor piping configurations are tested. The simulation of the resulting mathematical models of the compression system are compared to the measured response. Employing active magnetic bearings to perturb the axial impeller tip clearance of the compressor, the compression system is excited over a wide frequency range and the input-output response from the impeller disturbance to the plenum pressure rise is analyzed. A good agreement is observed between the experimental and theoretical Bode plots.