Prediction of Centrifugal Compressor Performance From Choke Through Stall With a Physical Throttle

Numerical simulation results of the internal flow field of a centrifugal compressor with vaneless diffuser are presented by solving three-dimensional Reynolds averaged compressible NS equations using CFD software CFX. A physical throttle added at the downstream of the volute has been successful in stabilizing the flow at all flow rates. Ambient conditions are held fixed at both the inlet and exit of the domain. Numerical results of an investigation in which the predicted aerodynamic performance of the centrifugal compressor with vaneless diffuser is compared with the measured experimental data over the entire design speedline from choke through stall are presented. Performance curves of different components are also presented. A physical throttle approach for the prediction of the unsteady flow physics that lead to stall is proposed and a series of unsteady-flow simulations are used to illustrate the instability flow physics in the impeller, the vaneless diffuser and the volute.