Numerical Investigation of Dynamic Characteristic of Surge in a Centrifugal Compressor

In order to elucidate the mechanism of the development of deep surge, a low-speed centrifugal compressor with a vaned diffuser is chosen to conduct whole-passage numerical investigation of the system dynamic characteristic and detailed flow field by technique of CFD. First, the system model of lumped parameter and the unsteady simulation results are combined together to analyze the system characteristic of the stage at different process of the deep surge cycle, which consists of positive deceleration, flow reverse, positive acceleration and plenum recovery. Second, after the comparison of detailed flow field at the same low mass flow rate of positive deceleration and positive acceleration region, there exists obviously difference about the characteristic of the diffuser flow field and the pulsation of the mass flow rate can promote or suppress the development of the diffuser stall. The whole-passage simulation can help advance the understanding of the flow characteristic in the process of deep surge, which can be used to develop the surge model with more accuracy and determine the effect of surge on downstream component.