Numerical Investigation of a New Unsteady Control Method to Suppress Tip Clearance Flow in Compressors

Passive Periodic Excitation Case (PPEC), a new unsteady flow control method to suppress tip clearance flow in compressors, is proposed in this paper. Because of the rotation of the compressor rotor, this passive flow control method with a static mechanism on the casing can produce a periodic excitation to the flow field. The numerical research of PPEC based on a centrifugal compressor rotor is finished, which confirms the effectiveness of PPEC and proves the superiority of this new unsteady control method. In addition, the investigation of tiny transient vortex structures in a plane cascade passage using PPEC is carried out, which to some degree reveals the deeper mechanism of PPEC.