Investigation of the wake vortex shedding and the pulsant flow between rows of a centrifugal compressor

Numerical simulation of the three-dimensional unsteady viscous flow field of a transonic centrifugal compressor with vaned diffuser was performed. The vortex shedding near the impeller trailing edge was described. Spectrum analysis on 4 typical locations and the pulsant kinetic energy of 2 locations downstream the impeller trailing edge were provided. The study showed that the vortex shedding of the main blade and the splitter did not take place at the same time, but alternatively. The flow pulsated at the impeller trailing edge mainly because of the rotor/stator reaction and the vortex shedding. The two factor interacted as time went on. At the impeller exit, the flow pulsated mainly in the tangential direction and decreased with the increase of the radius. The intensity of the pulsant flow was different at the impeller exit.