Numerical investigation on flowfield of centrifugal compressor with tandem cascade diffuser

The flowfield of the centrifugal compressor with tandem cascades diffuser was investigated numerically, the effects of varying circumferential position of tandem cascade diffuser on a high pressure ratio compressor performance and flowfield in the diffuser was discussed. The comparisons of the compressor stage performance and flow field of 5 tandem cascade diffusers with a conventional single row design of a similar duty were made. Results show that the performance of the stage with the tandem cascade diffuser is superior to the stage with single row diffuser, the efficiency and pressure ratio can increase 1.9% and 2.85% respectively. The circumferential position of the tandem cascade diffuser has an important effect on the stage performance; an optimum circumferential position exists to make the loss in the diffuser minimum. The loss in the tandem cascade diffuser mainly focuses on the region from the middle span to the shroud.