Numerical Study Of Flow Field In A Centrifugal Compressor

Axial centrifugal combined compressor is often used as compressor part in medium and small turboshaft engines.The internal flow field of centrifugal compressor is affected by many factors and the flow is very complicated.How to design high pressure ratio and high efficiency centrifugal compressor is the research goal of researchers.Therefore,it is of great significance to analyze the internal flow field of centrifugal compressor,to understand the main flow losses and to optimize the blade profile for improving the pressure ratio and efficiency of centrifugal compressor.First of all,in this paper,in order to study the flow field of centrifugal compressor,the numerical simulations were carried out for a typical high pressure ratio centrifugal compressor SRV2 by NUMECA software in this paper and the flow fields around the blades were analysed.The results show that there are mainly three secondary flow structures exist in this centrifugal compressor: blade surface secondary flow,tip leakage secondary flow and tip passage secondary flow,respectively.These secondary flows interact to form a common jet wake structure in centrifugal compressors.Secondly,by calculating the effects of two different diffusers on the Ziegler impeller,it is concluded that the diffuser will affect the centrifugal compressor in front of it.The vaneless diffuser generally has less loss than other diffusers.The vaned diffuser makes the front row centrifugal compressor more prone to shock waves.The vaned diffuser can make the jet wake structure of the front row centrifugal compressor smaller,because the diffuser blade has an effect on the flow in front.Then,the overall performance of the centrifugal compressor is calculated by calculating the centrifugal compressor portion of an axial-flow centrifugal combined compressor.The effects of leading vanes and cascades in series on fluid flow in centrifugal impellers were observed.Finally,by studying the distribution of different tip clearances,the influence of the tip clearance on the performance of the centrifugal compressor and the influence on the internal flow field of the compressor are investigated.