Numerical & Experimental Study On The Three Dimensional Flowfield Inside Centrifugal Compressor Stage

In recent years, the study of multistage internal flows has become one of the major research areas in turbomachinery aerodynamics. With the development of the numerical technology and computer, the combination of physical experiments and numerical computations has become one of major ways to analyze flow rules and phenomena in the centrifugal impeller.In this paper, the capability of one centrifugal compressor whose outer diameter Reynolds number is 5.9×106 and Ma number is 0.8 is measured and the performance parameters such as temperature, pressure, efficiency and ratio of pressure are obtained. The velocity field in the vaned diffuser is also measured using the five-hole pressure probe and the velocity magnitude of different axis surface at inlet and outlet is obtained. Combining with result of computation, the flow rules in vaned diffuser is analyzed.Applying the SIMPLEC algorithm in CFD software, multiple reference frame at rotor-stator coupled area in the compressor and wall function in the computation velocity and temperature at near wall, the flow field of centrifugal compressor was computed. In the same condition, the error between computation and experimentation is less than five percent.The distribution of velocity, pressure and temperature in several section of compressor are particularly analyzed, such as impeller, diffuser and circumfluence part. It provides important numerical evidence for the designment, improvement, and optimization of centrifugal compressor.It is found that changing the inlet setting angle of vaned diffuser can improve the flow condition and postpone separation for the sake of broad stability operation rang and high efficiency at different condition .