Experimental and computational investigation of flows in a vaned diffuser under stage environment
级环境下叶片扩压器流场的实验与数值研究

This paper presents experimental and computational results of flow in a vaned diffuser of a largesize centrifugal compressor stage to study unsteady interactive flows and verify the capability of CFD codes.Detailed instantaneous flow has been measured at several positions using a hot wire anemometer with Phase-Locked Ensemble Averaged technique.To quantitatively describe the unsteady effect induced by the impeller,an unsteady intensity is defined in this paper.The experiment shows that the unsteady flow in the vaneddiffuser is very complex,namely,the unsteady effect decays fast in the vaned diffuser with distance from theimpeller and persists in the diffuser outlet.For this tested centrifugal compressor,the periodic unsteadiness isweaker than the turbulent part in all unsteady flow in the vaned diffuser.Also,two computational investigationsfor the tested centrifugal compressor are performed and compared with corresponding experimental data:oneis a steady method with the deterministic stress model and the other is an unsteady method with the slidinginterface technique.Both numerical results are shown in good agreement with the experiment in the inlet planeof the vaned diffuser.