Numerical study on the influence of shroud cavity in the high-pressure centrifugal compressor for compressed air energy storage system

Abstract

As a key energy equipment of the compressed air energy storage (CAES) system, the centrifugal compressor with shroud cavity is employed to avoid the leakage flow from the rotor, especially in the high-pressure stages. In order to clarify the leakage characteristics and its influences, the high-pressure centrifugal compressor with shroud cavity is taken as the research object in the present work. First, the leakage flow across the shroud cavity has been studied numerically, it’s found that there are negative effects on the high-pressure compressor’s aerodynamic performance by the shroud cavity. And then, the flow characteristics inside the shroud cavity are showed by finding several secondary flow regions and cavity vortices. In addition, through the entropy contours and streamlines, the influence on the main flow by the leakage are analysed in detail. By analysing the influence of the shroud cavity on the high-pressure compressor, this paper can provide a practical guidance for the design of the impeller in the CAES system.