Investigation on application of blended blade and endwall technique on radial diffuser

The corner flow separations in radial diffusers are more and more serious. So they have become the key restrict factors for higher efficiency and wider surge margin designs. Blended blade and endwall is a new technology for organizing and controlling the corner flow separations. Firstly, numerical simulation was carried out on a high pressure ratio centrifugal compressor stage with radial airfoil diffuser and the detail flow field analysis was conducted. Secondly, based on the performance results, it can be found that the BBEW design applied on suction side of diffuser delays and reduces the corner separations and improves the peak efficiency 0.4%, the near choked efficiency 0.7%. The pressure ratio increases slightly and the surge margin is not affected. Last, the varieties of corner flow structure under the action of BBEW are demonstrated and the action mechanisms are given.