Computational Analysis of Stall and Separation Control in Centrifugal Compressors

Abstract

A three-dimensional compressibleNavier ‐Stokes code has been used to model thesteady and unsteady e owe eld within a low-speed centrifugal compressor cone guration tested at NASA Lewis Research Center. Near-design conditions, the performance map, pressure e eld, and the velocity e eld were in good agreement with measured data. At off-design conditions, the calculations show that e ow reversal e rst occurs near the blade leading edge. If leftunchecked,thereversed-e owregiongrowsspatiallyandtemporally.Injectionofairupstreamofthecompressor face was found to modify the local e ow near the blade leading edge and to suppress rotating stall and surge. Even a moderate amount of air, typically around 5% of the total mass e ow rate, was sufe cient to extend the useful operating range of the compressor.