NUMERICAL INVESTIGATION OF BLOCKAGE DEVELOPMENT IN AN AEROENGINE TRANSONIC AXIAL COMPRESSOR STAGE

摘要

Numerical simulations have been carried out to quantify the development of flow blockage along the rotor and stator of a transonic compressor stage using the boundary layer thickness deducted from the boundary layer theory. The radial profiles of blockage have been obtained at different axial planes starting from the rotor leading edge and ending with the stator trailing edge. Three operating points at design speed have been used in the analysis to identify the regions where blockage is sensitive to the reduction of the mass flow rate. These conditions correspond to the maximum efficiency, a high total pressure ratio point prior to the maximum pressure, presumably a pre-stall point, and the last numerically stable point which might correspond to a post stall point. The results show that the rotor casing region exhibits high radial blockage at all operating points due to the shock induced separation of the rotor casing boundary layer. At the stator while the flow travels along the passage, a considerable radial blockage growth is observed when the mass flow is reduced due to massive separations near the stator hub. The overall planar blockage along the compressor stage shows a major blockage growth at the stator trailing edge when approaching the reduced mass flow conditions. The results suggest that the contribution of stator stall in the compressor stalling process should not be disregarded.