Performance Improvement of A Low Aspect Ratio Axial Flow Compressor Rotor by Means of Turbulence Generator

Abstract

The present paper reports results of an experimental investigation aimed at improving the performance and operating range of an axial flow compressor using a simple passive means. A total of four configurations are tested, namely, (i) basic rotor configuration without any passive means, (ii) rotor with modified partial shroud (MPS), (iii) rotor with MPS and turbulence generator, TG, placed on the casing at the leading edge of the rotor blade and (iv) rotor with MPS and turbulence generator, TG1, placed on the casing at 44 mm upstream of the leading edge of the rotor blade. The turbulence generators are made of velcro tape. The rotor performance is determined by measuring static pressure on the casing, upstream and downstream of the rotor blade. In addition, five hole probe traverses are made at the rotor exit at five flow coefficients (at, above and below design flow coefficients). From the casing static pressure measurements, stall flow coefficient of rotor (with MPS + TG1) is found to be decreased. From the five hole probe measurements, rotor (with MPS + TG1) is found to have improved total and static pressure coefficients compared to rotor (with MPS). Slightly reduced performance of this rotor compared to the basic configuration is attributed to the adverse effects of MPS. The improved performance of the rotor (with MPS + TG1) is attributed to the energization of the casing wall boundary layer at the rotor inlet, due to vortexes generated by TG1.