Study of Effects of Rotor Tip Tailoring in Axial Flow Compressors

Abstract

The performance of an axial compressor rotor is known to be affected by the variations in tip clearance during its operation. This effect is pronounced for the rear stages of a multistage compressor. This paper describes a novel design that is shown to aerodynamically desensitize the rotor tip to the tip clearance variations. The effect of tip clearance variations on the performance of a baseline low speed, high hub-to-tip ratio axial compressor rotor is studied using CFD. Based on the understanding developed from this flow analysis, the baseline rotor is redesigned by tailoring the tip and redistributing the blade loading over the span. The tip tailoring results in a blade with split dihedral, i.e. of applied dihedral variable from the leading edge to the trailing edge. CFD analysis of the tip tailored configuration shows lower pressure drop with increasing tip clearance as compared to the baseline design. The simulation results are validated through testing in a low speed axial compressor rig, thereby giving experimental support to the desensitization of the rotor to the studied tip clearance variations by tip tailoring.