Wake of a Compressor Cascade with Tip Gap, Part 1: Mean Flow and Turbulence Structure

Abstract

The purpose of this work is to understand the structure of the vortex-dominated endwall flows found in aircraft engine fans and compressors. Our approach is to model the flow using a linear cascade where detailed turbulence measurements can be made and the relative motion between blade tip and casing can be simulated. The cascade consists of eight 4% thick modified circular-arc blades and operates at a chord Reynolds number of 3.88 × 10 5 with a thin inlet boundary layer and 12.5 deg of turning. We present baseline results for the tip-leakage flow with stationary endwall. Three component velocity and turbulence measurements are used to reveal the evolution of the flow as a function of distance downstream of the blades for a tip gap of 1.6% chord and as a function of tip gap from 0.8 to 3.3%