Three-Component LDV Measurements of Corner Vortices over Second- Generation, Controlled-Diffusion, Compressor Blades in Cascade

摘要

A detailed investigation of the three-dimensional flow in a cascade of second-generation controlled-diffusion compressor stator blades, at off- design inlet-flow angle, is reported. Three-component fiber-optic Laser-Doppler Velocimetry (LDV) surveys were made to fully map the flow at one plane upstream of the cascade and at three planes downstream. The measurements were performed at an inlet flow Mach number of 0.22 and a Reynolds number, based on chord length, of 640,000, The inlet surveys documented the approaching flow field in detail to establish the inlet boundary conditions for numerical simulations. At the downstream planes, total velocity distributions, total turbulence kinetic energy distributions, secondary flow velocity vector and contour plots are presented. The downstream surveys confined the existence of secondary flow vortices produced by the end wall. Surface vector and contour plots of non- dimensional velocity and total turbulence kinetic energy detail the complex flow field, including the size and location of the coiner vortex system.