Suppression Effect on Corner Separation in Compressor Cascade by Bowed Blade

—Influence of Incoming Boundary Layer Thickness—

Abstract

In this study, the influences of the incoming boundary layer thickness on the suppression effects on the corner separation by the bowed blade were examined numerically. The test cascades were linear compressor cascades composed of straight blades and of bowed ones. The positive dihedral angles of the bowed blades at the endwall were varied from 10 deg. to 40 deg. at intervals of 10 deg. At an inlet boundary plane, a uniform velocity distribution and a non-uniform one with a 99% boundary layer thickness of 8.1% span were applied as a boundary condition. The computed results clarified the following trends: Compared with the typical straight blade, the present bowed blades suppress the corner separation regardless of the incoming boundary layer thickness. Meanwhile, the increase of the incoming boundary layer thickness decreases the most effective dihedral angle, at which the mass-averaged total pressure loss coefficient at the cascade outlet becomes minimum.