Yasuhiro Katoh

Experimental and Numerical Investigations of Endwall Flow in a Bowed Compressor Cascade

Detailed experimental and numerical investigations are performed to understand threedimensional flow fields, especially corner stall phenomena, in a bowed-stacking compressor cascade. The experimental and numerical results of the flow fields around the bowedstacking blade are compared with those of a straight-stacking blade. The numerical results of the straight-stacking blade indicate that two counter-rotating vortices exist near part of the blade suction surface. The calculated flow of the bowed-stacking blade shows that its existing vortex is weak, because the blade loading of the bowed-stacking blade in the endwall region is lower than that of the straight-stacking blade. When the aerodynamic loading is increased, three vortices are formed near the corner stall region in the straight-stacking blade flow fields, while the number of the vortices decrease to two near the corner stall region, a vortex is formed near the leading edge.

Development of a Transonic Front Stage of an Axial Flow Compressor for Industrial Gas Turbines

This paper describes the aerodynamic blade design of a highly-loaded three-stage compressor, which is a model compressor for the front stage of an industrial gas turbine.Test results are presented that confirm design performance. Some surge and rotating stall measurement results are also discussed.The first stator blade in this test compressor operates in the high subsonic range at the inlet. To reduce the pressure loss due to blade surface shock waves, a shock-free airfoil is designed to replace the first stator blade in an NACA-65 airfoil in a three-stage compressor. Comparison of the performance of both blades shows that the shock-free airfoil blade reduces pressure loss.This paper also presents some experimental results for MCA (multi-circular arc) airfoils, which are used for first rotor blades.Copyright