Aerodynamic test of fixed-geometry and adjustable additional blades in axial-flow compressor stage

An application of a flow control equipment in a compressor has been found to give a substantial improvement in the compressor stable operational range. The experimental investigation has been performed with additional blades (of a fixed-geometry and adjustable types) in an axialflow compressor stage. The fixed-geometry type additional blades were installed in the blade-toblade duct of a rotor hub and in hub and tip zones of a guide vane. Total pressure diagrams for the stage embodiments (with and without the fixed-geometry additional blades) are presented. The adjustable tip additional blades were tested in two configurations, along the full length of the rotor blade chord projection, and located only in the inlet part of the rotor blade. This experimental investigation revealed a special importance of the inlet rotor part in rotating stall occurring.