Experimental investigations on tandem compressor cascade performance at low speeds

Abstract

Minimizing the number of axial flow compressor stages for a specific work output, and thereby lowering the engine size and weight, has always been the designer's goal. Recently, with the emergence of low aspect ratio blades, there has been a renewed interest in tandem blading for maximizing the blade loading further besides improving its off-design performance characteristics. This paper presents aerodynamic performance evaluations of three assorted cascades of single (CDA 43), tandem (CDA 21-21), and a newly developed tandem (CDA 32-21) blading. Fundamental investigation has been attempted in a low speed cascade wind tunnel to find the high deflection capability of tandem cascades. Although limited performance of tandem CDA 21-21 has been affected by certain grey areas covering both geometric and aerodynamic shortfall, tandem CDA 32-21 derived from CDA 43 and CDA 21-21 has shown high flow deflection characteristics and hence high loading over a wide range of angle of attack.