Experimental Investigations of the Aerodynamics of Highly Loaded Tandem Vanes in a High-Speed Stator Cascade

Abstract

Tandem blade configurations are said to being able to outperform conventional single blades in terms of loss behaviour and flow turning. The work presented here is supported by experimental investigations which were conducted at a 2D linear stator cascade at the Chair for Aero Engines at the Technische Universität Berlin. Two different tandem blade configurations with a different load split are examined and compared against a conventional single reference blade. Multi-coloured oil flow visualisation complemented by wake flow measurements show the development of the secondary flow structures and enable a thorough understanding of the impact of varying tangential displacement for tandem blades. The results show that tandem blades can reduce the total pressure losses, especially in the midspan region, which also results in smaller overall values. In addition, the incidence angle variation has shown that the working range of the tandem vanes exceeds the originally designed working range of the single reference blade. The tandem configurations still allow flow guidance at stall condition and prove the capability of the concept.