Redesign and Performance Analysis of a Transonic Axial Compressor Stator and Equivalent Plane Cascades With Subsonic Controlled Diffusion Blades

Abstract

In order to verify a new controlled diffusion blade design concept, the stator of an existing transonic axial compressor stage was redesigned. Stator and equivalent cascade tests revealed the potential of such blades for a considerably higher aerodynamic loading than it has been applied up to now. The design procedure is described, and the results of plane cascade and stage testing are submitted, including performance analysis of both cascade and stator blade sections, at design and off-design operating conditions. The blade profile shapes and cascade geometries were calculated by means of an inverse, two-dimensional method taking also into account the axial velocity density ratio (AVDR). This design concept is essentially based on prescribed blade pressure distributions, which are optimized with respect to the blade boundary layer development. The flow phenomena are illustrated by means of loss and flow turning investigations, blade pressure distributions, and laser velocimetry data. The test results reveal that the two-dimensional approach applied is quite promising for the three-dimensional blade design. Finally, overall and blade element performance comparisons between the original NACA 65 profiled stator and the redesigned one demonstrate the favorable flow behavior of the new stator, as well as the great potential of the controlled diffusion blade concept.