CFD ANALYSIS OF COMPRESSOR BLADE CASCADE

Abstract

Efficiency is the key design parameter in today’s aeronautical engine industry. In axial compressor blades, the leading edge is the crucial part its geometry and the way it interacts with the incoming wakes has decisive effects on the boundary layer characters and therefore on the loss. This work aims to investigate the effect of the leading edge geometry on the performances of a compressor stage. In particular, the interaction between the leading edge and the wake coming from the upstream blade row should be investigated. Gaining some understanding of the physics of this complex process and, more in general, of the behavior of the flow around the leading edge could lead to the design of optimized geometries with improved performances. In this work, three geometries have been tested: a high wedge angle blade (32°) with circular leading edge and two low wedge angle blades (15°) with circular and elliptic (3:1 axes ratio) leading edges, representative of real engine blades. Numerical investigations in a low speed axial compressor have been undertaken, using JAVAFOIL AND ANSYS [CFD] software. The reported results show that the leading edge geometry in order to avoid the leading edge separation bubble to appear, may lead to significant loss reduction. A high wedge angle and an elliptic shaped leading edge proved to be able to achieve this. A comparison with the test case with circular leading edge and low wedge angle showed a 25% drop in the loss coefficient. This result gives an idea of the improvement offered by the research on compressor leading edges.