Loss reduction in a high-speed compressor cascade using an L-shaped endwall groove to generate a streamwise vortex

Reducing the endwall loss is essential for the development of high-efficiency aero-engine compressors. An advanced vortex generation technique, using an L-shaped groove in the endwall, has been applied to a high-speed linear compressor cascade to manipulate the complex endwall flow and hence reduce associated aerodynamic loss by means of an induced streamwise vortex. A geometry generation method for the L-shaped endwall groove has been developed for the purpose of facilitating the design of the L-shaped groove. Hereafter, the L-shaped endwall groove has been optimized through a surrogate-based optimization framework. The numerical results demonstrated that the optimal L-shaped groove could control the endwall flow effectively and achieve a significant loss reduction at all operating points that were considered. At the design point, the calculated total pressure loss coefficient was decreased by 17.9%, with the static pressure rise increasing by 5.53%. The flow underturning and loss away from the endwall were reduced, while the flow overturning and loss near the endwall increased. The analysis of the flow control mechanism indicated that the groove separation vortex, i.e. the streamwise vortex generated by the L-shaped endwall groove, presented a barrier to the endwall cross flow, mitigating the interaction of the endwall fluid with the suction side of the blade. (c) 2022 Elsevier Masson SAS. All rights reserved.