Control of Flow Separation in Adverse Pressure Gradients by Means of Crosswise Grooved Surfaces for Turbo Machine Applications

摘要

The total pressure losses in a compressor stage are strongly affected by sec-ondary flow effects such as corner separation. Experiments in a highly loaded com-pressor cascade were performed to minimize the losses using a grooved surface on the side walls under cross flow conditions. This geometry hampers the secondary flow in the cascade in such a way, that the corner separation is less pronounced. The total pressure losses are reduced by 9.8% and the flow turning angle is increased. The experiments were accomplished at Reynolds numbers up to Re = 0 56 · 10 (based on 40 mm chord of the vane profile) and Mach numbers up to M = 0.67. To understand the flow physics of the crosswise grooves, additional experiments at lower Reynolds numbers were performed.