The influence of diversified forward sweep heights on operating range and performance of an ultra-high-load low-reaction transonic compressor rotor

Abstract

To provide a guideline for the optimal selection of forward sweep height (FSH) in terms of operating range and performance, numerical simulations are utilized to investigate the effects of different FSHs on a new-type low-reaction ultra-high-load compressor rotor. The results illustrate that it is an effective measure to amplify stall margin improvement (SMI) by adequately increasing FSH (no more than 50% span). Nonetheless, when FSH exceeds 50% span, there appears a drop in SMI. Both total pressure ratio (TPR) and peak efficiency (PE) demonstrate a continual downward trend with increasing FSH. It is noteworthy that compared with the unswept rotor, forward sweep enhances stall margin in all rotors but reduces PE and the corresponding TPR when FSH is more than 50% span. There exists an optimal FSH (50% span) that could maximize SMI (15.12%) and simultaneously achieve a negligible performance change at PE condition. A deep insight into the flow field reveals that as FSH increases, the shock gradually migrates downstream and the separation bubble on suction side shrinks at PE point and shortens in streamwise direction near stall. If FSH continually increases above 50% span, SMI brought by the change in shock structure and tip leakage flow will drop.