Interacting effects in a multistage axial compressor using shrouded and cantilevered stators

This paper describes the analysis of the flowfield in a four-stage low-speed axial compressor at the design point investigated both numerically and experimentally, with particular emphasis on the impact of stator hub flow leakage in a section of the machine featuring a change of stator configuration. The goal of the work is to give insight into the effect of the stator hub configuration on the aerodynamic performance in terms of loss and efficiency of downstream blade rows as well as the resulting stage matching effects. The investigation is focused on aerodynamic behavior and stage interaction, which the stator hub configuration of a given stage induces in a downstream stage with respect to its performance and flowfield. Two shrouded and one cantilevered stator hub configurations, such as those commonly employed in industry, are investigated and discussed with respect to local flow phenomena and stagewise aerodynamic effects. The results show that the stator hub configuration of a given stage has a drastically high impact on the downstream rotor aerodynamic performance, whereas the downstream stator as well as the upstream rotor are only slightly influenced by the stator hub configuration.