Influence of axial gap on compressor passage blockage and aerodynamic performance

In order to investigate the influence of the axial gap between the rotor and the stator on the flow blockage in a single-stage axial flow compressor and its aerodynamic performance, the unsteady three-dimensional multi-passage numerical simulations were carried out to investigate the flow fields of the compressor with five different rotor/stator gaps. The computational results show that in any case of the five different rotor/stator gaps, when the compressor is operating below the critical mass flow, the flow blockage zones are mainly located near the trailing edge of the rotor blade suction surface and in the rotor blade tip clearance region as well as in the hub and suction surface corner region of the stator. Moreover, with the same mass flow, when reducing the axial gap between the rotor and the stator, the flow blockage near the trailing edge of the rotor blade root suction surface becomes larger, however, the volume of flow blockage zone decreases in the rotor blade tip clearance region as well as in the hub and suction surface corner region of the stator, and thus the total volume of the flow blockage zones in the compressor becomes smaller. This is followed by an increase of the static pressure rise capability and the stable operating range as well as the adiabatic efficiency of the compressor. The research shows that with the same mass flow, as the axial gap decreases, the axial momentum of the main flow in the rotor blade tip clearance region increases, and that of the rotor tip leakage flow reduces. The result is that the volume of flow blockage zone in the rotor blade tip clearance region decreases. © 2015, Press of Chinese Journal of Aeronautics. All right reserved.