Unsteady Aerodynamic Loads of Low-Pressure Turbine Under Rotor-Stator Interaction

In order to study the control effects of axial gap and trailing edge serrated structure on the unsteady aerodynamic loads of low-pressure turbine blades under rotor-stator interaction, the internal flow field of the last stage of the E3 low-pressure turbine is numerically simulated. The variation regularity of unsteady aerodynamic loads on the down-stream rotor blade surface is studied by changing axial gaps and adopting serrated trailing edge stator. The following facts are revealed: the unsteady aerodynamic loads on the rotor blades surface can be inhibited when increasing the axial gaps, because the blending of the wake and the mainstream can be enhanced with the increasing of the axial gaps, which results that the non-uniformity of the airflow is eliminated; the stator trailing edge serrated structure can not only strengthen the blending of the wake and the mainstream, but also change the vortex structure at the trailing edge, which will cause a destructive interference effect on the leading edge of the downstream rotor blades, lower its maximum load fluctuation by about 30%, reduce the speed loss in wake by 75.7 m/s, and improve the circulation capacity and time-averaged efficiency of turbine. Compared with the straight trailing edge stator, the serrated trailing edge stator blades can not only improve the rotor-stator interference effects and aerodynamic performance greatly, but also shorten the axial gaps of turbine by 10% without loss of the turbine efficiency. © 2020, Editorial Department of JVMD. All right reserved.