Effect of Axial Spacing Between Stator and Rotor on Turbine Performance

摘要

Unsteady effect of rotor-stator interaction on turbine stage performance was investigated fortwo cases of axial spacings between stator and rotor, i.e. large and small axial spacings. UnsteadyRANS simulations were performed to clarify several interesting features of the unsteady threedimensionalflow field in the turbine stage. Simulation results showed that the stator wake wasconvected from pressure side to suction side in the rotor. As a result, secondary flow was periodicallygenerated by the wake passing through the rotor passage, and then the passage vortices in the rotornear the endwall were suppressed and fluctuated in the radial direction downstream of the rotor. Itwas found that turbine stage efficiency with the small gap was higher than that with the large gapbecause the wake entered the rotor before mixing.