A Quasi-Unsteady Study on Wake Interaction of Turbine Stator and Rotor Cascades

Detailed flow measurements were made to study cascade interaction of turbine stator and rotor, using two linear cascades installed in series. The upstream cascade was moved to several places in the cascade pitchwise direction in order to change the relative location between the two cascades, and measurements were made in the downstream cascade. The result shows that the net total pressure loss generated in the downstream cascade becomes maximum when wakes of the upstream cascade pass the suction side of the downstream cascade passage, while the tip leakage loss generated in the downstream cascade does not change with the relative location of the cascades. The upstream cascade wakes interact with the secondary flows and most strongly with the endwall flow in the downstream cascade passage, making the loss distributions in the cascades fairly unsteady.