12th European Conference on Turbomachinery Fluid dynamics & Thermodynamics
For this work, different shroud configurations of a LP turbine rotor and their influence on the tip leakage flow as well as on the main passage flow were experimentally and numerically investigated. The basic configuration of the LP rotor consists of a shroud with two straight sealing fins. Based on foregoing investigations in the basic setup, the geometry of the shroud was altered by drilling radially through the shroud in each rotor passage. The bore is located near the pressure side of the blade between the two sealing fins. The basic idea is to produce an aerodynamic blockage effect inside the shroud cavity and therefore reduce the cavity flow. The time-resolved measurement data from measurements with a Fast Response Aerodynamic Pressure Probe (FRAPP) downstream of the LP rotor is compared to results from CFD calculations. During the investigations it was found, that the radial bore not only influences the tip region downstream of the LP rotor, but also causes changes of the flow field close to the hub.