Influence of the Hub Endwall Cavity Flow on the Time-Averaged and Time-Resolved Aero-Thermodynamics of an Axial HP Turbine Stage

This experimental research investigates the influence of the hub endwall cavity flow on the aerodynamics and heat transfer of a high-pressure transonic turbine stage tested under engine representative conditions. The measurements include the hub and tip endwall static pressure downstream of the vane, the static pressure and heat transfer on the rotor blade at 15% span and on the hub platform as well as the stage downstream total pressure and temperature. Both steady and unsteady aspects are addressed. The hub endwall cavity flow has a significant influence on both the time-averaged and time-resolved components of the measured quantities. The effects are shown to be mainly due to an increase of the pitchwise averaged static pressure at hub downstream of the vane when cavity flow ejection is activated.