Heat Transfer in a Transonic Turbine Stage

In this study, the effect of nozzle guide vane trailing edge cooling on rotor heat transfer in a transonic turbine stage is investigated. Previous measurements taken in the MIT blowdown turbine facility have shown that nozzle guide vane cooling brings about an increase in the rotor pressure side heat transfer. A computational code (UNSFLO) was used to isolate the cause of the increased heat transfer on the rotor pressure surface. Two versions of UNSFLO were used so that the relative importance of nozzle guide vane wake temperature versus coolant mass addition on the heat transfer to the rotor could be investigated. The first version of the code did not include mass addition, with the decreased temperature of the wake being simulated by lowering the nozzle guide vane blade temperature. The second version of the code allowed coolant mass addition at the location of the coolant slots on the nozzle guide vane. The first version of the code did not correctly predict the increase in rotor pressure side Nusselt number due to nozzle guide vane cooling. It was determined that the decreased wake temperature did not alter the shock and wake structures in the flow, and wa