Stagnation Point and Surface Heat Transfer for a Turbine Stage: Prediction and Comparison With Data

Abstract

Predictions using turbulence models are reported for the time-averaged heat-flux distributions on the vane and blade surfaces of the Garrett TFE 731-2 HP and Teledyne CAE 702 HP turbines. To provide the proper initial conditions for the boundary layer solution, the stagnation point process starting from the far free stream is considered. The mean velocity and temperature and the turbulence variation along the stagnation streamline are predicted with a Reynolds stress model so as to resolve accurately the turbulent normal stresses that govern the production of turbulence in the stagnating flow. Using the results from the stagnation solution as initial conditions, the k –ε model equations in boundary layer form are solved at midspan for the pressure and suction sides of the vane and the blade, using a pressure distribution obtained from inviscid codes. The predicted surface heat transfer distributions are compared with measurements from short-duration full-stage rotating turbine measurements.