Temperature Predictions and Comparison With Measurements for the Blade Leading Edge and Platform of a 1 1/2 Stage Transonic HP Turbine

Abstract

A series of computational predictions generated using FINE/TURBO are compared with data to investigate implementation techniques available for predicting temperature migration through a turbine stage. The experimental results used for comparison are from a one-and-one-half stage turbine operating at design-corrected conditions in a short-duration facility. Measurements of the boundary conditions are used to set up the computational models, and the predicted temperatures are compared with measured fluid temperatures at the blade leading edge and just above the blade platform. Fluid temperature measurements have not previously been available for these locations in a transonic turbine operating at design-corrected conditions, so this represents a novel comparison. Accurate predictions for this short-duration turbine experiment require use of the isothermal wall boundary condition instead of an adiabatic boundary condition and accurate specification of the inlet temperature profile all the way to the wall. Predictions using the harmonic method agree with the temperatures measured for the blade leading edge from 65% to 95% span to within 1% normalized temperature data. Agreement over much of the rest of the leading edge is within 5% of the measured value. Comparisons at 5–10% span and for the blade platform show larger differences up to 10%, which indicates that the flow in this region is not fully captured by the prediction. This is not surprising since the purge cavity and platform leading-edge features present in the experiment are treated as a smooth hub wall in the current simulation. This work represents a step toward the larger goal of accurately predicting surface heat-flux for the complicated environment of an operational engine as it is reproduced in a laboratory setting. The experiment upon which these computations are based includes realistic complications such as one-dimensional and two-dimensional inlet temperature profiles, a heavily film-cooled vane, and purge cooling. While the ultimate goal is to accurately handle all of these features, the current model focuses on the treatment of a subset of experiments performed for a one-dimensional radial inlet temperature profile and no cooling.