APPLICATION OF SCALE ADAPTIVE SIMULATION MODEL TO STUDYING COOLING CHARACTERISTICS OF A HIGH PRESSURE TURBINE BLADE CUTBACK TRAILING EDGE WITH DIFFERENT COOLING CONFIGURATIONS

This paper adopted Scale Adaptive Simulation (SAS) to investigate fluid flow and cooling characteristics in detail downstream of a high pressure turbine (HPT) blade trailing edge (TE) cutback region. The effects of typical TE configurations on cutback cooling performance are investigated including three types of internal turbulators, the cutback with/without land extensions and three kinds of ejection lip profiles. The elliptic pin fins with streamwise orientation significantly improve ηaw at the rear part of the cutback surface over the baseline model with cylindrical pin fins and slightly increase Cd. However, the elliptic pin fins with spanwise orientation drastically reduce the ηaw and Cd. Downstream of the cutback, the coherent structures are strongly disturbed and become chaotic compared to the TE with cylindrical and streamwise oriented elliptic pin fins. The application of land extensions only causes an evident change to the coherent structure immediate downstream of the lip, and slightly improves ηaw and reduces Cd over the baseline model on the rear part of the cutback surface. Rounded lip shapes B and C also show an obvious increase in ηaw on the rear part of the cutback surface but only a minor increase in Cd compared to the straight lip shape A. The rounded lip helps the coolant diffuse into the TE cutback and reduce the intensity of mixing. Due to larger rounding radius of shape B, the cooling effectiveness predicted by shape B is slightly better than shape C.