COMPARISON STUDY OF CLOSURE MODELS FOR MODELLING A FLOW ON CURVED AND FLAT PLATES. FILM COOLING APPLIED TO GAS TURBINE BLADE

摘要

A numerical study of the interaction of a row of jets of a secondary coolant fluid (R<1) in transverse flow is performed. Discrete jets are arranged across a surface exposed to a wall boundary layer of parallel compressible stream (M_∞=0,72), as occurs in certain discrete-hole cooling systems for turbine blades. The simulation is performed by solving the governing equations numerically, with the effects of turbulence modeled in a way which allows for the anisotropies existing in the real situation and the effects of stream curvature. Comparisons between the results of three turbulence models obtained for injection angle of 45 deg and blowing rate less than unity show discrepancies observed in the flow near the wall. The causes of these differences are identified and discussed.