Large-Eddy Simulation of Double-Row Compound-Angle Film-Cooling: Setup and Validation

Abstract

Film cooling is an important technique allowing to increase the thermal efficiency of gas turbines. By blowing cool air through an array of small holes in the turbine blades a thin fluid film is set up shielding the blades from the hot gas arriving from the combustion chamber. This work presents a Large-Eddy Simulation of a particular film-cooling configuration known to provide a high level of effectiveness. It incorporates spanwise rows of holes which, by pairwise combination, generate a so-called anti-kidney-vortex. The simulation setup employs the Navier–Stokes code NSMB for compressible flow including the Approximate Deconvolution Model for subgrid turbulence modeling, the Synthetic-Eddy Method for turbulent inflow generation and reflection-reducing outflow boundary conditions. The setup is first validated by simulations of standard flat-plate turbulent boundary-layer flow without blowing. Results of the film-cooling simulation are then compared with related experimental data. They show reasonable agreement of the cooling effectiveness and temperature distribution, thus confirming the validity of the simulation approach which will be used in future studies of film cooling.