Assessment of the Turbulence Characteristics of Shaped Film Cooling Hole with Scale Resolving Simulation

The turbulence characteristics of the shaped hole film cooling are very complex. In this study, Large Eddy Simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) are used to study the film cooling of the shaped hole. The time-averaged results are compared with the experimental data in the literature. Because of the eddy-viscosity model, the RANS method roughly deals with the simulation of boundary layer, which leads to a large deviation. The RANS results are compared with the LES results to identify the weaknesses of the Realizable k-ε model in predicting the turbulence characteristics of the shaped hole film cooling. The eddy viscosity hypothesis and the temperature gradient diffusion hypothesis are evaluated using LES data. Furthermore, the turbulence characteristics of the in-hole flow are analysed with the help of the incremental Proper Orthogonal Decomposition (iPOD). The turbulence presents strong anisotropy and some convection structures are induced from the shear zone.