Film Cooling is a crucial technology for engine manufacturer to develop high-efficiency gas turbine engines by raising turbine entry temperature. A lot of cooling holes geometries have been studied in the past few years in tests, as well as numerical simulations. Shaped holes are nowadays a standard geometry for protecting the blades, given the performance improvement compared to cylindrical holes. Numerical correlation with physical tests is challenging due to the high sensitivity to thermal mixing and adequate boundary condition predictions.
This paper is devoted to numerical simulation comparisons of the 777 shaped holes configuration of Pennsylvania State University, for an incompressible flow with a density ratio of 1.5, a blowing ratio of 1.5 and a free stream turbulence intensity of 0.5%. Two different simulations have been chosen: a state-of-the-art RANS simulation with k-e Realizable model computed with ANSYS Fluent and a high fidelity solver Lattice-Boltzmann Method computed with Simulia PowerFLOW.
In order to improve the accuracy of numerical simulations against test results, this article deals with an aerothermal model of the complete test bench. This additional modeling allows to strongly improve thermal prediction and to understand initial discrepancies related to test bench environment.
Results show that k-ε Realizable simulation provides a good prediction of average effectiveness, but local differences appear due to inherent RANS modeling limitations. On the other hand, LBM simulation provides excellent results for both aerodynamic and thermal quantities: tests results are very well reproduced.