Film cooling predictions of simple and compound angle injection from one and two staggered rows
Typical film-cooling configurations of flat plates from one and two staggered rows of simple and compound angle injection holes are investigated using a three-dimensional finite volume method and a multiblock technique, which reduces significantly the core memory needed for the computations and gives more freedom in the generation of the grids. The computational method uses arbitrary curvilinear, body-fitted, multiblock, structured, nonstaggered grids. The turbulence is approximated by a standard k-epsilon model with wall functions. The accuracy of the code is improved by using a second-order-bounded scheme for convection terms for all equations including the k and epsilon turbulence model equations. The influence of number of rows and injection angles as well as the blowing ratio on the film cooling protection has been investigated and compared with experimental data. Comparison between predicted and experimental results indicates that the trends of the streamwise mean velocity and thermal fields are well predicted in most cases. However, the span wise-averaged film cooling effectiveness is globally underpredicted by the code, probably because of the limited capability of the turbulence model used. Good agreement is obtained between the predictions and measurements made downstream of two rows of compound angle injection.