Numerical investigation of film cooling with anisotropic turbulence model

An in-house three-dimensional Navier-Stokes code was developed to evaluate numerically the advantages of the anisotropic turbulence model over the classical isotropic k-ε model in a typical film cooling experiment.The anisotropic turbulence model was the k-w turbulence model incorporated with anisotropic coefficient.The effects of the anisotropic turbulent transport coefficient on the flow and temperature filed were analyzed in detail.The applicability of this model was also discussed.Comparison result reveals that the introduction of the anisotropic turbulent transport coefficient intensified the turbulent mixing of cooling jet with the main stream in lateral direction,and subsequently enhanced the lateral spreading of cooling air.The cooling effectiveness in centerline predicted by the anisotropic model was much closer to experimental data than that by the standard k-ε model.The anisotropic model was in good agreement with the experimental results at low-mass flux ratio condition(M=0.5).However,with the increase of mass flux ratio,the jets tend to be detached and then reattached to the wall,the discrepancy upstream the reattachment increased due to the limitation of the anisotropic coefficient,and downstream the reattachment these two agreed well consistently.