Analysis of film cooling effectiveness on antivortex hole

This paper aims to mainly investigate the adiabatic film cooling effectiveness on different geometries of antivortex holes by numerical analysis. Antivortex film-cooling concept is designed to mitigate the effects of the counter-rotating vortex pair, which reduces the effectiveness of circular cross-section film-cooling holes at moderate to high blowing ratios. The 3D computational geometries are modeled with a single 30 deg angled hole on a flat surface. Numerical simulations have been performed at six different coolant-to-mainstream blowing ratios of 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0, and used five different turbulence models; k-e, RNG k-e, SSG, SST, zero equation models to obtain detailed film cooling effectiveness. The single cylindrical hole is experimentally investigated in this research to confirm the certainty of numerical results of antivortex holes. Antivortex hole shows significantly improved 2D lateral spreading and spanwise averaged film-cooling effectiveness as compared to cylindrical hole due to the anti-vortex by side holes which reduced the detrimental vorticity produced by main hole.