Numerical study of the effect of internal coolant crossflow on film cooling effectiveness

This paper investigated numerically the effect of a coolant crossflow on film cooling effectiveness. Computations were performed to investigate the three-dimensional film cooling flow and cooling effectiveness with two crossflow ratios (Cr=0.39, 0.78) and two blowing ratios (Br=1, 2) and two length to diameter ratios (l/d=4, 8). The results of the present investigation show that there is a profound effect of how the coolant is supplied to the hole on the film-cooling performance in the near hole region, for example, crossflow ratio has great influence on the film-cooling effectiveness of surface, a bigger length to diameter ratio brings about regular flow within film holes, and a bigger blowing ratio leads to poorer adhesion of jet stream and lower film-cooling effectiveness. Therefore, crossflow at the hole entry side has to be taken into account when modeling film-cooling schemes of turbine blades.