Experimental and numerical investigations of vane endwall film cooling with different cooling hole configurations

In the present study, measurements are conducted to investigate endwall film cooling and its secondary effect on airfoil surfaces in a linear cascade. Validated numerical simulations are performed to obtain flow fields. Several configurations of upstream double-row cylindrical holes with an inclination angle (α) of 30 deg are studied, including streamwise holes, compound-angled holes, and double-jet film-cooling (DJFC) holes. The effects of blowing ratios ranging from 0.5 to 2.0 are also considered. Results indicate that at lower blowing ratios, strong secondary flows dominate the flow field and lead to weak coolant coverage on the endwall and the airfoil surfaces. The differences amongst the configurations are not obvious due to the insufficient coolant momentum. At higher blowing ratios, the film cooling performance on the endwall and the airfoil surfaces is greatly improved. Moreover, the effect of cooling configuration becomes more apparent as the blowing ratio increases, which determines the distribution of coolant coverage, especially on the airfoil surfaces.