Film-Cooling Prediction on Turbine Blade Tip with Various Film Hole Configurations

Abstract

Different film hole arrangements on the plane and squealer tips of a turbine blade are investigated using a Reynolds stress turbulence model and nonequilibrium wall function. The three film hole configurations considered are 1) the camber arrangement, where the film-cooling holes are located on the mid-camber line of the tips; 2) the upstream arrangement, where the film holes are located upstream of the tip leakage flow and high heat transfer region; and 3) the two-rows arrangement, which is a combination of the camber and upstream arrangements. Calculations were performed first for the nonrotating cases under low inlet/outlet pressure ratio conditions with three different blowing ratios. The predicted heat transfer coefficients are in good agreement with the experimental data, but the film-cooling effectiveness is somewhat overpredicted downstream of the film holes. Simulations were then performed for the nonrotating and rotating camber line film hole configuration under high inlet/outlet pressure ratio conditions, which are close to engine conditions. It is found that the rotation decreases the plane tip film-cooling effectiveness but only slightly affects the squealer tip film cooling. However, the rotation significantly increases heat transfer coefficient on the shrouds.