Film Cooling on a Modern HP Turbine Blade: Part II — Compound-Angle Round Holes

A well-tested computational methodology and a companion experimental study are used to analyze the physics of compound-angle, cylindrical-hole film cooling on the pressure and suction surfaces of a modern high-pressure turbine airfoil. A single-passage cascade (SPC) is used to model the blade passage flow experimentally and computationally. Realistic engine conditions, including transonic flow, high turbulence levels, and a nominal density ratio of 1.52, are used to examine blowing ratios of 1.0, 1.5, and 2.0 on the suction surface (SS) and 1.5, 3.0, and 4.5 on the pressure surface (PS). The predicted results agree with experimental trends, and differences are explained in terms of known deficiencies in the turbulence treatment. The mean-flow physics downstream of coolant injection are influenced primarily by a single dominant vortex that entrains coolant and mainstream fluid, and by the effect of convex (SS) or concave (PS) curvature on the coolant jet.