Overall effectiveness of film-cooled leading edge model with normal and tangential impinging jets

Abstract

Abstract This paper investigates the overall effectiveness of film-cooled leading edge model with normal and tangential impinging jets. The leading edge has three rows of cylindrical film cooling holes, located at the stagnation line (0°) and\u202f±\u202f40° measured from the stagnation line. Film cooling holes are at an inclined angle of 25° relatives to the surface. The normal jet has one row of normal jet impinging holes and the tangential jet has two rows of tangential jet impinging holes. Mainstream Reynolds number based on the leading edge cylinder external diameter is about 100,000, and the mainstream turbulence intensity is about 7%. Three blowing ratios of 0.77, 1.54, and 2.31 are considered. Pressure sensitive paint technique is applied to measure the adiabatic effectiveness with the density ratio of 0.97. Liquid crystal technique is used to obtain the overall effectiveness with the density ratio of 0.94. Numerical simulations using realizable k-ɛ (RKE) turbulence model with enhanced wall treatment were applied to calculate the adiabatic effectiveness and overall effectiveness. Compared with experiments, numerical simulations overpredict overall effectiveness about 20% to 30% between the 0° row and the 40° row, and the difference between simulations and experiments is about 10% to 20% after the 40° row. The results provide baseline information for turbine blade leading edge film cooling design and heat transfer analysis.