Numerical investigation on flow and heat transfer characteristics of vortex cooling in an actual film-cooled leading edge

Abstract

This paper numerically investigates the flow and heat transfer characteristics of vortex cooling in an actual film-cooled leading edge. Two internal vortex cooling cases called Case P and Case S are involved in this study. Case P means that the coolant injection nozzles are arranged near the pressure surface side of the blade, and Case S means that the coolant injection nozzles are arranged near the suction surface side. The mainstream region and the swirl chambers of the vortex cooling cases are connected by 6 rows of film holes. Results indicate that the practical mainstream flow generated by the actual blade affects the vortex flow structures and brings about an endwall secondary flow. For internal vortex cooling, the large-scale vortex flow structures in Case P skew off while flow structures in Case S are not distinctly influenced. Two type of flow regimes form near the film hole due to the suction effect, and bring about different local heat transfer augmentation intensity. For film cooling, the endwall secondary flow forces the coolant film move towards or away from the endwall thus decreases the film cooling efficiency. The film hole blowing ratio distribution is affected due to the different influence of mainstream flow on internal vortex flow of Case P and Case S, which results in different film cooling efficiency distribution. The film cooling efficiency of Case S on the pressure surface increases by up to 59.8% compared with Case P.