气膜抽吸与叶片前缘内部壁面射流的作用机制

The computational models of single-channel wall jet cooling with film suction are established at the leading edge of turbine blades in this paper to reveal the interference effect of film suction on the flow and heat transfer of wall jet and obtain the flow and heat transfer characteristics in the wall jet cooling channel. The RANS method with SST kω turbulence model is adopted to research the effects of film suction, jet Reynolds number, film hole position, number and other factors on the internal cooling characteristics of wall jet. The results show that film suction can significantly improve the stability of flow structures. The heat transfer coefficient near the inlet of film hole can be raised notably by the separation vortex. The decreased mass flow rate of the wall jet brought from the film suction is not conductive to the cooling of the downstream target. However, the decreasing level of flow loss at the stagnation area and channel is larger than the mixing loss in film hole, thereby reducing the overall flow loss coefficient by 4.5%. With the increase of the Reynolds number, the heat transfer intensity will improve, which, however, has little effect on the flow structure. Among the structures with a single film hole, the opening at the position of the leading edge stagnation line can provide the highest film flow ratio and has a good cooling effect on the target surface inside the leading edge. Among the structures with multiple holes, the structure with double film holes has the largest flow loss, and the structure with three film holes has the most balanced flow loss and heat transfer intensity. The research results provide a basis for the arrangement of film holes for the wall jet cooling structure, and provide a reference for further improvement of the cooling effect.