Study on cooling effectiveness of an afterburner heat shield with annular- type film holes

In order to enhance the local film cooling effectiveness and improve its uniformity, this paper proposes a novel annular film hole configuration, which is composed of four half arc-shaped annular holes instead of traditional cylindrical hole. Numerical simulation has been conducted to investigate the cooling characteristics of the present hole in an afterburner heat shield. As the refence, the values of cooling effectiveness of a converging round-slot film hole and a cylindrical film hole have been compared respectively. Furthermore, to validate the numerical method, the experiment measurement on the overall cooling effectiveness of a cylindrical film hole has been conducted by using an infrared thermometer. As a results, the annular holes on the afterburner heat shield behave a significant better cooling effectiveness. The optimal film cooling effectiveness of the annular hole is achieved at approximately M = 0.9. At this condition, the area-averaged film cooling effectiveness of the annular hole is 76.3% higher than that of the converging round-slot hole and 67.4% higher than that of the cylindrical hole. Additionally, the optimal overall cooling effectiveness of the annular holes in multi-row configuration is achieved at approximately M = 1.2. At this condition, the area-averaged overall cooling effectiveness of the annular holes are 7.38% greater than that of the converging round-slot hole and 21.5% greater than that of the cylindrical hole.