Abstract: A simplified trapezoidal duct was built up to imitate the internal cooling cavities utilized near the leading edge. An experimental research on the impingement cooling in the trapezoidal duct was conducted to understand the flow fields in the duct and heat transfer characteristics on the target wall. The experimental data of the heat transfer was analyzed combining with that of the flow field.It is helpful to understand the heat transfer mechanism inside such a kind of confined channel. It can also provide some useful information for the design of a more effective internal cooling structure. The temperature on the target wall was measured by the thermocouples. The effects of the impingement angle, the cross flow and the impingement Reynolds number on the Nusselt number on the target wall were considered. Important results of the research include:the lower impingement jets impinge the target wall effectively, the higher impingement jets fail. The increase of the impingement angle enhances the impingement cooling of the lower impingement jets but has no effect on those at higher position. A strong cross flow severely impairs the heat transfer on the target wall, but the increase of the impingement Reynolds number improves the heat transfer ability evidently on the entire target wall. The data of the heat transfer experiment agrees well with the flow field analysis shown in the previous research. 

Key words: Leading edge; Trapezoidal duct; Impingement cooling; Cross flow; Heat transfer characteristics

摘要： 为了深入了解冲击冷却在涡轮叶片前缘的应用效果,建立了其附近梯形内冷通道的放大模型,对冲击冷却进行试验研究,测量腔内流场和壁面换热特性,在已掌握流动结构的基础上进行换热分析,更好地理解此类受限通道内冲击冷却的强化换热机理,为更高效的内冷通道设计提供参考。使用热电偶对通道靶面温度进行了详细测量,研究射流角度、横流和射流雷诺数对靶面换热努塞尔数的影响规律。结果表明:较低位置射流对靶面具有较强的冲击作用,而较高位置射流未对靶面形成冲击；射流入射角度的增加会提高较低位置射流在靶面上的冲击换热能力,对较高位置射流的换热没有明显影响；较强的横流将严重削弱靶面冲击区的换热能力,射流雷诺数的增加将大幅提高整个靶面上的换热能力；换热试验结果与前期研究的流场分析结论非常一致。 

关键词: 前缘;梯形腔;冲击冷却;横流;换热特性 