射流冲击对内冷通道侧壁面换热特性影响研究

Investigation on Effects of Impingement Jets on Heat Transfer Characteristics of Internal Cooling Passage Side Wall

关键词:  前缘  内冷通道  冲击冷却  横流  换热特性

Key words:  Leading edge  Internal cooling passage  Impingement cooling  Cross flow  Heat transfer characteristics

摘要:

建立了前缘梯形内冷通道的放大模型，结合斜射流冲击冷却进行试验测量，研究通道内壁面的换热特性，并结合流场测量结果进行换热分析，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。使用热电偶对出流侧壁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其Nu的影响规律。结果表明:出流孔的抽吸作用会强化孔排上方和下方边缘附近壁面的换热；射流入射角度的增加使出流孔上方壁面的Nu峰值对横流强度变化的敏感度提高；横流会削弱侧壁面上Nu峰值，且对出流侧壁面的不同区域换热情况的影响位置不同；射流雷诺数的增加将大幅提高整个出流侧壁面的换热能力，但对其换热特性规律不会产生影响。

Abstract:

A simplified enlarged model of the trapezoidal internal cooling passage near the leading edge is built up. An experimental research based on the inclined impingement cooling in the passage is conducted to understand the heat transfer characteristics on the internal wall. The data of the heat transfer is analyzed combining with the flow fields data，which is helpful to understand the heat transfer mechanism inside such kind of confined channel as well as provide some useful information for the design of a more effective internal cooling structure. The temperature on the side exit wall was measured by the thermocouples. The effects of the impingement angle，the cross flow and the impingement Reynolds number on the Nusselt number of the side wall were considered. Important results of the research include: the suction effect of the side exit hole enhances the heat transfer of the side wall near the hole edge. The increase of the impingement angle makes the peak of Nu become sensitive to the variation of the impingement angle. The cross flow decreases Nu on the side wall and has different effects on the different region of the side wall. The increase of the impingement Reynolds number improves the heat transfer ability evidently on the entire side wall，when it does not change the heat transfer characteristics on the side wall.