中文摘要：

基于冲击冷却的复合冷却方法在高温部件热防护中应用广泛,冲击后的气流可通过连接孔进入下游通道,形成新的射流、旋流或气膜出流,了解连接孔内的流动特性和流量系数分布规律,对建立合理的内冷结构非常重要。建立了梯形内冷通道的简化放大模型,综合考虑射流角度、通道横流和气膜孔出流对侧壁出流孔流动特性的影响。使用直头五孔针对孔内流场进行测量,获得孔内流动结构和侧壁出流孔流量系数的变化规律。结果表明,侧壁出流孔内流动很不均匀,气流普遍在迎风面一侧形成局部高速区,出口截面存在较大低速分离区;横流对侧壁出流孔流动特性具有显著影响,随横流强度增加,下游孔分离区扩大并出现回流,流量系数迅速减小,孔出流量降低;当通道内没有横流时,射流角度变化对侧壁出流孔流动特性影响较小,而存在横流时,较大的射流角度会增加流动损失,加剧回流;气膜孔出流对侧壁出流孔流动结构和流量系没有明显影响。

英文摘要：

The compound internal cooling constructions based on impingement cooling were utilized broadly in the thermal protection of high temperature components. The air after impingement could enter other chambers as coolant supply through connected holes,which formed impingement jets,swirl flow or film cooling. Thus the understanding of flow characteristics and discharge coefficient distribution of these holes were important for the design of the internal coolant structures. An enlarged trapezoidal chamber with impingement jets,cross flow and film cooling was built up. Flow visualization was performed using a straight five-hole probe to gain the flow characteristics in the side exit holes,and the discharge coefficients of the side exit holes were also measured. Important results of the research include： The flow in the side exit holes were uneven. The air was constrained to windward wall and separation regions of low velocity flow were found in the outlet. Cross flow had significant influence on the flow structures and mass flow distribution of the side exit holes. The separation regions were enlarged and reverse flow emerged in the holes with the enhancing of cross flow,the discharge coeffecient and mass flow were decreased rapidly consequently. The impingement angle had little effect on the flow characteristics of the holes when there was no cross flow in the passage. Larger impingement angle tended to increase the flow loss and enhance reverse flow in the holes once cross flow was formed in the passage. The flow of film cooling holes has no evident influences on the flow structures and discharge coefficients of the side exit holes.