冲击式凹槽叶尖流动换热特性

针对冲击式凹槽叶尖的流动换热特性，采用数值模拟方法，详细分析了三种冲击式凹槽结构和三种凹槽助肋结构的间隙泄漏流场、叶尖二次流损失、叶尖总压损失系数和叶尖表面传热系数，同时考虑了助肋位置、数量和凹槽深度的影响。结果表明:叶尖凹槽前缘助肋抑制了间隙泄漏涡吸力侧分支，增强了泄漏流在凹槽内的分离流动。同一凹槽深度，双助肋凹槽叶尖的相对总压损失最小，研究范围内减小约13%。冲击式凹槽叶尖增强了泄漏流在凹槽内的掺混流动，减小了泄漏流的动能。同一凹槽深度，冲击式双助肋凹槽叶尖的相对总压损失最小，研究范围内减小约18%。冲击式凹槽叶尖减小了泄漏流在凹槽底面的再附，增大了泄漏流在叶尖突肩壁面的再附，突肩壁面出现高传热系数区域。 

Investigation on flow and heat transfer characteristics of impulse squealer tip

In order to study the aerothermal performance of impulse squealer tip, three impulse squealer and three assisted rib squealer configurations were investigated using numerical simulation method. The gap leakage flow field, tip secondary flow loss, tip total pressure loss and heat transfer coefficient were discussed in detail. The results showed that the squealer leading edge ribs suppressed the suction side branch of over tip leakage vortex, enhanced the over tip leakage flow separation in the squealer. With the same squealer depth, the relative total pressure loss of the double-ribbed squealer tips was the smallest, and the maximum decrease was up to 13% within the research range. The impulse squealer tip enhanced the leakage flow mixing in the squealer, reduced the kinetic energy of the leakage flow. With the same squealer depth, the relative total pressure loss of the impulse double-ribbed squealer tip was the smallest, and the maximum decrease was up to 18% within the research range. The impulse squealer tip reduced the leakage flow re-attachment on the cavity floor, increased the leakage flow re-attachment on the rim and rib surface of the squealer, and a high heat transfer coefficient area appeared on the rim and rib surface.