高压涡轮机匣加强肋表面换热特性试验

针对高压涡轮叶尖间隙主动控制机匣的多层结构,重点分析了机匣内部加强肋和安装螺栓共同组成的基本换热单元,利用热膜法研究了加强肋表面的局部和平均传热系数,得到了不同进气状态、加强肋高度对传热系数的影响规律。研究发现:冲击靶面传热系数随着冲击雷诺数的增长而增大,但传热系数的增长速率随着冲击雷诺数的增大而缓慢降低。3排冲击射流工况中,靠近出流位置的加强肋表面平均传热系数最高。试验结果表明,加强肋表面的传热系数受到加强肋高度和冲击雷诺数耦合作用。在高雷诺数时,增加加强肋高度带来的换热强化效果更加明显。 

Experiment on surface heat transfer characteristic of high rib in high pressure turbine casing

Abstract:According to the multilayer high pressure turbine case applied in an active clearance control system, a typical compound cooling structure consisting of impingement with high ribs and embedded bolts was investigated. The effects of jet Reynolds number, the ratio of height of rib to jet holes diameter on local and average heat transfer coefficients were experimentally studied. It was found that the heat transfer coefficients of target surface were improved with the increase of jet Reynolds number, while the growth rate slowed down. The highest average heat transfer coefficient was observed at the region near the exhaust channel when three rows of jet holes were used. The experimental results showed that the heat transfer coefficients on high rib surfaces were influenced by both the height of rib and impinging Reynolds number. Increasing the height of rib led to higher heat transfer coefficients, and this trend becomed more distinguished in large Reynolds cases.