小空间内冲击/气膜复合冷却换热特性试验

利用相似理论的原理, 试验研究了封闭小空间内冲击/气膜复合冷却内表面的换热特性.研究中通过改变冲击Re数（1000040000）、冲击距离H和冲击孔直径D之比H/D（0.172.0）, 在2种冲击孔和气膜孔间距P和冲击孔直径D之比P/D（0, 1）条件下, 细致分析冲击Re数、H/D对复合冷却内表面局部换热特性的影响.结果表明, 在本文的试验工况中, 冲击靶板上的局部Nu数随着冲击Re的增加而不断变大, 而Nu数随着H/D的变化规律并非单调.当P/D=0, H/D=2时换热效果达到最佳;P/D=1时, 在X/D=±3范围内, 小冲击Re数条件下H/D=0.17和H/D=2的换热效果比较接近, 大冲击Re数条件下H/D=1和H/D=2的换热效果比较接近. 

Experimental investigation of the local heat transfer of impinging cooling with outflow film in closed small space

Experiments were carried out to investigate the heat transfer of compound cooling(impinging cooling with outflow film).Local heat transfer coefficients on inner surface were obtained over a Reynolds number range of 10 000~40 000,nozzle-to-plate spacing H/D range of 0.17~2.0,the ratio between impinging jet and film hole distance to jet hole diameter P/D range of 0 and 1.Experimental results show that the local heat transfer coefficient was affected by impingement Reynolds number and nozzle-to-plate spacing greatly.Under the parameters in this paper,the local Nu number increased with the impingement Reynolds number.When P/D=0,the maximum Nu number was achieved while H/D=2.When P/D increased to unity,the maximum Nu number was gotten while H/D=2 and 0.17 under lower impingement Reynolds number.And this proper value of H/D will change to be 2 and 1 under higher impingement Reynolds number.