半封闭通道射流冲击换热特性的实验

运用红外热像仪测试技术对半封闭通道单、双排孔射流冲击冷却进行了热像显示试验,总结了各种流动参数和几何参数对局部换热特性的影响规律:对于单排垂直射流,冲击冷却效果随冲击雷诺数的增加、孔间距与直径比的减小而得到提高,冲击间距比为2时换热效果最好;冲击孔中心线向通道封闭一侧倾斜后,射流冲击冷却的范围变窄,当冲击间距比大于2时驻点区的对流换热能力明显降低;对于双排冲击射流,在较小的冲击射流雷诺数和较大的冲击间距比下,后排射流的冲击换热效果要逊于前排射流.

Convective heat transfer of jet impingement inside semi-confined channel

The thermal image visualization of jet impingement cooling with single or double rows of holes inside the semi-enclosed channel were revealed by using infrared camera and then the impingement cooling heat transfer coefficients were deduced.The effects of flow and geometric parameters on convective heat transfer coefficients were obtained.The results show that: for a single row normal impingement,the impingement cooling effectiveness is enhanced with the increase of impinging Reynolds number or the decrease of hole spacing to diameter ratio,and the best effectiveness is achieved under the jet-to-surface spacing equals to 2;when the jet is oblique to the confined wall,the cooling effectiveness is weakened especially when the jet-to-surface spacing ratio is greater than 2;for double rows of holes with normal impingement cooling,the cooling effectiveness of rear row jets is weaker than the front row jets at lower impinging Reynolds number or larger jet-to-surface spacing.