FC-72在竖直壁面上及微小三角型通道内的沸腾传热

本文对浸在FC-72液池中的竖直壁面及两个微小三角形通道进行了沸腾实验研究,考虑了管道尺寸对沸腾传热特性的影响。两个微小三角形通道的边长分别为1.5和2.5 mm,水力直径分别为0.87和1.44 mm,长度50 mm,采用铜块上开V型沟槽,再覆盖上透明的玻璃片构成。热流密度由贴在铜块背后的膜状加热器提供。实验得到了沸腾曲线和传热系数,并用DV摄影机拍摄到了沸腾状况。实验结果显示,管道尺寸对沸腾传热特性有显著的影响,CHF值随通道尺寸的减小而减小,小通道在低热流密度时传热系数较大。

BOILING HEAT TRANSFER OF FC-72 ON A VERTICAL SURFACE AND INSIDE MINIATURE TRIANGULAR CHANNELS

Boiling heat transfer of FC-72 on vertical surface and inside miniature triangular channels was experimentally studied. The triangular test section was formed by grooving the flat surface into a V-shaped channel and covered by a transparent glass plate. The hydraulic diameters the triangular channels are 0.87 and 1.44 mm respectively. Boiling curves and heat transfer coeflicients were obtained experimentally. The boiling behaviors on vertical surface and inside triangular channels were visualized with a digital video camera. Experimental results show that the tube geometry has a significant effect on the boiling characteristics. The CHF decreased with the reduction of channel size, and the heat transfer coefficient for the smaller triangular channel is better at small heat flux. The boiling curves further demonstrate that both the CHF and the heat transfer rate for the triangular channel are higher than those for a circular tube having the similar diameters.