液氮在狭缝通道内受迫流动沸腾换热的实验研究

Experimental Studies on the Boiling Heat Transfer Performance of a Forced Liquid Nitrogen Flow in Narrow Channel

对液氮在 0 .5～ 1.5mm狭缝通道内受迫流动沸腾换热的情况进行了研究 .实验结果表明 :液氮在弦月形狭缝通道中的受迫流动沸腾换热系数是传统大直径光管池沸腾的 3～ 5倍 ;与热虹吸狭缝通道内沸腾传热相比 ,当热流密度高于 10kW /m2 时 ,受迫流动沸腾在换热温差和换热系数两方面有明显优势 ;液氮受迫流动沸腾换热系数随质量流速的增加而增加 ,随热流密度增加的趋势更为显著 ;狭缝间隙尺寸减小 ,换热效果增强 .弦月形通道与环缝通道相比 ,在相同的条件下 。

It was shown in our experiment that boiling heat transfer coefficient of forced liquid nitrogen flow in lunate channel is 3～5 times larger than that in smooth tube. The forced boiling flow in narrow channel can transfer more heat compared with thermosyphon flow in the heat flux range over 10 kW per square meters. The heat transfer coefficient shows strong dependence on heat flux and increases with increasing heat flux. But its dependence on mass flux is weak. Boiling heat transfer of nitrogen in narrow channel increases with decreasing of gap size of the narrow channel. Under the same experimental condition, boiling heat transfer of nitrogen in lunate narrow channel performs better than that in circular narrow channel.