摘要
对水平刻槽管壁面二元溶液升膜形成过程进行了分析。在同一热流密度下,不同升膜工质在管壁面的分布状态也不相同。由于刻槽管特殊的几何结构,液膜表面能实现欠热蒸发和过冷沸腾。实测了水平刻槽管壁面水和不同质量分数的NaCl溶液液膜内温度分布、周向换热系数和厚度分布。试验结果表明:NaCl溶液比水更易形成升膜,并且升膜的速度比水的大,所以换热效果比水的好,溶液质量分数对换热系数和温度分布存在影响。质量分数越大,溶液的换热系数也就越大,液膜内的温度变化也就越明显。对于一定质量分数的溶液,溶液的换热系数只与液膜的厚度分布有关。
Experimental investigation on rising film formation process of binary solution on the fluted helix surface of a horizontal tube was carried out. The rising film has different state distribution because of different rising film media. Due to specific geometry of the fluted helix surface, sub-cooled boiling can be realized on the interface of the rising film. The experiments were made to obtain temperature distribution in the liquid film, and circumferential film thickness and heat transfer coefficient of NaCl solution on the fluted helix surface of a horizontal tube. It is concluded that NaCl solution can form the film easier, and move quicker than water, so the heat transfer performance of the NaCl solution is better than that of water. Solution concentration has influences on both heat transfer coefficient and temperature distribution. Experiment results indicate that the heat transfer coefficient increases and temperature varies obviously with the rising of the solution concentration. For given concentration, solution heat transfer coefficient is only related to the film thickness distribution.
出处
《热科学与技术》
CAS
CSCD
2009年第3期212-219,共8页
Journal of Thermal Science and Technology
基金
自然科学基金资助项目(50676086)
S863计划资助(2008AA05208)
关键词
二元溶液升膜
水平刻槽管壁
温度场
换热系数
rising film of binary solution
fluted helix surface of a horizontal tube
temperature distribution
heat transfer coefficient
