蒸气在铜表面冷凝的可视化实验

发布时间：2018-03-19 12:44

本文选题：地面重力　切入点：冷凝　出处：《空间科学学报》2016年04期 　论文类型：期刊论文

【摘要】：通过建立蒸气冷凝过程的可视化实验装置,在地面重力条件下对蒸气在铜表面的冷凝情况进行实验.采用高速摄像仪对蒸气在铜表面上发生的冷凝过程进行观测,并对比分析了H_2O,R141b以及FC-72蒸气的冷凝情况.研究发现水蒸气在冷凝过程中一些大液滴在合并周围小液滴后会发生回弹现象,从而清理掉周边区域的小液滴.随着冷凝的进行,被清理掉小液滴的区域又会重新生成小液滴.这种回弹现象相当于延长了滴状冷凝的时间,从而起到强化冷凝换热效果.R141b及FC-72在光滑铜表面上均未发生滴状冷凝.在加大过冷度后,冷凝器内残留的空气还会在冷凝液膜上冷凝成小水滴,产生滴膜共存现象.水蒸气在铜表面冷凝过程中,滴状冷凝转换成膜状冷凝后热流量降低约20%,因此需要对铜表面进行改性处理,降低其表面能,从而强化冷凝换热.
[Abstract]:By setting up a visualized experimental device for vapor condensation process, the condensation of vapor on copper surface was tested under ground gravity condition, and the condensation process of vapor on copper surface was observed by high speed camera. The condensation of H2OR141b and FC-72 vapor is compared and analyzed. It is found that some large droplets in the condensation process will rebound after merging the surrounding small droplets, thus clearing out the small droplets in the surrounding area. The area where the droplets are cleaned up will regenerate the droplets. This springback is tantamount to prolonging the condensation time of the droplets. Thus, no droplet condensation occurred on the smooth copper surface. After increasing the supercooling degree, the residual air in the condenser would be condensed into small water droplets on the condensate film. In the process of condensation of water vapor on copper surface, the heat flux decreases by about 20% after the condensation of water vapor into film, so it is necessary to modify the surface of copper to reduce its surface energy so as to strengthen the condensation heat transfer.
【作者单位】：东南大学能源与环境学院;
【基金】：载人航天工程空间应用系统天舟一号货运飞船科学实验项目资助(TZYY08001)
【分类号】：V524

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