CIESC Journal

• 化工学报 • 上一篇    下一篇

滴膜共存表面强化冷凝传热

马学虎,徐敦颀,林纪方,王补宣   

  1. 大连理工大学化学工程系!大连116012,大连理工大学化学工程系!大连116012,大连理工大学化学工程系!大连116012,清华大学热能工程系!北京100084
  • 出版日期:1999-08-25 发布日期:1999-08-25

CONDENSATION HEAT TRANSFER ENHANCEMENT WITH DROPWISE AND FILM COEXISTING CONDENSATION SURFACES

Ma Xuehu, Xu Dunqi and Lin Jifang ( Department of Chemical Engineering, Dalian University of Technology, Dalian 116012)Wang Buxuan( Department of Thermal Engineering,Tsinghua University, Beijing 100084)   

  • Online:1999-08-25 Published:1999-08-25

摘要: <正>滴状冷凝具有很高的传热速率,其冷凝传热系数是膜状冷凝的几倍至几十倍,但是,由于长期维持滴状冷凝表面制备技术的限制,该技术距工业化应用还有一定的距离,在滴状冷凝的研究过程中,经常发现滴膜共存冷凝现象,而且传热系数较普通的膜状冷凝有较大的提高,在以往的实验研究中,往往不能肯定地排除蒸汽中有机杂质的影响,滴膜共存表面的实验研究也间接地证实了蒸汽中是不含有机杂质的,滴膜共存表面也是强化冷凝传热很实用的技术,是滴状冷凝传热过程全面工业化的过渡阶段.所以,研究滴膜共存表面强化冷凝传热的特性具有重要的理论意义和实用价值.Kumagai等报道了在竖平面上垂直分割的滴膜共存表面上冷凝传热的实验.结果表明,当滴状冷凝区和膜状冷凝区的面积比为1:1时,平均热负荷要高于在通常表面上滴状冷凝和膜状冷凝热负荷的算术平均值,而且平均热负荷与表面分割方式和分割数目有关.他们在一种特殊分割形式的表面上得到的最大热负荷高于当全部表面为滴状冷凝时的最大热负荷.

Abstract: With six surfaces prepared for different surface division patterns, steam condensation heat transfer characteristics on dropwise and film coexisting surfaces were investigated experimentally under atmospheric pressure. Dropwise condensation was promoted with ultrathin polytetrafluoroethylene (FIFE) film, which was prepared by the dynamic ion-beam mixed implantation (DIMI) method. It was found that the condensation phenomena at the interconnecting section between dropwise and film condensation parts were quite different for the different relative position of dropwise and film condensation parts. Experimental results revealed that condensation heat transfer characteristics were greatly influenced by the surface division pattern and the relative area ratio of dropwise and film condensation parts. The enhancement mechanism of condensation heat transfer was discussed accordingly.

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