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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.
Drop condensation has a high heat transfer rate, the condensation heat transfer coefficient is several times to several times the film-like condensation, but due to the long-term maintenance of drop condensation surface preparation technology, the technology from the industrial application of certain In the process of droplet condensation, it is often found that the droplet membrane coexists and condenses, and the heat transfer coefficient is greatly increased compared with the ordinary film-like condensation. In the past experimental studies, it is often not possible to rule out steam Organic impurities, the experimental study of the coexistence of the membrane surface also indirectly confirmed that the steam is free of organic impurities, the membrane coexistence surface is also a very practical technology to enhance condensation heat transfer, drop-shaped condensation heat transfer process is fully industrialized So it is of great theoretical and practical significance to study the characteristics of condensation heat transfer on the coexistent surface of drip film.Kumagai et al. Reported the experiment of condensation heat transfer on the coexistence surface of drip film vertically partitioned on the vertical plane.The results show that, When the area ratio of the droplet condensing zone to the film condensing zone is 1: 1, the average heat load is higher than the arithmetic average of the droplet condensation and the film condensation heat load on the usual surface, And an average heat load and the surface segmentation method and the relevant number of division. They obtained on the surface of a special form of dividing the maximum heat load is greater than when the whole surface of dropwise condensation of the maximum heat load.