【摘要】 本文首先构造了一个在常温水冷却时,纯水蒸汽凝结时表面温度差可以达到11℃的黄铜试件。利用该试件在蒸汽流速为0.3m/s时,进行了不同浓度水-酒精混合蒸汽以及纯水蒸汽的凝结换热特性和凝结状态的实验研究。实验结果表明:由于凝结表面存在温度差,水-酒精混合蒸汽出现珠状凝结,凝结换热系数最大可以达到纯水蒸汽凝结的2.8倍;混合蒸汽凝结换热系数随表面过冷度减小而增加,并在较小过冷度时出现陡增;凝结换热量随表面过冷度增加存在最大值;观察得出了不同表面过冷度下不同酒精浓度时的凝结状态。更多还原

【Abstract】 A brass block whose maximal temperature difference of surface is 11℃ is constructed as an experiment element to study the condensation heat transfer. Regulations and modes of Marangoni condensation of different thickness of mixture are studied on the surface of the block when the speed of vapor is 0.3 m/s. Experiment shows hat the Marangoni condensation of mixture appears because of the distribution of the temperature and the maximal heat transfer coefficient can be 2.8 times as that of pure steam; the heat transfer coefficient of Marangoni condensation of mixture increases as surface subcooling decreases and increases rapidly when the surface subcooling is rather small; the heat transfer condensation quantity has a maximal value as the surface subcooling increases; and the different modes of condensation are also shown when the surface subcooling changes.更多还原