Experimental Study on Condensation Heat Transfer of Ethanol–Water Vapor Mixtures on Vertical Micro-tubes
Experimental Study on Condensation Heat Transfer of Ethanol–Water Vapor Mixtures on Vertical Micro-tubes
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DOI：
10.1007/s10765-015-1898-z
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发表时间：
2015-05
影响因子：
2.2
通讯作者：
Xiping Chen;Jinshi Wang;Junchao Qin;D. Chong;R. Huang;Junjie Yan
中科院分区：
文献类型：
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作者：
Xiping Chen;Jinshi Wang;Junchao Qin;D. Chong;R. Huang;Junjie Yan
本文对乙醇-水蒸汽混合物在外径为0.793mm、1.032mm和1.221mm的垂直微管束上的Marangoni凝结换热进行了实验研究。实验进行了广泛的乙醇质量分数的蒸汽混合物中不同的蒸汽速度和压力。凝结换热系数随汽壁温差的增大呈现先增大后减小的非线性特性。在相同实验条件下，水蒸气中乙醇质量分数为2%时的凝结换热系数最高。在低乙醇质量分数下，乙醇-水蒸汽混合物的冷凝传热系数是纯蒸汽的2 ~ 3倍。蒸汽压和速度对冷凝传热的影响表明，对于不同乙醇质量分数的所有蒸汽混合物，每个微管上的冷凝传热都呈正趋势。结果表明，直径为1.032 mm的微管束上的冷凝换热系数高于其他两种微管束上的冷凝换热系数，存在一个临界直径，该临界直径下的冷凝换热系数最大。
The paper presents an experimental investigation of Marangoni condensation heat transfer of ethanol–water vapor mixtures on vertical micro-tubes with an outer diameter of 0.793 mm, 1.032 mm, and 1.221 mm. Experiments were performed over a wide range of ethanol mass fractions in vapor mixtures for different vapor velocities and pressures. Condensation heat transfer coefficients behaved nonlinear characteristics, increased, and then decreased with increasing vapor-to-surface temperature difference. Under the same experimental conditions, the condensation heat transfer coefficient at a 2 % ethanol mass fraction in vapor was the highest. At low ethanol mass fractions, the condensation heat transfer coefficient of the ethanol–water vapor mixture was 2 to 3 times greater than that for pure steam. The effect of vapor pressure and velocity on condensation heat transfer suggested a positive tendency on each micro-tube for all vapor mixtures with different ethanol mass fraction. Results showed that condensation heat transfer coefficients on micro-tubes with a diameter of 1.032 mm were higher than those on the other two micro-tubes, suggesting that there existed a critical diameter which gave the largest condensation heat transfer coefficient.