摘要
本文对水和酒精混合蒸气在表面具有不均匀温度场的竖直平板上的凝结换热进行了实验研究,分别从凝结换热特性和凝结形态两个方面与具有均匀温度场的竖直平板凝结换热实验结果展开了比较。实验结果表明,本实验凝结面上的液珠明显要比均匀温度场的密集细小,液珠的冲刷速度也明显较快;在相同的工况下,本实验中的凝结换热系数在任何浓度下都比均匀温度场壁面的高。初步的理论分析也表明,本实验中凝结表面浓度梯度和温度梯度共同作用引起表面张力梯度增大,导致的Marangoni对流加强,凝结换热得到强化。
Marangoni condensation heat transfer characteristics for water-ethanol mixture vapor on a vertical surface with temperature gradients were studied experimentally. The present heat transfer coefficients and condensation modes were compared with those on a flat vertical surface with uniform temperature, respectively. The comparison showed that, the present condensation drops tended to be denser and tinier and the sweep speed of drops was faster. Under the same condition, the present heat transfer coefficients were higher than those on the flat surface for frill ethanol concentration range. The preliminary analysis also shows that, under the coaction of concentration and temperature gradients, the surface tension gradients on the condensate surface become greater, leading to the Marangoni condensation heat transfer to be further enhanced.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2008年第10期1703-1706,共4页
Journal of Engineering Thermophysics
基金
国家自然科学基金(No．50476048；No．50521604)
关键词
MARANGONI凝结
温度梯度
换热系数
marangoni condensation
temperature gradient
heat transfer coefficient
