中文摘要：

在蒸气流速4m·s^-1的条件下，通过实验研究了不同蒸气压力下纯水、纯酒精和不同酒精浓度水-酒精混合蒸气沿重力方向流过竖直铜平板表面上的凝结换热特性，并实现了实验的可视化，同时从理论上初步分析了混合蒸气压力对Marangoni凝结换热特性的影响．实验及理论分析结果表明，在相同蒸气浓度、蒸气流速和表面过冷度条件下，高压下的凝结换热强度比低压的大．且蒸气压力对凝结换热的影响因混合蒸气酒精浓度的不同而不同，在低浓度1％、2．28％和高浓度22％、51％时压力的增加对凝结换热特性的影响较小，而在中间浓度5．1％和9．8％时凝结换热系数随压力的增加明显．

英文摘要：

When a water-ethanol binary mixture vapor condenses on a vertical flat plate, the condensate film rises locally and creats many drops on the film. Many researchers called such a phenomenon non-film condensation, pseudo-dropwise condensation or Marangoni condensation. The purpose of this paper was to experimentally study the effect of vapor pressure on Marangoni condensation. At the same vapor speed u= 4 m·s^-1 and three different vapor pressures, i.e. , 31.16 kPa, 47.36 kPa and 84.53 kPa respectively, the condensation processes of the vapors of water, ethanol and water-ethanol mixture on a brass block were studied and the variation of condensation mode was observed. The results showed that, at the same vapor concentration/speed and surface subcooling, the heat transfer coefficients of high vapor pressure were larger than those of low vapor pressure. Furthermore, at different concentrations, the vapor pressure had different effects on condensation. For water-ethanol mixture vapors of extremely high or low concentration of 22%, 51%, and 0.5%, 1%, the vapor pressure had little effect on the condensation heat transfer, but for mixture vapors of 5.1% and 9.83 %, heat transfer coefficients increased obviously with the vapor pressure.