Experiments were conducted to measure condensation heat transfer of steam-ethanol mixtures on a horizontal smooth tube. Heat flux and vapor-to-surface temperature difference were accurately measured over a wide range of mass concentration of ethanol (0.001%, 0.005%, 0.01%, 0.025%, 0.05%, 0.1%, 0.5% and 1.0%.) at atmospheric pressure. The present work extends earlier data of Murase et al. (2007) and Ali et al. (2013) to lower mass concentration of ethanol and higher vapor-to-surface temperature difference. Visual observations, the appearance of condensate, show the condensation modes and their transitions of pseudo-dropwise, rivulets and filmwise. Heat flux and heat-transfer coefficient are found to increase, reach to a peak and decrease as vapor-to-surface temperature difference increases for all mass concentrations of ethanol and vapor velocities. The maximum heat-transfer coefficients appear in the range of mass concentration of ethanol from 0.01% to 0.025%. The highest heat-transfer coefficient values are 112.4 kW/m² K and 93.9 kW/m² K at ΔT = 3.43 K and 4.46 K, respectively. The maximum enhancement ratio of 5.5 is achieved at vapor-to-surface temperature difference of 4 K and mass concentration of ethanol 0.01%. The results also show that heat-transfer coefficient of filmwise eventually approaches to a value slightly higher than that of pure steam.

进行实验以测量水平光滑管上蒸汽-乙醇混合物的冷凝传热。在大气质量浓度范围内（0.001%、0.005%、0.01%、0.025%、0.05%、0.1%、0.5% 和 1.0%），准确测量了热通量和蒸汽-表面温度差。压力。目前的工作扩展了 Murase 等人的早期数据。(2007) 和 Ali 等人。(2013) 以降低乙醇的质量浓度和更高的蒸汽与地表温差。目视观察，冷凝物的出现，显示了冷凝模式及其伪滴状、小溪状和薄膜状的转变。发现热通量和传热系数随着乙醇和蒸汽速度的所有质量浓度的蒸汽与表面温差的增加而增加，达到峰值并降低。最大传热系数出现在乙醇质量浓度从 0.01% 到 0.025% 的范围内。最高传热系数值为 112.4 kW/mΔ T  = 3.43 K 和 4.46 K 时分别为² K 和 93.9 kW/m ² K。在 4 K 的蒸汽与表面温差和 0.01% 的乙醇质量浓度下实现了 5.5 的最大增强率。结果还表明，薄膜的传热系数最终接近于略高于纯蒸汽的值。