Effect of vapor velocity on Marangoni condensation heat transfer on vertical surface with temperature gradients

The effect of vapor velocity on Marangoni condensation heat transfer for water-ethanol mixture vapor on a vertical surface with temperature gradients was researched. The results showed the heat transfer coefficients increased with the increase of vapor velocities. The sensitivity of heat transfer coefficient to vapor velocity depended on the ethanol vapor concentration. At the low range of ethanol vapor concentration, the effect of vapor velocity on heat transfer coefficient was much significant. For the mixture vapor with higher ethanol vapor concentration, the effect became weak. Compared to the effect of vapor velocity on the heat transfer coefficient of solutal Marangoni condensation, the effect of vapor velocity on that of Marangoni condensation driven by temperature and concentration gradients was much weak.