Study of marangoni condensation characteristics on non-isothermal surfaces

Experimental tests were performed on Marangoni condensation heat transfer of ethanol-water mixtures with different concentrations on a surface with temperature gradient. Results indicate that for the mixture with a mass concentration of 1% ethanol and 99% water, the heat transfer coefficient can be raised by 15%, under same experimental conditions (p = 84.5 kPa, v = 2 m/s), compared with that of Utaka experiment. Under similar experimental conditions, the improvement of heat transfer coefficient of test block with temperature gradient is found to be caused by existence of two reverse motions in the condensation film, which disturbs the condensation film and hence reduces its heat resistance. Moreover, qualitative analysis is also carried out to study how the heat transfer coefficient varies with the degree of supercooling.