Effect of vapor velocity on Marangoni condensation heat transfer for water-ethanol binary vapor mixture

Reported herein are the experimental data for so-called Marangoni condensation of steam-ethanol on small vertical plane surfaces at the vapor pressure of 47.36 kPa. In order to clarify the effect of vapor velocity on Marangoni condensation, heat flux and vapor-to-surface temperature difference were measured for steam-ethanol mixtures over a wide range of composition at vapor velocity of 2, 4 and 5 m/s. The experimental results showed that heat transfer coefficients of mixture vapors with different composition increased with vapor velocity, and the effect of vapor velocity in enhancing the condensation heat transfer coefficient was less for pure steam or extremely low or high composition of 0.5% and 50% than for middle composition of 2%.