Effect of vapor pressure on Marangoni condensation heat transfer

In order to study the effect of vapor pressure on Marangoni condensation process of water-ethanol mixture vapor on a vertical plate, a Marangoni condensation experimental system was founded. The condensation characteristics of pure water, water-ethanol mixture (ethanol vapor mass fraction was 2.28%, 5.1% and 51%) and pure ethanol under three pressures (31.16 kPa, 47.36 kPa, 84.53 kPa) and different surface subcooling (2-32 °C) were experimentally studied, the experimental results showed that, heat transfer coefficients of Marangoni condensation increased with vapor pressures under the same vapor velocity and vapor concentration, the reason was that, the increase of vapor pressure can induce the enhancement of the mass, the surface tension, the average temperature and the disturbance of condensate film, and hence the heat and mass transfer ratio at the condensate-vapor interface improved.