Research of the condensation heat transfer for ethanol-water vapor on a vertical tube under different vapor pressure

This article experimentally studied Marangoni condensation characteristics of ethanol-water vapor on a vertical tube at different pressures, and observed the variation of condensation condition. The experimental results demonstrate that on the same condition of vapor concentration and speed, heat transfer coefficients of high pressure are bigger than those of low pressure in the low-ethanol concentration range. But the effect of vapor pressure on the heat transfer coefficients is not obvious in the high-ethanol concentration range. The reason for this is that bigger diffusion resistance and the gradient of the surface tension versus the condensate mass fraction becomes smaller with the increase in vapor concentration.