The experiment was conducted to investigate the characteristic of capillary evaporation in capillary tubes with three different diameters using alcohol as working fluid. The results indicated that the evaporating interface with extend and form a thin liquid film during the evaporation

which can rapidly increase the evaporating rate. The temperature caused by the liquid film evaporation will change into the difference of surface tension because of the Marangoni effect

the liquid film will be supplemented while evaporating and form the high-effective “evaporation-supplement” mechanism. With the increase of the diameter

the liquid film become thicker and the stability is improved

the change rate of the interface moving rate decreased. Meanwhile

the overall evaporation rate decreases with the increasing of tube diameter.