An experimental and numerical study of capillary rise with evaporation

An experimental and numerical study of spontaneous imbibition into capillary tubes subject to phase change is presented. A mathematical model is developed to predict the motion of a meniscus while undergoing phase change. The model addresses slip at the wall, viscous effects of the vapour in the capillary tube and transient evaporation. A set of experiments were performed for three fluids (acetone, n-pentane and iso-octane), three capillary tube diameters (0.5, 1.0, and 2.0 mm) and five heating conditions (0, 0.7, 2.7, 6.0 and 10.6 W). The experimental results demonstrated that the meniscus rise was altered by varying degrees of evaporation. A comparison of the experimental data and the mathematical model yielded a good correlation for the 1 mm capillaries, and deviated for both the 0.5 mm and 2 mm cases. It was found that an asymptotic transient mass function was unable to improve the fit to experiment.