Exploration of the effects of pressure and temperature on the evaporation rate of selected liquids

Abstract

The rate of evaporation of liquids has been a topic of research for over a century. A detailed understanding of this phenomena is required to make scientific advancements in various areas. The principal objective for conducting this work was to study the effect of pressure on the rate of evaporation of liquids in close to equilibrium conditions, and further increase the much needed lack of existing data sets for evaporation of liquids in any such controlled environment. The experimental setup involved two glass cannisters, each containing four glass capillaries. The capillaries were filled with liquid at various levels, and tests were preformed at fixed temperatures while the containers maintained vacuum. This initial condition was not at equilibrium and liquid from the capillaries slowly evaporated. By measuring the change in liquid height in the capillaries the net rate of evaporation was estimated. The experimental results suggested that even though, as thought before, pressure has a role in determining the rate of evaporation of liquids, for the case where the evaporation takes place from a receding meniscus inside a capillary tube, the rate of vapor diffusion out and away from an evaporating meniscus could be equally as important, and the pressure build up above an evaporating meniscus entrapped inside a capillary tube could impede the evaporation rate.