Natural convection in pools of evaporating liquids

Abstract

In this exploratory study, schlieren photography has been used to reveal a variety of convection patterns in pools of evaporating liquids. Pure materials as well as binary solutions were investigated, both in the presence and absence of surface contamination, which was shown to exert a considerable influence on the convective flow. It was found that, with the exception of water, the observed flow structures were largely dependent on the depth of the evaporating pool and to a much lesser extent on the properties of the liquid. Also, it was possible to identify certain flow patterns as being induced by a surface-tension-driven instability and others as being due to buoyancy-driven convection; still other patterns seemed to be uniquely associated with the presence of surface contamination.