Experimental investigation of the hydrodynamics and stability of an evaporating wetting film placed in a temperature gradient

This paper describes an experimental investigation of the hydrodynamics of an evaporating meniscus in a capillary tube where a temperature gradient is applied along the wall. A capillary tube is plunged into a pool of a volatile liquid; the liquid is allowed to rise under the capillary effect. A heater is placed at the edge of the capillary to provide localized heating. Visual observation allows determination of the influence of the temperature gradient along the wall on the wetting behaviour of the meniscus. The liquid is seeded with tracers and the convection inside the liquid is characterized using particle image velocimetry (PIV). The results show that the ability of the evaporating meniscus to wet the capillary tube is degraded by a temperature gradient along the wall. The convection observed is strongly influenced by the temperature gradients along the wall. (C) 2004 Elsevier Ltd. All rights reserved.