ABSTRACT
In gas and hydrodynamic problems with the boundary conditions on solid surfaces the velocity components are equated to zero, based on the condition that the particles of the substance on the walls are so strongly attracted that their velocity vanishes. The complex nature of the dynamics of fluid flow with high density in the presence of capillary condensation is illustrated by the movement of a vapour bubble. The thermodynamic treatment of capillary flow connects it to the curvature of the meniscus of the vapour–liquid interface and the use of the Kelvin equation for the quantitative description of the driving force of the flow. The conservation of the bubble shape can be treated as the volumetric flow, with retention of the molecular distribution near the wall, as in the case the film flow regime. From the molecular point of view, the principle of the observed phenomenon is the realization of two opposing mechanisms of molecular motion.
