Microdynamics of the Early Stages of Liquid/Plate Contact under Highly Nonequilibrium Conditions

Abstract

A microhydrodynamic approach (in which the dissipative coefficients are calculated using the molecular model of lattice gas) is used to study the upward flow of a liquid film over a hydrophilic plate immersed partially in a liquid and to investigate the formation of a meniscus on this plate. The early stages of the unsteady-state transport of a dense fluid over the plate surface (argon–carbon system) are studied numerically. The method enables one to investigate the distributions of molecules and their velocities at different distances from the plate surface. The variation of the concentration fields from the flow origination to the establishment of a quasi-steady state is examined. The contact angle velocity is found (this angle determines the meniscus boundary). It is shown that two types of contact angles can be distinguished in the meniscus-motion dynamics, which correspond to two different molecular scales. The mechanism of the formation of a liquid film and the upward and downward flows of the film on the plate surface at the molecular level (on small spatial scales, where gravity makes no contribution) are discussed. The evolution of a cylindrical drop over the open plate surface is considered.