Thermocapillary Convection with Phase Transition in the 3D Channel in a Weak Gravity Field.

The regimes of joint flows of the evaporating liquid and vapor-gas mixture in a 3D rectangular channel are studied with the help of a partially invariant solution for the convection equations. The effects of thermodiffusion and diffusive thermal conductivity in the gas–vapor phase are additionally taken into account in the governing equations and under interface conditions. A numerical simulation of the 3D fluid flows is carried out for the liquid–gas system like ethanol–nitrogen and HFE-7100–nitrogen under microgravity conditions. The influence of the thermal load, liquid layer thickness and heat-transfer liquid type on the structure of the fluid flows and evaporation characteristics is investigated. The solution allows one to describe the formation of longitudinal thermocapillary rolls observed in the experiments. The evaporative mass flow rate depends essentially on the thermophysical properties of the working liquid. Spatial size and a shape of thermal patterns are determined by the applied thermal load and they can be varied with the change in the liquid layer thickness. Topological structure of the flows (double or quadruple vortex composition) is defined by the combined influence of the thermocapillary and convective mechanisms and phase transition effects. The results discussed in the paper provide motivation for the development of a classification of the 3D flow regimes similar to the Napolitano's classification for 2D flows. [ABSTRACT FROM AUTHOR]