HEAT AND MASS TRANSFER CONTROL BY EVAPORATIVE THERMAL PATTERNING OF THIN LIQUID LAYERS

Abstract

For several years, interfacial instabilities arising in evaporating layers of volatile liquid when subjected to a shear flow of inert and non-absorptive gas have been studied for their intrinsic complexity due to the interaction between different phenomena such as heat and mass transfer through the layer interface, thermo-capillarity, natural convection, and shear-induced stresses. More recently, the possibility of generating ordered thermal patterns in an evaporating layer by controlling such kinds of instabilities has been considered as an intriguing technique to enhance heat and mass transfer in precisely defined spots at the interface of the layers. We studied numerically the topology of the thermal patterns as well as the heat and mass transfer characteristics that can be induced in an evaporating liquid layer by controlling the thickness of the layer while keeping constant the gas flow intensity. Calculations have been conducted by considering ethanol as the working fluid and nitrogen as the inert gas. The thickness of the layer was varied in order to have aspect ratios with respect to the characteristic length of the evaporating interface in the range of 0.02-1. The inspiring reason for performing the simulations reported in this paper is the preparation of the CIMEX-1 experiment that will be performed on-board the International Space Station in the next future. For that reason, all the calculations presented refer to the condition of the absence of gravity. © 2011 by Begell House, Inc.