Evaporation Properties of Water through Floating Porous Structures for Desalination

Abstract

The floating porous structure consists of an optical absorption layer, a porous layer, and an insulating layer. Water is pumped through a porous structure to the top absorption surface for evaporation. A numerical model of interfacial evaporation of floating porous structure is established. A multiphysical field coupling model for heat transfer, flow, and mass transfer within porous structures is simulated. The transient temperature response, evaporation flux, and vapor concentration distribution inside the structure are calculated. Effects of porous structure characteristics, such as size and porosity, on evaporation performance are discussed. With the increase of structure radius, the evaporation amount increases gradually, but the evaporation per unit area decreases with the radius. With the increase of the structure height, the evaporation amount and the evaporation flux decrease, but the decrease is relatively small. The porosity of the porous layer ε1 has a significant effect on the evaporation performance. The increase of ε1 is beneficial to the evaporation of water. When ε1 < 0.3, the effect of the porosity of insulation layer ε2 on the evaporation performance can be neglected.