Evaporation effect on two-dimensional wicking in porous media

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:514

Article

Petsev, Dimiter N.¹ 

[1] Univ New Mexico, Dept Chem & Biol Engn, Albuquerque, NM 87131 USA

关键词: Capillarity;    Porous media;    Evaporation;   

DOI  :  10.1016/j.jcis.2017.12.004

来源: Elsevier

【 摘 要 】

We analyze the effect of evaporation on expanding capillary flow for losses normal to the plane of a two-dimensional porous medium using the potential flow theory formulation of the Lucas-Washburn method. Evaporation induces a finite steady state liquid flux on capillary flows into fan-shaped domains which is significantly greater than the flux into media of constant cross section. We introduce the evaporation-capillary number, a new dimensionless quantity, which governs the frontal motion when multiplied by the scaled time. This governing product divides the wicking behavior into simple regimes of capillary dominated flow and evaporative steady state, as well as the intermediate regime of evaporation influenced capillary driven motion. We also show flow dimensionality and evaporation reduce the propagation rate of the wet front relative to the Lucas-Washburn law. (C) 2017 Elsevier Inc. All rights reserved.

【 授权许可】

Free