Evaporative heat and mass transfer from the free surface of a liquid wicked into a bed of spheres
Abstract
Evaporation of ethanol from square packed arrays of 3.95 mm diameter copper spheres in a transparent, enclosed chamber is investigated. The enclosure ensures that relatively saturated vapor conditions exist near the free surface. The desired heat flux is imposed on the copper substrate upon which the copper spheres are mounted, and the liquid level in the bed is maintained by wicking from a continuous supply of liquid provided by a syringe pump. Transparent windows in the enclosure allow for visualization of the evaporating liquid meniscus shape, which is recorded for different liquid feeding rates and heat fluxes. Experimentally measured meniscus profiles are compared to analytical results based on surface-energy minimization. A meniscus microregion is defined from the contact line to the length where the liquid thickness reaches 10 mu m. An approximate kinetic theory-based analysis estimates that up to similar to 55% of the total meniscus mass transfer occurs in this microregion. (C) 2011 Elsevier Ltd. All rights reserved.
Keywords
Phase change; Evaporation; Thin film; Liquid-vapor interface; Heat pipe; Sintered material; THIN-FILM; VISUALIZATION; MENISCUS
DOI
10.1016/j.ijheatmasstransfer.2011.03.042
Citation
International Journal of Heat and Mass Transfer Volume 54, Issues 15–16, July 2011, Pages 3440–3447
Date of this Version
7-2011
Recommended Citation
Migliaccio, Christopher P. and Garimella, Suresh V., "Evaporative heat and mass transfer from the free surface of a liquid wicked into a bed of spheres" (2011). Birck and NCN Publications. Paper 986.
http://dx.doi.org/10.1016/j.ijheatmasstransfer.2011.03.042