期刊
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
卷 97, 期 -, 页码 725-734出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ijheatmasstransfer.2016.02.052
关键词
Evaporation; Nanofluid; Nano-particles; Peclet number; d(2)-Law
资金
- NSF
A model is presented for predicting the evaporation behavior of liquid droplets containing nano-sized insoluble particles. The model is constructed based on, and supported by, the existing experimental result. Of particular interest are the evolution of droplet size, and evaporation rate constant prior to the shell formation (also called the first drying or evaporation stage), when the particles forms a compact shell at the droplet surface. As the droplet evaporation proceeds, increasingly more particles are included on its surface, reducing the effective liquid surface area for evaporation causing deviation from the classical d(2)-law for pure fluid droplet evaporation. Peclet number (Pe), a non-dimensional ratio of particle diffusion time to the droplet lifetime, and initial particle concentration (Y-vo) are shown to play a role in the evaporation behavior prior to shell formation. The model predicts that: (1) the deviation from the classical d(2)-law is increasingly significant with increased Pe and Y-vo; (2) the time to shell formation decreases, and shell diameter increases, with increased Pe and initial particle concentration (Y-vo). As a consequence, Y-vo . Pe < 1.8 is necessary for the first stage to exist at all. Within the limiting value, the combination of larger Pe and smaller Y-vo produces larger hollow shells with low densities. For Y-vo . Pe > 1.8 the shell forms instantly and evaporation occurs after liquid diffuses through, and wet, the shell. The effect of contact angle (theta) on the effective liquid surface area for evaporation is also discussed. (C) 2016 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据