低压环境下海水液滴蒸发模型研究

针对低压环境下的多种盐分组成的海水液滴(NaCl、MgCl_2、CaCl_2、KCl的质量分数分别为20.07%、1.29%、0.412%、0.399%)的蒸发过程进行了模型研究,模型将能量守恒方程和传质扩散方程进行耦合。通过模型计算,分析了液滴内组分含量和温度分布随时间的变化,获得了环境压力和环境温度对液滴温度变化的影响。结果表明,在蒸发过程中,液滴内部的各种盐含量升高过程不是成单一的线性增加的,在液滴的蒸发和内部盐含量扩散的共同作用下,盐含量表现出在先快速上升之后,逐渐下降继而又有所回升的趋势。液滴温度下降至最低温度后,也逐渐回升。并且环境压力越低,液滴温度下降越快,最低温度越低,温度回升越快。环境温度越高,液滴最低温度越高,温度回升越快。

Numerical Study of Evaporation of a Seawater Droplet under Low Pressure Environment

An effective numerical model is established to analyze the evaporation process of sea droplets composed of various salts (NaCl, MgCl2 , CaCl2 , and KCl with mass fraction of 20.07%, 1.29%, 0.412%, and 0.399% respectively) at low pressure environment. The model coupled energy conservation equation with mass transfer diffusion equation. Through the calculation of the model, the variation of the content and temperature distribution in the droplet with the time was analyzed, also the effects of environmental pressure and ambient temperature on the change of droplet temperature was obtained. The results showed that, during the evaporation process, the content of various salts inside the droplets was not a single linear increasing. The content of salt contained three phases, rises rapidly, gradually decreases and then rises slowly again under the combination of the evaporation of droplets and the diffusion of internal salt content. After the droplet temperature dropped to the lowest temperature, it gradually recovered also. The decrease velocity of the droplet temperature decreased with the ambient pressure decreases. In addition, there were higher minimal temperature and faster temperature recovery rate when the ambient temperature was higher.