液滴干燥过程的模拟研究

Simualtion of Solution Droplet Drying Process

为更直观地体现液滴蒸发历程,详细分析液滴内部溶剂浓度与液滴比热、液滴表面饱和蒸气压、溶剂扩散系数之间的耦合关系,建立同时考虑液滴内部温度梯度变化及浓度梯度变化的单液滴蒸发模型,并基于网格重构技术解决液滴蒸发过程中的动边界问题,分别以纯水滴和硫酸钠溶液液滴蒸发为例,模拟分析不同操作工况下,液滴滴径、液滴内部温度梯度及溶质浓度梯度的瞬态变化。结果表明:数值模拟的结果与实验结果基本吻合。

In order to indicate the droplet evaporating process directly, analyze the coupled relationship of solvent percentage, droplet specific heat, saturated vapor pressure and solvent diffusion coefficient, a new evaporation model was founded, taking account of the changing of temperature gradient and concentration gradient. Also, the moving boundary problem was solved according to the mesh-reconstruction technology. Taking the evaporation process of drop and sodium sulfate solution for example, the transient variation of drop diameter, inner temperature gradient, inner solute concentration gradient were analyzed under the different operating conditions. It was shown that the predicted results agreed well with the experimental data.