基于气相扩散模型的液滴蒸发动力学特性

Dynamics of Evaporating Droplet Based on Gas Phase Diffusion Model

  • 摘要: 基于润滑理论和气相扩散与液滴蒸发之间的相互耦合作用, 建立液滴在均匀壁温固体基底上蒸发的数学模型, 推导出基于气相扩散模型的液滴厚度演化方程; 结合液滴接触线动力学求解准静态气相场, 通过数值计算分析气相作用下马兰戈尼数(Ma)和佩克莱数(Pek)对液滴蒸发进程的影响。结果表明: 与单边模型相比, 采用气相扩散模型时的液滴蒸发进程更慢、接触半径更小、蒸发速率更低, 其结果与实验结果更符合; 在气相扩散模型下, 减小Ma可增大液滴蒸发速率, 促进液滴蒸发; 增大Pek, 液滴附近的气体密度增大, 液滴蒸发速率加快。

     

    Abstract: Based on the lubrication theory and the coupling between gas phase diffusion and droplet evaporation, a mathematical model of droplet evaporation on a solid substrate with uniform wall temperature is established, and the evolution equation of droplet thickness based on the gas phase diffusion model is derived. The quasi-static gas phase field is solved with the droplet contact line dynamics, and the influence of Ma and Pek on the droplet evaporation under the effect of gas phase is discussed through numerical simulation. The results show that under the same parameters, the droplet evaporation process of the gas phase diffusion model is slower than that of the one-sided model, and the contact radius and the evaporating rate is decreased, and the results are more consistent with the experimental results. Under the gas phase diffusion model, the droplet evaporating rate is increased and the droplet evaporation process is shortened by reducing Ma, thereby promoting droplet evaporation. By increasing Pek, the gas density near the droplet is densified, and the droplet evaporation is enhanced.

     

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