单组分液滴在快速降压环境下传热传质过程研究

为了对降压环境下单个液滴的蒸发过程进行研究，基于气液界面的捕捉模型，建立适用于快速降压环境下单个液滴的蒸发模型，利用纯水液滴蒸发的实验数据验证该模型，分析静止纯水液滴在相变过程中的形态变化以及液滴内部速度场、蒸汽分布等随时间的变化，模拟分析不同压力环境、液滴直径、初始温度等条件对液滴中心温度及蒸发速率的影响。结果表明:在降压蒸发过程中液滴形态和环境中蒸汽的分布会随速度场的变化而变化；液滴中心温度与最终环境压力成正比，液滴初始温度与液滴中心温度的回升速率成正比；最终环境压力对液滴初始阶段的蒸发速率影响较大；液滴初始直径和初始温度对其后期蒸发速率的影响较大。

Study on Heat and Mass Transfer Process of Single Component Droplet Under Rapid Depressurization

Based on the capture of gas-liquid interface with Fick law and VOF (Volume Of Fluid) method, a single droplet evaporation model was established which is suitable for rapid step-down environment, and the new model of pure water droplet evaporation was verified by the experimental results. It was studied that morphological changes of static pure water droplets during phase transition and the changes of temperature field and vapor distribution in the droplet with time. The study simulated and analyzed the influences of droplet center temperature and evaporation rate during different pressure environment, droplet diameter and initial temperature. The results show that the droplet shape and the distribution of vapor in the environment will change with the variation of velocity field in the process of depressurized evaporation, the droplet center temperature is proportional to the final environmental pressure, and the initial temperature is proportional to the rise rate of the droplet center temperature. The final environmental pressure has a great influence on the initial evaporation rate of the droplet, while the initial diameter and initial temperature of the droplet have a great influence on the evaporation rate of the droplet in the later stage.