单液滴蒸发影响因素实验研究

Experimental research on single droplet evaporation factors

设计了液滴蒸发实验装置,利用高速摄像系统记录高温气流中液滴蒸发过程,并根据实验的数据总结出液滴蒸发规律。在蒸发过程中,液滴蒸发首先经历一个非稳态初始加热阶段,然后液滴蒸发进入一个相对稳定的蒸发阶段,其直径变化基本遵循D2定律。气流温度越高,气流速度越大,液滴蒸发时间越短,液滴蒸发速度越快,但是气流速度对蒸发影响很小。随着液滴初始直径的增大,内部环流加强,液滴后部的尾涡加大,传质阻力减小,液滴的蒸发常数变大。

Droplet evaporation equipment is founded. High-speed camera system is used to record the process of droplet evaporation in high-temperature airflow. Droplet evaporation law is summarized in accordance with the experimental data. In the evaporation process, the droplet firstly experiences the non-steady-state heating stage. Then the droplet evaporation goes into a relatively stable stage and the diameter changes in general conformity with the D2 law. The higher the air temperature and the greater the flow velocity, the shorter the droplet evaporation time and the the faster the droplet evaporation. However, the flow velocity has little effect on evaporation process. With the increase of the droplet initial diameter,the internal circulation enhances and the trailing vortex behind the droplet increases. At the same time, the mass transfer resistance decreases and the droplet evaporation constant becomes larger.