Experimental Investigation on Flash Evaporation of Saltwater Droplets Released into Vacuum

In this paper, the flash evaporation process of saltwater droplets released into vacuum is experimentally investigated. During the experiment, a saltwater (NaCl) droplet was suspended on a thermocouple junction, which was used to measure the temperature evolution. The droplet surface temperature was captured by an infrared thermal imager, and the shape variation was recorded by a high speed camera. According to the experimental results, the component and solution concentration has great influence on the evaporation process. With a rise of salt concentration in water, the evaporation rate decreases. The shape of temperature transition curve also depends on the salt concentration in solution, no matter whether it is higher or lower than the eutectic point (22.4%). The effects of environmental pressure, initial droplet temperature and initial droplet diameter on the temperature transition of droplets were also summarized based on the experimental data.