Study on the shape and temperature variations within droplet in low pressure environment

When a water droplet is placed suddenly into low-pressure environment from an atmospheric pressure, it changes from initial equilibrium state to superheated state, so flashing begins. The variations of the shape and temperature within the droplet are described, and the effect of environment pressure and initial temperature on the temperature variation during stable evaporation and stable freezing process was summed up. The experimental results show that the flash of droplet can be divided into six kinds of shape. During a stable evaporation process, the ultimate temperature declined with a decrease in environment pressure, and it used more time dropping to the ultimate temperature when the initial droplet temperature was higher. While in stable freezing process, the freezing start temperature and the highest recovery temperature were both increased with an increase in initial droplet temperature, but they were declined when the environment pressure was increased.