Water droplet growth enhancement through thermal radiation

Water;Droplet;Radiation

McNichols, Ezra Owen ; Brewster ; Quinn

关键词: Water;    Droplet;    Radiation;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/99255/MCNICHOLS-THESIS-2017.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

This thesis explores how thermal radiation affects water droplet growth in the 20 to 100 μm size range. The theory of mass and energy transfer involving thermal radiation for a single droplet is presented. This theory is then extended to predict droplet growth for a given droplet distribution exposed to a controlled radiative sink. In the model, mass and energy transfer between the droplets and their surroundings are considered. The theoretical model predicts that droplets above approximately 2 μm will experience growth by condensation while smaller droplets will experience evaporation. An experiment was also conducted to measure the effect thermal radiation has on a droplet distribution and was compared to calculations from the theoretical model. Experimental data shows droplet growth occurring at a much higher rate than theoretical predictions. This leads the author to believe either the theoretical model is ignoring another growth mechanism or there is a limiting assumption being implemented in the model. Droplet growth is shown, theoretically and experimentally, to be in agreement with the time scales of droplet growth observed in nature. The time for a small droplet to achieve the size of a rain drop is predicted in this model to be on the order of minutes. Ignoring thermal radiation results in a time scale on the order of days rather than minutes.