Water droplet growth enhancement through thermal radiation

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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2018

Author dc:creator

• McNichols, Ezra Owen

Contributors dc:contributor

• Brewster, Quinn

• Water
• Droplet
• Radiation

Statement dc:rights

• Copyright 2017 Ezra McNichols

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/99255

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/99255