A Water Droplet Evaporation and Temperature Model

Abstract

ABSTRACT Amodel for predicting evaporation and temperature changes in water drops traveling through air was developed and evaluated with laboratory data. The model uses combined sensible heat transfer and diffusion theory in an energy balance to simultaneously calculate evaporation as droplet temperature approaches wet bulb temperature of the air. Predicted droplet temperatures agreed closely with measured temperatures. The evaporation portion of the model was evaluated by measuring loss of water over longer time periods after the droplet reached wet bulb temperature. A volumetric method using microliter syringes was used to measure evaporation loss from 0.5 to 2 mm diameter drops. Model predictions generally agreed with measured rates.