EVAPORATION FROM ACCELERATING DROPLETS
A liquid drop breaking away from a feeding orifice or a liquid film and falling through a gaseous environment of lower temperature experiences simultaneous heat and mass transfer. The modelling of drop cooling rates are complicated by the transient nature of the drop motion due to acceleration, the onset of internal circulation inside the drop and drop shape oscillations.
The cooling rate of an array of mono-dispersed water drops with diameters between 2.5 and 6.1 mm, falling in an upward-flowing air stream with air velocities between 0.5 and 2.5 in/s, was determined experimentally for drops falling through heights between 1.1 and 3.1 in. Correlations for the governing heat and mass transfer coefficients were determined from the experimental data.