THE EVAPORATION, TEMPERATURE AND THERMAL RELAXATION-TIME OF FREELY FALLING WATERDROPS

Abstract

A theoretical and experimental study of the physical behavior of freely falling waterdrops is carried out. The influence of ventilation and environment upon the evaporation and equilibrium temperature is formulated in quantitative terms. The theoretical approach emphasizes the vapor and heat transferred to packets of environmental air that make transient contact with the liquid sphere. The basic psychrometric equation is derived for a freely-falling spherical drop. Measurements of the evaporation, equilibrium temperature and time to reach equilibrium were carried out for single drops and compared with theory. Evaporation data are presented for drops from the largest size down to those of cloud size. New methods and apparatus especially devised to study freely falling drops are described.