Drying of a liquid droplet suspended in its own vapour

Abstract

We consider the spray drying of colloidal solutions or sols, a process that leads to the production of nanoporous powders, which are of importance in numerous manufacturing applications. An initial model of this process is formulated by considering the evaporation of a liquid droplet suspended in its own vapour. Mass, momentum, and energy balances are given for the liquid and vapour phases of the problem. Perturbation analysis shows that the system is effectively isobaric, and it is shown that surface tension may be neglected. The subsequent moving boundary problem is solved numerically and the results of this process are presented.