A Model for Multi-Component Evaporation of Aerial Sprays

Abstract

Droplet evaporation models, such as the one in AGDISP, make use of a single evaporation constant for active, additive, and carrier components of the aerial spray. A general approach to droplet evaporation suggests the need for modeling the evaporation rates of the three components separately and independently. The proposed approach discussed herein extends the single droplet evaporation model by making several assumptions also made in work on the evaporation of multi-component jet fuels. For example, the model treats the computation of evaporation from an isolated droplet composed of three distinct components with the assumption of rapid internal mixing, implying that the components within a droplet mix so fast that at any instant the mass fraction of each component is approximately spatially uniform. This assumption is especially helpful near the surface of the droplet, since the mixture properties at the surface dominate the evaporation rate for the various components. The intent of the paper is to develop a working evaporation model and provide initial examples of its application.