Electrospray evaporation and deposition

Abstract

Electrospray transport, evaporation and deposition on a heated substrate is investigated theoretically by Lagrangian tracking of single droplets. The droplet mass and heat transfer are calculated under forced convection and compared to limited cases of electrospray transport only or droplet evaporation only. Segregation of primary and satellite electrospray droplets is observed also, in agreement with data in the literature. The arriving droplet diameter and spatial distribution at the substrate show that evaporation barely affects droplet transport. In contrast, droplet size and salt concentration can be affected significantly by evaporation. It is shown also how process parameters such as substrate temperature, initial droplet diameter and vapor transport may affect the film quality. Accounting for the Rayleigh limit of charged droplets, leads to acceleration of their evaporation when high substrate temperatures or small droplet diameters are employed.