Generation of monodisperse aerosols through condensation nuclei control

Abstract

A device for the generation of monodisperse aerosols through condensation nuclei control has been designed and tested in the present study. A continuous flow, evaporation-condensation aerosol generator has been designed to produce monodisperse aerosols of low vapor pressure organic liquids, such as dioctyl phthalate (DOP), at flow rates over 2.5 lpm. Nebulised NaCl particles are passed through the particle number controller to reduce the number concentration close to 10 5 /cc to suppress homogeneous condensation. The condensation nuclei with nitrogen as a carrier gas are passed through a bubbler containing DOP, producing a nuclei-vapor mixture. The mixture is condensed producing the aerosols of narrow size distribution. A heater section previous to the condenser section provides complete evaporation across the tube diameter, while the condenser walls in free convection create a low temperature gradient, both of which enhance aerosol monodispersity. The results show that controlling the nuclei number concentration as well as vapor source can produce aerosols with sufficient monodispersity.