AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
A Numerical Model to Predict the Morphology of Particle Synthesized via Spray Pyrolysis
SUKRANT DHAWAN, Pratim Biswas, Washington University in St Louis
Abstract Number: 187 Working Group: Nanoparticles and Materials Synthesis
Abstract Spray pyrolysis is an aerosol process widely used for the continuous synthesis of nanoparticles. A precursor solution is usually sprayed into a carrier gas in the form of small droplets. Due to the high temperature of the surrounding gas, the solvent is vaporized, and a concentration gradient of the solute results inside the droplet. The solute gets precipitated and decomposed within the droplet to form particles. Particles with several different morphologies, such as solid and hollow shell, have been produced by spray pyrolysis process. The properties (chemical, electronic, optical) of the particles, and hence their application strongly depends on their composition, size, and morphology. Therefore, it is crucial to understand the different dynamic processes taking place in a droplet, in order to have better and more precise control on the morphology of the synthesized particles via spray pyrolysis. While several models have been developed in the past to predict the particle morphology, these models are missing the whole picture as they do not account for intradroplet reactions, formation, growth, and sintering of particles within the droplet.
In this presentation, a generalized droplet model of coupled heat and mass transfer developed to study the particle formation and predict the final morphology of particle synthesized via spray pyrolysis process will be discussed. The developed model accounts for different dynamic processes taking place during spray pyrolysis, such as droplet evaporation, solute diffusion inside droplet, reaction, and precipitation. The effect of different operating conditions and precursor properties, which influence the morphology of particles will be discussed. The model equations are further cast into dimensionless form for generalization, and the effects of governing dimensionless groups on the particle morphology are evaluated by performing a sensitivity analysis.