Modelling of nanoparticle formation during spray pyrolysis

Area of Science:

• Chemical Engineering
• Materials Science
• Fluid Dynamics

Background:

• Droplet evaporation is critical in processes like spray drying and pyrolysis.
• Understanding particle morphology (solid vs. hollow) is essential for material properties.
• Non-continuum effects become significant for micro- and nano-sized droplets.

Purpose of the Study:

• To develop a mathematical model for micro- and nano-sized droplet evaporation.
• To predict the formation of solid or hollow particles.
• To incorporate non-continuum effects into droplet evaporation modeling.

Main Methods:

• Developed a mathematical model combining continuum equations with an interpolation formula for the Boltzmann equation.
• Modeled droplet evaporation considering non-continuum effects in the transition regime.
• Validated model predictions against experimental data for submicron zirconia particles.

Main Results:

• Non-continuum effects significantly impact submicron and nano-sized droplet evaporation at atmospheric pressure.
• Developed correlations for final particle size and wall thickness based on process parameters.
• Model predictions showed good agreement with experimental results for spray pyrolysis.

Conclusions:

• The developed model accurately predicts particle morphology from droplet evaporation.
• Non-continuum effects are critical for accurate modeling of micro/nano-droplet evaporation.
• The study provides valuable correlations for optimizing particle synthesis in spray drying and pyrolysis.