Fluid-particle dynamics during combustion spray aerosol synthesis of ZrO

Owing to its versatility and low cost, flame spray pyrolysis (FSP) is becoming an increasingly promising method for industrial production of a broad spectrum of nanoparticles. To assist understanding and scale-up of the current laboratory process, a computational model has been constructed for the example of zirconia nanoparticle synthesis. Therefore, a computational fluid dynamics (CFD) description of the spray flame originating from a twin-fluid atomizer and coaxial diffusion burner was combined with droplet and nanoparticle dynamics. The model predicted well average primary ZrO₂ particle diameters even though global chemical reactions, immediate nanoparticle formation upon precursor oxidation and monodisperse particle dynamics were employed. This model is self-containing and does not rely on experimental input data such as temperature or velocity fields. The model was validated at different process conditions with phase-Doppler anemometry (PDA) for spray characteristics, Fourier-transform infrared spectroscopy (FTIR) flame temperature measurements as well as nanoparticle sampling in and above the flame.