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. (C) 2012 Elsevier B.V. All rights reserved.