Process analysis and control of atomization and mixing zones in spray flames

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The synthesis of nanoparticles in spray flames results from the interplay of complex chemical and physical processes (multiphysics and chemical reaction: precursor and gas supply, atomization, spray formation, droplet evaporation, reaction chemistry, particle synthesis and formulation). These phenomena occur on substantially varying time and length scales. In order to optimize the existing technology and to develop new approaches for an efficient implementation and process control at the technical level, the individual processes and their interplay needs to be understood from a fundamental point of view. The proposed project aims at a detailed process analysis and control of the primary process steps (precursor chemistry, atomization, reaction, mixing, and entrainment) in order to reveal potentials for further process optimization. A main hypothesis of this project is that the mixing and reaction zones can be controlled and optimize by the targeted adjustment of gas flows, and by adding and recirculating quenching gases. Detailed studies of droplet-droplet and droplet-gas interactions can reveal group combustion phenomena and evaporation kinetics from spatially and temporary resolved measurements. The influence of precursor concentrations on temperature, as well as on droplet evaporation and particle nucleation provide deep insights into the droplet and particle histories. The close connections and control of atomization, droplet evaporation and reaction is a key step to tap the full potential of flame spray pyrolysis and to design proper process routes for the tailored synthesis of functional materials.