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

喷雾火焰中纳米颗粒的合成是复杂的化学和物理过程（多物理场和化学反应：前驱体和供气、雾化、喷雾形成、液滴蒸发、反应化学、颗粒合成和配方）相互作用的结果。这些现象在不同的时间和长度尺度上发生。为了优化现有技术并为技术一级的有效执行和过程控制开发新的方法，需要从基本观点了解各个过程及其相互作用。该项目旨在对主要工艺步骤（前体化学、雾化、反应、混合和夹带）进行详细的工艺分析和控制，以揭示进一步工艺优化的潜力。本项目的一个主要假设是，通过有针对性地调节气体流量，并通过添加和循环淬火气体，可以控制和优化混合和反应区。对液滴-液滴和液滴-气体相互作用的详细研究可以从空间和临时分辨测量中揭示群体燃烧现象和蒸发动力学。前驱体浓度对温度的影响，以及对液滴蒸发和颗粒成核的影响，为液滴和颗粒的历史提供了深刻的见解。雾化、液滴蒸发和反应的紧密联系和控制是充分挖掘火焰喷雾热解潜力，设计合适的工艺路线以定制合成功能材料的关键步骤。

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.