Influence of atomization on particle synthesis in spray flames

雾化对喷雾火焰中颗粒合成的影响

• 批准号: 375857587
• 负责人: Professor Dr.-Ing. Reinhold Kneer
• 金额: --
• 依托单位: Lehrstuhl für Wärme- und Stoffübertragung (WSA)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/375857587?language=en
• 关键词: Influence; atomization; particle; synthesis; spray

The spray flame synthesis of nanoparticles is significantly influenced by the atomization of the precursor solutions. The characteristic droplet and gas phase in the vicinity of the nozzle is an essential input condition for the formation of local synthesis conditions in the flame along the trajectories of particles during their formation. Thus, any change of the atomization will directly affect the particle properties. In this context, the nozzle design represents an essential degree of freedom, which can be used to gain a better understanding of the coupling of spray flame and particle formation mechanisms and, on this basis, to enable a targeted manipulation of particle properties in the long term.The high importance of the nozzle geometry for spray flame synthesis was demonstrated by work in the first phase of the current project. It was revealed that an unsuitable atomization can lead to undesired flame pulsations. Since such pulsations prevent a rigorous investigation of the influence of spray characteristics on the process chain of particle formation, an adapted atomizer design was developed which significantly reduces flame pulsations. On this basis and with the help of numerical and experimental investigations, it was shown qualitatively and quantitatively that the particle size distribution can be significantly affected by the selected atomizer design. However, further research is needed to clarify whether and under which conditions a direct correlation between spray characteristics and particle properties exists. Furthermore, it is unknown how the responsible individual mechanisms of particle formation are influenced by the nozzle-dependent local synthesis conditions along the trajectory.Based on this knowledge, this research project aims to provide a fundamental understanding of the influence of local synthesis conditions on spray flame mechanisms by means of a targeted variation of spray characteristics and high-resolution experimental and numerical methods. In this context, we will quantify how and to what extent the formation of local reaction and synthesis conditions is affected by individual nozzle-dependent atomization processes and subsequent droplet-flame interactions. On this basis, a fundamental understanding of the mutual sensitivity of particle formation mechanisms and spray flame mechanisms will be achieved. New atomizer designs will be introduced and used, which allow a systematic variation of the relevant spray flame mechanisms by a specific manipulation of the spray characteristics.

喷雾火焰合成纳米粒子的显着影响的前体溶液的雾化。喷嘴附近的特征液滴和气相是在火焰中沿颗粒形成期间的颗粒轨迹沿着形成局部合成条件的基本输入条件。因此，雾化的任何变化将直接影响颗粒性质。在这种情况下，喷嘴的设计代表了一个重要的自由度，它可以用来获得更好地了解喷雾火焰和颗粒形成机制的耦合，并在此基础上，使有针对性的操纵颗粒的性能在长期。喷嘴的几何形状的高度重要性喷雾火焰合成的工作证明了在当前项目的第一阶段。结果表明，不适当的雾化会导致不希望的火焰脉动。由于这种脉动阻止了对喷雾特性对颗粒形成过程链的影响的严格研究，因此开发了一种适应的雾化器设计，其显著减少了火焰脉动。在此基础上，并与数值和实验研究的帮助下，它被定性和定量地表明，颗粒尺寸分布可以显着影响所选择的雾化器设计。然而，需要进一步的研究来澄清是否以及在何种条件下喷雾特性和颗粒特性之间存在直接的相关性。此外，它是未知的，如何负责的个别机制的颗粒形成的影响，由依赖于喷雾的局部合成条件沿着的轨迹。基于这一知识，本研究项目的目的是提供一个基本的理解，局部合成条件的影响，喷雾火焰的机制，通过有针对性的变化的喷雾特性和高分辨率的实验和数值方法。在这种情况下，我们将量化如何以及在何种程度上形成的局部反应和合成条件的影响，由个人的喷雾依赖的雾化过程和随后的液滴火焰相互作用。在此基础上，对颗粒形成机理和喷雾火焰机理的相互敏感性有了基本的认识。新的雾化器设计将被引入和使用，它允许通过对喷雾特性的特定操纵来系统地改变相关的喷雾火焰机制。