This work is a first direct numerical simulation of a configuration closely related to the SpraySyn burner (Schneider et al. in Rev Sci Instrum 90:085108, 2019). This burner has been recently developed at the University of Duisburg-Essen to investigate experimentally nanoparticle synthesis in spray flames for a variety of materials. The present simulations are performed for ethanol and titanium tetraisopropoxide as a solvent and precursor, respectively, in order to produce titanium dioxide nanoparticles. In the direct numerical simulations, the complete scenario leading to the production of well-defined nanoparticles is taken into account, including evaporation of the liquid mixture (solvent and precursor) injected as a spray, multi-step kinetics for gas-phase combustion, and finally nanoparticle synthesis. The employed models are described in this article. Additionally, the impact of the inlet velocity of the pilot flame on the nanoparticle synthesis is investigated. It has been found that increasing this speed delays spray flame ignition, decreases nanoparticle concentration, but leads to a narrower size distribution at early stage.

中文翻译：

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DNS 研究的湍流喷射火焰中纳米颗粒的形成和行为

这项工作是对与 SpraySyn 燃烧器密切相关的配置的首次直接数值模拟（Schneider 等人在 Rev Sci Instrum 90:085108, 2019 中）。这种燃烧器最近在杜伊斯堡-埃森大学开发，用于研究各种材料在喷雾火焰中的纳米颗粒合成实验。本模拟分别针对乙醇和四异丙醇钛作为溶剂和前体进行，以生产二氧化钛纳米颗粒。在直接数值模拟中，考虑了导致产生明确定义的纳米粒子的完整场景，包括作为喷雾注入的液体混合物（溶剂和前体）的蒸发，气相燃烧的多步动力学，以及最后合成纳米粒子。本文描述了所采用的模型。此外，还研究了引燃火焰入口速度对纳米颗粒合成的影响。已经发现，增加该速度会延迟喷雾火焰点火，降低纳米颗粒浓度，但会导致早期尺寸分布变窄。