This paper presents a comparison of experimental and numerical results for a series of turbulent reacting jets where silica nanoparticles are formed and grow due to surface growth and agglomeration. We use large-eddy simulation coupled with a multiple mapping conditioning approach for the solution of the transport equation for the joint probability density function of scalar composition and particulate size distribution. The model considers inception based on finite-rate chemistry, volumetric surface growth and agglomeration. The sub-models adopted for these particulate processes are the standard ones used by the community. Validation follows the “paradigm shift” approach where elastic light scattering signals (that depend on particulate number and size), OH- and SiO-LIF signals are computed from the simulation results and compared with “raw signals” from laser diagnostics. The sensitivity towards variable boundary conditions such as co-flow temperature, Reynolds number and precursor doping of the jet is investigated. Agreement between simulation and experiments is very good for a reference case which is used to calibrate the signals. While keeping the model parameters constant, the sensitivity of the particulate size distribution on co-flow temperature is predicted satisfactorily upstream although quantitative differences with the data exist downstream for the lowest coflow temperature case that is considered. When the precursor concentration is varied, the model predicts the correct direction of the change in signal but notable qualitative and quantitative differences with the data are observed. In particular, the measured signals show a highly non-linear variation while the predictions exhibit a square dependence on precursor doping at best. So, while the results for the reference case appear to be very good, shortcomings in the standard submodels are revealed through variation of the boundary conditions. This demonstrates the importance of testing complex nanoparticle synthesis models on a flame series to ensure that the physical trends are correctly accounted for.

中文翻译：

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在不同流入条件下，由硅烷射流合成二氧化硅的稀疏-拉格朗日 PDF 建模

本文比较了一系列湍流反应射流的实验和数值结果，其中二氧化硅纳米粒子由于表面生长和团聚而形成和生长。我们使用大涡模拟和多重映射调节方法来求解标量成分和颗粒尺寸分布的联合概率密度函数的输运方程。该模型考虑了基于有限速率化学、体积表面生长和团聚的初始。这些微粒过程采用的子模型是社区使用的标准模型。验证遵循“范式转变”方法，其中弹性光散射信号（取决于颗粒数量和大小），OH- 和 SiO-LIF 信号是根据模拟结果计算的，并与来自激光诊断的“原始信号”进行比较。研究了对诸如协流温度、雷诺数和射流的前体掺杂等可变边界条件的敏感性。对于用于校准信号的参考案例，模拟和实验之间的一致性非常好。在保持模型参数不变的情况下，尽管对于所考虑的最低合流温度情况，下游存在与数据的定量差异，但上游的颗粒尺寸分布对合流温度的敏感性得到了令人满意的预测。当前体浓度发生变化时，模型预测信号变化的正确方向，但观察到数据的显着定性和定量差异。特别是，测量的信号表现出高度非线性的变化，而预测最多表现出对前驱体掺杂的平方依赖关系。 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 因此，虽然参考案例的结果看起来非常好，但标准子模型的缺点会通过边界条件的变化暴露出来。这表明在火焰系列上测试复杂的纳米颗粒合成模型的重要性，以确保正确考虑物理趋势。