Abstract A novel turbulent atomization model, which is physically closed itself and free of case-by-case parameter tuning using experimental data, has been formulated and demonstrated in the framework of turbulent spray combustion large-eddy simulation (LES). Based on our accumulated research findings that elementary droplet/ligament generation is a deterministic phenomenon, not something random as considered in the conventional understanding, the model describes two dominant modes of turbulent atomization, i.e. the turbulent resonant mode and the Rayleigh–Taylor (RT) mode, in a physically straightforward manner. Extending the baseline theory proposed in Umemura (2016), to a hybrid turbulent spray LES formulation which includes both an Eulerian liquid jet core and Lagrangian droplets, the subgrid-scale (SGS) atomization characteristics are completely detailed in this study. Using the LES-resolved turbulent Weber and Bond numbers on the liquid core surface, the atomization mode and the SGS atomization characteristics such as droplet size, number, ejection velocity and core regression velocity are all identified locally, and the information is transferred back to the LES code as input information. Test cases of Diesel fuel jets demonstrate that the present formulation well reproduces the turbulent spray behavior. Thanks to the obtained detailed data, the spray formation process can be tracked both temporally and spatially, from the initial head formation with edge atomization to the later core atomization and spray spreading. It is essentially featured that the present turbulent atomization model works well without ambiguous user input, contrary to the conventional way of spray simulation. This is a significant breakthrough to urge paradigm shift in spray simulation, from unclosed/unpredictable to closed/predictable, which enables drastic improvement in the accuracy of spray simulation and may exert a large impact on both research studies and industrial applications.

中文翻译：

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详细的 SGS 雾化模型及其在两相流 LES 中的实现

摘要 在湍流喷雾燃烧大涡模拟（LES）框架下，建立并论证了一种新的湍流雾化模型，该模型自身物理封闭，无需使用实验数据逐一调整参数。基于我们累积的研究发现，基本液滴/韧带的生成是一种确定性现象，而不是传统理解中考虑的随机现象，该模型描述了湍流雾化的两种主要模式，即湍流共振模式和瑞利-泰勒 (RT)模式，以物理上简单的方式。将 Umemura (2016) 中提出的基线理论扩展到混合湍流喷雾 LES 公式，其中包括欧拉液体喷射核心和拉格朗日液滴，本研究对亚网格尺度 (SGS) 雾化特性进行了详细说明。利用 LES 解析出的液核表面湍流韦伯和邦德数，雾化模式和 SGS 雾化特征如液滴尺寸、数量、喷射速度和核回归速度等都在本地识别，并将信息传回LES 代码作为输入信息。柴油燃料喷射的测试案例表明，本配方很好地再现了湍流喷雾行为。由于获得了详细的数据，可以在时间和空间上跟踪喷雾形成过程，从最初的头部形成边缘雾化到后来的核心雾化和喷雾扩散。与传统的喷雾模拟方式相反，本发明的湍流雾化模型的本质特点是无需模糊的用户输入即可运行良好。这是推动喷雾模拟范式转变的重大突破，从不封闭/不可预测到封闭/可预测，这将大大提高喷雾模拟的准确性，并可能对研究和工业应用产生重大影响。