Abstract Engine fuel spray modeling still remains a challenge, especially in the dense near-nozzle region. This region is difficult to experimentally access and also to model due to the complex and rapid liquid and gas interaction. Modeling approaches based on Lagrangian particle tracking have failed in this area, while Eulerian modeling has proven to be particularly useful. Interface resolved methods are still limited to primary atomization academic configurations due to excessive computational requirements. To overcome those limitations, the single-fluid diffuse interface model known as Σ-Y, arises as a single-framework for spray simulations. Under the assumption of scale separation at high Reynolds and Weber numbers, liquid dispersion is modeled as turbulent mixing of a variable density flow. The concept of surface area density is used for representing liquid structures, regardless of the complexity of the interface. In this work, a LES based implementation of the Σ-Y model in the OpenFOAM CFD library is applied to simulate the ECN Spray A configuration. Model assessment is performed for both near- and far-field spray development regions using different experimental diagnostics available from ECN database. The CFD model is able to capture near-nozzle fuel mass distribution and, after Σ equation constant calibration, interfacial surface area. Accurate predictions of spray far-field evolution in terms of liquid and vapor tip penetration and local velocity can be simultaneously achieved. Model accuracy is lower when compared to mixture fraction axial evolution, despite radial distribution profiles are well captured.

中文翻译：

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近场和远场燃料密集喷雾的 LES 欧拉扩散界面建模

摘要 发动机燃油喷雾建模仍然是一个挑战，尤其是在密集的近喷嘴区域。由于复杂且快速的液体和气体相互作用，该区域难以通过实验进入，也难以建模。基于拉格朗日粒子跟踪的建模方法在这方面失败了，而欧拉建模已被证明特别有用。由于过多的计算要求，界面解析方法仍然仅限于初级原子化学术配置。为了克服这些限制，称为 Σ-Y 的单流体扩散界面模型作为喷雾模拟的单一框架出现。在高雷诺数和韦伯数下水垢分离的假设下，液体分散被建模为可变密度流的湍流混合。无论界面的复杂程度如何，表面积密度的概念都用于表示液体结构。在这项工作中，OpenFOAM CFD 库中 Σ-Y 模型的基于 LES 的实现被应用于模拟 ECN Spray A 配置。使用 ECN 数据库中提供的不同实验诊断，对近场和远场喷雾发展区域进行模型评估。CFD 模型能够捕捉接近喷嘴的燃料质量分布，并且在 Σ 方程常数校准后，界面表面积。可以同时实现在液体和蒸汽尖端穿透和局部速度方面对喷雾远场演化的准确预测。尽管可以很好地捕获径向分布剖面，但与混合分数轴向演化相比，模型精度较低。