EULERIAN MOMENT METHODS FOR AUTOMOTIVE SPRAYS
EULERIAN MOMENT METHODS FOR AUTOMOTIVE SPRAYS
复制标题
汽车喷雾的欧拉矩方法
DOI：
10.1615/atomizspr.2015011204
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发表时间：
2015
影响因子：
1.2
通讯作者：
R. Fox
中科院分区：
文献类型：
--
作者：
Oğuz Emre;D. Kah;S. Jay;Quang;A. Velghe;S. Chaisemartin;F. Laurent;M. Massot;Q. Tran;R. Fox
为了协助工业发动机设计，3D模拟越来越多地被使用，因为它们允许评估广泛的发动机配置和运行条件，并带来对实验补充的基础物理的理解。虽然气体流动描述已经达到一定的成熟程度，但涉及注入燃烧室的液体喷气燃料的多相流描述仍然面临一些重大挑战。目前迫切需要一种既省时又能准确描述喷油器下游燃料颗粒云动力学的喷雾模型，这是预测燃烧模拟的必要前提。由于高压喷射过程后流动的高度不稳定性质，以及从分离/致密可压缩相到完全发展的具有蒸发液滴的湍流喷雾的流动形式的复杂性，欧拉-欧拉两相流动的描述被视为非常有前途的方法，可以实现混合过程的现实和预测模拟。然而，它们需要在与方程系统的更复杂的数学结构和出现在空间/时间平均方程中的非封闭项相关的物理建模和数值分析方面做出一些努力。在面临的各种挑战中，一个关键的方面是在这个框架中捕捉喷雾的多分散性。回顾了最近的发展，已经允许在喷雾建模社区的关键进展，在本文中提出。它分为四个部分。首先，介绍了汽车喷雾建模。然后介绍了发动机喷雾分散区域的描述形式，特别强调了经典拉格朗日粒子方法与欧拉方法的优缺点。第三部分介绍了欧拉高阶矩法研究尺寸多色散的动机和最新进展。最后，第四部分描述了扩展到与气相的完全双向耦合相互作用以及在CFD代码中可变几何应用中实现这种方法。利用IFP-C3D求解器计算的实际直注条件，说明了欧拉方法的应用和有效性。
To assist industrial engine design, 3D simulations are increasingly used as they allow evaluation of a wide range of engine configurations and operating conditions and bring a comprehension of the underlying physics comple-mentary to experiments. While the gaseous flow description has reached a certain level of maturity, the multiphase flow description involving the liquid jet fuel injected into the chamber still faces some major challenges. There is a pressing need for a spray model that is time efficient and accurately describes the fuel-particle cloud dynamics downstream of the injector, which is an essential prerequisite for predictive combustion simulations. Due to the highly unsteady nature of the flow following the high-pressure injection process and the complexity of the flow regimes from separated/dense compressible phases to fully developed turbulent spray with evaporating droplets, Eulerian-Eulerian descriptions of two-phase flows are seen as very promising approaches towards realistic and predictive simulations of the mixing process. However they require some effort in terms of physical modeling and numerical analysis related to the more complex mathematical structure of the system of equations and to the unclosed terms appearing in space/time-average equations. Among the various challenges faced, one critical as-pect is to capture spray polydispersity in this framework. A review of recent developments that have permitted key advances in the spray modeling community is proposed in this paper. It is divided into four parts. First, an introduction to automotive spray modeling is provided. Then the formalisms for the description of the disperse region of an engine spray are presented with particular emphasis on the pros and cons of classical Lagrangian par-ticle methods versus Eulerian approaches. The third part presents the motivation for and the recent developments of Eulerian high-order moment methods for size polydispersion. Finally, the extension to fully two-way coupled interactions with the gas phase and the implementation of such methods for variable-geometry applications in CFD codes is described in the fourth part. Using realistic direct injection conditions computed with the IFP-C3D solver, the application and efficiency of Eulerian approaches is illustrated.