Partially premixed reacting acetone spray using LES and FGM tabulated chemistry
Partially premixed reacting acetone spray using LES and FGM tabulated chemistry
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DOI：
10.1016/j.combustflame.2012.03.009
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发表时间：
2012-08
影响因子：
4.4
通讯作者：
M. Chrigui;J. Gounder;A. Sadiki;A. Masri;J. Janicka
中科院分区：
文献类型：
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作者：
M. Chrigui;J. Gounder;A. Sadiki;A. Masri;J. Janicka
采用欧拉-拉格朗日方法对稀相喷雾-空气反应两相流进行了大涡模拟。该方法包括一个完整的双向耦合，其中相位属性和喷雾源项在每个耦合时间步长内在两个相位之间互换。为了实现亚网格尺度封闭用于LES的载体相的过滤方程，Smagorinsky模型与动态程序应用于流场，而涡扩散率的方法是用于标量通量。液滴的相变是使用非平衡蒸发模型捕获。蒸发的液滴使用Langragian程序跟踪。它们以多分散的方式注入，并在时间依赖的边界条件下生成。燃烧过程由反应进程变量和混合气分数以及它们在小火焰生成流形方法中的方差来描述。这项工作的最终目标是评估这种基于LES的喷雾模块在这里开发检索的喷雾流动和燃烧性能的配置下研究的能力。该配置包括一个喷雾射流发出到一个试点火焰和一个共同流动的大气中，液滴遍历一个预蒸发的距离，并释放其质量的一部分，然后到达燃烧区。因此，喷雾预蒸发将燃烧状态从扩散转变为部分预混合。所使用的燃料是液体丙酮，这是由一个详细的反应机理，包括84物种和409个基元反应。对不同工况下建立的一系列喷雾进行了研究、分析和比较。分析可以深入了解正在进行的过程。比较包括排气温度，液滴速度和相应的波动，液滴平均直径和喷雾体积流量在不同的距离从出口平面。据报道，总体一致。
Large Eddy Simulations of dilute spray-air reacting two phase flow are performed following an Eulerian–Lagrangian approach. The method includes a full two-way coupling in which phase properties and spray source terms are interchanging between the two phases within each coupling time step. To achieve sub-grid scale closures in the filtered equations used for LES of the carrier phase, the Smagorinsky model with dynamic procedure is applied for the flow field while an eddy diffusivity approach is used for the scalar fluxes. The phase transition of droplets is captured using a non-equilibrium evaporation model. The evaporating droplets are tracked using a Langragian procedure. They are injected in a polydisperse manner and generated in time dependent boundary conditions. The combustion is described by a reaction progress variable and a mixture fraction as well as their variances in the line of the Flamelet Generated Manifold method. The ultimate objective of this work is to appraise the ability of this LES-based spray module developed here to retrieve the spray flow and combustion properties of the configuration under study. The configuration consists of a spray jet issued into a pilot flame and a co-flowing atmospheric air in which droplets traverse a pre-evaporation distance and release part of their mass before reaching the combustion zone. Thereby the spray pre-evaporation turns the combustion regime from diffusion to partially premixed. The fuel used is liquid acetone, which is modeled by a detailed reaction mechanism including 84 species and 409 elementary reactions. A series of spray established at different operating conditions are investigated, analyzed and compared. Analysis allows to gain a deep insight into the process ongoing. Comparisons include exhaust gas temperature, droplet velocities and corresponding fluctuations, droplet mean diameters and spray volume flux at different distances from the exit planes. An overall good agreement is reported.