A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments
A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments
复制标题
基于直接数值模拟和实验的提升式柴油机火焰稳定机理概念模型
DOI：
10.1016/j.combustflame.2018.12.007
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发表时间：
2019-03
影响因子：
4.4
通讯作者：
Fabien Tagliante;T. Poinsot;L. Pickett;P. Pepiot;L. Malbec;G. Bruneaux;C. Angelberger
中科院分区：
文献类型：
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作者：
Fabien Tagliante;T. Poinsot;L. Pickett;P. Pepiot;L. Malbec;G. Bruneaux;C. Angelberger
这项工作提出了一个稳定的扩散火焰的分析所产生的燃料喷射到热空气中，发现在柴油发动机。它是基于实验观察，并使用一个专门的直接数值模拟（DNS）的方法来构建一个数值设置，再现实验获得的点火功能。然后使用所得到的DNS数据来分类和分析允许火焰从燃料喷射器稳定在一定离地长度（LOL）的事件。DNS和实验都表明，这种稳定是间歇性的：火焰元素首先自燃，然后对流下游，直到另一个突然自燃事件发生更接近燃料喷射器。火焰拓扑结构与这些事件进行了详细讨论，使用DNS的结果，并提出了一个概念模型，总结了观察。结果表明，火焰稳定机理主要是自燃。然而，在燃料射流的外围也观察到多个反应区拓扑结构，例如三重火焰，通过填充位于外围的高温燃烧气体储存器来帮助火焰稳定，这触发自动点火。
This work presents an analysis of the stabilization of diffusion flames created by the injection of fuel into hot air, as found in Diesel engines. It is based on experimental observations and uses a dedicated Direct Numerical Simulation (DNS) approach to construct a numerical setup, which reproduces the ignition features obtained experimentally. The resulting DNS data are then used to classify and analyze the events that allow the flame to stabilize at a certain Lift-Off Length (LOL) from the fuel injector. Both DNS and experiments reveal that this stabilization is intermittent: flame elements first auto-ignite before being convected downstream until another sudden auto-ignition event occurs closer to the fuel injector. The flame topologies associated to such events are discussed in detail using the DNS results, and a conceptual model summarizing the observation made is proposed. Results show that the main flame stabilization mechanism is auto-ignition. However, multiple reaction zone topologies, such as triple flames, are also observed at the periphery of the fuel jet helping the flame to stabilize by filling high-temperature burnt gases reservoirs localized at the periphery, which trigger auto-ignitions.