Modeling stratified flames with and without shear using multiple mapping conditioning
Modeling stratified flames with and without shear using multiple mapping conditioning
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DOI：
10.1016/j.proci.2018.07.033
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发表时间：
2019
影响因子：
3.4
通讯作者：
C. Straub;A. Kronenburg;O. Stein;R. Barlow;D. Geyer
中科院分区：
文献类型：
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作者：
C. Straub;A. Kronenburg;O. Stein;R. Barlow;D. Geyer
一个随机稀疏粒子的方法耦合到人工增厚火焰（ATF）模型的大涡模拟（LES）预测一系列的湍流预混分层火焰和不剪切和分层。加厚的反应进程变量作为参考变量的多重映射条件（MMC）混合模型，模拟湍流混合的随机颗粒。MMC的关键特征是当颗粒对混合时在该参考空间中强制局部性，并且防止穿过火焰前缘的燃烧和未燃烧流体的非物理混合。我们将MMC-ATF应用于一系列湍流分层火焰中的三种火焰，并通过与实验数据的比较来验证该方法。与先前公布的相同火焰的数据相比，新的测量方法具有更高的准确性，这是由于更好的信噪比和不太容易发生光束转向的设置。所有的火焰位置预测的LES-ATF的方法和MMC颗粒的统计分析表明，MMC保留小火焰的行为在实验中显示出低分散的小火焰的解决方案周围的区域。预测（本地）的火焰解决方案的偏差是可比的测量中观察到的偏差和火焰结构中的变化，由于分层和剪切的差异，合理地很好地捕获的方法。
A stochastic sparse particle approach is coupled with an artificial thickening flame (ATF) model for large eddy simulations (LES) to predict a series of turbulent premixed-stratified flames with and without shear and stratification. The thickened reaction progress variable serves as reference variable for the multiple mapping conditioning (MMC) mixing model which emulates turbulent mixing of the stochastic particles. The key feature of MMC is to enforce localness in this reference space when particle pairs are mixed and prevents unphysical mixing of burnt and unburnt fluid across the flame front. We apply MMC-ATF to three flames of a series of turbulent stratified flames and validate the method by comparison with experimental data. The new measurements feature increased accuracy in comparison to previously published data of the same flames due to a better signal-to-noise ratio and a setup which is less prone to beam steering. All flame locations are well predicted by the LES-ATF approach and an analysis of the MMC particle statistics demonstrates that MMC preserves the flamelet-like behaviour in regions where the experiments show low scatter around the flamelet solution. Predicted (local) deviations from the flamelet-solution are comparable to deviations observed in the measurements and variations in the flame structure due to differences in stratification and shear are reasonably well captured by the method.