A posteriori testing of the flame surface density transport equation for LES
A posteriori testing of the flame surface density transport equation for LES
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DOI：
10.1080/13647830.2013.848383
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发表时间：
2014-01
影响因子：
1.3
通讯作者：
T. Ma;O. Stein;N. Chakraborty;Achim Kempf
中科院分区：
文献类型：
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作者：
T. Ma;O. Stein;N. Chakraborty;Achim Kempf
大涡模拟（LES）的火焰表面密度（FSD）模型的实施和测试的规范配置和实际的海崖体稳定燃烧器，比较常见的代数封闭与传输方程封闭的湍流预混燃烧的背景下。运输方法预计将产生优势代数封闭，作为平衡的子网格生产和破坏的FSD不再强制执行和解决过程中的应变，传播和曲率明确占。这些优点可能具有提高在燃烧不稳定的情况下或在火焰随时间遇到渐进扰动的情况下捕获大规模不稳定火焰传播的能力的潜力。在风洞湍流中传播的湍流火焰的初步研究表明，代数火焰表面密度（FSDA）的方法可以预测一个过度起皱的火焰细网格条件下，潜在的增加反应物的消耗率人为更高的水平。相比之下，火焰表面密度传输（FSDT）封闭预测一个平滑的火焰前锋，避免了人工火焰尖点的形成时，网格细化。五个FSDA模型和FSDT方法，然后应用到LES的沃尔沃钻机。预测的平均速度被认为是相对不敏感的FSDT和FSDA的方法的使用，而温度预测表现出明显的差异，不同的配方。FSDT方法产生非常相似的温度预测的两个测试FSDA模型，定量捕获的平均温度。网格细化被发现，以提高平均火焰蔓延的FSDT预测。总体而言，本文表明，显然复杂的FSD传输方程的方法可以实现和应用到现实的，强烈的皱纹火焰，取得了很好的成功，并开辟了进一步的工作，以改善模型和整体FSDT方法的领域。
Flame Surface Density (FSD) models for Large Eddy Simulation (LES) are implemented and tested for a canonical configuration and a practical bluff body stabilised burner, comparing common algebraic closures with a transport equation closure in the context of turbulent premixed combustion. The transported method is expected to yield advantages over algebraic closures, as the equilibrium of subgrid production and destruction of FSD is no longer enforced and resolved processes of strain, propagation and curvature are explicitly accounted for. These advantages might have the potential to improve the ability to capture large-scale unsteady flame propagation in situations with combustion instabilities or situations where the flame encounters progressive wrinkling with time. The initial study of a propagating turbulent flame in wind-tunnel turbulence shows that the Algebraic Flame Surface Density (FSDA) method can predict an excessively wrinkled flame under fine grid conditions, potentially increasing the consumption rate of reactants to artificially higher levels. In contrast, the Flame Surface Density Transport (FSDT) closure predicts a smooth flame front and avoids the formation of artificial flame cusps when the grid is refined. Five FSDA models and the FSDT approach are then applied to the LES of the Volvo Rig. The predicted mean velocities are found to be relatively insensitive to the use of the FSDT and FSDA approaches, whereas temperature predictions exhibit appreciable differences for different formulations. The FSDT approach yields very similar temperature predictions to two of the tested FSDA models, quantitatively capturing the mean temperature. Grid refinement is found to improve the FSDT predictions of the mean flame spread. Overall, the paper demonstrates that the apparently complicated FSD transport equation approach can be implemented and applied to realistic, strongly wrinkled flames with good success, and opens up the field for further work to improve the models and the overall FSDT approach.