The Modeling of Fuel Mass Fraction Variance Transport in Turbulent Stratified Flames: A Direct Numerical Simulation Study
The Modeling of Fuel Mass Fraction Variance Transport in Turbulent Stratified Flames: A Direct Numerical Simulation Study
复制标题
湍流分层火焰中燃料质量分数方差传输的建模：直接数值模拟研究
DOI：
10.1080/10407782.2010.497332
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
N. Chakraborty
中科院分区：
文献类型：
--
作者：
S. Malkeson;N. Chakraborty
对全局当量比 ⟨φ⟩ = 0.7 和 ⟨φ⟩ = 1.0 的统计平面湍流分层火焰进行了基于三维可压缩简化化学的直接数值模拟 (DNS)，以分析 Favre 燃料质量分数波动方差传递的统计行为（其中 、 和 分别是雷诺平均值、Favre 平均值和一般量 q 的 Favre 波动，其中ρ 是气体密度）在雷诺平均纳维-斯托克斯 (RANS) 模拟中。人们发现代数表达式不足以预测低 Damköhler 数燃烧，并且可能需要求解 的传输方程。详细分析了输运方程的统计行为和未封闭项（即源自湍流输运 T 1 、反应速率 T 3 和分子耗散 D 2 的项）。研究发现，在所有情况下，T 3 和D 2 仍然是输运的主要贡献者，而T 1 在⟨φ⟩ = 1.0 情况下的贡献仍然很小，但在⟨φ⟩ = 0.7 情况下发挥着更重要的作用。通过先验 DNS 分析，详细解决了 T 1、T 3 和 D 2 的建模问题。 T 1 的模型已确定，它与 DNS 数据具有令人满意的一致性。 T 3 和 D 2 模型最初是针对高 Damköhler 数火焰提出的，现已在 RANS 模拟的背景下针对低 Damköhler 燃烧进行了修改，并且发现修改后模型的预测与从 DNS 数据中提取的相应量非常一致。
Three-dimensional compressible simplified chemistry-based direct numerical simulations (DNS) of statistically planar turbulent stratified flames at global equivalence ratios ⟨φ⟩ = 0.7 and ⟨φ⟩ = 1.0 have been carried out to analyze the statistical behavior of the transport of the variance of the Favre fuel mass fraction fluctuations (where , and are Reynolds average, Favre mean, and Favre fluctuation of a general quantity q where ρ is the gas density) in the context of Reynolds-averaged Navier-Stokes (RANS) simulations. It has been found that algebraic expressions are inadequate for predicting in low Damköhler number combustion, and a transport equation for may need to be solved. The statistical behaviors of and the unclosed terms of the transport equation (i.e., the terms originating from turbulent transport T 1 , reaction rate T 3 , and molecular dissipation D 2) have been analyzed in detail. It has been found, that T 3 and D 2 remain leading order contributors to the transport in all cases, whereas, the contribution of T 1 remains small in ⟨φ⟩ = 1.0 cases, but plays a more important role in ⟨φ⟩ = 0.7 cases. Through an a-priori DNS analysis, the modeling of T 1, T 3, and D 2 has been addressed in detail. A model has been identified for T 1, which provides satisfactory agreement with the DNS data. The models for T 3 and D 2, which were originally proposed for high Damköhler number flames, have been modified for low Damköhler combustion in the context of RANS simulations, and the predictions of the modified models are found to be in good agreement with the corresponding quantities extracted from the DNS data.
影响因子：
4.6
作者：
N. Chakraborty;N. Swaminathan
通讯作者：
N. Chakraborty;N. Swaminathan