湍流扩散火焰局部熄火和再燃现象的PDF模拟

对一个值班湍流CH4／O2／N2射流扩散火焰(Sandia Flame D)进行了数值模拟研究．所采用的数学物理模型包括双尺度的k—ε湍流模型，标量联合的概率密度函数(PDF)输运方程方法，甲烷氧化的ARM简化化学反应机理(包含16种组分，12步总包反应)和欧几里德最小生成树(EMST)小尺度混合模型．将计算结果和实验数据进行了比较，不仅对于平均量，对于标量的散点分布和条件概率密度分布也是如此．计算结果表明文中采用的模型不仅能够预测宏观的火焰结构，而且预测了湍流燃烧中复杂的局部熄火和再燃过程．

PDF Modeling of Local Extinction and Re-ignition Within Turbulent Non-Premixed Flame

A piloted CH4/O2/N2 turbulent jet non-premixed flame(Sandia flame D)is numerically investigated. The summary of the adopted models contains a two-scale k - ε turbulence model, the scalar joint probability density function (PDF) transport equation approach, the augmented reduced mechanism(ARM)for methane oxidation (consisting of 16 species and 12 lumped reaction steps), the Euclidean minimum spanning tree (EMST)small scale mixing model etc. The agreements between the numerical results and the experimental data are good, including the scatter plots and conditional PDFs of scalars as well as the scalar averages.The numerical results indicate that the present models are not only able to represent the macro flame structure accurately, but also can successfully predict the complicated local extinction and re-ignition processes in the turbulent combustion.