PDF modelling of turbulent non-premixed combustion with detailed chemistry
PDF modelling of turbulent non-premixed combustion with detailed chemistry
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具有详细化学成分的湍流非预混燃烧的 PDF 建模
DOI：
10.1016/j.ces.2004.05.015
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发表时间：
2004
影响因子：
4.7
通讯作者：
Yiliang Chen
中科院分区：
文献类型：
--
作者：
Haifeng Wang;Yiliang Chen
虽然概率密度函数（PDF）方法在湍流燃烧问题中精确处理化学反应的显著优势，但详细的化学机理（例如，GRI机制）由于PDF方法的计算量太大，至今尚未在实际计算中实现。在这项工作中，一个详细的机制（GRI-Mech 3.0，由53个物种和325个元素反应）首次纳入湍流非预混射流火焰（Sandia Flame D）的PDF计算。流动以边界层形式表示。采用联合合成PDF封闭层，结合多时间尺度（MTS）k-ε湍流模型封闭湍流输运项。分子混合过程采用欧氏最小生成树（埃姆斯特）混合模型。湍流方程采用空间推进算法求解，PDF发展方程采用基于节点的Monte Carlo粒子方法求解。化学反应源项直接积分。预测和测量之间进行了广泛的比较，其中包括径向分布的平均值和均方根（均方根），条件平均值，标量和条件PDF分布等的散点图的火焰结构是很好地代表了目前的计算，包括中间物种（如CO和H2）的质量分数，污染物NO排放和本地消光。
Although the significant advantage for the probability density function (PDF) methods of the exact treatment of chemical reactions in turbulent combustion problems, a detailed chemistry mechanism (e.g., the GRI mechanism) has not been implemented in the practical calculations by now due to the prohibitive computation of PDF methods. In this work, a detailed mechanism (GRI-Mech 3.0, consisting of 53 species and 325 elemental reactions) is firstly incorporated into the PDF calculation of a turbulent non-premixed jet flame (Sandia Flame D). The flow is formulated in the boundary layer form. The joint composition PDF closure level is applied and a multiple-time-scale (MTS) k–ε turbulence model is combined for the closure of turbulent transport terms. The molecular mixing process is modelled by the Euclidean minimum spanning tree (EMST) mixing model. The solutions are obtained by using the space marching algorithm for turbulence equations and node-based Monte Carlo particle method for PDF evolution equation. The chemical reaction source terms are integrated directly. Extensive comparisons between the predictions and the measurements are made, which involve radial profiles of mean and rms (root mean square), conditional mean, scatter plots of scalars and conditional PDF distribution etc. The flame structures are well represented by the present calculation, including intermediate species (e.g. CO and H2) mass fractions, pollutant NO emission and local extinction.