The effect of mixing models in PDF calculations of piloted jet flames
The effect of mixing models in PDF calculations of piloted jet flames
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DOI：
10.1016/j.proci.2006.08.052
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发表时间：
2007-01-01
影响因子：
3.4
通讯作者：
Pope, Stephen B.
中科院分区：
文献类型：
--
作者：
Cao, Renfeng Richard;Wang, Haifeng;Pope, Stephen B.
对于包含显著湍流-化学相互作用的湍流火焰，PDF模型计算的准确性取决于化学的准确表示和混合模型(包括混合模型常数C-Phi的值)。在最近的工作中，曹和波普证明了使用GR13.0机制和Emst混合模型(C-Phi=1.5)可以精确计算Barlow和Frank引导的喷射火焰D、E和F。为了考察三种混合模型(EMST、IEM和MC)的性能以及它们对C-Phi指定值的依赖关系，本文用GRI3.0进行了进一步的PDF模型计算。结果表明，三种模型都能产生与实验观测相当的局部消光水平(由燃烧指数量化)，但这是在IEM的C-Phi=3.3和MC的C-Phi=3.8(相比之下，Emst的C-Phi=1.5)下实现的。然而，在这些用IEM和MC进行的计算中，混合分数的方差被严重低估：只有Emst模型能够准确地计算观察到的燃烧指数和混合分数方差。这项研究是第一次对巴洛和弗兰克火焰中的混合模型进行比较研究，其结果与之前的观察结果有关。(C)2006年，燃烧研究所。爱思唯尔公司出版，版权所有。
For turbulent flames containing significant turbulence-chemistry interactions, the accuracy of PDF model calculations depends on the accurate representation of the chemistry and on the mixing model (including the value of the mixing-model constant, C-phi). In recent work, Cao and Pope demonstrated that accurate calculations of the Barlow and Frank piloted jet flames D, E and F are achieved using the GR13.0 mechanism and the EMST mixing model (with C-phi = 1.5). In the present paper, further PDF model calculations (using GRI3.0) are performed in order to investigate the performance of three mixing models (EMST, IEM and MC) and their dependence on the specified value of C-phi. It is shown that all three models are capable of yielding levels of local extinction (quantified by a burning index) comparable to the experimental observations, but this is achieved using C-phi = 3.3 for IEM, and C-phi = 3.8 for MC (compared to C-phi = 1.5 for EMST). However, in these calculations with IEM and MC, the mixture fraction variance is significantly underpredicted: only the EMST model is capable of calculating accurately both the observed burning indexes and the mixture fraction variance. The findings of this study, the first comparative study of mixing models in the Barlow and Frank flames, are related to previous observations. (C) 2006 The Combustion Institute. Published by Elsevier Inc. All rights reserved.