Computations of turbulent lean premixed combustion using conditional moment closure
Computations of turbulent lean premixed combustion using conditional moment closure
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DOI：
10.1080/13647830.2013.848382
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发表时间：
2013-12-01
影响因子：
1.3
通讯作者：
Swaminathan, Nedunchezhian
中科院分区：
文献类型：
--
作者：
Amzin, Shokri;Swaminathan, Nedunchezhian
条件矩闭合 (CMC) 是一种适合预测标量的方法，例如湍流燃烧中化学时间尺度较慢的一氧化碳。尽管该方法已成功应用于非预混燃烧，但应用于稀薄预混燃烧的情况还很少。在本研究中，CMC 方法用于计算分布式燃烧状态下的先导稀薄预混燃烧。使用代数模型封闭条件标量（进度变量）的条件标量耗散率，并使用标准 k 模型对湍流进行建模。使用一阶 CMC 闭包和 GRI-3.0 化学机制来关闭条件平均反应速率，以表示甲烷氧化的化学动力学。进度变量的 PDF 是通过 Beta 函数使用假定形状获得的。将计算结果与实验测量值和早期使用传输 PDF 方法的计算结果进行比较。结果显示与实验测量结果相当一致，并且与传输 PDF 计算一致。当剪切湍流和火焰的复合效应很强时，CMC 可能需要二阶闭合。
Conditional Moment Closure (CMC) is a suitable method for predicting scalars such as carbon monoxide with slow chemical time scales in turbulent combustion. Although this method has been successfully applied to non-premixed combustion, its application to lean premixed combustion is rare. In this study the CMC method is used to compute piloted lean premixed combustion in a distributed combustion regime. The conditional scalar dissipation rate of the conditioning scalar, the progress variable, is closed using an algebraic model and turbulence is modelled using the standard k- model. The conditional mean reaction rate is closed using a first order CMC closure with the GRI-3.0 chemical mechanism to represent the chemical kinetics of methane oxidation. The PDF of the progress variable is obtained using a presumed shape with the Beta function. The computed results are compared with the experimental measurements and earlier computations using the transported PDF approach. The results show reasonable agreement with the experimental measurements and are consistent with the transported PDF computations. When the compounded effects of shear-turbulence and flame are strong, second order closures may be required for the CMC.