Mixture fraction field in a turbulent nonreacting propane jet
Mixture fraction field in a turbulent nonreacting propane jet
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湍流非反应丙烷射流中的混合分数场
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
R. Dibble
中科院分区：
文献类型：
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作者：
R. Schefer;R. Dibble
本文用激光瑞利散射法测量了丙烷湍流无反应喷流在空气中的时间和空间分辨混合物分数。测量的目的是为了更好地了解湍流变密度射流中的流动结构和混合过程，其中湍流混合已与高放热反应射流中的化学放热效应解耦。测量结果产生的混合物分数的概率密度分布，从中计算的平均值，高阶矩，和双折射率。分析了瑞利信号的时程，得到其功率谱和自相关函数。与其他恒定和变密度湍流射流的结果进行了比较，并讨论了所观察到的差异。I.引言湍流反应气流数值模型的发展主要基于非反应、等密度气流的子模型。由于湍流混合和燃烧放热之间复杂的相互作用，这些子模型的验证往往是困难的。以前的证据表明，使用基于等温或非反应紊流的子模型在反应紊流中可能是无效的。湍流、变密度、非反应射流提供了一种复杂的艾德流动情况，其中保持了变密度的复杂性，而没有湍流混合和化学放热之间的复杂耦合。因此，变密度对湍流的影响可以从燃烧化学中分离出来.非反应变密度流是非反应等密度流和反应湍流流之间的逻辑桥梁，而建立反应湍流流的数据库是发展湍流反应流数值模式的必要条件。
Time- and space-resolved mixture fraction measurements have been made throughout a turbulent nonreacting propane jet issuing into coe owing air using laser Rayleigh scattering. The objective of the measurements has been to obtain a better understanding of the e ow structure and mixing process in turbulent variable-density jets where turbulent mixing has been decoupled from the effects of chemical heat release found in highly exothermic reacting jets. The measurements yield probability density distributions of the mixture fraction, from which the means, higher moments, and intermittency are calculated. Time histories of the Rayleigh signal are analyzed to obtain the power spectra and autocorrelations. Comparisons are made with results for other constant- and variable-density turbulent jets, and the observed differences are discussed. I. Introduction T HE development of numerical models for turbulent reacting e owsisbasedlargelyonsubmodelsdevelopedfornonreacting, constant-density e ows. Verie cation of these submodels is often dife cult due to the complex interaction between turbulent mixing and combustion heat release. Previous evidence indicates that the use of submodels based on isothermal or nonreacting turbulent e ows may not be valid in reacting e ows. 1i 3 The turbulent, variable-density, nonreacting jet provides a simplie ed e ow situation in which the complexity of variable density remains without the complex coupling between turbulent mixing and chemical heat release. Thus the effects of variable density on turbulence can be isolated from combustion chemistry. Nonreacting, variable-density e ows form a logical bridge between nonreacting constant-density and reacting turbulent e ows in which the development of a database is necessary to the development of numerical models for turbulent reacting e ows.