Transported PDF modeling of high-Reynolds-number premixed turbulent flames
Transported PDF modeling of high-Reynolds-number premixed turbulent flames
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DOI：
10.1016/j.combustflame.2005.12.015
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发表时间：
2006-05
影响因子：
4.4
通讯作者：
R. Lindstedt;E. Váos
中科院分区：
文献类型：
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作者：
R. Lindstedt;E. Váos
传输PDF的方法，关闭在联合组成焓水平，适用于模型预混湍流火焰在很宽的雷诺数范围内。研究的最初目的是建立封闭近似的标量耗散率湍流波动和预测的湍流燃烧速度之间的关系的影响。考虑的情况下，化学计量的甲烷-空气火焰与化学源项提取的详细化学模拟相应的无应变层流火焰的功能。随后将传输PDF方法与具有142个反应和14个溶解和15个稳态物种的系统性简化的C/H/O机制相结合，并应用于Chen等人实验研究的先导预混化学计量甲烷-空气火焰[Combust. Flame 107（1996）223-226]。这里考虑的情况的特点是Re= 24，200（火焰F3）和52，500（火焰F1），达姆克勒数接近1。研究了时间尺度比（2 μ C/8）和燃烧器热损失变化的影响，沿着扩展的标量耗散率代数关系的影响，该关系解释了小尺度特性。与实验数据的比较表明，修改后的Curl的模型和扩展标量耗散率封闭产生的湍流燃烧速度与测量密切一致。该研究进一步表明，在联合标量水平结合全面的化学封闭有可能重现预混湍流火焰的详细化学结构。边界条件和全面的标量统计，包括标量耗散率的重要性，也强调了研究。
The transported PDF approach, closed at the joint composition–enthalpy level, is applied to model premixed turbulent flames at a wide range of Reynolds numbers. The initial aim of the study is to establish the impact of closure approximations for the scalar dissipation rate upon the relationship between turbulence fluctuations and predicted turbulent burning velocities. The cases considered feature stoichiometric methane–air flames with the chemical source term extracted from a detailed chemistry simulation of the corresponding unstrained laminar flame. The transported PDF approach is subsequently combined with a systematically reduced C/H/O mechanism featuring 142 reactions and 14 solved and 15 steady-state species and applied to piloted premixed stoichiometric methane–air flames investigated experimentally by Chen et al. [Combust. Flame 107 (1996) 223–226]. The cases considered here feature Re=24,200 (flame F3) and 52,500 (flame F1) and Damköhler numbers approaching unity. The effects of variations in the time-scale ratio (2⩽Cϕ⩽8) and heat losses to the burner were investigated, along with the impact of an extended algebraic relationship for the scalar dissipation rate that accounts for small-scale properties. Comparisons with experimental data show that the modified Curl's model and the extended scalar dissipation-rate closure produce turbulent burning velocities in close agreement with measurements. The study further indicates that a closure at the joint scalar level combined with comprehensive chemistry has the potential to reproduce the detailed chemical structure of premixed turbulent flames. The importance of boundary conditions and comprehensive scalar statistics, including the scalar dissipation rate, is also emphasized by the study.