A flamelet model for turbulent diffusion combustion in supersonic flow
A flamelet model for turbulent diffusion combustion in supersonic flow
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DOI：
10.1007/s11431-010-4169-z
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发表时间：
2010-11
期刊：
影响因子：
--
通讯作者：
Zhenxun Gao;Chunhian Lee
中科院分区：
文献类型：
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作者：
Zhenxun Gao;Chunhian Lee
为了建立适用于超声速流动的湍流扩散燃烧模型，提出了将火焰面模型推广到超声速流动的物理依据，并采用火焰面模型对轴对称超声速射流产生的氢气/空气扩散燃烧流场进行了数值模拟。利用实验数据，对火焰面模型中的标量耗散系数进行了修正。将修正后的火焰面模型的计算结果与实验结果进行了比较，结果表明修正后的火焰面模型具有较好的精度。基于数值计算结果和火焰面理论，首次研究了湍流脉动对平均状态方程和化学反应速率的影响机理。结果表明，组分质量分数与温度的波动关联对平均气体状态方程的影响不大，温度波动降低了H2O生成量，但影响不大，组分质量分数的波动增加了靠近氧化剂区域的H2O生成量，而减少了其他区域的H2O生成量;组分质量分数与温度的波动相关性大大降低了H2O的生成量。
In order to develop a turbulent diffusion combustion model for supersonic flow, the physical argument of the extension of the flamelet model to supersonic flow was presented, and the flow field of a hydrogen/air diffusion combustion generated by axisymmetric supersonic jets was numerically simulated by employing the flamelet model. Using the experimental data, value of the model coefficient of scalar dissipation in the flamelet model was revised specifically for supersonic flow. The computational results of the modified flamelet model were compared with the experimental results, and it was indicated that the precision of the modified flamelet model was satisfying. Based on the numerical results and flamelet theory, the influence mechanisms of turbulence fluctuation on the average state equation and chemical reaction rate were studied for the first time. It was found that the fluctuation correlation of species mass fractions and temperature has little effect on the averaged gas state equation; the temperature fluctuation decreases the product of H2O, but its effect is small; the fluctuation of species mass fractions increases the product of H2O in the region close to oxidizer while decreases the product of H2O in other regions; the fluctuation correlation of species mass fractions and temperature largely decreases the product of H2O.