汽油在多孔介质中燃烧的数值模拟

Combustion Characteristics of the Gasoline in Porous Burner

对汽油在典型多孔介质燃烧器中的燃烧特性进行了数值模拟,引入汽油详细反应热力学数据,运用平均混合分数/概率密度函数PDF的非预混燃烧模型分析了多孔介质中汽油燃烧的温度和污染物分布特性。结果表明,多孔介质燃烧器内高温区域分布较广,温度分布相对均匀。温度沿中心轴线先升至最高,后降低,最后逐渐升高形成稳定高温区;沿径向方向温度梯度分布明显,燃烧温度从中心向壁面逐渐降低;CO和CO_2摩尔分数分布与燃烧温度分布相关,CO摩尔分数在火焰中心区域分布最高,随着扩散混合过程的深入逐渐降低;CO_2摩尔分数在燃烧器上游率先出现峰值后,略有降低,随着扩散混合过程的深入逐渐升高。

The combustion characteristics of gasoline were numerically simulated in a typical porous burner.Based on importing the thermodynamic data of the detailed reaction of the gasoline,the distribution characteristics of temperature were analyzed by the non-premixed combustion model with the probability density function method(PDF)of mixture fraction.The results show that the high temperature region in porous burner is widely distributed,and the temperature distribution is relatively uniform.Firstly,the combustion temperature increases to the maximum value,and decrease slightly along the center axis,and then increases gradually to form a stable high temperature zone.Radial direction temperature gradient distribution is obvious,and the combustion temperature from the center to the wall gradually reduced;Mole fraction distribution of both CO and CO 2 is associated with that of the temperature.The maximum value of the CO mole fraction distribution appears on the central region of the flame,and it gradually decreases with the further diffusion and mixing;the CO 2 peak first appeared in the upstream,and decreases slightly in the central zone of the flame,then increases with the further diffusion and mixing.