氢、碳氢燃料对向扩散火焰

对氢、正烷烃碳氢燃料与氧的对向扩散火焰，其中正烷烃包含了在工业用燃料中广泛应用的C_nH_2n+2正烷烃CH₄～C1₆H₃₄，对这些燃料的火焰结构进行了分析和比较，系统地分析了压力和拉伸率对火焰行为和热释放率等的影响，其中包含了2115个组分8157个可逆反应．研究结果表明，所有燃料的火焰厚度和热释放率与压力和拉伸率的乘积的平方根成线性关系．在相同工况下，氢的火焰厚度总是大于所有的碳氢燃料，而CH₄～C1₆H₃₄所有的碳氢燃料在相同工况下总是具有几乎相同的燃烧温度分布、燃烧产物分布、火焰厚度和热释放率，该结果表明由这些碳氢燃料组成的混合燃料具有同样的火焰特性.

Modeling Study of Hydrogen/Oxygen and n-alkane/Oxygen Counterflow Diffusion Flames

A comprehensive analysis of hydrogen/oxygen and hydrocarbon/oxygen counterflow diffu-sion flames has been conducted using corresponding detailed reaction mechanisms. The hydrocarbon fuels contain n-alkanes from CH₄ to C₁₆H₃₄. The basic diffusion flame struc-tures are demonstrated, analyzed, and compared. The effects of pressure, and strain rate on the flame behavior and energy-release rate for each fuel are examined systematically. The de-tailed chemical kinetic reaction mechanisms from Lawrence Livermore National Laboratory(LLNL) are employed, and the largest one of them contains 2115 species and 8157 reversible reactions. The results indicate for all of the fuels the flame thickness and heat release rate correlate well with the square root of the pressure multiplied by the strain rate. Under the condition of any strain rate and pressure, H₂ has thicker flame than hydrocarbons, while the hydrocarbons have the similar temperature and main products distributions and almost have the same flame thickness and heat release rate. The result indicates that the fuels composed with these hydrocarbons will still have the same flame properties as any pure n-alkane fuel.