Numerical Study on Flammability Limit of CO,CH4 Mixed Fuel
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摘要: 针对CO、CH4混合燃料,以层流对冲扩散火焰为对象,利用详细反应机理(GRI-Mech 3.0)模拟计算CO、CH4混合火焰的熄火极限特性,解明了最高火焰温度(也称峰值火焰温度)随拉伸率和CO摩尔分数(αCO)的变化规律,分析了拉伸率和燃料成分的变化对火焰熄火极限的影响,进而着重讨论了造成这种影响的各种因素,以及这些因素在燃烧过程中各自产生的对温度的影响.研究发现:火焰温度随着拉伸率的增长而明显下降;随着αCO的增大,OH的生成速率降低,火焰温度降低,燃烧强度也随之减小.Abstract: In this paper,numerical investigations on flammability limit of axisymmetric count-flow laminar diffusion flames of CO,CH4 mixed fuel were conducted by using the detailed kinetic mechanism(GRI-Mech 3.0).The peak flame temperatures of the flames with different mole fractions of CO and strain rates were obtained,and the influence of the variation of αCO and strain rates on flammability limit was understood.Then the effects of main factors on flame characteristics were studied.It is found that the flame temperature decreases obviously with increasing strain rate.The formation rate of OH is reducing along with the increasing αCO,which leads to the decrease of the flame temperature,as well as the combustion intensity.
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