CH4/正癸烷混合燃料燃烧特性

为研究CH4/正癸烷混合燃料的燃烧特性及燃烧稳定性，在定容燃烧弹中测量了初始压力为0.1MPa、初始温度为420K、当量比范围为0.8~1.5和甲烷摩尔分数为0~0.8时CH4/正癸烷混合燃料的火焰扩散速度、拉伸火焰传播速度、马克斯坦长度、无拉伸火焰传播速度和层流燃烧速度等，分析了甲烷摩尔分数对马克斯坦长度及层流燃烧速度等的影响。结果表明:当量比为1.3时，随着甲烷摩尔分数的增加，火焰发展末期，前锋面由网格形胞状结构发展为光滑球面，火焰稳定性增强；甲烷摩尔分数增加导致混合燃料马克斯坦长度随当量比增加而减小的趋势变慢，实验研究范围存在临界当量比，当量比小于1.2时，甲烷摩尔分数为0.8的混合燃料燃烧稳定性较差，而当量比大于1.2时，甲烷摩尔分数为0.8的混合燃料燃烧稳定性较好；当量比在1.0~1.3范围内，甲烷摩尔分数为0.2和0.4的混合燃料层流燃烧速度较快，而在实验测量当量比范围，甲烷摩尔分数为0.8的混合燃料层流燃烧速度较慢。 

Combustion characteristics of methane/n-decane mixed fuel

In order to study the combustion characteristics and combustion stability of CH4/n-decane mixed fuel, the diffusion velocity of flame radius, the stretched flame speed, Marksein length, unstretched flame speed and laminar burning velocity of CH4/n-decane mixture were measured experimentally in a constant volume chamber at initial pressure of 0.1MPa, initial temperature of 420K, over the equivalence ratios range of 0.8－1.5 and over the methane concentration range of 0－0.8. The influences of methane concentration on Marksein length and laminar burning velocity were investigated. Results showed that at equivalence ratio of 1.3, the observed cellular structure at the end of flame propagation disappeared with the increase of methane concentration and the flame front became smooth, along with the increase of the flame stability; the decreasing trend of Marksein length with the growing equivalence ratio became slower due to the increase of methane concentration, and there was a critical equivalence ratio, with the methane concentration of 0.8 the combustion stability was poor when the equivalence ratio was smaller than 1.2 and to the contrary the combustion stability was better when the equivalence ratio was bigger than 1.2; over the equivalence ratio of 1.0－1.3 the laminar burning velocities of mixed fuel with methane concentration of 0.2 and 0.4 were faster, and over the equivalence ratios range of experiment conditions the laminar burning velocities of mixed fuel with methane concentration of 0.8 were slower.