【摘要】 在定容燃烧弹内研究了初始压力为0.5 MPa时,不同初始温度和燃空当量比下二甲醚—空气混合气预混层流火焰的层流燃烧速率和马克斯坦长度,分析了火焰拉伸对火焰传播速率的影响。基于容弹燃烧的双区模型计算了预混层流燃烧的燃烧特性参数。结果表明:随着初始温度的增加,二甲醚—空气预混合气的无拉伸火焰传播速率和无拉伸层流燃烧率增加;对于给定的初始温度,在化学当量比偏浓混合气一侧存在一个层流燃烧速度的峰值;随初始温度和当量比增加,马克斯坦长度值减小,火焰前锋面的不稳定性增加;最大燃烧压力随初始温度的增加而下降,压力升高率随初始温度的增加而降低。更多还原

【Abstract】 Laminar burning velocity and the Markstein length of the dimethyl ether-air premixed mixtures were measured in a constant volume bomb under different equivalence ratios and initial temperatures at initial pressure of 0.5 MPa.The effect of flame stretch on the flame speed was analyzed and a two-zone model was used to analyze the combustion characteristics of the premixed combustion.The results showed that the laminar burning velocity was increased with the increase of the initial temperature and there exists a maximum value of the laminar burning velocity for the mixture slightly richer than the stoichiometric mixture for a given initial pressure and temperature.The Markstein length was decreased with the increase of equivalence ratio and initial temperature,indicating an increase of instability of the flame front with the increase of the equivalence ratio and initial temperature.Maximum combustion pressure was decreased with the increase of the initial temperature while the rate of pressure rise was increased with the increase of the initial temperature.更多还原