二甲醚—空气混合气层流燃烧速度的测定

Measurement of Laminar Burning Velocity of Dimethyl Ether-Air Mixtures

在定容燃烧弹中利用高速纹影摄像法系统地研究了不同燃空当量比和初始压力下二甲醚—空气混合气的层流燃烧特性。利用球形扩散火焰理论分析纹影照片,获得了不同初始压力和当量比下的二甲醚—空气混合气层流燃烧速率。结果表明:随着初始压力的增大,层流燃烧速率显著减小,层流燃烧速率的峰值向浓混合气侧偏移。拉伸层流燃烧速率随拉伸率的增加而增加,拉伸层流质量燃烧速率随拉伸率的增加而减小。根据球形扩散火焰模型得到混合气的马克斯坦长度值表明:在各初始压力下,随着当量比的增加,二甲醚—空气混合气的马克斯坦长度值逐渐减小,火焰前锋面的不稳定性增加。

Measurement of laminar burning velocity of dimethyl ether-air mixtures was made under different initial pressures and equivalence ratios using a constant volume vessel and high-speed schlieren photography. The results show that the laminar burning velocity decreases with the increase of initial pressure and the maximum laminar burning velocity shifts to the rich mixture region at high initial pressure. The stretched laminar burning velocity increases with the increase of stretch rate while the stretched mass burning velocity decreases with the increase of stretch rate. Markstein length decreases with the increase of equivalence ratio, indicating the increase of flame instability in flame front with the increase of equivalence ratio.