二甲醚-氢气-空气混合气预混燃烧的实验研究

Experimental Study on Premixed Combustion of Dimethyl Ether-Hydrogen-Air Mixtures

在定容燃烧弹中,研究了不同燃空当量比、掺氢比和初始压力下的二甲醚-氢气-空气预混合气的一系列层流燃烧特性参数,并且系统地分析了当量比、掺氢比和初始压力对燃烧的影响.结果表明:随着掺氢比的增大,火焰传播速率、层流燃烧速率、燃烧压力升高率和质量燃烧速率都明显增大,火焰发展期和燃烧持续期则随之缩短;当掺氢比较低时,随着当量比的升高,马克斯坦长度不断递减,即稀混合气的燃烧稳定性更高;当掺氢比较高时,随着当量比的升高,马克斯坦长度不断递增,即浓混合气的燃烧稳定性更高;最高燃烧压力随着初始压力的升高而升高,受掺氢比的影响相对较小.

The laminar combustion characteristics of dimethyl ether-hydrogen-air mixture were studied at various equivalence ratios, hydrogen fractions and initial pressures by using a constant volume combustion bomb. The influences of the equivalence ratio, the hydrogen fraction and the initial pressure on flame speed and combustion characteristics were analyzed. The results show that the flame speed, the laminar burning velocity and the mass burning rate increase with the increase of the hydrogen fraction. Increasing the hydrogen fraction will increase the peak combus- tion pressure and shorten the combustion duration. For small hydrogen fractions, the Markstein length decreases with the increase of the equivalence ratio, indicating that the lean mixture has higher flame front stability than the rich mixture. For large hydrogen fractions, the Markstein length increases with the increase of the equivalence ratio, indicating that the rich mixture has higher flame front stability than the lean mixture. the increase of initial pressure, and initial pressure Maximum combustion pressure increases with displays greater influence on combustion pressure than doping hydrogen.