二甲醚/氨对冲扩散火焰熄灭特性及动力学分析

Extinction Limits and Chemical Kinetics Analysis of Counterflow Diffusion Flames of Dimethyl Ether/Ammonia

氨作为一种应用前景广泛的清洁燃料,近些年来受到广泛关注。本文利用对冲火焰试验装置研究了二甲醚/氨混合物冷焰和热焰的熄灭特性;并对二甲醚/氨的低温和高温化学动力学进行了分析。结果表明,随掺氨比的增加,二甲醚/氨混合物冷焰和热焰熄灭极限减小。在二甲醚/氨混合物冷焰中,主要通过氨与二甲醚抢夺OH、反应DME+NO⇐⇒R+HNO以及反应RO_(2)+NO⇐⇒RO+NO_(2)三种途径抑制二甲醚的低温反应性。在二甲醚/氨混合物热焰中,主要通过氨产生的OH、H和O自由基反应及反应HCCO+NO⇐⇒HCNO+CO和HCCO+NO⇐⇒HCN+CO_(2)来提高二甲醚的高温反应性。此外,研究发现在二甲醚/氨混合物冷焰和热焰中主要的氮氧化物分别为NO_(2)和NO。

Ammonia has recently received much attention as a novel clean energy with broad application prospects.The paper focuses on the extinction limits of dimethyl ether/ammonia mixtures cool and hot diffusion flames by an atmospheric counterflow burner.The low and high temperature chemical kinetics of dimethyl ether/ammonia are analyzed.The results show that the extinction limits of dimethyl ether/ammonia mixtures cool and hot diffusion flames decrease with the increase of the ammonia blend ratios.For dimethyl ether/ammonia cool flames,the low temperature reactivity of dimethyl ether is inhibited mainly through three aspects:ammonia and dimethyl ether vie OH,DME+NO⇐⇒R+HNO and RO_(2)+NO⇐⇒RO+NO_(2).For dimethyl ether/ammonia diffusion hot flame,the high temperature reactivity of dimethyl ether is improved by the reaction of OH,H and O radicals generated by ammonia with dimethyl ether and the reaction of HCCO+NO⇐⇒HCNO+CO and HCCO+NO⇐⇒HCN+CO_(2).Moreover,this research shows that the main oxynitrides in dimethyl ether/ammonia cold flame and hot flame are NO_(2)and NO respectively.