氨气与甲烷混合气自燃过程的化学动力学研究  

Chemical Kinetics Study of the Autoignition of NH3/CH4 Mixtures

作　　者：徐昊 何志霞 戴礼明[1] 王谦[1] Xu Hao;He Zhixia;Dai Liming;Wang Qian(School of Energy and Power Engineering,Jiangsu University,Zhenjiang 212013,China;Institute for Energy Research,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学能源与动力工程学院,江苏镇江212013 [2]江苏大学能源研究院,江苏镇江212013

出　　处：《内燃机学报》2023年第1期1-8,共8页Transactions of Csice

基　　金：国家自然科学基金资助项目(51876083)。

摘　　要：在当量比φ=0.5、压力为2~7 MPa以及温度从930 K到1 140 K的条件下,用快速压缩机研究氨气(NH_(3))和甲烷(CH4)混合气的着火延迟时间,其中CH_(4)占总燃料的摩尔分数分别为0、5%、10%及50%.另外,在φ为1.0和2.0的条件下对掺入10%CH_(4)的混合气进行着火延迟时间测试.CH_(4)对NH_(3)的着火过程具有非常明显的促进作用,随着CH_(4)占总燃料的比例越来越高,混合气的着火延迟时间缩短,同时CH4对着火的促进作用趋于平缓.含10%CH_(4)的NH_(3)的着火延迟时间在φ为0.5和1.0的条件下变化很小,而当φ=2.0时着火延迟时间增加约50%.利用试验数据对6种不同的NH_(3)氧化机理进行了验证,所开发的机理预测着火延迟时间最为准确,除了在最高温度,CH_(4)摩尔分数为50%时试验与计算差异达到了50%,其他所有条件下机理的预测结果与试验结果差距都小于30%.利用开发的机理进行敏感性分析,结果表明:当CH_(4)摩尔分数为5%和10%时,反应CH_(4)+NH_(2)=CH_(3)+NH_(3)对稀薄燃烧条件下混合气的着火延迟时间有显著的促进作用;但当CH4摩尔分数为50%时,该反应会表现出轻微的抑制作用.Ignition delay times of NH_(3)/CH_(4)mixtures with CH_(4)mole fractions of 0,5%,10% and 50% were measured in a rapid compression machine at equivalence ratio of 0.5,pressures from 2-7 MPa and temperatures from 930 K to 1 140 K. In addition,measurements were performed for NH_(3)mixtures with 10% CH_(4)at φ=1.0 and 2.0.Methane shows a strong ignition-enhancing effect on NH_(3),which levels off at higher CH_(4)fractions,as the ignition delay time approaches that of pure methane. Autoignition delay times at 10% CH_(4)at φ=0.5 and 1.0 are indistinguishable,while an increase of ignition delay times by factor of 1.5 was observed upon increasing φ to 2.0. The experimental data were used to evaluate six NH_(3)oxidation mechanisms capable of simulating NH_(3)/CH_(4)mixtures. The mechanism previously used shows the best performance:generally,it predicts the measured ignition delay times to better than 30% for all conditions,except for 50% CH_(4)addition for which the differences increase up to 50% at the highest temperature. Sensitivity analysis based on the mechanism used indicates that under lean conditions the reaction CH_(4)+NH_(2)=CH_(3)+NH_(3)significantly promotes ignition for CH_(4)addition(5% and 10%),but becomes modestly ignition-inhibiting at 50% CH_(4).

关 键 词：氨气与甲烷混合气 化学动力学 着火延迟时间 快速压缩机 

分 类 号：TK438.9[动力工程及工程热物理—动力机械及工程]