基于激波管装置的乙烯氧化实验研究与动力学机理分析

Ethylene Oxidation Experimental Study and Kinetic Mechanism Analysis Based on Shock Tube

在乙烯/氧气化学计量比为1,温度1092-1743 K,压力1.3-3.0 atm(1 atm=101325 Pa)范围内,利用激波管测量了在摩尔分数为96%和75%两种不同氩气稀释度工况下的乙烯/氧气/氩气反应体系的着火延迟时间。实验结果表明,乙烯着火延迟时间在低稀释度下比高稀释度下短,着火延迟时间的对数与温度的倒数成良好线性关系,随着温度增加着火延迟时间缩短。此外,低稀释度下,能观察到爆轰(或者爆燃转爆轰)现象,而在高稀释度下,未发生爆轰现象。将四种不同机理模拟结果与实验结果比较,发现LLNL机理与实验结果吻合得较好。反应路径分析研究表明,稀释度对乙烯氧化反应路径无影响,而温度影响较大,温度增加,乙烯消耗路径由四条减少为三条,反应C_2H_4+H(+M)=C_2H_5(+M)由正向消耗乙烯变为逆向生成乙烯。

This study measures the ignition delay times of C_2H_4/O_2/Ar stoichiometric mixtures under Ar diluent mole fractions of 75% and 96% using the shock tube.The experimental temperatures range from 1092 to 1743 K and the pressures range from 1.3 to 3.0 atm（1 atm = 101325 Pa）.The logarithm of the ignition delay time is found to be a linear function of the reciprocal temperature.The ignition delay time is shorter in the lower diluent concentrations,as well as decreasing with increasing temperature.Moreover,detonation（or deflagration to detonation） is observed in the lower but not the higher diluent concentrations.In comparative simulations of four different mechanisms,the LLNL mechanism best fits the experimental results.Reaction path analysis shows that the ethylene oxidation paths are affected by temperature rather than diluent rate.With increasing temperature,the number of ethylene oxidation paths decrease from four to three because of the predominance of the reverse reaction C_2H_4＋ H（＋ M） → C_2H_5（＋ M）.