碳酸二甲酯着火化学反应动力学模型研究

Modeling on Ignition Delay Time of Dimethyl Carbonate

利用激波管测量了碳酸二甲酯(DMC)在不同压力、温度、当量比和燃料浓度下的着火延迟期,并给出了着火延迟期的Arrhenius拟合关联式.对现有的DMC化学反应模型Glaude模型预测混合气着火过程进行了验证,Glaude模型预测的着火延迟期明显高于试验测量值.基于试验数据和理论分析,提出了一个DMC化学反应模型Present模型.Present模型能够很好地预测DMC的着火延迟期,并且在预测扩散火焰物种浓度方面也取得了很好的效果.通过对着火过程进行化学反应路径分析可知,DMC燃料分子的消耗主要靠脱氢反应,而燃料单分子分解反应消耗的燃料所占的比例较小.

Ignition delay time of dimethyl carbonate was measured in a shock tube at T=1,100—1,600,K,p=0.12—1.0,MPa,φ=0.5—2.0,and 0.5%—2.0% fuel concentration. The only DMC model of Glaude model has been validated by ignition delay time and it gives the higher prediction than the measured data. A chemical kinetic model(Present model)was developed and it can well predict the ignition delay time of dimethyl carbonate. Further validation of the modified DMC model was made on the basis of the opposed flow diffusion flame data in literatures.Reaction pathway analysis shows that DMC molecule is primarily consumed through the H-abstractions. Sensitivity analysis indicates several key fuel-species reactions affect the DMC ignition delay time.