基于CHEMKIN的可燃气体爆炸下限模拟研究

Simulation research of lower explosion limit for flammable gas based on CHEMKIN

基于CHEMKIN软件的绝热燃烧相平衡模型,模拟甲烷、乙烷、丙烷在绝热状态下的燃烧实验,分别获得相应条件下的绝热温升和绝热压升。随着可燃气体体积分数的增加,绝热温升和绝热压升均呈现先上升后下降的趋势。将绝热压升为0.32MPa时对应的可燃气体浓度作为该体系的爆炸下限值,通过计算获得三种气体的爆炸下限值,并与文献值进行对比,吻合程度较好。利用该模型对含氮混合气体的燃烧过程进行模拟,分析惰性介质氮气对爆炸反应的抑制机理,并利用压力判断准则计算混合气体的爆炸下限值。预测值与文献值的最大绝对误差为0.54%,平均绝对误差为0.274%。结果表明所建立的绝热燃烧相平衡模型能够准确地预测单一体系和含氮混合体系等可燃气体的爆炸下限。

The phase equilibrium model in the CHEMKIN software was used to simulate the combustion experiment in adiabatic condition for methane, ethane, propane, and the adiabatic temperature rise and adiabatic pressure rise of the elemental system were obtained under certain initial conditions respectively. The adiabatic temperature rise and the adiabatic pressure rise rose and then declined with the rise of the concentration of combustible gas. The lower explosion limit （LEL） was predicted by the concentration of combustible gas when the adiabatic pressure rise up to 0. 32 MPa, and the predicted value were compared with the literature value, the good prediction results had been achieved. The model was used to simulate the combustion process of mixed gas containing Nitrogen, the explosion reaction inhibition mechanism for the inert medium Nitrogen was analyzed. The LEL of the mixed gas was calculated by pressure judgement criterion. It is concluded that the maximum absolute error was 0. 54%, the average absolute error was 0. 274%. Results showed that the LEL of combustible gas and gas mixture containing nitrogen were predicted accurately based on the adiabatic combustion phase equilibrium model.