激波诱导瓦斯爆炸的动力学特性及影响因素

Kinetic characteristics and influencing factors of gas explosion induced by shock wave

通过修改化学动力学计算软件CHEMKINⅢ中的SHOCK程序包,建立了激波管中激波诱导瓦斯爆炸过程的计算模型,化学反应采用了详细反应机理(包括53种组分、325个反应)。对激波诱导瓦斯爆炸过程中混合气温度、冲击波传播速度、反应物(甲烷、氧气)摩尔分数、活化中心(O、H)摩尔分数、部分致灾性气体(CO、CO2、NO、NO2)摩尔分数的变化趋势进行了详细分析。同时,分析了瓦斯爆炸前混合气初始压力及初始混合气组成对激波诱导瓦斯爆炸动力学特性的影响。结果表明:瓦斯爆炸后CO的摩尔分数达到0.07左右,CO2的摩尔分数为0.02左右,NO的摩尔分数为0.001左右,NO2的摩尔分数则在10-6左右;随着瓦斯爆炸前混合气初始压力的提高以及混合气中甲烷体积分数的降低,瓦斯引爆时间将缩短,爆炸后温度将降低,但压力将升高,同时,爆炸后CO的摩尔分数将降低,NO的摩尔分数将提高。

By amending the SHOCK code in the Fortran chemical kinetics package, CHEMKIN Ⅲ, a computational model was built for the shock wave-induced gas explosion in a shock tube. And, the detailed reaction mechanisms involving 53 species and 325 reactions were adopted in the model above. The built computational model was used to analyze the evolvements of the following parameters： mixed gas temperature, shock wave velocity, the mole fractions of reactants （CH4 and O2）, the mole fractions of active centers （O, H）, and the mole fractions of catastrophic gases （CO, CO2, NO and NO2） in the process of gas explosion induced by shock wave. Furthermore, the effects of the initial pressure and the mixed gas composition before gas explosion on the kinetic characteristics of gas explosion induced by shock wave were discussed. The results show that the mole fractions of CO, CO2, NO and NO2 are about 0. 07, 0. 02, 0. 001 and 10^-6 , respectively, after gas explosion. With the increase of the initial pressure and the decrease of the CH4 fraction in the mixed gas, the detonation time of gas explosion shortens, the temperature decreases, but the pressure increases after gas explosion. Meanwhile, the mole fraction of CO decreases, the mole fraction of NO increases.