初始压力和富氧系数对CH_(4)/O_(2)/N_(2)预混气体爆炸特性的影响

Effect of Initial Pressure and Oxygen Enrichment Factor on the Explosion Characteristics of CH_(4)/O_(2)/N_(2)Premixed Gases

为了探究甲烷CH_(4)在富氧和非常压条件下的爆炸危险性,确保CH_(4)气体在不同工况下的安全使用,借助5 L圆柱形爆炸装置,研究了初始压力p_(0)和富氧系数E对CH_(4)/O_(2)/N_(2)爆炸特性的影响。包括最大爆炸压力p_(max)、最大压力上升速率(d p/d t)max和最大压力到达时间t_(c)等衡量CH_(4)爆炸安全性的指标。结果表明:当E为0.21、0.25和0.30时,p_(max)随p_(0)的增加始终线性上升;而当E为0.35和0.40时,p_(max)随p_(0)的增加先缓慢线性上升、后快速线性上升;(d p/d t)max随p_(0)的增加分为线性上升和一阶指数快速上升。在E为0.21和0.25时,t_(c)随p_(0)的增加而线性增大,因为在燃烧初始阶段CH_(4)活化自由基的销毁速率增加,降低了反应速率和燃速,引起预混气体t_(c)的延长;但随着E的增加,氧气的促进作用与自由基销毁的抑制作用形成新的竞争效应,使得t_(c)先增加、后下降。

In order to investigate the explosion hazards of methane CH_(4)under oxygen-rich and non-pressure conditions,and ensure the safe use of CH_(4)gas under different operating conditions,the effects of initial pressure p_(0)and oxygen enrichment factor E on the explosion characteristics of CH_(4)/O_(2)/N_(2)were studied using a 5 L cylindrical explosive device.Indicators such as maximum explosion pressure p_(max),maximum pressure rise rate(d p/d t)max,and maximum pressure arrival time t_(c) were used to measure the explosion safety of CH_(4).The results show that when E is 0.21,0.25,and 0.30,p_(max)always increases linearly with the increase of p_(0);When E is 0.35 and 0.40,p_(max)first slowly increases linearly with the increase of p_(0),and then rapidly increases linearly;(d p/d t)max can be divided into linear increase and first-order exponential rapid increase with the increase of p_(0).When E is 0.21 and 0.25,t_(c) linearly increases with the increase of p_(0),as the destruction rate of CH_(4)activated radicals increases during the initial combustion stage,reducing the reaction rate and bur-ning rate,leading to an extension of t_(c) of premixed gas.But as E increases,the promoting effect of oxygen and the inhibiting effect of free radical destruction form a new competitive effect,causing t_(c) to increase first and then decrease.