初始压力和富氧系数对CH4/O2/N2预混气体爆炸特性的影响

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CH₄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p₀和富氧系数E对CH₄/O₂/N₂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（dp/dt）_max和最大压力到达时间t_c等衡量CH₄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p₀的增加始终线性上升；而当E为 0.35和0.40时，p_max随p₀的增加先缓慢线性上升、后快速线性上升；（dp/dt）_max随p₀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p₀的增加而线性增大，因为在燃烧初始阶段CH₄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。

Effect of Initial Pressure and Oxygen Enrichment Factor on the Explosion Characteristics of CH4/O2/N2 Premixed Gases

In order to investigate the explosion hazards of methane CH₄ under oxygen-rich and non-pressure conditions, and ensure the safe use of CH₄ gas under different operating conditions, the effects of initial pressure p₀?and oxygen enrichment factor E?on the explosion characteristics of CH₄/O₂/N₂ were studied using a 5 L cylindrical explosive device. Indicators such as maximum explosion pressure p_max, maximum pressure rise rate (dp/dt)_max, and maximum pressure arrival time t_c were used to measure the explosion safety of CH₄. The results show that when E?is 0.21, 0.25, and 0.30, p_max?always increases linearly with the increase of p₀; When E?is 0.35 and 0.40, p_max first slowly increases linearly with the increase of p₀, and then rapidly increases linearly; (dp/dt)_max?can be divided into linear increase and first-order exponential rapid increase with the increase of p₀. When E?is 0.21 and 0.25, t_c linearly increases with the increase of p₀, as the destruction rate of CH₄ activated radicals increases during the initial combustion stage, reducing the reaction rate and burning 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.