磁场对乙烯预混气体爆炸自由基影响机理

Mechanism of Magnetic Field on the Explosive Radical of Ethylene Premixed Gas

为探究磁场对预混气体爆炸特征的影响及机理,以乙烯为例,通过自行研制的实验系统研究磁场对预混乙烯/空气爆炸压力、火焰传播速度等爆炸特征的影响,利用Chemkin‑Pro模拟了乙烯爆炸链式反应过程,研究了乙烯爆炸链式反应的关键自由基,理论计算了磁场对自由基粒子的作用力,探讨了磁场影响预混气体爆炸的自由基机理。结果表明,在最大磁场强度3300 Gs作用下,6.5%乙烯最大爆炸压力降低18.18%、爆炸压力上升速率降低17.33%,沿着火焰传播方向,磁场对乙烯爆炸火焰传播速度呈现先促进后抑制的效应,抑制效果大于促进效果,总体呈现抑制效应。乙烯爆炸过程中的关键自由基为·H、·O、·CH_(2)。自由基在磁场作用下的受力与自由基的磁化强度成正比,乙烯爆炸关键自由基的磁化强度各不相同,在磁场作用下,自由基出现分层现象,减少了不同自由基之间的碰撞,降低基元反应速率,从而抑制乙烯爆炸。

To explore the effect of magnetic field on the explosion characteristics of premixed gas and its mechanism,taking eth‑ylene as an example,the influence law of magnetic field on the explosion characteristics of premixed ethylene/air was experi‑mentally studied.The chain reaction process of ethylene explosion was numerically simulated.The influence of magnetic field force on key free radicals was theoretically analyzed.The transient pressure of ethylene explosion was measured by pressure sen‑sors and the flame propagation velocities were measured by explosion velocity apparatus.Results show that under the maximum magnetic field intensity of 3300 Gs,the maximum explosion pressure of 6.5%ethylene decreased by 18.18%and the explosion pressure rise rate reduced by 17.33%.Along the flame propagation direction,the magnetic field firstly promoted and then sup‑pressed the flame propagation speed of ethylene explosion,in which the suppression effect was greater than the promotion ef‑fect.The ethylene explosion was simulated by Chemkin‑pro software,and the key free radicals in ethylene explosion were ob‑tained.Different types of free radicals have different intensities of magnetization.Force of free radical under magnetic field is pro‑portional to magnetization of free radical.The magnetic field force has a greater impact on free radicals with high magnetization,and no impact on anti‑magnetic substances.Different types of free radicals appear stratification phenomenon under magnetic field.The collisions between different types of free radicals were reduced,and the elementary reaction rate was decreased,which suppressed the ethylene explosion.