油气爆炸在细长密闭管道内的振荡传播特性

Oscillation propagation characteristics of gasoline-air mixture explosion in elongated closed tubes

针对细长密闭管道内汽油蒸气-空气混合气爆炸的振荡传播特性进行实验。研究表明:细长密闭管道内的油气爆炸分为振荡和非振荡两种爆炸模式;振荡爆炸超压呈现出锯齿状振荡特征,其超压增长期由4个阶段组成:第1阶段无明显的压力上升;第2阶段的高压力上升速率与快速的火焰有关;第3阶段的超压振幅以抛物线形式增长,此阶段是否有压力振荡与油气浓度、管道长径比有关,第3阶段的振荡周期随时间减小,振荡周期与火焰锋面前方的未燃区长度有关;第4阶段的超压振幅以指数形式增长,振荡周期趋于稳定并随管道长度的增加呈线性关系增加,振荡周期受到油气浓度的影响;振荡爆炸只在一定油气浓度范围内发生,且振荡爆炸的发生与油气浓度、管道长径比有关;振荡爆炸极限范围及其在油气的爆炸极限内所占比例均随管道长径比的增加而增大。

Oscillation propagation characteristics of gasoline-air mixture explosion were tested in several elongated closed tubes. The results showed that gasoline-air mixture explosion has two modes including oscillation and nonoscillation; oscillation explosion overpressures exhibit a saw-toothed oscillation characteristic,their growth interval consists of four stages; the 1st stage has no significant increase in pressure; the high rate of pressure rise for the 2nd stage is associated with very fast flame speed; the overpressure amplitude of the 3rd stage grows in a parabolic curve form,if there is a pressure oscillation at this stage is related to gasoline-air mixture concentration and tube＇s length to diameter ratio,the oscillation period of this stage decreases with increase in time,the oscillation period is related to the length of unburned zone in front of flame front; the overpressure amplitude of the 4th stage increases exponentially,the oscillation period tends to be stable and increases linearly with increase in tube length,it is also affected by gasoline-air mixture concentration; oscillations explosions occur only within a certain range of gasoline-air mixture concentration, the occurrence of oscillation explosion is associated with gasoline-air mixture concentration and tube ＇s length to diameter ratio; the limit range of oscillation explosion and its proportion in the gasoline-air explosion limit increase with increase in tube＇s length to diameter ratio.