中大尺度管道铝粉尘云爆炸压力及火焰传播规律

Explosion Pressure and Flame Propagation Regularity of Aluminum Dust Cloud in Large and Medium-Scale Pipelines

  • 摘要: 近年来,工贸行业铝粉尘爆炸事故频发,严重威胁人员与设备设施的安全. 为研究铝粉尘云在实际工业管道中的爆炸压力、火焰传播特性及影响因素,搭建了中大尺度透明管道金属粉尘爆炸测试系统. 通过爆炸超压监测获得管道沿程测点爆炸压力−时间曲线,采用高速摄影捕获粉尘云爆炸火焰传播动态行为特征,结合图像处理得到不同质量浓度、粒径下火焰前锋传播速度. 结果表明:随着铝粉尘云质量浓度增大,各测点的爆炸压力显著增强;随着粒径的增大,最大爆炸压力显著降低,爆炸峰值压力到达所需时间变长,且在达到峰值之前压力的波动更加明显. 铝粉尘云爆炸火焰传播在不同管段先后经历缓慢加速、快速增长和速率突跃变化三个阶段,火焰前锋传播速度呈现出脉动−加速−再脉动的上升趋势. 该现象可归因于铝粉颗粒在吸热和放热过程中的动态平衡,以及它们与燃烧反应之间的相互作用. 此外,局部湍流和粉尘云质量浓度的非均匀分布状态也是导致火焰传播速度脉动增加的重要因素. 研究结果能够为工业生产中粉尘防爆、抑爆提供科学依据与理论支撑.

     

    Abstract: In recent years, the frequency of aluminum dust explosion accidents in the industrial and trade sectors has increased, posing a serious threat to the safety of personnel and equipment. To investigate explosion pressure, flame propagation characteristics, and influencing factors of aluminum dust clouds in actual industrial pipelines, a medium-to-large-scale transparent pipeline metal dust explosion testing system was established. By monitoring explosion overpressure, time-pressure curves of the explosion at various points along the pipeline were obtained, and high-speed photography was employed to capture dynamic behavior characteristics of flame propagation in dust cloud explosion. Image processing techniques were employed to determine flame front propagation velocity under different concentrations and particle sizes. The results indicate that as concentration of aluminum dust cloud increased, explosion pressure at each measurement point significantly rose. Conversely, with increasing particle size, maximum explosion pressure markedly decreased, time to reach peak explosion pressure was prolonged, and pressure fluctuations became more pronounced before reaching the peak. Flame propagation in aluminum dust cloud explosions experienced three successive phases in different pipe segments: slow acceleration, rapid growth, and abrupt velocity changes, with flame front propagation velocity exhibiting a trend of pulsation, acceleration, and then pulsation again. This phenomenon can be attributed to the dynamic equilibrium of aluminum dust particles during endothermic and exothermic processes, as well as their interactions with combustion reactions. Additionally, localized turbulence and non-uniform distribution of dust cloud concentration were significant factors contributing to increased pulsation in flame propagation velocity. The findings of this study can provide a scientific basis and theoretical support for dust explosion prevention and mitigation in industrial production.

     

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