铝粉尘云燃烧火焰形态分析实验研究

Experimental Study on Combustion Flame Shape Analysis of Aluminum Dust

为探索铝粉尘云燃烧火焰形态和灾变演化,基于改造的竖直开口实验管道,借助高速摄像仪和离子探针,研究火焰结构及变化,分析粒径因素对铝粉火焰前锋形态的影响。实验结果表明:铝粉燃烧能量的释放和空间束缚使燃烧转为爆燃,火焰前锋下方存在大片的燃烧反应区;铝粉粒径越小,颗粒氧化层破裂需要的热应力越小,越容易被点燃;随着铝粉粒径减小,热膨胀对火焰传播速度的影响明显增强。

In order to explore the flame morphology and catastrophic evolution of aluminum dust cloud combustion,based on the modified vertical open experimental pipeline,the flame structure and changes were studied with the aid of high-speed camera and ion probe,and the influence of particle size factors on the flame front shape of aluminum powder was analyzed.The experimental results showed that the release of combustion energy and space restraint of aluminum powder made the combustion turn to deflagration and there was a large combustion reaction zone below the flame front.The smaller the particle size of aluminum powder,the smaller the thermal stress required for the cracking of the oxide layer,and the easier it was to ignite.With the decrease of aluminum particle size,the influence of thermal expansion on flame propagation velocity was obviously enhanced.