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为探索受限空间内惰性粉体对铝粉火焰结构及火焰传播特性的影响机制,利用小尺寸开口竖直管道和高速摄影仪和微细热电偶,研究添加质量分数为20%的NH_4H_2PO_4和SiO_2粉体时铝粉燃烧火焰形态、火焰温度和火焰传播速度等参数的分布特征。结果表明:NH_4H_2PO_4和SiO_2粉体能稀释铝粉尘云浓度,有效减弱反应强度;铝粉粒径增大,惰性粉体对铝粉最高火焰温度的抑制作用先增大后减小,当铝粉粒径为30μm时,抑制效果最显著;惰性粉体对铝粉火焰传播速度的抑制作用与铝粉粒径负相关;NH_4H_2PO_4对铝粉火焰的抑制效果比SiO_2明显。
In order to explore the influence mechanism of inert powders on the flame structure and flame propagation characteristics of aluminum powder in confined space, the effect of adding NH_4H_2PO_4 and SiO_2 powders with mass fraction of 20% was studied by using small-size vertical pipes and high-speed cameras and micro thermocouples. Body shape flame burning flame, flame temperature and flame propagation velocity and other parameters of the distribution characteristics. The results show that: NH_4H_2PO_4 and SiO_2 powders can dilute the dust concentration of aluminum dust effectively reduce the reaction strength; the particle size of aluminum powder increases, the inhibitory effect of inert powder on the maximum flame temperature of aluminum powder first increases and then decreases; The inhibition effect was the most significant when the diameter was 30μm. The inhibition of the flame propagation velocity by aluminum powder was negatively correlated with the particle size of aluminum powder. The inhibition effect of NH4H2PO4 on aluminum flames was more obvious than that of SiO2 powder.