首页|Deflagration characteristics of freely propagating flames in magnesium hydride dust clouds

Deflagration characteristics of freely propagating flames in magnesium hydride dust clouds

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The flame propagation processes of MgH2 dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH2 dust clouds were recon-structed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were analyzed.The experimental results showed that the average flame propagation velocities of 23 pm,40 pm,60 pm and 103 pm MgH2 dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,respectively.The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were smaller.The flame structures of MgH2 dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of particles.The falling velocities of 23 pm and 40 pm MgH2 particles were 2.24 cm/s and 6.71 cm/s,respectively.While the falling velocities of 60 pm and 103 pm MgH2 particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the flame.Furthermore,the dehydrogenation reaction had a significant effect on the com-bustion performance of MgH2 dust.The combustion of H2 enhanced the ignition and combustion characteristics of MgH2 dust,resulting in a much higher explosion power than the pure Mg dust.The micro-structure characteristics and combustion residues composition analysis of MgH2 dust indicated that the combustion control mechanism of MgH2 dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.

Magnesium hydride dustFlame combustion mechanismParticle sizeDust explosionTwo-color pyrometer

Qiwei Zhang、Yangfan Cheng、Beibei Zhang、Danyi Li、Zhaowu Shen

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School of Chemical Engineering,Anhui University of Science and Technology,Huainan 232001,Anhui,PR China

School of Engineering Science,University of Science and Technology of China,Hefei 230027,Anhui,PR China

School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan 232001,Anhui,PR China

Anhui Engineering Laboratory of Explosive Materials and Technology,Anhui University of Science and Technology,Huainan 232001,Anhui,PR China

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National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaOutstanding Youth Project of Natural Science Foundation of Anhui ProvinceMajor Project of Anhui University Natural Science Foundation

12272001119720462108085Y02KJ2020ZD30

2024

10.1016/j.dt.2023.03.003

防务技术
中国兵工学会

防务技术

CSTPCD
影响因子：0.358
ISSN：2214-9147
年,卷(期)：2024.(1)
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