Study on effect of shape factor on dispersion characteristics of aluminum powder inside 20 L sphere

doi:10.16265/j.cnki.issn1003-3033.2024.08.0712

Abstract

Abstract:

The aim of this study is to investigate the dispersion of aluminium powders with different SF in a 20 L spherical container. By establishing a numerical model describing the formation of a two-phase dispersion system of dust carried by a gas stream, including the equations of the gas flow and the trajectory of the dust particles, unsteady numerical simulations were carried out. The spatial distribution of dust, the turbulent kinetic energy and velocity at the center of the spherical chamber with time changes were analyzed under the conditions of SF of 0.2, 0.4, 0.6, 0.8 and 1.0, respectively. The results show that the dispersion of airflow-carried dust inside the ball chamber can be divided into four stages, including powder intake, diffusion, stabilization and settling, and the dispersion uniformity and maximum velocity values are enhanced with the increase of SF. The bigger SF is, the closer the particle shape is to spherical, and the better the dispersion of aluminum dust is. The smaller SF is, the easier the dust will accumulate near the wall surface. When the nominal concentration is certain, SF ≤ 0.4, the peak concentration increases with the increase of SF, SF > 0.4, the peak concentration decreases with the increase of SF. The maximum value of the turbulent kinetic energy of the aluminum powder-air mixture decreases with increasing values of SF, the peak velocity of the aluminum powder particles increases with increasing values of SF.

Key words: shape factor, 20 L sphere, aluminum dust, dust mass concentration, dispersion characteristics, numerical simulation

CLC Number:

X932爆炸安全与防火、防爆

GUAN Wenling, JIN Meihua, DONG Chengjie. Study on effect of shape factor on dispersion characteristics of aluminum powder inside 20 L sphere[J]. China Safety Science Journal, 2024, 34(8): 120-127.

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参数	数值
SF	0.2,0.4,0.6,0. 8,1.0
粒径/μm	75
质量浓度/(kg·m^-3)	0.25