形状系数对20 L球内铝粉分散特性的影响研究

doi:10.16265/j.cnki.issn1003-3033.2024.08.0712

摘要/Abstract

摘要：

为研究不同形状系数(SF)的铝粉在 20 L球型容器中的分散特征,通过建立描述气流携带粉尘形成两相分散系的非稳态数值模型,包括气体流动和粉尘颗粒运动轨迹方程,开展非稳态数值模拟,分析粉尘SF分别为0.2、0.4、0.6、0.8和1.0条件下的粉尘空间分布以及球室中心的湍流动能、速度随时间变化。结果表明:球室内气流携带粉尘分散可以分为进粉、扩散、稳定和沉降4个阶段,其分散均匀性和最大速度值随SF的增加而增强;SF越大,即颗粒形状越接近球形,铝粉尘的分散性越好;SF越小,粉尘容易堆积在壁面附近;标称浓度一定时,SF≤0.4,浓度峰值随SF的增加而增加;SF>0.4,浓度峰值随SF的增加而减小;铝粉-空气混合物的湍流动能最大值随SF值的增加而降低;铝粉颗粒的速度峰值随SF值的增加而升高。

关键词: 形状系数(SF), 20 L球, 铝粉尘, 粉尘质量浓度, 分散特性, 数值模拟

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

中图分类号:

X932爆炸安全与防火、防爆

关文玲, 金美华, 董呈杰. 形状系数对20 L球内铝粉分散特性的影响研究[J]. 中国安全科学学报, 2024, 34(8): 120-127.

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