Abstract:

To study the effects of particle size on the deflagration behaviors and temperature distribution characteristics of TiH₂ dust cloud, a 20 L spherical dust explosion test system and a 1.2 L Hartmann tube test system were employed to conduct a comparative analysis for the deflagration characteristics of TiH₂ dust clouds with different particle sizes of 5.3, 17.1 and 27.8 μm. Additionally, flame temperature distribution characteristics were obtained by the two-color pyrometer technique. The experimental results showed that with the increase of dust concentration, the P_max and (dP/dt)_max values of the TiH₂ with three particle sizes all increased first and then decreased. As the particle size of TiH₂ dust increased, the values of P_max, (dP/dt)_max and K_St all decreased, and consequently lowered the explosion risk. Furthermore, as the dust particle size enlarged, the flame was more dispersed, the luminous intensity decreased and the propagation speed was slower. The overall flame temperature distribution of small-particle TiH₂ dust cloud is more uniform, and local high-temperature areas appear at the edge of the flame of large-particle TiH₂ dust cloud. The larger the particle size, the more obvious the local high-temperature area, and the more irregular the flame shape. The research results could provide theoretical reference for the safe production and explosion prevention of TiH₂ powder materials.

Key words: TiH₂ dust, particle size, two-color pyrometer, deflagration characteristics, temperature distribution

摘要：

为了探究粒径对TiH₂粉尘云燃爆特性及温度分布特征的影响，采用20 L球形爆炸测试系统和1.2 L哈特曼管测试系统对5.3、17.1、27.8 μm TiH₂粉尘云的燃爆特性进行对比分析，并基于比色测温技术重构出粉尘火焰温度分布云图。实验结果表明：随着粉尘浓度的增大，3种粒径TiH₂的P_max及(dP/dt)_max均呈先增大后减小的趋势；随着TiH₂粉尘粒径的增大，P_max、(dP/dt)_max和K_St均减小，爆炸危险性降低；此外，随着粉尘粒径的增大，TiH₂粉尘云火焰变离散，发光强度变低，火焰传播速度减慢；小粒径TiH₂粉尘云整体火焰温度分布更均匀，大粒径TiH₂粉尘云火焰边缘出现局部高温区，粒径越大局部高温区越明显且火焰形状越不规则。研究结果可为TiH₂粉末材料的安全生产和爆炸防控提供理论参考。

关键词: TiH₂粉尘, 粒径, 比色测温, 燃爆特性, 温度分布