静电场驱动的镁铝合金粉尘爆炸特性研究

Study on the characteristics of magnesium-aluminum alloy dust explosion driven by an electrostatic field

为了揭示静电因素驱动下的镁铝合金粉尘的爆炸特性,基于直流高压发生器和20 L球形爆炸测试装置,搭建了静电环境粉尘爆炸特性测试系统,测定了静电电压为3 kV、6 kV、9 kV与粉尘质量浓度为250 g/m^(3)、500 g/m^(3)、750 g/m^(3)、1000 g/m^(3)耦合条件下镁铝合金粉的爆炸特性。结果表明:静电场的存在主要影响爆炸时间和最大压力上升速率(dp/dt)_(max),对最大爆炸压力无显著影响;在同一质量浓度下,峰值压力时刻t_(max)随电压上升而缩短,如250 g/m^(3)下,静电场电压9 kV时峰值压力时刻t_(max)是压力0时的52.5%;将粉尘云爆炸过程按喷粉时刻、粉尘着火时刻、最大压力上升速率(dp/dt)_(max)时刻、峰值压力时刻t_(max)四个时刻划分为3个阶段(即t_(2)、t_(3)、t_(4)),静电场的存在使t_(2)和t_(3)缩短,对t_(4)则影响较小,整体而言静电场会加速镁铝合金粉尘爆炸过程。该研究可为深入认识静电环境下镁铝合金粉尘的爆炸机理和镁铝合金粉尘爆炸事故防治提供参考。

To reveal the explosive characteristics of magnesium-aluminum alloy dust driven by electrostatic factors,a test system for electrostatic environmental dust explosion characteristics was built based on a DC high-voltage generator and a 20 L sphere explosive device.The dust was ignited by chemical ignition.The explosive characteristics of magnesium-aluminum alloy dust under the coupling conditions of the electrostatic voltage of 3 kV,6 kV,and 9 kV and the dust concentration of 250 g/m^(3),500 g/m^(3),750 g/m^(3),and 1000 g/m^(3)were measured.The results show that the existence of an electrostatic field mainly affects the explosion time and the maximum rise rate(dp/dt)_(max)of the pressure,but has no obvious effect on the maximum explosion pressure.The dust cloud explosion can be divided into three stages(ie,t_(2),t_(3),t_(4))according to four time nodes of powder ejection:dust ignition time,the maximum pressure rise rate(dp/dt)_(max)time,and the peak pressure time t_(max).The electrostatic field will shorten t_(2) and t_(3),but has little effect on t_(4) and maximum explosion pressure.At the same concentration,the peak pressure time t_(max)decreases as the voltage rises.For example,at a concentration of 250 g/m^(3),the peak pressure time t_(max)when the electrostatic field voltage is 9 kV is 52.5%of that at 0.On the whole,the electrostatic field accelerates the explosive process of magnesium-aluminum alloy dust.The vapor phase of the metal particles in the magnesium-aluminum alloy dust escapes under the influence of electrostatic field and the gas phase ignition occurs quickly.At the same time,the electrostatic field accelerates the flame propagation speed and the dust explosion speed.This research provides a reference for the thorough understanding of the explosion mechanism of magnesium-aluminum alloy dust in an electrostatic environment and the prevention of explosion accidents of magnesium-aluminum alloy dust.