点火能量对粉尘爆炸行为的影响

Influence of ignition energy on dust explosion behavior

为防控工业粉尘爆炸和完善粉尘爆炸测试方法,在Siwek 20 L球形爆炸测试系统内,实验研究了不同点火能量下高、低挥发性粉尘的爆炸行为。对粉尘爆炸猛度(最大爆炸压力、最大升压速率和燃烧持续时间)、敏感度(爆炸下限)及惰性介质的抑爆效力随点火能量的变化规律进行了重点探讨。结果表明,增加点火能量能提高粉尘云爆炸能量和燃烧速率,低挥发性粉尘爆炸行为受点火能量的影响更显著。低挥发性粉尘在低质量浓度下无法被低点火能量充分引燃,爆炸不良效应显著;随着粉尘质量浓度的增加,爆炸不良效应不断减弱直至消失。低挥发性粉尘爆炸下限随点火能量增加急剧下降,而高挥发性粉尘爆炸下限受点火能量影响较小。惰性介质抑爆效力随点火能量增加而下降。建议采用5～10 kJ点火能量考察低挥发性粉尘爆炸下限及惰性介质对粉尘爆炸的抑制效力。研究结果有助于理解粉尘爆炸规律、完善测试方法和安全设计。

In order to prevent and control industrial dust explosion and improve the accuracy of dust explosion tests,an experimental research was carried out to have an insight into the explosion behavior of high-and low-volatile dusts induced by different ignition energies by using a Siwek 20 L spherical explosion test system.Ignition energy effect on dust explosion brisance（max.explosion pressure,max.pressure rising rate and combustion duration） and sensitivity（lower explosion limit） and the variation of explosion suppression effectiveness of inert substance along with the ignition energy were explored.Results show that higher ignition energy improves the explosion energy release and combustion rate of dust cloud;the effect of ignition energy on explosion behavior is more significant for less volatile dust.Incomplete deflagration of low-volatile dust under the condition of low ignition energy results in the adverse effect of explosion.The adverse effect of explosion becomes inconspicuous as the dust concentration increases.The lower explosion limit decreases sharply with the rise of ignition energy for low-volatile dust,while the lower explosion limit of high-volatile dust is not so sensitive to ignition energy.Moreover,explosion suppression effectiveness of inert substance decreases with the rise of ignition energy.The ignition energy of 5~10 kJ is the most appropriate for understanding the lower explosion limit of low-volatile dust and the explosion suppression effectiveness of inert substance.The above results may be valuable for understanding the dust explosion characteristics and completing the current dust explosion characteristics test and safety design.