以2 μm铝粉为介质,在内径68 mm、高305 mm的钢制圆柱容器顶端连接内径25 mm、不同长度的钢制泄爆管,开展了粉尘爆炸泄放实验.通过分别改变泄爆管长度及粉尘的质量浓度,研究粉尘爆炸泄放过程中容器及泄爆管内的压力特性,重点在探索泄放过程中二次爆炸发生的条件.结果表明,在本实验条件下,当泄爆管长度LT≥1 500 mm,粉尘质量浓度p≥500 g/m3时,泄爆管内发生二次爆炸的几率很高.二次爆炸产生的压力波分别向爆炸容器及泄爆管末端2个方向传播.向爆炸容器传播的压力波阻碍并扰乱泄放过程,导致容器内残余未燃粉尘反应,使容器内压力出现二次峰值.%The aluminum powder of 2 μm particle size was taken as the medium and a rrnseries of dust explosion relief experiments were carried out by linking rrnthe steel relief pipes with 25 mm internal diameter to the top of the rrncylindrical steel vessel with 68 mm internal diameter and 305 mm height. rrnThe steel relief pipe length and the dust mass concentration were rrnadjusted, respectively, to investigate the pressure characteristics in the rrnvessel and the relief pipe and to explore principally the secondary rrnexplosion-induced condition in the explosion relief process. Experimental rrnresults demonstrate that secondary explosion may occur when the relief rrnpipe length and dust mass concentration are no less than 1 500 mm and 500 rrng/m3, respectively. The pressure waves induced by secondary explosion rrnpropagate toward both the vessel and the relief pipe end. The pressure rrnwaves propagating toward the vessel disturb the relief process and induce rrnthe residual unburnt combustible mixture in the vessel react. Hence, rrnsecondary pressure peak appears in the vessel.
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