抛光工艺中镁铝合金粉燃爆参数分析

Analysis of magnesium-aluminum alloy powder burning explosion parameters in the polishing process

采用粉尘云最低着火温度测试装置及20 L球形爆炸实验系统设计研究微米级镁铝合金粉爆炸特性参数。研究结果表明:镁铝合金粉尘云最低着火温度随分散压力的增大呈现先减少后增加的趋势,分散压力工况点对应最低的着火温度随着粒径的减少而出现下移现象;镁铝合金粉存在1个临界质量浓度,当镁铝合金粉尘质量浓度低于临界质量浓度时,其最低着火温度受粉尘质量浓度的影响较大,当粉尘质量浓度大于临界质量浓度时,其最低着火温度受粉尘质量浓度影响较小,镁铝合金粉临界质量浓度为4540 g/m^3;在同一粒径下爆炸压力随着质量浓度的增加先增大后减小,并存在1个最大爆炸质量浓度使得爆炸压力达到最大值,在1750 g/m^3粉尘质量浓度下,粒径为502.2,293.6和59.8μm的镁铝合金粉均达到最大的爆炸压力,并在500 g/m^3粉尘质量浓度下,粒径为502.2,293.6和59.8μm镁铝合金粉的极限氧体积分数分别为15%,13%和4%。

The explosion characteristic parameters of micron magnesium-aluminum alloy powder were studied by using 20 L spherical explosion experimental system and testing device of minimum ignition temperature of dust cloud.The results show that the minimum ignition temperature of magnesium-aluminum alloy dust cloud firstly decreases and then increases with the increase of dispersion pressure.The minimum ignition temperature corresponding to dispersion pressure working point decreases with the decrease of particle size.There is a critical mass concentration when the dust mass concentration of magnesium-aluminum alloy is lower than the critical mass concentration,and the minimum ignition temperature is greatly affected by the dust mass concentration.When the dust mass concentration is higher than the critical mass concentration,the minimum ignition temperature is less affected by the dust mass concentration,and the critical mass concentration of magnesium-aluminum alloy powder is 4540 g/m^3.At the same particle size,the explosion pressure firstly increases and then decreases with the increase of the mass concentration.There is a maximum explosion mass concentration,which makes the explosion pressure reach the maximum value.The explosion pressure of magnesium-aluminum alloy powder with the particle size of 502.2,293.6 and 59.8μm reaches the maximum at alloy powders mass concentration of1750 g/m^3.Besides,the limited oxygen volume fractions of magnesium-aluminum alloy powder are 15%,13% and 4% with particle sizes of 502.2,293.6 and 59.8μm at alloy powder mass concentration of 500 g/m^3.