| Aluminum and aluminium alloy powder are important metal materials in industry,but their main components are active and easy to react with other substances,including combustion explosion reaction.Therefore,in order to prevent,control and reduce the damage caused by the explosion of aluminum powder and aluminum alloy powder,it is necessary to study the rules of combustion and explosion of aluminum and aluminum alloy powder.In this paper,firstly,the physical and chemical properties and morphology characteristics of aluminum powder and aluminium-silicon alloy powder are analyzed,including particle size distribution,element composition and apparent morphology of particles.Secondly,the effects of dust particle size and dust cloud concentration on the minimum ignition temperature of dust cloud and the initial ignition energy were studied by using HY16429 type dust cloud ignition temperature test device and 20 L near-spherical explosion test system.The effects of particle size and concentration of dust cloud on the explosion characteristics of dust were studied.The lower limit of explosion of aluminum powder and aluminum-silicon alloy powder under different conditions was tested.Finally,the explosion characteristics of aluminum powder and aluminum-silicon alloy powder were compared and analyzed.The results show that the minimum ignition temperature of aluminum powder and aluminum-silicon alloy powder dust cloud increases obviously with the increase of dust particle size.However,when the particle size of the dust increases to a certain extent,no combustion occurs in the dust cloud of aluminum powder or aluminum-silicon alloy powder.When the concentration of dust cloud is within a certain range,the minimum ignition temperature of aluminum powder and aluminum-silicon alloy powder dust cloud decreases first and then rises.The existence of dust cloud sensitive concentration makes the minimum ignition temperature of dust cloud reach the minimum value,and the danger is the highest.There is a numerical difference in the ignition sensitive concentration of dust cloud due to the inconsistency of dust particle size.The minimum ignition temperature of aluminum powder and aluminum silicon alloy powder is similar,but the lowest ignition temperature is different between them under the same conditions,and the minimum ignition temperature value of aluminum silicon alloy powder is lower than that of aluminum powder.When the initial ignition energy is in the range of 1?10 kJ,the maximum explosion pressure and the maximum explosion pressure rise rate of aluminum powder and aluminum-silicon alloy powder increase gradually,and the aluminum powder is larger than the Al-Si alloy powder under the same conditions.All the aluminum powders with different particle sizes were exploded at 1?10 kJ ignition energy,but only when the initial ignition energy was greater than or equal to the minimum initial ignition energy.The maximum explosion pressure of aluminum powder and aluminum-silicon alloy powder decreased with the increase of dust particle size,but the maximum explosion pressure of aluminum powder was obviously larger than that of Al-Si alloy powder.The maximum explosion pressure and the maximum explosion pressure rise rate of aluminum powder and aluminum-silicon alloy powder show a peak with the increase of dust cloud concentration(maximum value,maximum explosion pressure)corresponding to its most violent explosion concentration.The smaller the particle size,the lower the maximum explosive concentration and the lower explosion limit.Under the same conditions,the most violent explosion concentration and the lower explosion limit of aluminum powder are lower than that of aluminum silicon alloy powder,and it is easier to explode.The explosive characteristics of aluminum-silicon alloy powder are similar to that of aluminum powder,but the reaction of aluminum powder is rapid,and the explosion intensity is stronger than that of aluminum silicon alloy powder. |
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