【摘要】 选用氯化钠为基体制备金属火灾超细干粉灭火剂。应用反溶剂法对其改性,使纳米疏水二氧化硅吸附在氯化钠晶体表面,其中分散剂为PEG-1000。结果表明,纳米疏水二氧化硅的添加有利于细化氯化钠颗粒,但过量的添加会起反作用,最佳用量为3 wt%左右,平均粒径为2.18μm。镁片灭火实验证明超细复合干粉的灭火性能明显好于传统氯化钠灭火剂(商用D类灭火剂),纳米疏水二氧化硅最佳添加量为3 wt%,此时灭火时间仅需传统灭火剂的一半。最后利用FDS5.0模拟干粉颗粒与燃烧火焰作用过程,模拟结果表明干粉覆盖对火焰具有一定的抑制效果,并分析了复合干粉灭火机理。更多还原

【Abstract】 Sodium chloride was used as the matrix to prepare superfine dry powder fire extinguishing agent for metal fire and the nano-hydrophobic silica was adsorbed on the surface of sodium chloride crystals with anti-solvent method, where in the dispersant was PEG-1000. The results showed that the addition of nano-hydrophobic silica was beneficial to the dispersion and refinement of particles, but the excessive addition would be counterproductive. The optimum dosage was about 3 wt%, and the average particle size was 2.18 μm. Magnesium tablets fire extinguishing experiments were conducted to prove that the fire extinguishing performance of ultrafine composite dry powder was obviously better than that of traditional sodium chloride fire extinguishing agent(commercial D-type fire extinguishing agent), and the optimal content of nano-hydrophobic silica was 3 wt%, and The fire extinguishing time was only half of the traditional extinguishing agent. Finally, FDS5.0 was used to simulate the interaction between dry powder particles and combustion flame. The simulation results showed that the dry powder coating had a certain inhibition effect on the flame, and the mechanism of the composite dry powder fire extinguishing was analyzed.更多还原