Study on Dust Explosion Characteristics and Flame Propagation of Nano-Sized Aluminum Powders

This study is mainly to explore the dust explosion characteristics and flame propagation of nano-sized aluminum (Al) powder. First of all, three kinds of A1 powders with average particle sizes of 35, 75 and 100 nm were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) to confirm the particle size and purity. An environment operation box was used to avoid the oxidation of nano-sized Al powder samples during the weighing process. Afterward, the 20-L explosion sphere apparatus was used to determine the dust explosion characteristics, including the maximum explosion pressure (P_(max)), maximum rate of pressure rise [(dP/dt)_(max)], minimum explosion concentration (MEC) and deflagration index (K_(st)), and the modified Hartmann tube was used to evaluate the minimum ignition energy (MIE) and flame propagation velocity (FPV). The experimental results indicated that the maximum P_(max), (dP/dt)_(max) and K_(st) values increased with decreasing average particle size of nano-sized Al powder, and the MEC and MIE values increased with increasing average particle size of nano-sized Al powder. In addition, the maximum flame propagation velocity (FPV) of nano-sized Al powder increased with decreasing particle size, and decreased with increasing ignition energy used. According to the dust explosion class, these three nano-sized Al powders were classified as Class 3, which means that they have very strong explosive power.

關鍵字

nano-sized aluminum powder ； dust explosion characteristics ； flame propagation

並列摘要

本研究旨在探討奈米級鋁粉的粉塵爆炸及火焰傳播特性，首先藉由掃描式電子顯微鏡確認平均粒徑分別為35、75和100 nm三種尺寸的奈米鋁粉；實驗使用20公升爆炸鋼球量測粉塵爆炸特性，包括最大爆炸壓力（Pmax）、最大升壓速率[(dP/dt)max]、最小爆炸濃度（MEC）及爆燃指數（KSt），並使用改良的Hartmann管評估最小點火能量（MIE）和火焰傳播速度（FPV）。實驗結果顯示Pmax、（dP/dt）max和KSt與鋁粉粒徑成反比，而MEC和MIE則與鋁粉粒徑成正比。此外，鋁粉最FPV值隨著粒徑減小而增加，並隨著所使用點火能量增加而減小。根據粉塵爆炸等級分類，這三種奈米級鋁粉被歸類為第3級，顯示它們具有很強的爆炸特性。

並列關鍵字

奈米級鋁粉；粉塵爆炸特性；火焰傳播

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