KF对微米铝粉在水蒸气中着火燃烧特性的影响

为改善微米铝粉在水蒸气中的着火特性和燃烧效率，采用自行设计的管式炉实验平台研究了KF对30 ?m铝粉在1000℃水蒸气中着火燃烧特性的影响。用高速摄影系统记录了样品着火燃烧过程，并通过X射线衍射、扫描电镜技术和化学分析方法分析了产物组分、形貌和燃烧效率。结果表明，加入KF可显著降低30 ?m铝粉的点火延迟时间，与加入5wt% (0.003 g) KF相比，加入15wt% (0.009 g) KF后，样品的点火延迟时间减少了47.58 s；微米铝粉在1000℃水蒸气中不能着火，加入KF后能着火，这是因为KF与水蒸气反应生成KOH，KOH与Al2O3反应会破坏铝粉的氧化壳，加快铝与水蒸气的反应，促进铝粉着火。随KF加入量提高，样品的燃烧效率显著上升，最高为82.24%，比未添加KF样品的燃烧效率提升了38.75%。提高KF加入量，可产生更多的KOH，对氧化壳的破坏效果更显著，进一步促进铝与水蒸气反应，提高铝粉燃烧效率。

Effect of KF on the ignition and combustion characteristics of micron-sized aluminum powder in water vapor

Ignition difficulty and poor combustion efficiency are the disadvantages of micron-sized aluminum powder in application. To improve the ignition and combustion characteristics of micron-sized aluminum powder in water vapor, a homemade pipe furnace experimental platform was established to study the effects of potassium fluoride (KF) on ignition and combustion characteristics of 30 ?m aluminum powder in water vapor at 1000℃ in this work. The high-speed photographic system was used to record the ignition and combustion process of various samples. The product components, product morphology, and combustion efficiency were analyzed by X-ray diffraction, scanning electron microscopy and chemical analysis method, respectively. The results showed that the potassium fluoride addition into 30 ?m aluminum powder significantly decreased its ignition delay time. Compared with the aluminum powder with potassium fluoride addition of 5wt% (0.003 g), the ignition delay time of the aluminum powder decreased by 47.58 s than that of 15wt% (0.009 g). Pure aluminum powder cannot be ignited in water vapor at 1000℃, and the aluminum powder with potassium fluoride addition can be ignited. Because potassium fluoride reacted with water vapor to form KOH, which can react with Al2O3 to destroy the oxidation shell of aluminum powder, thereby accelerating the reaction between aluminum and water vapor, and promoting the ignition of aluminum powder. Moreover, the combustion efficiency of aluminum powder with addition of potassium fluoride increased considerably with the increase the potassium fluoride contents, and its highest combustion efficiency was 82.24%, which was 38.75% higher than that of the aluminum powder without potassium fluoride addition. The increase of potassium fluoride content can produce more KOH, which increased the damage effect on the oxide film and promoted the reaction of aluminum with water vapor, thereby improving the combustion efficiency of the aluminum powder.