Research of Filling Ratio and Fluidization Performance of Dense-Packing Aluminum Powder

铝粉致密装填率及其流化性能研究

¹ School of Aerospace, Northwestern Polytechnical University, Xi’an 710072, China
² Xi'an Modern Chemistry Research Institute, Xi’an 710065, China

Received: 12 March 2018

Abstract

Based on the granule packing theory, grading vibrating filling experiments have been carried out for aluminum powder with different particle sizes. The effects of the several factors on the dense filling ratio of aluminum powder, such as filling craft, vibration time and grading parameter, have been discussed. The distribution uniformity of particle size and fluidization performance of the dense-packing aluminum powder have been detected and analyzed. The results show that the powder filling ratio can be improved greatly by performing the batch packing, stirring and vibrating on powder. The initial vibration can improve the powder filling ratio obviously, but the ascension is not obvious with the increasing of vibration time. The selection of grading parameter should ensure that the small particles can fill in the gaps among large particles. The filling ratio as high as 73.02% has been obtained under the grading parameter m_{100 μm}:m_15μm:m_1μm=6.89:2.97:1. The testing results show that the size uniformity of aluminum powder obtained by this filling craft is good at the same height, but need to be improved at different heights. The fluidization performance of dense-packing aluminum is good, and the accuracy of powder supply reaches 3.6%, which can meet the requirement of powder supply in powder rocket engine.

摘要

以颗粒堆积理论为基础，对不同粒径的铝粉进行级配振实装填实验研究，探讨了装填工艺、振动时间和级配参数对铝粉致密装填率的影响，并对致密装填所得的铝粉粒径分布均匀性及粉末流化性进行了实验检测分析。结果表明，对粉体进行分批装填、搅拌和振动，可以极大地提高粉体装填率；初期的振动对装填率提升比较明显，随着振动时间的逐渐加长，装填率提升增益将逐渐减小；级配参数的选取应尽量保证小颗粒能填满大颗粒间形成的空隙，最终在m_{100 μm}：m_{15 μm}：m_{1 μm}=6.89：2.97：1的级配参数下获得了高达73.02%的致密装填率；检测分析结果表明该装填工艺所得铝粉在同一高度处均匀性良好，不同高度处均匀性还有待改善，致密装填所得铝粉的流化性能良好，且粉末供给精度达到了3.6%，可以满足粉末火箭发动机供粉要求。