Experiment study of characteristics of powder pneumatic filling
Experiment study of characteristics of powder pneumatic filling
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粉末气动灌装特性实验研究
DOI：
10.7498/aps.69.20191273
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发表时间：
2020
影响因子：
1
通讯作者：
Deng Zhe
中科院分区：
文献类型：
--
作者：
Yang Jian-Gang;Hu Chun-Bo;Zhu Xiao-Fei;Li Yue;Hu Xu;Deng Zhe
粉末发动机是一种具有多种点火能力和推力调节功能的新概念发动机。火药充填是火药发动机试验的重要环节。进行了粉末充填实验，考察了集粉箱的充填位置和流态化气体的质量流量对粉末充填稳定性和充填性能的影响。结果表明，较大的流态化气体流量有利于粉末充填的稳定性，但充填粉末的体积效率最低，仅为68.1%，而当流态化气体的质量流量较小时，体积效率为93.9%。与端盖垂直入口相比，圆筒壁切向入口使粉末的均匀性更好。在气动充填模式下，收集箱内的粉料体积密度大于粉仓内的粉料体积密度。此外，位置位移计算的粉末质量总是大于电子天平测量的粉末质量。这表明在粉末充填实验过程中，储罐内的粉末密度是不断变化的。用本文建立的模型计算了粉料槽内的实际堆积密度，发现当流态化气体的质量流量较低时，粉料在槽内的堆积密度是先增大后减小，最终堆积密度小于初始值。当流态化气体的质量流量较大时，储罐内的粉末堆积密度先增大后减小，最后增大后减小，最终堆积密度大于初始值。储罐内粉料体积密度的压缩机理类似于阻尼器弹簧振子在受迫振动时的运动规律。它可以用二阶系统的衰减响应函数来描述。当流态化气体的质量流量较小时，系统的阻尼系数较小。当流态化气体的质量流量较大时，其阻尼系数较大且是可变的。
Powder engine is one kind of new concept engines with multiple ignition capability and thrust modulation function. Powder filling is an important process of the powder engine tests. The powder pneumatic filling experiments were carried out to investigate the effects of the filling position of the powder collection box and the mass flow rate of fluidization gas on the stability and performance of powder pneumatic filling. It's found that large mass flow rate of fluidization gas contributes to stability of powder pneumatic filling, but its volume efficiency of powder filling is the lowest, only 68.1%, but it's 93.9% when the mass flow rate of fluidization gas is small. Compared with the vertical inlet of end cap, tangential inlet on the cylinder wall makes the powder uniformity better. In the pneumatic filling mode, the powder bulk density in the collection box is greater than the bulk density in the powder tank. In addition, the mass of powder calculated by position displacement is always larger than the mass of powder measured by the electronic balance. It indicates powder bulk density in tank is constantly changing during the powder pneumatic filling experiments. The actual powder bulk density in the powder tank is calculated by a model established in this paper, it's found that when the mass flow rate of fluidization gas is low, the bulk density of the powder in the tank is increased first and then decreased, and the final bulk density is less than the initial value. While the mass flow rate of fluidization gas is high, powder bulk density in the tank is first increased, then decreased, then increased and then decreased, and the final bulk density is greater than the initial value. The compression mechanism of powder bulk density in the tank is similar to the motion law of the damper spring vibrator when it is forced to vibrate. It can be described by the damped second-order system response function. When the mass flow rate of fluidization gas is small, the damping coefficient of the system is smaller. While the mass flow rate of fluidization gas is large, the damping coefficient is larger and is variable.