气流粉碎/静电分散中粉体颗粒运动规律的数值模拟研究

通过经典力学及流体力学基本原理,建立轨道模型对气流粉碎/静电分散相复合制备超微粉体中粉碎分散仓内颗粒的运动过程进行了数值模拟研究,揭示了气流粉碎/静电分散过程中粉体颗粒的运动规律。当荷电电压为20 k V,射流速度较低时粉体颗粒流存在准稳态层流流动现象;随着射流速度的提高,粉体颗粒转变为弥散分布,且分散性具有一定程度的提高;当荷电电压增大至60 k V时,仓内粉体颗粒的分散性有了进一步的提高,呈现出较好的均匀分散状态。研究结果表明,增大射流速度和荷电电压能够有效的提高制备过程中粉体颗粒的分散性,且后者效果更为明显。

Numerical Simulation of the Dynamic Process of Micropowder during Jet Milling/Electrostatic Dispersion

Based on?the?fundamental?principle?of?classical mechanics?and?hydromechanics,?a particle-trajectory?model?was?established to simulate transport process?of?particles?in?J/E?chamber?during the?preparation?of?micropowder with a combination of jet milling and electrostatic dispersion techniques,?and?the law of kinetic?of the particles during?J/E?process?was revealed?as well.?When the charging voltage is?20 kV, the?grain flows?of micropowder present?laminar?flows of?quasi-steady-state?as?the?velocity of jet is low.?With the increase of jet velocity, the distribution of particles?transforms?into?dispersive?state,?and?the dispersion enhances to a certain extent. While when the charging voltage increases to 60 kV,?the dispersion of particles in the chamber?is further improved, which presents?a better evenly dispersed state.?The simulation of flow dynamics of the particles shows that?increasing the jet velocity and the charging voltage can improve?the dispersiveness of the powder during the transport process in?the?J/E?chamber, and the effect of the charging voltage is more?substantial.