射频热等离子体制备球形氧化铝粉末的数值模拟及实验研究

研究粉末颗粒在热等离子体(ICTP)中的行为可以为射频等离子体制备球形粉末工艺过程的优化提供参考。首先, 利用FLUENT软件对具有不同粒径分布的氧化铝粉末颗粒在射频热等离子体中的运动轨迹及加热历程进行了数值模拟; 然后, 根据模拟结果所确定的实验参数范围进行了射频热等离子体粉末球化实验, 并将实验测量与数值模拟的结果相结合, 研究了输入功率、送粉速率等参数的改变对具有不同粒径分布的氧化铝粉末球化效果的影响。研究结果表明: 粒径较小的氧化铝粉末颗粒在飞行过程中可以从等离子体内吸收更多的热量, 因此能够被充分加热至完全熔化; 增加系统输入功率、降低送粉速率均能提高单位质量的颗粒从等离子体中获得的能量, 从而在一定程度上提升氧化铝粉末的球化率。

Preparation of Spherical Alumina Powder by RF Thermal Plasma: Numerical Simulation and Experimentation

Behavior of alumina powder particles in inductively coupled thermal plasma (ICTP) can provide theoretical reference and guidelines for improving preparation process of plasma spheroidization. In this study, the motion trajectories and heating process of alumina powder particles in ICTP were investigated by means of numerical simulation with FLUENT software. Then the plasma spheroidization experiment was carried out on the basis of simulation results, and the effect of input power, powder feeder rate and particle size distribution on alumina powder spheroidization were studied by combination of experimental and the theoretical analyses. The results show that the small particles absorb enough heat from thermal plasma and therefore be heated to completely melt. Furthermore, the particle can get more energy from plasma while the input power of system is increased or the powder feeder rate is decreased, which improve the spheroidization effect of alumina powder particles.