基于COMSOL 的感应耦合等离子体炬多物理场研究

为了优化锂微粉等离子体球化的工艺，对感应耦合等离子体炬进行二维建模，将电磁场计算域扩展到等离子体放电区域之外的空气区域，利用COMSOL 软件进行多物理场模拟。得到了等离子体的电磁场、温度和速度分布，并对分布形成的物理机制进行分析。模拟发现等离子体区域线圈段存在上下两组对称的回流涡，线圈段中部靠近约束管处等离子体速度分布杂乱，有激烈的径向打壁现象，乱流预计会对约束管壁相应位置造成一条环状的破裂效果。基于模拟结果，提出在采用感应耦合等离子体球化锂微粉的工艺工程中，可以将注粉口下移，绕开上回流涡。

Multi-physics simulation of inductively coupled plasma torch based on COMSOL

In order to optimize the process of plasma spheroidization of the lithium micro-powder, a 2-D model of inductively coupled thermal plasma torch is presented. The calculating domain of the electromagnetic field is extended to the air region outside the plasma discharge region and multi-physics coupling calculation was performed by using COMSOL software. The plasma electromagnetic field, temperature and velocity distributions are obtained. The physical mechanism of distributions is analyzed. The simulation found that there are two sets of symmetrical reflux vortices in the coil section of the plasma region. The velocity distribution which locates in the center of coil section and closes to the wall of confinement tube is in disorder. The plasma particles hit the wall along the radial direction. Disorderly flow may cause a rupture area along the circular tube wall. Based on the simulation results, it is proposed that in the process of inductively coupled plasma spheroidization, powder injection port can be moved down to avoid the upper reflux vortex.