超音速等离子喷涂过程颗粒运动特性（英文）

Particle movement characteristics of supersonic plasma spraying process

在对等离子喷涂多物理场特性分析的基础上,考虑拖曳力、热泳力、压力梯度力等受力,对颗粒的运动特性进行研究。利用SprayWatch-2i对飞行颗粒进行在线监测并与计算值进行对比。结果表明:距喷嘴出口90~100 mm是超音速等离子喷涂的最佳喷涂距离。超音速等离子喷涂颗粒所受气流的拖拽力要大于普通等离子喷涂。当距离喷嘴出口90 mm处时,颗粒的最低温度达到3800 K,已高于Al_2O_3的熔点,此时颗粒已完全熔化。颗粒在等离子射流中发生细化,在距离喷嘴出口100 mm处直径小于5μm的颗粒所占比例超过了50%,颗粒主要发生的是振动破碎。通过实验验证了超音速等离子喷涂数值模拟的正确性。

Based on the analysis of characteristics of plasma spraying multi-physics fields,considering the drag force,thermophoretic force,pressure gradient force,the particle movement characteristics during the plasma spraying process were studied. The flying particles were monitored on-line by SprayWatch-2i software and compared with the calculated values. The results show that the optimal spraying distance of supersonic plasma spraying is 90-100 mm from the exit of the nozzle. The drag force of supersonic plasma spraying particles is greater than that of atmospheric plasma spraying. The minimum temperature of the particles reaches 3800 K at 90 mm away from the nozzle exit,which is higher than the melting point of Al2O3,so the particles are completely melted at this place. The particles are refined in the supersonic plasma spraying process,and the particles with diameters less than 5 μm are more than 50% at 100 mm away from the nozzle exit,which is because vibration crushing occurs in the particles. The validity of numerical simulation of supersonic plasma spraying has been validated by experiments.