三维等离子体射流中空气的卷吸和粒子的氧化

为了研究等离子体射流中空气的卷吸和由此引起的金属粒子的氧化，建立了等离子体喷涂的三维计算机模型LAVA-P-3D.喷涂系统采用氩 氢混合气的直流电等离子体，粒子材料是钼.三维模型通过求解等离子射流的N-S方程得出混合气体的温度、速度和氧气浓度等的分布，其中考虑了粒子与等离子射流的相互作用.粒子的模拟采取了轨迹追踪法，研究了粒子的加速、传热、熔化和氧化等物理现象.等离子体射流的模拟结果与实验结果相吻合，并且用数值模拟研究了不同大小粒子的温度、速度、和氧的质量分数.研究结果表明，粒子越大，温度、速度和氧质量分数越小；粒子的氧化量随飞行距离的增长而线性增加.

Three-dimensional simulation of air entrainment in plasma jet and particle oxidation

Air entrainment in plasma jet and metal particle oxidation by the entrained oxygen were investigated numerically using a three-dimensional computational model LAVA-P-3D.A DC plasma spray was studied with Ar-H_2 gas mixture and Mo particles.The N-S(Navier-Stokes) equations of the plasma jet were solved to calculate the gas temperature,velocity and oxygen entrainment.The in-flight particles were treated as Lagrangian entities,considering particle accelerating,heating, melting and oxidation.The experimental data on the plasma jet are presented to compare with the simulation results,showing good agreement had been achieved.The temperature,velocity and oxide content of different size particles were studied.The results show that the large particles have small velocity,temperature,and oxide content.