等离子喷涂过程数值计算与实验研究

应用流体控制方程、传热传质方程、粒子输运方程、Maxwell电磁场方程建立多场耦合数学模型,研究普通等离子喷枪内外的流场特性.计算中考虑等离子气体的电离与复合反应,以及非局域热平衡效应,在此基础上,采用新的三维模型分析气流中粉末颗粒的速度和温度分布,并与DPV2000诊断系统测量值进行对比,结果显示二者的相对误差小于10%.分析结果表明：颗粒的速度和温度在喷涂距离70～90 mm范围内同时达到最大,可选择此范围为最佳喷涂距离.颗粒的加热加速行为研究为其最终的沉积和扁平化奠定了基础,对工艺参数优化和喷枪结构优化提供理论指导.

Numerical analysis and experimental study of atmospheric plasma spray process

A multi-physic fields coupling mathematical model was established using fluid controlling equations, heat and mass transfer equations, species transport equations and Maxwell’s electromagnetic equations, to discuss the flow field characteristics inside and outside plasma gun. The ionization and recombination reactions, as well as the effect of non-local thermal equilibrium were taken into consideration to investigate the plasma flow. On this basis, the new three dimensional model was adopted to analysis the distribution of particles’ velocity and temperature. The relative error was less than 10% comparing with measured value by DPV2000 diagnosis system. In addition, both particles’ velocity and temperature achieved maximum at the distance of 70-90 mm, this range can be selected the best spraying distance. The analysis of flight particles in the plasma flow will lay the foundation for study particles’ deposition and flattening on substrate, and provide theoretical guidance for optimization of process parameters and gun structure.