面向等离子熔射成形技术的粉末飞行特性数值分析

粉末在射流场中飞行特性是影响熔射成形件质量的重要因素。通过所建立的粉末与射流相互作用的动量和能量传递方程，应用有限差分法，模拟计算和分析了粉末速度与温度分布规律及其对成形件质量的影响。结果表明：①粒径及密度越小，加(减)速度越快，而到达原模时的速度则不同；②热传导性越差，粒径越大，极值温度则越小，且逐渐向原模方向偏移；③粉末的力学行为和加热特性的匹配，可进一步提高熔射成形件质量。模拟结果为实现熔射成形质量控制及参数优化，提供了理论依据。

Numerical Analysis of In-Flight Behavior of Particle in Plasma Spray Forming

In-flight behavior of particle in plasma jet is one of important factors, which affect the quality of workpiece formed by plasma spraying. Through the momentum and energy transfer equation established by the theory of particle-plasma interaction in plasma jet, the laws of velocity and temperature field have been simulately calculated by the finite difference method to analyze their effect on the quality of plasma spray forming (PSF). The results show that: (1) The acceleration of particle increases with the decreasing of diameter and density, but its velocity arriving the prototype is different. (2) If the diameter of particle is bigger, and its heat conductibility is poorer, its extremum temperature is lower, and the extremum point is shifted to the prototype gradually. (3) By matching the mechanical behaviors with heating characteristics, the quality of PSF is further improved. The computational results provide the basic theory to realize the quality control and parametersoptimization in PSF.