等离子旋转电极雾化熔滴的热量传输与凝固行为

建立了在等离子旋转电极雾化 (PREP)制取合金粉末的过程中雾化熔滴的轨道运动方程 ,讨论了雾化熔滴在凝固过程中的热量传输与凝固行为 ,并确定了定量计算换热系数所需的雾化熔滴初始速度。用数值求解方法计算了FGH95高温合金雾化熔滴在PREP过程中的速度及其在凝固过程中的温度、固相分数、冷却速率等凝固参数。结果表明 :在作者提出的工艺参数下 ,FGH95合金熔滴的冷却速率达 10 4 K/s量级以上 ,合金过热度对冷却速率的影响主要在全液态阶段 ,而冷却速率和固相分数对氩氦气体的混合比例极其敏感

Heat transfer and solidification behavior of droplets during plasma rotating electrode processing

A mathematical model to describe flight trace of droplets atomized by plasma rotating electrode processing PREP was established, and the heat transfer and solidification behavior of the droplets during PREP discussed was based on Newtonian heat transfer formulation coupled with the classical heterogeneous nucleation. With the application of the differential method of Newton fluid dynamics, the initial velocities of droplets correlated to the heat transfer coefficients were determined. Using numerical method, the droplet velocity, droplet temperature, and fractional solidification with flight time about FGH95 superalloy droplet were predicted based on mathematical model. The results show that the cooling rate of FGH95 superalloy droplet reaches above 10 4 K/s order of magnitude, and the effect of droplet superheat taking on the droplet solidification behavior is mainly in the fully liquid stage, while the cooling rate of the droplet is sensitive to the proportion of mixed cooling gas.