低压直流电弧等离子体传热与流动的数值模拟

Numerical Simulation for Heat Transfer and Flow of Plasma in LPPS

根据低压等离子体喷涂所使用的F4-VB喷枪结构,建立了三维稳态湍流模型,采用Fluent软件对104 Pa低压条件下等离子体喷涂过程中等离子体的温度、速度和压强分布进行了模拟。结果表明:阴极尖端附近的等离子体温度达到最高值29 000K,随后温度降低。等离子体速度在喷枪内急速上升,离开喷枪出口约0.01m时达到最大值6 100m/s,随后速度降低。等离子体在距离喷枪出口附近约0.07m以内经历了膨胀和压缩过程,等离子体的膨胀和压缩对速度和温度的变化有显著影响。

According to the structure of low pressure plasma spray gun F4-VB, a three-dimensional, and steady, tur- bulent model was established. Computational fluid dynamic software Fluent was adopted in this study. The research mainly involves the temperature, pressure and velocity distribution inside the argon plasma torch under the pressure of 104 Pa in the argon environment. The results show that the plasma temperature reaches the highest value near the tip of the cathode at 29 000 K and then the temperature drops gradually. The plasma velocity rises rapidly inside the torch, reaching the highest value of 6 100 m/s after leaving a distance of 0.01 m from the exit and then drops slowly. Within a distance of 0. 07 m from the plasma gun exit, plasma undergoes significant expansion and compression that obviously af- fect the tendency of velocity and temperature.