数值模拟感应耦合氩气热等离子体温度和速度的空间分布

Numerical Simulation of the Temperature and Velocity's Spatial Distributions of Inductively Coupled Argon Thermal Plasma

研究感应耦合热等离子体的温度和速度的空间分布对等离子体球化、合成粉末材料过程等实际应用具有非常重要的理论指导意义。为此,首先介绍了利用FLUENT模拟感应耦合热等离子体的仿真方法,在此基础上计算得到了氩气热等离子体温度和速度的空间分布及其基本特点,并研究了工作气体体积流量和少量氢气的加入对温度和速度空间分布的影响。研究结果表明:改变反应气体积流量对等离子体温度和速度的空间分布无明显影响;但增大冷却气体积流量可大大降低炬边缘的温度。氢气的加入对等离子体温度和速度的空间分布的影响较大,将使等离子体弧区更加集中,速度变小,回流区变大;分析认为这是因为氢气的加入改变了等离子体的比热容和电导率等参数。

Studies on spatial distributions of temperature and velocity of inductively coupled thermal plasma can provide valuable theoretical guidelines for practical applications of plasma spheroidization,synthetic process of powder materials.Therefore,we introduced a method for simulating inductively coupled thermal plasma by FLUENT firstly.Using the method,we calculated the spatial distributions and their basic characteristics of argon thermal plasma.Moreover,we studied the influence of working gas volume flow and addition of hydrogen on the spatial distributions.The research results show that,changing the reaction gas volume flow has no significant effect on the two distributions.However,increasing the sheath gas volume flow can greatly reduce the temperature on the edge of torch.Moreover,adding hydrogen gas in the plasma can change the spatial distributions greatly： the plasma arc becomes more focused,the plasma velocity becomes smaller,and the reflow area becomes bigger.It is concluded that the changes happens probably due to the changes in specific heat capacity and electric conductivity of the plasma by adding hydrogen.