Numerical and Experimental Comparison of Induction Thermal Plasma Characteristics between 0.5 MHz and 4 MHz
Numerical and Experimental Comparison of Induction Thermal Plasma Characteristics between 0.5 MHz and 4 MHz
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0.5 MHz 和 4 MHz 感应热等离子体特性的数值和实验比较
DOI：
10.1252/jcej.32.619
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发表时间：
1999
影响因子：
0.8
通讯作者：
Motofumi Tanaka
中科院分区：
文献类型：
--
作者：
M. Sakano;Takayuki Watanabe;Motofumi Tanaka
为了在工业应用中得到更广泛的应用，在大气压下产生更大、更稳定的射频等离子体是很重要的。施加频率与等离子炬的尺寸、温度、速度和物质浓度的分布密切相关。本文通过对比二维建模方法和在直径为80 mm的等离子体管中产生等离子体的观测结果，研究了0.5 MHz和4 MHz频率下氩氢等离子体的特性。利用SIMPLEC算法求解二维连续性方程、动量方程、能量方程和物种守恒方程，计算了射频热等离子体的流场、温度场和浓度场。在二维建模方法的基础上，通过求解麦克斯韦方程组对电磁场进行了分析。Ar-H2大气压等离子体在0.5 MHz频率和高达75 kW射频功率条件下成功工作。等离子体区域的观测由气冷CCD相机系统完成。较低的感应频率产生较长较窄的等离子体区域。时变磁场对等离子体的穿透深度，即趋肤深度，随频率的减小而增大。在较低的感应频率下，等离子体中的高温区域比在较高的感应频率下存在更多的内部。数值结果与实验结果定性一致，表明较低的感应频率产生的等离子体区域更长、更窄。感应频率的选择对于确定产生更大的射频等离子体的最佳火炬直径非常重要。
Generation of larger and more stable RF plasmas at atmospheric pressure is important in order for their more widespread adoption in industrial applications. The applied frequency is strongly related to the size of the plasma torch, and also to the distributions of temperature, velocity and species concentration. In this work, the results of the investigation of the characteristics in argon-hydrogen plasmas generated at frequencies of 0.5 MHz and 4 MHz are presented by comparing the two-dimensional modeling approach and the observations of the plasma generated in a 80-mm diameter plasma tube.The fields of flow, temperature and concentration of RF thermal plasmas have been calculated by solving the two-dimensional continuity, momentum, energy, and species conservation equations using a SIMPLEC algorithm. The electromagnetic (EM) fields have been analyzed by solving Maxwell’s equations on the basis of the two-dimensional modeling approach.An Ar-H2 atmospheric pressure plasma is successfully operated at 0.5 MHz frequency and up to 75 kW RF power condition. The observations of the plasma region are performed by an air-cooled CCD camera system. Lower induction frequency generates a longer and narrower plasma region.The penetration depth of the time-varying magnetic field into plasmas, namely skin depth, increases with a decrease in frequency. At lower induction frequency, the high temperature region in the plasma exists more inside than at higher induction frequency. Numerical and experimental results show good agreement qualitatively and indicate that lower induction frequency generates a longer and narrower plasma region. The choice of induction frequency is important in determining the optimum torch diameter for the generation of larger RF plasmas.