Determination of Spectroscopic Temperatures and Electron Density in Rotating Gliding Arc Discharge

Abstract

The spectroscopic characteristics of rotating gliding arc (RGA) discharge, codriven by a magnetic field and tangential gas flow, have been investigated by optical emission spectroscopy. In argon gas, the electron density of the atmospheric RGA plasma was measured, while the vibrotatinoal temperatures were measured in nitrogen discharge. By simulating the spectral line profile determined by the joint effects of Lorentzian (Stark, van der Waals, and natural) and Gaussian (Doppler and instrumental) broadening, the electron density fluctuated in the range of 1.32×10 15 -4.56×10 15 cm −3 and 4.06×10 15 -5.74×10 15 cm −3 within the variation of argon flow rate and applied voltage, respectively. The rotational temperature in N 2 discharge was obtained by comparing the modeled optical emission spectrum with the experimental measurements. The vibrational temperature was derived from a Boltzmann plot by analyzing the spectral bands of the second positive system of N 2 (C 3 u → B 3 g ). The vibrational and rotational temperatures varied in the range of 0.1-0.13 eV and 0.42-0.44 eV, respectively, under the same operating condition, indicating that the RGA discharge is a nonequilibrium plasma. By analyzing the fundamental spectroscopic parameters of the discharge, a comprehensive understanding of RGA plasma was achieved, facilitating its application in practical industry processes.Index Terms-Electron density, plasma, rotating gliding arc (RGA), rotational temperature, vibrational temperature.

Experimental and simulation investigation of electrical and plasma parameters in a low pressure inductively coupled argon plasma

“…Versatile spectroscopic information could be obtained by OES. The intensity of spectral lines I nm describes the transition from upper energy level n to lower energy level m, is regarded as a qualitative indicator of species number density [11,20].…”

“…where K nm is a factor related to plasma volume, nm l is the wavelength of transition, n n is the number density at upper level, h is Plank's constant, c is the speed of light, and A nm is emission probability of the transition. The variation of I nm reveals the evolution of the population of related argon species number density through collisional-radiative model with the kinetic reactions as follows [11,21].…”

“…where w G is contributed by Doppler broadening (w D ) and instrumental broadening (w in ), and w L is constituted by Stark broadening (w S ) and Van del Waals broadening (w v ). The plasma temperature and electron could be obtained through formulas (5) and (6), whereas the detailed mechanism and calculation method in [11,23,24] will not be elaborated here:…”

“…Khan et al comparatively studied the T exc and T e in E and H modes of ICPs, and indicated similar variation trend of T exc and T e with applied power and argon pressure [9]. Electron density n e is calculated by fitting the shape of selected spectral line configuration, which always results in a Voigt profile contributed by convolution of Gaussian broadening (Doppler broadening and instrumental broadening) and Lorentz broadening (Van der Waals broadening and Stark broadening) [10,11]. By resolving the Lorentz broadening, electron density n e could be obtained [12].…”

Experimental study on gliding discharge mode of rotating gliding arc discharge plasma

“…此外, 研究人员还开展了二维刀型电极滑动弧的二 维(2D)和三维(3D)数值模拟研究, 讨论了滑动弧 放电中的击穿发生机制, 并研究了电弧在高电流和 低电流条件下运动过程的传热机制的差异 [21,22] . 上 Ananthanarasimhan等 [23] 发现气体流量、雷诺数 影响旋转滑动弧动力学特征, 尤其是对电弧旋转频 率以及放电电压波形影响较大. Wu等 [24] 对滑动 弧放电进行了光谱测量, 计算了旋转滑动弧的电子 密度、振动温度, 证实了旋转滑动弧的非平衡等离 子体特征, 并发现随着气体流速增加, 振动温度先 升高后降低.…”