摘要
为了提升等离子体应用效果,必须对等离子体的放电动力学过程进行深入探讨。转动温度是反映等离子体放电过程中能量输运的重要参数之一,目前主要采用波尔茨曼斜率法计算,该方法常用于计算热力平衡状态下等离子体的转动温度,在计算非热力平衡状态下的等离子体转动温度时误差较大。针对这一问题,提出了利用双原子分子谱带计算转动温度的分析方法,采用针-环式电极等离子体射流装置进行试验,向装置中通入Ar/Air/CH_(4)混合气体放电形成等离子体射流,工作电压为10~14 kV,利用光谱仪采集不同放电电压下的等离子体射流的光谱数据用以计算转动温度。选择OH(A—X)、CH(A—X)以及N_(2)^(+)(B—X)发射光谱,利用三种双原子分子波长区间内谱线不受振动温度变化所影响的特性,对Ar/Air/CH_(4)等离子体射流的转动温度进行研究。在波尔茨曼斜率法计算得到转动温度±100 K范围内每20 K选取谱线,与试验谱线进行拟合,计算谱线拟合得到的均方根误差,分析拟合准确度,得到更为准确的介质阻挡放电(DBD)激励Ar/Air/CH_(4)等离子射流的转动温度。波尔茨曼斜率法计算出的转动温度在拟合时得到的均方根误差要高于最小均方根误差,均方根误差能够减小38%。利用OH、CH、N_(2)^(+)谱带拟合得到最小均方根误差分别为4.6、2.9、2.1,N_(2)^(+)谱带拟合结果比OH谱带的拟合结果均方根误差减小61%。结果表明,在计算非热力平衡状态等离子体的转动温度时,相比于波尔茨曼斜率法,计算谱线拟合均方根误差的的方法能够有效地提升计算结果的准确度,在进行谱线拟合时选择N_(2)^(+)(B—X)谱带的发射光谱与试验谱线进行拟合能够进一步提升计算结果的准确度。
To enhance plasma applications'effect,plasma's discharge kinetic process must be explored in depth.The rotation temperature is one of the important parameters reflecting the energy transport in the plasma discharge process,which is mainly calculated by the Boltzmann slope method,which is commonly used to calculate the rotation temperature of the plasma in the thermodynamic equilibrium state and has a large error in calculating the rotation temperature of the plasma in the non-thermal equilibrium state.To address this problem,this thesis proposes an analytical method to calculate the rotation temperature using diatomic molecular spectral bands.A needle-ring electrode plasma jet device is used for the experiment,and a plasma jet is formed by discharging a mixture of Ar/Air/CH_(4)gas into the device with an operating voltage of 10~14 kV.A spectrometer collects the spectral data of the plasma jet at different discharge voltages to calculate the rotation temperature.The OH(A—X),CH(A—X)and N_(2)^(+)(B—X)emission spectra were selected to investigate the rotation temperature of the Ar/Air/CH_(4)plasma jet,using the property that the spectral lines in the wavelength interval of the three diatomic molecules,are not affected by the change of vibration temperature.The rotation temperature of the DBD-excited Ar/Air/CH_(4)plasma jet was obtained by selecting one spectral line every 20 K in the range of±100 K calculated by the Boltzmann slope method,fitting it to the experimental spectral line,calculating the root-mean-square error obtained from the fit of the spectral line,and analyzing the accuracy of the fit.The root-mean-square error of the rotation temperature,calculated by the Boltzmann slope method obtained in the fit,is higher than the minimum root-mean-square error,and the root-mean-square error can be reduced by 38%.The minimum root-mean-square errors obtained by fitting the OH,CH,and N_(2)^(+)spectral bands were 4.6,2.9,and 2.1,respectively,and the results of fitting the N_(2)^(+)band were 61%lower than the results of fitting the OH band.The results show that calculating the root-mean-square error of spectral line fitting can effectively improve the accuracy of the calculation results,compared with the Boltzmann slope method when calculating the rotation temperature of the plasma in the non-thermal equilibrium state.The accuracy of the calculation results can be further improved by choosing the emission spectrum of the N_(2)^(+)(B—X)band for fitting to the experimental spectral line.
作者
张文钧
宋鹏
鞠迎昕
关婷予
纪相彤
韩朋
ZHANG Wen-jun;SONG Peng;JU Ying-xin;GUAN Ting-yu;JI Xiang-tong;HAN Peng(College of Mechanical and Electronic Engineering,Dalian Minzu University,Dalian 116605,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2024年第11期3136-3141,共6页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金青年科学基金项目(51409158,51509035)
航空动力基金项目(6141B090540)资助。
关键词
介质阻挡放电
等离子体射流
发射光谱
转动温度
Dielectric barrier discharge
Plasma jet
Emission spectrum
Rotation temperature
