Net emission coefficients of argon iron plasmas with electron Stark widths scaled to experiments
Net emission coefficients of argon iron plasmas with electron Stark widths scaled to experiments
复制标题
电子斯塔克宽度按实验比例缩放的氩铁等离子体的净发射系数
DOI：
10.1088/0022-3727/44/12/125201
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
M. Wendt
中科院分区：
文献类型：
--
作者：
M. Wendt
计算和分析了圆柱几何情况下大气压下含Ar和Fe的等离子体的净发射系数。它的值是通过对考虑连续辐射和线辐射的单色净辐射系数进行积分而获得的。谱线的宽度由多普勒展宽、自然展宽、共振展宽、范德华展宽、电子和离子斯塔克展宽决定。由于在所考虑的压力和温度范围内，斯塔克展宽是最重要的展宽机制，因此根据半经验斯塔克展宽理论计算了电子的斯塔克展宽。此外，将Ar、Ar+、Fe和Fe+的电子斯塔克宽度乘以比例因子，以重现实验的电子斯塔克宽度。每个物种的比例因子都是单独确定的。对于较小的等离子体半径，所测得的净辐射系数与文献值符合得很好，其中考虑了球面几何形状，但随着等离子体半径的增大，净辐射系数下降得更快。这是由于当考虑柱面几何而不是球面几何时，对称轴的照射增加所致。对于气体保护焊过程中出现的弧芯的典型半径和温度，即半径在1到2×10−3 m之间，温度在5 000到10 000 K之间，斯塔克宽度的缩放使铁等离子体的净发射系数增加了2%到23%。在此参数范围内，圆柱形等离子体的净发射系数比球面等离子体的计算值小30%到37%。
The net emission coefficient of plasmas containing argon and iron at atmospheric pressure is calculated and analysed for the case of cylindrical geometry. Its values are obtained by integrating the monochromatic net emission coefficient taking into account continuous and line radiation. The width of the spectral lines is determined by Doppler broadening, natural, resonance, van der Waals, electron and ion Stark broadening. As Stark broadening is the most important broadening mechanism in the considered pressure and temperature range, the electron Stark widths are calculated following the semi-empirical Stark broadening theory. Additionally, the electron Stark widths of Ar, Ar+, Fe and Fe+ are multiplied by scaling factors in order to reproduce experimental electron Stark widths. The scaling factor is determined for each species separately. For small plasma radii the net emission coefficient determined here shows good agreement with literature values where spherical geometry is considered while they decrease faster with increasing plasma radius. This behaviour is caused by the increase of the irradiation of the symmetry axis when cylindrical instead of spherical geometry is considered. For radii and temperatures typical of the metal filled core of arcs occurring in gas metal arc welding processes, i.e. radii between 1 and 2 × 10−3 m and temperatures between 5000 and 10 000 K, the scaling of the Stark widths increases the net emission coefficient of iron plasmas by between 2% and 23%. In this parameter range the net emission coefficient of iron plasmas for cylindrical geometry is between 30% and 37% smaller than values calculated for spherical geometry.