光谱层析技术诊断等离子体电弧温度场

电子激发温度是等离子体射流物理特性中一个重要参数,温度测量的准确性直接影响其他特性参数。等离子体电弧是等离子体射流的典型代表,研究等离子体电弧的温度场具有重要的指导意义。文章用正交双波长光谱层析技术诊断等离子体电弧温度场的三维分布情况。首先采用正交双波长光学测试系统实时采集等离子体电弧的光谱强度信息,采取改进的最大熵光学层析算法分别重建出2个不同波长对应的发射系数分布状况,然后根据等离子体物理原理,选择谱线相对强度法进行温度场的三维重建,并分析了不同因素对重建结果的影响规律。实验结果表明,该测量系统能实现等离子体电弧温度的三维重建,测量精度较高,能满足实时性要求,为进一步了解和掌握等离子体电弧的内部作用机制奠定了良好的理论和实验基础。

Diagnosis of the Temperature Field of Plasma-arc Using Optical Tomography Technique

The electron excitated temperature is one of the most important parameter of the plasma jet fluidics,and the testing results have great influence on other parameters.The plasma-arc is the representative of the plasma jet fluidics,so it is necessary to research the temperature field of the plasma-arc.In this paper,the authors provide a new technology which is used to diagnose the three-dimension temperature field of the plasma-arc by using orthographic and double-wavelength optical tomography.Firstly,the spectral intensity of the plasma-arc is collected using the CCD,which is placed on the two orthographic direction,then the emission coefficient distribution is reconstructed using the improved max-entropy algorithms;secondly,the spectrum relative intensity method is chosen to calculate the temperature field distribution based on the plasma physical theory;finally,the influence law under different parameter is analyzed.The research results show that this system can realize the three-dimension temperature field reconstruction,the testing precision is high and the result is real time.It provides good theoretical and experimental basis for the further understanding of the inner machanism of the plasma-arc.