扩散电弧等离子体的“收缩-扩张”及其波动问题的研究

Arc plasma has the characteristicis of smaller area, concentrated energy and inhomogeneous parameters., which That has restricted its application in the large-scale material preparation and production. In the applicant's previous study, the diffuse arc plasma, which has the advantage of large cross-section, uniform temperature, high stability and long laminar plasma, is obtained. Some preliminary research suggests that the diffuse arc plasma shows a very promising applicable future. In the diffuse arc plasma, arc voltage fluctuations which accompany with the brightness (temperature) fluctuations are found. It is inferred there exists some distinct energy coupling mechanisms, which are possibly related to the "contraction/ expansion" fluctuation of arc plasma. This project plans to make further study of the fluctuation characteristics in the diffuse arc plasma by a series of studies. Combining the theories, simulation with experiments, the energy coupling mechanisms between various physical variable and the physical mechanism which causes the arc's "contraction/ expansion" would be analyzed. The effects of external parameters on the fluctuation characteristics would be investigated, so that the fluctuation can be effectively eliminated or restrained. The project study will promote the application of diffuse arc plasma torchesgenerator, deepen our understanding of the arc's "contraction/ expansion" mechanism and enrich the scientific and technological foundation of arc plasma.

电弧等离子体具有体积小、能量高度集中、参数梯度大的特点，难以用于材料制备等行业的规模工业生产。申请人前期研究“扩散电弧等离子体”具有截面积大、温度均匀、稳定性好的特点，且可产生层流射流，具有良好的应用前景。在扩散电弧等离子体发生器中，存在着电弧的电压波动、伴随着扩散电弧等离子体的亮度（温度）波动现象，可能存在着有异于现有研究中的波动的能量耦合机制，其中可能与电弧的“收缩-扩张”波动相关。本项目拟通过系统的实验进一步表征扩散电弧等离子体各波动物理量的特征，结合理论分析和数值模拟，分析“波动”的各物理量之间耦合作用机制，分析引发电弧“收缩/扩张”的物理机制，研究外部条件对电弧“收缩-扩张”及其波动特性的影响，避免或抑制“波动”的产生。项目的研究对于促进扩散电弧等离子体发生器的应用、理解等离子体“收缩/扩张”机制、充实扩散电弧等离子体的科学技术基础、丰富电弧等离子体的科学技术内容具有重要意义。

在电弧等离子体发生器中存在着电弧的“收缩-扩张”波动现象以及可能的波动能量耦合机制，而电弧等离子体波动引起的等离子体参数变化必然会对材料制备及加工的一致性、均匀性产生影响，严重影响产品质量。研究电弧等离子体收缩-扩张及波动特性，探索收缩-扩张波动的产生机制及方法，是兼具重要的学术价值和广泛的应用背景。本项目发展了电弧“收缩-扩张”波动实验装置及测量诊断平台，实现包括放电电压、发生器压力、等离子体参数和位形结构的测量诊断；开展电弧“收缩-扩张”波动理论分析、实验及数值模拟，分析引发电弧“收缩-扩张”的物理机制及影响因素；分析各物理量相互之间的耦合作用关系及对波动特性的影响，理解电弧产生“收缩-扩张”波动的多变量、非线性耦合机制；初步探索了扩散电弧等离子体在高马赫数MHD风洞加速的应用可行性。项目的研究成果对于促进电弧等离子体发生器的应用、理解等离子体“收缩-扩张”机制、充实电弧等离子体的科学技术基础、丰富电弧等离子体的科学技术内容具有重要意义。