脉冲放电等离子体光谱干扰机制及其修正方法研究  

Study on Spectral Interference Mechanism and Correction Method of Spark-Induced Breakdown Plasma

作　　者：陈伟泽 喻子彧 覃淮青 卢志民[1,2] 姚顺春 CHEN Wei-ze;YU Zi-yu;QIN Huai-qing;LU Zhi-min;YAO Shun-chun(School of Electric Power,South China University of Technology,Guangzhou 510640,China;Guangdong Province Engineering Research Center of High Efficiency and Low Pollution Energy Conversion,Guangzhou 510640,China)

机构地区：[1]华南理工大学电力学院,广东广州510640 [2]广东省能源高效低污染转化与工程技术研究中心,广东广州510640

出　　处：《光谱学与光谱分析》2024年第2期347-353,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(51676073);霍英东教育基金会高等学校青年教师基金项目(171047);广东省自然科学基金杰出青年项目(2021B1515020071);广东省能源高效清洁利用重点实验室项目(2013A061401005)资助。

摘　　要：为解决脉冲放电击穿颗粒流的等离子体光谱(PF-SIBS)中钨电极激发引起的谱线干扰问题,研究了基于等离子体信号探测优化的谱线干扰修正方法。搭建PF-SIBS测量实验系统,以化学纯石墨的颗粒流为研究对象,根据电极间等离子体产生和消亡过程、各特征谱线在等离子体内的分布情况以及各特征谱线信号强度在电极间的变化规律,解析了放电等离子体内各特征元素蒸发、解离和激发的过程,并据此优化光谱探测位置以减弱谱线干扰。研究结果表明:电子在阴极斑点生成,向阳极发射的过程中与电极金属、石墨颗粒流和电极间空气介质发生碰撞电离,产生更多的电子发射,从而形成并维持从阴极向阳极的放电通道。在阴极区域,高能电场产生的焦耳热促使阴极尖端钨金属蒸发溅射,膨胀产生的冲击使得颗粒和空气被排出阴极区域,钨金属的原子及电子占据在阴极区域;在放电通道中部,电子与密集的石墨颗粒流发生碰撞电离;在阳极区域,剩余的放电能量难以蒸发阳极金属,电子主要电离空气介质。可将阴极到阳极的区域划分为阴极金属激发区、中部颗粒激发区和阳极空气激发区。被电离的电极金属、石墨颗粒、空气介质的离子和中性原子占据各自的激发区域,形成等离子体并辐射出对应的特征谱线。从阴极到阳极的特征谱线强度变化呈现了与上述相同的结果,W 247.78 nm谱线强度在阴极区域较强并呈现逐步降低的趋势;C 247.86 nm谱线强度先增后减,在电极间距中心处达到最大;N 744.23 nm谱线强度逐步增强,在阳极尖端处达到最大。以C-W信号强度比作为C-W谱线干扰程度的评价指标,确定了最佳的光谱探测位置为距阳极0.5 mm处。相比于常见的光谱探测位置(电极间距中心),C-W信号强度比从1.200提升至1.348,C 247.86 nm的分峰拟合值与观测值之比从86.02%提升到94.93%,C-W谱线干扰效应�Aiming at the problem of spectral line interference caused by tungsten electrode excitation in the particle flow-spark induced breakdown spectroscopy,a spectral line interference correction method based on plasma signal detection optimization is studied.The PF-SIBS measurement experimental system was set up.The particle flow of pure chemical graphite was taken as the research object.According to the generation and extinction process of plasma between electrodes,the distribution of characteristic spectral lines in the plasma and the variation of signal intensity of characteristic spectral lines between electrodes,the evaporation,dissociation and excitation process of characteristic elements in the plasma are analyzed,and based on this,the optimal spectral detection position is optimized.The research results show that electrons are generated in the cathode spot,and electrons collide with the electrode metal,graphite particle flow and air medium between electrodes during the process of emission to the anode,resulting in more electron emission,thus forming and maintaining the discharge channel from the cathode to the anode.In the cathode region,the Joule heat generated by the high-energy electric field promotes metal evaporation and sputtering at the cathode tip,and the impact of the expansion causes particles and air to be expelled from the cathode region,and the atoms and electrons of the tungsten metal occupy the cathode area.In the middle of the discharge channel,electrons collide with the dense flow of graphite particles and ionize.In the anode region,the remaining discharge energy is difficult to evaporate the anode metal,and the electrons mainly ionize the air medium.Thus,the region from the cathode to the anode is divided into a cathode metal excitation region,a middle particle excitation region and an anode air excitation region.The ions and neutral atoms of the ionized electrodes metal,graphite particles and air medium occupy their respective excitation regions,forming plasma and radiating corresponding cha

关 键 词：脉冲放电等离子体 谱线干扰 颗粒流 等离子体特性 在线监测 

分 类 号：O433.4[机械工程—光学工程]