摘要
在电弧等离子体的光谱诊断中,标准温度法测温原理与目前先进的图像传感技术相结合,通过特征谱图像完成电弧全场温度信息采集,因其良好的时、空分辨率而被广泛应用于电弧温度测量。但是谱线的发射系数与等离子体温度不是单调变化关系,传统标准温度法选取一条ArⅠ谱线完成对电弧等离子体的测量,在电弧内部的高温电离区域产生谱线辐射强度降低的现象,需要人为判定电弧不同位置所处的温度区间才能完成温度的计算,整个过程无法通过软件自主完成。针对此问题,根据电弧等离子体的局部热力学平衡条件,探索一种基于双特征谱线的标准温度法测温原理,通过融合电弧在外层低温区域聚集的Ar原子发出的ArⅠ谱线发射系数场,和在高温区域的Ar一次电离离子所发出的ArⅡ特征谱线发射系数场,将达到ArⅠ谱线标准温度的位置处的ArⅡ谱线发射系数作为电弧不同温度区域的判定依据,完成电弧等离子体高温区域的自动判别,继而应用ArⅠ谱线发射系数与温度对应关系在电弧高、低温区域分别计算电弧温度,消除单一的ArⅠ谱线发射系数场暗区给计算带来的不利影响;设计并搭建了一种镜前分幅采集系统,其中分光镜将弧光等能量分成两束,利用两组反射镜和窄带滤光片建立起两路光学通道,使CMOS在一次曝光中完成两组电弧特征谱图像的采集,并且两幅图像的采集时刻、焦距、光圈等拍摄参数完全一致,达到良好的时间、空间一致性,从而减小谱线融合时误差的输出,满足了原位获取两组电弧特征谱图像的需求;为验证测量系统可行性以及后期的电弧图像提取,以黑白棋盘为标靶,用Harris算子对系统采集的图像进行扫描,根据角点坐标证明系统所采集的两幅图像具有良好的一致性,并且据此将两幅图像做归一化处理,以便后期的电弧特征谱图像的提取;通过假设�
In the research field of arc plasma spectrum diagnosis,combined with the advanced image sensing technology,the Fowler-Milne method uses spectral image to obtain temperature information of arc plasma.Because of its high time and space resolution,the Fowler-Milne method is widely used in arc plasma temperature measurement.However,the relationship between line emission coefficient and temperature is not monotonous,and traditional Fowler-Milne method selects one ArⅠspectral line to complete the measurement,which leads to the decrease of line intensity,and the process of measurement needs researchers to determine the temperature range of different locations to complete the calculation of temperature.The whole process can’t be automatically completed by software.In view of this problem,based on PLTE conditions of arc plasma,applying the partial LTE model of arc plasma,modified Fowler-Milne method based on two spectrum line,which combines the ArⅠspectral line emitted by Ar atoms in an outer low temperature region of arc,and the ArⅡspectral line emitted by Ar ionization ion in hightemperature area of arc,to determine the different temperature range of the arc plasma,and then the whole temperature is calculated by the temperature corresponding to the intensity of the ArⅠspectral line in low-temperature area and high-temperature area,eliminating the adverse effects of single ArⅠspectral line emission coefficient field.A light splitting system was also designed and built,dividing the light of arc into two beams by a spectroscope.Two sets of reflectors and narrow-band filters were used to collect the image of two sets of arc spectral images though one exposure,of which parameters such as the focal length aperture are exactly the same,achieving good time and spatial consistency and reducing the error of emission coefficient fusion.In order to verify the feasibility of measurement system and arc image extraction,black and white chessboard was used as a target,and the extraction of corners extracting of two image pr
作者
蒋凡
李元锋
陈树君
李诚
JIANG Fan;LI Yuan-feng;CHEN Shu-jun;LI Cheng(Engineering Research Center of Advanced Manufacturing Technology for Automotive Components,Ministry of Education,Beijing University of Technology,Beijing 100124,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2019年第2期370-376,共7页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(51875004)
北京市自然科学基金项目(3172004)
先进焊接与连接国家重点实验室开放课题研究基金项目(AWJ-16-M06)资助
