结合计算机断层成像算法与吸收光谱气体测量技术,实现了对于均匀温度压力下气体分布二维图像重建。设计搭建了基于4个小型旋转平台摆动扫描的断层重建系统,在0.1 s内完成对于16 cm×16 cm测量区域的空间扫描,获得由激光器高速扫描气体吸收谱线所采集得到的400组投影数据。采用数值模拟方法,利用代数迭代重建算法(ART)与最小二乘QR分解算法进行重建与对比,并考察了气体浓度边界条件对重建结果的影响。实验室内利用体积分数为4 %的NH3混合气体作为测量介质,重建了测量区域内圆形烟道出口不同位置处的气体断层分布图像,并对结果进行了分析。

The absorption spectroscopy combined with computerized tomography technique is used to reconstruct the two-dimensional (2D) image of gas distribution at uniform temperature and pressure. A new optical scanning system is set up based on four rotation platforms. The 16 cm×16 cm region of interest is scanned within 0.1 s,and 400 projections are calculated according to the laser attenuation caused by gas absorption. With numerical simulation,the assumed model of gas distribution is reconstructed by algebraic reconstruction technique (ART) and least square QR-factorization method. The effect of the concentration boundary constants on reconstruction results is also discussed. The experiments are performed on the reconstruction of 4% NH3 distribution at different heights away from the round flue located in the scanning range,and the images are analyzed further.