颗粒相运动参数的光纤式高速摄影测量方法

Measurement method of particle phase motion parameter based on fiber high speed photography

介绍了一种用于测量稠密气固两相流颗粒相运动参数的光纤式高速摄影技术原理及其装置的构建方法.首先,将光纤内窥镜布置在流场内被卤素灯照亮的测量区域,与高速摄像机配合使用,获取颗粒群通过被测区时的运动视频,并对其进行图像预处理,使视频中的每帧图像清晰、无畸变;然后,采用颗粒特征识别算法提取每帧图像上颗粒的瞬时速度,并进行概率分布统计,得到表征颗粒流动特性的速度分布.利用该测量装置对一台截面直径为200 mm、高1 500 mm的三维喷动床进行了实验研究.测量结果表明,颗粒相垂直速度的径向分布曲线可以将颗粒在喷动床轴向截面上的运动特性分为A,B,C三个区域,其中A区与B区的分界点是颗粒相速度为0的点,也是喷动床内喷动区与环隙区的界面位置,这与相关文献的理论预测相吻合.

The measurement method based on the fiber high speed photography and the correspond- ing system are proposed for measuring particle phase motion parameters in a dense phase gas-solid flow. First, a fiber-optic endoscope is inserted into the measurement area of a dense phase gas-solid flow illuminated by halogen. Particles crossing the measurement area are imaged by a high speed in- dustrial camera. Each image of the recorded videos is preprocessed to be clear and without distortion through the noise-removing. Then, particle instantaneous velocities are figured out from a series of images in the video by particle recognition and tracking algorithms. The particle phase velocity dis- tribution characterizing the flow properties is statistically calculated from them. This measurement system is employed in the experimental study of a 3D spouted bed with the diameter of 200 mm and the height of 1 500 mm. The experimental results show that the particle motion characteristics in the axial section of a spouted bed can be classified into three parts of A, B, C according to the radial distribution of particle phase axial velocity. The region boundary between part A and part B is the surface where the particle phase axial velocity trends to zero. It is also the interface between spout and annulus area, which is consistent with the theoretical prediction in other literature.