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Velocity and size measurement of coal particle by
trajectory imaging |
| WU Xue-cheng,WANG Huai,HU Qian,Wu Ying-chun, CHEN Ling-hong,ZHOU Hao,CEN Ke-fa |
| State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 |
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Abstract To develop on-line measurement techniques for coal powder in pipe, a trajectory imaging based method for velocity and size of coal particles was studied. Images of coal particles at different detection angles and exposure times were obtained, which indicates trajectory images are enough clearcompared to those transient images of coal particles who are normally faint due to their strong absorption character, leading to a possibility that both velocity and size of coal particles may be determined from the length and width of the trajectory. To verify this idea, a large number of trajectory images of coal particles coming out from an electro-vibrating feeder were recorded with a certain exposure time. The statistical distributions of particle velocities and sizes were obtained by analyzing the widths and lengths of particle trajectories. It is found that the mean values as well as the distribution shapes agree well with those from commercial PIV and Malvern sizer, which verify the feasibility of the present measurement method and open a possibility to develop a cheap on-line measurement technique for coal powder in pipe.
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Published: 08 September 2011
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基于轨迹图像的煤粉颗粒速度和粒径测量
为了开发管道煤粉参数的实时在线测量技术,研究基于粒子轨迹图像的煤粉速度和粒径的测量方法.实验研究煤粉颗粒的光散射特性,获得煤粉颗粒在激光照射下不同方向和不同曝光时间下的成像特点,表明在较长曝光时间下的煤粉轨迹图像清晰可辨,弥补由于煤粉强吸收特性引起的瞬态图像偏暗和模糊的不足,并提出利用煤粉颗粒轨迹图像同时测量煤粉颗粒速度和粒径的方法.利用计算机图像处理方法对实验拍摄的大量煤粉轨迹图像进行识别和计算,获得煤粉颗粒的速度和粒径分布,并与商用PIV系统和Malvern粒度仪所得结果基本吻合.结果表明,所提出的基于粒子轨迹图像的煤粉颗粒测量方法切实可行,为开发廉价实用的煤粉颗粒在线测量系统打下基础.
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