Rotation speed measurement of moving particles in a CFB riser--颗粒学报PARTICUOLOGY

Wu, X., Wang, Q., Luo, Z., Fang, M., & Cen, K. (2009). Rotation speed measurement of moving particles in a CFB riser. Particuology, 7(4), 238–244. https://doi.org/10.1016/j.partic.2009.02.003

Rotation speed measurement of moving particles in a CFB riser

Xuecheng Wu, Qinhui Wang^*, Zhongyang Luo, Mengxiang Fang, Kefa Cen

State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, Zhejiang 310027, China

10.1016/j.partic.2009.02.003

Volume 7, Issue 4, August 2009, Pages 238-244

Received 22 October 2008, Accepted 22 February 2009, Available online 3 July 2009.

E-mail: qhwang@zju.edu.cn

Highlights

Abstract

This paper presents a study on measuring rotation speed of moving glass beads with an average diameter of 500 μm in a pilot-scale circulating fluidized bed (CFB) riser with a high-speed digital imaging system. Two methods have been developed to calculate particle rotation speed from the particle images. The first method consists of a fully automated algorithm based on cross-correlation of gray distribution of particle images for particles whose rotation axes are (nearly) perpendicular to the imaging plane, and the second method calculates the speed of particle rotation by identifying its rotation axis using two or more characteristic points on its surface. The reliability of the two methods is verified by using a small sphere with known speed and direction of rotation. The first method is shown to be capable of measuring accurately the rotation speed for the particle with a rotation axis (nearly) perpendicular to the imaging plane and filtering off other particles using an appropriate threshold of correlation coefficient. The second method is shown to be capable of yielding both the speed and direction of particle rotation, with a measurement error of less than 10%. Results of both methods on real glass beads in a CFB riser are compared against each other.

Graphical abstract

Keywords

Rotation speed measurement; Moving particles; Gas–solid flow; Circulating fluidized bed (CFB)

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