Numerical study of short-circuiting flow and particles in a gas cyclone--颗粒学报PARTICUOLOGY

Dong, S., Wang, C., Zhang, Z., Cai, Q., Dong, K., Cheng, T., & Wang, B. (2023). Numerical study of short-circuiting flow and particles in a gas cyclone. Particuology, 72, 81-93. https://doi.org/10.1016/j.partic.2022.02.008

Numerical study of short-circuiting flow and particles in a gas cyclone

Sijie Dong ^a, Chenwen Wang ^b, Zihui Zhang ^a, Qinyu Cai ^a, Kejun Dong ^c, Teng Cheng ^a *, Bo Wang ^a *

a Key Laboratory of Western China’s Environmental Systems of Ministry of Education, Engineering Research Center of Fine Particle Pollution Control Technology and Equipment of Gansu Province, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
b Key Laboratory of Resource Environment and Sustainable Development of Oasis of Gansu Province, College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730000, China
c Center for Infrastructure Engineering, Western Sydney University, Penrith, NSW 2751, Australia

10.1016/j.partic.2022.02.008

Volume 72, January 2023, Pages 81-93

Received 13 January 2022, Revised 20 February 2022, Accepted 23 February 2022, Available online 3 May 2022, Version of Record 3 May 2022.

E-mail: chengt@lzu.edu.cn; wangbo@lzu.edu.cn

Highlights

• Formation mechanism of short-circuiting flow is revealed.

• Short-circuiting flow region has a small mean age and a large coefficient of variation.

• Increase of inlet velocity increases the proportion of short-circuiting flow.

• Small particles are easily short-circuited due to turbulent dispersion.

• Short-circuiting particle proportion greatly affects collection efficiency.

Abstract

Short-circuiting flow is an important secondary flow in gas cyclones, which has a negative impact on the separation performance. To improve the understanding of the short-circuiting flow and guide the optimization of gas cyclones, this paper presents a numerical study of a cyclone using computational fluid dynamics. Based on the steady flow field, three methods were adopted to investigate the formation mechanism and characteristics of the short-circuiting flow and particles. The temporal variation of the tracer species concentration distribution reveals that the formation mechanism of the short-circuiting flow is the squeeze between the airflows entering the annular space of the gas cyclone at different times. The short-circuiting flow region, distinguished through the spatial distribution of the moments of age, is characterized by a small mean age and a large coefficient of variation. The proportion of the short-circuiting particles increases with the increase of the inlet velocity only for small particles. But with the increase of particle size, the proportion of the short-circuiting particles decreases faster at higher inlet velocities, resulting in significant differences in collection efficiency curves.

Graphical abstract

Keywords

Gas cyclone; Short-circuiting flow; Computational fluid dynamics; Species transport; Moment of age; Particle tracking

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