Effect of drum structure on particle mixing behavior based on DEM method--颗粒学报PARTICUOLOGY

Xu, G., Zhang, Y., Yang, X., Chen, G., & Jin, B. (2023). Effect of drum structure on particle mixing behavior based on DEM method. Particuology, 74, 74-91. https://doi.org/10.1016/j.partic.2022.05.008

Effect of drum structure on particle mixing behavior based on DEM method

Ganggang Xu ^a, Yong Zhang ^a^*, Xigang Yang ^{a b}, Guoqing Chen ^b, Baosheng Jin ^a

a Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, China
b State Key Laboratory of Clean and Efficient Coal-fired Power Generation and Pollution Control, China Energy Science and Technology Research Institute Co., Ltd., Nanjing, 210023, China

10.1016/j.partic.2022.05.008

Volume 74, March 2023, Pages 74-91

Received 8 March 2022, Revised 13 May 2022, Accepted 15 May 2022, Available online 26 May 2022, Version of Record 13 June 2022.

E-mail: zyong@seu.edu.cn

Highlights

• Lacy cylinder drum and lacy-lifter cylinder drum are designed and particle behavior is investigated.

• Rheological characteristics in cylinder drum, lacy cylinder drum and lacy-lifter cylinder drum are compared.

• Active layer thickness is decreased and the particle exchange is inhibited by lifters.

• Particle mixing quality is improved by the lacy drum wall and lifters.

Abstract

The optimization of the drum structure is beneficial to improve the particle motion and mixing in rotary drums. In this work, two kinds of drum structures, Lacy cylinder drum (LC) and Lacy-lifters cylinder drum (LLC), are developed on the basic of cylinder drum to enhance the heat transfer area. The particle motion and mixing process are simulated by DEM method. Based on the grid independence and model validation, the contact number between particles and wall, particle velocity profile, thickness of active layer, particle exchange coefficient, particle concentration profile and mixing index are demonstrated. The influences of the drum structure and the operation parameters are further evaluated. The results show that the contact number between particles and wall is improved in LC and LLC compared to cylinder drum. The particle velocity in LC is higher than that in cylinder drum at high rotating speed, and the particle velocity of the particle falling region is significantly improved in LLC. Compared to cylinder drum and LC, the thickness of active layer in LLC is smaller, while the local particle mixing quality is proved to be the best in the active region. In addition, the particle exchange coefficients between static region and active region in the three drums are compared and LLC is found tending to weaken the particle flow. Besides, the fluctuations of particle concentration in the active region, static region, and boundary region are weakened in LLC, and the equilibrium state is reached earlier. In addition, the overall particle mixing performance in cylinder drum, LC and LLC is analyzed. The particle mixing performance in cylinder drum is the worst, while the difference in mixing quality of LC and LLC depends on the operation conditions.

Graphical abstract

Keywords

Rotating drum; Drum structure; Particle velocity profile; Thickness of active layer; Particle mixing

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