Grinding mechanism of wet vertical spiral stirred mill based on DEM-CFD: Role of grinding sphere motion--颗粒学报PARTICUOLOGY

Ji, H., Wang, Z., Qu, T., Song, X., Tang, B., Li, Y., & Ma, L. (2025). Grinding mechanism of wet vertical spiral stirred mill based on DEM-CFD: Role of grinding sphere motion. Particuology, 103, 151-163. https://doi.org/10.1016/j.partic.2025.05.013

Grinding mechanism of wet vertical spiral stirred mill based on DEM-CFD: Role of grinding sphere motion

Haonan Ji^a, Zhaohua Wang^{a b c *}, Tie Qu^b, Xianzhou Song^{b c}, Biliang Tang^{b c}, Yijiang Li ^a, Lifeng Ma^a *

a School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, 030024, China
b CITIC Heavy Industries Co., Ltd., Luoyang, 471039, China
c Luoyang Mining Machinery Engineering Design Institute Co., Ltd., Luoyang, 471039, China

10.1016/j.partic.2025.05.013

Volume 103, August 2025, Pages 151-163

Received 5 March 2025, Revised 23 April 2025, Accepted 14 May 2025, Available online 30 May 2025, Version of Record 5 June 2025.

E-mail: wangzhaohua@tyust.edu.cn; mlf_zgtyust@163.com

Highlights

• A DEM-CFD model of experimental vertical stirred mill is established.

• Grinding sphere motion is analyzed from trajectory, velocity, force and energy.

• Five grinding zones are divided to reflect regional differences in grinding contribution.

• Motion characteristics will help to better understand the grinding mechanism.

Abstract

The grinding sphere is the main ultra-fine grinding medium for the vertical spiral stirred mill, and its motion characteristics have a significant impact on grinding efficiency. A DEM-CFD model of an experimental mill was established, and the accuracy was verified through experiment. The motion characteristics of grinding spheres were systematically analyzed from four aspects: motion trajectory, velocity, force and energy. The results showed that the motion trajectories of the grinding spheres at the cylinder bottom are the shortest, which can be defined as the inert spheres. The trajectory length increases continuously as the height increases in the cylinder, while it increases first and then decreases with the increase of the radial distance. The velocity of grinding spheres near the agitator blade is the highest, while it is lowest at the cylinder wall. By comparing the total, radial, tangential and axial velocities, it was found that its motion mode is mainly tangential motion around the axis, and the axial and radial velocities are very small. The kinetic energy distribution of the grinding spheres is basically the same as the total velocity. The normal collision force of the grinding sphere is 6 times of the tangential collision force, but the tangential collision energy is about 1.4 times of the normal collision energy. Last, five grinding zones were established to characterize the contribution of grinding spheres inside the cylinder to the grinding efficiency. These results will help to understand the grinding mechanism and provide theoretical guidance for the structural design.

Graphical abstract

Keywords

Vertical stirred mill; DEM-CFD; Grinding sphere; Motion characteristics; Grinding efficiency

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