Wang Xuetao¹，Jiang Yisheng¹，Wang Yulian¹，Liu Yangyang¹，Shao Yuchen¹，Mao Zhiran¹，Cui Baoyu²

1. School of Materials Science and Engineering， Shenyang Ligong University， Shenyang 110159， China；

2. School of Resources and Civil Engineering， Northeastern University， Shenyang 110819， China

Abstract

Objective To optimize the solid-liquid separation efficiency of pulp in the thickener， this study investigates the effects of the volume fraction of solid particles in the initial pulp on the internal flow field characteristics and flocculation performance of the thickener.

Methods A coupled numerical model of computational fluid dynamics-population balance model （CFD-PBM） was established to predict the flow field characteristics and flocculation performance of pulp in the thickener. The internal flow field characteristics of the thickener， including the effective viscosity of pulp， the momentum of pulp， and the turbulent kinetic energy， were analyzed. The effects of the volume fraction of solid particles in the initial pulp on the volume fraction of solid particles in the pulp and the mean floc size distribution at different heights within the feedwell were investigated， and the effects of the volume fraction of solid particles in the initial pulp on the flocculation performance of the thickener were summarized.

Results and Discussion When the volume fraction of solid particles in the initial pulp was 12%， the momentum difference of the pulp between the inlet and outlet of the feedwell reached a maximum of 2 350 kg·m/s， the effective viscosity of the pulp at the outlet of the feedwell was 0.002 2 Pa·s， and the turbulent kinetic energy reached a maximum of 0.015 1 J/kg， indicating that the flow field characteristics of the pulp in the feedwell were optimal. The volume fraction of solid particles in the initial pulp of 12% was conducive to the uniform dispersion and efficient mixing of solid particles and flocculant， increasing the collision frequency between particles， promoting the directional agglomeration of particles， and forming flocs with a certain size and structural stability. The volume fraction of solid particles in the initial pulp was an important parameter affecting the kinetic behavior of particle flocculation and the flow field characteristics of the pulp. By optimizing the volume fraction of solid particles in the initial pulp， the particle velocity and motion trajectory in the pulp could be regulated， thereby improving the flocculation performance of the thickener. When the volume fraction of solid particles in the initial pulp was 12%， the pulp volume fraction distribution within the feedwell was relatively uniform， ranging from approximately 4% to 11%. At a feedwell height of 560 mm， the mean floc size reached a maximum of 152 μm. There was no obvious local enrichment or dilute phase region of flocs， and the flocculation effect was the best.

Conclusion The CFD-PBM coupled numerical model can be adopted to predict the flow field characteristics and flocculation performance of pulp in the thickener. Optimizing the volume fraction of solid particles in the initial pulp can effectively regulate the flow field characteristics of pulp and improve the flocculation performance， thereby achieving efficient operation of the thickener.

Keywords： coupled numerical model； thickener； flow field characteristics； flocculation performance

Get Citation：Wang Xuetao， Jiang Yisheng， Wang Yulian， et al. Optimization of internal flow field characteristics and flocculation performance of thickener based on coupled numerical model［J］. China Powder Science and Technology， 2026， 32（4）： 1-12.

Received：2025-09-21， Revised： 2026-04-02，Online： 2026-06-08.

Funding：The research was supported by the National Natural Science Foundation of China (Grant No. 52374271, 51974066),the Basic Scientific Research Project of the Liaoning Provincial Department of Education (Grant No. LJ212410144059), the High-Level Talent Introduction Program of Shenyang Ligong University (Grant No. 1010147001204), and the Liaoning Provincial Doctoral Scientific Research Startup Fund Program (Grant No. 2025-BS-0357).

DOI：10.13732/j.issn.1008-5548.2026.04.004

CLC No.：TD962.2； TB4

Type Code：A

Serial No.：1008-5548（2026）04-0001-12