Numerical and experimental study on effect of ratio of overflow pipe outer diameter to cylindrical section diameter on hydrocyclone performance--颗粒学报PARTICUOLOGY

a Jiangxi Provincial Key Laboratory of Particle Technology, Jiangxi University of Science and Technology, Nanchang, 330013, China
b Research Centre for Intelligent Mineral Processing & Metallurgy, International Institute for Innovation, Jiangxi University of Science and Technology, Nanchang, 330013, China
c ARC Research Hub for Smart Process Design and Control, Department of Chemical and Biological Engineering, Monash University, VIC, 3800, Australia
d School of Materials Science and Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
e JITRI Institute for Process Modelling and Optimization, Suzhou, 215123, China

10.1016/j.partic.2026.03.021

Volume 113, June 2026, Pages 189-198

Received 23 October 2025, Revised 7 February 2026, Accepted 12 March 2026, Available online 27 March 2026, Version of Record 3 April 2026.

E-mail: dianyu.e@jxust.edu.cn; zhangyuhao@88.com

Highlights

• Effect of overflow pipe-to-cylinder ratio on hydrocyclone performance is explored.

• Internal geometric proportions are crucial for flow field stability, not scale.

• For FX25, an RODCD of 0.72 improves separation efficiency and reduces pressure drop.

• Excessive RODCD in FX25 destabilizes the flow and leads to performance failure.

• Optimal RODCD ranges vary by hydrocyclone size: 0.48–0.64 for FX75, ∼0.72 for FX25.

Abstract

Hydrocyclones are widely used in industrial separation processes due to their compact design and high processing capacity. The structure of the overflow pipe plays a crucial role in determining separation performance. Although numerous studies have explored the effects of overflow pipe wall thickness on hydrocyclone performance, results remain inconsistent. This study combines numerical simulations and physical experiments to investigate the impact of the ratio of the overflow pipe’s outer diameter to the cylinder section diameter (RODCD) on the performance and flow characteristics of hydrocyclones (FX75, FX25, and FX75r). The FX75 is a commonly used medium-scale model, while the FX25 is designed for finer particle separation. The FX75r, geometrically similar to the FX75 but scaled to the size of the FX25, is introduced to examine the effects of RODCD across different geometric designs. The results indicate that for the FX75, optimal separation occurs within an RODCD range of 0.48–0.64, while for the FX25, an RODCD of 0.72 improves performance by reducing pressure drop and enhancing separation efficiency. Increasing the RODCD to 0.72 stabilizes the air core, reduces turbulence, and optimizes the vortex structure, leading to improved separation efficiency and reduced energy consumption. However, at excessive RODCD values (e.g., 0.88), flow field destabilization occurs, impairing effective separation. Geometric similarity validation confirms that hydrodynamic stability at higher RODCD values is more strongly influenced by internal geometric proportions than by cylinder diameter. These findings offer valuable insights into optimizing hydrocyclone design and RODCD to enhance separation efficiency in industrial applications.

Graphical abstract

Keywords

Hydrocyclone; CFD; Overflow pipe-to-cylinder ratio; Flow field characteristics; Separation performance

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