Comparative Analysis of Conical and Square Stage Arrangements in Two-Stage Cyclones for Fine-Particle Separation

MSU Affiliation

James Worth Bagley College of Engineering; Michael W. Hall School of Mechanical Engineering

Creation Date

2026-09-30

Abstract

Fine-particle separation remains challenging because micron-sized particles have low inertia and are strongly affected by vortex instability, short-circuit flow, and turbulent dispersion. This numerical study compares a conventional conical cyclone with four two-stage configurations: conical–conical (CC), conical–square (CS), square–square (SS), and square–conical (SC). Gas flow and trajectories of 1–6 μm particles were simulated using the Reynolds Stress Model coupled with the Discrete Phase Model. Validation against experimental data showed that the RSM captured the anisotropic swirling flow more accurately than the SST ��–�� model. Flow structures were analyzed at 12.69 m/s, while pressure drop and collection efficiency were evaluated at 12.69 and 19.1 m/s. Type CC preserved the strongest vortex through both stages and achieved 75% and 82% efficiencies for 1 μm, compared with 7% and 16% for the single-stage cyclone. This improvement increased pressure drop by approximately 20%, from 1342 to 1610 Pa and from 3041 to 3660 Pa. Type CS provided the best efficiency–pressure balance, with performance index (PI) values of 0.1290 and 0.1457. It achieved 1 μm efficiencies of about 53% and 60% with pressure drops of 640 and 1341 Pa. Type SS had the lowest pressure loss but poor fine-particle collection. In Type SC, downstream vortex recovery could not offset weak upstream separation. The single-stage cut-off diameter decreased from about 1.68 to 1.29 μm with increasing velocity. Cut-off diameters were below 1 μm for Types CC, CS, and SC, but above 6 μm for Type SS. These results demonstrate that stage order governs the separation–energy trade-off and that strong upstream classification is more effective than downstream vortex recovery.

Keywords

cyclone separator, multistage cyclone, fine-particle separation, collection efficiency, pressure drop

Publication Date

8-7-2026

Publication Title

Separation and Purification Technology

Publisher

Elsevier

Rights

© 2026 The Authors

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Digital Object Identifier (DOI)

https://doi.org/10.1016/j.seppur.2026.139613