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Spin Brazil-nut effect and its reverse in a rotating double-walled drum
Decai Huang1, Ming Lu, Surajit Sen
1Department of Applied Physics, Nanjing University of Science and Technology, 210094 Nanjing, China. hdc@njust.edu.cn
The European Physical Journal. E, Soft Matter
|April 23, 2013
Summary
Binary particle mixtures segregate in rotating drums due to percolation and buoyancy. Rotational speed, particle size, and density determine segregation patterns, which reverse at higher speeds.
Area of Science:
- Physics
- Materials Science
- Chemical Engineering
Background:
- Segregation of granular materials is crucial in various industrial processes.
- Understanding particle dynamics in rotating systems is complex due to competing forces.
Purpose of the Study:
- To investigate the segregation of binary particle mixtures in a rotating double-walled drum.
- To identify the dominant forces and parameters controlling segregation patterns.
Main Methods:
- Numerical simulations were employed to model the behavior of binary mixtures.
- Analysis focused on the interplay of self-gravity, centrifugal force, percolation, and buoyancy.
Main Results:
- Segregation is dominated by percolation and buoyancy effects.
- Rotational speed, particle radius, and density dictate the final segregation state.
- At low speeds, smaller/heavier particles move inward, larger/lighter particles outward; this reverses at high speeds.
Conclusions:
- The study elucidates the complex segregation dynamics in rotating drums.
- Phase diagrams confirm the influence of density and radius ratios on segregation.
- Findings are applicable to optimizing industrial mixing and separation processes.
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