Effect of external factors on segregation of different granular mixtures

Author(s)
D. S. Tan, S. Panda
Publisher
Elsevier
Source
Advanced Powder Technology
Keywords
Chute angle, Discrete element method, Fill height, Granular flow, segregation
Year
2019

Segregation is a common problem faced by different pharmaceutical, chemical, and food processing industries due to non-uniformity in the end-products. Our aim is to minimize the segregation of binary granular mixture by changing the external chute-related factors rather than internal factors like material properties which is often not possible in industries. We investigate the effect of inclination angle, friction, fill volume and channel geometry in a steady, gravity driven flow of granular mixture in an inclined plane. We perform the numerical simulation using an open-source Discrete Element Method code – LIGGGHTS. We observe that the segregation of dry granular particles in stream-wise direction of the chute is minimum at low stream-wise velocity i.e. by keeping the chute at a low inclination and adding the wall roughness. The segregation in cross-stream and vertical direction is at a minimum when the chute is filled to at least 40% of its height. We also investigated the optimal conditions for minimum segregation in different granular mixtures and found that a mixture with size or density ratio up to 4 can have minimum segregation, if we fill the chute to 75% height. For a greater size or density ratio, it is difficult to minimize the segregation. The optimal segregation conditions for mixtures with different elastic modulus ratio were generally constant.

Keywords: Segregation, Chute angle, Fill height, Granular flow, Discrete element method

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