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Granular dynamics of cohesive powders in a rotating drum as revealed by speckle visibility spectroscopy and synchronous measurement of forces due to avalanching

Lookup NU author(s): Dr Vladimir Zivkovic

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


Abstract

We have used speckle visibility spectroscopy (SVS) and synchronized force measurements to compare the granular dynamics of two cohesive lactose powders, with Sauter mean diameters of ~29 μm and ~151 μm, in a rotating drum. A load cell (LC) was used to measure forces on the drum mounting frame and enable monitoring of bulk powder motion; SVS is a dynamic light scattering technique particularly suited for studying dynamics in dense, non-ergodic granular systems. Our results reveal that surface slumping and intermittent collisional dynamics in the bulk of the bed are correlated, especially for the fine more cohesive particles (Geldart group C/A boundary), butnot as much for the less cohesive larger particles (Geldart group A/B boundary). The specific dissipation energy of the particles in the drum is similar for both powders, and increases linearly with increasing drum speed. However, the dependencies of the load cell and SVS signals on rotation speed have opposing trends for these two powders, indicating different dissipation mechanisms for the different Geldart Groups; collisional dissipation is more important for the Geldart C/A powder, while for the Geldart A/B powder avalanche dissipation is dominant.


Publication metadata

Author(s): Yang H, Jiang GL, Saw HY, Davies C, Biggs MJ, Zivkovic V

Publication type: Article

Publication status: Published

Journal: Chemical Engineering Science

Year: 2016

Volume: 146

Pages: 1-9

Print publication date: 02/06/2016

Online publication date: 16/02/2016

Acceptance date: 08/02/2016

Date deposited: 18/02/2016

ISSN (print): 0009-2509

ISSN (electronic): 1873-4405

Publisher: Elsevier

URL: http://dx.doi.org/10.1016/j.ces.2016.02.023

DOI: 10.1016/j.ces.2016.02.023


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