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Study of Transitional Velocities of Solid-Liquid Micro-Circulating Fluidised Beds by Visual Observation

Lookup NU author(s): Emeritus Dr David Reay, Dr Vladimir Zivkovic



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Kagaku Kogaku Kyokai, Society of Chemical Engineers, Japan, 2018.

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Solid-liquid micro-fluidised beds (FBs), i.e. fluidisation of micro-particles in sub-centimetre beds, hold promise of applications in the microfluidics and micro-process technology context. This is mainly due to fluidised particles providing enhancement of mixing, mass and heat transfer under the low Reynolds number flows that dominate in micro-devices. Albeit there are quite a few studies of solid-liquid micro-fluidised beds, we are presenting the first study of a micro-circulating fluidised bed. The present experimental research was performed in a micro-circulating fluidised bed which was made by micro-machining channels of 1mm2 cross section in Perspex. PMMA and soda lime glass micro-particles were used as the fluidised particles and tap water as the fluidising liquid to study flow regime transition for this micro-circulating fluidised bed. The results are in line with macroscopic observation that the critical transition velocity from fluidization to circulating regime is very dependent on solid inventory but once the inventory is high enough it is approximately equal to the particle terminal velocity. However, the transitional velocity is a weakly dependent on wall effect and surface forces confirming the importance of these two properties in a micro-fluidised bed systems. Similarly the transitional velocity to transporting regime is a strong function of surface forces. Finally, combining these results with our previous result on conventional fluidization indicated that map of solid-liquid fluidisation in a micro-circulating fluidised bed system is constructed showing conventional fluidisation, circulating fluidisation and a transport regime.

Publication metadata

Author(s): Nascimento OLD, Reay D, Zivkovic V

Publication type: Article

Publication status: Published

Journal: Journal of Chemical Engineering of Japan

Year: 2018

Volume: 51

Issue: 4

Pages: 349-355

Online publication date: 20/04/2018

Acceptance date: 30/12/2017

Date deposited: 16/01/2018

ISSN (print): 0021-9592

ISSN (electronic): 1881-1299

Publisher: Kagaku Kogaku Kyokai, Society of Chemical Engineers, Japan


DOI: 10.1252/jcej.17we289


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