The effects of exothermic catalytic reactions upon combined transport of heat and mass in porous microreactors

Hunt, G. , Karimi, N. , Yadollahi, B. and Torabi, M. (2019) The effects of exothermic catalytic reactions upon combined transport of heat and mass in porous microreactors. International Journal of Heat and Mass Transfer, 134, pp. 1227-1249. (doi:10.1016/j.ijheatmasstransfer.2019.02.015)

Hunt, G. , Karimi, N. , Yadollahi, B. and Torabi, M. (2019) The effects of exothermic catalytic reactions upon combined transport of heat and mass in porous microreactors. International Journal of Heat and Mass Transfer, 134, pp. 1227-1249. (doi:10.1016/j.ijheatmasstransfer.2019.02.015)

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Abstract

Microreactors for chemical synthesis and combustion have already attracted significant attention. Exothermic catalytic activity features heavily in these devices and thus advective-diffusive transport is of key importance in their analyses. Yet, thermal modelling of the heat generated by catalytic reactions on the internal surfaces of porous microreactors has remained as an important unresolved issue. To address this, the diffusion of heat of catalytic reactions into three phases including fluid, porous solid and solid walls is investigated by extending an existing interface model of porous media under local thermal non-equilibrium. This is applied to a microchannel fully filled with a porous material, subject to a heat flux generated by a catalytic layer coated on the porous-wall boundary. The finite wall thickness and viscous dissipation of the flow kinetic energy are considered, and a two-dimensional analytical model is developed, examining the combined heat and mass transfer and thermodynamic irreversibilities of the system. The analytical solution is validated against the existing theoretical studies on simpler configurations as well as a computational model of the microreactor in the limit of very large porosity. In keeping with the recent findings, the wall thickness is shown to strongly influence the heat and mass transport within the system. This remains unchanged when the symmetricity of the microchannel is broken through placing walls of unequal thicknesses, while deviation from local thermal equilibrium is significantly intensified in this case. Importantly, the Nusselt number is shown to have a singular point, which remains fixed under various conditions.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hunt, Graeme and Yadollahi, Dr Bijan and Karimi, Dr Nader
Authors: Hunt, G., Karimi, N., Yadollahi, B., and Torabi, M.
College/School:College of Science and Engineering > School of Engineering
College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:International Journal of Heat and Mass Transfer
Publisher:Elsevier
ISSN:0017-9310
ISSN (Online):1879-2189
Published Online:23 February 2019
Copyright Holders:Copyright © 2019 Elsevier Ltd.
First Published:First published in International Journal of Heat and Mass Transfer 134: 1227-1249
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
678901EPSRC DTG 2014Mary Beth KneafseyEngineering and Physical Sciences Research Council (EPSRC)EP/M506539/1R&I - RESEARCH STRATEGY & INNOVATION