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A Hybrid Numerical Methodology Based on CFD and Porous Medium for Thermal Performance Evaluation of Gas to Gas Micro Heat Exchanger

Rehman, Danish; Joseph, Jojomon; Morini, Gian Luca; Delanaye, Michel; Brandner, Juergen

Abstract:
In micro heat exchangers, due to the presence of distributing and collecting manifolds as well as hundreds of parallel microchannels, a complete conjugate heat transfer analysis requires a large amount of computational power. Therefore in this study, a novel methodology is developed to model the microchannels as a porous medium where a compressible gas is used as a working fluid. With the help of such a reduced model, a detailed flow analysis through individual microchannels can be avoided by studying the device as a whole at a considerably less computational cost. A micro heat exchanger with 133 parallel microchannels (average hydraulic diameter of 200 m) in both cocurrent and counterflow configurations is investigated in the current study. Hot and cold streams are separated by a stainless-steel partition foil having a thickness of 100 μm. Microchannels have a rectangular cross section of 200 μm x 200 μm with a wall thickness of 100 μm in between. As a first step, a numerical study for conjugate heat transfer analysis of microchannels only, without distributing and collecting manifolds is performed. Mass flow inside hot and cold fluid domains is increased such that inlet Reynolds number for both domains remains within the laminar regime. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000117460
Veröffentlicht am 28.02.2020
Originalveröffentlichung
DOI: 10.3390/mi11020218
Scopus
Zitationen: 1
Web of Science
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2072-666X
KITopen-ID: 1000117460
HGF-Programm 43.22.01 (POF III, LK 01)
Functionality by Design
Erschienen in Micromachines
Band 11
Heft 2
Seiten 218
Vorab online veröffentlicht am 20.02.2020
Schlagwörter reduced model, LMTD method, conjugate heat transfer (CHT), compressible fluid, maldistribution
Nachgewiesen in Web of Science
Scopus
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