Cargando…
Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution
Miniaturized heat exchangers are well known for their superior heat transfer capabilities in comparison to macro-scale devices. While in standard microchannel systems the improved performance is provided by miniaturized distances and very small hydraulic diameters, another approach can also be follo...
Autores principales: | , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7142721/ https://www.ncbi.nlm.nih.gov/pubmed/32244961 http://dx.doi.org/10.3390/mi11030323 |
_version_ | 1783519447994073088 |
---|---|
author | Joseph, Jojomon Rehman, Danish Delanaye, Michel Morini, Gian Luca Nacereddine, Rabia Korvink, Jan G. Brandner, Juergen J. |
author_facet | Joseph, Jojomon Rehman, Danish Delanaye, Michel Morini, Gian Luca Nacereddine, Rabia Korvink, Jan G. Brandner, Juergen J. |
author_sort | Joseph, Jojomon |
collection | PubMed |
description | Miniaturized heat exchangers are well known for their superior heat transfer capabilities in comparison to macro-scale devices. While in standard microchannel systems the improved performance is provided by miniaturized distances and very small hydraulic diameters, another approach can also be followed, namely, the generation of local turbulences. Localized turbulence enhances the heat exchanger performance in any channel or tube, but also includes an increased pressure loss. Shifting the critical Reynolds number to a lower value by introducing perturbators controls pressure losses and improves thermal efficiency to a considerable extent. The objective of this paper is to investigate in detail collector performance based on reduced-order modelling and validate the numerical model based on experimental observations of flow maldistribution and pressure losses. Two different types of perturbators, Wire-net and S-shape, were analyzed. For the former, a metallic wire mesh was inserted in the flow passages (hot and cold gas flow) to ensure stiffness and enhance microchannel efficiency. The wire-net perturbators were replaced using an S-shaped perturbator model for a comparative study in the second case mentioned above. An optimum mass flow rate could be found when the thermal efficiency reaches a maximum. Investigation of collectors with different microchannel configurations (s-shaped, wire-net and plane channels) showed that mass flow rate deviation decreases with an increase in microchannel resistance. The recirculation zones in the cylindrical collectors also changed the maldistribution pattern. From experiments, it could be observed that microchannels with S-shaped perturbators shifted the onset of turbulent transition to lower Reynolds number values. Experimental studies on pressure losses showed that the pressure losses obtained from numerical studies were in good agreement with the experiments (<4%). |
format | Online Article Text |
id | pubmed-7142721 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-71427212020-04-15 Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution Joseph, Jojomon Rehman, Danish Delanaye, Michel Morini, Gian Luca Nacereddine, Rabia Korvink, Jan G. Brandner, Juergen J. Micromachines (Basel) Article Miniaturized heat exchangers are well known for their superior heat transfer capabilities in comparison to macro-scale devices. While in standard microchannel systems the improved performance is provided by miniaturized distances and very small hydraulic diameters, another approach can also be followed, namely, the generation of local turbulences. Localized turbulence enhances the heat exchanger performance in any channel or tube, but also includes an increased pressure loss. Shifting the critical Reynolds number to a lower value by introducing perturbators controls pressure losses and improves thermal efficiency to a considerable extent. The objective of this paper is to investigate in detail collector performance based on reduced-order modelling and validate the numerical model based on experimental observations of flow maldistribution and pressure losses. Two different types of perturbators, Wire-net and S-shape, were analyzed. For the former, a metallic wire mesh was inserted in the flow passages (hot and cold gas flow) to ensure stiffness and enhance microchannel efficiency. The wire-net perturbators were replaced using an S-shaped perturbator model for a comparative study in the second case mentioned above. An optimum mass flow rate could be found when the thermal efficiency reaches a maximum. Investigation of collectors with different microchannel configurations (s-shaped, wire-net and plane channels) showed that mass flow rate deviation decreases with an increase in microchannel resistance. The recirculation zones in the cylindrical collectors also changed the maldistribution pattern. From experiments, it could be observed that microchannels with S-shaped perturbators shifted the onset of turbulent transition to lower Reynolds number values. Experimental studies on pressure losses showed that the pressure losses obtained from numerical studies were in good agreement with the experiments (<4%). MDPI 2020-03-20 /pmc/articles/PMC7142721/ /pubmed/32244961 http://dx.doi.org/10.3390/mi11030323 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Joseph, Jojomon Rehman, Danish Delanaye, Michel Morini, Gian Luca Nacereddine, Rabia Korvink, Jan G. Brandner, Juergen J. Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution |
title | Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution |
title_full | Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution |
title_fullStr | Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution |
title_full_unstemmed | Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution |
title_short | Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution |
title_sort | numerical and experimental study of microchannel performance on flow maldistribution |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7142721/ https://www.ncbi.nlm.nih.gov/pubmed/32244961 http://dx.doi.org/10.3390/mi11030323 |
work_keys_str_mv | AT josephjojomon numericalandexperimentalstudyofmicrochannelperformanceonflowmaldistribution AT rehmandanish numericalandexperimentalstudyofmicrochannelperformanceonflowmaldistribution AT delanayemichel numericalandexperimentalstudyofmicrochannelperformanceonflowmaldistribution AT morinigianluca numericalandexperimentalstudyofmicrochannelperformanceonflowmaldistribution AT nacereddinerabia numericalandexperimentalstudyofmicrochannelperformanceonflowmaldistribution AT korvinkjang numericalandexperimentalstudyofmicrochannelperformanceonflowmaldistribution AT brandnerjuergenj numericalandexperimentalstudyofmicrochannelperformanceonflowmaldistribution |