Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces

Additive manufacturing (AM) of metal components has opened new frontiers in heat transfer applications owing to its wide design freedom, which enables previously unexplored geometries with enhanced thermal performance to be developed. Open minichannels, on the other hand, consist of an extra manifol...

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Main Authors: Ye, Hanyang, Lum, Leymus Yong Xiang, Kandasamy, Ranjith, Zhao, Huanyu, Ho, Jin Yao
Other Authors: School of Mechanical and Aerospace Engineering
Format: Article
Language:English
Published: 2024
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Online Access:https://hdl.handle.net/10356/180740
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1807402024-10-22T06:34:02Z Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces Ye, Hanyang Lum, Leymus Yong Xiang Kandasamy, Ranjith Zhao, Huanyu Ho, Jin Yao School of Mechanical and Aerospace Engineering Singapore Centre for 3D Printing Engineering Flow boiling Additive manufacturing Additive manufacturing (AM) of metal components has opened new frontiers in heat transfer applications owing to its wide design freedom, which enables previously unexplored geometries with enhanced thermal performance to be developed. Open minichannels, on the other hand, consist of an extra manifold situated above the common flow channels, have been demonstrated to effectively reduce pressure drop and two-phase flow instability by mitigating backflow and maldistribution. In this paper, we synergized open minichannel design methodology with an ultrascalable surface microstructuring method for AM AlSi10Mg to improve flow boiling heat transfer performance of R134a. Experiments were conducted at the refrigerant mass flow rates (ṁ) of 0.005 kg/s to 0.01 kg/s (corresponding to mass fluxes of 73 to 146 kg/m2⋅s), and effective heat fluxes (qeff) of 1.8 kW/m2 to 141 kW/m2, by supplying 2 ℃ subcooled liquid to the minichannel inlet at saturation pressure (Psat) of 7.27 bar. The effects of heat flux, nucleation site density, mass flow rate and location of nucleation sites on the harmonic-average heat transfer coefficient (have) and pressure drop (ΔP) along the flow direction are investigated and compared against a conventionally manufactured (Al6061) counterpart. Our results show that the proposed etching process significantly improves the cooling performance of AM microstrucured minichannels, resulting in 210% higher have than Al6061 with negligible pressure drop penalty. The flow visualization results reveal a sequential order of nucleation site activation with increasing heat flux for microstructured open minichannels, which starts from the top of fins, followed by the corners and other three surfaces within the channels. This also results in the non-negligible effects of mass flow rate on cooling performance for microstructured minichannels, with approximately 10%–66% higher have at the lowest mass flow rate. Besides, the pressure drop penalty resulting from plain AM rough surface is also reduced by up to 13% through the proposed microstructuring process. In all, this work not only successfully identifies the dominant mechanisms in AM microstructured open minichannels, but it also provides useful minichannel design guidelines for high-performance two-phase cooling devices by AM. Ministry of Education (MOE) Nanyang Technological University J.Y. Ho would like to acknowledge the financial support for this project under Nanyang Technological University’s Start-up Grant (SUG) and RS14/21 MOE Tier 1 Grant provided by Ministry of Education (MOE) Singapore. 2024-10-22T06:34:01Z 2024-10-22T06:34:01Z 2024 Journal Article Ye, H., Lum, L. Y. X., Kandasamy, R., Zhao, H. & Ho, J. Y. (2024). Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces. Applied Thermal Engineering, 256, 124150-. https://dx.doi.org/10.1016/j.applthermaleng.2024.124150 1359-4311 https://hdl.handle.net/10356/180740 10.1016/j.applthermaleng.2024.124150 2-s2.0-85201309854 256 124150 en RS14/21 NTU SUG Applied Thermal Engineering © 2024 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering
Flow boiling
Additive manufacturing
spellingShingle Engineering
Flow boiling
Additive manufacturing
Ye, Hanyang
Lum, Leymus Yong Xiang
Kandasamy, Ranjith
Zhao, Huanyu
Ho, Jin Yao
Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces
description Additive manufacturing (AM) of metal components has opened new frontiers in heat transfer applications owing to its wide design freedom, which enables previously unexplored geometries with enhanced thermal performance to be developed. Open minichannels, on the other hand, consist of an extra manifold situated above the common flow channels, have been demonstrated to effectively reduce pressure drop and two-phase flow instability by mitigating backflow and maldistribution. In this paper, we synergized open minichannel design methodology with an ultrascalable surface microstructuring method for AM AlSi10Mg to improve flow boiling heat transfer performance of R134a. Experiments were conducted at the refrigerant mass flow rates (ṁ) of 0.005 kg/s to 0.01 kg/s (corresponding to mass fluxes of 73 to 146 kg/m2⋅s), and effective heat fluxes (qeff) of 1.8 kW/m2 to 141 kW/m2, by supplying 2 ℃ subcooled liquid to the minichannel inlet at saturation pressure (Psat) of 7.27 bar. The effects of heat flux, nucleation site density, mass flow rate and location of nucleation sites on the harmonic-average heat transfer coefficient (have) and pressure drop (ΔP) along the flow direction are investigated and compared against a conventionally manufactured (Al6061) counterpart. Our results show that the proposed etching process significantly improves the cooling performance of AM microstrucured minichannels, resulting in 210% higher have than Al6061 with negligible pressure drop penalty. The flow visualization results reveal a sequential order of nucleation site activation with increasing heat flux for microstructured open minichannels, which starts from the top of fins, followed by the corners and other three surfaces within the channels. This also results in the non-negligible effects of mass flow rate on cooling performance for microstructured minichannels, with approximately 10%–66% higher have at the lowest mass flow rate. Besides, the pressure drop penalty resulting from plain AM rough surface is also reduced by up to 13% through the proposed microstructuring process. In all, this work not only successfully identifies the dominant mechanisms in AM microstructured open minichannels, but it also provides useful minichannel design guidelines for high-performance two-phase cooling devices by AM.
author2 School of Mechanical and Aerospace Engineering
author_facet School of Mechanical and Aerospace Engineering
Ye, Hanyang
Lum, Leymus Yong Xiang
Kandasamy, Ranjith
Zhao, Huanyu
Ho, Jin Yao
format Article
author Ye, Hanyang
Lum, Leymus Yong Xiang
Kandasamy, Ranjith
Zhao, Huanyu
Ho, Jin Yao
author_sort Ye, Hanyang
title Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces
title_short Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces
title_full Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces
title_fullStr Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces
title_full_unstemmed Flow boiling heat transfer enhancement of R134a in additively manufactured minichannels with microengineered surfaces
title_sort flow boiling heat transfer enhancement of r134a in additively manufactured minichannels with microengineered surfaces
publishDate 2024
url https://hdl.handle.net/10356/180740
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