Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons

The innovative rotating looped thermosyphons (RLTs) with and without a coil insert were proposed with cooling applications in rotating machinery. The spatial gradients of body forces among the vapor–liquid mixture of the distilled water in a strong centrifugal acceleration field motivated the flow c...

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Autores principales:	Shyy Woei Chang, Min-Fu Hsieh, Pey-Shey Wu, Wei Ling Cai
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	rotating looped thermosyphon passive heat transfer rotating machinery cooling Chemical technology TP1-1185 Chemistry QD1-999
Acceso en línea:	https://doaj.org/article/61e21674ecf44a94b12d2b9d92633b8d
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spelling	oai:doaj.org-article:61e21674ecf44a94b12d2b9d92633b8d2021-11-25T18:50:21ZConvective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons10.3390/pr91119092227-9717https://doaj.org/article/61e21674ecf44a94b12d2b9d92633b8d2021-10-01T00:00:00Zhttps://www.mdpi.com/2227-9717/9/11/1909https://doaj.org/toc/2227-9717The innovative rotating looped thermosyphons (RLTs) with and without a coil insert were proposed with cooling applications in rotating machinery. The spatial gradients of body forces among the vapor–liquid mixture of the distilled water in a strong centrifugal acceleration field motivated the flow circulation in a RLT to facilitate the latent heat transmissions. The effective thermal conductivity (<i>K<sub>eff</sub></i>), the thermal resistance (<i>R<sub>th</sub></i>), the Nusselt numbers in the condenser (<i>Nu</i><sub>con</sub>) and evaporator (<i>Nu</i><sub>eva</sub>), and the Nusselt number of the airflow induced by the rotating bend of the condenser (<i>Nu<sub>ext</sub></i><sub>,con</sub>) of each RLT were measured at various rotating speeds and heat powers with two filling ratios of 0.5 and 0.8. The increase of filling ratio from 0.5 to 0.8 to maintain a thin liquid film along the rotating inner leg of each RLT substantially improved the heat transfer performances. The <i>K<sub>eff</sub></i>, <i>Nu</i><sub>con</sub>, <i>Nu</i><sub>eva</sub>, and <i>Nu<sub>ext</sub></i><sub>,con</sub> were increased with rotating speed, leading to the corresponding reduction of <i>R<sub>th</sub></i>. On the basis of the experimental data, the empirical correlations that were used to calculate <i>R<sub>th</sub></i>, <i>K<sub>eff</sub></i>, <i>Nu</i><sub>con</sub>, <i>Nu</i><sub>eva</sub>, and <i>Nu<sub>ext</sub></i><sub>,con</sub> of the RLTs at the two filling ratios with and without coil were proposed to assist the relevant design applications.Shyy Woei ChangMin-Fu HsiehPey-Shey WuWei Ling CaiMDPI AGarticlerotating looped thermosyphonpassive heat transferrotating machinery coolingChemical technologyTP1-1185ChemistryQD1-999ENProcesses, Vol 9, Iss 1909, p 1909 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	rotating looped thermosyphon passive heat transfer rotating machinery cooling Chemical technology TP1-1185 Chemistry QD1-999
spellingShingle	rotating looped thermosyphon passive heat transfer rotating machinery cooling Chemical technology TP1-1185 Chemistry QD1-999 Shyy Woei Chang Min-Fu Hsieh Pey-Shey Wu Wei Ling Cai Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons
description	The innovative rotating looped thermosyphons (RLTs) with and without a coil insert were proposed with cooling applications in rotating machinery. The spatial gradients of body forces among the vapor–liquid mixture of the distilled water in a strong centrifugal acceleration field motivated the flow circulation in a RLT to facilitate the latent heat transmissions. The effective thermal conductivity (<i>K<sub>eff</sub></i>), the thermal resistance (<i>R<sub>th</sub></i>), the Nusselt numbers in the condenser (<i>Nu</i><sub>con</sub>) and evaporator (<i>Nu</i><sub>eva</sub>), and the Nusselt number of the airflow induced by the rotating bend of the condenser (<i>Nu<sub>ext</sub></i><sub>,con</sub>) of each RLT were measured at various rotating speeds and heat powers with two filling ratios of 0.5 and 0.8. The increase of filling ratio from 0.5 to 0.8 to maintain a thin liquid film along the rotating inner leg of each RLT substantially improved the heat transfer performances. The <i>K<sub>eff</sub></i>, <i>Nu</i><sub>con</sub>, <i>Nu</i><sub>eva</sub>, and <i>Nu<sub>ext</sub></i><sub>,con</sub> were increased with rotating speed, leading to the corresponding reduction of <i>R<sub>th</sub></i>. On the basis of the experimental data, the empirical correlations that were used to calculate <i>R<sub>th</sub></i>, <i>K<sub>eff</sub></i>, <i>Nu</i><sub>con</sub>, <i>Nu</i><sub>eva</sub>, and <i>Nu<sub>ext</sub></i><sub>,con</sub> of the RLTs at the two filling ratios with and without coil were proposed to assist the relevant design applications.
format	article
author	Shyy Woei Chang Min-Fu Hsieh Pey-Shey Wu Wei Ling Cai
author_facet	Shyy Woei Chang Min-Fu Hsieh Pey-Shey Wu Wei Ling Cai
author_sort	Shyy Woei Chang
title	Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons
title_short	Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons
title_full	Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons
title_fullStr	Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons
title_full_unstemmed	Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons
title_sort	convective heat transfer motivated by liquid-to-vapor density difference in centrifugal force field of axially rotating loop thermosyphons
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/61e21674ecf44a94b12d2b9d92633b8d
work_keys_str_mv	AT shyywoeichang convectiveheattransfermotivatedbyliquidtovapordensitydifferenceincentrifugalforcefieldofaxiallyrotatingloopthermosyphons AT minfuhsieh convectiveheattransfermotivatedbyliquidtovapordensitydifferenceincentrifugalforcefieldofaxiallyrotatingloopthermosyphons AT peysheywu convectiveheattransfermotivatedbyliquidtovapordensitydifferenceincentrifugalforcefieldofaxiallyrotatingloopthermosyphons AT weilingcai convectiveheattransfermotivatedbyliquidtovapordensitydifferenceincentrifugalforcefieldofaxiallyrotatingloopthermosyphons
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Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons

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