Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore Density
Gradient metal foam is an advanced heat transfer material that decreases resistance to bubble escape and enhances the transfer of boiling heat. In this study, boiling heat transfer and bubble behavior were studied in an experimental set-up with copper foam bilayers configurated either in positive or...
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Isfahan University of Technology
2023-03-01
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| Series: | Journal of Applied Fluid Mechanics |
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| Online Access: | https://www.jafmonline.net/article_2194_d33ccaeaf4ff96126b0a09b17bac2e6d.pdf |
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| author | H. Wang Q. F. Ying E. Lichtfouse C. G. Huang |
| author_facet | H. Wang Q. F. Ying E. Lichtfouse C. G. Huang |
| author_sort | H. Wang |
| collection | DOAJ |
| description | Gradient metal foam is an advanced heat transfer material that decreases resistance to bubble escape and enhances the transfer of boiling heat. In this study, boiling heat transfer and bubble behavior were studied in an experimental set-up with copper foam bilayers configurated either in positive or inverse gradients, utilizing deionized water as working fluid. Positive gradient refers to arranging metal foam layers with high pore density at the bottom, above the heat source, and low pore density on the top. Results show that the heat transfer is higher for gradient metal foam surfaces, of 6.14×105 W/m2, versus a uniform metal foam surface, of 3.94×105 W/m2. For the positive gradient configuration, boiling heat transfer performance first increased with the pore density, then decreased when the pore density was higher than 60 pores per inch (PPI). By contrast, for the inverse gradient, the heat transfer performance was nearly constant with increasing pore density. At the low pore density, the inverse gradient performed better than the positive gradient during the whole boiling process. At high pore density, the positive gradient structure performed better in heat transfer at the early boiling stage. Three main types of bubble escape were observed: For the positive gradient bilayer, the bubbles moved up or down without lateral interference. In contrast, for inverse gradient, the bubbles mostly escape from the sides, which is easy to induce bubble merging. The inverse gradient surface generates larger bubbles, while the positive gradient surface produces a higher frequency of bubble detachment. Accordingly, two liquid replenishment models are proposed: for the positive gradient, external liquid replenishes from the side into the copper foam, while for inverse gradient, the liquid is mainly replenished from the top. |
| first_indexed | 2024-04-10T05:48:16Z |
| format | Article |
| id | doaj.art-1db71587282849fe9c077c85dd8a0a19 |
| institution | Directory Open Access Journal |
| issn | 1735-3572 1735-3645 |
| language | English |
| last_indexed | 2024-04-10T05:48:16Z |
| publishDate | 2023-03-01 |
| publisher | Isfahan University of Technology |
| record_format | Article |
| series | Journal of Applied Fluid Mechanics |
| spelling | doaj.art-1db71587282849fe9c077c85dd8a0a192023-03-05T06:16:39ZengIsfahan University of TechnologyJournal of Applied Fluid Mechanics1735-35721735-36452023-03-0116597398210.47176/jafm.16.05.16242194Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore DensityH. Wang0Q. F. Ying1E. Lichtfouse2C. G. Huang3College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, ChinaCollege of Environmental Science and Engineering, Donghua University, Shanghai, 201620, ChinaAix Marseille Univ, CNRS, IRD, INRAE, CEREGE, Aix-en-Provence,13007, FranceCollege of Environmental Science and Engineering, Donghua University, Shanghai, 201620, ChinaGradient metal foam is an advanced heat transfer material that decreases resistance to bubble escape and enhances the transfer of boiling heat. In this study, boiling heat transfer and bubble behavior were studied in an experimental set-up with copper foam bilayers configurated either in positive or inverse gradients, utilizing deionized water as working fluid. Positive gradient refers to arranging metal foam layers with high pore density at the bottom, above the heat source, and low pore density on the top. Results show that the heat transfer is higher for gradient metal foam surfaces, of 6.14×105 W/m2, versus a uniform metal foam surface, of 3.94×105 W/m2. For the positive gradient configuration, boiling heat transfer performance first increased with the pore density, then decreased when the pore density was higher than 60 pores per inch (PPI). By contrast, for the inverse gradient, the heat transfer performance was nearly constant with increasing pore density. At the low pore density, the inverse gradient performed better than the positive gradient during the whole boiling process. At high pore density, the positive gradient structure performed better in heat transfer at the early boiling stage. Three main types of bubble escape were observed: For the positive gradient bilayer, the bubbles moved up or down without lateral interference. In contrast, for inverse gradient, the bubbles mostly escape from the sides, which is easy to induce bubble merging. The inverse gradient surface generates larger bubbles, while the positive gradient surface produces a higher frequency of bubble detachment. Accordingly, two liquid replenishment models are proposed: for the positive gradient, external liquid replenishes from the side into the copper foam, while for inverse gradient, the liquid is mainly replenished from the top.https://www.jafmonline.net/article_2194_d33ccaeaf4ff96126b0a09b17bac2e6d.pdfgradient copper foamliquid replenishmentbubble behaviorheat transfer enhancementmultiphase flow |
| spellingShingle | H. Wang Q. F. Ying E. Lichtfouse C. G. Huang Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore Density Journal of Applied Fluid Mechanics gradient copper foam liquid replenishment bubble behavior heat transfer enhancement multiphase flow |
| title | Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore Density |
| title_full | Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore Density |
| title_fullStr | Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore Density |
| title_full_unstemmed | Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore Density |
| title_short | Boiling Heat Transfer in Copper Foam Bilayers in Positive and Inverse Gradients of Pore Density |
| title_sort | boiling heat transfer in copper foam bilayers in positive and inverse gradients of pore density |
| topic | gradient copper foam liquid replenishment bubble behavior heat transfer enhancement multiphase flow |
| url | https://www.jafmonline.net/article_2194_d33ccaeaf4ff96126b0a09b17bac2e6d.pdf |
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