Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface
Heat transfer characteristic of a closed two-phase thermosyphon with enhanced boiling surface is studied and compared with that of a copper mirror surface. Two-phase cooling is widely used in application of thermal engineering and considerably more efficient than single-phase liquid cooling. The eva...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
The Japan Society of Mechanical Engineers
2018-04-01
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| Series: | Journal of Thermal Science and Technology |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/jtst/13/1/13_2018jtst0011/_pdf/-char/en |
| _version_ | 1818313043961970688 |
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| author | Hongbin HE Biao SHEN Liangyu CHEN Sumitomo HIDAKA Koji TAKAHASHI Masamichi KOHNO Yasuyuki TAKATA |
| author_facet | Hongbin HE Biao SHEN Liangyu CHEN Sumitomo HIDAKA Koji TAKAHASHI Masamichi KOHNO Yasuyuki TAKATA |
| author_sort | Hongbin HE |
| collection | DOAJ |
| description | Heat transfer characteristic of a closed two-phase thermosyphon with enhanced boiling surface is studied and compared with that of a copper mirror surface. Two-phase cooling is widely used in application of thermal engineering and considerably more efficient than single-phase liquid cooling. The evaporator surfaces, coated with a pattern of hydrophobic circular spots (0.5 - 2 mm in diameter and 1.5 - 3 mm in pitch) on Cu substrates, achieve very high heat transfer coefficient and low incipience temperature overshoot with water as working fluid. Sub-atmospheric boiling on the hydrophobic spot-coated surface shows a much better heat transfer performance. Tests under heat loads 30 W to 260 W reveal the coated surfaces enhance nucleate boiling performance by increasing the bubbles nucleation-site density. The surface with hydrophobic spots with diameter 1 mm and pitch 1.5 mm achieves the maximal heat transfer enhancement with the minimum boiling thermal resistance as low as 0.03 K/W. A comparison of three evaporator surfaces with identical wettability patterns but with different surface topographies and coating thicknesses is carried out experimentally. The results show superior heat transfer rates and wear resistance on the surface coated with HNTs spots thanks to the large contact angle, great thickness, and durability of the coating layer. |
| first_indexed | 2024-12-13T08:27:29Z |
| format | Article |
| id | doaj.art-1b346496a8504efd9da438c673c6e52d |
| institution | Directory Open Access Journal |
| issn | 1880-5566 |
| language | English |
| last_indexed | 2024-12-13T08:27:29Z |
| publishDate | 2018-04-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Journal of Thermal Science and Technology |
| spelling | doaj.art-1b346496a8504efd9da438c673c6e52d2022-12-21T23:53:51ZengThe Japan Society of Mechanical EngineersJournal of Thermal Science and Technology1880-55662018-04-01131JTST0011JTST001110.1299/jtst.2018jtst0011jtstHeat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surfaceHongbin HE0Biao SHEN1Liangyu CHEN2Sumitomo HIDAKA3Koji TAKAHASHI4Masamichi KOHNO5Yasuyuki TAKATA6Department of Mechanical Engineering, Kyushu UniversityDepartment of Mechanical Engineering, Kyushu UniversitySchool of Mechanical Engineering and Automation, Northeastern UniversityDepartment of Mechanical Engineering, Kyushu UniversityDepartment of Mechanical Engineering, Kyushu UniversityDepartment of Mechanical Engineering, Kyushu UniversityDepartment of Mechanical Engineering, Kyushu UniversityHeat transfer characteristic of a closed two-phase thermosyphon with enhanced boiling surface is studied and compared with that of a copper mirror surface. Two-phase cooling is widely used in application of thermal engineering and considerably more efficient than single-phase liquid cooling. The evaporator surfaces, coated with a pattern of hydrophobic circular spots (0.5 - 2 mm in diameter and 1.5 - 3 mm in pitch) on Cu substrates, achieve very high heat transfer coefficient and low incipience temperature overshoot with water as working fluid. Sub-atmospheric boiling on the hydrophobic spot-coated surface shows a much better heat transfer performance. Tests under heat loads 30 W to 260 W reveal the coated surfaces enhance nucleate boiling performance by increasing the bubbles nucleation-site density. The surface with hydrophobic spots with diameter 1 mm and pitch 1.5 mm achieves the maximal heat transfer enhancement with the minimum boiling thermal resistance as low as 0.03 K/W. A comparison of three evaporator surfaces with identical wettability patterns but with different surface topographies and coating thicknesses is carried out experimentally. The results show superior heat transfer rates and wear resistance on the surface coated with HNTs spots thanks to the large contact angle, great thickness, and durability of the coating layer.https://www.jstage.jst.go.jp/article/jtst/13/1/13_2018jtst0011/_pdf/-char/enthermosyphonwettabilityhydrophobic spotboiling heat transferbubble behaviour |
| spellingShingle | Hongbin HE Biao SHEN Liangyu CHEN Sumitomo HIDAKA Koji TAKAHASHI Masamichi KOHNO Yasuyuki TAKATA Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface Journal of Thermal Science and Technology thermosyphon wettability hydrophobic spot boiling heat transfer bubble behaviour |
| title | Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface |
| title_full | Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface |
| title_fullStr | Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface |
| title_full_unstemmed | Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface |
| title_short | Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface |
| title_sort | heat transfer enhancement of a loop thermosyphon with a hydrophobic spot coated surface |
| topic | thermosyphon wettability hydrophobic spot boiling heat transfer bubble behaviour |
| url | https://www.jstage.jst.go.jp/article/jtst/13/1/13_2018jtst0011/_pdf/-char/en |
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