Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface

Hongbin He, Biao Shen, Liangyu Chen, Sumitomo Hidaka, Koji Takahashi, Masamichi Kohno, Yasuyuki Takata

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish
Article numberJTST0011
JournalJournal of Thermal Science and Technology
Volume13
Issue number1
DOIs
Publication statusPublished - Jan 1 2018

Fingerprint

thermosiphons
Thermosyphons
heat transfer
Heat transfer
augmentation
Boiling liquids
boiling
Evaporators
evaporators
Cooling
Coatings
Nucleate boiling
coatings
nucleate boiling
Surface topography
liquid cooling
Thermal load
working fluids
Heat resistance
thermal resistance

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Instrumentation
  • Engineering (miscellaneous)

Cite this

Heat transfer enhancement of a loop thermosyphon with a hydrophobic spot-coated surface. / He, Hongbin; Shen, Biao; Chen, Liangyu; Hidaka, Sumitomo; Takahashi, Koji; Kohno, Masamichi; Takata, Yasuyuki.

In: Journal of Thermal Science and Technology, Vol. 13, No. 1, JTST0011, 01.01.2018.

Research output: Contribution to journalArticle

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