Elongation of liquid film in wick by utilizing low-voltage horizontal-field electrowetting technique

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03900
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Shibaura Institute of Technology
• Principal Investigator: Ono Naoki 芝浦工業大学, 工学部, 教授 (20407224)
• Co-Investigator(Kenkyū-buntansha): 丹下 学 芝浦工業大学, 工学部, 准教授 (70549584)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ヒートパイプ / エレクトロウエッティング / 濡れ性 / ウイック / 誘電膜

Outline of Final Research Achievements

In this study, horizontal electric field type electrowetting (hereinafter referred to as EW) was developed to be driven by low electric voltage, and the technology to operate in a sealed low-pressure environment inside a heat pipe was investigated with the aim of suppressing the occurrence of dryout in heat pipes used in smartphones, etc. A special experimental heat pipe incorporating EW was used. The behaviour of the temperature and pressure of the water vapour when the EW was applied, showed that dryout was suppressed and delayed under conditions where dryout occurs without the EW. Next, the maximum heat transport immediately before the onset of dryout was investigated, and it was found that the maximum heat transport was increased by about two times when EW was applied. END

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

本研究がもたらす学術的意義は，エレクトロウエッティング（以下EWと呼ぶ）がヒートパイプのドライアウト現象の抑制・遅延に有効であることを実験的に示したことと言える．ヒートパイプとEWの組み合わせはこれまでに無いものである．社会的意義としては，スマートフォン等の小型IT機器内でも適用が可能となるように，水平電界型のEWを工夫した点と，低電圧で駆動するように極薄の誘電膜を用いて液膜伸長効果が現れることを示したことにある．スマートフォン等のIT機器の今後のCPUの高性能化や小型化・薄型化に伴う高発熱化（高熱流束化）に対応する一つの方策としてこの技術を示すことができた．以上