Improvement of lubrication / heat removal characteristics of oil-soaked metal members by applying an electric field and elucidation of the mechanism

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K04596
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 24020:Marine engineering-related
• Research Institution: Fisheries Research and Education Agency
• Principal Investigator: Tamura Satoshi 国立研究開発法人水産研究・教育機構, 水産大学校, 准教授 (20367832)
• Co-Investigator(Kenkyū-buntansha): 佐々木 千鶴 徳島大学, 大学院社会産業理工学研究部(生物資源産業学域), 准教授 (50452652)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 電場付与 / 脂肪酸 / 電気対流 / 熱伝達

Outline of Final Research Achievements

By applying an electric field, the enhancement of the heat transfer ability in a thin oil film between two metallic bodies with different initial temperatures was evaluated. Fatty acids (lauric acid and oleic acid) and a saturated hydrocarbon (squalane) were used as test oils. In the applied experimental condition of the high-temperature body as a positive electrode with an electric field of approximately 1.2 × 10^6 V/m in the gap distance 0.27 mm, the heat transfer of the lauric-acid film improved remarkably, with its value being 3.2 times that in the no-electric-field case. However, such improvement was not observed with squalane, whose molecules comprise a nonpolar group. It was considered that the improvement of heat transfer is realized by electroconvection, which is induced by thermal convection, adsorption, and desorption of the fatty-acid molecules near the surface of the heated metal.

Free Research Field

材料工学，生産技術

Academic Significance and Societal Importance of the Research Achievements

脂肪酸が含まれた油を用いて金属（高温側）- 油膜 - 金属（低温側）となる組合せの伝熱界面を形成し，金属間に直流電圧を印加して伝熱界面部に電場をかけると，電気対流現象により熱の伝達が著しく改善されることが明らかになった。油膜を挟んだ金属間の熱伝達係数は電場の付与によって数倍向上する。この現象は，材料加工，潤滑システム，食品加工などの高度化に寄与するものと考えられる。