Development of a water purification device for space residence using droplets that are self-driven by a surface tension gradient

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K22015
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 24:Aerospace engineering, marine and maritime engineering, and related fields
• Research Institution: Osaka University
• Principal Investigator: Okano Yasunori 大阪大学, 基礎工学研究科, 教授 (90204007)
• Co-Investigator(Kenkyū-buntansha): 稲富 裕光 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 教授 (50249934) ; 堀河 俊英 徳島大学, 大学院社会産業理工学研究部(理工学域), 准教授 (90380112)
• Project Period (FY): 2019-06-28 – 2022-03-31
• Keywords: マランゴニ対流 / 宇宙居住 / 数値解析 / 水浄化

Outline of Final Research Achievements

For the purpose of realizing space residence, we devised a water purification system using self-driven droplets. As the basic research, numerical analysis was used to elucidate the fluid flow when the interfacial tension gradient caused by the concentration difference and the temperature difference coexist. It was found that even if the driving force caused by the concentration difference and the temperature difference is in the same direction or in the opposite direction, the resulting flow cannot be expressed simply by the sum or difference between the them, and exhibits extremely complicated behavior. In addition, the effect of the substrate on the conventional droplet behavior in the liquid was remarkable, and the moving speed was reduced. In addition to this, it was found that the flow phenomenon in the liquid can be controlled by radiative heat transfer control by changing the ambient temperature.

Free Research Field

化学工学

Academic Significance and Societal Importance of the Research Achievements

通常の現象においては温度差と濃度差が共存することが多いが、これまではどちらか一方のみを扱うことがほとんどであった。この両者を同時に考慮することにより新しい現象の発見とそれに伴う新しい制御法の提言が可能となった点に学術的な意義がある。また本法を拡大適用することにより、宇宙環境において従来法に比べ駆動エネルギーが極めて小さい流体輸送システムの構築が可能となり、人類の長年の夢である宇宙居住が実現しうる点に社会的意義がある。