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Thermofluid Physics of Drops for Digital Microfluidics

Research Project

Project/Area Number 19K23491
Research Category

Grant-in-Aid for Research Activity Start-up

Allocation TypeMulti-year Fund
Review Section 0301:Mechanics of materials, production engineering, design engineering, fluid engineering, thermal engineering, mechanical dynamics, robotics, aerospace engineering, marine and maritime engineering, and related fields
Research InstitutionKyushu University

Principal Investigator

Kita Yutaku  九州大学, 工学研究院, 助教 (40840616)

Project Period (FY) 2019-08-30 – 2021-03-31
Project Status Completed (Fiscal Year 2020)
Budget Amount *help
¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords液滴 / マランゴニ対流 / 流れ可視化 / 蒸発 / 赤外線サーモグラフィ / 接触角 / マイクロ流体
Outline of Research at the Start

デジタル流体デバイス技術に向けて,マイクロヒータを用いた局所加熱による液滴内部対流の制御に必要な熱流動現象の学術的基盤を築くことを目指す.赤外線サーモグラフィおよび粒子画像流速測定により,温度場・速度場情報を同時取得することで,与えられた加熱量・温度が液滴内部対流の流速や温度上昇に及ぼす影響を明らかにする.また,液滴形状(接触角や体積)が熱対流の安定性に及ぼす影響を調査する.最終的には加熱条件・液滴形状等のパラメータから計算される無次元数(レイリー数やマランゴニ数)で,対流強度や熱伝達特性を整理し,熱流動特性の支配パラメータを特定する.

Outline of Final Research Achievements

The present project investigates the effect of drop geometry i.e. volume and contact angle on the stability of internal flows of pure water drop which is heated locally. A laser is used to heat the substrate, providing an artificial thermal gradient over the drop which drives surface-tension driven Marangoni convection. Using several coating materials, the contact angle is tuned in a range between 70 and 150 degrees. The thermal activities and corresponding flows are monitored with infrared thermography.

Academic Significance and Societal Importance of the Research Achievements

医療分析や創薬研究への応用が期待される次世代マイクロ流体デバイスにおいて,液滴をマイクロリアクタとして利用しようという流れがある.その中で液滴は試料混合・反応・検出という機能を果たすが,そのために液滴内部の熱流動現象を理解し,制御するための技術を確立させる必要がある.本研究は,局所加熱による液滴内部対流の発生および制御を行うという,アクティブ液滴制御の先駆け的な取り組みである.本研究ではレーザを用いて液滴を加熱したが,実用面ではマイクロ流体チップに搭載が容易なマイクロヒータでも同様の効果が得られる.まだ液滴のアクティブ制御はまだ黎明期であるため,本研究がこの分野にもたらす貢献度は非常に大きい.

Report

(3 results)
  • 2020 Annual Research Report   Final Research Report ( PDF )
  • 2019 Research-status Report
  • Research Products

    (14 results)

All 2021 2020 2019 Other

All Int'l Joint Research (2 results) Journal Article (2 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 2 results,  Open Access: 1 results) Presentation (10 results) (of which Int'l Joint Research: 5 results,  Invited: 4 results)

  • [Int'l Joint Research] エディンバラ大学/イーストアングリア大学(英国)

    • Related Report
      2020 Annual Research Report
  • [Int'l Joint Research] University of Edinburgh/University of East Anglia(英国)

    • Related Report
      2019 Research-status Report
  • [Journal Article] On the onset of quench during spray cooling: The significance of oxide layers2020

    • Author(s)
      Tsukamoto Kengo、Kita Yutaku、Inoue Shinya、Hamanosono Takafumi、Hidaka Sumitomo、Ueoka Satoshi、Fukuda Hiroyuki、Kohno Masamichi、Takata Yasuyuki
    • Journal Title

      Applied Thermal Engineering

      Volume: 179 Pages: 115682-115682

    • DOI

      10.1016/j.applthermaleng.2020.115682

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Drop Evaporation on Rough Hot-Spots: Effect of Wetting Modes2019

    • Author(s)
      Zhang Huacheng、Kita Yutaku、Zhang Dejian、Nagayama Gyoko、Takata Yasuyuki、Sefiane Khellil、Askounis Alexandros
    • Journal Title

      Heat Transfer Engineering

      Volume: 41 Issue: 19-20 Pages: 1-9

    • DOI

      10.1080/01457632.2019.1640458

    • Related Report
      2019 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Presentation] Quench mechanisms of spray cooling - from single droplet to spray level2021

    • Author(s)
      Yutaku Kita
    • Organizer
      Thermal Transport Cafe
    • Related Report
      2020 Annual Research Report
    • Invited
  • [Presentation] 微小液滴の蒸発と不安定熱流動現象について2020

    • Author(s)
      喜多由拓
    • Organizer
      第6回相変化界面研究会
    • Related Report
      2020 Annual Research Report
    • Invited
  • [Presentation] When does hot steel get quenched by sprayed water? - The influence of oxide layers on the onset of quenching2020

    • Author(s)
      Yutaku Kita
    • Organizer
      Sino-Japan-UK Frontiers in Phase Change Heat Transfer and Its Applications in Energy
    • Related Report
      2020 Annual Research Report
    • Invited
  • [Presentation] 赤外線サーモグラフィによる微小液滴の気液相変化と熱流動現象へのアプローチ2020

    • Author(s)
      喜多由拓
    • Organizer
      第48回可視化情報シンポジウム
    • Related Report
      2020 Annual Research Report
    • Invited
  • [Presentation] Water drops evaporating on hot-spots: Influence of contact angle on Marangoni instabilities2019

    • Author(s)
      Yutaku Kita, Huacheng Zhang, Alexandros Askounis, Yasuyuki Takata, Khellil Sefiane
    • Organizer
      The Second Pacific Rim Thermal Engineering Conference (PRTEC2019)
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Thermocapillary-driven flows in pure water drops on a local hot-spot2019

    • Author(s)
      Yutaku Kita, Huacheng Zhang, Alexandros Askounis, Yasuyuki Takata, Khellil Sefiane
    • Organizer
      Droplets 2019
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Water drops walking on superhydrophobic texture patterns2019

    • Author(s)
      Yutaku Kita
    • Organizer
      The Droplets 2019 Satellite Meeting: Droplet and Flow Interactions with Bio-inspired and Smart Surfaces
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Internal flows in pure water drops on a local hot-spot: Onset and growth of thermocapillary instabilities2019

    • Author(s)
      Yutaku Kita, Huacheng Zhang, Alexandros Askounis, Yasuyuki Takata, Khellil Sefian
    • Organizer
      IUTAM Symposium on Computational Modelling of Instabilities and Turbulence in Separated Two-Phase Flows (IUTAM2019)
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] How water drops walk on superhydrophobic surfaces with wettability contrasts2019

    • Author(s)
      Yutaku Kita, Coinneach Mackenzie Dover, Alexandros Askounis, Yasuyuki Takata, Khellil Sefiane
    • Organizer
      Surface Wettability on Phase Change Phenomena (SWEP) Workshop
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] 局所加熱面上の液滴蒸発および熱流動に関する研究2019

    • Author(s)
      喜多 由拓, 張 華誠, Askounis Alexandros, 迫田 直也, 高田 保之, Sefiane Khellil
    • Organizer
      第56回日本伝熱シンポジウム
    • Related Report
      2019 Research-status Report

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Published: 2019-09-03   Modified: 2022-01-27  

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