Investigation and modelling of complex flow with phase change in microchannels

• Project/Area Number: 18K03976
• 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: Kyoto University
• Principal Investigator: Matsumoto Mitsuhiro 京都大学, 工学研究科, 准教授 (10229578)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2018: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: 流体相変化 / マイクロスケール流れ / 蒸発 / 沸騰 / パターン形成 / マイクロ流路 / 流れの可視化 / 表面粗さ / マイクロチャネル / 可視化実験 / imbibition / 混相流

Outline of Final Research Achievements

We have experimentally investigated evaporation and flow dynamics of liquid sandwiched between solid plates under reduced pressure to study the mechanism of vapor washing process of laminated plates in electric transformers. Water, ethanol, and several organic compounds were used as test liquids, and glass plates with specific surface roughness, fabricated with a sand-blast gun, were adopted to visualize the flow dynamics. We found that the surface roughness is one of the dominant factors for flow dynamics. Relation between the flow in the rough channel and the imbibition process was discussed.

Academic Significance and Societal Importance of the Research Achievements

マイクロチャネル内の流動の研究は，nmオーダーまで壁面を平滑にした流路とスペーサー
を用いて行われることがほとんどだが，本研究では，逆にサンドブラストにより1μm～10μm程度の粗さを設けた壁面間の流動を対象にした．これは，問題の発端が変圧器の鉄心に使われる積層鋼板からの絶縁油除去のメカニズム解明にあるからである．これにより壁面粗さの影響を定量的に解析することができ，新たな応用への道が拓けた．

Research Products

• [Journal Article] Fluid Motion during Evaporation in Rough Thin Gap (2020)
  • Author(s): K. Nagashima, E. Mae, H. Wakabayashi, M. Matsumoto
  • Journal Title: Applied Sciences Volume: 5 Pages: 1-12
  • Peer Reviewed / Open Access
• [Presentation] Fluid Motion and Phase Change in Thin Gap (2019)
  • Author(s): D. Xu, K. Nagashima, M .Matsumoto
  • Organizer: Heat Transfer, Fluid Mechanics and Thermodynamics
  • Int'l Joint Research
• [Presentation] Fluid Motion and Evaporation Dynamics in Rough Thin Gap (2019)
  • Author(s): M. Matsumoto, K. Nagashima, D. Xu
  • Organizer: 2nd Pacific Rim Thermal Engineering Conference
  • Int'l Joint Research
• [Presentation] Fluid motion and phase change in thin gap (2019)
  • Author(s): D. Xu, K. Nagashima, M. Matsumoto
  • Organizer: 14th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics
  • Int'l Joint Research
• [Presentation] Evaporation and boiling in thin gap (2018)
  • Author(s): D. Xu, K. Ogawa, M. Matsumoto
  • Organizer: 16th International Heat Transfer Confefence
  • Int'l Joint Research
• [Presentation] Motion of liquid sandwiched between rough surface plates (2018)
  • Author(s): D. Xu, M. Matsumoto
  • Organizer: 29th International Symposium on Transport Phenomena
  • Int'l Joint Research