2023 Fiscal Year Final Research Report

Surface cleaning through dynamic meniscus wetting of dirt particles

Research Project

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Project/Area Number	20KK0085
Research Category	Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 19:Fluid engineering, thermal engineering, and related fields
Research Institution	Tokyo University of Science
Principal Investigator	Ueno Ichiro 東京理科大学, 創域理工学部機械航空宇宙工学科, 教授 (40318209)
Co-Investigator(Kenkyū-buntansha)	黒瀬築東京理科大学, 創域理工学部機械航空宇宙工学科, 助教 (30868740) 塚原隆裕東京理科大学, 創域理工学部機械航空宇宙工学科, 教授 (60516186)
Project Period (FY)	2020-10-27 – 2024-03-31
Keywords	界面熱流体力学 / メニスカス / 表面張力 / 動的濡れ
Outline of Final Research Achievements	We conducted series of experiments and numerical analysis specifically targeting cylinders, spheres, and ellipsoids as the microstructures with respect to "meniscus cleaning" mechanisms. In the case of the cylinders and the spheres, we successfully quantified the force field acting on microstructures in the process of meniscus formation around the microstructures through numerical analysis, and provided fundamental guidelines regarding the influence of shape in meniscus cleaning mechanisms. For the ellipsoids, we experimentally and numerically demonstrated that the meniscus shape varies with the angle of attack, and conducted preliminary analysis on the pressure field near the ellipsoids. We regularly held remote meetings with international collaborators and smoothly facilitated collaborative work using online environments for writing manuscripts. It must be noted that, due to the COVID-19 pandemic, we were unable to conduct joint experiments on-site.
Free Research Field	界面熱流体力学
Academic Significance and Societal Importance of the Research Achievements	微小構造物を有する基板上を濡れ拡がる液滴の挙動に関する研究は，特に洗浄機構への応用を目指して行われている．マイクロ流体力学の領域では，微小チップの作成により利用液体の少量化は出来るが，微小領域内で大きな流動抵抗に抗して液体を搬送する必要がある．そのため，多大なエネルギーを用いたポンプ駆動や，化学的・光学的処理を施し，任意の形状・間隔を持った親水性パターンを形成する必要があり，対象とする液体の必要量は微小ながらも，システムとして稼働するためのエネルギー消費・排出が甚大となっている．本研究成果により，メニスカス形成時の微小構造物に作用する力場の定量化を，形状・姿勢・濡れ性の影響を考慮して実現した．