3D thermal/flow measurement for active control of internal flows in drops

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K14667
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Kyushu University
• Principal Investigator: Kita Yutaku 九州大学, 工学研究院, 助教 (40840616)
• Project Period (FY): 2020-04-01 – 2022-03-31
• 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

Outline of Final Research Achievements

Heat transfer and fluid dynamics of locally-heated drops have been investigated with an aim to develop drop-base microreactors for lab-on-a-chip devices. Drops can be heated either with a laser or microheaters. Surface tension gradients would be formed due to the artificial thermal gradients produced by localized heating, and then, the surface tension gradients would drive the flows within the drop, Criteria for the onset of the flows and parameters that determines the flow have been identified. Moreover, the evaporation of "neighbouring" drops has been studied, which is usually the case in most applications. Background-oriented Schlieren technique has been used to quantify the vapour concentration field between drops and the interaction between them.

Free Research Field

熱流体工学

Academic Significance and Societal Importance of the Research Achievements

本研究は液滴の新規機能創出を目指した基礎現象の解明を目指すものである。液滴は一見単純な系に思われるが、実際は蒸発現象、濡れ現象、伝熱および流動現象など数々の現象が複合的に起こる複雑な系である。これまでにもスプレー冷却やインクジェット印刷、コーティング技術において液滴は基礎的な要素として用いられてきたが、これらは基本的に前述の諸現象の自発的な結果を応用したものである。一方で、本研究ではこれらの現象を能動的に制御しようとするものであり、得られた知見は学術的に価値が高く、液滴を利用した新技術の創出に大きく貢献するものである。