Investigation of the droplet inner flow induced by adjacent droplet evaporation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03898
• 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: Okayama University
• Principal Investigator: Yamada Yutaka 岡山大学, 環境生命自然科学学域, 講師 (60758481)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 液滴蒸発 / 対流 / 温度分布

Outline of Final Research Achievements

In the present study, inner flow in a droplet induced by evaporation of multi-droplets was experimentally observed and multi-droplets evaporation was numerically analyzed to show an evaporation flux from the droplet surface. At the case of two water droplet evaporation, liquid flow which directed from near side to far side of three-phase contact line along to liquid-gas interface was observed. From numerical approach, evaporation suppression was predicted at vicinity region between two droplets and accordingly, latent heat transfer was also suppressed. This result was confirmed by the observation using an infrared camera. At the case of solvent droplet placed next to water droplet, liquid flow driven by solutal Marangoni effect was observed and a difference of solubility of organic solvent affected to the flow behavior in the water droplet.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

液滴の蒸発は雨粒やインクジェット印刷など日常生活でも広くみられるが，1液滴での挙動把握が先行し，複数の液滴が近接して存在する場合の研究が進んでいなかった．本研究では液滴同士が近接する場合の液滴内対流が1液滴の場合と異なることを示し，数値解析の結果から近接部分での蒸発抑制とそれに伴う温度低下の抑制がこの挙動を引き起こしていることを示唆する結果を得た．このことは複数の液滴が近接する環境での蒸発を理解するために役立つと考えられる．