2022 Fiscal Year Final Research Report
Similarity of a splash at high Ohnesorge liquid drop impact on a solid surface
| Project/Area Number |
20H02061
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 19010:Fluid engineering-related
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
小林 一道 北海道大学, 工学研究院, 准教授 (80453140)
藤井 宏之 北海道大学, 工学研究院, 助教 (00632580)
真田 俊之 静岡大学, 工学部, 教授 (50403978)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 液滴衝突 / 液膜流れ / スプラッシュ / 不安定性現象 / 高オーネゾルゲ液滴 |
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| Outline of Final Research Achievements |
Liquid droplet impacts on the solid surface are critical in technical applications, such as ink-jet printing and semiconductor cleaning. After droplet impacts on a solid surface, splash, which consists of the secondary droplets ejected from the edge of the lamella, may be generated. Although a wide variety of parameters that control splash formation after the droplet impact are proposed, the dynamics of the droplet after the impact are yet fully understood. Therefore, we investigated the flow instabilities that occur at the impact of a high Oh liquid drop with high viscosity and a small radius on a solid surface. We conducted four types of experiments: observation of viscous liquid drop impact on a smooth solid surface, observation of wetting failure at drop impact on a solid surface with various wettability, observation of thin-gas layer by colour interferometry, and observation of high-speed droplet impact on a rough surface in the reduced pressure chamber.
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| Free Research Field |
流体力学
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| Academic Significance and Societal Importance of the Research Achievements |
液滴の固体表面衝突後に，液滴の一部は変形し固体表面上を液膜として進展する．衝突速度が十分大きい場合には，液膜周縁部の流れが不安定となり，周縁部から二次液滴が発生する．本研究を遂行することにより，水と比較して10 - 20倍の高粘度の液滴の場合には，低粘度液滴衝突では観察されない種類の二次液滴が発生することを明らかにした．また，二次液滴発生には，固体表面の濡れ性・表面粗さが大きく影響を及ぼすことを明らかにした．液滴と固体面との衝突は，噴霧塗装，スプレー乾燥，インクジェット印刷等の様々な産業分野におけるプロセスにおいて本質的に重要な物理過程であるため，これらの産業分野の新たな展開に寄与する
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