2023 Fiscal Year Final Research Report
High-speed video image analyses on actions of sand particles in a water jet obliquely impinging against a solid surface
| Project/Area Number |
21H01443
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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 22040:Hydroengineering-related
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| Research Institution | Kindai University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
江藤 剛治 大阪大学, 大学院工学研究科, 招へい教授 (20088412)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 水力発電 / 混相流 / 噴流 / 粒子 / ジェット / 高速ビデオカメラ / 近赤外 |
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| Outline of Final Research Achievements |
Surfaces of pipes and vanes of hydraulic power facilities are damaged by fine sand particles carried by water. The following three approaches were used to analyze the motions of water and a sphere closely approaching to a solid plate: (1) numerical analyses, (2) hydraulic experiments, and (3) development of a flow visualization technique in a very thin space with illumination of SWIR light. The last one is a new technology developed specific to this research. For example, when a transparent water tank is illuminated from the bottom or surface with 1,400-nm light, fine tracer particles can be visualized in a very thin layer of less than 1 mm from the bottom or surface, and the rest of the water body is seen as completely darkness. By selecting the wavelength of the illumination, the water motion in the layer of any thickness can be uniquely visualized and analyzed, which is very useful in experimental analyses of motions of water when a sphere is closely approaching a solid surface.
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| Free Research Field |
水工水理学
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| Academic Significance and Societal Importance of the Research Achievements |
非常に狭い間隙におけるダイナミックな水運動の実験的評価は，微細な砂粒子による発電設備の摩耗の問題だけでなく，産業上の様々の技術で遭遇する課題である．10μm以下の微細な砂粒子は表面の帯電に吸引された水膜に保護されて，流路の固体壁面に与えるダメージは抑制されているものと予想される．それより少し大きい粒子については，粒子と固体壁面が近接することにより潤滑効果が働くと考えられる．このような現象について水運動を直接可視化することは困難であった．本研究で開発したSWIR光を使った界面近傍の水運動の可視化技術は，固体壁面近傍だけでなく，自由表面を持つ水面近傍の水運動の研究を含めて有効な研究手段になる．
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