Investigation of elementary processes of cavitation inception in high-speed ultrapure water based on bubble dynamics
| Project/Area Number |
17K14596
|
|---|
| Research Category |
Grant-in-Aid for Young Scientists (B)
|
| Allocation Type | Multi-year Fund |
|---|
| Research Field |
Fluid engineering
|
|---|
| Research Institution | Miyakonojo National College of Technology |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2017-04-01 – 2020-03-31
|
| Project Status |
Completed (Fiscal Year 2019)
|
| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
|
|---|
| Keywords | 高速超純水用小型キャビテーションタンネル / キャビテーション流れのCFD解析 / 張力 / 気泡力学 / 初生理論 / 核生成 / 液体の張力 / 負圧 / 均質核生成 / 流体 / 流体工学 |
|---|
| Outline of Final Research Achievements |
Elementary processes of cavitation inception were investigated near a circular cylinder installed in high-speed water and oils. The non-circulation type of cavitation tunnel was constructed so that experimental conditions suitable for the inception study could be realized in the tunnel; (i) several cavitation nuclei are formed at a separation point on the cylinder due to tension, (ii) cavitation occurs only one time in each run, and (iii) size of solid particles and air contents in liquids can be controlled. We classified cavitation patterns into three types, by which the experimental conditions were found. Occurrence of tension in water behind the cylinder was clarified by CFD. Furthermore, the growth of a bubble in still liquids were theoretically investigated to forecast a radius attained during the negative pressure and, after that, a maximum radius attained under the successive atmospheric pressure.
|
| Academic Significance and Societal Importance of the Research Achievements |
①高速超純水用小型キャビテーションタンネルは，水中に不純物や浮遊気泡を含まない状態で張力により気泡核を発生させることができ，当該分野では最初の装置である．②非平衡蒸発と気泡の並進運動を考慮した気泡力学の基礎方程式をCFD解析で得られた流れ場で解いた研究はこれまでなされたことがない．③気泡核発生，成長，離脱，並進運動を観測し，初生に至るまでの素過程を実験及び理論の両面から解明する．④初生に及ぼす溶存空気及び水温の影響を明らかにする．⑤初生の素過程の解明をとおして，実際の流体機器内での初生機構及びキャビテーション流れのモデル化に指針を与えることができる．
|
Report
(4 results)
Research Products
(10 results)
