1989 Fiscal Year Final Research Report Summary
Mechanism of Generation of High Speed Liquid Jet Driven by High Pressure due to Underwater Shock Wave Focusing and Its Application
| Project/Area Number |
63460088
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fluid engineering
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
TAKAYAMA Kazuyoshi Tohoku Univ., Institute of Fluid Science, Professor, 流体科学研究所, 教授 (40006193)
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| Co-Investigator(Kenkyū-buntansha) |
KUWAHARA Masaaki Tohoku Univ., Medical School, Associate Professor, 医学部, 助教授 (50006780)
SUGIYAMA Hiromu Muroran Institute of Technology, Professor, 教授 (70002938)
KOBAYASHI Ryoji Tohoku Univ., Faculty of Technology, Professor, 工学部, 教授 (70006170)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Shock Wave Focusing / Liquid Jet / High Pressure / Underwater Shock Wave / Cavitation / PVDF Pressure Gauge / Microexplosive / Holographic Interferometry |
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| Research Abstract |
An experimental attemp was made to produce a pulsed high-speed liquid jet driven by ultra high pressure generated during underwater shock wave focusing.
A numerical simulation was also carried out to know the flow field concerned in detail, especially to make clear the process of high pressure generation. Much efforts had been performed in order to produce an ideally spherical underwater shock wave by using a microexplosive. As a result, we succeeded in getting a maximum pressure higher than 8,000bar with 100mg PETN ignited by 10mg silver azide.
Based on the data obtained from a preliminary experiment, we tritato produce a high-speed liquid jet, driven by a high pressure of about 2,100bar. The high pressure occurred at the second focal point of an ellipsoidal cavity with the major and minor axes of 212mm X 150mm, due to focusing of an underwater shock wave, which was generated by igniting 10mg silver azide placed at the first focal point of the cavity. If a circular pipe with a nozzle, provided at an outer side of the ellipsoidal cavity, is set at the second focal point, we can obtain a high-speed, pulsed, liquid jet through this nozzle.
We measured stagnation pressure due to impact of the jet by means of a home -made PVDF pressure gauge, and obtained it as the maximum value of about 90bar and pulse width of 2mus. The corresponding impact velocity of a liquid jet can be estimated as about 130m/s.
A pulsed liquid jet has such excellent feature that working space and time are extremely small and short (2-3mus), so that its application to medical and other scientific fields should be promoted in the near future.
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