| Project/Area Number |
63850037
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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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 |
KOBAYASHI Ryoji Tohoku Univ., Faculty of Engineering, Professor, 工学部, 教授 (70006170)
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| Co-Investigator(Kenkyū-buntansha) |
IBUKI Seita Dengyosha Machine Works, LTD, Head of Section, 技術企画課長
SHOJI Tetsuo Tohoku Univ., Faculty of Engineering, Professor, 工学部, 教授 (80091700)
TAKAYAMA Kazuyoshi Tohoku Univ., Inst. of Fluid Science, Professor, 流体科学研究所, 教授 (40006193)
SHIMA Akira Tohoku Univ., Inst. of Fluid Science, Professor, 流体科学研究所, 教授 (30006168)
新井 隆景 室蘭工業大学, 助教授 (10175945)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥13,000,000 (Direct Cost: ¥13,000,000)
Fiscal Year 1989: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1988: ¥9,600,000 (Direct Cost: ¥9,600,000)
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| Keywords | Fluid Mechanics / Jet / Water Jet / Cutting Processing / Impact Fracture / Nozzle / Multiphase Flow / ウォータージェット / 破壊 |
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| Research Abstract |
The following research was carried out to make the water jet technology in practical use.
1. Jet Cutting Robot A robot for jet cutting was designed and manufactured. A nozzle head issuing a high speed water jet can be traversed in three-dimensional directions at definite speed, which is computer-controlled. Test materials are processed in arbitrary shape by the water jet issued vertically.
2. Development of High Performance Nozzle The design of the contraction nozzle issuing the high speed water jet is one of the important factors which influence the cutting performance directly. We therefore found experimentally the most suitable profile of the nozzle inner surface after many tests in a wide range of the main parameters determining the nozzle profile. It was also clarified that the finishing accuracy of the cylindrical inner surface near the nozzle exit is related very sensitively to the structure of the water jet and also the stable performance of cutting process.
3. Structure of Water Jet The structure of the water jets issued from some test contraction nozzles and orifices was compared in detail by using a shadow photograph method of 0.8mus flash time. It was also found that the addition of polyner into water suppresses remarkably the atomization of the water jet and increases the cutting performance about 3.7 times in a case of 1000 ppm compared with a pure water jet.
4. Mechanism of Cutting Process by Water Jet It was made clear that the mechanism of the water jet cutting is the water hammer phenomenon occurred by the water drop impact and the impacting fracture of the solid material. In the case of abrasive jet which is mixed abrasives with water jet, the high speed impact of the solid particles causes mainly the cutting process. We found that the supersonic air jet has a possibility as cutting tool for soft solid materials.
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