| Project/Area Number |
13650162
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | MURORAN INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
KAZAMA Toshiharu Muroran Institute of Technology, Dept of Mechanical Systems Engineering, Associate Professor, 工学部, 助教授 (20211154)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Atsushi Yokohama National University, Professor, 工学部, 教授 (40017885)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2001: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Cavitation / Erosion / Biodegradable oils / Tap water / Mineral oils / Fluid power systems / Positive displacement pumps and motors / Environment / 生分解性作動液 |
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| Research Abstract |
By utilizing submerged cavitating jet rigs, the experiment of cavitation erosion was conducted. Tap water, synthetic biodegradable oil with VG46 or mineral hydraulic oils with VG32 or VG46 was alternatively used as the test liquid. The liquid temperature was kept at 40 to 65℃. The upstream pressures were specified as 10 to 18 MPa and the cavitation numbers were 0.02 to 0.04. The stand-off distance was varied from 7.5 to 35mm. Specimens were made of aluminum alloy and the diameter was 15mm. A sharp-edged long orifice nozzle with the diameter of 1mm and the length of 4mm was prepared. The mass loss and cross-sectional profiles of the specimens were measured and the tune evolution of erosion was evaluated. In parallel, the cavity-clouds of the jets were observed and recorded with video cameras ; subsequently, the existence-probability distributions of the clouds were obtained by picture processing techniques.
The mass loss by tap water was largest, followed by the mineral oil with VG32, the oil with VG46 and the biodegradable oil. The difference in the mass loss was marked as the cavitation number became smaller. As the liquid temperature was higher, the loss was larger for all liquids. The discrepancy was notable as the temperature became lower. The types of oils less influenced essentially the relation between the stand-off distance, the upstream pressure and the cavitation numbers and the mass loss and the erosion-ring diameter as well as the stand-off distance where the mass loss maximized. The region of a certain existence-probability of the clouds and the location where the surface was eroded severely coincided. The cavitatingjets lengthened and the mass loss increased as the cavitation number became smaller.
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