| Project/Area Number |
14550857
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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 |
Aerospace engineering
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| Research Institution | High Energy Accelerator Research Organization (2004)
The High Energy Accelerator Research Organization (2002-2003) |
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Principal Investigator |
KIMURA Nobuhiro High Energy Accelerator-Research Organization, Cryogenics Science Center, 超伝導低温工学センター, 助手 (10249899)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAI Hirotaka High Enerfy Accelerator Research Organization, Accelerator Laboratory, Assistant researcher, 加速器研究施設, 助手 (00188872)
MURAKAMI Masahide University of Tsukuba, Institute of Engineering Mechanics and Systems, Professor, 大学院・システム情報工学科, 教授 (40111588)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | superfuid helium / superconducting temprature sensor / visualization observation / film boiling mode / pressure dependence / λ-pressure / weakly subcooled film boiling / noisy film boiling / λ点圧力 / シャドーグラフ / 透過式薄膜ヒーター / 表面張力波 / 光学窓 / 可視化法 / シュリーレン法 / ガスヘリウム界面 / 伝熱促進効果 |
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| Research Abstract |
The main result of this research would be arranged as follows
1) In the strongly subcooled state of the He II, the vapor layer was very thin and the behavior of the vapor layer was relatively stable. As pressure of the He II bath was decreased, the behavior of the vapor layer was intensified gradually and the relatively stable area was diminished. And in the weakly subcooled state of the He II, the thickness of the vapor layer was increased as the decrease of the pressure of the bath. In the case of the pressure adjacent to λ-pressure, it was confirmed that the boiling state changed from stable boiling to unstable boiling. This boundary was confirmed in the pressure higher than 1-pressure.
2) The subcooled and the silent film boiling in the He II are the same boiling mode and these film boiling modes are identical to the normal film boiling that occurs in common fluids. And the noisy film boiling in the He II is a kind of large-scale unstable phenomenon that generates the large oscillation in the heater temperature and the heat transfer coefficient, and it is the characteristic boiling mode in He II
3) The boundary between the weakly subcooled and the noisy film boilings in He II exists just above λ-pressure. This boundary increases as the He II temperature decreases or the heat flux increases.
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