| Project/Area Number |
14580540
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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 |
Nuclear engineering
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| Research Institution | Ibaraki University |
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Principal Investigator |
KAMINAGA Fumito Ibaraki University, the college of Engineering, Professor, 工学部, 教授 (80114015)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMURA Kunihito Ibaraki University, the College of Engineering, Research Associate, 工学部, 助手 (00291287)
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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 |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2002: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Two-phase thermosyphon / Boiling heat transfer / Maximum heat flux / Condesation heat transfer / Decay heat / Passive system / 静的機器 / 沸騰熱伝導 / パッシブ |
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| Research Abstract |
A special type thermosyphon, a looped parallel thermosyphon referred to LPT, has been developed for obtaining better heat transfer performance than a conventional single tube thermosyphon referred to STT. The LPT consists of two STTs joined each other at top and bottom by two U-tubes. The purpose of this study is to obtain fundamental knowledge regarding to heat transfer characteristics of the LPT in order to apply it to a passive heat decay removal system of a nuclear reactor. Effects of fill charge ratio and system pressure on the heat transfer and effect of flow fluctuation in the condenser part on condensation heat transfer in the presence of non-condensable gas are mainly examined. Experiments are conducted with water and ethanol working fluids in wide ranges of system pressures of 23 to 144 kPa for ethanol and 12 to 57 kPa for water, charge ratio of 0.3 to 0.9 and coolant temperatures of 25 to 50 ℃. Experiments using a STT are also conducted to compare with the heat transfer characteristics of the LPT on the same conditions.
Major findings of the experiments are as follows : In the evaporator part, the wall temperature profile is more uniform than that in the STT and the heat transfer coefficient is similar between LPT and STT. The maximum heat flux obtained in the LPT excluding a noncondensable gas is three to four times larger than that in STT for both working fluids. But including the gas it falls down to a lower value than that in STT. The reason of the decrease is not clear and has been remained to be investigated. The effect of fluid fluctuation in the bottom U tube on the condensation heat transfer is minor and the effect of the noncondensable gas on the condensation heat transfer can not be minimized by the fluid flow fluctuation which was expected before the experiments.
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