| Project/Area Number |
08455098
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | MURORAN INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
HANAOKA Yutaka Muroran Inst.Tech., Mechnical Eng., Proffesor, 工学部, 教授 (60002870)
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| Co-Investigator(Kenkyū-buntansha) |
TOKURA Ikuo Muroran Inst.Tech., Mechnical Eng., Asso.Proffesor, 工学部, 助教授 (00002931)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1996: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | Flashing / Rapid Depressurization / Mist Formation / Pressure-Undershoot / Pressure Recovery / Boiling |
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| Research Abstract |
In the former study related to this research projects, it was pointed out that when liquid was subjected to a rapid reduction of pressure such as a breakdown of cryogenic storage tanks or pipes, a denser mist layr was formed over the liquid surface of vessel in case of extremely high depressurization rates, and that gave a strong influence to a boiling behavior to occur after that. So, in this study, flashing experiments on the relationship between the mist formation and boiling phenomenon was conducted by using the high speed video-camera being purchased during an initial year. And also an attempt have been made to clear the condition of inception of bubble formation under the rapid depressurization processes. In addition, these results are applied to the estimation of their quantities of pressure undershoot and pressure recovery due to the vapor generation along with the liquid boiling in comparison with the numerical simulation model.
Results obtained through this research project ar
… More
e summarized as follows
1.Experiments were carried out by using two kinds of vessel having the state of different wall roughness. As its result, it was observed that there are remarkable differences in both of pressure transients and mist growth rates even though the same condition. This can be considered due to the effects of the amount of preexsting nuclear sites on the wall surface.
2.As a formation of thermal stratification in cryogenic liquid and making a high temperature of wall surface has not been avoidable because of the imperfect adiabatic wall caused by heat penetration (heat conduction, convection and radiation etc.) from the surroundings, a dependency of the wall charatevistics on the incipient condition of bubble formation appears strongly in comparison with those of normal or high temperature liquid in stored state.
3.The transient pressure changes of the pressure-undershoot and the recovery pressure followed after that within the container may be determined by the mass balance between the vapor delivery rates through the orifice (corresponds to the breakdown and leakage area of vessel and pipes) and the explosive vapor generation rate after its depressurization process. Less
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