| Project/Area Number |
12650192
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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 |
Thermal engineering
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| Research Institution | CHIBA UNIVERSITY |
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Principal Investigator |
HISHIDA Makoto CHIBA UNIVERSITY, FACULTY OF ENGINEERING, PROFESSOR, 工学部, 教授 (10291296)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Tetsuo JAPAN ATOMIC ENERGY RESEARCH INSTITUTE, DEPARTMENT OF NUCLEAR POWER USAGE, 核熱利用研究部, 主任研究員
FUMIZAWA Hotoo JAPAN ATOMIC ENERGY RESEARCH INSTITUTE, INTERNATIONAL NUCLEAR POWER CENTER, 国際原子力総合センター, 主任研究員
TANAKA Gaku CHIBA UNIVERSITY, FACULTY OF ENGINEERING, ASSISTANT, 工学部, 助手 (20292667)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | EXCHANGE FLOW / NATURAL CONVECTION / COUNTER FLOW OF TWO GAS IN A DUCT / MOLECULAR DIFFUSION / REDUCTION OF EXHANGE FLOW RATE |
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| Research Abstract |
This study deals with the method to reduce the exchange flow thorough a broken pipe which is connected to a tank containing dangerous gas like toxic or inflammable gas. The air-inflammable gas exchange flow during the pipe rupture accident is caused by natural convection driven by density difference.
In the first part of this study we performed experiment and numerical calculation thorough a rectangular pipe and round pipes. We visualized flow pattern and measured exchange flow rate, velocity distribution of the exchange flows. Experimental parameters are the inclination angle of the pipe and the combination of gases. That is, we investigated He-Air exchange flow, Ar-Air exchange flow and SF_6-Air exchange flow, and the inclination angle was varied in the range of 0 to π/2 radian. The velocity profile, concentration profile and exchange flow rate investigated by Numerical calculation of He-Air exchange flow through a rectangular channel were.
In the second part of this study, we investigated the He-Air and Ar-Air exchange flows thorough a round pipe which has a U-shape part in the middle. We visualized the flow pattern and measured the exchange flow rate.
The following main results were obtained
(1) Three flow patters were observed in the present experimental range of Grashof number, inclination angle and the combination of two gases. They are two-layered counter flow, three layered counter flow and swirling exchange flow.
(2) Empirical equations predicting the exchange flow rate were derived by the dimensional analysis
3) It was found that the exchange flow rate was reduced by a factor of 40 to 100 by installing the U-shape part in a round pipe. It was demonstrated that installing the U-shape part is very effective for the reduction of exchange flow rate
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