| Project/Area Number |
02452126
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Yokohama National University |
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Principal Investigator |
IIDA Yoshihiro Yokohama National Univ., Dept. of Mat. Sci. & Chem. Engng, Professor, 工学部, 教授 (90005299)
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| Co-Investigator(Kenkyū-buntansha) |
YAKASHIMA Takeo Yokohama National Univ., Dept. of Mat. Sci. & Chem. Engng, Research Assistant, 工学部, 助手 (40197091)
OKUYAMA Kunio Yokohama National Univ., Dept. of Mat. Sci. & Chem. Engng, Iecturer, 工学部, 講師 (60204153)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥5,800,000 (Direct Cost: ¥5,800,000)
Fiscal Year 1991: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1990: ¥4,800,000 (Direct Cost: ¥4,800,000)
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| Keywords | Boiling / Fluctuation Nucleation / High Speed Heating / Transient Boiling / Bubble Nucleation / Homogeneous Nucleation / Heat Transfer / Superheat Hmit / 超高熱流束 |
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| Research Abstract |
An extremely small flat heater is formed on a quartz glass plate by spattering platinum on it. The size is O. 1mm in width, 0.25mm in length and 0.25x10^<-3>mm in thickness. Extremely higher temperature rise rate as well as extremely larger heat flux is attained by supplying a small electric power input to this test section in comparing with those in ordinary boiling experiments. The experimental apparatus is composed of the pulse generator, the high-speed power amplifier, the instrumentation part such as the storage oscilloscope, the observation part -such as the microscope and others. The most suitable system for this experiments is examined and fixed.
A series of non-linear two-dimentional heat conduction simulation were conducted for evaluating the error of temperature measurements and for compensating it.
Experiments with pure water at atmospheric pressure were carried out at first. The temperature rise rate of 0.7x10^8 K/s and the heat flux over 10^8 W/m^2 were attained by heating
… More
the test section pufsewisely. At a higher temperature rise condition a large number of bubble generation, about 10^<10> n/m^2 at the maximum, was observed. These buubbles generate on the heater by a single effort and grow uniformly. The authors named this peculiar configuration as the cavierwise bubble generation. Further, it was shown that the temperature at the beginning of bubble generation approached to the homogeneous nucleation temperature of water in accordance with the increase of temperature rise rate.
Similar experiments were made for ethyl alcohol and toluen. The cavierwise bubble generation was also observed in these organic liquids and their temperatures at the beginning of bubble generation were shown to be almost equal to the respective homogeneous nucleation temperature. A series of theoretical calculation on the bubble number increase versus the lapse of time were made on the basis of the classical nucleation theory and it was shown that the experimental results were comparatively similar to the theoreticals. Thus, the bubble generation phenomenon represented by the cavierwise bubble generation was estimated to be due to the fluctuation nucleation. Less
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