| Project/Area Number |
03402030
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
KUROSAKI Yasuo Tokyo Institute of Technology, Dept.of Mechanical and Intelligent Systems Engineering, Professor, 工学部, 教授 (70016442)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Jun Tokyo Institute of Technology, Dept.of Mech. and Intelligent Systems Engineering, 工学部, 助手 (40210455)
SATOH Isao Tokyo Institute of Technology, Dept.of Mech. and Intelligent Systems Engineering, 工学部, 助教授 (10170721)
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| Project Period (FY) |
1991 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥16,800,000 (Direct Cost: ¥16,800,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1992: ¥5,900,000 (Direct Cost: ¥5,900,000)
Fiscal Year 1991: ¥9,600,000 (Direct Cost: ¥9,600,000)
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| Keywords | High-Temperature Gas-Solid Suspension Flow / Radiative Heat Transfer / Radiation Properties of Fluidized Particles / Radiative Penetration Depth / CO_2 Laser Heating / IR Thermography / Circulating Fluidized Particle Cell / Control of Void Fraction / 過冷却解除 / 微小液滴 / 交流電場加振 / マイクロ波励振 / 能動的制御 / 固気二相流 / 流動層 / 粒子挙動 / 空隙率 / 伝熱促進 / ふく射伝播機構 |
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| Research Abstract |
In the present research project, effects of the properties and behavior of the particles laden with a gas-solid suspension flow on the radiation heat transfer were examined. The results are summarized into the followings :
1. Penetration of Radiation within a Fluidized Particle Layr. First of all, radiation transfer from a surface immersed in a fluidized bed was experimentally examined ; a monochromatic laser light was projected into the fluidized particles through the surface, and intensity distributions of the laser light were measured within the particles. The results showed that the radiation penetration depth in the particle emulsion is relatively small, but that the radiation is hardly scattered by the "bubble phase" of fluidized particles. These results suggests that the radiation transfer from a heat transfer surface to fluidized particles is dominated by the relation between the thickness of thermal boundary layr on the surface and the radiation penetration depth of particles.
2
… More
. Radiation Emitted from the Fluidized Particles Adjacent to the Heat Transfer Surface. Radiation emitted from the fluidized particles adjacent to a heat transfer surface was measured by means of IR thermography ; fluidized particles were heated from a heat transfer surface, which was a transparent for the IR radiation, and intensity of the radiation emitted from the particles was measured by a IR thermo-camera. The results showed that the radiation emitted from the heated particles decreases with increasing the fluidizing gas flow rate, i.e. void fraction of the fluidized particles, and that the intensity of radiation increases as the fluidized particles become "black" for IR radiation. These results mean that the heat transfer augmentation due to radiation in a high-temperature gas-solid suspension flow is evident when the particles are dilute and transparent for radiation.
3. Experimental Evaluation of Radiation Heat Transfer in a Fluidized Bed. In order to confirm the results described above, radiation heat transfer between a high-temperature heat transfer surface and fluidized particles was experimentally examined ; particles of three different materials were used so as to examine the effects of particle emissivity. Heat transfer surfaces of two different emissivity, which were heated upto 1200 K, were used for evaluating the radiation heat transfer from the heat transfer surface. The experimental results showed that, under our experimental conditions, evident radiation heat transfer was observed only when the alumina particles, which are relatively transparent for IR radiation, were used. This result coincides well with the ones estimated in our stury described above. In addition to these, heat transfer of a circulating fluidized particle cell was examined so as to develop the control technique for void fraction distribution of the fluidized particles adjacent to the heat transfer surface, which dominates the radiative heat transfer from or to the fluidized particles. Less
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