1995 Fiscal Year Final Research Report Summary
Heat Transfer, Relationship Between Erosion and Particle Cluster in the Multiphase Flow
| Project/Area Number |
06650251
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Yamaguchi University |
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Principal Investigator |
KATOH Yasuo Yamaguchi University, Mechanical Engineering, Associate Professor, 工学部, 助教授 (50152749)
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| Project Period (FY) |
1994 – 1995
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| Keywords | MULTIPHASE FLOW / FLUIDIZED BED / EROSION / PARTICLE CLUSTER / HEAT TRANSFER / VISUALIZATION / HIGH SPEED VIDEO / IMAGE ANALYSIS |
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| Research Abstract |
In order to know the heat transfer, relationship between erosion and particle cluster in the multiphase Flow (namely circulating fluidized bed (CFB) ) , the typical approach on the image processing of the image data such as spatial filtering method (SFM) for estimating of the particle velocity and the heat transfer mechanism from a fine wire to a particle for measuring the heat transfer coefficient around a horizontal fine platinum wire, which was heated electrically in a CFB,has been done experimentally.
[1] Image analysis for estimating of the particle velocity in a CFB,
(1) The clear and local particle velocity distributions for the various superficial gas velocity and the various circulating particle flow rate were obtained.
(2) The characteristics of particle flow varied with the change of the superficial gas velocity and the change of the circulating particle flow rate in this fluidization region (fast fluidization region).
(3) The particle velocity distribution obtained by SFM with
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the mean particle velocity from the measuring particle hold-up and with the particle velocity distributions obtained by optical fiber cross-correlation method and also with the velocity distribution obtained by eye observation were compared. Those values agreed very well each others in the experimental conditions.
(4) The applied limitation of this SFM for measuring the particle velocity was obtained the particle velocity only below the value of the above equation in density.
[2] Heat transfer mechanism in a CFB
(1) The relationship between the particle behavior and the characteristics of heat transfer around a horizontal fine wire in CFB was influenced by the flow patterns such as the turbulent fluidization and the dilute fluidization.
(2) This mechanism also influenced by the particle density which coincided with the particle packing ratio. In the turbulent fluidization region, the heat transfer coefficient for dp<dw was larger than that for dp>dw.
(3) The relationship between the gas velocity and the characteristics of heat transfer around a horizontal fine wire in the dilute fluidization. This seemed to be the reason why the heat transfer coefficients were the something effects by the difference of direct contact area between the particle and the fine wire which corresponded to the ratio of the particle size to the fine wire size roughly. Less
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Research Products
(12 results)
