1987 Fiscal Year Final Research Report Summary
Fluid Dynamic Aspect in the Heat Removal near the Spacer of the Fuel Rods of a Nuclear Reactor
| Project/Area Number |
61550131
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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 |
Fluid engineering
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| Research Institution | Kyushu University |
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Principal Investigator |
FUKANO Tohru Kyushu University, Faculty of Engrg. Professor, 工学部, 教授 (60037968)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Two-phase flow / Film flow / Spacer / Obstacle / Fuel rod |
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| Research Abstract |
In this research project (1) flow mechanism of a thin liquid film flowing concurrently with a high speed gas flow, (2) mechanism of a large disturbance wave generation, and (3) the interaction between a flat-plate type flow obstruction with a cylindrical projection and a thin liquid film, are investigated. The results are summarized as follows; (1) Although the film Reynold's number was 150 at the most in this research, the film flow is laminar only in the very narrow region close to the duct wall due to the momentum exchange between a gas flow and surface waves. Then the temperature boundary layer becomes extremely thin and the liquid film is easy to break by the accerelated evaporation. (2) The disturbance wave, which plays an important role in the formation of a liquid film, is generated when the velocity of the particles exceed that of thd wave at the interface. The boundary of the existence of the disturbace wave depends strongly on the pipe orientation in the low gas velocity region. (3) The projection attached to the flat plate has a strong effect on the liquid film breakdown, while the flat plate without a projection is effective to keep a thin liquid film near the obstacle. In the case with the projection three types of the film breakdown are observed, i.e (a) the upstrem-side film breakdown due to a horse shoe vortex just in front of the projection, (b) the downstream-side film breakdown extending far downstream of the obstacle and (c) the downstream-side film breakdown limited within the gap of the obstacle. These three types of the film breakdown will be a main factor to restrict the maximum heat removal of the nuclear reactor.
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