1995 Fiscal Year Final Research Report Summary
Promotion of frost elimination applying super high-tension in a series of pulses
| Project/Area Number |
06650238
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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 | Gifu University |
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Principal Investigator |
KUMADA Masaya Gifu University, Faculty of Engineering, Professor, 工学部, 教授 (30021603)
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| Co-Investigator(Kenkyū-buntansha) |
HANAMURA Katsunori Gifu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (20172950)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Elimination of Frost / Pulsasive high-tension charge / Hest exchanger / Frost structure / Corona wind / Electric fields |
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| Research Abstract |
In order to promote the elimination and control against the growth of frost, it is examine to impress high voltage in a series of pulses.
In the first place, the effect of electric field on the frost formation around a tube in the uniform flow is studied phenomenologically. The electric field is applied between the surface and the mesh electrode. Removing of the frost from the surface depends on the structure of frost. The expected result of the electric field were obtained in the separation region.
In the second place, a NEOFLON-FEP thin film surface was used as a frosting surface. It could be expected that the frost may be removed from the surface more easily by applying the electric fields, because the bounding strength between the frost and surface becomes weaker than a copper surface was used as the frosting surface. The results reveal that the wettability of the surface is not affect the frosting weight process. However, frost height on a NEOFLON-FEP-film surface was formed lower than frost height on a copper surface.
Charge of high voltage has a highly inhibitory action against the growth of frost because it increases the Maxwell's stress and promote the growth of needle-shaped frost due to the nonisotropic growth occured by ordering of proton. But, when pulse frequency is large and pulse width is small, even charge of super high tension took no recognizable effect to the isotropic growth of frost. They are important factors on the control against the growth frost utilizing electric field.
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