Elucidation of the frost growth process by means of the heat and mass transfer analysis bases on the frost micro structure measurement by using X-ray micro CT
| Project/Area Number |
18K03994
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 19020:Thermal engineering-related
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| Research Institution | Kansai University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
小田 豊 関西大学, システム理工学部, 准教授 (50403150)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2020: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
Fiscal Year 2019: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2018: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
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| Keywords | 霜 / 氷結晶 / X線マイクロCT / ３次元微細構造 / 熱物質輸送 / 3次元構造 / 着霜 / 霜結晶 / X線μCT |
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| Outline of Final Research Achievements |
Frost formation on the heat exchangers of the air conditioning equipment causes the serious energy loss, thus the anti-frost formation technique is the urgent task. The purpose of this study is to clarify the frost growth process by estimating the relationship between the frost-crystal micro structure and the heat-mass transport phenomena in the frost layer. The three-dimensional microstructure of the frost crystal was measured using X-ray micro CT, and the effect of the cooling surface properties on the crystal structure was evaluated. Furthermore, the combined heat conduction of ice crystals and moist air in the frost layer was analyzed using the measured three-dimensional microstructure data. The surface temperature of the frost layer rises as the frost layer grows, while the temperature of the bottom of the frost layer decreases. As a result, ice crystals at the bottom of the frost layer grow by the water vapor supplied from the sublimation in the frost layer.
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| Academic Significance and Societal Importance of the Research Achievements |
空調機器の暖房運転において室外機の熱交換器で着霜が生じると，機器のエネルギー効率が30%近く低下することが報告されており，熱交換器の耐着霜の技術開発は重要な課題である．本研究は，霜結晶構造と霜層内の熱物質輸送との関係の解明により，霜成長過程を明らかにすることを目的とし，耐着霜性能を有する伝熱面の微細構造や表面処理性状の開発につながる基礎研究として位置づけられる．本研究結果により，はっ水性の冷却面表面では霜形成初期の氷滴の形成に影響し，霜結晶密度が疎となることが示された．さらに，氷結晶と湿り空気の複合熱伝導を解析した結果，霜層内の水蒸気輸送が霜層の発達に影響することが明らかとなった．
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Report
(4 results)
Research Products
(6 results)
