2003 Fiscal Year Final Research Report Summary
RESEARCH ON PREDICTION METHODS OF HEAT TRANSFER COEFFICIENT AND CRITICAL HEAT FLUX IN BOILING OF MULTICOMPONENT MIXTURES
| Project/Area Number |
14550187
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
FUJITA Yasunobu KYUSHU UNIVERSITY, Faculty of Engineering, Professor, 大学院・工学研究院, 教授 (90037763)
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| Co-Investigator(Kenkyū-buntansha) |
UCHIDA Satoru KYUSHU UNIVERSITY, Faculty of Engineering, Research Associate, 大学院・工学研究院, 助手 (80038041)
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| Project Period (FY) |
2002 – 2003
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| Keywords | Multicomponent mixture / Nucleate boiling / Heat transfer coefficient / Critical beat flux / Correlations / Marangoni number / マランゴニ数 |
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| Research Abstract |
(1)Heat transfer coefficients in nucleate boiling of mixtures were measured for various two-component mixtures and three-component mixtures. It was found from the measured data analysis that the reduction of heat transfer coefficient compared to the ideal coefficient estimated from heat transfer coefficient of mixture components is deeply related to the boiling range. Thus by taking into account the boiling range as a key parameter the heat transfer correlation was developed. The developed correlation succeeded to reproduce the measured heat transfer coefficients of two-and three-component mixtures within ±25% errors.
(2)Measurement of critical heat flux was performed for seven two-component mixtures. It was found that critical heat flux is either increased or decreased in 'a comparison of the ideal critical heat flux interpolated between the critical heat fluxes of mixture components. Positive mixtures provided the increased critical heat flux, while negative mixtures gave the decreased critical heat flux. Such a behavior of critical heat flux depending on the mixture property was concluded as the result of Marangoni force acting on thin film surface formed between the coalesced bubble and the heating wall. In order to realize such critical heat flux mechanism of mixtures the dimensionless Marangoni number was introduced, resulting in successful development of an empirical correlation for critical heat flux in mixture boiling.
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