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Determination of Convection Heat Transfer Coefficient Considering Curing Condition, Ambient Temperature and Boiling Effect
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 Title & Authors
Determination of Convection Heat Transfer Coefficient Considering Curing Condition, Ambient Temperature and Boiling Effect
Choi Myoung-Sung; Kim Yun-Yong; Woo Sang-Kyun; Kim Jin-Keun;
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 Abstract
The setting and hardening of concrete is accompanied with nonlinear temperature distribution caused by development of hydration heat of cement. Especially at early ages, this nonlinear distribution has a large influence on the crack evolution. As a result, in order to predict the exact temperature history in concrete structures it is required to examine thermal properties of concrete. In this study, the convection heat transfer coefficient which presents thermal transfer between surface of concrete and air, was experimentally investigated with variables such as velocity of wind, curing condition and ambient temperature. At initial stage, the convection heat transfer coefficient is overestimated by the evaporation quantity. So it is essential to modify the thermal equilibrium considered with the boiling effect. From experimental results, the convection heat transfer coefficient was calculated using equations of thermal equilibrium. Finally, the prediction model for equivalent convection heat transfer coefficient including effects of velocity of wind, curing condition, ambient temperature and boiling effects was theoretically proposed. The convection heat transfer coefficient in the proposed model increases with velocity of wind, and its dependance on wind velocity is varied with curing condition. This tendency is due to a combined heat transfer system of conduction through form and convection to air. From comparison with experimental results, the convection heat transfer coefficient by this model was well agreed with those by experimental results.
 Keywords
thermal property;convection heat transfer coefficient;velocity of wind;ambient temperature;boiling effect;
 Language
Korean
 Cited by
1.
뿜칠피복재를 사용한 고강도 콘크리트 부재의 내화피복두께에 관한 실험적 연구,이태규;

한국화재소방학회논문지, 2010. vol.24. 4, pp.41-46
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