| 竖直圆管内超临界压力煤油传热特性实验研究 |
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| 作者姓名： | 胡江玉 周进 潘余 王辉 王宁 任春雷 |
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| 作者单位： | 国防科学技术大学航天科学与工程学院, 湖南长沙 410073 |
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| 基金项目： | 国家自然科学基金11372348 |
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| 摘 要： | 在压力2.5~4 MPa, 质量流量0.7~1.7 g/s, 热流密度0.06~1 MW/m2的实验条件下, 对煤油在内径1 mm, 长度300 mm竖直上升圆管内的流动与传热特性开展了实验研究, 并分析了传热系数随局部油温的变化及不同实验参数对传热的影响.结果表明, 超临界压力下煤油传热主要由自身物性和流动状态决定.超临界压力煤油传热过程大致可以分为3个区域:正常传热区传热强化区和传热恶化区.传热强化主要是湍流掺混增强和近壁面流体在拟临界温度附近物性剧烈变化的综合作用; 传热恶化则是因为壁温及近壁面流体温度远高于拟临界温度, 在近壁面发生了类似于亚临界状态下的“拟膜态沸腾”.
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| 关 键 词： | 流动状态 物性变化 传热恶化 传热强化 |
| 收稿时间： | 2016-05-06 |
Experimental Investigation on Heat Transfer of Kerosene Flowing in a Vertical Tube at Supercritical Pressure |
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| Affiliation: | College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China |
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| Abstract: | The flow and heat transfer characteristics of kerosene flowing in a vertical upward circular tube were experimentally investigated. The tube is 1 mm in diameter and 300 mm in length. Pressure ranges from 2.5~4 MPa, mass flow rate ranges from 0.7~1.7 g/s, and heat flux ranges from 0.06 ~ 1 MW/m2. Analysis was done to find out how the heat transfer coefficient changes with the local fluid temperature. Influence of different experimental parameters on heat transfer was also concluded. Results indicate that heat transfer of kerosene under supercritical pressure is mainly determined by its physical properties and the flow state. The heat transfer characteristics of kerosene under supercritical pressures could be divided into three regimes, namely the common heat transfer regime, the enhanced heat transfer regime and the deteriorated heat transfer regime. Heat transfer enhancement is due to the combination of turbulent mixing and the drastic change of properties of kerosene near pseudo-critical temperature in the near wall zone while heat transfer deterioration is caused by the "pseudo-film boling" of the high temperature fluid in the near wall region. |
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