六边形组件棒束通道内液态铅铋流动传热特性实验研究

Experimental Study on Liquid Lead-bismuth Heat Transfer Characteristic in Rod Bundle Channel of Hexagonal Assembly

  • 摘要: 为探究液态铅铋在六边形组件棒束通道内流动传热特性,开展了操作压力为0~250 kPa、实验段入口温度为200~300 ℃、热流密度为0~47 071.48 W·m-2、质量流量为0~4 kg·s-1及Pe为300~600的液态铅铋流动传热实验。依据实验结果重点分析了液态铅铋在不同测点位置、热流密度和进口温度等工况下的棒束内通道传热特性。基于棒束通道流动传热特性实验数据,对国际上液态金属的流动传热经验关系式进行计算评估,并参考Mikityuk关系式的基础形式,拟合出一个新的流动传热经验关系式。采用德国卡尔斯鲁厄研究中心(KIT)的实验数据校核并评价该关系式的适用性和可信度。结果表明,拟合经验关系式对KIT棒束的计算相对偏差为±20%,证明新经验关系式有较高的适用性与可信度。该实验数据与经验关系式可为我国液态金属冷却快堆六边形组件棒束通道内流动传热特性的设计研究提供参考与技术支持。

     

    Abstract: To explore the flow and heat transfer characteristics of liquid lead-bismuth eutectic (LBE) in the hexagonal rod bundle assembly, an experiment on liquid lead-bismuth heat transfer was carried out at 0.250 kPa of operation pressure, 200-300 ℃ of inlet temperature, 0.47 071.48 W·m-2 of heat flux, 0.4 kg·s-1 of mass flow rate, and 300-600 of Peclet number (Pe). The experimental facilities and operating conditions were introduced in detail, and the uncertainty of this experiment was analyzed to ensure the accuracy of the results. The heat transfer characteristics of liquid lead-bismuth in the rod bundle under different measuring points, heat flux, and inlet temperature were analyzed, and the relevant experimental results were obtained. The simplified Reynolds averaging equation of turbulent flow and heat transfer were also introduced to analyze the characteristics of LBE based on experimental results. The experimental data show that different inlet temperatures have little effect on the flow and heat transfer characteristics of LBE. At high Pe operating condition, the difference of heat transfer of LBE under different wall heat fluxes is also not significant. Based on the experimental measurements of flow and heat transfer characteristics in the rod bundle channel, the flow and heat transfer empirical relations of liquid metal in the world were calculated and evaluated. The results show that the relation of Mikityuk has the best prediction to this experiment which is introduced in this article. This is because that Mikityuk sorts and analyzed the previous heat transfer relations for liquid metals, and obtains a new form to describe the heat transfer relations for liquid metals. Therefore, a new heat transfer relation of LBE was fitted with reference to the basic form of relation of Mikityuk. The applicability and reliability of the new empirical relation were checked out and evaluated by the experimental data of Karlsruhe Institute of Technology (KIT) in Germany under 19 rods bundle operating condition. The calculation results show that the deviation of the new empirical relation for the KIT 19 rod bundle is ±20%, which proves that the new empirical relation has the high applicability and reliability. Finally, based on the similarity principle of fluid mechanics, the reason for the deviation between the empirical relationship fitted in this article and the KIT 19 rod bundle experiment data was also analyzed. The experimental data and the new empirical relation in this article can provide the references and technical supports for the design and research of flow and heat transfer characteristics of LBE in rod bundle channel of hexagonal assembly in the liquid metal cooled reactor in China.

     

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