球床沸水堆燃料组件稳态换热数值模拟研究

以球床沸水堆（PBWR）燃料组件为研究对象,运用CFD商用软件FLUENT,采用多孔介质模型和欧拉两相流模型,燃料组件流动沸腾换热进行计算分析。分析额定工况下的燃料组件内稳态热工水力特性及孔隙率对计算结果的影响。计算结果表明：球床沸水堆燃料组件横截面的热工参数分布与传统压水堆的壁面加热管道相比具有新的特点,采取适当的燃料组件结构孔隙率,可获得较大堆芯换热效率及较小的堆芯压降。

Numerical Analysis on Thermal-Hydraulic Characteristics of the Fuel Assembly in Pebble Bed Water-cooled Reactor

The geometric model of the fuel assembly in Pebble Bed Water-cooled Reactor （PBWR） was established by the CFD code FLUENT. Using the user defined function, the forced nucleate boiling flow in the fuel assembly was studied by the porous media model and the Euler model. The steady thermal-hydraulic characteristics in fuel assembly and the effect of the porosity on the calculated results were analyzed. The calculation results show that the pressure loss and temperature difference of the PBWR are much larger than PWR using the tubular fuel elements. It is necessary to choose a suitable hole ratio to get a better heat- transfer efficiency and less de-pressure of the core.