【摘要】 当铅铋快堆发生蒸汽发生器传热管破裂（Steam Generator Tube Rupture,SGTR）事故后，一回路高温液态铅铋合金（Lead-Bismuth Eutectic,LBE）与二回路高压过冷水相互作用产生大量蒸汽，这些气泡在LBE的携带作用下可能进入堆芯，引起局部传热恶化和功率瞬变，严重影响反应堆的安全运行。掌握气泡在液态LBE中的运动特性及其动力学行为，开发适用于LBE中气泡迁移的曳力系数模型，是开展SGTR事故堆芯安全评估的基础。基于CLSVOF(Coupled Level-Set and Volume-Of-Fluid)方法建立了气泡在高温液态LBE中迁移运动的三维数值模型，通过分析气泡的运动轨迹、速度和粒径的变化规律，结合气泡受力平衡方程，获得了气泡曳力系数的模拟值。在此基础上，对比分析了现有曳力模型对LBE中气泡迁移的适用性，优选了最佳曳力系数模型并进行了进一步优化，优化后的模型对于液态LBE中气泡曳力系数的计算误差在15%之内。研究结果可为后续SGTR事故安全分析程序的开发提供理论支持。更多还原

【Abstract】 [Background] Steam generator tube rupture(SGTR) accidents in lead-bismuth cooled fast reactors result in the generation of numerous steam bubbles owing to the interaction of the high-temperature liquid lead-bismuth eutectic(LBE) from the primary circuit and high-pressure subcooled water of the secondary circuit. These steam bubbles carried by the LBE may enter the core, causing local heat transfer deterioration and a power transient,seriously affecting reactor safety. [Purpose] This study aims to elucidate the movement and dynamic behaviors of steam bubbles in liquid LBE and develop a drag coefficient model applicable to bubble migration in LBE for assessing the safety of the core during SGTR accidents. [Methods] Based on the coupled level-set and volume-offluid(CLSVOF) method, a three-dimensional numerical model for calculating the drag coefficient of steam bubbles in LBE was established to study their movement and dynamic behaviors. Firstly, the deformation, velocity, and trajectory characteristics of bubbles in LBE were analyzed, and their drag coefficients were estimated. Then, the simulated drag coefficient values were compared with those from existing models whilst the prediction performance of the model proposed by Tomiyama was superior to those of the others. Finally, Tomiyama’s drag model was optimized by introducing the We number, and its applicability was analyzed. [Results] Analysis results show that the errors of the existing drag coefficient models are large under the condition of bubble–LBE two-phase flow, and the calculation error of the optimized model for the bubble drag coefficient in LBE is within 15%. [Conclusions] The feasibility of drag calculation model optimized in this study is verified, demonstrating its suitability for calculating the drag coefficient of steam bubbles in LBE.更多还原