液态铅铋合金在绕丝燃料棒组件子通道间湍流交混数值模拟

液态铅铋合金（LBE）是第四代液态金属核反应堆候选冷却剂，由于LBE热物性具有一定的特殊性，亟待对LBE在燃料组件子通道中的流动与传热过程开展研究。本文对LBE在带绕丝燃料棒组件中湍流流动进行数值模拟与分析，将燃料棒壁面温度的数值模拟结果与响应的实验数据相比较，2者具有较高的吻合度，说明数学模型及数值结果具有较高的可靠性与准确性；使用湍流交混系数β表征LBE在不同子通道间、不同燃料棒间隙宽度与燃料棒直径比（S/D）结构下的湍流交混情况，结果表明，不同子通道间β波动程度具有差异性，β的大小与S/D呈负相关。基于不同S/D与雷诺数的计算结果，拟合出不同子通道间β关联式，为绕丝燃料棒三角形排列方式的燃料组件子通道分析程序开发提供交混模型。 

Experimental Study on Enhancement of Pool Boiling Critical HeatFlux on SA508 Carbon Steel with Cold Spray Coating

In this study, a coating technique known as “cold spray” was developed to form a micro-porous coating on the SA508 Gr3 carbon steel heater, which was the prototypical material for the reactor vessel. On the rotatable experimental bench, downward facing pool boiling CHF experiments using a plate test section under atmospheric pressure was performed to investigate the quenching curves on the CHF limits with and without cold-spray coatings at different inclination angles. Quantitative measurements showed that the local CHF values for the coated surface were consistently higher than the corresponding CHF values for the bare surface, and that the use of cold-spray coatings could enhance the local CHF limits for downward facing boiling by more than 25%. In addition, the micro-porous coatings were stable enough after many cycles of heating and cooling.