A nitrogen (N₂) Brayton cycle is considered as an alternative to the conventional steam Rankine cycle to overcome essential risk during pressure boundary rupture accidents with sodium-water reaction in a steam-generator of a sodium-cooled fast reactor (SFR). The objectives of this study are to estimate the turbine performances after proposing three-dimensional (3-D) blade designs and to suggest an option of detailed turbine design for N₂ Brayton cycle-SFR applications. A free-vortex design method was applied in the 3-D design. Three candidates, including two- and three-stage designs, were selected from the Smith charts. Aerodynamic losses were investigated and compared through computational fluid dynamics analyses for the cases selected above. According to the results, rotor blade with milder curvature increased proportions of secondary and tip leakage losses among the total aerodynamic loss. When comprehensively considering the turbomachinery size and cycle thermal efficiency, the size of the two-stage turbine could be reduced to under 55% of the three-stage turbine size, resulting in no significant decrement of the cycle efficiency.

氮 (N ₂ ) 布雷顿循环被认为是传统蒸汽朗肯循环的替代方案，以克服钠冷快堆 (SFR) 蒸汽发生器中钠-水反应发生压力边界破裂事故期间的基本风险。本研究的目的是在提出三维 (3-D) 叶片设计后评估涡轮机性能，并建议对 N ₂进行详细的涡轮机设计选项布雷顿循环-SFR 应用。在 3-D 设计中应用了自由涡流设计方法。从史密斯圆图中选出了三个候选者，包括两阶段和三阶段设计。通过对以上选择的情况的计算流体动力学分析来研究和比较空气动力损失。根据结果​​，曲率较小的转子叶片增加了总空气动力损失中二次泄漏和叶尖泄漏损失的比例。综合考虑汽轮机尺寸和循环热效率，两级汽轮机的尺寸可以缩小到三级汽轮机尺寸的55%以下，循环效率没有明显下降。