Abstract：Helium-xenon mixtures can be used as the cycle working fluid and reactor coolant for space nuclear reactor power (SNRP) systems using a closed Brayton cycle. The cycle designers must know how the components of the helium-xenon mixture affect the net system efficiency to choose the best working fluid. A thermodynamic model is developed with Fortran 95 for the SNRP Brayton cycle to analyze the net system efficiency for various molecular mass mixtures in terms of the adiabatic coefficient, regenerator effectiveness and normalized pressure loss coefficient. The results show that the adiabatic coefficient has little effect on the net system efficiency, while the net system efficiency increases with increasing regenerator effectiveness and decreases with increasing normalized pressure loss coefficient. The compressor and turbine in a space Brayton cycle are smaller with higher molecular mass helium-xenon mixtures, so He-8.6%Xe is chosen as the cycle working fluid with the maximum regenerator effectiveness. For cold and hot sink temperatures of 403 K and 1 300 K, the net system efficiency is 29.18%.
杨谢, 石磊. 空间核反应堆电源闭式Brayton循环热力学分析[J]. 清华大学学报（自然科学版）, 2018, 58(9): 821-826.
YANG Xie, SHI Lei. Thermodynamic analysis of closed Brayton cycles for space reactor power system. Journal of Tsinghua University(Science and Technology), 2018, 58(9): 821-826.
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