为深入分析由燃气轮机循环和sCO2循环组成的联合循环的循环关键参数变化对系统的影响，建立了燃气轮机-sCO2联合循环的热力学模型和经济性模型。从热力学和经济性两个角度出发，对关键参数进行敏感性分析，深入探究联合循环系统中关键参数的变化（如高温sCO2透平入口温度、sCO2压缩机出口压力、sCO2压缩机入口温度、sCO2压缩机入口压力、sCO2循环流量和分流比）对部件和整体的热力学和经济性能的影响规律以及原因。并利用遗传算法对系统进行优化，优化目标是使?效率最高或平准化电力成本最低，以期为系统设计提供参考。结果表明：提高高温sCO2透平入口温度和sCO2循环流量、降低sCO2压缩机入口温度和分流比能够提高系统?效率；上述关键参数均存在一个最佳值使系统的平准化电力成本最低；当天然气价格为4 $/GJ时，优化后，系统净功率最高可达到463.4 MW，?效率最高可达到54.67%，单位装机容量投资成本最低可达到347.16 $/kW，平准化电力成本最低可达到35.92 $/(MW·h)。

To deeply analyze the influence of the changes of key parameters on the system of the combined cycle consisting of a gas turbine cycle and a sCO2 cycle, a thermodynamic model and an economic model of the combined cycle are established. From both thermodynamic and economic perspectives, sensitivity analyses of the key parameters are conducted to investigate in depth the effects of changes in the key parameters in the combined cycle system (e.g., high-temperature sCO2 turbine inlet temperature, sCO2 compressor outlet pressure, sCO2 compressor inlet temperature, sCO2 compressor inlet pressure, mass flow rate of the sCO2 cycle, and shunt ratio) on the patterns of the thermodynamic and economic performances of the components and the overall system and the causes. The system was also optimized using a genetic algorithm with the optimization objective of maximizing the exergy efficiency or minimizing the levelized cost of electricity, to provide a reference for the system design. The results show that: increasing the high-temperature sCO2 turbine inlet temperature and mass flow rate of the sCO2 cycle, and decreasing the sCO2 compressor inlet temperature and shunt ratio can improve the exergy efficiency of the system. there exists an optimal value of each of the above key parameters to make the system with the lowest levelized cost of electricity; when the price of natural gas is 4 $/GJ, after the optimization, the system's net power can reach a maximum of 463.4 MW, and the sCO2 efficiency can reach a maximum of 54.67%, and the unit installed power cost can reach a maximum of 1,000 MW. 54.67%, the lowest investment cost per unit of installed capacity can reach 347.16 $/kW, and the lowest levelized cost of electricity can reach 35.92 $/(MW·h).

TK115

国家自然科学基金项目（面上项目，重点项目，重大项目）