回热型超临界二氧化碳布雷顿循环在燃气轮机余热回收利用领域具有较大的发展和应用潜力，对其开展性能分析与优化具有重要意义。文中应用有限时间热力学理论,建立了变温热源条件下存在有限温差传热、不可逆压缩、不可逆膨胀等不可逆因素的回热型超临界二氧化碳布雷顿循环模型,分析了工质质量流率、压缩机与透平效率、总热导率对循环效率与循环压比特性关系的影响，然后在总热导率一定的条件下以效率最大为目标，对加热器、冷却器和回热器的热导率分配比以及循环压比、工质质量流率进行优化。结果表明：在文中取值范围内，经优化后的效率可比初始设计点提高37.96%。文中还给出了不同工质质量流率下效率达到最大时所对应的设计参数。

It is of great significance to perform performance analysis and optimization of regenerative supercritical carbon dioxide (S-CO2) Brayton cycle because it has great development and application potential in the field of gas turbines waste heat recovery and utilization. In this paper, the theory of finite-time thermodynamics is used to establish a regenerative S-CO2 Brayton cycle model with various irreversible factors including the heat transfer with finite temperature difference, the irreversible compression and the irreversible expansion under the condition of variable-temperature heat source. Then, the influences of working fluids mass flow rate, turbine and compressor efficiencies, and total heat exchanger inventory on the characteristic relationship between the exergy efficiency and the cycle pressure ratio are analyzed. Finally, by choosing the maximum exergy efficiency at fixed total heat exchanger inventory as the optimization objective, the heat conductance distribution ratios of the heater, the cooler and rege-nerator, as well as the mass flow rate of the working fluid and the cycle pressure ratio, are optimized. The results show that, within the parameter value ranges chosen in this paper, the optimized exergy efficiency increases by 37.96%, as compared with the initial design value. The design parameters corresponding to the maximum exergy efficiencies at different working fluid mass flow rates are also given.