针对远洋船舶节能减排和高效营运的需求，从提高船用低速柴油机总效率出发，对其烟气进行余热回收，搭建三种布置形式的超临界二氧化碳布雷顿循环。将实测的6EX340EF-UA型船用低速柴油机不同工况烟气参数作为输入，以系统总效率和净输出功为目标，对系统循环参数进行优化。结果表明，再压缩超临界二氧化碳布雷顿循环的烟气余热回收系统可实现总效率最大提升3.15%，最大净输出功率增加335 kW。通过再压缩超临界二氧化碳循环系统的㶲分析发现，烟气换热器的㶲损失最大，这为后续系统性能优化提供了依据。

Aiming at the needs of energy conservation, emission reduction and efficient operation of oceangoing vessels, by starting from improving the overall efficiency of marine lowspeed diesel engine, waste heat recovery of flue gas was carried out, and three layout forms of supercritical carbon dioxide Brayton cycle were built. Taking the measured flue gas parameters of 6EX340EFUA marine lowspeed diesel engine under different operating conditions as the input, and aiming at the total efficiency and net output power of the system, the cycle parameters of the system were optimized. The results show that the total efficiency of the flue gas waste heat recovery system with recompression supercritical carbon dioxide Brayton cycle can be increased by 3.15% and the maximum net output power can be increased by 335 kW. By the analysis of recompression supercritical carbon dioxide cycle system, it is found that the loss of flue gas heat exchanger is the largest, which provides a basis for subsequent system performance optimization.