核动力船舰超临界二氧化碳循环系统建模与性能分析

Modeling and performance analysis on supercritical CO2 power cycle in nuclear-powered vessels

为探究以超临界二氧化碳(supercritical carbon dioxide, S-CO2)布雷顿循环耦合核反应堆所构成的新型船舰动力装置的系统性能,选取4种高效紧凑的S-CO2循环(再压缩、内冷、部分冷却及再热)耦合4种典型船用核反应堆(铅冷快堆、高温气冷快堆、钠冷快堆及压水堆),构建了16种核动力船舰S-CO2循环动力系统及其热力学模型,研究分流比、透平入口压力、压缩机入口压力和循环最低温度对循环效率的影响.结果表明:存在最佳分流比及压缩机入口压力使循环效率达到最高;各系统循环效率随透平入口压力的提高,呈先迅速增长后趋于稳定趋势;S-CO2再热循环应用于上述4种典型船用核反应堆二回路系统时效率最高,分别为46.6%、50.8%、 44.5%及32.5%;根据高温气冷快堆S-CO2再热循环系统热力性能最佳,提出了其整体系统布置方案.

To investigate the system performance of a novel marine propulsion system consisting of supercritical carbon dioxide(S-CO2) Brayton cycle coupled marine nuclear reactor, four efficient and compact layouts of S-CO2 cycle(with recompression, inter-cooling, partial-cooling and reheating, respectively) were selected and integrated with four representative marine nuclear reactors, including a lead-cooled fast reactor(LFR), a high temperature gas-cooled reactor(HTGR), a sodium-cooled fast reactor(SFR), and a pressurized water reactor(PWR). 16 groups of systems and their thermodynamics models were established, and the effects of split ratio, turbine inlet pressure, compressor inlet pressure, and cycle minimal temperature on the cycle efficiency were studied. The results show that there is an optimum value of the split ratio and the compressor inlet pressure maximizing the cycle efficiency. With the increase of the turbine inlet pressure, the cycle efficiency of each system increases rapidly and then tends to be stable. The S-CO2 reheating cycle has the highest cycle efficiency when applied to the secondary loop system of each nuclear propulsion system, it is 46.6%, 50.8%, 44.5% and 32.5%, respectively. The performance of the integrated system of reheating cycle with HTGR is the best, thus its optimum arrangement plan is proposed.