【摘要】 提出了一种基于超音速两相膨胀的新型CO₂制冷循环,开展热力学分析和模拟计算。结果显示:在空调温区工况,新型CO₂制冷循环COP较现有性能相对最优的CO₂跨临界制冷循环COP提升了63.2%,且系统运行高压大大降低;自然工质气体添加剂对循环性能有较大影响,加入C₂H₆和N₂后制冷温度更低,加入C₂H₆可提高相对卡诺效率,且随加入量的增加,效果越显著,当加入30%的C₂H₆时,可获得最大相对卡诺效率为0.93,较单一CO₂的相对卡诺效率提高了26%,而加入N₂则降低相对卡诺效率;超音速两相膨胀机入口压力、入口温度和旋流分离段出口压力均对循环性能有较大影响,可调节以上参数提升循环制冷表现。研究表明:新型CO₂制冷循环具有较好的原理可行性,为CO₂有效利用、人工合成制冷剂替代、CO₂高效制冷提供一种可能的参考。更多还原

【Abstract】 A novel CO₂ refrigeration cycle based on a supersonic two-phase expander（STPE） was proposed, and the thermodynamic analysis and simulation were carried out. The results show that the COP of the novel CO₂ refrigeration cycle is improved by 63.2% compared with the existing COP of the CO₂ transcritical refrigeration cycle with relatively optimal performance, and the operating pressure of the system is greatly reduced. Adding C₂H₆ and N₂ can lower the cooling temperature. Adding C₂H₆ can improve the relative Carnot efficiency, and the effect becomes more significant with the increase of the addition amount. When adding 30% C₂H₆, the maximum relative Carnot efficiency can be obtained as 0.93, which is 26% higher than the relative Carnot efficiency of CO₂ alone. Adding N₂ decreases the relative Carnot efficiency. The inlet pressure, inlet temperature and outlet pressure of the cyclone separation section of the supersonic two-phase expander all have a great influence on the cycle performance, and the above parameters can be adjusted to improve the performance of the cycle refrigeration. The study shows that the novel CO₂ refrigeration cycle has good feasibility, which provides a possible reference for the effective utilization of CO₂, the substitution of synthetic refrigerant and the efficient refrigeration of CO₂.更多还原