基于超音速两相膨胀的新型CO_(2)制冷循环研究

Study on the novel CO_(2) refrigeration cycle based on supersonic two-phase expansion

提出了一种基于超音速两相膨胀的新型CO_(2)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CO_(2)制冷循环COP较现有性能相对最优的CO_(2)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C_(2)H_(2)和N;后制冷温度更低,加入C_(2)H_(2)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C_(2)H_(2)时,可获得最大相对卡诺效率为0.93,较单一CO_(2)的相对卡诺效率提高了26%,而加入N;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CO_(2)制冷循环具有较好的原理可行性,为CO_(2)有效利用、人工合成制冷剂替代、CO_(2)高效制冷提供一种可能的参考。

A novel CO_(2)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 CO_(2)refrigeration cycle is improved by 63.2%compared with the existing COP of the CO_(2)transcritical refrigeration cycle with relatively optimal performance,and the operating pressure of the system is greatly reduced.Adding C_(2)H_(2)and N;can lower the cooling temperature.Adding C_(2)H_(2)can improve the relative Carnot efficiency,and the effect becomes more significant with the increase of the addition amount.When adding 30%C_(2)H_(2),the maximum relative Carnot efficiency can be obtained as 0.93,which is 26%higher than the relative Carnot efficiency of CO_(2)alone.Adding N;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 CO_(2)refrigeration cycle has good feasibility,which provides a possible reference for the effective utilization of CO_(2),the substitution of synthetic refrigerant and the efficient refrigeration of CO_(2).