Natural refrigerants such as CO2 have become a research hotspot. Under high-pressure conditions

a large throttling loss becomes the primary reason for the low circulation efficiency of the CO2 refrigeration cycle. Therefore

reducing the throttling loss is an effective method to improve efficiency. This study proposes a supersonic two-phase expander with a Laval nozzle as the core component. A CO2 supersonic two-phase expansion refrigeration cycle model is established

and an ideal cycle thermodynamic analysis and simulation investigation are conducted. The results show that the inlet pressure and temperature of the supersonic two-phase expander and the outlet pressure of the cyclone separation section affect the cooling performance of the system. The coefficient of performance (COP) of the CO2 supersonic two-phase expansion refrigeration cycle is 6.69

which is 1.63 times that of the existing CO2 transcritical refrigeration cycle

with relatively optimal refrigeration performance. Additionally

the operating pressure of the system is considerably reduced. The loss of liquid-phase velocity during gas-liquid separation affects the refrigeration performance of the system. The COP of the system decreases from 9.56 to 6.01

and the relative Carnot efficiency decreases from 0.95 to 0.60; however

it still remains at a high level. The preliminary thermodynamic analysis and simulation show that the proposed CO2 supersonic two-phase expansion refrigeration cycle is feasible and exhibits good development prospects.