In order to study the sealing performance of supercritical carbon dioxide (S-CO2) dry gas seal,considering the actual gas effect,inertia effect and turbulence effect,a periodic geometric model of spiral groove computational domain was established by using Solidworks software.The model was imported into ICEM software for structured meshing,and the phase data of S-CO2 physical properties were obtained by using REFPROP software.The flow field of S-CO2 dry gas seal was simulated by compiling the obtained physical parameters into CFD program.The results show that the density and viscosity of S-CO2 in the dry gas seal are increased first and then decreased from outer radius to inner radius,and the temperature is decreased gradually from outer radius to inner radius.With the increase of the depth of the spiral groove,the opening force is first increased and then decreased,while the leakage id increased monotonously with the depth of the spiral groove.The groove depth has a larger influence on the leakage,but a smaller influence on the opening force.With the increase of rotating speed,the opening force and leakage of gas film are increased monotonously,while with the increase of film clearance,the opening force of gas film is decreased and the leakage is increased.Considering the sealing stability,the overall sealing performance of the studied S-CO2 dry gas seal is the best when the film thickness is 3.05 μm and the groove depth is 5.05 μm.