The purpose of this paper is to verify the impact ofDiscrete-ordinates method (DOM) radiation model and conformal mesh (shared topology) on simulation accuracy of HVCB short-circuit current, and the pressure of the thermal expansion chamber is used to be the comparative index. PTFE vapor is the energy transfer medium between the arc and the filled gas, the absorption rate of arc energy by the PTFE nozzle has been one of the focuses of research. Compared with the method of exposure ratio, the introduced DOM radiation model makes calculations in this aspect more accurate; In computational fluid dynamics (CFD), the choice of meshing type can significantly impact the accuracy and efficiency of the simulations. Conformal mesh provides high accuracy in representing the geometry and in resolving boundary layers and interfaces. It ensures smooth transition of the solution variables across interfaces, which is beneficial for capturing gradients and discontinuities accurately. After the application of radiation model and conformal mesh, the updated method was applied to 6 models and compared with past simulation techniques. The results showed that the simulation results of thermal expansion chamber pressure had a significant improvement in accuracy.