Steam ejectors are vital components of ejector refrigeration systems and have attracted considerable attention owing to their energy savings and environmental protection. In this study, steam ejector models were optimized, validated, and compared by considering the three-dimensional and non-equilibrium condensation effects. The simulation results of the optimization model were compared with those of the ideal gas model. Based on the condensation model, the effects of the turbulence models (Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation methods (LES)) on the simulation results were studied. Complex flow phenomena captured by different models, such as shock waves, non-equilibrium condensation, and boundary layer separation, were compared and analyzed. The results show that the optimized steam ejector model can credibly predict the ejector performance and capture the complex flow phenomena inside the ejector at the lowest computational cost. The maximum liquid mass fraction obtained using the large eddy simulation method is lower than that obtained using the Reynolds-averaged Navier-Stokes method. The maximum relative deviation against experiments of the entrainment ratio was obtained using the large eddy simulation method of 11%. The condensation model reduces the average relative deviations of the entrainment ratio and critical discharge pressure by 72.0% and 29.9%, respectively.