Supersonic swirling separation plays an important role in the separation of the water vapor and heavy hydrocarbons in natural gas processing. A viscous flow solver with slip model was developed to predict the non-equilibrium condensation phenomenon in supersonic separator. Several sets of experiments were conducted to validate the accuracy of numerical models. The detailed introduction of the experimental device was discussed. Then, to investigate the behavior of gas-droplet two-phase flow with strong swirls, the tangential velocity and centrifugal acceleration were simulated. Moreover, the distributions of droplet number density and bulk density of dispersed droplet phase in the supersonic separator were discussed in detail.