This work presents the results of one- and two-dimensional numerical analysis of a choked capillary flow and the analysis of particle formation and growth in a capillary. The object of this study was to determine conditions of seed particle growth and homogeneous nucleation. The Lagrangian approach was used for the calculation of droplet growth, and vapor depletion and latent heat release were considered in the calculation of the two-dimensional flow field. Several parameters were derived from the analysis of the flow field and the growth rate of the droplet, and their effects are discussed. It was found that the viscous pressure loss during the expansion has a significant effect on both heterogeneous and homogeneous condensation. The difference in the results between one- and two-dimensional calculations is also discussed and conclusions are presented.