Highlights• CFD-based shape optimization of a nozzle and a turbine blade regarding nucleating steam flow is performed.• Nucleation rate and droplet radius are the best suited objective functions for the optimization p rocess.• Maximum 34% reduction in entropy generation rate is reported for turbine cascade.• A maximum 10% reduction in Baumann factor and a maximum 2.1% increase in efficiency is achieved for a turbine cascade. Abstract:In this study CFD-based shape optimization of a 3D nozzle and a 2D turbine blade cascade is undertaken in the presence of non-equilibrium condensation within the considered flow channels.A two-fluid formulation is used for the simulation of unsteady, turbulent, supersonic and compressible flow of wet steam accounting for relevant phase interaction between nucleated liquid droplets and continuous vapor phase. An in-house CFD code is developed to solve the governing equations of the two phase flow and was validated against available experimental