A pressure based Eulerian–Eulerian multi-phase model for non-equilibrium condensation in transonic steam flow

A model for homogeneous nucleation in high-speed transonic flow and applicable to the wet stages of a steam turbine is presented. The model, implemented within a full Navier–Stokes viscous flow solution procedure, employs a pressure based finite-volume/finite-element discretization of the governing equations of fluid motion. Eulerian multi-phase equations, governing both the vapor and liquid phases, are formulated utilizing Classical nucleation theory and the concept of droplet interfacial area density. For the mass conservation of liquid a scalar equation is derived which includes the dispersive motion of the droplets due to turbulent unsteadiness. The solution strategy applies implicit time integration with no constraints on the time-step. Convergence strategies with the highly non-linear homogeneous nucleation process are described. These equations are applied to predict the moisture distribution in low- and high-pressure steam flow in a Laval nozzle and 2D rotor-tip section of a stage turbine.