Numerical simulation of wet steam transonic condensation flow in the last stage of a steam turbine

Abstract

PurposeThe purpose of this paper is to study the condensation flow of wet steam in the last stage of a steam turbine and to obtain the distribution of condensation parameters such as nucleation rate, Mach number and wetness.Design/methodology/approachBecause of the sensitivity of the condensation parameter distribution, a double fluid numerical model and a realizable k-ε-kd turbulence model were applied in this study, and the numerical solution for the non-equilibrium condensation flow is provided.FindingsThe simulation results are consistent with the experimental results of the Bakhtar test. The calculation results indicate that the degree of departure from saturation has a significant impact on the wet steam transonic condensation flow. When the inlet steam deviates from the saturation state, shock wave interference and vortex mixing also have a great influence on the distribution of water droplets.Originality/valueThe research results can provide reference for steam turbine wetness losses evaluation and flow passage structure optimization design.