High-fidelity large eddy simulation of transonic wet steam flows through a steam turbine cascade

• Accurate prediction of wet steam and turbulent flow relationships. • Simulations showed good agreement with experimental data. • Condensation shock accurately captured in LES. • Higher turbulent kinetic energy in wet conditions. • LES is a promising approach for steam turbine analysis. Dry steam condenses into water droplets during the low-pressure stage of steam turbines utilized for thermal power generation. This phase change significantly affects turbine performance. Although there have been many numerical studies on wet steam flow, most are based on the Reynolds averaged Navier-Stokes (RANS) analysis, which cannot capture the details of turbulent flows interacting with condensed water droplets. This study proposed a high-resolution and high-fidelity numerical method for the large eddy simulation (LES) of transonic wet steam flows with a nonequilibrium condensation model to clarify the causal relationship between nonequilibrium condensation and turbulent flow. The method was applied to transonic wet steam flows through a steam-turbine cascade channel, and the results were compared with those obtained experimentally and by RANS. The obtained results indicated that the method captured the laminar-turbulent transition in the boundary layer and detailed wake structures. The results were compared with those obtained under dry conditions. This comparison suggests that the LES is crucial for accurately predicting the causal relationship between nonequilibrium condensation and turbulent flow.