Analysis of the shroud leakage flow and mainflow interactions in high-pressure turbines using an unsteady computational fluid dynamics approach

Abstract: Endwall leakage flows interaction in shrouded high-pressure steam turbines is investigated to provide insights about loss and performances. The prediction of flow through the seal and the understanding of the leakage jet interaction with the main flow is performed using computational fluid dynamics (CFD). A modern research solver is used coupling the labyrinth and the main vane flows including most of the relevant geometric and aerodynamic features.Two similar shroud configurations are here analysed for two high-pressure turbine configurations. Each configuration refers to a different blade technology commonly used by Ansaldo Energia. The computational algorithm is based on a numerical solver developed and applied to solve the compressible Navier–Stokes equations in a multi-rows unsteady environment. The problem has been approached modelling the unsteady 1.5-stage interaction. The CFD results are commented addressing the potential source of losses.