Thermal–Fluid–Structure Interaction Analysis of the Impact of Structural Modifications on the Stress and Flow Parameters in a Nozzle Box Made of StE460 Steel

This study explores the impact of structural modifications on the stress distribution and flow characteristics of a nozzle box in a steam turbine, specifically targeting the components made from high-strength StE460 steel. Using Computational Fluid Dynamics (CFDs) and Thermal-Fluid-Structure Interaction (Thermal-FSI) simulations, we examine the effects of shortening the nozzle guide vanes by 7 mm. This novel approach significantly reduces the stress levels within the nozzle box segments, bringing them below the critical thresholds and thus enhancing component durability. Moreover, the modification leads to improved flow efficiency, evidenced by the higher outlet velocities, temperatures, and mass flow rates, all of which contribute to increased turbine power output without negatively impacting the downstream flow dynamics. This balance between durability and flow performance underscores the value of targeted structural innovations in high-temperature, high-stress environments. This study's findings suggest that such modifications can substantially improve turbine efficiency and operational longevity, marking an important advancement in industrial applications where reliability and efficiency are paramount. Future work will assess the long-term effects under variable operational conditions to further optimize these benefits.