Thermal Influence on Flow Behaviour and Turbulence in a NASA C3X Nozzle Guide Vane: A CFD Investigation

Abstract

Gas turbines remain central to modern power generation and aviation, where even minor aerodynamic improvements can cut fuel consumption and lower emissions. The present study analyses the impact of varying mainstream temperature on flow dynamics and turbulence inside a NASA C3X nozzle guide vane (NGV) through high-resolution CFD modelling. Previous work has primarily addressed wake development with nearly constant inlet temperature, but limited attention has been paid to the role of temperature-related variations in density and viscosity in controlling TKE, turbulence Reynolds number, static pressure, and velocity distributions. A three-dimensional steady-state CFD model was built and meshed using the Fluent Meshing Watertight Geometry workflow. The numerical setup used the pressure-based solver of ANSYS Fluent 2024 R1 together with the SST k–ω turbulence model to resolve boundary-layer behaviour and wake structures with high fidelity. The inlet pressure was kept fixed, and the mainstream temperature was gradually adjusted from 600 K to 1500 K to isolate thermal influences on the flow. The results show that increasing mainstream temperature lowers air density and raises viscosity, which dampens small-scale turbulence, reduces the turbulent Reynolds number, and alters static-pressure contours. Conversely, lower temperatures enhance mixing and increase TKE. The computed static-pressure field was qualitatively checked against published results for comparable vane geometry, supporting the physical credibility of the numerical predictions. By showing that temperature changes alone can reorganize turbulence and pressure behaviour, this work contributes essential understanding for the development of next-generation nozzle-guide-vane cooling techniques and high-efficiency turbine stages, which in turn can enhance cycle efficiency and help cut environmental impacts.