Conjugate Heat Transfer Analysis of a Heavy-Duty Gas Turbine Blade Equipped with Rib-Turbulated Channels

Turbine cooling represents a critical challenge in gas turbine technology. The continuous demand for higher efficiency and power output requires increased turbine inlet temperatures, making effective cooling strategies essential to preserve the structural integrity and extend the service life of hot-section components. Internal and external cooling mechanisms are therefore employed. Part of the compressor air is routed through dedicated channels inside of the secondary air system that feeds the cooling channels, while the hot main flow interacts with the external surface. The combined effect of these processes governs the overall thermal performance of the turbine. Among the available techniques, rib-turbulated channels are widely adopted, as they enhance heat transfer by breaking the boundary layer, thus promoting turbulence. This mechanism strengthens the thermal interaction between coolant and blade material, enabling greater heat dissipation compared to smooth channels. This thesis presents a Conjugate Heat Transfer (CHT) analysis on a heavy-duty gas turbine blade provided by EthosEnergy Italia SPA. Simulations are conducted with the commercial CFD software ANSYS Fluent, which allows for coupling the evaluation of the thermal field and of the metal temperature, including internal and external flow. Two configurations are analysed: the original rib-turbulated geometry and a modified version with smooth channels. The objective is to compare local and overall distributions of the heat transfer coefficient and to assess the impact of ribs on cooling performance. The results indicate that the ribbed configuration achieves higher heat removal capability than the smooth design. The study provides a direct comparison between the two geometries and clarifies the influence of internal channel design on the thermal behaviour of heavy-duty gas turbines.