In today’s rapidly evolving industrial landscape, characterized by increasing demands for energy efficiency and environmental sustainability, the rising inlet temperatures of gas turbines pose significant challenges in their thermal design. This thesis, a collaboration between Politecnico Di Torino and EthosEnergy S.p.A., examines the performance of the cooling system within the first stage stator blades of industrial high-pressure gas turbines. Motivated by various design considerations, this study investigates two scenarios involving modifications in the height and position of the cooling insert. Computational fluid dynamics (CFD) simulations are conducted to analyze the influence of changed cooling insert heights on main parameters for the cooling system.