With increasing turbine inlet temperatures in modern gas turbines, efficient internal cooling of stator vanes is critical to ensure structural integrity and thermal performance. This thesis focuses on the optimization of the internal cooling system of the NASA C3X turbine stator vane, originally investigated by Hylton et al. The objective is to enhance thermal uniformity and reduce peak metal temperatures by modifying the distribution and geometry of ten internal cooling channels. The study is carried out in two main phases. In the first phase, a high-fidelity 3D Conjugate Heat Transfer (CHT) simulation is conducted using ANSYS Fluent. A steady-state, pressure-based solver is used to solve the RANS and heat conduction equations, and three turbulence models (k–ω SST, k–kl–ω, y–Re⁰ SST) are tested.