This project was brought to light thanks to the collaboration between the Polytechnic of Turin and EthosEnergy S.p.A., a company that operates in the turbomachinery field through design, production, and maintenance of its components. The Thesis aims at the modelling and optimization of a gas turbine unit through the different AxSTREAM software solvers. The gas turbine in discussion goes with the name FR1625. AxSTREAM is a software platform for multidisciplinary design, analysis and optimization, provides an integrated and streamlined approach to turbomachinery design. There are different software belonging to AxSTREAM that can study the turbomachinery by various approaches. In the case of this thesis, AxSTREAM solver has been used to model both the compressor and the turbine, the cooling network instead was carried out by AxSTREAM NET.