This project is carried out through a collaboration between Polytechnic of Tu- rin and EthosEnergy S.P.A., a company specialized in turbomachinery desi- gn, production, and maintenance of turbomachinery components. The aim of this study is the development of a Digital Twin model of an existing Heavy- Duty gas turbine to predict performance at all operating points and to optimise operation. The final objective is achieved using AxSTREAM, which includes various tools to design, analyze, and optimise the turbomachine. The AxSLICE tool is used to import the 3D geometry of the blades in the main software to create the preliminary model of both the compressor and the tur- bine.