Dry Low NOx (DLN) combustors are mainly adopted in heavy-duty gas turbines due to their ability to achieve low emissions through lean-premixed operation without requiring water or steam injection. This research focuses on a DLN1.0 with a can-annular architecture and a venturi-stabilised reaction zone. Its operability is limited by a “four-sided box” that balances NOx emissions, CO burnout, stability and dynamics. These features drive the development of reduced-order tools that accurately simulate the physical phenomena with low computational effort. This study develops a one-dimensional thermo-fluid model of a DLN1.0 combustor for power generation. Given the 3D model of the combustor, each component and subcomponent is represented by the geometry of the actual elements and the associated pressure losses.