A Multi-Fluid Extension of a Gas Turbine Performance Model

Kurzfassung

Novel aero engine concepts or industrial applications introduce several new fluids, such as refrigerants for cooling of electric components, hydrogen as a fuel, or CO2 as working fluid. These and many other cycles and concepts incorporating various fluids have to be further analyzed during an early design stage. The DLR performance program (DLRp2) and most other gas turbine performance codes can only handle a single fluid model, a thermally perfect gas, and they cannot treat several fluid models simultaneously. Therefore, a detailed analysis of the aforementioned concepts is not possible using the standard fluid model. This paper derives the additional requirements for new fluid models extending the thermally perfect gas model, which have to be integrated into modern performance codes. This is based on a review of current and future design tasks in aero engine applications and in the ground-based energy sector. Using the requirements, Coolprop is chosen as a suitable fluid model and its integration into DLRp2 is presented and described in detail. Finally, the advantage of a joint analysis of multiple fluid cycles within one model is presented using a hydrogen conditioning system model for a gas turbine as demonstration case, while also quantifying the computational penalty of a more detailed fluid model.