Digital Twin for simulation of Aircraft Thermal Management System architectures in TheMa4HERA

As part of an EU Clean Aviation project considering Thermal Management for Hybrid Electrical Regional Aircraft (TheMa4HERA), a digital twin of the overall Thermal Management System (TMS) is being developed. This digital twin shall 1) identify critical conditions and flight cases in advance of subsystem hardware tests and 2) virtually demonstrate the behavior of the Thermal Management System (TMS) on system level during complete flight missions. It is expected that this good understanding of the complete system leads to an early detection of eventual design problems, can help to develop a better system design and aid certification. In this paper a base model of the TMS is presented, which is set up using the object-oriented modelling language Modelica and the open-source ThermoFluid Stream (TFS) Library developed by the German Aerospace Center (DLR). The TFS Library is selected, as due to the final model size of the digital twin, a very robust numerical solution is needed. The TMS is thereby composed of: 1) compartment environmental control system, 2) battery and power electronics cooling system and 3) fuel cell cooling system. In addition, the digital twin includes models for the fuselage and blocks for environmental conditions, mission profiles, setpoints and controllers. Furthermore, the paper will focus on the design decisions made and special attention will be given to the interfaces and user-Interface. By means of two usecases, its usage in design process will be presented and simulation results and their benefit will be showcased. To be able to do a fast system assessment, the base model is able to simulate complete flight missions at varying environmental conditions in approximately 3 minutes. For future detailed investigations, the model is set up in such a way that the components are replaceable using standard interfaces. This allows progressively detailing the model in the future by replacing simple models focused on computational robustness by high fidelity models focused on accuracy delivered from partners within TheMa4HERA to support virtual verification and validation.