WP 4: COMPONENTS MODELS DEVELOPMENT
This work package focuses on developing accurate, robust, and low time consuming models for the large variety of thermal and electrical components present in ECS architectures. In general, the approach for model most of the components has been based on achieving the best compromise between calculation speed and accuracy but also on guaranteeing the proper use at the system level.
The models that have been developed within the thermal framework include turbomachinery (reciprocating/centrifugal compressors, pumps and turbines), a wide spectrum of heat exchangers (enabling heat exchange between different types of fluids but also considering complex phenomena, namely, evaporation, condensation, and moist air), and several additional components such as valves, connecting tubes, sensors and reservoirs.
The main efforts have been oriented towards heat exchangers as their modelling has been particularly challenging due to several aspects. All the heat exchangers developed within the MALET project share a common structure configuration that allows to easily interchange fluid lines (e.g. an air-to-air heat exchanger can be easily turned into a air-to-refrigerant one). Internal pressure drop calculations have been included in all cases. Moist air evaporation and/or condensation has been also addressed. A switching moving boundary approach (SMB) has been implemented to take into account the flow regimes experienced by the refrigerant throughout evaporators and condensers. A calibration procedure for heat exchangers based on reference data provided by the Topic manager has been successfully developed and tested.
(SMB approach. Left: evaporator operating modes and transitions, right: transitions sturdiness test)
(liquid-to-moist air heat exchanger calibration. Left: heat ratio -reference vs. model-, right: corrector factors)
The models that have been developed within the electrical framework are the Electrical Machine, Inverter and ATRU models. Two references frames (ABC and DQ) have been considered both of which have multiple levels of complexity.
The DQ domain models have been developed in order to provide the user with Electrical Drive System modelling capabilities that require significantly less simulation time than their ABC equivalents. These models can be integrated with the MALET thermal system models so that the user can simulate large thermal systems, with long time dynamics, in significantly reduced time scales.
Overall guidance would be to: Use the DQ domain components when fast simulation of a large thermal or electrical system based on electrical machine drives (inverter and machine) is required. Use the ABC domain components to verify DQ models, for detailed electrical analysis or small scale thermal analysis, or when the load is passive components such as resistive or inductive loads.
(Electric components examples: motor)