✓ CAD model of the D250-TFLH2 configuration in CATIA parameterized and tested.
✓ Automated mesh generation of CAD model with Centaur established.
✓ Process chain for subsequent aerodynamic analysis of geometry variations employing FlowSim / Tau available on HPC cluster CARA
A double-pulse test (DPT) was implemented in the circuit simulation software LTSpice for the simulative testing of SiC semiconductor modules. A DPT is a standardised method for evaluating the transient switching processes of power semiconductors. By analysing the transient switching characteristics, the simulation provides a more detailed understanding of the switches used in power converters. The simulation thus provides insights beyond idealised datasheet parameters by taking into account parasitic effects and the behaviour of the gate driver.
First loop of the impact assessment framework has been fulfilled. Using the new aircraft models from HAP2 and implementing them into flight schedules in for setting up emission inventories, economic and ecologic LCA results and climate results. Flight schedules are retrieved from the analysis using FoAM_Dynamic based on the Scheduler output. Based on the schedule the vehicles were implemented using stepwise trajectories from the vehicle design to calculate the emission inventories for single flight but also global inventories. These inventories are forwarded to the climate assessment using AirClim and the global temperature response is modeled until 2070 for the global fleet and single flight events. Using LYFE and ecoLYFE economic and ecological LCA results then complete the first loop of the impact assessment in HAP6.
The purpose of this milestone is to define a suitable low-temperature PEM fuel cell system design for the Mild-Hybrid (MHEP) aircraft concept. An existing software tool for the design and optimization of PEM fuel cell systems for regional aircraft was modified to work for larger electrical power outputs and increased flight altitudes.
Based on a literature study, a literature-based overview of established, experimental and conceptual cooling methods for electrical machines was compiled. The following cooling concepts were identified for the main components that generate heat loss – stator iron core, stator windings and rotor iron core: Circulation/flow-through cooling, jacket cooling, annular gap cooling, flood cooling, cooling channel cooling, heat pipe cooling, waveguide cooling, spray/jet impingement cooling/jet impingement cooling, cooling by filling/pouring, insertion cooling, immersion cooling and hollow wave cooling. For the purpose of classifying, contextualising and categorising the extracted cooling approaches, a classification was made according to physical operating principles (e.g. auxiliary energy input, proximity of heat source and heat sink, type of heat dissipated, heat transfer mechanism) as well as by spatial localisation (e.g. assembly, assigned heat source, cooled component) of the concepts. Both classification methods were combined in a central overview.
A methodology for weighted evaluation of the cooling methods was then developed using pairwise comparison of evaluation criteria – cooling effectiveness, energy efficiency, additional weight, safety & reliability, cost & lifetime – and applied to the concepts. The highest potentials in terms of suitability for aviation applications were shown for the active approaches of cooling channel cooling and waveguide cooling or, in the case of passive cooling, for heat pipe cooling.
The results of the study at the end of the EXACT2 milestone MS 4.6.6 were presented and published at the German Aerospace Congress (DLRK) 2024 under the title “Overview and Weighted Evaluation of Cooling Concepts for High-Power Electric Machines in Electrified Aircraft Propulsion Systems” (F. Heise, S. Kazula).
Overview of the SotA written in form of a paper for a conference
Battery sizing tool ready, updated battery data and works with CPACS interface.
The purpose of the first loop is to test the interfaces, identify information gaps and other open points. A first way of work was established to retrieve an executable RCE workflow from an architecture definition for the three aircraft concepts (MHEP TF/TP and PHEP). For the first loop, the architectures were simplified and disciplines were clustered (e.g. lumped OBS systems). The current workflow can only handle a linear downstream sizing without feedback loops. This is currently under development in close collaboration with HAP1. The CPACS files were updated with preliminary results from the systems workflow.
The FSMDAO API for unified FlowSimulator plug-in access has been designed as a basis for future implementations required for EXACT-2 high-fidelity MDAO. The API for the required linear operators in CODA has been conceptualized.
The milestone has been completed. Various concepts for thermal management systems were investigated, with the focus on identifying promising multiphase cooling methods for heat exchanger channels. Two concepts were selected for further investigation: Spray cooling and film cooling. Within spray cooling, evaporative cooling, droplet cooling and spray impingement cooling modes are considered. Currently, the above concepts are being analyzed by numerical simulations to quantify their performance.
A comprehensive qualitative analysis has been conducted to identify sources of electromagnetic interference (EMI) in electrified aircraft applications across components, systems, and on the aircraft level. Detailed tables outlining causes and characteristics of potential EMI emitted by components of electrified aircraft propulsion system, along with their potential interaction with other system within the electrified aircraft has been developed. Furthermore, a comparative study of the drive train components from an EMC perspective have been developed.
Relevant tools are ready to be integrated. An exemplary workflow that contains most of the tools could be run in RCE using a custom CPACS schema from EXACT1. The communication with the new CPACS schema is currently under development and functionality will be distributed to the tool developers.
The interfaces of the preliminary design configuration data required for flight mechanics analyses have been identified. Flight mechanics evaluation software has been adapted to the CPACS interface for the relevant parameters.
First test versions of the EXACT2 aircraft models for testing. The Short-Medium-Range concepts from EXACT have been incrementally improved. The Mid- and Long Range concepts and references have been initialized. For the Liqud Hydrogen propelled Mid- and Long Range aircraft, a configuration with fuel tanks in the front and back is introduced. The cockpit is mounted on top of the fuselage to provide sufficient forward visibility.
The interfaces of all project disciplines have been identified and CPACS development requirements have been documented. An EXACT2-specific CPACS version has been initiated.
Initial version of energy carrier cost scenarios. Based on existing literature, various cost scenarios are compiled for the three energy carriers relevant in this project, renewable electricity, liquified hydrogen (LH2) and synthetic sustainable aviation fuel (SAF) derived from Power-to-Liquid processes. Various costs and scenarios are provided for different world regions, assuming certification criteria for the generation of green hydrogen which are in line with current regulations of the EU.
Overview of the inputs/outputs of all tools available or to be developed are identified, and their interaction within and between the individual HAPs is presented in a XDSM (eXtended Design Structure Matrix) workflow
Research into socio-economic and technological scenarios has been completed. A scenario workshop was held on 7 March to present the current status (post-EXACT1) and to define common ideas and parameters for scenarios. The results of research were presented and discussed. A global airport-to-airport demand forecast was created; this includes passenger numbers, frequencies and average aircraft sizes on routes, taking capacity on routes, taking into account capacity bottlenecks. Socio- economic scenario definitions have been incorporated here. Fleet concept and fleet production windows were defined. Two different technological scenarios are depicted here, focussing on a) SAF and b) hydrogen.