Conceptual Design of Air and Thermal Management in a Nacelle-Integrated Fuel Cell System for an Electric Regional Aircraft

Kurzfassung

The all-electric aircraft is seen as an enabler technology for low-emission regional aviation. Currently, the desired flight range and payload capacities are not achievable due to the high weight of a potential all-electric propulsion system, which can be based on a low-temperature polymer electrolyte membrane (LTPEM) fuel cell system (FCS). This paper presents the conceptual design of the key components of the air and thermal management of an LTPEM FCS. Requirements and functions are discussed from the aircraft level to the FCS level. A detailed description of the LTPEM FCS is provided and critical components are identified. Emphasis is placed on air and thermal management and conceptual designs within the nacelle are generated and discussed. By varying the size, number and location of heat exchangers, air intakes, filters and compressors, different design variants are explored. Relevant state-of-the-art technologies for these purposes are evaluated and selected. Types and sizes of the largest components such as heat exchangers are calculated. Initial aero-thermal results are obtained using CFD and a down-selection is made for the best-fit design. Two system integration configurations are generated and compared in terms of performance, complexity, cost, and safety. An annular configuration includes inclined heat exchangers in small air ducts, which provides sufficient volume and surface area for the heat exchangers but is complex in terms of integration and accessibility for engine maintenance. On the other hand, an axial configuration provides a less complex design for the heat exchangers but is expected to achieve a decreased performance in terms of heat transfer. The results from the conceptual design phase will be used in the following preliminary design phase, where detailed performance studies, structural analysis, and safety assessments will be performed.