C.K. Sain, S. Kazula, L. Enghardt

This paper describes possible topologies for electric propulsion systems in a regional aircraft; identifies major critical components and challenges concerning their feasibility; and presents a comparison between them. The existing electrified propulsion system topologies can be categorized into all-electric, turbo-electric, and hybrid-electric. These propulsion system topologies are briefly described along with few feasibility studies and examples. Subsequently, key challenges for the electric propulsion system are discussed, focusing on the attributes for low emission, high performance, less complexity and high reliability. This is followed by a detailed explanation of the functions, challenges, and examples from latest developments for the key components. In the final chapter, advantages and challenges in terms of emission, complexity, technology, economic and policy for each topology are summarized. The topologies in the all-electric category are based on batteries and fuel cells for storing and generating the required electrical energy. Most of the electrical energy is supplied to the electric motors for thrust generation by rotating the propellers. Due to absence of a conventional combustion process, emission reduction goals can potentially be met. Battery and fuel cells are quite efficient at their cell level, but the specific energy density at the propulsion system level drops dramatically, when the necessary structural weight of, for example, their thermal and air management is added. As a result, specific energy density falls below the levels required to enable medium- and long-range flights with average carrying capacity. Additionally, fuel cell and battery systems face challenges in terms of performance, safety, cost, and certification; quick dynamic response; cold condition start; production and supply of hydrogen gas; and integration of large hydrogen gas tanks and battery system on-board of the aircraft. Turbo-electric topologies contain reliable gas turbine-driven electricity generators that offer a high level of safe and certified technology. However, with turbo-electric architectures, it seems difficult to achieve the targeted emission reductions without relying on sustainable and carbon-free aviation fuels from biomass and hydrogen. Direct combustion of hydrogen gas in the combustion chamber is currently at a low technological readiness level. Hybrid-electric topologies are composed of a combination of power generation units from gas turbine and from fuel cell and/or battery systems. They offer low-emission operation during long-range flight phases; and high safety, reliability, and required specific power through gas turbine-based turbo propulsion unit during takeoffs and climbs. This paper provides an overview of research and developments in electric propulsion technologies and serves as a foundation for future work on a fuel cell-based all-electric topology.

Deutscher Luft- und Raumfahrtkongress 2022, Dresden

Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn, 2023

Conference Paper

englisch

21,0 x 29,7 cm, 16 Seiten

urn:nbn:de:101:1-2023011312074226896269

10.25967/570151

Electric Aircraft Propulsion, Hybrid Electric Aircraft

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Sain, C.K.; Kazula, S.; Enghardt, L. (2023): Electric Propulsion for Regional Aircraft - Critical Components and Challenges. Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V.. (Text). https://doi.org/10.25967/570151. urn:nbn:de:101:1-2023011312074226896269.

13.01.2023