The impact of propulsive architecture on the design of a 19-passenger hybrid-electric aircraft

Abstract

The electrification of aircraft is an on-going endeavor, currently examined intensively in the general aviation class. However, for the commuter class, the proper selection of the hybrid-electric propulsive architecture is instrumental, to fully exploit the electrification benefit. Within this work, a comparison of two 19-seater aircraft with different hybrid-electric propulsive components is made, using an in-house aircraft conceptual design tool. The first aircraft is based on a twin-turboprop parallel-hybrid configuration that cruises at low Mach number speeds and altitude. On the other hand, the second aircraft variant is based on a tri-fan series/parallel-hybrid configuration with an aft Boundary Layer Ingestion system that operates at both higher altitude and Mach numbers. A design space exploration is performed where different degrees of hybridization and batteries specific energy are considered, to define the technological requirements for each architecture. The evaluation of the propulsive architectures is based on block fuel reduction, overall mission duration, direct operating costs and total environmental impact. The results aim to quantify the benefits of each configuration and determine the one with the closest entry into service. Finally, it is observed that the overall environmental impact reduces by 26 % and 17 % for the turboprop and turbofan variants respectively.

Environmental and techno-economic evaluation for hybrid-electric propulsion architectures

“…9. Additionally, the kerosene production impact is reduced significantly, compared to the findings in a previous work [10]; however, this reduction is explained by the variation of certain coefficients in the ReCiPe update from 2008 to 2016, where the importance of kerosene production is reduced, compared to 2008.…”

“…Considering DOC, there are several methodologies to assess the economic feasibility of propulsive units [13-15], but there is a lack of assessment for smaller aircraft categories, such as the commuter aircraft (19-seater), especially if novel propulsive architectures are considered. Moreover, for the aircraft environmental impact evaluation, previous works indicated that the main contributor to the LCA is aircraft operation [10,15]. However, aircraft electrification brings new challenges and raises new research questions about the subject [16].…”

Multidisciplinary conceptual design for a hybrid-electric commuter aircraft

“…For aviation fuel, 3.16 kg of are emitted per kg of fuel burnt [1]. In the work of Nasoulis et al [51] the environmental impact of both conventional and hybrid-electric aircraft with different propulsion configurations (i.e., turbofan and turboprop variants) is examined, considering a life cycle analysis for aircraft conceptual design. Additionally, both EU electricity mix and power from renewable sources are considered in the environmental impact single score assessment.…”

The Enabling Technologies for a Quasi-Zero Emissions Commuter Aircraft

“…Results from an experiment performed at TU Delft [84] on different architectures show a net force benefit with respect to the free-stream case of about 9% for wake ingestion-i.e., propeller detached from the body, in its wake-and 18% for BLI-i.e., propeller installed on the body stern-with a propeller efficiency improvement of 11% for wake ingestion and of 21% for the BLI configuration, at J = 1. Other works also concluded that BLI can bring sensible to significant emissions reduction [85,86], also on commuter aircraft [87].…”