Technical & Applied Article

Conceptual estimation of the noise reduction potential of electrified aircraft engines^★

¹ German Aerospace Center (DLR), Institute of Electrified Aero Engines, Department Aeronautical Requirements and Environmental Impact, 03046 Cottbus, Germany
² German Aerospace Center (DLR), Institute of Propulsion Technology, Engine Acoustics Department, 10623 Berlin, Germany

^* Corresponding author: thomas.geyer@dlr.de

Received: 10 November 2022
Accepted: 28 March 2023

Abstract

The advent of electrified propulsion systems for civil aircraft promises not only notable reductions of CO₂ and NO_x emissions, but also of perceived noise. In an attempt to estimate the noise reduction potential of fully electric aircraft engines, the current study compares the noise generated by classical turboprop and turbofan engines with noise spectra calculated for electrified engines. The calculation is based on published far-field sound pressure level spectra at different noise certification points, which are then modified to account for the absence of combustion-related noise sources. In addition to the overall sound pressure level, changes to the effective perceived noise level are also taken into account. The results clearly show that the electrification of the engine alone will not lead to the notable noise reductions that are required in order to achieve the goals for future aviation set by the European Commission. Instead, continued research is necessary to further reduce noise sources that will continue to be present in novel electrified aircraft systems, such as fan noise and airframe noise.