Session: 01-16 Whole Engine Performance and Novel Concepts

Paper Number: 125840

125840 - Optimization of a Battery Electric Hybrid Propulsion System for a Short Range Aircraft 

The ACARE Vision describes the objective of climate neutrality for aviation by 2050. New engine concepts are currently investigated to fulfill this goal. Hybrid electric architectures are discussed as one possible solution to further reduce CO2-emissions. Hybrid engines combine different energy types to deliver the necessary power for the propulsors. One option to propel an aircraft is to connect an electric drive train with a conventional gas turbine and propellers. Varying the degree of hybridization changes the design of the overall propulsion system configuration. As a result, the sizing operating point of the individual component depends on the degree of hybridization and is not generally identical for all other components.

For short missions and certain levels of hybridization, a hybrid electric propulsion system could have advantages in block energy. The range in which the benefits of a hybrid electric system can arise are specified using a simplified method. The engine designs are optimized and examined in this optimal range.

In this paper, a serial electric hybrid propulsion system with a technology level of an entry into service in 2035 is pre-designed, targeting a 70-seat regional aircraft with an average range of 400nm. The objective of the corresponding study is to identify which degree of hybridization leads to an optimal overall propulsion system for a reference mission.

With this approach the propulsion system can be optimized regarding a given figure of merit and tailored to the specific boundary conditions in design and off-design operating points. 

To model the complex interdependencies a new multipoint design methodology is introduced. Designing optimal matched components allows to find an overall optimum propulsion system. This methodology consists of a pre-design of the system components, an assessment of the whole reference mission and the search for the optimum propulsion system by ideal matching of the size of the components across arbitrary operating points. The system comprises of propulsors, electric motors, electrical systems, generators, batteries, thermal management systems, gas turbines and nacelles. The thermodynamics and aerodynamics, weights, nacelle geometries, drag, thermal management, emissions and operating costs are considered. This enables a multidisciplinary overall assessment.

The methodology is based on a new type of computational structure which is explained in detail together with the resulting optimum propulsion system.

Presenting Author: Jonas Schroeter Technical University of Munich

Presenting Author Biography: Jonas Schroeter studied mechanical and aerospace engineering at the University of Munich from 2014 to 2020. He then started his PhD at the Chair of Turbomachinery at the same university. Hybrid-electric aircraft engines are the focus of his research.

Authors:

Jonas Schroeter Technical University of Munich
Fabian Armbrüster MTU Aero Engines AG
Reinhold Schaber MTU Aero Engines AG
Volker Gümmer Chair of Turbomachinery and Flight Propulsion