Session: 01-11 Electrified Propulsion and Novel Cycles I

Paper Number: 151607

Design of Fuel Cell Systems in Aviation – Part I: Modelling and Component Design 

The development of novel propulsion systems is essential to meet zero-emission targets in aviation. One promising approach is the electrification of aircraft engines using hydrogen-based polymer electrolyte membrane fuel cells (PEMFC). In addition to the fuel-cell stack, the propulsion system includes several subsystems, which significantly determine the mass and volume and thus the feasibility. A key system is the air supply that preconditions the air on the cathode side for efficient and reliable operation and consists of a compressor, heat exchanger, humidifier, turbine and electric motor. In particular, the required compressor work to pressurise the air has a decisive influence on the power requirement, efficiency, and mass of the overall system. Further, the compressor operating range influences the possible operating range and strategy of the fuel-cell system. Another decisive subsystem of PEMFC-aircraft is the thermal management to manage the heat dissipation of all heat sources in the fuel-cell system.

In this two-part paper, a design approach for the air-supply system and its subcomponents is presented. The objective is to apply the design method to a reference medium-range aircraft with different numbers of cathode air-supply systems, as this is an important decision point that influences both the design of the individual components of the cathode air-supply system and the aircraft design, and thus the performance over the entire flight mission.

The focus of this part I is to derive design points and boundary conditions on the basis of an overall system simulation, which can then be used for a detailed design of the subcomponents, such as turbo components and the thermal management system.

To specify the design boundary conditions in terms of compressor mass flow and pressure ratio, as well as waste heat and respective temperature levels, the thermodynamic cycle calculation model of the in-house software ASTOR (AircraftEngine Simulation for Transient Operation Research) is used. The performance of the PEMFC system is calculated for an entire flight mission. Thereby, critical operating points for all components as well as mission fuel mass and system mass can be identified.

Based on this, compressors and turbines are designed for the identified design points. For this, a workflow is created that consists of an automated design in Multall, meshing in Autogrid and 3D flow simulation in TRACE.

The thermal management system is designed for take-off conditions using a simulation and optimisation framework in the programming languages Modelica and Python. Subsequently, its performance, including feedback to the PEMFC power output, is assessed over the flight mission.

Presenting Author: Marcel Stoewer Institute of Turbomachinery and Fluid Dynamics

Presenting Author Biography: The author studied mechanical engineering at the Leibniz University Hannover from 2016 to 2022. He is currently a PhD student and working as research assistant at the Institute of Turbomachinery and Fluid Dynamics at Leibniz University Hannover. He is participating in the project "Design Space Evaluation of the Air-, Heat- and Power-Management of Fuel Cells for Aviation" (DEFCA) of the Cluster of Excellence "Sustainable and Energy Efficient Aviation" (SE²A).

Authors:

Marcel Stoewer Institute of Turbomachinery and Fluid Dynamics
Patrick Meyer Institute of Jet Propulsion and Turbomachinery
Marius Nozinski Institute of Thermodynamics
Sebastian Lück Institute of Jet Propulsion and Turbomachinery
Stephan Kabelac Institute of Thermodynamics
Jens Friedrichs Institute of Jet Propulsion and Turbomachinery
Jan Goeing Institute of Jet Propulsion and Turbomachinery
Dajan Mimic Institute of Turbomachinery and Fluid Dynamics