A Fuel Cell System Sizing Tool Based on Current Production Aircraft

Abstract

Electrification of aircraft is on track to be a future key design principal due to the increasing pressure on the aviation industry to significantly reduce harmful emissions by 2050 and the increased use of electrical equipment. This has led to an increased focus on the research and development of alternative power sources for aircraft, including fuel cells. These alternative power sources could either be used to provide propulsive power or as an Auxiliary Power Unit (APU). Previous studies have considered isolated design cases where a fuel cell system was tailored for their specific application. To accommodate for the large variation between aircraft, this study covers the design of an empirical model, which will be used to size a fuel cell system for any given aircraft based on basic design parameters. The model was constructed utilising aircraft categorisation, fuel cell sizing and balance of plant sub-models. Fifteen aircraft categories were defined based on the primary function and propulsion method of the aircraft. For each category, propulsive power and electrical generation requirements were calculated. Based on the results from categorisation and the flight envelope of the aircraft, fuel cell and balance of plant systems are defined. The total system mass and volume are given as outputs, along with polarisation and power curves for the fuel cell. This study finds that the model can accurately predict the electrical generation capability and propulsive requirements across the defined aircraft categories. In addition, the model can appropriately define key, high-level fuel cell parameters based on current Polymer Electrolyte Membrane (PEM) technology. Total fuel cell system mass and volume are calculated and shown to be reasonable for small aircraft. For larger aircraft with a Maximum Take-Off Weight (MTOW) greater than 50,000kg, current PEM technology is not able to match the gravimetric power density of existing APUs. IntroductionElectrification of aircraft is on track to be a key design principal in the future due to the increasing pressure on the whole aviation industry to significantly reduce harmful emissions by 2050 [1]. This has led to an increased focus on the research and development of alternative power sources for aircraft, including fuel cells. These alternative power sources could either be used to provide propulsive power or as an Auxiliary Power Unit (APU).Hydrogen fuel cells produce electricity through an exothermic electrochemical reaction between hydrogen and oxygen. This highly efficient reaction only produces heat and water as by-products [2]. Two Fuel Cell (FC) technologies currently being researched for use in aerospace applications are Solid Oxide Fuel Cells (SOFC) and Polymer Electrolyte Membrane (PEM) fuel cells. A key difference between these two technologies is their operating temperature. The significantly higher operating temperature of a SOFC (700-1,000°C) compared with 60-100°C for a PEM FC [3] allows it to reform light fossil fuels such as methane into hydrogen. Ho...

Fast Sizing Methodology and Assessment of Energy Storage Configuration on the Flight Time of a Multirotor Aerial Vehicle

“…Constraints are applied to the propeller geometry, specifically the diameter (D p ) and the pitch angle ϕ p . The optimized motor/propeller pair obtained from the optimization allows for checking the condition to avoid motor overheating, as stated in Equation (32). Subsequently, the maximum thrust T MP max generated by the optimized motor/propeller pair was computed using Equation (34).…”

“…However, in order to obtain a pair motor/propeller that can satisfy the take-off and cruise segment mission, the sizing methodology takes into consideration two constraints. The first one is related to the speed of rotation and the torque of the propeller reported in Equation (32). Through this constraint, the obtained motor/propeller pair is able to satisfy the cruise phase while avoiding motor overheating.…”

“…For the hydrogen tank, a type 4 tank was selected among the gaseous hydrogen tanks. Liquid hydrogen is 800 times less in volume and has a higher energy density than gaseous hydrogen, but it must be kept at a low temperature, which limits its use in HFC UAVs [31,32]. A regression model that estimates the hydrogen tank mass M tank (kg), based on the amount of hydrogen m H 2 (g) required for the flight mission, is established as shown in Figure 7d.…”

Advanced Sizing Methodology for a Multi-Mode eVTOL UAV Powered by a Hydrogen Fuel Cell and Battery

“…In addition, the generation of the HFC polarization curve and the HFC sizing technique based on it are well described. Thirkell and Chen proposed a sizing method for a wide range of HFC systems presented through the consideration of various types of components [8]. Thomas suggested a multidisciplinary modeling and design environment that does not contain the assumption of a fuel-cell UAV [9].…”

“…Since the PEMFC is a hydrogen fuel cell with high technological maturity and operated at a low temperature of 30-100 • C, it is suitable for application to UAVs [14]. Air cooling is used as a method to maintain the temperature of the PEMFC, being suitable for UAVs with a power of under 5 kW [8]. For the hydrogen tank, a Type 4 tank was selected among the gaseous hydrogen tanks.…”