Refueling of LH2 Aircraft—Assessment of Turnaround Procedures and Aircraft Design Implication

Jonas Mangold, Daniel Silberhorn, Nicolas Moebs, Niclas Dzikus, Julian Hoelzen, Thomas Zill and Andreas Strohmayer
Additional contact information
Jonas Mangold: Institute of Aircraft Design, University of Stuttgart, 70569 Stuttgart, Germany
Daniel Silberhorn: Institute of System Architectures in Aeronautics, German Aerospace Center (DLR), 21129 Hamburg, Germany
Nicolas Moebs: Institute of Aircraft Design, University of Stuttgart, 70569 Stuttgart, Germany
Niclas Dzikus: Institute of System Architectures in Aeronautics, German Aerospace Center (DLR), 21129 Hamburg, Germany
Julian Hoelzen: Institute of Electric Power Systems, Leibniz University Hanover, 30167 Hanover, Germany
Thomas Zill: Institute of System Architectures in Aeronautics, German Aerospace Center (DLR), 21129 Hamburg, Germany
Andreas Strohmayer: Institute of Aircraft Design, University of Stuttgart, 70569 Stuttgart, Germany

Energies, 2022, vol. 15, issue 7, 1-41

Abstract: Green liquid hydrogen (LH2) could play an essential role as a zero-carbon aircraft fuel to reach long-term sustainable aviation. Excluding challenges such as electrolysis, transportation and use of renewable energy in setting up hydrogen (H 2 ) fuel infrastructure, this paper investigates the interface between refueling systems and aircraft, and the impacts on fuel distribution at the airport. Furthermore, it provides an overview of key technology design decisions for LH2 refueling procedures and their effects on the turnaround times as well as on aircraft design. Based on a comparison to Jet A-1 refueling, new LH2 refueling procedures are described and evaluated. Process steps under consideration are connecting/disconnecting, purging, chill-down, and refueling. The actual refueling flow of LH2 is limited to a simplified Reynolds term of v · d = 2.35 m 2 /s. A mass flow rate of 20 kg/s is reached with an inner hose diameter of 152.4 mm. The previous and subsequent processes (without refueling) require 9 min with purging and 6 min without purging. For the assessment of impacts on LH2 aircraft operation, process changes on the level of ground support equipment are compared to current procedures with Jet A-1. The technical challenges at the airport for refueling trucks as well as pipeline systems and dispensers are presented. In addition to the technological solutions, explosion protection as applicable safety regulations are analyzed, and the overall refueling process is validated. The thermodynamic properties of LH2 as a real, compressible fluid are considered to derive implications for airport-side infrastructure. The advantages and disadvantages of a subcooled liquid are evaluated, and cost impacts are elaborated. Behind the airport storage tank, LH2 must be cooled to at least 19K to prevent two-phase phenomena and a mass flow reduction during distribution. Implications on LH2 aircraft design are investigated by understanding the thermodynamic properties, including calculation methods for the aircraft tank volume, and problems such as cavitation and two-phase flows. In conclusion, the work presented shows that LH2 refueling procedure is feasible, compliant with the applicable explosion protection standards and hence does not impact the turnaround procedure. A turnaround time comparison shows that refueling with LH2 in most cases takes less time than with Jet A-1. The turnaround at the airport can be performed by a fuel truck or a pipeline dispenser system without generating direct losses, i.e., venting to the atmosphere.

Keywords: liquid hydrogen; refueling; refuelling; hydrogen aviation; hydrogen fuel supply; aircraft design; sustainable aviation (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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