61629: Student Aerospace, Mechanical Engineering or similar (f/m/x) - Research on certification requirements for the integration of liquid hydrogen tanks into aircraft structures (CS23 / CS25)

In order to fulfill the ambitious goals in CO2 emission reduction new technical solutions are needed to break the global dependency on fossil fuels in the commercial aviation domain. One way to radically reduce C02 emissions would be the conversion of conventional propulsion system to a hydrogen based one. A fuel cell powering an electrically driven propeller as well as a hydrogen driven gas turbine are solution approaches currently investigated at several DLR sites. Both approaches require a safe integration of a robust hydrogen storage systems into the aircraft structure. This concerns in particular the challenge to store the hydrogen under liquified conditions (-253°C). Thus, new aircraft’s structural components must be designed and sized in order to withstand the thermal loads implied by this severe temperature conditions on top of the mechanical loads induced by common flight and ground loads. In this context new design solutions are developed at the Institute of Composite Structures and Adaptive Systems.

This student vacancy offers you the chance to gain first hand work experience regarding the development of tanks for the storage of liquid hydrogen (LH2) designed for an aeronautical application. Your student research paper, bachelor or master thesis will contribute to the research activities at DLR by focusing on certification requirements given for „Normal Category” aeroplanes (CS 23) and „Large” aeroplanes (CS 25).

The requirements for the certification of a civil aircraft are defined by so called certification specifications (CS) within the area of influence of the European jurisdiction. These CS were originally developed for the certification of aircrafts, which rely on conventional aviation fuels. Thus, it is necessary to examine for which parts the requirements given by the CS can be adopted, must be extended or changed for the safe integration of LH2 Tanks into an aircraft structure.

Simultaneously LH2 Tanks have been successfully integrated into space structures for decades. Comparable tanks for the safe storage of liquified natural gases are commonly used for land and sea based mobile applications. A transfer of regulations and guidance material from branches related to the aviation domain need to be carefully investigated in order to secure high safety standards.

The core of your work comprises the identification and documentation of requirements demanded from a regulatory perspective which govern the thermo-mechanical sizing and design of the LH2 storage system.

The following working steps are planed:

• familiarize yourself with the European aviation legislation (Part 21, Subpart J)
• understand the challenges which are linked to the integration of an LH2 Tank into an aircraft structure
• integrate into the surrounding research activities
• perform a literature research focused on the aviation branche (CS 23, CS 25 incl. AMCs, GM)
• perform a literature research in related branches
• critically elaborate transferability
• derive load assumptions
• formulate a margin policy proposal (optional)