Thermal model to aid the conceptual design of hydrogen storage vessels for aviation applications

Hydrogen is deemed a viable contender to make the aviation industry more sustainable. However, while its mass-energy density of 120 MJ/kg with a density of 70 kg/m³ is an improvement with respect to the energy density of 43 MJ/kg of conventional aviation fuels, it's volumetric energy density of only 8 MJ/m³ is four times larger, which inevitably has a detrimental effect on the aircraft's aerodynamics. Accordingly, the fuel shall be stored under pressure and at low temperatures to achieve the assumed density values. The actual values for the storage pressure and temperature are topics of discussion. This research aims at studying the effects of storing liquid or gas hydrogen on the mission of an aircraft, by investigating the temperature and pressure profile during such a mission. During this study, multiple tank configurations and aircraft missions are investigated. Using a two-phase hydrogen approach an increase in the gravimetric efficiency by a factor of two can be achieved, compared to gas hydrogen. Moreover, trends have been found in the definition of the topology of hydrogen tanks for different aircraft missions. Increasing design freedom by allowing multiple tanks shows that the loss in gravimetric efficiency is limited to 10%.