Catalytic pressurization of liquid hydrogen fuel tanks for unmanned aerial vehicles

Abstract

As the use and applications of Unmanned Aerial Vehicles (UAV) expand, the need for a lighter weight fuel allowing for longer duration flights has become the primary limiting factor in the advancement of these vehicles. To extend the operational envelope of UAV, onboard condensed hydrogen storage for missions exceeding one week is necessary. Currently, large spherical liquid hydrogen tanks that are pressurized with external helium tanks or electronic heating elements are utilized for this purpose. However, the mass, size, and power consumption of the fuel storage tank and fuel pressurization system significantly limit the flight envelope of UAV. In an effort to alleviate these issues, this paper investigates the technological feasibility of orthohydrogen-parahydrogen catalysis as a method of fuel pressurization. Typical pressurization requirements for takeoff, cruise, and landing are reviewed. Calculations of the catalyst system mass and response time are presented.