Researchers at Washington State University have successfully demonstrated the use of liquid hydrogen as a unique fuelling system for powering unmanned aerial vehicles (UAVs).
Described by the researchers as a major milestone, the test used a liquid hydrogen gas station to fill a liquid hydrogen tank, providing the hydrogen for a fuel cell power conversion system used to fly a medium-sized UAV, simulating the energy demands for a flight.
“Using hydrogen fuel for aviation is a hot topic,” said Jake Leachman, Associate Professor in the School of Mechanical and Materials Engineering who is leading the WSU project. “Folks are warming up to the idea, and we have gotten a few years head start. A UAV is a great testing ground,” he said.
“Many companies have attempted liquid hydrogen flights with a marginal record,” said Leachman, who started the student effort. “It says something about Patrick and Ian that this work has continued and is succeeding.”
Over the last decade, the WSU team developed a unique liquid hydrogen storage tank that will eventually be used onboard to power flights. Liquid hydrogen occupies a lot less space than hydrogen gas, providing more fuel and allowing longer flights. The tank is made of a lightweight polymer instead of metal.
WSU is one of the few places in the country where polymer materials can be tested at the very low temperatures required for liquid hydrogen storage. The tank also saves weight by having a heat exchange system within its tank wall to warm the hydrogen vapor. The hydrogen gas is then used to power a fuel cell that creates electricity to power the UAV.
The researchers hope to begin testing the liquid hydrogen power on real flights later this year.