Researchers at the FAMU-FSU College of Engineering are designing an innovative system that enables hydrogen to function not only as a clean fuel source but also as an integrated cooling medium for critical systems within electric-powered aircraft.
Their design focuses on a 100-passenger hybrid-electric aircraft, and it addresses the complexities of using liquid hydrogen not only as a clean fuel but also as an integrated cooling medium for critical systems.
Liquid hydrogen’s extremely low density requires storage at -253°C, which demands considerable space and specialized cryogenic tanks. The researchers approached the cryogenic tanks and their associated subsystems to optimize storage.
They define an index that focuses on the percent of fuel compared with the fuel mass of the entire system to rate the efficiency of different configurations. Through iterative adjustments, they achieved a configuration where 62% of the system’s total weight is usable hydrogen fuel.
In addition to storage, the system efficiently manages thermal loads. The ultra-cold hydrogen is routed through heat exchangers to capture waste heat from superconducting generators, power electronics, motors, and cables of the aircraft. This process raises the hydrogen’s temperature, preheating it before it enters the fuel cells and turbines.
Furthermore, the team has engineered a pump-free system that uses tank pressure to regulate the flow of hydrogen fuel, ensuring adequate fuel delivery during all flight phases.
This pressure regulation is reached by inserting hydrogen gas from a high-pressure cylinder to raise pressure and escaping hydrogen vapor to reduce it. They adjust tank pressure in real-time by using a loop, which connects pressure sensors to the aircraft’s power demand.
In simulations, the system’s ability is enough to meet the demands of takeoff or emergency maneuvers as it can deliver hydrogen at rates up to 0.25 kilograms per second,
The heat exchangers are arranged strategically, first cooling cryogenic components, then absorbing heat from higher-temperature components, and finally preheating the hydrogen for the fuel cells.
The current study has concentrated on design optimization and system simulation. In the next phase, experimental validation will be conducted.
This project is a key part of NASA’s Integrated Zero Emission Aviation program, a collaborative effort aimed at developing a comprehensive suite of clean aviation technologies.
