Hydrogen‐Powered Aircraft

Abstract

Hydrogen is the most abundant species on Earth. It may be obtained from a variety of sources and may be compressed to cryogenic temperatures for ease of handling and distribution. The only products resulting from the combustion of liquid hydrogen are nitrogen oxides and water vapor whose effects on climate may be mitigated by optimizing cruising altitudes and mixture conditions in the combustion chamber. As such, hydrogen is a promising aviation fuel that addresses both the environmental and air quality problems associated with conventional jet fuels and the depletion of fossil resources. Nevertheless, several technical challenges remain. Although liquid hydrogen has a greater specific energy density compared to conventional jet fuels, it also has a four times smaller volumetric energy density. This poses a unique challenge for the efficient design of hydrogen‐powered aircraft and associated fuel systems. Finally, the wide use of liquid hydrogen as an aviation fuel requires further development of materials and tanks for its efficient distribution and storage at cryogenic temperatures, the development of heat exchange systems for engine cooling, and the efficient control of thermal stresses on structural components.