Aviation Week Article: Pratt & Whitney Unveils Details Of Hydrogen-Steam Hybrid Engine Cycle

Pictured: Air enters a small reverse-flow core at the rear of the engine, powering the fan and then exiting via an evaporator, condenser and water separator. | Credit: Pratt & Whitney

Guy Norris at Aviation Week reports, "Hydrogen fuel may offer attractive pathways toward the goal of zero carbon emissions, but turning that vision into a practical propulsion system is another matter. Now Pratt & Whitney thinks it may have taken the first steps along that path with the Hydrogen Steam-Injected, Intercooled Turbine Engine (HySIITE) concept-a novel hybrid engine configuration that combines the advantages of the fuel's cryogenic properties with the thermodynamic benefits of steam injection. Pratt & Whitney has unveiled details of the concept, which has been studied under a two-year $3.8 million U.S. Energy Department Advanced Research Projects Agency-Energy (ARPA-E) effort. While Pratt acknowledges the cycle is complex and requires more study, it is encouraged by the results, which show potential for as much as 35% lower energy use compared with current state-of-the-art engines."
Full Story (Aviation Week)