Electrical power generation for sustained high speed flight

This proposal seeks to develop a novel method for the extraction of significant electrical power from air breathing hypersonic vehicles by using the existing large temperature differential between the surface of the material inside the SCRAM engine and the temperature of the fuel which is also being used to cool that surface. Thermionic conversion is an attractive approach for power extraction since it does not involve any moving parts, requires no magnetic field, and is naturally suited to high temperature operation.  The proposed work will explore the potential for operating a thermionic device at power extraction levels higher than 50 kW per m2 along with configuring the materials and structures of such a system to provide multifunctional benefits to extract power and high temperature load bearing structural wall surface of the SCRAM jet engine.  A successful project will demonstrate through modeling and experiments the potential of a thermionic converter to operate in a high temperature-high current density regime.  In addition, the design and fabrication techniques for a practical structure for implementation of this device in a SCRAM jet engine will be developed. BENEFIT: On board thermionic power generation for SCRAM jet powered aircraft is an attractive approach for generating significant auxiliary electrical power.  Because these vehicles do not have a turbine in the engine, they must carry all elements of an auxiliary power system, including both an energy source, such as batteries, and a power conditioning systems.  A vehicle with thermionic power generation has no need for an energy source since the power can be generated from the difference in temperature between the material inside the SCRAM engine and the temperature of the fuel which is being used to cool that surface; therefore, such a system offers significant weight savings.  If the thermionic device works with high efficiency, it could be used for high temperature energy conversion in other applications as well. For example, it could be utilized for high temperature solar to electric conversion or topping cycles for furnaces.  )