Undersea Application of a Closed Brayton Cycle Powerplant

The design criteria for an undersea powerplant application are reviewed. A closed Brayton cycle power system utilizing the catalytic combustion of hydrogen and oxygen as a heat source is described. System operation is at a design depth of 20,000 ft for a 50-kW rated output. The total system weight and volume is shown for various endurance missions, as well as a weight and volume breakdown for the closed Brayton cycle plant, reactants, pressure vessels, and buoyancy material. An alternative closed Brayton powerplant design, utilizing a high frequency output alternator, is compared with the reference 400 Hz design. By utilizing a higher shaft speed, the closed Brayton loop pressure level can be increased, which will reduce the size and weight of the closed loop heat exchanger components. The rotating unit size is also significantly reduced.