Florin Girlea

Integrated power generation, thermal management, and ballast control systems for an industrial, heavy lift, bouyancy based flight vehicle

Four separate demonstrator test platforms were designed, fabricated, and tested to validate the critical components of an integrated power generation, thermal management, and ballast control system, as designed for a heavy lift (500 ton), buoyancy based flight vehicle (Walrus). The Walrus flight vehicle uses liquid hydrogen as its primary fuel, due to the fuel’s extraordinary heat release per unit mass; thus, the demonstrator test platforms are linked by their use of gaseous or liquid hydrogen. The demonstrator platforms are as follows: 1) a counterflow cryogenic heat exchanger and evaporator designed to rapidly evaporate liquid hydrogen for consumption by power generation and ballast control systems, as well as provide integrated system cooling via an intermediate heat transfer fluid, 2) an innovative ultra-low temperature hydrogen PEM fuel cell, designed to simultaneously provide power for vehicle systems and condense liquid water byproduct for capture and use in the ballast control system, 3) a catalytic hydrogen-air burner, designed to provide heat to the ballast control system while burning hydrogen in a lightweight combustor, without the need of a separate ignition system and capable of burning at an equivalency ratio leaner than hydrogen’s traditional flammability limit, 4) a catalytic mass synthesis system, referred to as CMASS, which converts a portion of the vehicle’s hydrogen fuel supply and ambient air into gaseous ammonia (via a catalytic reaction vessel), which is subsequently liquefied and stored on board for the ballast control system. The CMASS system is designed to convert the liquid ammonia back into gaseous hydrogen for consumption by the power generation system after ballast control operations no longer require its presence. Taken together, these integrated hydrogen-based technology demonstrators show the synergy of integrating various vehicle subsystems by eliminating system redundancy and improving the overall performance, with respect to weight, volume, fuel consumption, and thermodynamic efficiency.