Abstract: A heat exchanger includes one or more passages and one or more metal foam sections adjacent the passage to promote an exchange of heat relative to the passage. The metal foam section includes a nominal thermal conductivity gradient there though to provide a desirable balance of heat exchange properties within the metal foam section.

Abstract: A heat exchanger includes one or more passages and one or more metal foam sections adjacent the passage to promote an exchange of heat relative to the passage. The metal foam section includes a nominal thermal conductivity gradient there though to provide a desirable balance of heat exchange properties within the metal foam section.

Abstract: A fuel system for a propulsion system includes a fuel deoxygenating device and a catalytic module containing catalytic materials. The fuel deoxygenating device removes dissolved oxygen from the fuel to prevent formation of insoluble materials that can potentially foul the catalyst and block desirable catalytic reactions that increase the usable cooling capacity of an endothermic fuel.

Abstract: A fuel system for a propulsion system includes a fuel deoxygenating device and a catalytic module containing catalytic materials. The fuel deoxygenating device removes dissolved oxygen from the fuel to prevent formation of insoluble materials that can potentially foul the catalyst and block desirable catalytic reactions that increase the usable cooling capacity of an endothermic fuel.

Abstract: A pulse detonation engine (10) is provided with an aerovalve (14) for controlling the pressure of injected propellants (Ox, Fuel) in an open-ended detonation chamber (26). The propellants are injected at such pressure and velocity, and in a direction generally toward a forward thrust wall end (16) of the detonation chamber (26), an aerovalve (14) is formed which effectively inhibits or prevents egress of the propellant from the detonation chamber (26). A shock wave (34) formed by the injected propellant acts, after reflection by the thrust wall end (16) and in combination with the aerovalve (14), to compress and conserve, or increase, the pressure of the injected propellant. Carefully timed ignition (28) effects a detonation pulse under desired conditions of maintained, or increased, pressure. Termination of the propellant injection serves to “open” the aerovalve (14), and exhaust of the combusted propellants occurs to produce thrust.