Compact lightweight ramjet engines incorporating swirl augmented combustion with improved performance

A method comprising:

• providing a device having a core turbojet engine, a ramjet engine and a flow controller, the flow controller having a forward moveable element and an aft moveable element the forward moveable element being movable between a first position, in which an air intake of the ramjet engine is closed and atmospheric air is permitted to flow into the core turbojet engine, and a second position in which atmospheric air is permitted to flow only into the ramjet engine, the aft moveable element being movable between a first position, in which an exit of the ramjet is closed and an exit of the core turbojet engine is open to permit exhaust gas to flow therethrough, and a second position in which the exit of the nozzle is open and the exit of the core turbojet engine is closed;
• positioning each of the forward and aft moveable elements in their respective first positions if a velocity of the device is less than a first transition velocity and operating only the core turbojet engine;
• and
• operating both the core turbojet engine and the ramjet engine if the velocity of the device is not less than the first transition velocity and is less than a second transition velocity.

An apparatus for producing propulsive thrust comprising:

• a core turbojet engine having a low pressure compressor, a high pressure compressor, a combustor, and a turbine;
• a ramjet engine having a swirl generator and a ramjet combustor, the ramjet combustor having a combustor inlet, the swirl generator having an inlet housing, a swirl vane pack, a centerbody assembly, and a plurality of fuel injectors, the inlet housing being coupled to the combustor inlet and defining a hollow interior volume therein, the inlet housing serving as a conduit through which an oxidizer flow is conducted, the hollow interior volume intersecting the combustor inlet at a dump step wherein the inlet housing has an inner dimension that is smaller than that of the ramjet combustor, the swirl vane pack being disposed within the hollow interior volume and having a plurality of vanes, the vanes cooperating to change the velocity of the oxidizer flow so that the velocity includes a substantial tangential velocity component, the centerbody assembly being disposed in the hollow interior volume and being coupled to the swirl vane pack so as to extend rearwardly therefrom, and the plurality of fuel injectors being coupled to at least one of the inlet housing, the swirl vane pack and the centerbody assembly and dispensing a fuel therefrom directly into the oxidizer flow for at least partially mixing the fuel and oxidizer prior to entering the ramjet combustor, wherein the swirl generator converts the oxidizer flow received therein into a swirling, three-dimensional flowfield, wherein a first portion of the flowfield flows over the dump step to form an outer recirculation zone, wherein a second portion of the flowfield forms a central recirculation zone that is anchored by an aft end of the centerbody assembly, wherein a first portion of the fuel mixes with the first portion of the flowfield to fuel the outer recirculation zone, wherein a second portion of the fuel mixes with the second portion of the flowfield to fuel the central recirculation zone, and wherein a remaining portion of the fuel enters and fuels a core flow;
• and
• a flow controller coupled to the turbojet engine and the ramjet engine, the flow controller having at least one forward moveable element and at least one aft moveable element, the at least one forward moveable element being movable between a first position, in which the air intake of the ramjet engine is closed and atmospheric air is permitted to flow into the low pressure compressor of the core turbojet engine, and a second position in which atmospheric air is not permitted to flow into the lower pressure compressor of the core turbojet engine and the air intake of the ramjet engine is open, the at least one aft moveable element being movable between a first position, in which an exit of the nozzle is closed and an exit of the core turbojet engine is open to permit exhaust gas to flow therethrough, and a second position in which the exit of the nozzle is open and the exit of the core turbojet engine is closed;
• wherein when a velocity of the apparatus is less than a predetermined first transition velocity, the forward and aft moveable elements are positioned in their respective first positions and the core turbojet engine is operable for producing all of the propulsive thrust, and when the apparatus has a velocity that is not less than the predetermined transition velocity the ramjet engine is operable for producing at least a portion of the propulsive thrust.