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A ramjet powered device that utilizes a novel swirl generator for rapidly and efficiently atomizing, vaporizing, as necessary, and mixing a fuel into an oxidant. The swirl generator converts an oxidant flow into a turbulent, three-dimensional flowfield into which the fuel is introduced. The swirl ge

A ramjet powered device that utilizes a novel swirl generator for rapidly and efficiently atomizing, vaporizing, as necessary, and mixing a fuel into an oxidant. The swirl generator converts an oxidant flow into a turbulent, three-dimensional flowfield into which the fuel is introduced. The swirl generator effects a toroidal outer recirculation zone and an inner central recirculation zone, both of which are configured in a backward-flowing manner that carries heat and combustion byproducts upstream where they are employed to continuously ignite a combustible fuel/oxidizer mixture in adjacent shear layers and stabilizes flame propagation and accelerates combustion throughout the entire combustor. The swirl generator provides smooth combustion with no instabilities and minimum total pressure losses and enables significant reductions in the L/D ratio of the combustor. Other benefits include simplicity, reliability, wide flammability limits and high combustion efficiency and thrust performance.

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1. A ramjet powered device comprising a ramjet engine that includes a combustor and a swirl generator, the combustor having an inlet, the swirl generator being coupled to the inlet of the combustor and operable for converting an oxidizer flow into a three-dimensional flowfield that includes a substa

1. A ramjet powered device comprising a ramjet engine that includes a combustor and a swirl generator, the combustor having an inlet, the swirl generator being coupled to the inlet of the combustor and operable for converting an oxidizer flow into a three-dimensional flowfield that includes a substantial tangential velocity component, the swirl generator including a flow defining means and a fueling means, the flow defining means being operable for effecting both an outer recirculation zone and a central recirculation zone in the combustor, the outer recirculation zone being toroidal in shape, the central recirculation zone being disposed inwardly of the outer recirculation zone, the fueling means being operable for fueling the outer and central recirculation zones;wherein heat and combustion by-products produced during combustion are carried upstream by the outer and central recirculation zones where the heat and combustion by-products are employed to continuously ignite a combustible fuel/oxidizer mixture in a shear layer adjacent each of the outer and central recirculation zones, which accelerate propagation of the flame into and throughout the core flowfield. 2. The ramjet powered device of claim 1, further comprising a nozzle coupled to an aft end of the combustor, the nozzle being selected from a group consisting of convergent and convergent/divergent nozzles.3. The ramjet powered device of claim 1, wherein the ramjet engine further comprises an inlet structure that is coupled to the swirl generator on a side opposite the combustor and configured to guide the oxidizer flow such that its velocity is substantially completely defined by an axial velocity component.4. The ramjet powered device of claim 3, wherein the inlet structure including a plurality of flow guide vanes for mitigating oxidizer flow distortions and flow separations in the oxidizer flow before the oxidizer flow enters the swirl generator.5. The ramjet powered device of claim 4, wherein the flow guide vanes are spaced apart so as to define a plurality of flow channels, each of the flow channels having a differently sized cross-section such that the flow channels produce a series of inlet flows that are substantially uniform in flow velocity.6. The ramjet powered device of claim 5, wherein the swirl generator includes a conduit through which is disposed at least one of a fuel conduit and an electrical cable, the conduit extending through at least one of the flow guide vanes, the inlet structure further comprising a fairing member that at least partially surrounds the conduit, the fairing member being operable for reducing flow separations that would otherwise be induced by the conduit.7. The ramjet powered device of claim 1, wherein the flow defining means includes a swirl vane pack having a plurality of vanes and wherein the vanes are configured to provide the swirl vane pack with a swirl number that is less than about 2.0.8. The ramjet powered device of claim 7, wherein the swirl number of the swirl vane pack is about 0.4 to about 1.2.9. The ramjet powered device of claim 1, wherein the combustor has a length-to-diameter ratio that is less than about 2.0.10. The ramjet powered device of claim 9, wherein the length-to-diameter ratio is less than about 1.6.11. The ramjet powered device of claim 10, wherein the length-to-diameter ratio is about 1.0.12. The ramjet powered device of claim 1, further comprising a booster engine that is configured to accelerate the ramjet powered device to a predetermined takeover speed where thrust production is assumed by the ramjet engine.13. The ramjet powered device of claim 12, wherein the booster engine is a rocket that employs a solid propellant.14. The ramjet powered device of claim 12, wherein the booster engine is ejectable after the ramjet powered device has been accelerated to the predetermined takeover speed.15. A ramjet powered device comprising a ramjet engine having a combustor and a swirl generator, the 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 that serves 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 combustor inlet, 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 coupled to the swirl vane pack so as to extend rearwardly therefrom, 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;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. 16. The ramjet powered device of claim 15, further comprising a booster engine that is configured to accelerate the ramjet powered device to a predetermined takeover velocity where thrust production is assumed by the ramjet engine.17. The ramjet powered device of claim 16, wherein the booster engine is a rocket that employs a solid propellant.18. The ramjet powered device of claim 17, wherein the booster engine is ejectable after the ramjet powered device has been accelerated to the predetermined takeover velocity.19. The ramjet powered device of claim 15, wherein at least one of the fuel injectors is housed in the centerbody assembly.20. The ramjet powered device of claim 15, wherein the plurality of injectors include a plurality of strut injectors coupled to the inlet housing and the centerbody assembly, each of the strut injectors including a plurality of fuel injection sites.21. The ramjet powered device of claim 15, wherein an outer wall of an aft end of the centerbody assembly has a shape selected from a group of shapes consisting of convergent-divergent shapes and convergent shapes.22. The ramjet powered device of claim 21, wherein a plurality of injection sites are formed about the centerbody downstream of the swirl vanes.23. The ramjet powered device of claim 21, wherein the aft end of the centerbody has a shape that is selected from a group consisting of a frusto-conical shape and an ogive shape.24. The ramjet powered device of claim 23, wherein a plurality of channels are formed into a perimeter of the aft bluff boat-tail body.25. The ramjet powered device of claim 15, wherein the swirl generator further comprises at least one igniter, the igniter being coupled to one of the centerbody assembly, the inlet housing and the combustor, the igniter being operable for generating an ignition kernel that ignites the fuel/oxidizer mixture in the central recirculation zone.26. The ramjet powered device of claim 25, wherein the igniter is housed in the centerbody assembly.27. The ramjet powered device of claim 26, further comprising a second igniter coupled to the combustor at a location downstream of the dump step.28. The ramjet powered device of claim 25, wherein the igniter is selected from a group of igniters consisting of spark igniters, plasma jet igniters, laser-based igniters and microwave based igniters.29. The ramjet powered device of claim 15, wherein the combustor has a length-to-diameter ratio that is less than about 2.0.30. The ramjet powered device of claim 15, wherein an inlet ramp is formed onto the inlet housing adjacent the dump step.31. The ramjet powered device of claim 30, wherein a plurality of circumferentially spaced apart channels are formed into the inlet ramp, the channels enhancing turbulent transport and fine scale mixing.32. The ramjet powered device of claim 30, wherein a plurality of circumferentially spaced apart injection sites are formed into the inlet ramp, the injection sites comprising at least a portion of the fuel injectors.33. The ramjet powered device of claim 15, wherein the inlet of the combustor includes a quarl expansion.34. The ramjet powered device of claim 15, wherein the vanes are configured to provide the swirl vane pack with a swirl number that is less than about 2.0.35. The ramjet powered device of claim 15, wherein the swirl number of the swirl vane pack is about 0.4 to about 1.2.