Abstract: This invention relates to air breathing engines, such as ramjets, scramjets and internal combustion, and more particularly to an active combustion control device for a combustor. In more particularity, the present invention relates to a method and apparatus that applies active combustion control technology to advanced propulsion devices and closed-loop fuel injection at sub-harmonic frequencies of the instability frequency of the combustor. The problem of limited actuator frequency response is addressed by injecting fuel pulses at sub-harmonic frequencies of the instability. The fuel may be liquid, solid or gas. To achieve this desired result, a closed loop controller is designed to determine sub-harmonic frequencies using a divider to divide the instability frequency of a combustor, yielding a fraction of the harmonic frequency.

Abstract: This invention relates to air breathing engines, such as ramjets, scramjets and internal combustion, and more particularly to an active combustion control device for a combustor. In more particularity, the present invention relates to a method and apparatus that applies active combustion control technology to advanced propulsion devices and closed-loop fuel injection at sub-harmonic frequencies of the instability frequency of the combustor. The problem of limited actuator frequency response is addressed by injecting fuel pulses at sub-harmonic frequencies of the instability. The fuel may be liquid, solid or gas. To achieve this desired result, a closed loop controller is designed to determine sub-harmonic frequencies using a divider to divide the instability frequency of a combustor, yielding a fraction of the harmonic frequency.

Abstract: This invention relates to air breathing engines, such as ramjets, scramjets and internal combustion, and more particularly to an active combustion control device for a combustor. In more particularity, the present invention relates to a method and apparatus that applies active combustion control technology to advanced propulsion devices and closed-loop fuel injection at sub-harmonic frequencies of the instability frequency of the combustor. The problem of limited actuator frequency response is addressed by injecting fuel pulses at sub-harmonic frequencies of the instability. The fuel may be liquid, solid or gas. To achieve this desired result, a closed loop controller is designed to determine sub-harmonic frequencies using a divider to divide the instability frequency of a combustor, yielding a fraction of the harmonic frequency.

Abstract: This invention relates to air breathing engines, such as ramjets, scramjets and internal combustion, and more particularly to an active combustion control device for a combustor. In more particularity, the present invention relates to a method and apparatus that applies active combustion control technology to advanced propulsion devices and closed-loop fuel injection at sub-harmonic frequencies of the instability frequency of the combustor. The problem of limited actuator frequency response is addressed by injecting fuel pulses at sub-harmonic frequencies of the instability. The fuel may be liquid, solid or gas. To achieve this desired result, a closed loop controller is designed to determine sub-harmonic frequencies using a divider to divide the instability frequency of a combustor, yielding a fraction of the harmonic frequency.

Abstract: This invention relates to air breathing engines, such as ramjets, scramjets and internal combustion, and more particularly to an active combustion control device for a combustor. In more particularity, the present invention relates to a method and apparatus that applies active combustion control technology to advanced propulsion devices and closed-loop fuel injection at sub-harmonic frequencies of the instability frequency of the combustor. The problem of limited actuator frequency response is addressed by injecting fuel pulses at sub-harmonic frequencies of the instability. The fuel may be liquid, solid or gas. To achieve this desired result, a closed loop controller is designed to determine sub-harmonic frequencies using a divider to divide the instability frequency of a combustor, yielding a fraction of the harmonic frequency.

Abstract: The present invention relates to a method and device for controlling the solid fuel regression rate of a solid fuel ramjet engine. In a preferred embodiment of the present invention, pressure oscillations are excited using active, closed-loop control to vary the heat transfer, and in turn the regression rate of a solid fuel ramjet engine. The pressure oscillations are excited by introducing small disturbances into the shear layer. The disturbances are amplified in the shear layer and excite pressure oscillations. The disturbances are introduced at a certain phase relative to the pressure oscillations. This is accomplished by closed-loop control. By varying the phase, the amplitude of the pressure oscillations can also be varied, which in turn will vary the heat transfer, regression rate, and thrust level.

Abstract: An apparatus for the disposal of solid rocket motors which produce exhaust ases containing flammable and/or explosive products. The solid rocket motor to be burned is first detachably connected to and inserted in one end of an elongated mixing chamber which has, at an opposite end, a multi-step expansion nozzle. The rocket motor is then ignited and the exhaust gas is passed into the mixing chamber, which is sufficiently large to reduce the velocity of exhaust gases from supersonic to subsonic. Air is injected into the mixing chamber to react with flammable and/or explosive products in the exhaust gases and the resultant mixture is then discharged from the mixing chamber through a multi-step expansion nozzle to expand the gaseous mixture and, at the same time, produce substantial turbulence within the gas mixture which is about six times higher than the turbulence levels produced by a constant area circular nozzle.

Abstract: The present invention relates to an electric valve capable of producing podic mass-flow modulation of a gaseous, liquid, or mixed-phase medium over wide ranges of frequencies, pressure, and flow rates. Such mass-flow modulation can be used to periodically shed large-scale vortices at the outlet and to manipulate their dynamics allowing the user to actively control fluid mixing and transport further downstream. The device has a piezoelectric wafer that in a relaxed state abuts the upstream end of the outlet tube separating the pressurized fluid in the plenum with the outlet. The device has an apparatus for applying electric field to the wafer, which distorts the wafer and ruptures the seal forming a throat area that controls the fluid mass flux. Due to the fast response of the piezoelectric material to an electric field, the throat area can be modulated rapidly in time making the device operable even at high frequencies.

Abstract: A shear layer of a fluid flow has relatively large vortical structures generated by acoustic forcing from oscillations induced in a cavity closely adjacent to the flow so that these structures enhance mixing at the layer. The forcing frequency is selected by varying the dimensions of the cavity, and several cavities of different dimensions may be provided for forcing at different frequencies, including beat frequencies. The cavity provides passive, high amplitude forcing effective with a compressible shear layer due to high speed flow, including supersonic flow. Cavities of differing configuration provide forcing for fluid flow from nozzles of different geometries. The most effective enhancement is provided by particular excitation frequencies generated by a cavity having a size selected in accordance with dimensionless relations between the flow parameters and nozzle geometry.

Abstract: An improved method and apparatus for actively controlling a combustion process such as a waste incinerator by means of a spatial and temporal synchronized injection of fuel. The improved method and apparatus employs an active control system which controls the intentional formation of large scale, coherent vortices and the synchronized injection of the fuel supply at various locations relative to the formation of the vortices. The preferred apparatus comprises an actuator or similar structure that is adapted for producing and stabilizing discrete, large scale vortices in a combustion device. In addition, another device controls or modulates the injection of the fuel into the vortices at the optimal location and timing relative to the vortex cycle. As applied to an incinerator, this method can be optimized to ensures that the fuel and waste are introduced into the highest temperature locations, were extended residence times are obtained by trapping the fuel and waste inside the vortices.

Abstract: The oscillations found to occur in the cavities of an structural frame moving through a fluid are substantially eliminated by the adoption of perturbation elements located at the leading edge of the cavity and reflecting any remaining oscillations out of the cavity at the trailing edge. The perturbation elements may take the form of multiple pins of various shape and geometrical arrangement which prevents the generation and growth of vortices causing acoustic oscillations. The reflection of remaining oscillations out of the cavity may be accomplished by ramping the trailing edge of the cavity.

Abstract: A regenerative liquid propellant gun and pertains includes a modified contional fixed bolt extending into a conventional combustion chamber of the regenerative liquid propellant gun. The modified fixed bolt of this invention provides for improved operation of the otherwise conventional regenerative liquid propellant gun and has modified end portion embodiments and internal propellant injection passages, all for the purpose of creating turbulent propellant flow.

Abstract: The invention is directed to a fluid mixing device in which a jet of first luid is passed through a nozzle having a conical inlet section and a noncircular, elongated, exit section. The jet of first fluid mixes with a second fluid located downstream of the device. In operation, the intersection of the conical and elongated sections produces axial rotation in the first fluid. Intense, three-dimensional, axial and circumferential vortical structures are created. These structures then interact with the high modes of azimuthal instabilities that are common to the elongated configuration. The jet of first fluid evolves into two secondary jets, generating a double shear layer inside the flow. Highly efficient mixing of the fluids, in both the outside and inside (core) segments of the jet, is achieved within a relatively small mixing space.

Abstract: A new solution monopropellant for use in liquid propellant guns is composed f ammonium nitrate, hydrazine hydrate, and water in a mole ratio of 1:1:0.05 to 0.30.

Abstract: The overall efficiency of a reaction engine having primary and secondary combustion chambers is greatly improved by reducing the primary exhaust velocity to subsonic speed. This is accomplished in a preferred embodiment by using an exhaust tube downstream of the primary nozzle. A tube diameter of about six times that of the primary throat diameter and a tube length of about five to ten times that of the tube diameter is considered optimum.

Abstract: A method and apparatus for improving combustion efficiency in external bung assisted projectiles by providing a stepped configuration of the projectile body and placing the injector ports in the recirculation zone created behind said step near the base of the projectile.

Abstract: A method and apparatus for improving combustion efficiency in external bung assisted projectiles by slowing te exit speed of fuel-rich exhaust gases to subsonic flow.

Abstract: In a solid fuel ramjet in which a fluid flow boundary layer extends along a urning fuel grain and receives combustible material liberated from the grain, exciting oscillations in air flowing toward the grain so that oscillations continue in the boundary layer and promote vortices in the layer to mix the air and the combustible material.

Abstract: In a combustor in which a flow area for fuel and air increases suddenly at dump so as to generate vortices which mix the fuel and air for combustion downstream of the dump, the improvement in which the flow cross section upstream of the dump is noncircular, as triangular or rectangular, causing flow downstream of the dump to be noncoherent so that mixing by the vortices is aperiodic with the result that heat release on mixing is uniform in time and does not drive oscillations in the combustor.