USA As Represented by Secretary of the Navy

Other

Ephraim Gutmark

Klaus C Schadow

Kenneth Jay Wilson

Robert A Smith

Kenneth L Wilson

Timothy P Parr

Robert Smith

Donna M Hanson-Parr

Richard A Stalnaker

An improved technique for the active control of various combustion devices. This improved technique employs a flame kernel pulse actuator which produces periodic flame kernels by a spark ignition of a stoichiometric air and fuel mixture upstream of the combustion chamber. The discrete flame kernels are convected in a duct of premixed fuel and air which produce discrete pressure oscillations due to the energy release as each discrete flame propagates. Because the source of the energy release is essentially a chemical reaction, the flame kernel pulse actuator is able to produce a substantial amount of energy release even at the high operating pressures which are often encountered in many operational environments. These pressure oscillations may be adjusted to suppress or augment any combustion induced pressure oscillations as well as act to modulate the mixing layer between the fuel and air, thus controlling the downstream combustion process. The flame kernel pulse actuator comprises an actuator housing, a secondary fuel injection system, and an igniter. The combination of the igniter and fuel injection system produces a plurality of discrete flame kernels which are convected downstream toward the combustion chamber. The present flame kernel pulse actuator further includes a pressure sensor which is positioned so as to measure the acoustic oscillations in the combustion chamber and a controller device which uses the output of the sensor to control the frequency, phase shift, and amplitude of the discrete flame kernels.

Method and apparatus for active control of combustion devices

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. A high combustion efficiency may also be achieved by actively synchronizing the periodic fuel injection with the formation of the vortices.

Method and apparatus for the active control of a compact waste

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.

Suppressor of oscillations in airframe cavities

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.

Combustion instability suppression in regenerative liquid propellant gun

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.

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Ridgecrest, CA, United States of America

Ephraim Gutmark