Method and apparatus for active control of combustion devices

Abstract

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.