Abstract: The present invention comprises methods for detecting and controlling flame blowout in combustors. The blowout precursor detection system comprises a combustor, a blowout precursor detection unit, a pressure measuring device and/or an optical measuring device. The methods of the present invention comprise receiving optical data measured by an optical measuring device, performing one or a combination of raw data analysis, spectral analysis, statistical analysis, and wavelet analysis on received optical data, and determining the existence of a blowout precursor based on such analyses. The present invention further comprises closed-loop control methods for controlling a combustor to prevent blowout.

Abstract: A method for combusting a combustible fuel includes providing a vessel having an opening near a proximate end and a closed distal end defining a combustion chamber. A combustible reactants mixture is presented into the combustion chamber. The combustible reactants mixture is ignited creating a flame and combustion products. The closed end of the combustion chamber is utilized for directing combustion products toward the opening of the combustion chamber creating a reverse flow of combustion products within the combustion chamber. The reverse flow of combustion products is intermixed with combustible reactants mixture to maintain the flame.

Abstract: A combustor assembly includes a combustor vessel having a wall, a proximate end defining an opening and a closed distal end opposite said proximate end. A manifold is carried by the proximate end. The manifold defines a combustion products exit. The combustion products exit being axially aligned with a portion of the closed distal end. A plurality of combustible reactant ports is carried by the manifold for directing combustible reactants into the combustion vessel from the region of the proximate end towards the closed distal end.

Abstract: Systems and methods for manipulating acoustic energy are presented. In some embodiments, a combustion zone provides heat to a regenerator using a mean flow of compressible fluid. In other embodiments, a thermoacoustic driver is concentrically disposed within a shell to permit radial heat transfer from the thermoacoustic driver to compressible fluid within the shell, thereby preheating the compressible fluid within the shell. In other embodiments, burning of a combustible mixture within the combustion zone is pulsed in phase with the acoustic pressure oscillations to increase acoustic power output.

Abstract: Thermoacoustic devices are disclosed wherein, for some embodiments, a combustion zone provides heat to a regenerator using a mean flow of compressible fluid. In other embodiments, burning of a combustible mixture within the combustion zone is pulsed in phase with the acoustic pressure oscillations to increase acoustic power output. In an example embodiment, the combustion zone and the regenerator are thermally insulated from other components within the thermoacoustic device.

Abstract: Thermoacoustic devices are disclosed wherein, for some embodiments, a combustion zone provides heat to a regenerator using a mean flow of compressible fluid. In other embodiments, burning of a combustible mixture within the combustion zone is pulsed in phase with the acoustic pressure oscillations to increase acoustic power output. In an example embodiment, the combustion zone and the regenerator are thermally insulated from other components within the thermoacoustic device.

Abstract: Systems and methods for manipulating acoustic energy are presented. In some embodiments, a combustion zone provides heat to a regenerator using a mean flow of compressible fluid. In other embodiments, a thermoacoustic driver is concentrically disposed within a shell to permit radial heat transfer from the thermoacoustic driver to compressible fluid within the shell, thereby preheating the compressible fluid within the shell. In other embodiments, burning of a combustible mixture within the combustion zone is pulsed in phase with the acoustic pressure oscillations to increase acoustic power output.

Abstract: A system for real time identification of modes of oscillation includes a sensor, an observer, a controller and an actuator. The sensor senses a controlled system such as a combustor, and generates a signal indicative of the modes of oscillation in the controlled system. For example, these modes of oscillation can be combustion instabilities. The observer receives the signal from the sensor, and uses the signal to determine modal functions and frequencies of the modes of interest with a pair of integrals with changing time limits. The controller receives the modal functions and frequency for each mode of interest from the observer, and effects a gain and phase shift for each mode. Based on the modal functions, the frequency, the gain and the phase shift, the controller generates and outputs a control signal, that is supplied to the actuator. The actuator controls the modes of oscillation of the controlled system, based on the control signal.

Abstract: A system for real time identification of modes of oscillation includes a sensor, an observer, a controller and an actuator. The sensor senses a controlled system such as a combustor, and generates a signal indicative of the modes of oscillation in the controlled system. For example, these modes of oscillation can be combustion instabilities. The observer receives the signal from the sensor, and uses the signal to determine modal functions and frequencies of the modes of interest with a pair of integrals with changing time limits. The controller receives the modal functions and frequency for each mode of interest from the observer, and effects a gain and phase shift for each mode. Based on the modal functions, the frequency, the gain and the phase shift, the controller generates and outputs a control signal, that is supplied to the actuator. The actuator controls the modes of oscillation of the controlled system, based on the control signal.

Abstract: A pulse combustor apparatus for burning solid fuel comprises a Rijke-type combustor tube and has a rotating fuel bed for defining a primary combustion zone adjacent the fuel bed. The rotating fuel bed tends to minimize agglomeration of solid fuel and accumulation of ash during combustion by agitating the solid fuel. An inlet conduit is provided for introducing a low nitrogen gaseous fuel to the combustion air upstream of the combustion zone to minimize the formation of NO.sub.x in the primary combustion zone. In other embodiments, inlets are provided downstream of the primary combustion zone for introducing additional air or gaseous, low nitrogen fuel for air staging or reburning to minimize the emission of NO.sub.x. Sorbents, such as limestone, are introduced above the bed to minimize SO.sub.2 emissions.

Abstract: An improved flame holder based tunable pulse combustor, and a processing system employing same. The processing system is for thermal, chemical, and physical processes which employ natural acoustic modes in a processing chamber to enhance the processing. An acoustically resonant processing chamber is provided as the processing vessel. A frequency tunable pulse combustor comprising a flame holder is positioned to excite natural acoustic modes in the processing chamber. Material introduced into the processing chamber is thereby subjected to acoustic pulsations while the material is being processed. The acoustic excitations in the system result in improved moisture removal and particle heating. Also disclosed are various embodiments of frequency and amplitude tunable pulse combustors which may be employed to excite the natural acoustic modes in the processing chamber, including axially translatable acoustic decoupler and flame holder configurations.

Abstract: A pulse combustor apparatus adapted to burn either a liquid fuel or a pulverized solid fuel within a preselected volume of the combustion chamber. The combustion process is substantially restricted to an optimum combustion zone in order to attain effective pulse combustion operation.

Abstract: An improved flame holder based tunable pulse combustor, and a processing system employing same. The processing system is for thermal, chemical, and physical processes which employ natural acoustic modes in a processing chamber to enhance the processing. An acoustically resonant processing chamber is provided as the processing vessel. A frequency tunable pulse combustor comprising a flame holder is positioned to excite natural acoustic modes in the processing chamber. Material introduced into the processing chamber is thereby subjected to acoustic pulsations while the material is being processed. The acoustic excitations in the system result in improved moisture removal and particle heating. Also disclosed are various embodiments of frequency and amplitude tunable pulse combustors which may be employed to excite the natural acoustic modes in the processing chamber, including axially translatable acoustic decoupler and flame holder configurations.

Abstract: An improved pulsating processing system for thermal, chemical, and physical processes which employs nonlongitudinal acoustic modes in a processing chamber to enhance the processing. An acoustically resonant processing chamber is provided as the processing vessel. A frequency tunable pulse combustor or other selectively variable frequency acoustic exciter is positioned to excite natural nonlongitudinal acoustic modes in the processing chamber. Material introduced into the processing chamber is thereby subjected to nonlongitudinal acoustic pulsations while the material is being processed. Also disclosed is an improved frequency and amplitude tunable pulse combustor which may be employed to excite the natural acoustic modes in the processing chamber. One disclosed embodiment is a system for drying a slurry of material such as kaolin. The nonlongitudinal acoustic excitations in the system result in improved moisture removal and particle heating.

Abstract: An improved pulsating processing system for thermal, chemical, and physical processes which employs nonlongitudinal acoustic modes in a processing chamber to enhance the processing. An acoustically resonant processing chamber is provided as the processing vessel. A frequency tunable pulse combustor or other selectively variable frequency acoustic exciter is positioned to excite natural nonlongitudinal acoustic modes in the processing chamber. Material introduced into the processing chamber is thereby subjected to nonlongitudinal acoustic pulsations while the material is being processed. Also disclosed is an improved frequency and amplitude tunable pulse combustor which may be employed to excite the natural acoustic modes in the processing chamber. One disclosed embodiment is a system for drying a slurry of material such as kaolin. The nonlongitudinal acoustic excitations in the system result in improved moisture removal and particle heating.

Abstract: A pulse combustor apparatus including a combustor tube having open ends and containing at least one combustion zone where combustion of a fuel occurs and heat is released, resulting in the formation of a standing acoustic mode with nodes and anti-nodes in the tube. The combustion zone is located approximately half the distance between the acoustic pressure node and anti-node where the acoustic pressure oscillation lags the acoustic velocity oscillation by approximately one-quarter wavelength of the oscillation. Furthermore, the combustion air must flow towards the acoustic pressure anti-node. The fundamental principle relating to the occurrence of the pulsations in the combustor is the interaction between the combustion processes and both the non-zero acoustic velocity and acoustic pressure oscillations at the designated combustion zone location.