Abstract: A method of reducing noise from a combustor of a gas turbine engine includes the steps of establishing a maximum noise limit that may be for a particular frequency range. A primary fuel flow percentage, which may be emitted from a fuel nozzle arrangement having various groupings of simplex and duplex nozzles, is then established. An immersion depth measured between an aft rim of a swirler and a distal tip of the fuel nozzles may then be reduced thereby reducing the noise amplitude.

Abstract: An assembly is provided which includes a swirler and a fuel nozzle. The swirler includes an outer wall, an inner wall, an outer passage and an inner passage. The outer wall circumscribes the inner wall and extends axially along an axis to a distal outer wall end. The inner wall extends axially along the axis to a distal inner wall end that is axially recessed within the swirler from the distal outer wall end. The outer passage is radially between the inner wall and the outer wall. The inner passage is radially within the inner wall. The fuel nozzle projects into the inner passage. The fuel nozzle includes a plurality of fuel outlets and a plurality of air outlets. The fuel outlets are axially aligned with the inner wall. The air outlets are axially upstream of and radially outboard of the fuel outlets.

Abstract: A method of reducing noise from a combustor of a gas turbine engine includes the steps of establishing a maximum noise limit that may be for a particular frequency range. A primary fuel flow percentage, which may be emitted from a fuel nozzle arrangement having various groupings of simplex and duplex nozzles, is then established. An immersion depth measured between an aft rim of a swirler and a distal tip of the fuel nozzles may then be reduced thereby reducing the noise amplitude.

Abstract: A method for thermally-sensitive coating analysis of a component includes imaging the coated, exposed component over a range of distinct frequencies as selected by a narrowband variable filter; estimating parameters of non-uniformity correction (NUC) for every pixel at every wavelength; constructing a 2D temperature map on a pixel-by-pixel basis using the non-uniformity correction; and mapping the 2D temperature map to a 3D computer aided design (CAD) model.

Abstract: A method for thermally-sensitive coating analysis of a component includes imaging the coated, exposed component over a range of distinct frequencies as selected by a narrowband variable filter; estimating parameters of non-uniformity correction (NUC) for every pixel at every wavelength; constructing a 2D temperature map on a pixel-by-pixel basis using the non-uniformity correction; and mapping the 2D temperature map to a 3D computer aided design (CAD) model.

Abstract: A gas burner for low NOx gas furnaces is disclosed with improved flame carryover for igniting one or more adjacent burners. The burner includes a burner tube that receives a mixture of fuel and air. The burner tube is coupled to an outlet. The outlet includes a primary outlet opening which is in communication with at least one transverse slot for communicating a flame to at least one adjacent burner. The primary outlet opening may be elliptical and the outlet further may also include a concave outer face through which the primary outlet opening extends. The at least one slot may include a pair of oppositely directed transverse slots extending outward from the primary outlet opening along a semi-minor axis of the primary outlet opening.

Abstract: A method of reducing noise from a combustor of a gas turbine engine includes the steps of establishing a maximum noise limit that may be for a particular frequency range. A primary fuel flow percentage, which may be emitted from a fuel nozzle arrangement having various groupings of simplex and duplex nozzles, is then established. An immersion depth measured between an aft rim of a swirler and a distal tip of the fuel nozzles may then be reduced thereby reducing the noise amplitude.

Abstract: An improved induced draft gas burner assembly for low NOx residential and light commercial gas furnaces is disclosed. The improved burner includes an upstream assembly coupled to a fuel inlet and an air inlet. The air inlet is coupled to a neck extending between the air inlet and the outlet of the neck, both of which may be disposed within an optional chamber. If used, such a chamber also includes an outlet coupled to a burner. In practice, the chamber and neck behave as a Helmholtz resonator that can be tuned to provide an upstream impedance Zup that exceeds the downstream impedance Zdown of the components downstream of the burner assembly.

Abstract: A burner for use with an induced draft furnace and which satisfies reduced nitrous oxide (NOx) emission standards is disclosed. The burner may employ a mechanical swirler that introduces a rotational vector to the emitted air and fuel mixed by the burner. By introducing the rotational vector, the resulting flame is more stable and sustainable even with the relatively low air flow afforded by an induced system. Such flame stability can be enhanced by positioning the burner directly within an inlet to a heat exchanger and manufacturing the inlet with reception surfaces that form a frusto-conically shaped flame expansion zone. In doing so, a secondary source of air is avoided and NOx emissions are reduced.

Abstract: An ignition system for a multi-burner heat exchanger assembly, a furnace, and a method using same are disclosed. The assembly may include a plurality of adjacent heat exchanger tubes, with a burner associated with each tube. All the burners may be lit with a single igniter and no source of secondary air. To do so, each of the burners may be provided so as to generate a swirling exit flow of combustion gases. One or more carryover tubes may also be connected between adjacent pairs of heat exchanger tubes or adjacent pairs of burners. The swirling flow generated by the burners causes hot combustion gases to move through the carryover tubes to thus carry the flame from one burner to the next. Not only can a single igniter be used, but a single flame sensor as well, while at the same time reducing nitrogen oxide emissions.

Abstract: A gas burner for low NOx gas furnaces is disclosed with improved flame carryover for igniting one or more adjacent burners. The burner includes a burner tube that receives a mixture of fuel and air. The burner tube is coupled to an outlet. The outlet includes a primary outlet opening which is in communication with at least one transverse slot for communicating a flame to at least one adjacent burner. The primary outlet opening may be elliptical and the outlet further may also include a concave outer face through which the primary outlet opening extends. The at least one slot may include a pair of oppositely directed transverse slots extending outward from the primary outlet opening along a semi-minor axis of the primary outlet opening.

Abstract: A burner for use with an induced draft furnace and which satisfies reduced nitrous oxide (NOx) emission standards is disclosed. The burner may employ a mechanical swirler that introduces a rotational vector to the emitted air and fuel mixed by the burner. By introducing the rotational vector, the resulting flame is more stable and sustainable even with the relatively low air flow afforded by an induced system. Such flame stability can be enhanced by positioning the burner directly within an inlet to a heat exchanger and manufacturing the inlet with reception surfaces that form a frusto-conically shaped flame expansion zone. In doing so, a secondary source of air is avoided and NOx emissions are reduced.

Abstract: A system for reducing compressor noise includes a rotor having a plurality of blades. The blades have a nominal geometry characterized by a blade parameter. At least some of the blades are mistuned, such that they differ from the nominal geometry by greater than a manufacturing tolerance in the blade parameter. The blades produce shock waves at a blade passing frequency, and the mistuned blades shift acoustic energy away from the blade passing frequency to multiple lower amplitude tones at other frequencies. The system is configurable to be deployed with an inlet silencer that preferentially absorbs acoustic energy at some of the shifted frequencies.

Abstract: An ignition system for a multi-burner heat exchanger assembly, a furnace, and a method using same are disclosed. The assembly may include a plurality of adjacent heat exchanger tubes, with a burner associated with each tube. All the burners may be lit with a single igniter and no source of secondary air. To do so, each of the burners may be provided so as to generate a swirling exit flow of combustion gases. One or more carryover tubes may also be connected between adjacent pairs of heat exchanger tubes or adjacent pairs of burners. The swirling flow generated by the burners causes hot combustion gases to move through the carryover tubes to thus carry the flame from one burner to the next. Not only can a single igniter be used, but a single flame sensor as well, while at the same time reducing nitrogen oxide emissions.

Abstract: A furnace with a burner is disclosed. The burner may include an area expansion plenum, a burner tube, a heat exchanger, a gas valve, an igniter, and an induced-draft blower. The gas valve may meter gas into the area expansion plenum, while the induced-draft blower may draw air into the area expansion plenum, wherein air and gas may mix to produce a lean gas/air mixture. The lean gas/air mixture may then be pulled through the burner tube and into the heat exchanger. Within the heat exchanger, the lean gas/air mixture may be ignited and energy may be produced, exciting acoustic energy in the heat exchanger. The acoustic energy may be distributed out of the heat exchanger by the area expansion plenum. In order to distribute the acoustic energy, the cross sectional area of the area expansion plenum may be greater than the cross sectional area of the burner tube.

Abstract: An improved induced draft gas burner assembly (31, 131, 231, 331, 431, 531, 631) for low NOx residential and light commercial gas furnaces (10, 10a) is disclosed. The improved burner includes an upstream assembly coupled to a fuel inlet (55) and an air inlet (43). The air inlet (43) is coupled to a neck (41, 141, 241, 341, 441, 541, 641) extending between the air inlet (43) and the outlet of the neck (41, 141, 241, 341, 441, 541, 641), both of which may be disposed within an optional chamber (42, 142, 242, 342, 442). If used, such a chamber (42, 142, 242, 342, 442) also includes an outlet coupled to a burner (46, 146, 246, 346, 546, 646). In practice, the chamber (42, 142, 242, 342, 442) and neck (41, 141, 241, 341, 441, 541, 641) behave as a Helmholtz resonator that can be tuned to provide an upstream impedance Zup that exceeds the downstream impedance Zdown of the components downstream of the burner assembly (31, 131, 231, 331, 431, 531, 631).

Abstract: A system for reducing compressor noise includes a rotor having a plurality of blades. The blades have a nominal geometry characterized by a blade parameter. At least some of the blades are mistuned, such that they differ from the nominal geometry by greater than a manufacturing tolerance in the blade parameter. The blades produce shock waves at a blade passing frequency, and the mistuned blades shift acoustic energy away from the blade passing frequency to multiple lower amplitude tones at other frequencies. The system is configurable to be deployed with an inlet silencer that preferentially absorbs acoustic energy at some of the shifted frequencies.

Abstract: An augmentor system minimizes acoustic pressure fluctuations on the heat release process within the augmentor by staggering the vanes therein. The alternating axial vane stagger pattern arranges the downstream set of vanes as baffles which prevent the propagation of tangential acoustic waves between the vanes to protect the upstream set of vanes from the effects of transverse acoustic velocity fluctuations which minimizes screech without substantially affecting augmentor performance.

Abstract: An augmentor system minimizes acoustic pressure fluctuations on the heat release process within the augmentor by staggering the vanes therein. The alternating axial vane stagger pattern arranges the downstream set of vanes as baffles which prevent the propagation of tangential acoustic waves between the vanes to protect the upstream set of vanes from the effects of transverse acoustic velocity fluctuations which minimizes screech without substantially affecting augmentor performance.