摘要:
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). The volume of the chamber (42, 142, 242, 342, 442), the length and cross-sectional area and shape or geometry of the neck (41, 141, 241, 341, 441, 541, 641) provide convenient variables for manipulating Zup and stabilizing the flame. Various configurations of the neck (41, 141, 241, 341, 441, 541, 641) may be use to provide a sufficient volume thereby eliminating the need for the chamber (42, 142, 242, 342, 442).
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.