The gas turbine engine includes a fluid system fluidly connecting at least two components of the gas turbine engine, and a tunable resonator in fluid flow communication with the fluid system. The tunable resonator has a resonating volume that varies as a function of a volume of an inflatable member located inside the tunable resonator. The inflatable member having a means for varying the volume of the inflatable member, to thereby tune the resonating volume to a selected frequency of pressure fluctuations or acoustic waves within the fluid system.

An acoustic device includes: a perforated plate that has a plurality of holes penetrating in a plate thickness direction of the perforated plate and in which a main flow flows on one side of the perforated plate in the plate thickness direction; and a housing that is provided on the other side of the perforated plate in the plate thickness direction and partitions a space between the housing and the perforated plate, wherein part of the holes on the one side in the thickness direction is inclined to at least one of the one side and the other side of a flow direction of the main flow.

A combustor is provided with a combustion liner (12) in which a combustion gas flows through the inner peripheral side and a plurality of through-holes (14) are formed, and a sound attenuator (20) having a space-forming member (21) configured to form a space (S) connected to the plurality of through-holes (14) at the outer peripheral side of the combustion liner (12). The space-forming member has a main body having an opening configured to bring an outside and the space in communication with each other, and a lid joined to an outer surface of the main body via a welded portion and configured to protrude outward and close the opening.

Disclosed is a baffle for a mixing region of a furnace burner box, the mixing region being a volume in the burner box defined in a transverse direction between a burner at a front portion of the burner box and an opposing a rear portion of the burner box, a longitudinal direction between opposing side surfaces of the burner box, and a height-wise direction between opposing top and bottom surfaces of the burner box, the baffle having: a first side which is a rear side, a second side which is a front side, the first side and the second side being spaced in the transverse direction, and wherein the baffle defines an indirect fluid passageway between the first side and the second side.

An acoustic damper for a rotary machine includes at least one wall, at least one inlet, at least one outlet, at least one separating wall, and at least one neck. The wall extends from the back side of a combustor front panel and defines a damping chamber. The inlet is defined within the wall and is oriented to channel a flow of air into the damping chamber. The outlet is defined within the back side of the front panel. The separating wall is oriented to separate the damping chamber into a first volume and a second volume. The first volume of the damping chamber is configured to damp an acoustic pressure oscillation at a first frequency. The second volume of the damping chamber is configured to damp the acoustic pressure oscillation at a second frequency. The neck extends through the separating wall and is axially offset from the outlet.

A combustor component of a combustor for combusting fuel to produce a combustion gas includes a combustion cylinder forming a passage for the combustion gas, a first acoustic device which internally includes a first cavity communicating with the passage via a first through hole formed in the combustion cylinder, a second acoustic device which is located on a radially outer side of the first acoustic device so as to cover the first acoustic device, and internally includes a second cavity communicating with the passage via a second through hole formed in the combustion cylinder, and a first communication passage causing the first cavity and an outer space of the combustion cylinder to communicate with each other without via the first through hole and the second cavity.

A gas turbine engine has a resonator ring that is formed by two circumferentially extending rings. The first and second circumferentially extending rings have located within them baffles. Both the first ring and the second ring are able to mitigate acoustic frequencies generated by the gas turbine engine.

Heat-exchange and noise-reduction panel for a propulsion assembly, in particular for an aircraft, the panel comprising: a perforated plate comprising a plurality of through-openings; a cellular structure comprising longitudinally oriented structural walls covered by said perforated plate and comprising, between said walls, cavities that define Helmholtz resonators, said through-openings forming necks of said resonators; and means for the circulation of fluid, for example oil, at said perforated plate, wherein said fluid circulation means comprise channels that are formed at least in part in thickened ends of said walls on the same side as said perforated plate, and/or at least in part in regions of the perforated plate situated in the longitudinal extension of said thickened ends.

A sound level reducing apparatus and method for reducing the outdoor sound level produced by a high efficiency gas furnace. The apparatus comprising a muffler having an internal length determined by an identified target pure tone frequency producing an undesirable sound level. The internal length may be optimized to reduce the sound level across a range of operational frequencies.

An air intake coupling has at least one noise suppression hole formed therein. A gas-air mixer elbow is fluidly coupled to the air intake coupling. A burner box assembly is fluidly coupled to the gas-air mixer elbow via a gas-air plenum box. A heat-exchange tube has a first end that is fluidly coupled to the burner box assembly. A fan is fluidly coupled to a second end of the heat-exchange tube via a cold-end header box.