Abstract: The utility model relates to a noise reduction device for an outlet side of a fan, and a heat exchange system including the noise reduction device. The noise reduction device includes: a connecting portion configured to be connected with at least a part of the air duct cover, and form an accommodation space communicating with an airflow on the outlet side via at least one of the through holes; and at least one first chamber and/or at least one second chamber, the first chamber being located in the accommodation space and filled with a sound-absorbing material, and the second chamber being located in the accommodation space and configured as a resonant noise-reduction cavity. The utility model is easy to manufacture, install and maintain, the noise reduction effect is obvious, and therefore the utility model has significant practicability.

Abstract: An exhaust processing system that includes: an exhaust passageway for directing exhaust gases, the exhaust passageway having passageway walls that define and enclose the exhaust passageway between an upstream position and a downstream position; and an acoustic liner formed against and covering at least one of the passageway walls of the exhaust passageway. The acoustic liner may include uniformly configured modular acoustic blocks fitted against each other. The modular acoustic blocks each may include interior cavities having different lengths configured to dampen targeted sound frequencies.

Abstract: A method of erecting an acoustic shell for stage performances, the shell have frame defining a concave volume that is curved in two orthogonal planes and has an inner surface facing forwardly of a stage for a performance. A plurality of polygonal acoustic panels are positioned in the frame and spaced in rows and column along the inner surface, each panel having an outer acoustically active surface. The frame is formed of plural curved trusses each with a base for support on the stage and a peak. An oculus ring is connected to the peak of each arch and the bases of the arches are space along a bottom curve of the concave volume. The panels comprise plural adjacent blocks in rows and columns, each with a base and inner closed end, the length of each block being different for adjacent blocks.

Abstract: An acoustic shell for stage performances has a frame defining a concave volume that is curved in two orthogonal planes and has an inner surface facing forwardly of a stage for a performance. A plurality of polygonal acoustic panels are positioned in the frame and spaced in rows and column along the inner surface, each panel having an outer acoustically active surface. The frame is formed of plural curved trusses each with a base for support on the stage and a peak. An oculus ring is connected to the peak of each arch and the bases of the arches are space along a bottom curve of the concave volume. The panels comprise plural adjacent blocks in rows and columns, each with a base and inner closed end, the length of each block being different for adjacent blocks.

Abstract: The passive edge-tone suppression method includes the step of inserting a central insertion tube within a nozzle to disturb jet oscillations in a flow field of an edge-tone feedback loop. The central insertion tube can have a diameter of 200 micrometers and can be inserted within a center of the nozzle. The method also includes the step of extending the central insertion tube through the nozzle and into an alignment with the edge producing the edge tone. Further, the method includes the step of increasing a length of the central insertion tube in relation to a stand-off distance between the nozzle and the edge. The length of the central insertion tube can be increased to a length of about 30 percent of the stand-off distance.

Abstract: A mixing device having a chamber is provided. The chamber includes an inlet, a main body, and a flow axis. The main body is configured for containing a fluid circulating generally along the flow axis. The inlet is configured to receive at least one fluid stream and is oriented in a flow plane generally perpendicular to the flow axis. A plurality of mixing channels that each receive portions of the fluid stream from the inlet are provided. The plurality of mixing channels are each oriented along the flow plane and have unequal distinct lengths configured to release the portions of the fluid stream into the chamber at discrete time intervals.

Abstract: A silencer for a gas turbine includes a first duct portion; a second duct portion connected to the first duct portion, the first and second duct portions forming an elbow region at the connection; and a plurality of elbow shaped vanes provided in the elbow region. The plurality of elbow shaped vanes have equal lengths and are spaced equally apart.

Abstract: A noise attenuation device for testing a jet engine.

Abstract: A device for simulating sound produced by certain equipment, for example a rotor-stator arrangement of a turbomachine, or for generation of opposing sound fields for active sound control, including active sound reduction and active sound amplification, comprises flow obstacles (2) provided in a flow duct (1) flown by a fluid at which vortices (5, 6) are shed at a certain frequency depending on the shape and size of the flow obstacles and the velocity of flow. The quantity and spatial arrangement of the flow obstacles is selected such that a periodically spatially and temporally changing pressure field for the excitation of a sound field (8) of a certain modal content is produced by the entirety of the vortices shed. This sound field reacts synchronizingly on the vortex shedding. The resonant circuit so formed, whose vortex shedding frequency is in the range of the resonant frequency of the sound field to be excited, is the sound source.

Abstract: The present invention provides support means for an acoustic liner in an APU exhaust system, where the acoustic liner has a tubular sidewall with an outer surface, a first longitudinal edge, a second longitudinal edge, and an axial gap formed between the first and the second longitudinal edges. The APU exhaust system includes an annular support disposed substantially symmetrically about a longitudinal axis and coupled to a portion of the acoustic liner and a linear support disposed at least partially in the acoustic liner axial gap.

Abstract: Repairs and overhaul procedures are scheduled and implemented with a surprisingly low frequency. Repair and overhaul procedures are implemented wherein conventional noise suppression exhaust sound attenuation systems receive structural and functional enhancements for promoting longevity of efficient system operations. Degradation deficiencies of conventional configurations of sound attenuation systems for exhaust augmenters and deflector panels are avoided or prevented so that insulation re-packing rates may be minimized. Apparatus and associated methodology establish and implement maintenance protocols for installing specially-designed kits in existing sound attenuation systems.

Abstract: Methods and apparatus are provided for an exhaust duct having an externally replaceable acoustic liner. The exhaust duct includes a forward section that is configured to be axially coupled with a bulkhead collar on the aircraft, a body section that is coupled to the forward section and a stinger cap that includes the replaceable acoustic liner. The replaceable acoustic liner is configured to be slideably received by the body section.

Abstract: The exhaust created from the operation of pneumatic tools can create a considerable amount of noise. The present disclosure includes a detachable muffler apparatus used to reduce the sound during the operation of a pneumatic tool. The muffler apparatus includes a flexible outer housing that defines a muffler passage extending between a muffler inlet and a muffler outlet. The flexible outer housing includes an attachment end that defines the muffler inlet and a distal end that defines the muffler outlet. The attachment end can be removably attached to a pneumatic tool body by a fastener. Tool exhaust is forced through and around folds within at least one sheet of permeable material positioned within the muffler passage.

Abstract: A serviceable muffler (20) has an end plate (34) releasably clamped (36) to an open end (30) of a muffler body (26) and permitting access to an internal catalytic or filter element (28) for removal and replacement. An apertured flange (44) has an outer border with flared rounded portion (46) complemental to flared rounded portions (40 and 42) of each of the end plate (34) and the open end (30) of the body (26), and having an inner border defined by an aperture (48) through which the element (28) is removed and replaced. Servicing and manufacturing methods are provided.

Abstract: A compressed air muffler comprises a rear attachment section, a compressed air muffler section adjoining it in the longitudinal direction with a compressed air muffler body of a porous compressed air muffler material and an outlet duct extending in the length direction as far as a front outlet opening, such outlet duct having in the muffler section, a form tapering toward the outlet opening. The muffler body has a bare outer peripheral face, its outer periphery face constituting an outlet face for the compressed air flowing through its wall athwart the longitudinal direction. The duct section extending through the attachment section, of the outlet duct merges steplessly with the duct section running in the muffler section.

Abstract: A sound producing vehicle exhaust system comprises a housing positionable over an exterior end of a vehicle tailpipe. A turbine has at least one support plate. The support plate is rotatable about a central axis of rotation with the housing and has a plurality of angular blades with interior ends coupled to the support plate for rotation there with. At least one facing disk is positioned within the housing adjacent to the turbine. A central axis is provided through the facing disk and support plate. At least one bearing pin is provided. The bearing pin rotatably couples the support plate to the facing disk. A plurality of apertures extend through the facing disk. In this manner exhaust gasses from a tailpipe will pass through the blades and create a turbine-like sound.

Abstract: A compressed air muffler comprises a rear attachment section, a compressed air muffler section adjoining it in the longitudinal direction with a compressed air muffler body of a porous compressed air muffler material and an outlet duct extending in the length direction as far as a front outlet opening, such outlet duct having in the muffler section, a form tapering toward the outlet opening. The muffler body has a bare outer peripheral face, its outer periphery face constituting an outlet face for the compressed air flowing through its wall athwart the longitudinal direction. The duct section extending through the attachment section, of the outlet duct merges steplessly with the duct section running in the muffler section.

Abstract: A new and improved exhaust system as described herein, wherein the catalytic cartridge is selectively replaceable. The catalytic cartridge, which contains the catalyst, is located within the baffle tube. The baffle tube is easily inserted and removed from the housing assembly of the exhaust system, thereby making it simple and efficient to remove and replace the catalytic cartridge.

Abstract: A muffler arrangement includes an exhaust-gas muffler (4), which is subdivided into an inlet space (9) and an outlet space (10). An exhaust-gas stub (3) of an internal combustion engine (1) opens into the inlet space (9). Exhaust gas is conducted from the outlet space (10) into an air channel (15) via an exhaust-gas outlet (12). The air channel (15) is formed between the housing (4c) of the exhaust-gas muffler (4) and an outer cover (16) and extends along a side of the exhaust-gas muffler (4). A cooling-air component flow (18) is branched from a cooling-air flow of a cooling-air blower (5) and enters at a first end (25) of the air channel (15). The cooling-air component flow (18) exits again at the other second end (35) of the air channel (15).

Abstract: A mountable discharge pipe for an end muffler has devices for fastening the discharge pipe to an end muffler housing. A hook provided on the discharge pipe can be suspended at the end muffler housing, and a holding lug provided with an opening is arranged at the discharge pipe. The holding lug can be fastened by way of a nut-bolt connection on the end muffler housing. As a result, an easily mountable fastening of a discharge pipe on an end muffler is achieved.

Abstract: A sound attenuating device including a sound insulating structure and a windband. The sound insulating structure is constructed and arranged to receive vented air from an exhaust vent. The windband is affixed to the sound insulating structure and is constructed and arranged to prevent water from entering the sound insulating structure. The windband also provides a structure for attenuating sound.

Abstract: An air intake muffler for a heater, especially a motor vehicle heater, with a hollow body (7) of sound-absorbing material which is surrounded by a muffler chamber (2) and is penetrated by a cavity (8) which is flush with an inlet connection (9) and an outlet (10) of the muffler chamber (2) which can be connected to an air intake opening of the heater. To reliably prevent water or moisture from penetrating into an assembly downstream of the muffler (1), it is provided that the muffler chamber (2) is downstream of a water separator which has a water separation chamber (3) with at least one air intake opening (20 to 23) in its wall located laterally offset relative to the inlet of the muffler chamber (2) and which is separated from the muffler chamber by a deflector wall (24 to 27) which prevents direct flow from the air intake opening to the inlet connection (9).

Abstract: Silencer for gas discharge device employing easily replaceable cartridge utilizing juxtapositioned layers of wire mesh and porous resilient material which dissipate the energy stored in an exhaust system and deflect under pressure of the exhaust gases to provide a self cleaning function and a cylindrical liner mounted within the cartridge comprising the same or larger wire mesh and wire diameter size than used in the cartridge for capturing the large particles of the exhaust gases before they pass through the layers of wire mesh forming the cartridge.

Abstract: Methods and apparatus for suppressing cell howl with negligible impact on engine test conditions are described. The apparatus, in an exemplary embodiment includes a flow distorter configured to be positioned close to a nozzle exit of an engine nozzle, and a flow distorter support for maintaining the flow distorter at a selected location. The flow distorter is adjustably secured to the support so that a distance at which a tip of the distorter is located relative to support is adjustable.

Abstract: A noise reduction system is provided for installation on a bypass turbine having a core engine, an outer casing and a thrust reverser. The system is comprised of an acoustically treated nose cowl conventional for the engine; a respaced inlet guide vane upstream of the core engine for reducing wake disturbances striking the engine fan; a flow diverter downstream of the core engine for turning fan air inward toward the engine center line and for turning core air outward; a structure for supporting and positioning said flow diverter relative to the engine; a core flow expansion chamber device for slowing the peak velocity of the exhaust gas prior to exhausting it to the atmosphere; and an acoustic tailpipe assembly configured to define an outlet area sized and shaped to compensate for the mass flow loss created by the core flow expansion chamber device.

Abstract: Apparatus for reducing the pressure and thermal impingement effects of a supersonic exhaust gas plume emanating from a rocket motor nozzle. A pair of wedge-shaped pieces comprise a disrupter positioned on opposite sides of the central longitudinal axis of the rocket exhaust plume in order to disrupt and disperse the plume concentration. The positioning of these pieces is such that at least a portion of the exhaust gas plume may pass between them. The disrupter defines a flow area normal to the central axis of the exhaust flow which is less than the cross sectional area of the exhaust plume at the position of the disrupter pieces. The reduced flow area causes the exhaust flow to undergo a normal shock wave adjacent the position of the disrupter device before the exhaust gases pass between the disrupter body pieces at subsonic velocity.

Abstract: The present invention relates to a ground test installation for the jet engines (5A, 5B) of an airliner (2) equipped with at least two jet engines linked to the wings of the aircraft, comprising, for each jet engine (5A, 5B), a silencer (8A, 8B) having a body of generally cylindrical elongate shape, said silencers being intended to each be arranged behind the nozzle of one of said jet engines. According to the invention, this installation comprises a casing (6) which is acoustically insulating and permeable to air, intended to envelop at least the front part of the fuselage (3) and the wings (4A, 4B) of the aircraft (2), and the rear wall of which (7A, 7B) is connected to the front end part of each of said silencers (8A, 8B).

Abstract: The invention provides a device for collecting the exhaust gas jet of an aircraft reactor with orientable propulsion nozzle or with a gas jet orientable with respect to the longitudinal axis of said reactor, during ground testing of the latter, as well as a testing installation for aircraft reactors equipped with said device. The device comprises an external cylindrical jacket bell-mouthed at its end intended to be situated opposite the tested reactor and a cylindrical internal jacket, concentric to said external jacket and intended for straightening out the exhaust gas jet when this latter or the propulsion nozzle of the tested reactor has a slant with respect to the axis of said reactor.

Abstract: An apparatus for reducing the pressure and thermal impingement effects of a supersonic exhaust gas plume emanating from a rocket motor nozzle. A disrupter body positioned within the exhaust plume along the central longitudinal axis thereof disrupts and disperses the plume concentration. The body has a central passage through which a portion of the exhaust may pass. The body and passage are sized and shaped to provide a flow area normal to the exhaust flow less than the cross-sectional area of the exhaust plume at the position of the body. The reduced flow area causes the exhaust flow to undergo a normal shock wave upstream of the body before passing through and around the body at a subsonic velocity. The presence and configuration of the body disrupts and disperses the plume concentration, and the reduced flow velocity significantly reduces the downstream pressure and thermal effects of the exhaust gas plume.

Abstract: A dissipator device comprises a container having an inlet for connection to a rocket exhaust and a plurality of exhaust orifices of smaller dimensions than the inlet for exhaust flow out of the container in a plurality of different directions. A deflector member is positioned in the container in alignment with the inlet in the path of incoming exhaust gases for deflecting the flow. A disrupter member is positioned between the inlet and deflector member, and has a through bore defining an orifice of area less than the exhaust flow area at the plane of the disrupter member, so that exhaust gases flow both through and around the disrupter member, substantially reducing the downstream pressure and impingement heat transfer.

Abstract: Two groups of half shells capable of being retracted from the jet flow, in a position closing the jet pipe. The thrust reverser and the silencer are concentric and their axes of rotation are upstream with respect to their position in the jet flow.

Abstract: Gas turbine exhaust quieting means wherein the low frequency noise which is normally generated by turbulence in the gas turbine exhaust, is suppressed by means of a turbulence suppressing flow distributor. Said flow distributor comprising an elongated, hollow body, having a multiplicity of small holes in the walls thereof. Said flow distributor also providing a means for uniformly distributing the gas turbine exhaust flow over the face of a turbular or splitter type of exhaust gas silencer, which is usually used in combination with the flow distributor.