Abstract: Aircraft engine pod with acoustic attenuation.

Abstract: In order to reduce noise effectively and to provide a light-weight noise reducing apparatus and an exhaust nozzle for a jet engine, a mixer for mixing an exhaust gas and an external air is disposed behind an engine, a flow channel for accelerating an exhaust gas toward a mixer and a flow channel for introducing an external air to a mixer are formed by a flow channel forming section in a noise reducing mode.

Abstract: A box-shaped intake silencer for an engine is obtained by joining together an upper half and a lower half. The intake silencer includes a connecting duct for supplying air to the engine and an intake duct for bringing in outside air. The intake silencer brings in a blow-by gas generated by the engine and returns fresh air purified by a filter to the engine. The filter is inserted into a retaining part made up of the upper and lower halve and held at the retaining pat by joining the upper and lower halves together.

Abstract: A fan shroud includes a fan shroud portion having a surface including an aperture. A cooling fan is supported proximate to the aperture for permitting air flow through the fan shroud from the environment to the engine compartment. An air intake portion is supported on the fan shroud portion. The air intake portion and the fan shroud portion together define at least a portion of an air passageway having an inlet for receiving ambient air and an outlet for connection to an engine throttle. The fan shroud portion and air intake portion may respectively include first and second circumferential portions that define the air passageway.

Abstract: A device for noise configuration in a motor vehicle has a hollow body which is divided into at least two spaces. One space is connected to a gas-carrying part of an internal combustion engine arranged in the motor vehicle, and the other space is coupled acoustically to an interior and/or to an engine space of the motor vehicle and/or to the space surrounding the motor vehicle. The hollow body is divided into the two spaces by an essentially acoustically inactive wall. A vibrational element, which extends into both spaces, is arranged within the hollow body.

Abstract: In a head cover structure of a hermetic motor-driving type compressor, by comprising a front head cover having a space divided into a low-pressure side sucking a refrigerant by being installed a suction muffler and a high-pressure side discharging the refrigerant by an enclosure wall and a rear head cover combined to the rear surface of the front head cover and having a space divided into a low-pressure side and a high-pressure side by an enclosure wall, a flatness of the front head cover can be improved, leakage of a refrigerant gas from the high-pressure side can be prevented, and the cost of materials can be reduced by using an inexpensive steel material.

Abstract: At least a part of a duct wall of a suction duct is formed out of a molded body of non-woven fabric. The non-woven fabric contains a thermoplastic resin binder.

Abstract: A duct or conduit section (10) for installation, in particular, in an air intake system of an internal combustion engine, in which the duct section is composed of two shells (14) which are joined by a snap connection (15). Openings located in the parting seam or joint (16) between the shells (14) are produced by recesses in the half shells. These openings each have a cross-sectional area of less than 7 mm2 and are useful for suppressing noise resulting from the air intake. As a result of the openings, vibration-inducing forces exerted on adjacent components in the engine compartment due to pulsations in the intake tube, can be minimized or avoided. Also, the quantity of additional air drawn in from the engine compartment, which is undesired because it is too warm, is decreased.

Abstract: A silencer is disclosed with a bypass resonator (4; 9, 12) connected by at least one tubular connection (3a, 3b; 7, 8; 13) to a sound-transmitting channel (1). The tubular connection (3a, 3b) can have various lengths (La, Lb), tubular connections (7, 8) of different thicknesses can be connected, or the volume (V1, V2, Vn) of the bypass resonator (13) can be variable.

Abstract: A device for noise configuration in a motor vehicle has a hollow body which is divided into at least two spaces. One space is connected to a gas-carrying part of an internal combustion engine arranged in the motor vehicle, and the other space is coupled acoustically to an interior and/or to an engine space of the motor vehicle and/or to the space surrounding the motor vehicle. The hollow body is divided into the two spaces by an essentially acoustically inactive wall. A vibrational element, which extends into both spaces, is arranged within the hollow body.

Abstract: A box-shaped intake silencer for an engine is obtained by joining together an upper half and a lower half. The intake silencer includes a connecting duct for supplying air to the engine and an intake duct for bringing in outside air. The intake silencer brings in a blow-by gas generated by the engine and returns fresh air purified by a filter to the engine. The filter is inserted into a retaining part made up of the upper and lower halve and held at the retaining pat by joining the upper and lower halves together.

Abstract: A backpack frame for mounting a blower having an inlet port is provided with an intake air muffler on a surface facing the inlet port. The intake air muffler may be formed of a large number of through holes which are communicated with the backpack frame and have a small diameter and no angular portions, or a large number of dimples with a small diameter formed on the surface.

Abstract: A duct or conduit section (10) for installation, in particular, in an air intake system of an internal combustion engine, in which the duct section is composed of two shells (14) which are joined by a snap connection (15). Openings located in the parting seam or joint (16) between the shells (14) are produced by recesses in the half shells. These openings each have a cross-sectional area of less than 7 mm2 and are useful for suppressing noise resulting from the air intake. As a result of the openings, vibration-inducing forces exerted on adjacent components in the engine compartment due to pulsations in the intake tube, can be minimized or avoided. Also, the quantity of additional air drawn in from the engine compartment, which is undesired because it is too warm, is decreased.

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: A microporous sheet having both acoustical and structural functionality and a process for producing the sheet. Construction of the sheet requires, first of all, providing a sheet capable of functioning as a structural element of a component. A laser device capable of producing a free electron laser beam is provided, and the free electron laser beam is directed to a surface of the sheet to penetrate the sheet at a plurality of sites and thereby form a plurality of apertures. These apertures are generally uniformly dispersed and of a size and number sufficient to enable the sheet to function as an acoustical noise suppressor while retaining capability of functioning as a structural element.

Abstract: A gas turbine, a combined cycle plant and compressor by which both augmentation of the power output and augmentation of the thermal efficiency can be realized by injecting liquid droplets into inlet air introduced into an entrance of a compressor with simple equipment which is suitable for practical use. The gas turbine includes a compressor for taking in and compressing gas, a combustor in which fuel is combusted with the gas discharged from the compressor, and a turbine driven by the combusted gas of the combustor. The gas turbine further includes a liquid droplet injection device provided on the upstream side of the compressor for injecting liquid droplets into inlet air to be supplied into the entrance of the compressor to lower the temperature of the inlet air to be introduced into the compressor so that the injected liquid droplets may be evaporated while flowing through the compressor.

Abstract: An apparatus for reducing distortion of air flow entering the inlet of a fan. The device includes a perforated body member that has a first end that is attachable to the inlet end of the fan and a second end. The apertures in the body member are arranged in a plurality of circumferential rows. Preferably, the apertures in each successive row from the first end to the second end increase in diameter with the apertures in the row adjacent the first end being smaller in diameter than the apertures in the row adjacent the second end. The body member can be frustoconical, cylindrical or ellipsoidal in shape. In addition, the body member can be equipped with an apparatus for reducing airflow noise.

Abstract: In an aircraft turbine, an assembly consisting of an air inlet structure, a air blower housing (22) and a connecting part (36), is fitted in such a way as to reduce noise including in the junction area between the structure and the housing. The connecting part (36) is fastened onto a rear section (20'), not provided with a honeycomb core, of the internal wall (20) of the air inlet structure. A honeycomb structure (44) is fitted inside the air blower housing (22). The space inside the rear section (20') houses a forward extension (44') of the honeycomb structure (44), or a different honeycomb structure.

Abstract: An apparatus for reducing distortion of air flow entering the inlet of a fan. The device includes a perforated body member that has a first end that is attachable to the inlet end of the fan and a second end. The apertures in the body member are arranged in a plurality of circumferential rows. Preferably, the apertures in each successive row from the first end to the second end increase in diameter with the apertures in the row adjacent the first end being smaller in diameter than the apertures in the row adjacent the second end. The body member can be frusto-conical, cylindrical or ellipsoidal in shape. In addition, the body member can be equipped with an apparatus for reducing airflow noise.

Abstract: The present invention is noise attenuation system and related method for suppressing noise generated by a noise source, such as a jet engine, contained in a housing. An impedance device is positioned in the housing to attenuate the amplitude of sound waves generated by the noise source propagating in one direction and to create a reflected sound wave. The reflected sound wave is out of phase with the sound waves propagating from the noise source away from the impedance device. The reflected sound wave destructively interferes with this sound wave to attenuate the amplitude.

Abstract: An air intake system disposable in an air vehicle turbo engine housing disposed in an exterior airflow for selectively reducing external engine boundary layer separation drag and external engine friction drag on the engine housing comprising an air inlet member for receiving engine intake air disposable within the engine housing. The air intake system further comprising a first air exit port disposed in fluid communication with the air inlet member, adapted to direct intake air from the air inlet member and to direct intake air substantially in the direction of exterior airflow, to reduce external engine boundary layer separation drag. The air intake system further comprising a second air exit port disposed in fluid communication with the air inlet member, adapted to direct intake air from the air inlet member and to direct intake air substantially in a direction perpendicular to the exterior airflow, to reduce external engine friction drag.

Abstract: An extended reaction acoustic liner for use in jet engine noise mitigation has a substantially non-porous outer layer, a honeycomb core disposed in laminar juxtaposition to the outer layer, and a porous inner layer in laminar juxtaposition to the honeycomb core such that the honeycomb core is sandwiched between the outer layer and the inner layer. The honeycomb core comprises a plurality of cell walls defining a plurality of cells. Some of the cells are in fluid communication with one another via the openings formed in the cell walls. The openings in the cell walls cause viscous acoustic losses, resulting in acoustic energy dissipation and enhanced noise attenuation.

Abstract: In a scarfed nacelle inlet for channeling airflow to an engine having a longitudinal center line axis (ENGINE C/L), the duct including a crown (26) and a keel (28), an improvement including an inlet with a biplanar forward hilite. When viewed in side elevation, the biplanar hilite includes a first portion (40) including the keel, a second portion (42) including the crown, and a transition region (44) between the first and second portions. The first and second portions (40), (42) are linear and the transition region (44) is a single arc. An imaginary intersection line (IP) between the first and second portions is located vertically about midway between the crown and the keel.

Abstract: 058410796 In accordance with the present invention, in an air vehicle having a turbo engine including an inlet which receives intake airflow and is defined by an inner surface and a D-nose of the turbo engine, there is provided an inlet liner for improved acoustic, anti-ice and drag performance. The inlet liner is provided with a permeable acoustic layer formed to attenuate sound and defines the D-nose. The inlet liner is further provided with a pressurized fluid injecting device. The pressurized fluid injecting device is in fluid communication with the permeable acoustic layer and formed to inject fluid through the permeable acoustic layer at the D-nose to reduce drag of the intake airflow. The pressurized fluid injecting device is further formed to inject fluid through the permeable acoustic layer at a temperature sufficient to perform an anti-ice function at the D-nose.

Abstract: A silencer for reducing the noise emitted by the venting of a gas flow includes a tubular gas flow member having a sidewall, an open first end for connection to a gas supply, a closed second end and an opening in the sidewall for passage of gas from the interior of the gas flow member. The tubular gas flow member is surrounded by a porous noise-reducing member at least at the location of the opening in the sidewall of the gas flow member. A shell surrounds the noise-reducing member, and is provided with an opening for passage of gas which is spaced circumferentially from the opening in the sidewall of the gas flow member. In one embodiment, the noise-reducing member can be a wire mesh which is wrapped around the tubular gas flow member.

Abstract: An acoustic liner jet engine inlet barrel is formed from a perforated permeable skin, a honeycomb core, and a solid facesheet, each of which is formed in a one-piece configuration such that at most only a narrow single fore-to-aft splice, or no spice at all, is present in the finished product. The acoustic modal content remains unaffected, thus preserving a high degree of liner effectiveness, increasing the total active acoustic area of the barrel while decreasing its weight, and increasing its durability.

Abstract: Boundary layer separation at the boundary surface of an intake duct (18) of a turbofan aeroengine nacelle (12) at conditions of high incidence and high engine mass flow arises from shockwave induced pressure gradients in the boundary layer. To control separation, gaseous fluid is withdrawn from a high pressure region of the boundary layer at a downstream region of the boundary surface, conveyed within the intake duct structure (19) and discharged at an upstream region of the boundary surface into a low pressure region of the boundary layer.

Abstract: The invention relates to combined catalytic converter and muffler device intended for attachment to the exhaust pipe of an engine, e.g. on a lawn mower. The device comprises a housing within which a catalytic substance (14) is arranged. According to the invention, the exhaust gas inlet (3) is provided with a restriction, preferably in the form of a cone (6). Thereby, an intake of a suitable amount of air is achieved through an air inlet (7), preferably comprising an air labyrinth (8). The catalytic substance (14) is preferably provided in pellet form and arranged in an annular chamber in the housing, having a circular shape. A muffling substance (16) made of glass fibre ceramics is preferably arranged in a chamber (15) outside of the catalytic substance (14).

Abstract: A noise suppression system for a jet engine, the system having a substrate formed of open cell material, a layer of microporous material covering at least a portion of one surface of the substrate, a layer of substantially non-porous material covering at least one portion of an opposite surface of the substrate, and a pressurized air source for providing pressurized air to the substrate. The substrate, the microporous material, and the non-porous material are configured to define an inner surface of an inlet for the jet engine. The pressurized air is communicated from the substrate, through the microporous material, and into the inlet so as to provide a layer of less turbulent airflow along the inner surface of the inlet, thus mitigating noise generation.

Abstract: A turbomachine assembly includes a number of circumferentially spaced rotor blades, a number V of circumferentially spaced guide vanes axially adjacent to the rotor blades, an annular chamber surrounding the rotor blades, and an intake and exhaust for receiving and discharging air that passes through the annular chamber. When the turbomachine is in operation, spinning mode tones are generated by the interaction of the rotor and guide vanes. These tones are minimized by selecting a number of vanes relative to the number of blades so that selected tones propagate axial to the intake and exhaust of the turbomachine. A sound absorptive material is then positioned so that the tones impinge upon it. Moreover, a tuned duct is positioned in the path of the remaining tones. The turning vanes, placed within the tuned duct, cancel the remaining tones travelling through the duct.

Abstract: A noise controlling device (12) is used for controlling noise in a turbo-fan engine (10). The engine includes an entrance (22) for ingesting air, and a fan rotor (18) connected to a spinner (20) in the interior of the engine. The fan rotor faces the forward side of the engine. A ring (24) is connected to the interior of the engine, with the ring being located between the engine entrance and the forward side of the fan rotor. The inner periphery of the ring faces the spinner, with the ring surrounding the spinner in substantial coaxial alignment therewith. An acoustic lining (26) is disposed around the inner and outer peripheries of the ring.

Abstract: An acoustic liner jet engine inlet barrel is formed from a perforated permeable skin, a honeycomb core, and a solid facesheet, each of which is formed in a one-piece configuration such that at most only a narrow single fore-to-aft splice, or no splice at all, is present in the finished product. The acoustic modal content remains unaffected, thus preserving a high degree of liner effectiveness, increasing the total active acoustic area of the barrel while decreasing its weight, and increasing its durability.

Abstract: An electric motor assembly. An air-ventilated electric motor includes a motor housing having a cooling-air inlet and a cooling-air outlet. An outlet muffler array is located outside, and spaced apart from, the motor housing and includes two or more outlet mufflers each having a fluid entrance and a fluid exit. An outlet connecting duct has a first end connected to the cooling-air outlet of the motor housing and has a second end connected in parallel to the fluid entrances of each of the outlet mufflers. The assembly may also include an inlet muffler array and an inlet connecting duct.

Abstract: A noise attenuating air cleaner assembly for an internal combustion engines or the like operating in a dusty environment. The air cleaner assembly having a silencer assembly arranged concentric inside an air filter cartridge assembly and a noise attenuating end wall assembly closing an end of the air filter cartridge assembly attenuating air cleaner assembly to provide a source of clean air to the engine and to reduce transmitted induction noise.

Abstract: A lift truck having a hydraulic circuit with a muffler for reducing noise created by the hydraulic pump and motor assembly. The muffler includes a cylindrical body and first and second end caps which define an expansion volume which reduces the magnitude of pressure pulsations generated by the pump, thereby reducing noise. In one embodiment, the muffler includes mounting pads, located on the muffler body, for attaching the muffler to the truck frame, and a flexible hose interconnects the muffler and pump.

Abstract: A noise reduction kit is provided for installation on a bypass turbine engine having a core engine, an outer casing and a thrust reverser. The kit comprises a mixer downstream of the core engine for mixing fan air of the engine with the exhaust gas from the core engine to reduce the peak velocity of the exhaust gas; a structure for supporting and positioning said mixer relative to the engine; a spacer for extending the length of the exhaust gas flow path between said mixer and the thrust reverser to permit sufficient mixing of the fan air with the exhaust gas prior to reaching the thrust reverser; and an acoustic tail pipe assembly configured to define an outlet area for the engine exhaust gas flow path. The outlet area is sized and shaped to reduce pressure loss in the exhaust gas stream in an amount necessary to compensate for the pressure increase in the exhaust gas stream created by the mixer.

Abstract: An acoustic liner comprising a sound permeable inside plate forming a first closed annulus, and a sound impermeable outside plate forming a second closed annulus located outside of and extending around the first closed annulus. The inside and outside plates are spaced apart and thus form an annular chamber therebetween; and a core member is secured in this annular chamber, between the inside and outside plates. The core member forms or has the shape of a sine wave form annularly extending around the inside plate, and the core member and the inside plate form a multitude of varying depth sound absorption chambers to attenuate sound waves over a broad band of frequencies.

Abstract: The present invention relates to a novel sound attenuating laminate. More particularly, the invention relates to a simpler, lighter, and more effective noise attenuating laminate which is made up of seven layers of material. The laminate includes a duct liner, a moisture barrier, a first protecting layer, a screen, acoustic attenuating material, a second protecting layer, and a solid backing sheet. The laminate is readily incorporated into various sections of a jet engine compartment in order to attenuate the sound produced by the jet engine. Hollow rivets are used to conduct acoustical energy to the intermediary layers of the noise attenuating laminate.

Abstract: A noise suppression system for use with a jet aircraft engine having a plug support cylinder affixed to the engine, a tubular ejector shroud affixed to the engine and encompassing the plug support, the shroud having a reduced internal diameter adjacent the aft end and a plurality of spaced apart blow-in openings formed circumferentially about the shroud forward end providing passageways for the entrance of ambient air from the exterior to the interior of the shroud. A blow-in door is secured to the shroud for opening and closing each of the blow-in openings. A translating plug is supported on the plug support cylinder and is positionable between a forward position and an aft position and forms an annular exhaust nozzle between the exterior of the plug and the interior of the aft end of the shroud. A daisy mixing nozzle is positioned within the shroud aft of the blow-in doors, the nozzle being configured of a plurality of lobes providing undulating interior and exterior surfaces.

Abstract: A sound insulating lining for a gas flow path, particularly the bypass flow ath in a jet engine, is made up of a succession of acoustic panels including a perforated skin bonded to a stiffening frame, and a cellular structure formed by a ribbed skin clamped with prestressing via of resilient tongues to transverse struts of the stiffening frame so that the ribs engage the perforated skin to form resonant acoustic cavities. The panels forming the lining are screwed to the casing constituting the wall of the flow path to be insulated.

Abstract: An aircraft cowl, and in particular a translating cowl, used as a component of a thrust reverser, formed of at least one one-piece bondment cured in a single operation. Preferably, a one-piece inner bondment and a one-piece outer bondment fastened together at a joining region. The bondments have constant density cores and tapered closures. Acoustically absorbing materials are part of the lay up for one of the bondments and are integrally cured therein.

Abstract: A quiet nacelle system for jet aircraft engines includes a nose cowl and nose dome having a sound-attenuating liner, a concentric ring between the nose cowl and nose dome, and fan duct components having a sound-attenuating liner. The system is particularly suitable for JT3D-3B and JT3D-7 engines for use with DC-8 aircraft. The components may be combined as a hush kit for retrofit in existing nacelle systems.

Abstract: A boundary layer control device is installed in the acoustically treated inlet duct of a turbofan engine. The device sucks off the turbulent boundary layer of air flowing over the inner or "air wetted" surface of the inlet during aircraft take-off, cruise and approach. The lip of the inlet can thus be made thinner to reduce drag during cruise without degradation of fan performance during take-off. The acoustic liner of the inlet comprises a microporous honeycomb sandwich structure through which air may be sucked at various locations through headers and conduits connected to an onboard pump.

Abstract: The device is an air intake apparatus for a chain saw. There is a hollow main casing having front and rear ends. A handle extends above the casing. The handle is fixed to the casing. An engine is disposed in the casing. A carburator is disposed in the casing front adjacent to a fuel tank. An oil tank is disposed at the casing rear.

Abstract: A quiet nacelle system for jet aircraft engines includes an elongated nose cowl and nose dome of the nacelle and a sound-attenuating liner applied to the nose cowl, nose dome and fan duct components. The system is particularly suitable for JT3D-3B and JT3D-7 engines for use with DC-8 aircraft. The components may be combined as a hush kit for retrofit in existing nacelle systems.

Abstract: A nacelle structure (14) for a gas turbine engine (4) extends upstream from the engine air inlet (10) and includes an external surface (18) and an internal surface (16). The external surface (18) is concentric about a linear centerline (22) which is disposed parallel to the free airflow stream (6) encountered by the nacelle (14) in flight. The internal surface (16) is concentric about a curved centerline (30), the curved centerline (30) being parallel to the free airflow stream (6) at the nacelle inlet (12) and parallel to the engine centerline (26) at the engine air inlet (10) for smoothly directing the internal airflow stream (32) into the engine air inlet (10).

Abstract: A blower for an air spray bath massaging apparatus, which blower is operated by an electric motor and is enclosed in a housing having a suction air fitting and a compressed air fitting. To effectively reduce the suction noise of the blower, the suction air fitting is provided with a closure wall having a plurality of suction sleeves with suction inlets. The suction air current is divided into several smaller air currents by which considerably less suction noise is generated.

Abstract: The invention provides a silencer for high velocity gas flow which includes a flow passage 2 and a domed, perforated plate 1 which terminates the flow passage, wherein the perforated portions 9 of the plate are distributed over the plate so as to direct gas from the passage as plurality of divergent jets 7 whereby noise is produced with a frequency at maximum intensity in a range of the audible spectrum at which human auditory perception is relatively insensitive. Such a silencer may be used to reduce the perceived noise emitted by a gas turbine engine when for reasons of engine handling and response excess air bled from the compressor stages.

Abstract: In a jet engine in which the engine cowling includes an inlet cowl and an engine containment case and in which at least a portion of the interior surface of the inlet cowl is covered by an acoustic treatment material, a system for attaching the inlet cowl to the engine containment case icludes an attachment ring that is substantially U-shaped in cross section having a web and first and second legs extending orthogonally from the web. The first leg abuts an engine flange that is a part of the engine containment case. The first leg and engine flange are secured to one another by threaded fasteners. The web is attached to the acoustic treatment material by fasteners that pass through the web and the acoustic treatment material. The acoustic treatment material is effective up to the interface between the inlet cowl and the engine containment case.

Abstract: An annular groove formed on the inner surface of the porous sheet of an acoustical aircraft or jet engine liner spaced from the front edge and adjacent to the adhesive bonding material serves to prevent dislodgement of the entire porous sheet upon an impending peeling of the porous sheet. The groove also serves as a circuitous path for cracks propagating upstream from a fault manifested downstream therefrom.