ACOUSTIC PANEL AND METHOD FOR MAKING THE SAME

An acoustic panel comprises a face sheet comprising a plurality of openings; a back sheet opposite to the face sheet; and an intermediate layer comprising a plurality of cells each comprising a cavity and a plurality of walls extending between the face sheet and the back sheet and surrounding the cavity. The plurality of walls can comprise at least one and possibly a plurality of slots for drainage. A method for making the acoustic panel is also described.

BACKGROUND

The present embodiments generally relate to an acoustic panel and a method for making the acoustic panel. More particularly, the embodiments relate to an acoustic panel useful for acoustic or noise abatement purposes. For example acoustic or noise abatement purposes include, but are not limited to, turbomachinery, such as but not limited to, an engine and a method for making the acoustic panel.

To prevent a damage from, for example, a freeze-thaw cycle, acoustic panels may typically include slots to drain liquid. The liquid can be water and/or fuel, either for use with the device having the panels or from an exterior source from the device. In some instances, about 30% of the area of the acoustic panel can be provided with drainage slots.

However, drainage slots in the acoustic panel may have a negative effect on the desired acoustic or noise attenuation. These slots may reduce the acoustic or noise attenuation when the acoustic panel has a large amount of drainage slots that create “openings” which may not abate acoustics or noises in the device.

In addition, acoustic panel drainage slots may be provided in a default or standard pattern. These default patterns may not be able to support drainage.

BRIEF DESCRIPTION

In one aspect, embodiments of the present embodiment relate to an acoustic panel comprising: a face sheet comprising a plurality of openings; a back sheet opposite to the face sheet; and an intermediate layer comprising a plurality of cells each comprising a cavity and a plurality of walls extending between the face sheet and the back sheet and surrounding the cavity, the plurality of walls being provided by additive manufacturing and comprising a plurality of slots all supporting drainage of liquid.

In another aspect, embodiments of the present embodiment relate to a method for making an acoustic panel, comprising: providing a face sheet comprising a plurality of openings; providing a back sheet opposite to the face sheet; and providing an intermediate layer comprising a plurality of cells each comprising a cavity and a plurality of walls extending between the face sheet and the back sheet and surrounding the cavity, the plurality of walls being provided by additive manufacturing and comprising a plurality of slots all supporting drainage of liquid.

Optionally, the acoustic panel is useful in an engine. Optionally, the acoustic panel is useful in an aero engine. Optionally, the acoustic panel is useful in an aircraft engine. Optionally, the plurality of cavities is in fluid communication with the plurality of openings. Optionally, the plurality of slots comprises a plurality of sets of slots and the slots in each of the plurality of sets of slots are in fluid communication with each other and are aligned with a direction of the drainage of the liquid. Optionally, the slots in each of the plurality of sets of slots are aligned substantially parallel with the direction of the drainage of the liquid. Optionally, one of the plurality of cells comprises two slots in corresponding walls thereof. Optionally, one of the plurality of cells comprises at least two slots in corresponding walls thereof. Optionally, one of the plurality of cells has a cross-section of a polygon.

Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of this embodiment. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of this embodiment. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.

DETAILED DESCRIPTION

As used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations that extend arcuately about the centerline of the engine.

The term “coupled”, or “connected”, as used herein, is defined as coupled, or connected, directly or indirectly.

Embodiments herein relate to acoustic panels for acoustic or noise abatement purposes. Acoustic panels find exemplary and non-limiting applications where sound quality improvement and/or abatement are desirable. For example, and in no way limiting of the embodiments, acoustic panels may be used in offices, recording studies, homes, theaters, museums, restaurants, and other facilities where acoustics, noise quality and levels are a concern.

Moreover, and in no way limiting of the embodiments, acoustic panels may be used on or in machines where acoustics and noise abatement are needed or desired. These applications may include but are not limited to, manufacturing machinery, cooling and heating devices, and powerplants including those with turbomachinery, such as gas turbines, steam turbines, generators, and reciprocating engines. Acoustic panels are often useful to manage acoustics and sound quality on turbomachines, such as aero turbomachines and/or aircraft engines.

Moreover, the acoustic panels described herein comprise slots for drainage of liquid, such as water and/or fuel. The liquid may be present in the panels from openings in a face sheet of the panel. These openings are provided to facilitate drainage of liquid that is used in the operation of the device, or originates outside of the device. Regardless of the source of the liquid in the panel, the slots permit drainage of the liquid therefrom. Additionally, the slots in the acoustic panels can be provided during manufacture of the panels. The manufacturing of the panels and the formation of the slots can be by any suitable process, such as but not limited to, machining, additive manufacturing, 3D printing, forming during the molding or assembly.

The configuration of the acoustic panel herein can facilitate reduction of attenuation therein by reducing the number of slots in the acoustic panel. For example, slots that do not drain liquid can be eliminated. Additionally, the s acoustic panel configuration and the method for making the acoustic panel can increase the attenuation of the acoustic panel, increasing noise margins. Thus, it is possible to achieve desired noise levels with an acoustic panel having a reduced acoustic area and/or length, shorter duct lengths, lighter nacelle, reduced scrubbing drag, and/or lower cost, among other benefits, compared to other panels.

As used herein, the terms “face”, “back”, “intermediate”, “front”, “forward”, “aft”, “upper”, “lower”, etc., may be used in reference to the perspective of the installation and orientation of the components in the drawings, and therefore are relative terms that indicate the construction, installation and use of the components. However, it is within the scope of the embodiment that the components could be installed and/or used that markedly differs from the components shown in the drawings, or installed at other points of the engine.

The acoustic panel21, as embodied herein will be described with respect toFIGS. 2 and 3.FIG. 1illustrates one exemplary and non-limiting application of the acoustic panel as per the embodiments herein, for example and in no way limiting in turbomachine, such as an engine.FIG. 1application is merely exemplary, and other applications are within the scope of this instant application and claims.

FIG. 1is a cross-sectional schematic illustration of an exemplary gas turbine engine assembly110having a longitudinal axis111. Gas turbine engine assembly110includes a fan assembly112and a core gas turbine engine113. Core gas turbine engine113includes a high-pressure compressor114, a combustor116, and a high-pressure turbine118. In the exemplary embodiment, gas turbine engine assembly110also includes a low-pressure turbine120, and a multi-stage booster compressor122, and a splitter144that substantially circumscribes booster122.

Fan assembly112includes an array of fan blades124extending radially outward from a rotor disk126. Gas turbine engine assembly110has an intake side128and an exhaust side130. Fan assembly112, booster122, and turbine120are coupled together by a first rotor shaft131, and compressor114and turbine118are coupled together by a second rotor shaft132.

In operation, air flows through fan assembly112and a first portion150of the airflow is channeled through booster122. The compressed air that is discharged from booster122is channeled through compressor114wherein the airflow is further compressed and delivered to combustor116. Hot products of combustion (not shown inFIG. 1) from combustor116are utilized to drive turbines118and120, and turbine120is utilized to drive fan assembly112and booster122by way of shaft131. Gas turbine engine assembly110is operable at a range of operating conditions between design operating conditions and off-design operating conditions.

A second portion152of the airflow discharged from fan assembly112is channeled through a bypass duct140to bypass a portion of the airflow from fan assembly112around the core gas turbine engine113. More specifically, bypass duct140extends between a fan casing142and splitter144. Accordingly, a first portion150of the airflow from fan assembly112is channeled through booster122and then into compressor114as described above and a second portion152of the airflow from fan assembly112is channeled through bypass duct140to provide thrust for an aircraft, for example. Gas turbine engine assembly110also includes a fan frame assembly160to provide structural support for fan assembly112and is also utilized to couple fan assembly112to core gas turbine engine113.

Fan frame assembly160includes a plurality of outlet guide vanes170that typically extend substantially radially, between a radially-outer mounting flange and a radially-inner mounting flange, and are circumferentially-spaced within bypass duct140. Guide vanes170serve to turn the airflow downstream from rotating blades such as fan blades124.

To reduce noise emanating anywhere in the engine110, such as but not limited to, in the overall fan frame assembly160, portions thereof may be lined with noise attenuation panels, which are in the form of an acoustic panel21, as per the embodiments herein and described with reference toFIGS. 2 and 3. As shown inFIG. 1, the engine110may have its fan frame assembly160lined with the acoustic panels at but not limited to one or more of regions proximate the fan duct, a thrust reversal unit, the inner wall of the its fan frame assembly160and/or the inner fan duct wall.

The acoustic panel21can be applied anywhere in the engine where noise attenuation is needed. The acoustic panel21can be configured in an arcuate form, for example, having a double curvature configuration. This configuration is embodied in structural parts of the engine110illustrated inFIG. 1. In some embodiments, the acoustic panel21may be also placed directly on the inner and outer surfaces of the inner and outer walls of the primary nozzle (not illustrated), and/or on the bifurcations (areas where the acoustic panel21are located inFIG. 1). The acoustic panel21may be a single feature or provided in combination extending circumferentially around the nacelle structure113.

Referring now toFIGS. 2 and 3, a noise attenuation or acoustic panel21is illustrated. The acoustic panel21illustrated comprises a face sheet22comprising a plurality of openings23, a back sheet24opposite to the face sheet22, and a cellular intermediate layer25comprising a plurality of cells26. Each cell26comprises a cavity260and a plurality of walls261extending between the face sheet22and the back sheet24and surrounding the cavity260. The plurality of walls261can be provided by any appropriate manufacturing process in the formation of the acoustic panel21. One such non-limiting manufacturing process is additive manufacturing. The plurality of walls comprises a plurality of slots262, through which liquids can drain, as described hereinafter.

The plurality of openings23in the face sheet23provide fluid communication between the cells26of the cellular intermediate layer25and the front face of the face sheet22. Fluid can pass through one or more of the plurality of openings23in the face sheet22and enter into the cells26of the cellular intermediate layer25.

The plurality of openings23of the face sheet22of the acoustic panel21have any cross-section (such as the circular cross-section as illustrated inFIG. 2), and can be formed with uniform or non-uniform sizes over the surface of the face sheet22. Also, the plurality of openings23of the face sheet22of the acoustic panel21can be uniformly or non-uniformly distributed over the surface of the face sheet22.

To provide for noise attenuation over a wide range of frequencies, the geometry and distribution of one or more of the plurality of openings23may be modified. For example and not limiting of the embodiments, one or more of the plurality of openings23may be positioned as an array of openings, and with an opening size and shape that vary over the face sheet22. An opening size variation may provide differentiated attenuating performance across the acoustic panel21.

The plurality of openings23may be produced by any appropriate manufacturing process. Exemplary and non-limiting processes include at least one of additive manufacturing, 3D printing, mechanical drilling, laser beam drilling, and/or electron beam drilling. The plurality of openings23may be produced prior to the face sheet22, the cellular intermediate layer25and the back sheet24are joined. However, depending on the manufacturing process, the formation of the plurality of openings may at any appropriate.

The face sheet22is coupled to an upper face of the cellular intermediate layer25. The coupling can be by an adhesive, by the manufacturing processing or other suitable coupling system. The back sheet24may be unperforated and made from an impermeable sheet material. The back sheet24may also be connected by be by an adhesive, by the manufacturing processing or other suitable coupling system to a lower face of the cellular intermediate layer25. The cells26of the cellular intermediate layer25are open-ended and juxtaposed. Also, the plurality of cavities260defined thereby may be in fluid communication with the plurality of openings23, as illustrated inFIG. 2by arrows X.

In other exemplary non-limiting embodiments, one or more of the plurality of cells26may have a polygonal cross-section264. For example, and not intending to limit the embodiments in any way, one or more of the plurality of cells26may have hexagonal cross sections to provide a honeycomb configuration of the intermediate layer25. Alternatively, the one or more of the plurality of cells26may have juxtaposed cells of other polygonal cross-sections other than but including hexagonal positioned in the acoustic panel, with cells of different sizes and shapes adjacent each other. For example, one or more of the plurality of cells26may be rectangular, one or more of the plurality of cells26may be triangular, one or more of the plurality of cells26may be hexagonal, one or more of the plurality of cells26may be octagonal, and so forth. In essence, the configuration and polygonal shapes of the one or more of the plurality of cells26can take numerous and non-limiting shapes, arrangements, and formations.

In a non-limiting embodiment, the slots262in the walls261can allow fluids, such as water and/or fuel, to drain from the acoustic panel21, in the direction of arrows Y. Following the fluid flow, the fluid enters the acoustic panel21through the plurality of holes23in the face sheet22, as shown by arrow X. As the fluid enters the intermediate layer25it enters one of the plurality of cells26. From that cell26to which the fluid enters, it can then flow through slots262as illustrated inFIG. 2. As illustrated, the slots262can be arranged flow fluid from one cell262to another cell26, while the flow can continue in the direction of arrows Y to drain the fluid out of the acoustic panel21. Some of the cells26may comprise only one slot262where that cell is proximate a terminus edge of the acoustic panel21, so as the fluid flow (Arrow X′) needs to only flow into one cell26to exit a slot262to the outside of the acoustic panel21. Others of the cells26may comprise two slots, thus fluid may enter the cell26from one slot262at one side of the cell26and exit the cell26from the other side's slot262. This fluid flow is best illustrated at arrow Y at the right side of the acoustic panel21inFIG. 2. Also, as desired and necessitated by the acoustic panel21configuration, more than two slots262may be provided in a cell26depending on the orientation of the acoustic panel21and the desired direction of the fluid flow from the acoustic panel21.

As illustrated inFIG. 3, which is a top view of a plurality of cells26in the intermediate layer25, the plurality of slots262may comprise a plurality of slot sets (hereinafter “sets of slots”)263. The slots262in each of the plurality of sets of slots263are in fluid communication with each other. These plurality of sets of slots263can be aligned in a direction D of the drainage of the liquid. In some embodiments, the slots262in each of the plurality of sets of slots263are directedly aligned with the direction D of the drainage of the liquid.

Alternatively, the plurality of sets of slots263can be aligned with line S, which connects slots262of two adjacent cells26in one set of slots263. Line S defines an acute angle α with respect to the direction D of the drainage of the liquid.

Referring toFIG. 4a method40for making an acoustic panel21. The exemplary method comprises Step41, providing/forming a face sheet22comprising a plurality of openings; Step42, providing/forming a back sheet opposite to the face sheet22; and Step43, providing/forming an intermediate layer25, where the intermediate layer25comprises a plurality of cells26each comprising a cavity and a plurality of walls extending between the face sheet22and the back sheet24and surrounding the cavity26. The plurality of walls comprising a plurality of slots262for drainage of fluid from the cells26. In Step44the face sheet22, the back sheet24, and the intermediate layer25are joined to form the acoustic panel21.

In an alternate method, Steps41,42and43may be simultaneously provided/formed in a contemporaneously to form the acoustic panel21. Exemplary simultaneous methods include, but are not limited to, forming the acoustic panel21by molding, 3D printing, additive manufacturing, and the similar simultaneous manufacturing processes.