Patent Application
20210071547
The present disclosure relates generally to high temperature exhaust systems and particularly to dampers used with high temperature exhaust systems. More particularly, the present disclosure relates to exhaust ducts and damper systems for use with gas turbine engines.
Gas turbine engines and other engines typically combust fuel during operation. The combustion process produces hot exhaust gases which may be directed away from the gas turbine engine through one or more exhaust ducts. The exhaust gases may cause the exhaust duct to vibrate and produce noises. Some exhaust ducts may include stiffening structures to strengthen the exhaust duct to reduce vibrations and noise. However, these features may use time and costs to design the exhaust duct as well as added materials.
The present disclosure may comprise one or more of the following features and combinations thereof.
According to one aspect of the present disclosure, an exhaust assembly for use with a gas turbine engine includes an exhaust duct, and a damper system. The exhaust duct is configured for fluid communication with the gas turbine engine to receive hot exhaust gases produced by the gas turbine engine. a damper system configured to dampen vibration of the exhaust duct during use of the gas turbine engine.
In some embodiments, the exhaust duct includes a plurality of panels that define an exhaust passageway. A first panel included in the plurality of panels includes a flat inner surface that faces toward the exhaust passageway, a flat outer surface opposite the flat inner surface, and an outer edge that extends around the first panel. The first panel is supported only along the outer edge.
In some embodiments, the damper system includes a fabric damper sheet, a rigid damper plate, and a damper bracket. The fabric damper sheet is engaged with the flat outer surface of the first panel. The rigid damper plate is arranged in face-to-face relation with the fabric damper sheet and spaced apart from the first panel to locate the fabric damper sheet between the damper plate and the first panel. The damper plate has a body and a perimeter edge arranged around the body.
In some embodiments, the damper bracket has a frame that extends along the perimeter edge of the damper plate and defines a window that opens through the damper bracket to expose the body of the damper plate. The damper bracket is coupled with the first panel and engaged with the perimeter edge of the damper plate to change a resonance frequency of the exhaust duct and dampen the vibration of the exhaust duct during use of the gas turbine engine.
In some embodiments, the damper plate is coupled to the damper bracket by friction only. In some embodiments, the fabric damper sheet comprises non-viscoelastic material.
In some embodiments, the frame of the damper bracket includes an attachment segment with an inner surface coupled to the first panel and a clip segment with an inner surface engaged with the damper plate. The clip segment is offset from the attachment segment and arranged generally parallel with the attachment segment.
In some embodiments, the clip segment is spaced apart from the damper plate to define a damper cavity between the clip segment and the first panel. A distance from the inner surface of the clip segment to the first panel is less than a cumulative thickness of the damper plate and the fabric damper sheet.
In some embodiments, the frame further includes a link that extends outwardly away from the first panel at an angle relative to the first panel to interconnect the attachment segment and the clip segment.
In some embodiments, the frame of the damper bracket includes an attachment segment with an inner surface coupled to the first panel, a clip segment with an inner surface engaged with the damper plate, and a link that extends outwardly away from the first panel at an angle relative to the first panel to interconnect the attachment segment to the clip segment. The clip segment extends downwardly from the link at an angle toward the damper plate and is configured to apply a compressive force on the damper plate when the frame is fully installed on the first panel.
In some embodiments, the damper bracket further includes a cross member that extends across the window of the frame to divide the window into a first aperture and a second aperture. The damper bracket may further include a stiffening rib coupled with the cross member to reinforce the cross member and the frame.
According to another aspect of the present disclosure, the damper system includes a damper, a damper plate, and a damper bracket. The damper may be coupled with the flat outer surface of the first panel. The damper plate is arranged in face-to-face relation with the damper and spaced apart from the first panel to locate the damper between the damper plate and the first panel. The damper plate has a body and a perimeter edge arranged around the body. The damper bracket is coupled with the first panel and engaged with the damper plate to change a resonance frequency of the exhaust duct and dampen the vibration of the exhaust duct during use of the gas turbine engine.
In some embodiments, the damper includes a fabric damper sheet made from non-viscoelastic material positioned between the damper plate and the first panel.
In some embodiments, an air gap is defined between the damper plate and the first panel to provide the damper.
In some embodiments, the damper bracket includes a plurality of washers coupled with an outer surface of the damper plate and a plurality of fasteners that extend through apertures formed in the damper plate and the first panel, the plurality of washers configured to clamp the damper plate and the damper between the plurality of washers and the first panel.
According to another aspect of the present disclosure, a method includes: providing an exhaust duct formed from a plurality of panels with inner surfaces defining an exhaust passageway and outer surfaces facing away from the exhaust passageway; discharging exhaust gases through the exhaust passageway to cause at least one of the panels to vibrate and produce noise and to expose the at least one panel to temperatures greater than about 250 degrees Fahrenheit; and changing a resonance frequency of the at least one panel by coupling a fabric damper sheet to the outer surface of the at least one panel to reduce vibrations and noise.
In some embodiments, the step of changing the resonance frequency of the at least one panel includes applying a rigid damper plate over the fabric damper sheet to locate the fabric damper sheet between the damper plate and the at least one panel.
In some embodiments, the step of changing a resonance frequency of the at least one panel further includes clamping the damper plate and the fabric damper sheet to the at least one panel with a damper bracket that has a frame disposed around a perimeter of the damper plate and defines a window that opens to expose the damper plate.
In some embodiments, the step of changing a resonance frequency of the at least one panel further includes clamping the damper plate and the fabric damper sheet to the at least one panel with a plurality of washers and corresponding fasteners, the plurality of washers disposed along an outer surface of the damper plate.
These and other features of the present disclosure will become more apparent from the following description of the illustrative embodiments.
For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to a number of illustrative embodiments illustrated in the drawings and specific language will be used to describe the same.
In accordance with the present disclosure, a power generation facility 10 includes an engine 12, a generator 14, and an exhaust assembly 16 coupled with the engine 12 as shown in
In the illustrative embodiment, the engine 12 includes a gas turbine engine; however in other embodiments any combustion engine may be used. The gas turbine engine is shown diagrammatically in
The exhaust assembly 16 includes an exhaust duct 28 and a damper system 30 coupled to the exhaust duct 28 and configured to dampen vibration of the exhaust duct 28 during use of the gas turbine engine 12 as shown in
The exhaust duct 28 includes a plurality of panels 32 that define an exhaust passageway 34. Each of the plurality of panels 32 is made from sheet metal and may vibrate and produce noise as the hot exhaust gases flow through the exhaust passageway 34. The plurality of panels 32 may be integrally formed or formed from independent panel sections that are coupled together via fasteners, welding, brazing, etc. The damper system 30 is coupled to at least one of the panels 32 as shown in
A first panel 36 included in the plurality of panels 32 includes a flat inner surface 38 that faces toward the exhaust passageway 34, a flat outer surface 40 opposite the flat inner surface 38, and an outer edge 42 that extends around the first panel 36 as shown in
The plurality of panels 32 are unsupported along their inner surfaces and outer surfaces. In other words, the panels 32 like a simply supported beam; the panels 32 are supported at their edges, but are not supported in their midsections (by struts or any other support feature). Other panels that are used to form exhaust ducts are designed with structures that reinforce each panels to reduce vibrations and noise. The panels in the illustrative embodiment are formed without any reinforcement structures to reduce an amount of material used to construct the exhaust duct 28 and minimize time and cost that would ordinarily be spent designing each of the panels 32 in a way which reinforces the panels 32.
Vibrations and noise are reduced in the illustrative embodiment by providing the damper system 30 on one or more of the panels 32 as shown in
The fabric damper sheet 44 is made from a material that is able to withstand high temperatures caused by the hot exhaust gases flowing through the exhaust passageway 34. Some friction dampers include a viscoelastic material, such as rubber, for example, which fail when exposed to elevated temperatures (i.e. greater than 250 degrees Fahrenheit). In the illustrative embodiment, the fabric damper sheet 44 is made from only non-viscoelastic materials and is capable of withstanding temperatures greater than at least 250 degrees Fahrenheit. One non-limiting example of a suitable sheet is NEXTEL™ produced by 3M Manufacturing Company; however any suitable non-viscoelastic material may be used.
The damper plate 46 includes a body 50 and a perimeter edge 52 arranged around the body 50 as shown in
The damper bracket 48 includes a frame 54 that at least partially extends along the perimeter edge 52 of the damper plate 46 and retention means for coupling the damper plate 46 to the first panel 36 as shown in
The frame 54 of the damper bracket 48 is configured to provide a force on the damper plate 46 that increases a coefficient of friction of the fabric damper sheet 44 relative to the outer surface 40 of the first panel 36. The frame 54 includes an attachment segment 56, a clip segment 58, and a link 60 interconnecting the attachment segment 56 and the clip segment 58 as shown in
The clip segment 58 is offset from the attachment segment 56 relative to the first panel 36 and arranged generally parallel with the attachment segment 56. The clip segment 58 is spaced apart from the damper plate 46 to define a damper cavity 66 between the clip segment 58 and the first panel 36. Prior to installation, the clip segment 58 of the frame 54 may be arranged at a position 68 indicated by the dashed lines in
When the damper bracket 48 is installed, the clip segment 58 engages the damper plate 46 and flexes upwardly relative to the attachment segment 56 due to the size differences between distance 70 and thickness 72. In the flexed position, the clip segment 58 provides a compressive force on the damper plate 46 to increase a coefficient of friction between the damper plate 46 and the fabric damper sheet 44 and between the fabric damper sheet 44 and the first panel 36.
The retention means in the illustrative embodiment includes a fastener 74 and a nut 76 as shown in
Another embodiment of a damper bracket 248 is shown in
The damper bracket 248 includes a frame 254 and retention means as shown in
The clip segment 258 extends downwardly from the link 260 at an angle relative to the first panel toward the damper plate 46 as shown in
Another embodiment of a damper bracket 348 is shown in
The damper bracket 348 includes a frame 354 and retention means as shown in
The retention means in the illustrative embodiment includes a first fastener 374 and a second fastener 382 as shown in
Another embodiment of a damper system 430 is shown in
Each of the fasteners 456 extend through apertures 458, 459, 460 formed in the damper plate 46, the fabric damper sheet 44, and the first panel 36, respectively, as shown in
Another embodiment of a damper system 530 is shown in
The frame 554 is formed to include a window 555. The cross member 559 extends across the window 555 of the frame 554 and divides the window 555 into a first aperture 561 and a second aperture 563. The cross member 559 is configured to reinforce the frame 554 and provide more support for the damper plate 46. In the illustrative embodiment, the damper bracket 548 further includes a second cross member 565 arranged perpendicular to the cross member 559. The cross member 559 and the second cross member 565 cooperate with the frame to divide the window 555 into four apertures.
In the illustrative embodiment, the damper bracket 548 may further include a stiffening rib 567 coupled with an outer surface 569 of one or both of the cross members 559, 565. The stiffening rib 567 is configured to reinforce the cross member 559 which further reinforces the frame 554 and provides more support for the damper plate 46. In illustrative embodiments, the stiffening rib 567 is integral with the damper bracket 548 such that they form a single unitary component. The sheet metal of the damper bracket 548 maybe bent or formed to provide the stiffening rib 567.
Another embodiment of a damper system 630 is shown in
In some embodiments, large panels exposed to aero-acoustic excitation may exhibit damaging resonance at one or more frequencies experienced within the component's operating envelope. In the past, if these damaging resonances were predicted or experienced during testing, the natural tendency of a designer was to add stiffening features to the component panels for purposes of driving the damaging resonance outside of the operating envelope.
In some embodiments, the ability to redesign the system to include stiffening features may not be an option. Typical viscoelastic dampening sheets may not be a viable option given there limited temperature capability. The damper system in accordance with the present disclosure may reduce damaging resonance of the ejector panels at elevated temperatures. The damper system may be installed in several locations on unsupported panels on an exhaust ejector, or duct. The damper system may also be used on any large unsupported panel exposed to aero-acoustic excitation.
In some embodiments, plates may be placed on the large unsupported panels within an ejector or duct. These plates may or may not trap a high temperature fabric layer (e.g. NEXTEL™ cloth) between the plate and the unsupported panel. The plates are held in place with a picture frame like structure which may or may not impose a preload on the plate/fabric layer utilizing fender and/or Bellville washers. The combination of these components results in a frictional damper whereby friction is created between the fabric layer and unsupported panel as well as between the fabric layer and the attached plate.
In some embodiments, the high temperature damper can be used in applications in which aero-acoustic vibration causes panels to be excited. Prior damping technologies utilize visco-elastic material such as rubber adhered to the back of a metallic or fiber-reinforced panel and therefore may only withstand temperatures as high as about 250 degrees Fahrenheit. The present disclosure uses a high temperature fabric, such as NEXTEL™, which allows the frictional component to withstand significantly higher temperatures and last longer than other viscoelastic dampers.
While the disclosure has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.
