The subject matter disclosed herein generally relates to gas turbine engines and, more particularly, to borescope plugs for gas turbine engines.
Borescope inspection ports can be used on gas turbine engines to enable and allow visual inspection of internal aircraft engine flowpath hardware with a fiber optic borescope. These borescope ports thereby make possible frequent critical engine inspections that otherwise could not be performed without disassembly of the aircraft engine. As such, borescope ports and attendant inspections can allow increased engine usage between overhaul and thus lowers aircraft engine operating costs. A borescope port is plugged by a borescope plug during operation of the aircraft engine. The borescope plug can be subject to high stresses at a shank of the borescope plug which can lead to decreased life of the borescope plug.
Accordingly, it may be advantageous to provide improved life borescope plugs.
According to some embodiments, borescope plugs are provided. The borescope plugs include a borescope plug base having a first side configured to support a shank and a second side having a centroid defined as the center of the borescope plug base, a first mounting aperture formed in the second side, and a second mounting aperture formed in the second side. The first and second mounting apertures are configured to each receive a fastener to mount the borescope plug base to a case and an offset line drawn through the center of the first mounting aperture and through the center of the second mounting aperture does not pass through the centroid or does not include a point defined by the centroid.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the borescope plug base is at least one of square shaped, rectangular shaped, circular shaped, triangular shaped, and polygon shaped.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the offset line has an offset from the centroid being a shortest distance between the offset line and the centroid.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the offset is 1/10 inch or less (0.254 cm or less).
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include a boss on the first side of the borescope plug.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the boss defines a base cavity.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include a first anti-rotation element arranged within the base cavity, the first anti-rotation element configured to be received within a second first anti-rotation element of a shank that is installed to the borescope plug base.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the first anti-rotation element is a pin.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the boss is aligned with the centroid.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include a shank extending from the boss.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the shank is integrally formed with the boss.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the shank includes a base engagement element at a first end of the shank and a plug member located at a second end of the shank, the plug member configured to plug a borescope aperture in a borescope vane cluster, wherein the base engagement element fits within a base cavity such that the base moveably retains the base engagement element and wherein the base engagement element can move within the base cavity.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include a first anti-rotation element arranged within a base cavity of the borescope plug base and a second anti-rotation element arranged as part of the base engagement element. The first anti-rotation element is configured to be received within the second anti-rotation element.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the first anti-rotation element is positioned within the base cavity relative to the shank such that the position of the first anti-rotation element is aligned with an outer surface or an outer radius of the shank.
According to some embodiments, borescope plugs are described. The borescope plugs include a borescope plug base having a first side configured to support a shank and a second side having a major axis and a minor axis passing through a center of the second side of the borescope plug base, a first mounting aperture formed in the second side, and a second mounting aperture formed in the second side. The first and second mounting apertures are configured to each receive a fastener to mount the borescope plug base to a case and the first mounting aperture is positioned an offset distance from the major axis and the first and second mounting apertures are not symmetric about the minor axis.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include a first anti-rotation element arranged within on the first side of the borescope plug base, the first anti-rotation element configured to be received within a second first anti-rotation element of a shank that is installed to the borescope plug base, wherein the first anti-rotation element is a pin.
In addition to one or more of the features described above, or as an alternative, further embodiments of the borescope plugs may include that the offset distance is 1/10 inch or less (0.254 cm or less).
According to some embodiments, gas turbine engines are provided. The gas turbine engines include a case having a case aperture, a borescope vane cluster installed on an inner diameter of the case proximate the case aperture and having a borescope aperture and a borescope plug. The borescope plug includes a base fixedly attached to the case and having a first side and a second side, the second side having a centroid defined as the center of the borescope plug base, a first mounting aperture formed in the second side, and a second mounting aperture formed in the second side. The first and second mounting apertures are configured to each receive a fastener to mount the borescope plug base to the case and an offset line drawn through the center of the first mounting aperture and through the center of the second mounting aperture does not pass through the centroid or does not include a point defined by the centroid.
In addition to one or more of the features described above, or as an alternative, further embodiments of the gas turbine engines may include that a boss formed on the first side of the base and a shank extending from the boss. The shank includes a base engagement element at a first end of the shank and a plug member located at a second end of the shank, the plug member configured to plug a borescope aperture in a borescope vane cluster, wherein the base engagement element fits within a base cavity such that the base moveably retains the base engagement element and wherein the base engagement element can move within the base cavity.
In addition to one or more of the features described above, or as an alternative, further embodiments of the gas turbine engines may include a first anti-rotation element arranged within the base cavity and a second anti-rotation element arranged as part of the base engagement element. The first anti-rotation element is a pin and is configured to be received within the second anti-rotation element.
The foregoing features and elements may be executed or utilized in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.
The subject matter is particularly pointed out and distinctly claimed at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The gas turbine engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine centerline longitudinal axis A. The low speed spool 30 and the high speed spool 32 may be mounted relative to an engine static structure 33 via several bearing systems 31. It should be understood that other bearing systems 31 may alternatively or additionally be provided.
The low speed spool 30 generally includes an inner shaft 34 that interconnects a fan 36, a low pressure compressor 38 and a low pressure turbine 39. The inner shaft 34 can be connected to the fan 36 through a geared architecture 45 to drive the fan 36 at a lower speed than the low speed spool 30. The high speed spool 32 includes an outer shaft 35 that interconnects a high pressure compressor 37 and a high pressure turbine 40. In this embodiment, the inner shaft 34 and the outer shaft 35 are supported at various axial locations by bearing systems 31 positioned within the engine static structure 33.
A combustor 42 is arranged between the high pressure compressor 37 and the high pressure turbine 40. A mid-turbine frame 44 may be arranged generally between the high pressure turbine 40 and the low pressure turbine 39. The mid-turbine frame 44 can support one or more bearing systems 31 of the turbine section 28. The mid-turbine frame 44 may include one or more airfoils 46 that extend within the core flow path C.
The inner shaft 34 and the outer shaft 35 are concentric and rotate via the bearing systems 31 about the engine centerline longitudinal axis As which is co-linear with their longitudinal axes. The core airflow is compressed by the low pressure compressor 38 and the high pressure compressor 37, is mixed with fuel and burned in the combustor 42, and is then expanded over the high pressure turbine 40 and the low pressure turbine 39. The high pressure turbine 40 and the low pressure turbine 39 rotationally drive the respective high speed spool 32 and the low speed spool 30 in response to the expansion.
The pressure ratio of the low pressure turbine 39 can be pressure measured prior to the inlet of the low pressure turbine 39 as related to the pressure at the outlet of the low pressure turbine 39 and prior to an exhaust nozzle of the gas turbine engine 20. A bypass ratio (BPR) of a gas turbine engine is the ratio between the mass flow rate of air drawn through the fan disk that bypasses the engine core (un-combusted air) to the mass flow rate passing through the engine core (combusted air). For example, a 10:1 bypass ratio means that 10 kg of air passes around the core for every 1 kg of air passing through the core. In one non-limiting embodiment, the bypass ratio of the gas turbine engine 20 is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor 38, and the low pressure turbine 39 has a pressure ratio that is greater than about five (5:1). It should be understood, however, that the above parameters are only examples of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines, including direct drive turbofans.
In this embodiment of the example gas turbine engine 20, a significant amount of thrust is provided by the bypass flow path B due to the high bypass ratio. The fan section 22 of the gas turbine engine 20 is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet. This flight condition, with the gas turbine engine 20 at its best fuel consumption, is also known as bucket cruise Thrust Specific Fuel Consumption (TSFC). TSFC is an industry standard parameter of fuel consumption per unit of thrust.
Each of the compressor section 24 and the turbine section 28 may include alternating rows of rotor assemblies and vane assemblies (shown schematically) that carry airfoils that extend into the core flow path C. For example, the rotor assemblies can carry a plurality of rotating blades 25, while each vane assembly can carry a plurality of vanes 27 that extend into the core flow path C. The blades 25 of the rotor assemblies add or extract energy from the core airflow that is communicated through the gas turbine engine 20 along the core flow path C. The vanes 27 of the vane assemblies direct the core airflow to the blades 25 to either add or extract energy.
Various components of a gas turbine engine 20, including but not limited to the airfoils of the blades 25 and the vanes 27 of the compressor section 24 and the turbine section 28, may be subjected to repetitive thermal cycling under widely ranging temperatures and pressures. The hardware of the turbine section 28 is particularly subjected to relatively extreme operating conditions. Therefore, some components may require internal cooling circuits for cooling the parts during engine operation. Example cooling circuits that include features such as airflow bleed ports are discussed below.
Although an example architecture for gas turbine engines is depicted (e.g., turbofan in
The turbine 200 is housed within a case 212, which may have multiple parts (e.g., turbine case, diffuser case, etc.). In various locations, components, such as seals, may be positioned between airfoils 201, 202 and the case 212. For example, as shown in
Turning now to
As shown in
During operation, the borescope plug 322 can be subject to high stresses at the shank 328. The shank 328 thus can have a limiting life cycle. The embodiment shown in
Turning now to
As shown, the borescope plug 422 includes a base 426, a shank 428, and a plug member 430. However, in contrast to the embodiment shown in
As shown in
As shown, the retainer 434 fits around a portion of the shank 428 and keeps the shank 428 and the base 426 together while allowing the shank 428 and plug member 430 to rotate about a plug axis Ap. The retainer 434 has a retainer aperture 442 that is wide enough to enable the shank 428 to pass therethrough and also enable movement of the shank 428 within the retainer aperture 442. However, the retainer aperture 442 has a smaller diameter or shape than a diameter or shape of the base engagement element 438. The base engagement element 438 fits within a base cavity 444 of the base 426 that is configured to receive the base engagement element 438. The base engagement element 438 is sized to be smaller than the base cavity 444 such that the shank 428 can rotate about the shank axis Ap.
Furthermore, the base engagement element 438 is sized such that movement of the base engagement element 438 within the base cavity 444 is possible. Accordingly, in addition to rotational movement about the shank axis Ap, the base engagement element 438 is enabled to move laterally or in a plane perpendicular to the shank axis Ap. That is, the base engagement element 438 can translate across a plane parallel to a surface of the base 426. Because the shank 428 can rotate, the plug member 430 is modified to have a round geometry such that the same shape of the plug member 430 always extends into a flow path of the borescope vane cluster 420 and the seal 436 prevents gas path air ingestion through the borescope aperture 424.
In some embodiments, the shape of the base of embodiments of the present disclosure may not be flat (e.g., as shown in the figures). That is, in some embodiments, the base may have a curved or other shape or contour such that the base does not define a plane. However, the base cavity in various embodiments can be sized and shaped to receive a base engagement element and allow for movement of the base engagement element within the base cavity. Thus, the illustrations presented herein are merely for illustrative and explanatory purposes and are not intended to be limiting.
Turning now to
Similar to that shown in
As described with respect to
In contrast, the shank 528 and plug member 530 of the embodiment of
As shown in
In the embodiment of
Turning now to
As shown, the borescope plug 622 includes a base 626, a shank 628, and a plug member 630. As shown, the base 626 and the shank 628 are separate components. Accordingly, the shank 628, and thus the plug member 630, can move relative to the base 626. The base 626 is fixedly attached or otherwise connected to the case 612 and the plug member 630 and shank 628 can move relative thereto.
As shown in
The shank 628 has a base engagement element 638 at a first end of the shank 628 and the plug member 630 is at a second (opposite) end of the shank 628. The shank 628 further includes an optional flange 632 (shown in
As shown, the integral retainer 634 defines the base cavity 644 fits around a portion of the shank 628 and keeps the shank 628 and the base 626 together while allowing the shank 628 and plug member 630 to rotate about a plug axis Ap. The retainer 634, as shown, includes crimping features or fingers that can be open to receive the base engagement element 638 of the shank 628 and then close about the base engagement element 638 to secure the shank 628 to the base 626. The integral retainer 634 is configured to enable movement of the base engagement element 638, and thus the shank 628, within the integral retainer 634. The base engagement element 438 is sized to be smaller than the base cavity 644 of the integral retainer 634 such that the shank 628 can rotate about the shank axis A.
Furthermore, the base engagement element 638 is sized such that movement of the base engagement element 638 within the base cavity 644 is possible. That is, for example, in addition to rotational movement about the shank axis As, the base engagement element 638 is enabled to move in a plane perpendicular to the shank axis A. Stated another way, the base engagement element 638 can translate across a plane parallel to a surface of the base 626. Because the shank 628 can rotate, the plug member 630 is modified to have a round geometry such that the same shape of the plug member 630 always extends into a flow path of the borescope vane cluster 620 and the seal 636 prevents gas path air ingestion through the borescope aperture 624.
Turning now to
Turning now to
In some embodiments, the shank 828 may be integrally formed with the boss 850, and in some embodiments, the boss 850 may provide for a connection (fixed or releasable) between the base 826 and the shank 828, as shown and described above. That is, in some embodiments, the boss 850 may define a base cavity therein for connection with the shank 828. For example, the shank 828 may include a base engagement element that fits within the base cavity defined by the boss 850 such that the shank 828 can be movably attached to the base 826.
As shown in
The base 826 further includes two mounting apertures 856, 858 that are configured to enable fixed mounting of the borescope plug 822 to a case of a gas turbine engine, as shown and described above. The mounting apertures 856, 858 are formed in the second side 829 of the base 826 and may pass completely through the base 826. The mounting apertures 856, 858 may be threaded to receive and engage with a fastener to enable mounting of the base to a case of a gas turbine engine. In other embodiments, the mounting apertures 856, 858 may be smooth and allow for a fastener to pass therethrough, with the fastener engaging with a nut or other locking element that is positioned on the first side 827 of the base 826.
The position of the mounting apertures 856, 858 is set such that the base 826 can only be installed into and attached to the case in a single orientation. That is, there is only one orientation of the base 826 that aligns the mounting apertures 856, 858 with installation apertures in the case and enables a bolt or other fastener to pass through the installation apertures in the case and to pass through or engage with the mounting apertures 856, 858. Stated another way, the configuration of the mounting apertures 856, 858 is not symmetric about the centroid 854.
In some embodiments, the non-symmetry of the mounting apertures 856, 858 may be achieved by placement of the mounting apertures 856, 858 at positions relative to the centroid 854. Specifically, an offset line 860 drawn through the center of a first mounting aperture 856 and through the center of a second mounting aperture 858 does not pass through the centroid 854 or does not include the point defined by the centroid 854. That is, the offset line 860 defined by the first and second mounting apertures 856, 858 is offset from the centroid 854. Accordingly, only one orientation of the base 826 relative to a case will allow for installation of the base 826 into the case and fasteners to attach or connect the base 826 to the case.
As shown in
It will be appreciated that the presently described offset of the mounting apertures on a base of a borescope plug may be applied to any given geometry of the base. For example, turning to
Turning now to
As shown, the borescope plug 1222 includes a base 1226, a shank 1228, and a plug member 1230. In this embodiments, the base 1226 and the shank 1228 are separate elements that are connected together at the base cavity 1244, as described above. Accordingly, the shank 1228, and thus the plug member 1230, can move relative to the base 1226. The base 1226 is fixedly attached or otherwise connected to the case 1212, e.g., through mounting apertures as described above, and the plug member 1230 and shank 1228 can move relative thereto.
The shank 1228 has a base engagement element 1238 at a first end of the shank 1228 and the plug member 1230 is at a second (opposite) end of the shank 1228. The shank 1228 further includes an optional flange 1232, similar to that described above, located at the second end of the shank 1228 between the shank 1228 and the plug member 1230.
In this embodiment, as described above, a retainer 1234 is arranged about a portion of the shank 1228 and maintains the shank 1228 within the base cavity 1244, while allowing the shank 1228 and plug member 1230 to rotate about a plug axis Ap. The retainer 434 has a retainer aperture 442 that is wide enough to enable the shank 428 to pass therethrough and also enable movement of the shank 428 within the retainer aperture 442. However, the retainer aperture 442 has a smaller diameter or shape than a diameter or shape of the base engagement element 438. The base engagement element 438 fits within a base cavity 444 of the base 426 that is configured to receive the base engagement element 438. The base engagement element 438 is sized to be smaller than the base cavity 444 such that the shank 428 can rotate about the shank axis A. It is noted that the plug axis Ap and the shank axis As are the same axis in these illustrations.
The base engagement element 1238 is sized such that some amount of movement of the base engagement element 1238 within the base cavity 1244 is possible. Accordingly, in addition to rotational movement about the shank axis As the base engagement element 1238 is enabled to move laterally or in a plane perpendicular to the shank axis As or at least have some amount of freedom of movement. In some configurations, the base engagement element 1238 can translate across a plane parallel to a surface of the base 1226. Similar to that described above, because the shank 1228 can rotate, the plug member 1230 has a round geometry such that the same shape of the plug member 1230 always extends into a flow path of the borescope vane cluster 1220.
In this embodiment, the anti-rotation of the shank 1228 and plug member 1230 is configured with a pin as a first anti-rotation element 1264. The anti-rotation elements are provided in the engagement between the base engagement element 1238 and the base 1226 (e.g., with the boss 1250 of the base 1226). The base 1226 includes a first anti-rotation element 1264 and the base engagement element 1238 includes a second anti-rotation element 1266 (e.g., a slot configuration such as shown in
Turning now to
Turning now to
The base 1426 includes two mounting apertures 1456, 1458 that are configured to enable fixed mounting of the base 1426 to a case of a gas turbine engine. The mounting apertures 1456, 1458 are formed in the second side 1429 of the base 1426 and may pass completely through the base 1426 or may extend only a portion of the way through the base 1426. The mounting apertures 1456, 1458 may be threaded to receive and engage with a fastener to enable mounting of the base to a case of a gas turbine engine. In other embodiments, the mounting apertures 1456, 1458 may be smooth and allow for a fastener to pass therethrough, with the fastener engaging with a nut or other locking element that is positioned on the first side of the base 1426.
The position of the mounting apertures 1456, 1458 is set such that the base 1426 can only be installed into and attached to the case in a single orientation. That is, there is only one orientation of the base 1426 that aligns the mounting apertures 1456, 1458 with installation apertures in the case and enables a bolt or other fastener to pass through the installation apertures in the case and to pass through or engage with the mounting apertures 1456, 1458. Stated another way, the configuration of the mounting apertures 1456, 1458 is not symmetric about at least one of the major axis 1470 or minor axis 1472.
In some embodiments, the non-symmetry of the mounting apertures 1456, 1458 may be achieved by placement of the mounting apertures 1456, 1458 at positions relative to the axes 1470, 1472. In this illustrative embodiment, a first mounting aperture 1456 is offset from the major axis 1470 by an offset distance 1474. Further, a second mounting aperture 1458 is positioned on the major axis 1470. Although the distance from the respective mounting apertures 1456, 1458 to the minor axis 1472 may be the same, the offset distance 1474 enables only a single configuration/orientation of the base 1426 to be installed into a case of a gas turbine engine. In some embodiments, the offset distance 1474 may be 1/10 of an inch or less (0.254 cm or less). Further, although shown with the second mounting aperture 1458 located on the major axis 1470, such configuration is not to be limiting, as the second mounting aperture may be offset from the major axis by a different offset distance, or with the same offset distance, but symmetric over the minor axis, such that only a single installation orientation is possible.
Turning now to
Although shown and described above with respect to certain configurations, orientations, geometries, etc., those of skill in the art will appreciate that variations can be implemented without departing from the scope of the present disclosure. For example, although shown as a circular or semi-spherical, the base engagement element can take any shape or geometry. For example, in some embodiments, the base engagement element can be squared or otherwise include a flat or engaging surface that prevents rotation of the shank while allowing for lateral movement. Further, in embodiments having a rounded or spherical shape, a pin-and-slot configuration may be employed (i.e., a combination of the anti-rotation features of
Further, although described with respect to a borescope plug, those of skill in the art will appreciate that various embodiments and concepts provided herein can be applied to any type of plugging configuration wherein high stresses are possible on a shank of a plug structure.
Advantageously, embodiments described herein provide an improved plug configuration that reduces or eliminate high stresses that are applied to one or more components of the plug. That is, in accordance with some embodiments, stresses applied to and within a plug can be greatly reduced by separating a plug section (e.g., shank and plug member) from a mounting plate (e.g., base). Further, the two-piece separated design of the plugs provides a fixed/pinned arrangement which allows small axial and tangential relative movement between a vane and a base of the plug.
Further, advantageously, embodiments of the present disclosure may improve installation efficiency by only allowing for a single installation orientation of the base of the borescope plug to a case of a gas turbine engine. The offset holes of embodiments of the present disclosure may prevent installing the borescope upside down (specifically the orientation of the plug extending into the gas path). If the plug is installed upside down, the plug would not seal the gas path air and embodiment described herein prevent such installation. Further, advantageously, the pin configuration for anti-rotation reduces the likelihood of binding of the shank to the base and such configuration may be less costly and easy to manufacture as compared to other configurations. Moreover, advantageously, embodiments described herein may prevent borescope plug breakage, ensure proper installation and sealing, prevent fractures and thermal and mechanical mismatch between the outer case hole and inner flow guide/flow path hole.
The use of the terms “a,” “an,” “the,” and similar references in the context of description (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or specifically contradicted by context. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.
While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions, combinations, sub-combinations, or equivalent arrangements not heretofore described, but which are commensurate with the scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments.
For example, although an aero or aircraft engine application is shown and described above, those of skill in the art will appreciate that borescope configurations as described herein may be applied to industrial applications and/or industrial gas turbine engines, land based or otherwise. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
This application is a continuation-in-part application of the legally related U.S. Ser. No. 15/231,023, filed Aug. 8, 2016, the contents of which are incorporated by reference herein in its entirety.
Number | Date | Country | |
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Parent | 15231023 | Aug 2016 | US |
Child | 16202817 | US |