The present invention relates to gas turbine engines and, more particularly, to structure supporting a radially inner ring structure relative to a radially outer casing of the engine.
In gas turbine engines, a radially inner structure, such as a bearing housing, may be supported relative to an outer casing of the engine by radially extending struts. The struts may be welded to the outer casing and extend radially through an outer duct structure defining an outer boundary for a hot working gas flow path, pass through the flow path, and extend through an inner duct structure defining a boundary for the flow path to a welded attachment location on the bearing housing. Since such a structure is formed as a welded structure, repairs typically necessitate cutting out parts of the structure and welding in new structure.
Alternatively, the bearing housing may be supported relative to the outer casing by tie rods extending radially from the outer casing to the bearing housing to radially locate the bearing housing. While such a radial rod support structure may provide good load transfer in the radial direction, such a structure typically must be maintained in radial tension and does not provide substantial support against axial loads applied to the bearing housing.
In accordance with an aspect of the invention, a turbine assembly is provided in a turbine engine, the turbine assembly having an outer casing, an inner structural ring, and an annular gas path defined between outer and inner flow path walls for conducting a gas flow through the turbine assembly in an axial direction, and further comprising: a plurality of structural struts spaced apart in a circumferential direction, each strut including a strut body extending in a radial direction between and supporting the inner structural ring to the outer casing; a fairing surrounding each of the struts in an area extending between the outer and inner flow path walls; a first strut end at a radially outer end of the strut body and detachably attached to the outer casing with a first fastener structure engaging the outer casing; and a second strut end at a radially inner end of the strut body and detachably attached to the inner structural ring with a second fastener structure engaging the inner structural ring.
The outer casing may include a strut aperture defined by an aperture surface and the first strut end may include a boss comprising an outer boss surface engaged against the aperture surface, and the first strut end can further include an outer flange extending perpendicular to the radial direction and extending over and positioned in contact with a portion of the outer casing.
The first fastener structure can include bolts that pass through the outer flange and that are engaged in holes in the outer casing.
The strut body can define a diametric dimension that is less than a diametric dimension of the outer boss surface parallel to the diametric dimension of the strut body, such that the strut body is spaced from the aperture surface at a location where the strut body is radially adjacent to the aperture surface.
The second strut end can include an inner flange extending outward from the strut body and perpendicular to the radial direction of the strut, the inner flange can include a planar surface facing radially inward and engaging a planar surface of the inner ring structure that faces radially outward.
The second fastener structure can include bolts passing through the inner flange and engaged in holes in the inner structural ring.
A spigot can be provided protruding from the inward facing planar surface and engaging within a recess in the outward facing planar surface to locate the second strut end at a predetermined location with reference to directions perpendicular to the radial direction.
The inner flange can be positioned in a T-shaped slot formed in the inner structural ring.
The inner structural ring can comprise first and second ring portions coupled together to sandwich the inner flange between the first and second ring portions.
The first and second ring portions can be coupled at a joint overlapping the inner flange.
The second fastener structure can comprise fasteners extending through and retaining the first and second ring portions in engagement with each other.
The T-shaped slot can include radially outward extending, inward angled sides and the inner flange can have a dove tail cross section to engage against the angled sides.
The inward facing surface can be defined on a protruding area of the inner flange having a dimension, in the circumferential direction, that is less than a width of the inner flange in the circumferential direction.
The strut body can have an airfoil shaped cross section including opposing sides parallel to a direction of gas flow through the annular gas path.
In accordance with another aspect of the invention, a turbine assembly is provided in a turbine engine, the turbine assembly having an outer casing, an inner structural ring, and an annular gas path defined between outer and inner flow path walls for conducting a gas flow through the turbine assembly in an axial direction, and further comprising: a plurality of structural struts spaced apart in a circumferential direction, each strut including a strut body extending in a radial direction between and supporting the inner structural ring to the outer casing; a fairing surrounding each of the struts in an area extending between the outer and inner flow path walls; a first strut end at a radially outer end of the strut body and detachably attached to the outer casing with a first fastener structure engaging the outer casing, the first fastener structure including a plurality of bolts for retaining the first strut end to the outer casing; and a second strut end at a radially inner end of the strut body and detachably attached to the inner structural ring with a second fastener structure, the second fastener structure including a plurality of bolts engaged in the inner structural ring.
The first strut end may include an outer flange extending perpendicular to the radial direction and the bolts of the first fastener structure can pass through the outer flange and engage in holes in the outer casing.
The second strut end can includes an inner flange extending outward from the strut body and perpendicular to the radial direction of the strut, the inner flange can include a surface facing radially inward and engaging a surface of the inner ring structure that faces radially outward.
The bolts of the second fastener structure can pass through the inner flange and are engaged in holes in the inner structural ring.
The inner structural ring can include first and second ring portions that cooperate with each other to clamp the inner flange to the inner ring structure.
The bolts of the second fastener structure can pass through the first and second ring portions to retain the second strut end in engagement with the inner ring structure.
While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying Drawing Figures, in which like reference numerals identify like elements, and wherein:
In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, and not by way of limitation, a specific preferred embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention.
The combustor 16 combines a portion of the compressed air from the compressor apparatus with a fuel and ignites the mixture creating combustion products defining hot working gases. The working gases travel from the combustor 16 to the turbine section 17. Within each turbine 18, 20 and 22 in the turbine section 17 are rows of stationary vanes (not shown) and rotating blades (not shown). For each row of blades, a separate disc (not shown) is provided. The discs forming part of the high pressure turbine 18 are coupled to a first rotatable shaft 26 (see
An annular exhaust gas path 42 is defined between an outer flow path wall 44 and an inner flow path wall 46. The gas path 42 conducts hot gases in an axial direction from the low pressure turbine 20 to the power turbine 22 and divides the exhaust casing cavity into an outer casing cavity or cavity portion 40a and an inner exhaust casing cavity or cavity portion 40b. The outer exhaust casing cavity 40a is generally defined between the outer ring 36 of the exhaust casing 25 and the outer flow path wall 44, and the inner casing cavity 40b is generally defined between the inner flow path wall 46 and a cone 49 extending between the inner ring 38 and a front or upstream end of the power turbine 22.
Referring to
It may be noted that although six struts 52 are illustrated herein (
As seen in
Referring to
In accordance with an aspect of the invention illustrated in
The first strut end 64 is formed with an outer flange 76 defining a portion of the first fastener structure 68 and extending perpendicular to the radial direction of the strut 52, as may be defined by a radial axis AR of the strut 52. The outer flange 76 extends over and is positioned in contact with a portion of the outer casing 36. For example, the outer casing 36 may be formed with a portal structure 78 that defines at least a portion of the strut aperture 72 and provides a planar outward facing surface 78a for cooperating with a planar inward facing surface 76a of the outer flange 76. The first fastener structure 68 can further include bolts 80 located around the periphery of the first strut end 64, passing through holes in the outer flange 76 and engaged in holes 82, e.g., threaded holes, in the outer casing 36. The positioning of the outer flange 76 on the cooperating surface 78a of the portal structure 78 can operate to locate the second end 66 of the strut 52 at a predetermined radially inner position. It may be understood that the bolts 80 could optionally comprise studs positioned in threaded holes 82 in the outer casing 36, and nuts engaged on the studs to retain the outer flange 46 in engagement on the portal structure 78 of the outer casing 36.
In accordance with a further aspect of the invention illustrated in
Referring to
In accordance with another aspect of the invention shown in
The inner flange 184 is positioned in a T-shaped slot 196 formed in the inner ring 138, as viewed circumferentially at an axial cross section. The “T” is defined by a vertical leg parallel to the radial axis AR and a horizontal leg parallel to the outward facing surface 138S and extending in axial direction. The inner ring 138 comprises first and second ring portions 138a, 138b coupled together to sandwich the inner flange between the first and second ring portions and to define a portion of the second fastener structure 170 formed in the inner ring 138. In particular, the ring portions 138a, 138b have respective forward and aft portions of the horizontal leg of the T-shaped slot 196 formed in them to receive corresponding forward and aft portions 184a, 184b of the inner flange 184. The forward and aft portions 184a, 184b of the inner flange 184 and the second end 166 of the strut 52 form a T-shaped inner end corresponding to the T-shaped slot 196. The reduced cross sectional portion of the strut body 52a extends through a channel 198 defined at a radial outer end of the T-shaped slot 196, and a clearance may be provided between the strut body 52a and the edges of the channel 198 to accommodate a limited amount of axial movement of the strut body 52a relative to the edges of the channel 198 while radially retaining the second end 166 in engagement with the inner ring 138.
The first and second ring portions 138a, 138b are joined together at a joint 200 overlapping, in the axial direction, the inner flange 184 to enclose the inner flange 184. Referring additionally to
The circumferentially extending flange segments 184c, 184d define a T-shaped cross section, as viewed in the axial direction at a circumferential cross section. The T-shaped cross section formed by the circumferentially extending flange segments 184c, 184 may be referenced as a circumferential T-shaped cross section of the inner flange 184, and the previously described T-shaped cross section of the inner flange 184 formed by the forward and aft flange portions 184a, 184b may be referenced as an axial T-shaped cross section of the inner flange 184. It may be understood that the second end 166 of the strut 52 can be assembled to the first ring portion 138a by relative axial movement causing the forward flange portion 184a to engage within the slot 196, and subsequently engaging the second ring portion 138b over the aft flange portion 184b and into engagement with the first ring portion 138a.
Referring to
The T-shaped slot 196 is formed with similarly radially outward angled sides, angling circumferentially in toward each other, for cooperating in engagement with the side portions 204, 206. The dove tail configuration of the inner flange 184′ provides a larger structural cross section for the flange and can provide a larger surface area for contact between the inner flange 184′ and the T-shaped slot 196.
It may also be understood that, although the configuration of the strut 52 depicted in
The described configuration provides removable or detachable struts 52 that can be easily assembled to and removed from the turbine exhaust casing 25. As noted above, the struts 52 are configured as rigid structural members that are resistant to movement under loads, such as high blow-off loads within the casing 25, without additional frame or support bracing in order to provide a stationary, rigid support for the rear bearing 51 of the turbine. Further, the outer and inner connections between the struts 52 and the outer case 36 and inner ring 38 (138) are configured to accurately align the inner ring 38 (138) to a predetermined axial and radial location, and thereby provide an accurate positioning of the bearing 51 during assembly. The end structure of the struts 52, including for example the radially outer boss 74 and the radially inner spigot 92, in addition to providing the described alignment, can take shear loading that would otherwise go into the bolts associated with the first and second fastener structures 68, 70.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US2014/047179 | 7/18/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2016/010554 | 1/21/2016 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
4979872 | Myers et al. | Dec 1990 | A |
4987736 | Ciokajlo et al. | Jan 1991 | A |
4989406 | Vdoviak et al. | Feb 1991 | A |
5292227 | Czachor et al. | Mar 1994 | A |
5312227 | Grateau et al. | May 1994 | A |
5609467 | Lenhart et al. | Mar 1997 | A |
7383686 | Aycock et al. | Jun 2008 | B2 |
20100303608 | Kataoka et al. | Dec 2010 | A1 |
20100307165 | Wong et al. | Dec 2010 | A1 |
20100322759 | Tanioka | Dec 2010 | A1 |
20110286851 | Benkler et al. | Nov 2011 | A1 |
20120027604 | McDonald et al. | Feb 2012 | A1 |
20130011242 | Beeck | Jan 2013 | A1 |
20130052006 | Petty | Feb 2013 | A1 |
20130115079 | Farah et al. | May 2013 | A1 |
Number | Date | Country |
---|---|---|
103557035 | Feb 2014 | CN |
104919140 | Sep 2015 | CN |
1076367 | Jul 1967 | GB |
2084261 | Apr 1982 | GB |
2014051686 | Apr 2014 | WO |
Entry |
---|
PCT International Search Report and Written Opinion dated Apr. 1, 2015 corresponding to PCT Application No. PCT/US2014/047179 filed Jul. 18, 2014. |
Number | Date | Country | |
---|---|---|---|
20170130608 A1 | May 2017 | US |