Gas turbine engine including a rotating blade assembly

A rotating blade assembly for a turbine engine having a drive shaft, the rotating blade assembly comprising a disc, at least one blade assembly, and a retainer. The disc being operably coupled to the drive shaft and including a seat having at least a portion of a first through hole. The at least one blade assembly having an upper platform, a lower platform, a dovetail extending from the lower platform, and a blade extending between the upper platform and the lower platform. The retainer assembly securing the disc to the at least one blade assembly and comprising a hollow tubular element, a pin, and a fastener.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to Italian Patent Application No. 102021000029963, filed Nov. 26, 2021, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This disclosure generally relates to a gas turbine engine, and more specifically to a rotating blade assembly of the gas turbine engine.

BACKGROUND

Turbine engines, and particularly gas turbine engines, are rotary engines that extract energy from a flow of working air passing serially through a compressor section, where the working air is compressed, a combustor section, where fuel is added to the working air and ignited, and a turbine section, where the combusted working air is expanded and work taken from the working air to drive the compressor section along with other systems, and provide thrust in an aircraft implementation. The compressor and turbine stages comprise axially arranged pairs of rotating blades and stationary vanes. The gas turbine engine can be arranged as an engine core comprising at least a compressor section, a combustor section, and a turbine section in axial flow arrangement and defining at least one rotating element or rotor and at least one stationary component or stator.

DETAILED DESCRIPTION

Aspects of this disclosure relate to a rotating blade assembly for a gas turbine engine including a drive shaft. The rotating blade assembly further including a disc operably coupled to the drive shaft and including a seat having at least a portion of first through hole, and at least one blade assembly having a dovetail. A retainer assembly can secure the at least one blade assembly to the disc. Aspects of this disclosure are described in terms of a gas turbine engine, specifically a gas turbine engine including a counter-rotating section. In other words, a counter-rotating gas turbine engine. As used herein, the term “counter-rotating section”, or iterations thereof can refer to a portion of the gas turbine engine including a set of axially adjacent, serially arranged, rotating components (e.g., blades) which rotate in opposing circumferential directions. It will be understood, however, that although described in terms of the counter-rotating gas turbine engine that aspects of the disclosure described herein are not so limited and can have general applicability within any suitable gas turbine engine, a turboprop, turboshaft or a turbofan engine having a power gearbox, in non-limiting examples. It will be further understood, however, that aspects of the disclosure described herein are not so limited and can have general applicability within other gas turbine engines. For example, the disclosure can have applicability for a rotating blade assembly in other engines or vehicles, and can be used to provide benefits in industrial, commercial, and residential applications.

As used herein, the term “forward” or “upstream” refers to moving in a direction toward the gas turbine engine inlet, or a component being relatively closer to the gas turbine engine inlet as compared to another component. The term “aft” or “downstream” used in conjunction with “forward” or “upstream” refers to a direction toward the rear or outlet of the gas turbine engine or being relatively closer to the gas turbine engine outlet as compared to another component.

As used herein, “a set” can include any number of the respectively described elements, including only one element. Additionally, the terms “radial” or “radially” as used herein refer to a dimension extending between a center longitudinal axis of the gas turbine engine and an outer engine circumference.

FIG.1is a schematic cross-sectional diagram of a gas turbine engine10for an aircraft. The gas turbine engine10has a generally longitudinally extending axis or centerline12extending from a forward direction14to an aft direction16. The gas turbine engine10can include at least one counter-rotating portion. As such, the gas turbine engine10can be defined as a counter-rotating gas turbine engine. The gas turbine engine10includes, in downstream serial flow relationship, a fan section18including a forward fan assembly20and an aft fan assembly21, a counter-rotating compressor section22including at least one counter-rotating section, a combustion section28including a combustor30, a counter-rotating turbine section32including at least one counter-rotating section, and an exhaust section38.

In the illustrated gas turbine engine10, the counter-rotating compressor section22can include a counter-rotating low-Pressure (LP) compressor24, and a counter-rotating high-Pressure (HP) compressor26, while the counter-rotating turbine section32can include a counter-rotating HP turbine34, and a counter-rotating LP turbine36. It will be understood that aspects of the disclosure can have applicability toward other turbines engines, including engines without any counter-rotating sections, or turbine engines including a portion that is non counter-rotating. As a non-limiting example, aspects of the disclosure can have applicability toward other gas turbine engines not including a counter-rotating LP turbine. For example, turbine engines having LP turbines in which static circumferentially-arranged vanes are axially spaced from rotating circumferentially-arranged blades are also contemplated.

The fan assemblies20and21are positioned at a forward end of the gas turbine engine10as illustrated. The terms “forward fan” and “aft fan” are used herein to indicate that one of the fan assemblies20is coupled axially upstream from the aft fan assembly21. It is also contemplated that the fan assemblies20,21can be positioned at an aft end of gas turbine engine10. Fan assemblies20and21each include a plurality of rows of fan blades40positioned within a fan casing42. Fan blades40are joined to respective rotor discs44that are rotatably coupled through a respective forward fan shaft46to the forward fan assembly20and through an aft fan shaft47to the aft fan assembly21.

The counter-rotating HP compressor26, the combustor30, and the counter-rotating HP turbine34form an engine core48of the gas turbine engine10. The gas turbine engine core48is surrounded by an outer casing50that can be coupled with the fan casing42. The counter-rotating HP turbine34is coupled to the counter-rotating HP compressor26via a core rotor or shaft52. In operation, the gas turbine engine core48generates combustion gases that are channeled downstream to the counter-rotating LP turbine36which extracts energy from the gases for powering fan assemblies20,21through their respective fan shafts46,47.

The counter-rotating LP turbine36includes an outer rotor54positioned radially inward from the outer casing50. The outer rotor54can have a generally frusto-conical shape and include a first set of airfoils56, circumferentially arranged, that extend radially inwardly towards the engine centerline12.

The counter-rotating LP turbine36further includes an inner rotor58arranged substantially coaxially with respect to, and radially inward of, the outer rotor54. The inner rotor58includes a second set of airfoils60circumferentially arranged and axially spaced from the first set of airfoils56. The inner rotor58can further be defined as a first rotor, while the outer rotor54can be defined as a second rotor. The second set of airfoils60extend radially outwardly away from the engine centerline12. The first and second sets of airfoils56,60together define a plurality of turbine stages62. In the example ofFIG.1, five turbine stages62are shown, and it will be understood that any number of stages can be utilized. Furthermore, while the first set of airfoils56are illustrated as being forward of the second set of airfoils60, the first and second sets of airfoils56,60can be arranged in any suitable manner, including the first set of airfoils56being positioned aft of the second set of airfoils60.

While the gas turbine engine10is described in the context of including a rotating outer rotor54and rotating inner rotor58, it is further contemplated that either of the first set of airfoils56or the second set of airfoils60can be included in, or form part of, a fixed stator within the gas turbine engine10. In one example, the first set of airfoils56can form a set of circumferentially-arranged static vanes forming part of an outer stator within the gas turbine engine10, while the second set of airfoils60is coupled to the rotatable inner rotor58. In another example, the second set of airfoils60can be in the form of static vanes coupled to an inner stator within the gas turbine engine10, with the first set of airfoils56being in the form of blades coupled to an outer rotor.

Complementary to the outer rotor54and inner rotor58, the stationary portions of the gas turbine engine10, such as the outer casing50, are also referred to individually or collectively as a stator63. As such, the stator63can refer to the combination of non-rotating elements throughout the gas turbine engine10.

In operation, the airflow exiting the fan section18is split such that a portion of the airflow is channeled along a main flow path15into the counter-rotating LP compressor24, which then supplies pressurized air65to the counter-rotating HP compressor26, which further pressurizes the air. The pressurized air65from the counter-rotating HP compressor26is mixed with fuel in the combustor30and ignited, thereby generating combustion gases66along the main flow path15. Some work is extracted from these combustion gases66by the counter-rotating HP turbine34, which drives the counter-rotating HP compressor26. The combustion gases66are discharged along the main flow path15into the counter-rotating LP turbine36, which extracts additional work to drive the counter-rotating LP compressor24, and the exhaust gas is ultimately discharged from the gas turbine engine10via the exhaust section38. The driving of the counter-rotating LP turbine36can drive rotation of the forward fan assembly20and the counter-rotating LP compressor24.

A portion of the pressurized air65can be drawn from the counter-rotating compressor section22as bleed air67. The bleed air67can be drawn from the pressurized air65and provided to engine components requiring cooling. The temperature of pressurized air65entering the combustor30is significantly increased above the bleed air67temperature. The bleed air67may be used to reduce the temperature of the core components downstream of the combustor.

Some of the air supplied by the fan20, such as the bleed air67, can bypass the gas turbine engine core48and be used for cooling of portions, especially hot portions, of the gas turbine engine10, or for cooling or powering other portions of the gas turbine engine10. In the context of a turbine engine, the hot portions of the gas turbine engine are normally downstream of the combustor30, especially the counter-rotating turbine section32, with the counter-rotating HP turbine34being the hottest portion as it is directly downstream of the combustion section28. Other sources of cooling fluid can be, but are not limited to, fluid discharged from the counter-rotating LP compressor24or the counter-rotating HP compressor26.

FIG.2is a cross-sectional axial view of the gas turbine engine10ofFIG.1as seen from cut II ofFIG.1. The gas turbine engine10can include a rotating blade assembly100within a portion of the gas turbine engine10. The rotating blade assembly100is configured to rotate about a rotational axis, illustrated as the axis12. The rotating blade assembly100can be provided within a portion of the counter-rotating LP turbine36. It will be appreciated, however, that the rotating blade assembly100can be provided within any suitable portion of the gas turbine engine10such as within any suitable portion of the counter-rotating compressor section22or the counter-rotating turbine section32. Further, although a single rotating blade assembly100is illustrated, it will be appreciated that there can be any number of one or more rotating blade assemblies100provided within the gas turbine engine10.

The rotating blade assembly100can include a blade assembly102, a disc104, and a set of retainer assemblies106. At least a portion of the disc104can be operably coupled to a rotating component of the gas turbine engine10. As a non-limiting example, the disc104can be operably coupled to a drive shaft98of the gas turbine engine10. At least a portion of the blade assembly102can be operably coupled to another rotating component. As a non-limiting example, the blade assembly can be coupled to the inner rotor58or the outer rotor54.

The blade assembly102can include an inner platform108, an outer platform110, located radially outward form the inner platform108with respect to the engine centerline12, and a set of circumferentially spaced blades112extending therebetween. As illustrated, the set of circumferentially spaced blades112can include the first set of airfoils56. It will be appreciated, however, that the set of circumferentially spaced blades112can include any suitable set of airfoils such as, but not limited to, the second set of airfoils60. The set of circumferentially spaced blades112can be any suitable blade or vane within the gas turbine engine10that is operably coupled to the outer rotor54, the inner rotor58, or a static portion of the gas turbine engine10(e.g., the stator63). The outer platform110can be operably coupled to a rotating element of the gas turbine engine10. As a non-limiting example, the outer platform110can be operably coupled to the inner rotor58or the outer rotor54of the gas turbine engine10. A dovetail114can extend from a radially inner portion of the inner platform108.

The disc104can extend between outer peripheries in the axial and radial directions. The disc104can further encase or confront at least a portion of the blade assembly102. As a non-limiting example, the disc104can encase a radially inner portion of the blade assembly102. As a non-limiting example, the disc104can encase a portion of the dovetail114. The disc104can further include inner peripheries. At least a portion of the inner peripheries can confront or contact the blade assembly102or the retainer assembly106. At least a portion of the inner peripheries can define a seat126at least partially encasing or confronting the dovetail114. The seat126can further be defined by a first band122and a second band124. As illustrated, the second band124can be provided axially forward or otherwise upstream, with respect to the combustion gasses66, of the first band122. The disc104can be sized and/or shaped such that the disc104can fit over, or otherwise encase, at least a corresponding portion of the dovetail114.

The disc104can further include a projection142extending from a portion of the remainder of the disc104. As illustrated, the projection142can extend from a portion of the first band122. The projection142can be operatively coupled to the drive shaft98of the gas turbine engine10. The drive shaft98can be any suitable drive shaft98as described herein such as, but not limited to, the forward fan shaft46, the aft fan shaft47, or the core shaft52. As such, in the case where the rotating blade assembly100is provided within the counter-rotating turbine section32, the rotation of the rotating blade assembly100can be used to rotationally drive the drive shaft98, which in turn can drive an upstream portion of the gas turbine engine10(e.g., a rotating component of the counter-rotating compressor section22, a portion of the fan section18, etc.). Although the projection142is illustrated, it will be appreciated that the disc104can be formed without the projection142. As such, in some implementations the disc104is only coupled to the rotating blade assembly100and not the drive shaft.

The retainer assembly106can extend through a portion of the disc104and operably couple the disc104to the blade assembly102. As illustrated, the retainer assembly106can extend axially through the disc104and confront axially opposing ends of the disc104. As such, the retainer assembly106can axially retain the disc104around a portion of the blade assembly102. As a non-limiting example, the retainer assembly106can axially retain the disc104about the dovetail114of the blade assembly102.

The blade assembly102can be included within a set of circumferentially spaced blade assemblies102. The set of blade assemblies102can extend about the entirety of the engine centerline12to form a ring of blade assemblies102. At least a portion of the disc104, however, can continuously extend across an entirety of the engine centerline12. In other words, the disc104can form a 360 degree ring about the engine centerline12. As such, the disc104can extend across one or more blade assemblies102in the set of blade assemblies102. Similarly, the projection142can be formed as a continuous ring or band that extends about the entirety of the engine centerline12. Alternatively, the projection142can be formed in discrete sections such that the projection142is included within a set of segmented projections142that extend from respective portions of the disc104. As such, the disc104can be formed as a hub and spoke assembly when viewed in a plane normal to the engine centerline12and intersecting the disc104. The set of retainer assemblies106can include any suitable number of retainer assemblies106circumferentially spaced along the disc104. As a non-limiting example, the set of retainer assemblies106can be regularly or otherwise equally circumferentially spaced about the disc104. Alternatively, the two or more retainer assemblies106may be formed in groups in which the retainer assemblies106are closer to one another than they are to an adjacent group of retainer assemblies106. In any case, the disc104can be axially retained to each dovetail114of each blade assembly102of the set of blade assemblies102via the set of retainer assemblies106.

As illustrated, the blade assembly102, the disc104and the retainer assembly106are discrete components that are operably coupled to, or otherwise confront one another. It will be appreciated, however, that at least a portion of the blade assembly102, the disc104, or the retainer assembly106can be integrally formed with another portion of the rotating blade assembly100. As a non-limiting example, the retainer assembly106can be integrally formed with the second band124or the first band122of the disc104. As another non-limiting example, at least one of the first band122or the second band124can be integrally formed with the blade assembly102such that the blade assembly102and the disc104form a monolithic structure.

FIG.3is an exploded perspective view of the rotating blade assembly100ofFIG.2. The rotating blade assembly100can include the blade assembly102, the disc104, and the retainer assembly106.

Each blade112of the set of circumferentially spaced blades112can include an outer wall demarcated by a leading edge116and a trailing edge118, downstream or otherwise axially aft the leading edge116, a root119, and a tip120. The extension of the outer wall between the leading edge116and the trailing edge118can define a chord-wise direction. The extension of the outer wall between the root119and the tip120can define a span-wise direction. The root119can be coupled to, or otherwise integral with, the inner platform108. The tip120can be coupled to, or otherwise integral with the outer platform110.

A first through hole128can be defined by a portion of the disc104. As a non-limiting example, the first band122and the second band124can each include a portion of the first through hole128. A radially inner portion, or a distal end of the dovetail114can further include a portion of the first through hole128. When assembled, the first through hole128can extend continuously through the first band122, the dovetail114, and the second band124. The first through hole128can extend from an upstream to a downstream portion of the rotating blade assembly100in the axial direction.

Each retainer assembly106of the set of retainer assemblies106can include a tubular element, a pin132, and a fastener134. The tubular element can include any suitable tubular shape when viewed in a plane normal to the engine centerline12and intersecting the tubular element such as, but not limited to, a square tube, a cylindrical tube, or any other suitable tube. At least a portion of the retainer assembly106can confront, contact, or be coupled to the seat126of the disc104.

As a non-limiting example, the tubular element can be any suitable tubular element such as a bushing130. The bushing130can include a set of fingers131extending along a portion of the bushing130. Each finger131of the set of fingers131can be separated from an adjacent finger131by a void or absence of material. The bushing130can include a hollow interior defining a second through hole136. As such, the tubular element can further be defined as a hollow tubular element. The pin132can be aligned with and at least partially received within the first through hole128and the second through hole136. The pin132can terminate at a distal end138. When assembled, the distal end138can extend past the first through hole128. The bushing130can be aligned with the first through hole128. The bushing130can further include a first end defining a shoulder140, which, when assembled, can abut at least a portion of the disc104. As a non-limiting example, the shoulder140can abut the second band124. The fastener134can be secured to the distal end138of the pin132and abut a portion of the disc104. The tubular element can be generally defined as any suitable element that is expandable through mechanical features (e.g., the fingers131) when an external force is applied to an interior of the tubular element. It is further contemplated that the tubular element can be expandable through material properties (e.g., heat properties, elasticity, etc.). As a non-limiting example, the tubular element can be a rubber tube that expands when the external force is applied by the pin132.

FIG.4is a cross-sectional view of the rotating blade assembly100as seen from cut IV-IV ofFIG.3.

The first band122can include a first rib144. The second band124can include a second rib146, opposing the first rib144. As illustrated, the first rib144and the second rib146can be provided on axially opposite sides of the dovetail114. The first rib144and the second rib146can both interface, or otherwise contact a corresponding portion of the dovetail114. The first rib144and the second rib146can be used to radially retain the disc104on the blade assembly102.

The second band124can include a portion which overlaps a corresponding portion of the first band122. This overlapping portion can define a lap joint145formed between the first band122and the second band124. The lap joint145can define a coupling or an interface between the first band122and the second band124. It is contemplated that the lap joint145can further be used to align the first band122with respect to the second band124.

The second band124can include a portion which overlaps a corresponding portion of the first band122. This overlapping portion can define the lap joint145formed between the first band122and the second band124. The lap joint145can define a coupling or an interface between the first band122and the second band124. It is contemplated that the lap joint145can further be used to align the first band122with respect to the second band124.

As illustrated, the bushing130of the retainer assembly can extend through a portion of the first through hole128such that the second through hole136is aligned with the first through hole128. It is contemplated that the bushing130can end along a distal end148of the bushing130. The distal end148of the bushing130can be provided within a portion of the first through hole128. As a non-limiting example, the distal end148can be spaced from the first band122such that the bushing130does not physically contact the first band122.

It is further contemplated that the first through hole128and the second through hole136can each include a non-constant cross-sectional area when viewed in a plane normal to the engine centerline12and intersecting the disc104. As a non-limiting example, the first through hole128can include an area with a reduced cross-sectional area within a portion of the first band122when compared to the remainder of the first through hole128. The portion of the first through hole128with the reduced cross-sectional area can directly contact at least a portion of the pin132. As a non-limiting example, the bushing130can include a portion with a decreasing cross-sectional area. In other words, the bushing130can include a portion in which the cross-sectional area decreases linearly or non-linearly. As a non-limiting example, at least a portion the cross-sectional area of the bushing130can decrease from an upstream or axially forward portion to a downstream or axially aft portion. Similarly, the pin132can include a decreasing cross-sectional area when viewed in a plane normal to the engine centerline12and intersecting the pin132. As such, the pin132can be defined as a conical pin and the bushing can be defined as a conical bushing. The decreasing cross-sectional area of the pin132can correspond to the decreasing cross-sectional area of the bushing130such that the pin132can interface with the bushing130along the sections of the bushing130and the pin132defined by the decreasing cross-sectional areas. The interface between the bushing130and the pin132can be used to retain the pin132within the bushing130.

The shoulder140of the bushing130can interface with the disc104. As a non-limiting example, the shoulder140of the bushing130can interface with the second band124. The second band124can include a cutout150sized to receive the shoulder140of the bushing130. As such, a forward portion of bushing130can be flush with a forward portion of the second band124.

It is contemplated that at least a portion of the fastener134can abut a portion of the first band122. The fastener134can be any suitable fastener134such as, but not limited to, a nut, a hydraulic fastener, a magnetic fastener, a weld, an adhesive, or an electrical connection (e.g., an electro-actuated connection). As a non-limiting example, the fastener134can be defined by a nut. As such, the distal end138can further include a threaded portion corresponding to a threaded portion of the nut. As such, the nut can be fastened, or otherwise threaded onto the threaded portion of the pin132.

During assembly, the disc104can be fit over a corresponding portion of the dovetail114such that the first through hole128is continuously formed through the first band122, the second band124and the dovetail114. The first rib144and the second rib146can each interface with a corresponding portion of the dovetail114. The lap joint145can be sized and positioned to ensure that the first rib144and the second rib146are positioned within the correct position when assembled. Further, the lap joint145can be sized to ensure that the first through hole128is continuously formed through the disc104and the dovetail114once the disc104is positioned over the dovetail114. The bushing130can subsequently be aligned with the first through hole128and inserted therein. The bushing130can be inserted such that the shoulder140contacts or is received within the cutout150. The pin132can then be inserted into the second through hole136defined by the bushing130. As discussed herein, the distal end138of the pin132can extend past a termination of the first through hole128. The fastener134can then be placed, applied, fastened, or otherwise coupled to the distal end138of the pin132and abut a portion of the disc104(e.g., the first band122). The fastener134can apply an axial tightening or a closing force on the pin132to draw the pin132toward the fastener134, which is axially constrained by the disc104. As the pin132is drawn toward the fastener134, the pin132is first axially moved until it is in contact with the bushing130, where continued axial movement of the pin132next causes the shoulder140to abut the cutout150formed within the disc104. Through the shoulder140abutting the cutout150, and the fastener134abutting the disc104, opposing closing forces are exerted on opposing axial ends of the disc104, which, in turn, axially retains the disc104over the dovetail114. Any additional axial movement of the pin132causes the fingers131of the bushing130to radially expand and apply an expansive hoop force between the disc104and the dovetail114. As such, the bushing130can further be defined as an expandable bushing or an expandable tubular element, respectively, with it being understood that the expansion of the bushing130can be generated via any suitable method such as a mechanical component, or a material property of the bushing130. Similarly, the pin132can be generally defined as a component configured to actuate and expand the bushing130as described herein. The expansive hoop force, in turn, urges the dovetail114against the first rib144and the second rib146. Thus, with this type of connection, the retainer assembly106both axially constrains the disc104to the dovetail114as well as radially constrains the disc104to the dovetail114.

During operation of the gas turbine engine10, a working airflow can flow over a portion of the rotating blade assembly100. As a non-limiting example, the working airflow can flow over the set of circumferentially spaced blades112of the rotating blade assembly100. As a non-limiting example, the working airflow can be any suitable airflow within the gas turbine engine such as, but not limited to, the pressurized air65or the combustion gases66. In the case where the rotating blade assembly100is provided within the counter-rotating turbine section32, the rotating blade assembly100can extract work from the working airflow as it flows over the rotating blade assembly100. In the case where the rotating blade assembly100is provided within the counter-rotating compressor section22, the rotating blade assembly100can pressurize or otherwise compress the working airflow.

As discussed herein, the rotating blade assembly100can include a set of circumferentially spaced blade assemblies102that are discrete from another. It is contemplated that the disc104can be used to couple each blade assembly102of the set of blade assemblies102such that a continuous ring of blade assemblies102is formed. As such, the rotating blade assembly100can be formed as a rigid rotating blade assembly100by interconnecting the blade assemblies102through use of the disc104. This, in turn, can ensure that there are no or otherwise minimal radial clearance between the outer rotor54and the outer band110, and a portion of the disc104(e.g., the projection142) and the drive shaft98. The reduction or elimination of the clearances can ensure that the rotation of the set of blades102within the rotating blade assembly100is concentric with the rotation of the outer platform110or the outer rotor54. Similarly, the reduction or the elimination of the clearances can ensure that the disc104is concentric with the outer band110. With the concentric rotation and assembly of the rotating blade assembly100, the total amount of losses are reduced (e.g., frictional losses through adjacent pieces abutting one another. This ultimately ensures that the overall efficiency of the gas turbine engine10is increased when compared to the gas turbine engine10if it did not include the rotating blade assembly100with the disc104.

During normal operation of the gas turbine engine10, an operational force can be exerted on the rotating blade assembly100. The operational force can be defined as any suitable force exerted on the rotating blade assembly100during normal operation of the gas turbine engine10(e.g., a rotational force or a thermal load). As a non-limiting example, an operational force of 30k lb can be exerted on the rotating blade assembly100. The operational force can be exerted onto the disc104and define a radially inward force with respect to the engine centerline12. It is contemplated that the disc104can be formed to withstand these operational forces of the gas turbine engine10. As a non-limiting example, the interface of the disc104with the dovetail114(e.g., the first rib144and the second rib146) can be sized or formed to withstand these operational forces. During shutdown of the gas turbine engine10, however, a shutdown force, opposite the operational force, is exerted on the rotating blade assembly100. In other words, during shut down of the gas turbine engine10, a radially outward force can be exerted on the rotating blade assembly100. The shutdown force can be smaller than the operational forces. As a non-limiting example, the shutdown force can be 1/20thof the operational force. As a non-limiting example, if the operational force is 30k lb, the shutdown force can be 1.5k lb. Unlike the operational force, however, the shutdown force is transferred through a portion of the retainer assembly106as opposed to only the disc104. As such, the retainer assembly106is sized and formed to withstand the shutdown force. As the shutdown force is much smaller than the operational force, the retainer assembly106can be formed with a weaker material than the disc104, which ultimately reduces the material costs associated with the rotating blade assembly100.

FIG.5is a cross-sectional view of an exemplary rotating blade assembly200for use within the gas turbine engine ofFIG.1. The exemplary rotating blade assembly200is similar to the rotating blade assembly100; therefore, like parts will be identified with like numerals in the200series, with it being understood that the description of the like parts of the rotating blade assembly100applies to the exemplary rotating blade assembly200unless otherwise noted.

The rotating blade assembly200can include a blade assembly202, a disc204, and a retainer assembly206similar to the rotating blade assembly100. The blade assembly202, similar to the blade assembly102, can include a blade212extending from a root219to a tip (not illustrated), and a leading edge216to a trailing edge218. The root219can be coupled to an inner platform208of the blade assembly202, while the tip can be coupled to an outer platform (not illustrated) of the blade assembly202. A dovetail214can depend from the inner platform208. The disc204, similar to the disc104, can include a first band222and a second band224that together form a seat226. The first band222can optionally be operably coupled to a drive shaft through a projection242. The retainer assembly206, similar to the retainer assembly106, can include a bushing230, a pin232and a fastener234. The bushing230can include a shoulder240and a set of fingers231, which interfaces with a cutout250formed within a portion of the second band224. The pin232can be defined by a distal end238, and the fastener234can be secured to the distal end238. At least a portion of the disc204and the dovetail214can form a continuous first through hole228. An interior of the bushing230can define a second through hole236aligned with the first through hole228. The pin232can be provided at least partially within the second through hole236and the first through hole228. A lap joint245can be formed between the first band222and the second band224and define an interface or coupling between the first band222and the second band224.

The disc204is similar to the disc104as it includes the first band222and the second band224. The first band222, however, forms a plate abutting a portion of the dovetail214and the second band224. The second band224, however, can be formed to only extend across a radially inner portion of the rotating blade assembly200. In other words, the second band224does not extend forward of, or otherwise confront a portion of the dovetail214along a portion of the rotating blade assembly200including the retainer assembly206. Further, the only portion of the first through hole228defined by the second band224is the portion of the second band224opposing the dovetail214. In other words, the second band224does not define a full portion of the first through hole228on its own as the second band124does (e.g., the hole formed within an axially forward portion of the second band124). The bushing230can extend through a portion of the first through hole228and terminate within the first through hole228at a termination248.

The cutout250is similar to the cutout150, however, the cutout250is also at least partially formed within the dovetail214. As such, the shoulder240of the bushing230can abut at least a portion of the disc204and the dovetail214or blade assembly202. As illustrated, the first through hole228has a smaller axial length than the first through hole128. This is due to configuration of the disc204.

The bushing230is similar to the bushing130, except the bushing230can have a smaller axial length when compared to the bushing130. This is due to the smaller axial length of the first through hole228. This, in turn, reduces the material required for the manufacturing of the retainer assembly206. Further, the bushing230can include a wall251, which terminates at radially distal ends to define the shoulder240.

During operation of the gas turbine engine10, at least a portion of the working airflow can flow toward the disc204, thus defining a leakage fluid. It is contemplated that minimizing the leakage fluid within the gas turbine engine10can maximize the amount of working airflow that flows over the blades212, which in turn maximizes the amount of work extracted from the working airflow. With the wall251and the shoulder240, the bushing230can form a fluid tight seal between the disc204and the blade assembly202. This, in turn, ensures that a leakage fluid does not enter either of the first through hole228or the second through hole236. This reduces the total amount of leakage fluid, which in turn maximizes the overall efficiency of the rotating blade assembly200. It is contemplated that the remainder of the disc204can be used to limit the leakage fluid. As a non-limiting example, the first band222can be used to reduce or otherwise eliminate the leakage fluid, which can flow from an upstream portion of the rotating blade assembly200to a downstream portion of the rotating blade assembly200.

FIG.6is a radial view of the rotating blade assembly200ofFIG.5as seen from a plane normal to the engine centerline12and intersecting the rotating blade assembly200. The rotating blade assembly200can include the blade assembly202, which is included within a set of blade assemblies202circumferentially spaced with respect to one another.

The disc204can be coupled to the dovetail214through a dovetail connection defined by a tail254and a socket256. The disc204can include the tail254, which extends radially, with respect to the engine centerline12, from a remainder of the disc204. As a non-limiting example, the second band224can include the tail254, which extends radially from the reminder of the second band224.

The socket256can be formed between circumferentially adjacent portions of adjacent blade assemblies202. As illustrated, the socket256can be formed by circumferentially adjacent cutouts formed within a portion of adjacent dovetails214. The socket256can be sized and shaped to receive the tail254of the disc204.

During assembly of the rotatable blade assembly200, the tail254of the disc204can be inserted through or into the socket256. This can be done by sliding the tail254, and hence the disc204, into the socket256. At least a portion of the tail254can interface with the socket256. The interface between the tail254and the socket256can radially retain the disc204to the blade assembly202. This radial retention through the tail254and the socket256is similar to the radial retention between the first rib144and the second rib146, and the dovetail114of the rotatable blade assembly100. Further, as the bushing230directly contacts the dovetail214, at least a portion of the closing force that axially retains the disc204on the blade assembly202can be applied directly to the blade assembly202.

FIG.7is a cross-sectional view of an exemplary rotating blade assembly300of the gas turbine engine10ofFIG.1. The exemplary rotating blade assembly300is similar to the rotating blade assembly100,200; therefore, like parts will be identified with like numerals in the300series, with it being understood that the description of the like parts of the rotating blade assembly100,200applies to the exemplary rotating blade assembly300unless otherwise noted.

The rotating blade assembly300can include a blade assembly302, a disc304, and a retainer assembly306similar to the rotating blade assembly100,200. The blade assembly302, similar to the blade assembly102,202, can include a blade312extending from a root319to a tip (not illustrated), and a leading edge316to a trailing edge318. The root319can be coupled to an inner platform308of the blade assembly302, while the tip can be coupled to an outer platform (not illustrated) of the blade assembly302. A dovetail314can depend from the inner platform308. The disc304, similar to the disc104,204, can define a seat326. The disc304can optionally be operably coupled to a drive shaft through a projection342. The retainer assembly306, similar to the retainer assembly106,206, can include a bushing330with a set of fingers331, a pin332and a fastener334. The bushing330can be formed similar to the bushing230as it includes a wall351which terminates at radially distal ends to define a shoulder340. The shoulder340can interface with a cutout350at least partially formed within a portion of the dovetail314and a portion of the disc304. The bushing330can further be defined by a smaller axial length, similar to the bushing230, when compared to the bushing130. The pin332can be defined by a distal end338, and the fastener334can be secured to the distal end338. At least a portion of the disc304and the dovetail314can form a continuous first through hole328. An interior of the bushing330can define a second through hole336aligned with the first through hole328. The pin332can be provided at least partially within the second through hole336and the first through hole328. The bushing330can extend through a portion of the first through hole328and terminate within the first through hole328at a termination348.

The disc304is similar to the disc204in that is formed to only extend across a radially inner portion of the rotating blade assembly200. In other words, the disc204does not contact or interface with an axially forward portion of the dovetail314. The difference between the disc304, and the disc204, is that the disc204includes the first band222and the second band224. The disc204, however, can be defined as an integral disc304in which the first band122,222is integrally formed with the second band124,224. In other words, the disc304is formed as a monolithic structure that is axially retained to the blade assembly302via the retainer assembly306. The disc304can further be radially retained through use of any suitable radial retention assembly as described herein (e.g., the tail254and the socket256, or the first rib144and the second rib146).

FIG.8is a cross-sectional view of an exemplary rotating blade assembly400of the gas turbine engine10ofFIG.1. The exemplary rotating blade assembly400is similar to the rotating blade assembly100,200,300; therefore, like parts will be identified with like numerals in the400series, with it being understood that the description of the like parts of the rotating blade assembly100,200,300applies to the exemplary rotating blade assembly400unless otherwise noted.

The rotating blade assembly400can include a blade assembly402, a disc404, and a retainer assembly406similar to the rotating blade assembly100,200,300. The blade assembly402, similar to the blade assembly102,202,302, can include a blade412extending from a root419to a tip (not illustrated), and a leading edge416to a trailing edge418. The root419can be coupled to an inner platform408of the blade assembly402, while the tip can be coupled to an outer platform (not illustrated) of the blade assembly402. A dovetail414can depend from the inner platform408. The disc404, similar to the disc104,204,304, can define a seat426. The disc404can optionally be operably coupled to a drive shaft through a projection442. The disc404can be formed similar to the disc304in that it is an integral disc404. The retainer assembly406, similar to the retainer assembly106,206,306, can include a bushing430, a pin432and a fastener434. The bushing430can be formed similar to the bushing130,230,330in that it includes a shoulder440and a set of fingers431. The pin432can be defined by a distal end438, and the fastener434can be secured to the distal end438. At least a portion of the disc404and the dovetail414can form a continuous first through hole428. An interior of the bushing430can define a second through hole436aligned with the first through hole428. The pin432can be provided at least partially within the second through hole436and the first through hole428. The bushing430can extend through a portion of the first through hole428and terminate within the first through hole428at a termination448.

The retainer assembly406can further include a retainer plate458. The retainer plate458can abut a portion of the dovetail414and the disc404. The retainer plate458, similar to the disc104,204,304and the dovetail214,314can include a cutout450configured to receive the shoulder440of the bushing430. The retainer plate458can further include a through hole460that extends axially through a portion of the retainer plate458. The retainer plate458can be aligned with first through hole428such that the through hole460defines a portion of the first through hole428.

During assembly of the rotating blade assembly400, at least closing force, or the axial retention force generated by the retainer assembly406can be applied to the retainer plate458. As such, the retainer plate458can be used to axially retain the disc404to the blade assembly402.

FIG.9is a schematic axial view of an exemplary rotating blade assembly500of the gas turbine engine10ofFIG.1. The exemplary rotating blade assembly500is similar to the rotating blade assembly100,200,300,400; therefore, like parts will be identified with like numerals in the500series, with it being understood that the description of the like parts of the rotating blade assembly100,200,300,400applies to the exemplary rotating blade assembly500unless otherwise noted.

The rotating blade assembly500can include a set of blade assemblies502, a disc504, and a set of retainer assemblies506similar to the rotating blade assembly100,200,300,400. Each blade assembly502of the set of blade assemblies502can be similar to the blade assembly102,202,302,402. Each blade assembly502can include a blade512or a set of blades512, with each blade512extending from a root519to a tip (not illustrated), and a leading edge516to a trailing edge (not illustrated). The root519can be coupled to an inner platform508of the blade assembly502, while the tip can be coupled to an outer platform (not illustrated) of the blade assembly502. Each blade assembly502can include a dovetail514that can depend from the corresponding inner platform508of the blade assembly502. The disc504, as illustrated, is a schematic illustration of the disc504. It will be appreciated, however, that the disc504can be any suitable disc104,204,304,404as disclosed herein. The set of retainer assemblies506, as illustrated, is a schematic illustration of the retainer assembly506. It will be appreciated, however, that each retainer assembly506of the set of retainer assemblies506can include any suitable retainer assembly106,206,306,406as described herein.

As illustrated, the set of blade assemblies502can each include a corresponding dovetail514. Each dovetail514can be formed such that it is complementary to an adjacent dovetail514. A first contact region562can be formed between corresponding portions of adjacent dovetails514. The first contact region562can denote a region where adjacent dovetails514physically contact one another or are otherwise coupled to each other. Further, each dovetail514can be contacted by a portion of the disc504. As a non-limiting example, each dovetail514can be contacted by the disc504along a second contact region564. As a non-limiting example, the second contact region564can be the contact or interface between the first rib144or the second rib146of the rotating blade assembly100. As a non-liming example, the second contact region564can be the contact or interface between the tail254and the socket256of the rotating blade assembly200.

It is contemplated that the set of retainer assemblies506can be arranged in groups. As a non-limiting example, the set of retainer assemblies506can include a group of two retainer assemblies506. It will be appreciated, however, that each group of retainer assemblies506can include any number of one or more retainer assemblies506. As illustrated, each group of retainer assemblies506of the set of retainer assemblies506can extend through a portion of the disc504corresponding to every other blade assembly502. In other words, every other blade assembly502can be physically coupled to a retainer assembly506of the set of retainer assemblies506. This configuration can reduce the total number of retainer assemblies506needed in order to effectively couple the disc504to the set of blade assemblies502. Alternatively, the retainer assemblies506can be spread out over any number of blade assemblies502. As a non-limiting example, the set of retainer assemblies506can be provided along a portion of the disc504corresponding to every third, fourth, fifth, or nthblade assembly502. Alternatively, the set of retainer assemblies506can be provided along the disc504corresponding to every blade assembly502in the set of blade assemblies502.

Benefits of the present disclosure include a rotating blade assembly that can be used with a turbine engine (e.g., a counter-rotating turbine engine), which has an overall improved efficiency when compared to a conventional turbine engine (e.g., a non-counter-rotating turbine engine). For example, conventional turbine engines can include a set of rotating blades provided downstream of set of stationary vanes, which together form a stage of the non-counter-rotating turbine engine. During operation of the non-counter-rotating turbine engine, a working airflow, similar to the working airflow as described herein, can flow over the set of stationary vanes and subsequently to the set of adjacent rotating blades. The set of stationary vanes can be used to direct the working airflow such that it is incident with that leading edge of the set of rotating blades, thus limiting the windage losses associated with a non-incident working airflow. In a non-counter-rotating turbine engine, however, work is only extracted through the rotation of the set of rotating blades (e.g., the set of stationary vanes do not extract work from the working airflow). The present disclosure, however, is concerned with a rotating blade assembly for a counter-rotating turbine engine in which a stage is made up of two adjacent rotating blade assemblies. It is contemplated that the adjacent rotating blade assemblies can rotate in counter (e.g., opposite) circumferential directions with respect to one another, however, the rotating blade assemblies can be positioned such that the working airflow leaving the upstream rotating blade assembly can be incident with respect to their own leading edges. As such, windage losses are still avoided or otherwise limited, however, work can be extracted from both sets of rotating blade assemblies. This ultimately means that the total work output from the counter-rotating turbine engine can be larger when compared to a non-counter-rotating turbine engine of similar size (e.g., similar or same amount of total stages).

Further benefits of the present disclosure include a rotating blade assembly with reduced losses when compared to a rotating blade assembly used within a counter-rotating turbine engine without the disc as described herein. For example, a rotating blade assembly without the disc as described herein will form a non-rigid circumferential ring of blade assemblies within the working airflow. This, in turn, means that the blade assemblies have larger tolerances for how much they can move during the intended circumrenal movement (e.g., rotation) of the rotating blade assembly. The larger tolerances, in turn, cause the inner portions of the rotating blade assembly and the outer band will be non-concentric, which ultimately generates losses. The rotating blade assembly, as described herein, however, includes a circumferential disc that interconnects each of the blade assemblies within the rotating blade assembly. In other words, the disc can be used to form a rigid structure between adjacent blade assemblies. This, in turn, reduces or eliminates the clearances between adjacent components, which ensures the concentricity between the disc and the outer platform as described herein. The concentric rotation and assembly of the rotating blade assembly with respect to the outer band, in turn, minimizes the losses that are generated, which ultimately increases the efficiency of the rotating turbine engine when compared to a conventional rotating turbine engine without the rotating blade assembly as described herein.

Further benefits of the present disclosure include a rotating blade assembly within the counter-rotating turbine engine having an increased frictional damping capabilities when compared to a conventional rotating blade assembly used within a counter-rotating turbine engine. For example, conventional rotating blade assemblies can use a monolithic structure interconnecting adjacent blade assemblies. In other words, conventional rotating blade assemblies can include a single inner band, formed as a single unitary piece that is integral with the remainder of the rotating blade assembly. The monolithic structure, however, has low frictional damping capabilities as there is a no contact surface between adjacent components. As such, the conventional rotating blade assembly will vibrate, which in turn increases the total losses associated with the operation of the conventional counter-rotating turbine engine. The counter-rotating turbine engine, as described herein, however, includes a non-monolithic rotating blade assembly. As a non-limiting example, the counter-rotating turbine engine, as described herein, can include a non-monolithic disc that is coupled to and contacts the remainder of the rotating blade assembly along various contact regions generated by the interface between the remainder of the rotating blade assembly and the disc (e.g., the fastener assembly, the ribs, and the tails/sockets). These contact regions can create areas of frictional contact between two adjacent portions in the rotating blade assembly. This, in turn, enhances the frictional damping capabilities of the rotating blade assembly when compared to the conventional rotating blade assembly. This reduces the vibration losses associated with the operation of the counter-rotating turbine engine when compared to the conventional counter-rotating turbine engine, which ultimately increases the overall efficiency of the counter-rotating turbine engine when compared to the conventional counter-rotating turbine engine.

To the extent not already described, the different features and structures of the various aspects can be used in combination with each other as desired. That one feature cannot be illustrated in all of the aspects is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different aspects can be mixed and matched as desired to form new aspects, whether or not the new aspects are expressly described. Combinations or permutations of features described herein are covered by this disclosure.

A rotating blade assembly for a turbine engine having a drive shaft, the rotating blade assembly comprising a disc operably coupled to the drive shaft and including a seat having at least a portion of a first through hole, at least one blade assembly having an upper platform, a lower platform, a dovetail extending from the lower platform, and a blade extending between the upper platform and the lower platform, and a retainer assembly securing the disc to the blade assembly, the retainer assembly comprising a hollow tubular element defining a second through hole, which is aligned with the first through hole, and a pin extending through at least a portion of the second through hole and the first through hole, and confronting at least a portion of the hollow tubular element.

The rotating blade assembly of any preceding clause, wherein the hollow tubular element is an expandable bushing.

The rotating blade assembly of any preceding clause, wherein the pin terminates at a distal end and the rotating blade further comprises a fastener secured to the distal end and abutting the disc.

The rotating blade assembly of any preceding clause, wherein the fastener is one of a nut, a hydraulic fastener, a magnetic fastener, a weld, an adhesive, or an electrical connection.

The rotating blade assembly of any preceding clause, wherein the fastener is the nut and the pin includes a threaded section, wherein the nut is threaded onto the threaded section of the pin.

The rotating blade assembly of any preceding clause, wherein the dovetail defines at least another portion of the first through hole.

The rotating blade assembly of any preceding clause, wherein the disc further comprises a first band and a second band that together define the seat.

The rotating blade assembly of any preceding clause, wherein the first band and the second band are coupled at a lap joint.

The rotating blade assembly of any preceding clause, wherein the first band includes a first rib and the second band includes a second rib, with both the first rib and the second rib confronting a corresponding portion of the dovetail.

The rotating blade assembly of any preceding clause, wherein the retainer assembly further comprises a retainer plate including a through hole aligned with the first through hole and abutting a portion of the disc and the dovetail.

The rotating blade assembly of any preceding clause, wherein hollow tubular element further comprises a first end including a shoulder, with the shoulder abutting a corresponding portion of the retainer plate.

The rotating blade assembly of any preceding clause, wherein the hollow tubular element further comprises a shoulder abutting at least one of the disc or the dovetail.

The rotating blade assembly of any preceding clause, wherein the disc includes a dovetail connection extending from a remainder of the disc in the span-wise direction, and extends through a corresponding portion of the dovetail.

The rotating blade assembly of any preceding clause, wherein the disc extends continuously about the drive shaft 360 degrees.

A gas turbine engine, comprising an engine core defining an engine centerline and comprising drive shaft and a first rotor, and a rotating blade assembly, comprising a disc operably coupled to the drive shaft and including a seat having at least a portion of a first through hole, at least one blade assembly having an upper platform operably coupled to the first rotor, a lower platform, a dovetail extending from the lower platform, and a blade extending between the upper platform and the lower platform, and at least one retainer assembly securing the disc to the at least one blade assembly, the at least one retainer assembly comprising a hollow tubular element defining a second through hole, which is aligned with the first through hole, and a pin extending through at least a portion of the second through hole and the first through hole, and confronting at least a portion of the hollow tubular element.

The gas turbine engine of any preceding clause, wherein the at least one blade assembly is included within a set of blade assemblies circumferentially spaced with respect to one another and that extend circumferentially about an entirety of the engine centerline, and wherein the disc is a 360 degree ring that extends circumferentially about each dovetail of the set of blade assemblies.

The gas turbine engine of any preceding clause, wherein the at least one retainer assembly is included with a set of retainer assemblies, and wherein the set of retainer assemblies are provided along the disc at circumferential positions corresponding to every other blade assembly, and wherein at least two adjacent blade assemblies define a socket extending at least partially through each dovetail, and wherein the disc further comprises a tail extending from the remainder of the disc and at least partially received within the socket.

The gas turbine engine of any preceding clause, further comprising an outer rotor spaced radially outwardly from the first rotor with respect to the engine centerline.

The gas turbine engine of any preceding clause, wherein the disc further comprises a first band including a first rib confronting the dovetail, the first band defining a first portion of the seat, and a second band including a second rib confronting the dovetail, the second band defining a second portion of the seat wherein the first rib and the second rib radially retain the disc to the dovetail.

The gas turbine engine of any preceding clause, wherein the hollow tubular element is an expandable bushing, the expandable bushing further comprising a shoulder abutting at least one of the disc or the dovetail, and wherein the pin terminates at a distal end, the at least one retainer assembly further comprises a retainer plate including a through hole aligned with the first through hole and abutting a portion of the disc and the dovetail, and at least one fastener secured to the distal end and abutting the disc.