Patent Description:
A typical gas turbine engine includes seal assemblies to seal gaps between stationary and rotating components. One such known seal assembly includes a stationary carbon seal element that contacts a rotating seal land. Rubbing friction between the stationary carbon seal element and the rotating seal land subjects both the stationary carbon seal element and the rotating seal land to relatively high temperatures and, thus, thermal stresses and fatigue. Various techniques are known in the art for cooling such a seal assembly. While these known cooling techniques have various advantages, there is still room in the art for improvement.

According to an aspect of the present invention a seal assembly according to claim <NUM> is provided for a gas turbine.

This assembly includes a guide rail, a translating device and a fluid coupling device. The guide rail is configured with a rail fluid passage. The translating device is mated with and axially translatable along the guide rail. The translating device is configured with a translating device fluid passage. The fluid coupling device is mounted to and axially slidable along the guide rail. The fluid coupling device is configured with a coupling device fluid passage adapted to direct fluid from the rail fluid passage to the translating device fluid passage. The fluid coupling is adapted to move radially relative to the translating device.

The guide rail may be configured as a guide pin.

The assembly may include a seal element mounted to the translating device. The translating device may be configured as a seal carrier.

The seal element may be configured with a seal element fluid passage adapted to receive the fluid from the translating device fluid passage.

<FIG> is a partial side sectional illustration of an assembly <NUM> for a gas turbine engine. This engine assembly <NUM> includes a rotating element <NUM>, a bearing <NUM> and a seal assembly <NUM>.

The rotating element <NUM> is rotatable about an axial centerline <NUM>, which centerline <NUM> may be an axial centerline of the gas turbine engine. The rotating element <NUM> of <FIG> is configured as a tubular engine shaft. However, in other embodiments, the rotating element <NUM> may be configured as another component (e.g., a sleeve) mounted to and rotatable with an engine shaft, or any other rotor within the gas turbine engine.

The bearing <NUM> is configured to rotatably support the rotating element <NUM> relative to a static structure <NUM>; e.g., an engine case, a strut assembly, etc. The bearing <NUM> may be configured as a roller element bearing. The bearing <NUM> of <FIG>, for example, includes an annular outer race <NUM>, an annular inner race <NUM> and a plurality of bearing elements <NUM>; e.g., cylindrical or spherical elements. The outer race <NUM> circumscribes the inner race <NUM> and the bearing elements <NUM>. The outer race <NUM> is mounted to the static structure <NUM>. The inner race <NUM> circumscribes and is mounted to the rotating element <NUM>. The bearing elements <NUM> are arranged in an annular array about the axial centerline <NUM>, which array is radially between and engaged with the outer race <NUM> and the inner race <NUM>. The present disclosure, of course, is not limited to the foregoing exemplary bearing configuration. For example, in other embodiments, the bearing may be configured as a journal bearing or any other type of bearing utilized in the gas turbine engine.

The seal assembly <NUM> is configured to seal an annular gap between a rotating assembly and the static structure <NUM>, which rotating assembly includes at least the rotating element <NUM>. The seal assembly <NUM> of <FIG>, for example, is configured to seal the gap which extends (e.g., radially and/or axially) between the static structure <NUM> and the rotating element <NUM>. Of course, in other embodiments, the seal assembly <NUM> may seal a gap extending between the static structure <NUM> and another rotating component mounted to and/or rotatable with the rotating element <NUM>.

The seal assembly <NUM> of <FIG> includes an annular seal land <NUM> and an annular seal element <NUM>; e.g., a carbon seal element. The seal assembly <NUM> of <FIG> also includes one or more guide rails <NUM> and a seal support assembly <NUM>.

The seal land <NUM> is configured with a full hoop body that extends circumferentially about the axial centerline <NUM>. The seal land <NUM> extends axially along the axial centerline <NUM> between an axial first end <NUM> and an axial second end <NUM>. The seal land <NUM> extends radially between a radial inner side <NUM> and a radial outer side <NUM>.

The seal land <NUM> includes an annular, radially extending seal land surface <NUM> located at (e.g., on, adjacent or proximate) the axial second end <NUM>. This seal land surface <NUM> may be an uninterrupted surface. The seal land surface <NUM>, for example, may be a flat planar surface configured without circumferential and/or radial interruptions such as, but not limited to, channels, slots and apertures. Of course, in other embodiments, the seal land surface <NUM> may be circumferentially and/or radially interrupted by one or more channels, slots, apertures and/or other types of surface interruptions.

Referring to <FIG>, the annular seal element <NUM> is configured with a full hoop body that extends circumferentially about the axial centerline <NUM>. This full hoop body may be a single unitary body; e.g., a monolithic body. Alternatively, the full hoop body may be a segmented body; e.g., the seal element <NUM> may be configured from an array of arcuate seal element segments. The seal element <NUM> extends axially along the axial centerline <NUM> between an axial first end <NUM> and an axial second end <NUM>. The seal element <NUM> extends radially between a radial inner side <NUM> and a radial outer side <NUM>.

The seal element <NUM> includes an annular, radially extending seal element surface <NUM> located at (e.g., on, adjacent or proximate) the axial first end <NUM>. This seal element surface <NUM> may be an uninterrupted surface. The seal element surface <NUM>, for example, may be a flat planar surface configured without circumferential and/or radial interruptions such as, but not limited to, channels, slots and apertures. Of course, in other embodiments, the seal element surface <NUM> may be circumferentially and/or radially interrupted by one or more channels, slots, apertures and/or other types of surface interruptions.

The seal element <NUM> is configured with an internal seal element fluid passage <NUM>. This fluid passage <NUM> includes / is formed by one or more passageways <NUM> through the seal element <NUM>; see also <FIG>. These passageways <NUM> may be located circumferentially about the axial centerline <NUM> in an annular array as shown in <FIG>. Referring again to <FIG>, each passageway <NUM> includes / is formed by an inlet portion <NUM> and an outlet portion <NUM> connected to the inlet portion <NUM> at a corner; e.g., an elbow. The inlet portion <NUM> is an aperture (e.g., a hole, groove, or some other form of passageway) that may extend axially along the axial centerline <NUM> partially into the seal element <NUM> from the axial second end <NUM> to the outlet portion <NUM>. The outlet portion <NUM> is an aperture (e.g., a hole, groove, or some other form of passageway) that may extend radially, relative to the axial centerline <NUM>, partially into the seal element <NUM> from the radial outer side <NUM> to the inlet portion <NUM>.

Referring to <FIG>, the guide rails <NUM> are arranged circumferentially about the axial centerline <NUM> in an annular array. Referring to <FIG>, each of the guide rails <NUM> may be configured as or otherwise include a guide pin. For example, each guide rail <NUM> of <FIG> may have, but is not limited to, a generally cylindrical body <NUM> that extends axially between an axial first end <NUM> and an axial second end <NUM>. An annular flange <NUM> may project out from and circumscribe body <NUM>. An axial first portion <NUM> of the body <NUM>, axially between the axial first end <NUM> and the flange <NUM>, may be configured with a smooth cylindrical surface <NUM>. An axial second portion <NUM> of the body <NUM>, axially between the axial second end <NUM> and the flange <NUM>, may be configured with threads; e.g., the portion <NUM> is a threaded portion.

At least one of the guide rails <NUM> is configured with an internal guide rail fluid passage <NUM>; e.g., a pin fluid passage. This fluid passage <NUM> includes / is formed by a (e.g., single) passageway <NUM> through the guide rail <NUM>. The passageway <NUM> includes / is formed by a bore <NUM> and an aperture <NUM> (e.g., a hole). The bore <NUM> extends axially partially into the guide rail <NUM> from the axial second end <NUM>. The aperture <NUM> projects out from and is thereby fluidly coupled with the bore <NUM>. The aperture <NUM> extends radially through a sidewall of the guide rail <NUM> to an outlet <NUM> in the cylindrical surface <NUM>. Note, in some embodiments, the guide rail <NUM> may be configured with more than one aperture <NUM>.

Referring to <FIG>, the seal support assembly <NUM> is configured to translate axially along the guide rails <NUM>. The seal support assembly <NUM> is also configured to support and provide fluid to the seal element <NUM>. The seal support assembly <NUM> of <FIG> includes a seal carrier <NUM> and at least one fluid coupling device <NUM>.

Referring to <FIG>, the seal carrier <NUM> is configured with a full hoop body that extends circumferentially about the axial centerline <NUM>; see also <FIG>. The seal carrier <NUM> extends axially along the axial centerline <NUM> between an axial first end <NUM> and an axial second end <NUM>. The seal carrier <NUM> extends radially, relative to the axial centerline <NUM>, between a radial inner side <NUM> and a radial outer side <NUM>.

The seal carrier <NUM> of <FIG> includes a tubular base <NUM> and one or more flanges <NUM>. The base <NUM> is configured with an annular recess / notch <NUM>. This recess <NUM> extends axially partially into the base <NUM> from the axial first end <NUM> to an axial end surface <NUM>. The recess <NUM> extends radially partially into the base <NUM> from the radial inner side <NUM> to a radial end surface <NUM>. The recess <NUM> forms a receptacle <NUM> for the seal element <NUM> as described below in further detail.

The base <NUM> is configured with one or more seal carrier fluid passages <NUM> and <NUM>. The first carrier fluid passage <NUM> includes / is formed by at least one passageway <NUM> through the base <NUM>. This passageway <NUM> includes / is formed by at least one first aperture <NUM> (e.g., a hole), at least one second aperture <NUM> (e.g., a hole) and a slot <NUM>. The first aperture <NUM> extends radially partially into the base <NUM> from an outer surface <NUM> of the base <NUM>. This first aperture <NUM> is configured to form a receptacle <NUM> for the fluid coupling device <NUM> as described below in further detail. The second aperture <NUM> extends axially within the base <NUM> between the first aperture <NUM> and the slot <NUM>. The second aperture <NUM> thereby fluidly couples the first aperture <NUM> to the slot <NUM>. The slot <NUM> is located in the axial end surface <NUM>. This slot <NUM> may be an annular slot (e.g., see <FIG>), which extends circumferentially around the centerline <NUM>.

The second carrier fluid passage <NUM> includes / is formed by one or more passageways <NUM> through the base <NUM>. These passageways <NUM> may be located circumferentially about the axial centerline <NUM> in an annular array as shown in <FIG>. Referring again to <FIG>, each passageway <NUM> includes / is formed by an aperture <NUM> (e.g., a hole) and a slot <NUM>. The slot <NUM> may be shared by all of the passageways <NUM>; e.g., each passageway <NUM> includes a circumferential portion of the slot <NUM>. The slot <NUM> is located in the radial end surface <NUM>. This slot <NUM> may be an annular slot, which extends circumferentially around the centerline <NUM>. The aperture <NUM> extends radially into the base <NUM> to the slot <NUM> from the outer surface <NUM> and thereby is fluidly coupled with the slot <NUM>.

Referring to <FIG>, the flanges <NUM> are arranged circumferentially about the base <NUM>. Each flange <NUM> includes a slot <NUM>.

Referring to <FIG>, the fluid coupling device <NUM> includes a sleeve <NUM> (e.g., a linear hydrostatic bearing) and a tube <NUM> (e.g., a jumper tube). The sleeve <NUM> is configured as a tubular sleeve body <NUM>. The sleeve body <NUM> extends axially between an axial first end <NUM> and an axial second end <NUM>. The sleeve body <NUM> extends radially, relative to an axis <NUM> of the sleeve <NUM>, between a radial inner side <NUM> and a radial outer side <NUM>, where the axis <NUM> may be parallel to the centerline <NUM>. The radial inner side <NUM> of the sleeve <NUM> forms a bore <NUM> that extends axially through the fluid coupling device <NUM> and its sleeve <NUM>.

The tube <NUM> may be configured as a tubular projection. The tube <NUM> projects radially, relative to the axis <NUM> of the sleeve <NUM>, out from the radial outer side <NUM> of the sleeve <NUM> to a distal end <NUM>.

The fluid coupling device <NUM> is configured with at least one coupling device fluid passage <NUM>. This fluid passage <NUM> includes / is formed by a (e.g., single) passageway <NUM> through the fluid coupling device <NUM>. This passageway <NUM> includes / is formed by a slot <NUM> and an aperture <NUM> (e.g., a hole). The slot <NUM> is located in the sleeve <NUM> at its radial inner side <NUM>. The slot <NUM> extends partially axially within the sleeve <NUM> and may extend either fully circumferentially or partially circumferentially about the axis <NUM> of the sleeve <NUM>. The aperture <NUM> projects out from the slot <NUM> and extends through the sleeve <NUM> and the tube <NUM> to an outlet <NUM> at the distal end <NUM>. In this embodiment, an outer portion of the aperture <NUM> forms a bore of the tube <NUM>.

Referring to <FIG>, the seal land <NUM> is arranged with the rotating element <NUM> in such a manner so as to be rotatable with the rotating element <NUM> about the axial centerline <NUM>. The seal land <NUM> of <FIG>, for example, circumscribes and is fixedly mounted to the rotating element <NUM>.

The guide rails <NUM> are fixedly mounted to the static structure <NUM>. For example, the threaded portion <NUM> of each guide rail <NUM> may be screwed into a corresponding tapped hole in the static structure <NUM>.

The seal element <NUM> is seated in the receptacle <NUM> of the seal carrier <NUM>. A split ring <NUM> and/or another device secures the seal element <NUM> within the receptacle <NUM> such that the seal element <NUM> is fixedly mounted to the seal carrier <NUM>. Of course, the seal element <NUM> may also or alternatively be mounted to the seal carrier <NUM> using other fastening and/or bonding techniques. The seal element fluid passage <NUM> is fluidly coupled with and between the first and the second seal carrier fluid passages <NUM> and <NUM>. More particularly, a fluid interface is formed between the passage <NUM> slot and the passage <NUM> apertures and a fluid interface is formed between the passage <NUM> apertures and the passage <NUM> slot.

The tube <NUM> is seated in the receptacle <NUM> of the seal carrier <NUM>. More particularly, the tube <NUM> projects radially, relative to the axial centerline <NUM>, into the receptacle <NUM> to its distal end <NUM> (see <FIG>). The elements <NUM> and <NUM> may be configured such that there is a relatively tight fit between those elements <NUM> and <NUM> in order to form a seal interface therebetween. An annular ring seal <NUM> may also or alternatively be arranged between the tube <NUM> and the seal carrier <NUM>.

The fluid coupling device <NUM> is mated with / slidably mounted on a respective one of the guide rails <NUM> - the guide rail <NUM> with the internal rail fluid passage <NUM>. In particular, the guide rail <NUM> is inserted through the bore of the sleeve <NUM> such that a cylindrical surface <NUM> at the radial inner side of the sleeve <NUM> engages the cylindrical surface <NUM> of the guide rail <NUM>. The surfaces <NUM> and <NUM> may be configured (e.g., sized) such that there is a relatively tight fit between the elements <NUM> and <NUM> in order to form a seal interface therebetween. The coupling fluid passage <NUM> is fluidly coupled with the guide rail fluid passage <NUM>. More particularly, a fluid interface is formed between the passage <NUM> aperture and the passage <NUM> slot.

The seal carrier <NUM> is mated with the guide rails <NUM>. In particular, each of the guide rails <NUM> projects through a respective flange slot <NUM>; see also <FIG>.

One or more spring elements <NUM> may be arranged between the static structure <NUM> and the seal carrier <NUM>. These spring elements <NUM> are configured to bias the seal carrier <NUM> and, thus, the seal element <NUM> away from the static structure <NUM> and towards the seal land <NUM>. In particular, the spring elements <NUM> cause the surfaces <NUM> and <NUM> to axially sealingly engage (e.g., contact) one another.

During operation of the assembly <NUM> of <FIG>, fluid (e.g., lubricant and/or coolant) flows through the fluid passages <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. In particular, the fluid flows sequentially through the fluid passages174, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> and is discharged into a bearing compartment <NUM> for collection in a bearing compartment sump. Heat energy may be transferred from the seal element <NUM> into the fluid as the fluid travels through the seal element fluid passage <NUM>. The flow of the fluid through the seal element <NUM> may thereby cool the seal element <NUM> during operation and, thus, mitigate heat related stresses and degradation of the seal element <NUM> cause by rubbing friction between the elements <NUM> and <NUM>.

In order to accommodate engine vibrations and differential thermal expansion between the components <NUM> and <NUM>, the seal carrier <NUM> and the fluid coupling device <NUM> are each adapted to move (e.g., translate) axially along the guide rail(s) <NUM>. In addition, the fluid coupling device <NUM> moves radially relative to the seal carrier <NUM> to accommodate radial movements / shifting of the seal carrier <NUM> relative to the guide rails <NUM>.

The assembly <NUM> is described above as including a single fluid coupling device <NUM> for ease of description. However, in other embodiments, the assembly <NUM> may include one or more additional fluid coupling devices <NUM> such that a plurality or all of the guide rails <NUM> is associated with a respective fluid coupling device <NUM>. The number of fluid coupling devices <NUM> included may be selected based on the cooling requirements of the seal element <NUM>. In such embodiments, the fluid passage <NUM> includes a plurality of the apertures <NUM>; e.g., see dashed aperture <NUM> in <FIG>.

In some embodiments, the assembly <NUM> may also include one or more secondary seals. For example, the assembly of <FIG> includes an annular secondary seal element <NUM> axially between the seal element <NUM> and the seal carrier <NUM>. This secondary seal element <NUM> is configured to separate cooling fluids from boundary fluids.

<FIG> is a side cutaway illustration of a geared turbine engine <NUM> with which the assembly <NUM> may be configured. The turbine engine <NUM> extends along an axial centerline (e.g., the centerline <NUM>) between an upstream airflow inlet <NUM> and a downstream airflow exhaust <NUM>. The turbine engine <NUM> includes a fan section <NUM>, a compressor section <NUM>, a combustor section <NUM> and a turbine section <NUM>. The compressor section <NUM> includes a low pressure compressor (LPC) section 185A and a high pressure compressor (HPC) section 185B. The turbine section <NUM> includes a high pressure turbine (HPT) section 187A and a low pressure turbine (LPT) section 187B.

The engine sections <NUM>-<NUM> are arranged sequentially along the centerline <NUM> within an engine housing <NUM>. This housing <NUM> includes an inner case <NUM> (e.g., a core case) and an outer case <NUM> (e.g., a fan case). The inner case <NUM> may house one or more of the engine sections <NUM>-<NUM>; e.g., an engine core. The outer case <NUM> may house at least the fan section <NUM>.

Each of the engine sections <NUM>, 185A, 185B, 187A and 187B includes a respective rotor <NUM>-<NUM>. Each of these rotors <NUM>-<NUM> includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed, adhered and/or otherwise attached to the respective rotor disk(s).

The fan rotor <NUM> is connected to a gear train <NUM>, for example, through a fan shaft <NUM>. The gear train <NUM> and the LPC rotor <NUM> are connected to and driven by the LPT rotor <NUM> through a low speed shaft <NUM>. The HPC rotor <NUM> is connected to and driven by the HPT rotor <NUM> through a high speed shaft <NUM>. The shafts <NUM>-<NUM> are rotatably supported by a plurality of bearings <NUM>; e.g., rolling element and/or thrust bearings. Each of these bearings <NUM> is connected to the engine housing <NUM> by at least one stationary structure such as, for example, an annular support strut. The rotating element <NUM> of <FIG> may be configured as any one of the shafts <NUM>-<NUM> and the bearing <NUM> of <FIG> may be configured as any one of the bearings <NUM>.

During operation, air enters the turbine engine <NUM> through the airflow inlet <NUM>. This air is directed through the fan section <NUM> and into a core gas path <NUM> and a bypass gas path <NUM>. The core gas path <NUM> extends sequentially through the engine sections 185A-187B. The air within the core gas path <NUM> may be referred to as "core air". The bypass gas path <NUM> extends through a bypass duct, which bypasses the engine core. The air within the bypass gas path <NUM> may be referred to as "bypass air".

The assembly <NUM> may be included in various turbine engines other than the one described above. The assembly <NUM>, for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the assembly <NUM> may be included in a turbine engine configured without a gear train. The assembly <NUM> may be included in a geared or non-geared turbine engine configured with a single spool, with two spools (e.g., see <FIG>), or with more than two spools. The turbine engine may be configured as a turbofan engine, a turbojet engine, a propfan engine, a pusher fan engine or any other type of turbine engine. The present disclosure therefore is not limited to any particular types or configurations of turbine engines.

Claim 1:
A seal assembly (<NUM>) for a gas turbine engine (<NUM>), comprising:
a guide rail (<NUM>) configured with a rail fluid passage (<NUM>);
a translating device (<NUM>) mated with and axially translatable along the guide rail (<NUM>), the translating device (<NUM>) configured with a translating device fluid passage (<NUM>, <NUM>); and
a fluid coupling device (<NUM>) mounted to and axially slidable along the guide rail (<NUM>),
characterised in that
the fluid coupling device (<NUM>) is configured with a coupling device fluid passage (<NUM>) adapted to direct fluid from the rail fluid passage (<NUM>) to the translating device fluid passage (<NUM>, <NUM>);
wherein the fluid coupling device (<NUM>) is adapted to move radially relative to the translating device (<NUM>).