Patent Description:
Rotational equipment typically includes one or more seal assemblies for sealing gaps between rotors and stators. A typical seal assembly includes a contact seal with a seal element such as a knife edge seal that engages a seal land. Such a contact seal, however, can generate a significant quantity of heat which can reduce efficiency of the rotational equipment as well as subject other components of the rotational equipment to high temperatures. To accommodate the high temperatures, other components of the rotational equipment may be constructed from specialty high temperature materials, which can significantly increase the manufacturing and servicing costs of the rotational equipment. While non-contact seals have been developed in an effort to reduce heat within rotational equipment, such non-contact seals can be difficult to configure within the rotational equipment. Such non-contact seals and associated components (e.g., shafts, linkages, etc.) may also need to be replaced when incidental contact occurs.

There is a need in the art for improved seal assemblies for rotational equipment.

<CIT> discloses features of the preamble of claim <NUM>, and <CIT> (which discloses an assembly according to the preamble of appended claim <NUM>) and <CIT> disclose other assemblies for rotational equipment.

According to an aspect of the present disclosure, an assembly is provided as claimed in claim <NUM>.

The base may be configured with a monolithic full hoop body.

A carrier may be included that connects the non-contact seal to the stator. The carrier may be configured with a monolithic full hoop body.

The seal portion of the linkage is radially thicker than adjacent portions of the linkage.

The stator may be configured with a monolithic full hoop body.

The stator may be configured as or include a fairing configured to form an axial portion of an inner peripheral boundary of a core gas path through the rotational equipment. The rotational equipment may be configured as a gas turbine engine.

A plurality of first rotor blades may be included and arranged around and connected to the first rotor disk. A plurality of second rotor blades may be included and arranged around and connected to the second rotor disk. A plurality of stator vanes may be included and arranged around and connected to the stator. The stator vanes may be axially between the first rotor blades and the second rotor blades.

The linkage may include a flange connector attached to the second rotor disk with one or more fasteners. The flange connector may have an outermost radius. The non-contact seal may have an innermost radius that is greater than the outermost radius.

The linkage may have an outermost radius and the non-contact seal has an innermost radius that is greater than the outermost radius.

A portion of the linkage may be configured to pass through the non-contact seal during assembly.

The linkage may be configured to partially pass axially through the non-contact seal during assembly.

A carrier may be included which mounts the base to the fairing. The carrier may be configured with a monolithic full hoop body.

The fairing may be configured with a monolithic full hoop body. The base may be configured with a monolithic full hoop body.

A portion of the linkage which forms the cylindrical surface is radially thicker than axially adjacent portions of the linkage.

The portion of the linkage has a hardface which forms the cylindrical surface.

The seal portion of the linkage is radially thicker by an additional thickness than adjacent portions of the linkage. The hardface provides a portion of the additional thickness and forms the cylindrical surface.

<FIG> is a side cutaway illustration of a gas turbine engine <NUM> for an aircraft propulsion system. This turbine engine <NUM> is configured as a geared turbofan engine, and extends along an axial 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 19A and a high pressure compressor (HPC) section 19B. The turbine section <NUM> includes a high pressure turbine (HPT) section 21A and a low pressure turbine (LPT) section 21B.

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), and may be housed within an inner nacelle / inner fixed structure (not shown) which provides an aerodynamic cover for the inner case <NUM>. The inner case <NUM> may be configured with one or more axial and/or circumferential inner sub-casings; e.g., case segments. The outer case <NUM> may house at least the fan section <NUM>, and may be housed within an outer nacelle (not shown) which provides an aerodynamic cover for the outer case <NUM>. Briefly, the outer nacelle along with the outer case <NUM> overlaps the inner nacelle thereby defining a bypass gas path <NUM> radially between the nacelles. The outer case <NUM> may be configured with one or more axial and/or circumferential outer case segments.

Each of the engine sections <NUM>-19B, 21A and 21B 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). Each of the rotors <NUM>-<NUM> may also include one or more rotor disk linkages, which interconnect adjacent rotor disks within the respective rotor.

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> (e.g., the inner case <NUM>) by at least one stationary structure such as, for example, an annular support strut.

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 the bypass gas path <NUM>. The core gas path <NUM> extends sequentially through the engine sections <NUM>-<NUM>. The air within the core gas path <NUM> may be referred to as "core air". The air within the bypass gas path <NUM> may be referred to as "bypass air".

<FIG> illustrates an assembly <NUM> for the turbine engine <NUM>. This turbine engine assembly <NUM> includes an assemblage of stator elements <NUM>-<NUM>, a rotor <NUM> and one or more non-contact seal assemblies <NUM>.

The assemblage of stator elements includes a turbine engine case <NUM>, one or more arrays <NUM> of stators vanes <NUM> and one or more stators <NUM>. The turbine engine case <NUM> may be configured as part of the inner case <NUM>. For example, the turbine engine case <NUM> of <FIG> is configured as an axial tubular sub-casing (e.g., segment) of the inner case <NUM>, which houses at least some (or alternatively all) of the HPC rotor <NUM>.

Referring to <FIG>, the turbine engine case <NUM> may be configured having one or more monolithic full hoop bodies <NUM>. Herein, the term "monolithic" may describe a component which is formed as a single unitary body. The turbine engine case <NUM>, for example, includes a plurality of integral, tubular bodies <NUM>, where each body <NUM> is formed without any mechanically interconnected axial and/or circumferential segments. Note, in some embodiments, a monolithic body may include one or more bodies bonded together. For example, a metal band may be formed into a hoop and its opposing ends may be welded and/or otherwise bonded together. In another example, arcuate segments (e.g., halves) may be respectively bonded together to form a full hoop body. The assembly <NUM> of the present disclosure, however, is not limited to the foregoing exemplary turbine engine case configuration. For example, in other embodiments, the turbine engine case <NUM> may be configured with a single full hoop body or as a circumferentially segmented body.

Referring to <FIG>, each array <NUM> of stator vanes <NUM> includes a plurality of stator vanes <NUM>. These stator vanes <NUM> are arranged circumferentially around the centerline <NUM> and radially between the rotor <NUM> and the turbine engine case <NUM>. Each of the stator vanes <NUM> extends radially from a respective one of the stators <NUM> to the turbine engine case <NUM>.

Each of the stator vanes <NUM> of <FIG> is configured as a fixed stator vane. Herein, the term "fixed stator vane" may describe a stator vane which is fixedly attached to its respective stator and/or the turbine engine case <NUM>. The present disclosure, however, is not limited to any particular type or configuration of stator vanes <NUM>. For example, in alternative embodiments, one or more or all of the stator vanes <NUM> in one or more of the arrays <NUM> may each be configured as a variable stator vane. Herein, the term "variable stator vane" may describe a stator vane which may pivot about an axis, which extends generally radially out from a centerline of an engine.

Each of the stators <NUM> is or includes a fairing configured to form an axial portion of an inner peripheral boundary of the core gas path <NUM>. The stator <NUM> (e.g., fairing) of <FIG> is configured having a monolithic full hoop body. This stator <NUM>, for example, is formed as an integral, tubular body without any mechanically interconnected axial and/or circumferential segments. The assembly <NUM> of the present disclosure, however, is not limited to the foregoing exemplary stator configuration. For example, in other embodiments, the stator <NUM> may be configured as an axially and/or circumferentially segmented body.

Referring to <FIG>, the rotor <NUM> may be configured as or included in one of the rotors <NUM>-<NUM> (see <FIG>); e.g., the HPC rotor <NUM>. This rotor <NUM> includes one or more arrays <NUM> of rotor blades <NUM>, one or more rotor disks <NUM> (e.g., 90A, 90B, 90C) and one or more annular rotor disk linkages <NUM> (e.g., 92A, 92B). Each array <NUM> of rotor blades <NUM> includes a plurality of rotor blades, which are arranged circumferentially around and connected to the respective rotor disk <NUM>. Each array of rotor blades <NUM> is positioned axially between neighboring arrays <NUM> of stator vanes <NUM>.

Each of the linkages <NUM> is configured to connect respective neighboring rotor disks <NUM> to one another. The linkage 92A of <FIG>, for example, extends axially between and is connected to a respective adjacent pair of the rotor disks 90A and 90B. Of course, in other embodiments, one or more of the linkages <NUM> may connect the rotor disk <NUM> to another component of the turbine engine <NUM> such as, for example, the high speed shaft.

Referring still to <FIG>, the linkage 92A may be formed integral with or bonded (e.g., welded, etc.) to the first rotor disk 90A at a first end of the linkage 92A. The linkage <NUM> may be removably attached to the second rotor disk 90B at a second end of the linkage 92A. The linkage 92A of <FIG>, for example, is attached to the second rotor disk 90B with one or more fasteners <NUM>. More particularly, the linkage 92A of <FIG> includes a flange connector 95A, which is mechanically fastened to the rotor disk 90A with a plurality of bolts <NUM> and nuts <NUM>. The linkage <NUM> of the present disclosure, however, may also or alternatively be attached to the second rotor disk 90B using one or more connections other than the exemplary bolted connection described above. Furthermore, while the first end of the linkage <NUM> is shown in <FIG> as being upstream of the second end, these ends and their respective connections may be reversed as generally shown, for example, in <FIG>.

One or more parts <NUM>, 95A, 98A and 98B of the linkage <NUM> (or the whole of the linkage 92A as shown in <FIG>) has an outermost radius <NUM> which is sized less than an innermost radius <NUM> of the non-contact seal assembly <NUM> (e.g., the non-contact seal). In this manner, those parts <NUM>, <NUM> and 98B of the linkage <NUM> may be inserted into and passed axially through the seal assembly <NUM> during assembly of the rotor <NUM>. In the exemplary embodiment shown in <FIG>, the parts of the linkage 92A includes an intermediate seal portion <NUM> and adj acent end portions 98A and 98B of the linkage 92A as well as the flange connector 95A. Of course, in other embodiments as shown in <FIG>, at least one of the parts of the linkage <NUM> (e.g., the end portion 98A) which need not be passed through the seal assembly <NUM> during assembly may have an outermost radius which is greater than the innermost radius <NUM>.

Referring now to <FIG>, the seal portion <NUM> may have an outer cylindrical surface <NUM>. Herein, the term "cylindrical" may describe a surface or part with a circular-annular cross-sectional geometry which extends substantially (e.g., only) axially along a centerline. In contrast, a "conical" surface or part may also extend in a radial direction towards or away from the centerline. Referring still to <FIG>, this seal portion <NUM> may, not according to the invention, have substantially the same radial thickness as one or more other portions of the linkage <NUM>; e.g., the portions.

Referring to <FIG>, the seal portion <NUM> is radially thicker than one or more adjacent portions 98A and 98B of the linkage <NUM>. This additional thickness (e.g., seal region <NUM>) is provided by forming a hardface on a base portion of the linkage <NUM>, where the hardface forms the cylindrical surface <NUM>. In another example, the hardface may by formed on the buildup of material, wherein the hardface material has a hardness value different than and harder than the base linkage material. This hardface material may be the same material as the base linkage material where, for example, that portion of the material is (e.g., heat) treated to increase its hardness. Alternatively, the hardface material may be different than the base linkage material beneath.

The seal portion <NUM> of <FIG> has an axial length <NUM> that is greater than its radial thickness <NUM>. In general, the axial length <NUM> is greater than an axial length of the non-contact seal assembly <NUM>. With the foregoing configuration of <FIG>, the linkage <NUM> may accommodate infrequent periodic contact with a respective one of the non-contact seal assemblies <NUM>, where such contact may wear away the material of the linkage <NUM>. This additional thickness may reduce internal stress concentrations within the linkage material caused by wear from periodic contact with the assembly <NUM>. Furthermore, the additional thickness of the seal region <NUM> may be restored during a rebuild process by filling in wear grooves with additional material and/or removing some or all of the worn seal region <NUM> and forming a new seal region <NUM> in its place without compromising the linkage base portion beneath. This in turn may prolong the useful life of the linkage <NUM>. The hardface may also provide a barrier to prevent incidental wear from progressing into a crack in the linkage <NUM>.

Referring to <FIG> and <FIG>, each of the seal assemblies <NUM> is arranged in a radial gap between a respective one of the stators <NUM> and a respective one of the linkages <NUM>. Each of the seal assemblies <NUM> is configured to substantially seal the respective gap. The seal assembly <NUM> of <FIG> and <FIG>, for example, includes an annular carrier <NUM> and an annular non-contact seal <NUM> such as, but not limited to, a hydrostatic non-contact seal.

The carrier <NUM> is configured to mount the non-contact seal <NUM> to the respective stator <NUM>. The carrier <NUM> may be configured having a monolithic full hoop body. The carrier <NUM>, for example, is formed as an integral, tubular body without any mechanically interconnected axial and/or circumferential segments. The assembly <NUM> of the present disclosure, however, is not limited to the foregoing exemplary carrier configuration. For example, in other embodiments, the carrier <NUM> may be configured as an axially and/or circumferentially segmented body.

Referring to <FIG>, the non-contact seal <NUM> includes one or more circumferentially spaced shoes <NUM> which are located in a non-contact position along the cylindrical surface <NUM> of the respective linkage <NUM>. Each shoe <NUM> is formed with a sealing surface <NUM> and a slot <NUM> extending radially inwardly toward the sealing surface <NUM>.

Under some operating conditions, particularly at higher pressures, it may be desirable to limit the extent of radial movement of the shoes <NUM> with respect to the rotor <NUM> to maintain tolerances; e.g., the spacing between the shoes <NUM> and the cylindrical surface <NUM>. The non-contact seal <NUM> includes one or more circumferentially spaced spring elements <NUM>, the details of one of which are best seen in <FIG> and <FIG>. Each spring element <NUM> is formed with an inner band <NUM> and an outer band <NUM> radially outwardly spaced from the inner band <NUM>. One end of each of the bands <NUM> and <NUM> is mounted to or integrally formed with a stationary base <NUM> of the seal and the opposite end thereof is connected to a first stop <NUM>. This base <NUM> may be configured as a monolithic full hoop body as best seen in <FIG>. Of course, the present disclosure is not limited to the aforesaid exemplary configuration.

The first stop <NUM> includes a strip <NUM> which is connected to a shoe <NUM> (one of which is shown in <FIG>), and has an arm <NUM> opposite the shoe <NUM> which may be received within a recess <NUM> formed in the base <NUM>. The recess <NUM> has a shoulder <NUM> positioned in alignment with the arm <NUM> of the first stop <NUM>.

A second stop <NUM> is connected to or integrally formed with the strip <NUM> and is connected to the shoe <NUM>. The second stop <NUM> is circumferentially spaced from the first stop <NUM> in a position near the point at which the inner and outer bands <NUM> and <NUM> connect to the base <NUM>. The second stop <NUM> is formed with an arm <NUM> which may be received within a recess <NUM> in the base <NUM>. The recess <NUM> has a shoulder <NUM> positioned in alignment with the arm <NUM> of second stop <NUM>.

During operation, aerodynamic forces may be developed which apply a fluid pressure to the shoe <NUM> causing it to move radially with respect to the respective linkage <NUM>. The fluid velocity increases as the gap <NUM> between the shoe <NUM> and respective linkage <NUM> increases, thus reducing pressure in the gap <NUM> and drawing the shoe <NUM> radially inwardly toward the rotor <NUM>. As the seal gap <NUM> closes, the velocity decreases and the pressure increases within the seal gap <NUM> thus forcing the shoe <NUM> radially outwardly from the rotor <NUM>. The spring elements <NUM> deflect and move with the shoe <NUM> to create a primary seal of the circumferential gap <NUM> between the rotor <NUM> and base <NUM> within predetermined design tolerances. The first and second stops <NUM> and <NUM> may limit the extent of radially inward and outward movement of the shoe <NUM> with respect to the rotor <NUM> for safety and operational limitation. A gap is provided between the arm <NUM> of first stop <NUM> and the shoulder <NUM>, and between the arm <NUM> of second stop <NUM> and shoulder <NUM>, such that the shoe <NUM> can move radially inwardly relative to the rotor <NUM>. Such inward motion is limited by engagement of the arms <NUM>, <NUM> with shoulders <NUM> and <NUM>, respectively, to prevent the shoe <NUM> from contacting the rotor <NUM> or exceeding design tolerances for the gap between the two. The arms <NUM> and <NUM> also contact the base <NUM> in the event the shoe <NUM> moves radially outwardly relative to the rotor <NUM>, to limit movement of the shoe <NUM> in that direction.

The non-contact seal <NUM> is also provided with a secondary seal which may take the form of a brush seal <NUM>, as shown in <FIG>, or a stack of at least two sealing elements oriented side-by-side and formed of thin sheets of metal or other suitable material as shown in <FIG> and <FIG>. The brush seal <NUM> is positioned so that one end of its bristles <NUM> extends into the slot <NUM> formed in the shoe <NUM>. The bristles <NUM> deflect with the radial inward and outward movement of the shoe <NUM>, in response to the application of fluid pressure as noted above, in such a way as to create a secondary seal of the gap <NUM> between the rotor <NUM> and base <NUM>.

Referring now to <FIG> and <FIG>, the secondary seal of this embodiment may include a stack of at least two sealing elements <NUM> and <NUM>. Each of the sealing elements <NUM> and <NUM> includes an outer ring <NUM> formed with a plurality of circumferentially spaced openings <NUM>, a spring member <NUM> mounted within each opening <NUM> and a plurality of inner ring segments <NUM> each connected to at least one of the spring members <NUM>. The spring member <NUM> is depicted in <FIG> as a series of connected loops, but it should be understood that spring member <NUM> could take essentially any other form, including parallel bands as in the spring elements <NUM>. The sealing elements <NUM> and <NUM> are oriented side-by-side and positioned so that the inner ring segments <NUM> extend into the slot <NUM> formed in the shoe <NUM>. The spring members <NUM> deflect with the radial inward and outward movement of the shoe <NUM>, in response to the application of fluid pressure as noted above, in such a way as to create a secondary seal of the gap <NUM> between the rotor <NUM> and base <NUM>. As such, the sealing elements <NUM> and <NUM> assist the spring elements <NUM> in maintaining the shoe <NUM> within design clearances relative to the rotor <NUM>.

One or more of the spring elements <NUM> and <NUM> may be formed of sheet metal or other suitable flexible, heat-resistant material. The sealing elements <NUM> and <NUM> may be attached to one another, such as by welding and/or any other bonding technique, a mechanical connection or the like, or they may positioned side-by-side within the slot <NUM> with no connection between them. In order to prevent fluid from passing through the openings <NUM> in the outer ring <NUM> of each sealing element <NUM> and <NUM>, adjacent sealing elements are arranged so that the outer ring <NUM> of one sealing element <NUM> covers the openings <NUM> in the adjacent sealing element <NUM>. Although not required, a front plate <NUM> may be positioned between the spring element <NUM> and the sealing element <NUM>, and a back plate <NUM> may be located adjacent to the sealing element <NUM> for the purpose of assisting in supporting the sealing elements <NUM>, <NUM> in position within the shoe <NUM>.

During operation, the non-contact seal <NUM> is subjected to aerodynamic forces as a result of the passage of air along the surface of the shoes <NUM> and the respective linkage <NUM> and, more particularly, the respective seal portion <NUM>. The operation of non-contact seal <NUM> is dependent, in part, on the effect of these aerodynamic forces tending to lift the shoes <NUM> radially outwardly relative to the surface of rotor <NUM>, and the counteracting forces imposed by the spring elements <NUM> and the secondary seals (e.g., brush seal <NUM> or the stacked seal formed by plates <NUM>, <NUM>) which tend to urge the shoes <NUM> in a direction toward the rotor <NUM>. These forces acting on the shoe <NUM> are schematically depicted with arrows in <FIG>. These forces acting on the non-contact seal <NUM> may be balanced to ensure that nominal clearance is maintained.

The present disclosure is not limited to the exemplary non-contact seal <NUM> described above. Various other non-contact seals are known in the art and may be reconfigured in light of the disclosure above to be included with the assembly <NUM> of the present disclosure. An example of such an alternative non-contact seal <NUM> is illustrated in <FIG>. Other examples of non-contact seals are disclosed in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>. Still another example of a non-contact seal is a hydrodynamic non-contact seal.

The assembly <NUM> may be included in various aircraft and industrial turbine engines other than the one described above as well as in other types of rotational equipment; e.g., wind turbines, water turbines, rotary engines, etc. 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 invention therefore is not limited to any particular types or configurations of turbine engines or rotational equipment.

Claim 1:
An assembly for rotational equipment, the assembly comprising:
a stator (<NUM>);
a rotor (<NUM>) extending axially along a centerline (<NUM>), the rotor (<NUM>) including a linkage (92A), a first rotor disk (90A), and a second rotor disk (90B), wherein the linkage (92A) extends axially from the first rotor disk (90A) to the second rotor disk (90B); and
a seal assembly (<NUM>) including a hydrostatic non-contact seal (<NUM>),
wherein the seal assembly (<NUM>) is configured for sealing a gap radially between the stator (<NUM>) and the linkage (92A),
wherein the non-contact seal (<NUM>) is positioned directly radially above and is axially aligned with a cylindrical surface (<NUM>) of a seal portion (<NUM>) of the linkage (92A), and
wherein the non-contact seal comprises:
an annular base (<NUM>);
a plurality of shoes (<NUM>) arranged around and radially adjacent the linkage (92A); and
a plurality of spring elements (<NUM>), each of the spring elements (<NUM>) radially between and connecting a respective one of the shoes (<NUM>) to the base (<NUM>),
characterised in that:
the linkage (92A) is removably attached to the second rotor disk (90B), and
the seal portion (<NUM>) of the linkage (92A) has a hardface which forms the cylindrical surface (<NUM>), wherein the seal portion (<NUM>) of the linkage (92A) is radially thicker by an additional thickness than adjacent portions of the linkage (92A), wherein the hardface provides a portion of the additional thickness.