Patent Description:
Turbomachines are utilized in a variety of industries and applications for energy transfer purposes. For example, a gas turbine engine generally includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section progressively increases the pressure of a working fluid entering the gas turbine engine and supplies this compressed working fluid to the combustion section. The compressed working fluid and a fuel (e.g., natural gas) mix within the combustion section and burn in a combustion chamber to generate high pressure and high temperature combustion gases. The combustion gases flow from the combustion section into the turbine section where they expand to produce work. For example, expansion of the combustion gases in the turbine section may rotate a rotor shaft connected, e.g., to a generator to produce electricity. The combustion gases then exit the gas turbine via the exhaust section.

The combustion section of a gas turbine typically includes combustors that are coupled to a stage-one nozzle of the turbine section via transition ducts. Generally, each transition duct has an aft frame positioned adjacent to an inlet side of the turbine section. The aft frame will usually have two arcuate portions which are referred to as inner and outer portions, being inner and outer in the radial direction with respect to the centerline axis of the turbine. The inner and outer portions of the aft frame are interconnected by radially extending linear portions, often referred to as side portions. A sealing assembly is typically used to seal between the aft frame and the inlet of the turbine section. In particular, inner and outer circumferential seals are used to seal between the inner and outer portions of the aft frame and the corresponding inlet of the turbine section. Likewise, radially oriented side seals can be disposed between adjacent aft frames to substantially close and seal off the circumferential gaps between the side portion of one aft frame and the next aft frame.

The sealing assembly positioned about the aft frame generally functions to prevent high temperature combustion gases from being diluted with pressurized air surrounding the combustor prior to entrance into the turbine section. In this way, the sealing assembly ensures that the high temperature combustion gases are utilized fully in order to produce work within the turbine section.

However, issues exist with the use of many known sealing assemblies. For example, the high temperature of the combustion gases can cause damage to the sealing assembly over time, which may result in a limited life and decreased durability of the assembly. In addition, thermal expansion and vibrational movement of the aft frame and the stage one nozzle during operation of the gas turbine can cause the sealing assemblies to misalign and/or entirely decouple from, which results in an incomplete seal between the components.

<CIT> describes a sealing arrangement for sealing between an aft frame of a combustor and a stage-one nozzle of a gas turbine within a high pressure plenum that at least partially surrounds various components of the combustor, the sealing arrangement comprising a seal comprising a flexible sealing element, the flexible sealing element comprising an intermediate portion, a first outer portion on one side of the intermediate portion, and a second outer portion on the other side of the intermediate portion, wherein the intermediate portion is mechanically loaded against the aft frame and the stage-one nozzle. The first outer portion and the second outer portion are pressure-loaded against the aft frame and the stage-one nozzle by a compressed working fluid within the high pressure plenum <CIT> discloses another example of sealing arrangements between the aft frame and the nozzle stage.

Accordingly, an improved sealing assembly is desired in the art. In particular, an improved sealing assembly for a gas turbine engine that has increased durability and alignment, thereby prolonging the overall life and durability of the assembly, is desired.

Aspects and advantages of the sealing arrangements and gas turbines in accordance with the present invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the technology.

In accordance with one embodiment, a sealing arrangement for a gas turbine is provided. The sealing arrangement includes a transition duct having an upstream end and a downstream end. The transition duct includes an aft frame that circumferentially surrounds the downstream end of the transition duct. A stage one nozzle is spaced apart from the aft frame and defines a gap therebetween. A sealing assembly extends across the gap and is magnetically coupled to both the aft frame and the stage one nozzle. The sealing arrangement includes a first magnet magnetically coupled to the aft frame and a second magnet magnetically coupled to the stage one nozzle. The sealing arrangement further includes a shell that is coupled to and at least partially surrounds between the first magnet and the second magnet.

In accordance with another embodiment, a gas turbine is provided. The gas turbine includes a compressor section. The gas turbine also includes a combustor section having a plurality of combustors. Each combustor includes a transition duct having an upstream end and a downstream end. Each transition duct includes an aft frame that circumferentially surrounds the downstream end of the transition duct. The gas turbine also includes a turbine section having a stage one nozzle spaced apart from the aft frame. A gap is defined between the stage one nozzle and the aft frame. A sealing assembly extends across the gap and is magnetically coupled to both the aft frame and the stage one nozzle. The sealing arrangement includes a first magnet magnetically coupled to the aft frame and a second magnet magnetically coupled to the stage one nozzle. The sealing arrangement further includes a shell that is coupled to at least partially surrounds the first magnet and the second magnet.

These and other features, aspects and advantages of the present sealing arrangements and turbomachines will become better understood with reference to the following description and appended claims.

A full and enabling disclosure of the present sealing arrangements and turbomachines, directed to one of ordinary skill in the art, is set forth in the following description, which makes reference to the appended figures, in which:.

As used herein, the terms "upstream" (or "forward") and "downstream" (or "aft") refer to the relative direction with respect to fluid flow in a fluid pathway. The term "radially" refers to the relative direction that is substantially perpendicular to an axial centerline of a particular component, the term "axially" refers to the relative direction that is substantially parallel and/or coaxially aligned to an axial centerline of a particular component and the term "circumferentially" refers to the relative direction that extends around the axial centerline of a particular component. terms of approximation, such as "generally," or "about" include values within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction. For example, "generally vertical" includes directions within ten degrees of vertical in any direction, e.g., clockwise or counter-clockwise.

Referring now to the drawings, <FIG> illustrates a schematic diagram of one embodiment of a turbomachine, which in the illustrated embodiment is a gas turbine <NUM>. Although an industrial or land-based gas turbine is shown and described herein, the present disclosure is not limited to a land based and/or industrial gas turbine unless otherwise specified in the claims.

As shown, gas turbine <NUM> generally includes an inlet section <NUM>, a compressor section <NUM> disposed downstream of the inlet section <NUM>, a plurality of combustors (not shown) within a combustor section <NUM> disposed downstream of the compressor section <NUM>, a turbine section <NUM> disposed downstream of the combustor section <NUM>, and an exhaust section <NUM> disposed downstream of the turbine section <NUM>. Additionally, the gas turbine <NUM> may include one or more shafts <NUM> coupled between the compressor section <NUM> and the turbine section <NUM>.

The compressor section <NUM> may generally include a plurality of rotor disks <NUM> (one of which is shown) and a plurality of rotor blades <NUM> extending radially outwardly from and connected to each rotor disk <NUM>. Each rotor disk <NUM> in turn may be coupled to or form a portion of the shaft <NUM> that extends through the compressor section <NUM>.

The turbine section <NUM> may generally include a plurality of rotor disks <NUM> (one of which is shown) and a plurality of rotor blades <NUM> extending radially outwardly from and being interconnected to each rotor disk <NUM>. Each rotor disk <NUM> in turn may be coupled to or form a portion of the shaft <NUM> that extends through the turbine section <NUM>. The turbine section <NUM> further includes an outer casing <NUM> that circumferentially surrounds the portion of the shaft <NUM> and the rotor blades <NUM>, thereby at least partially defining a hot gas path <NUM> through the turbine section <NUM>.

During operation, a working fluid such as air <NUM> flows through the inlet section <NUM> and into the compressor section <NUM> where the air <NUM> is progressively compressed, thus providing pressurized air or compressed air <NUM> to the combustors <NUM> (<FIG>) of the combustor section <NUM>. The compressed air <NUM> is mixed with fuel <NUM> and burned within each combustor <NUM> (<FIG>) to produce combustion gases <NUM>. The combustion gases <NUM> flow through the hot gas path <NUM> from the combustor section <NUM> into the turbine section <NUM>, wherein energy (kinetic and/or thermal) is transferred from the combustion gases <NUM> to the rotor blades <NUM>, causing the shaft <NUM> to rotate. The mechanical rotational energy may then be used to power the compressor section <NUM> and/or to generate electricity. The combustion gases <NUM> exiting the turbine section <NUM> may then be exhausted from the gas turbine <NUM> via the exhaust section <NUM>.

As shown in <FIG>, a combustor <NUM> may be at least partially surrounded by an outer casing <NUM> such as a compressor discharge casing. The outer casing <NUM> may at least partially define a high-pressure plenum <NUM> that at least partially surrounds various components of the combustor <NUM>, such as transition duct <NUM>. The high-pressure plenum <NUM> may be in fluid communication with the compressor <NUM> (<FIG>) so as to receive the compressed air <NUM> therefrom. As illustrated in <FIG>, the combustor <NUM> may be connected to a stage-one nozzle <NUM> of turbine <NUM> via a transition duct <NUM> including an aft frame <NUM>. The transition duct <NUM> defines a flow path P. Also shown in <FIG> is the central axis A of turbine <NUM>, which defines an axial direction substantially parallel to and/or along axis A, a radial direction R (<FIG>) perpendicular to axis A, and a circumferential direction C (<FIG>) extending around axis A.

Referring now to <FIG>, a pair of circumferentially arranged transition ducts <NUM> are illustrated, each having an upstream end <NUM> and a downstream end <NUM>. As shown, an aft frame <NUM> surrounds the respective downstream end <NUM> of the transition ducts <NUM>. As illustrated in <FIG>, in some embodiments, the aft frame <NUM> may have an inner portion <NUM> and an outer portion <NUM>, with a pair of opposing side portions <NUM> and <NUM> that extend radially between the inner and the outer portions <NUM> and <NUM>. Also illustrated in <FIG> is an inner seal <NUM> and an outer seal <NUM> respectively disposed on the inner portion <NUM> and outer portion <NUM> of each aft frame <NUM>. Aft frame <NUM> may include a notch or slot <NUM> (as shown in <FIG> for receiving inner seal <NUM> and/or outer seal <NUM>. In some embodiments, a notch <NUM> may extend fully around the perimeter of the aft frame <NUM> (e.g., notch <NUM> may be continuous through the side portions <NUM> and <NUM> and the inner and the outer portions <NUM> and <NUM>) for receiving both inner seal <NUM> and outer seal <NUM> as well as a radially-oriented side seal (not shown) which may be provided between adjacent aft frames <NUM>. It is also possible in some embodiments to provide separate slots or notches for each of the seals <NUM>, <NUM>, and <NUM>.

As shown in <FIG>, inner seal <NUM> and outer seal <NUM> may be circumferentially oriented with respect to a circumferential direction C of the gas turbine <NUM>. For example, each inner seal <NUM> is circumferentially aligned with the other inner seal <NUM> on the adjacent aft frame <NUM>, and each outer seal <NUM> is circumferentially aligned with the other outer seal <NUM> on the adjacent aft frame <NUM>. Thus, inner seals <NUM> and outer seals <NUM> may be collectively referred to as circumferentially oriented seals.

In the description herein, certain features of the aft frame <NUM>, stage-one nozzle <NUM>, and seals <NUM> and <NUM>, will be described with reference to one or the other of inner portion <NUM>/inner seal <NUM> and outer portion <NUM>/outer seal <NUM>, nonetheless, it will be recognized by one of ordinary skill in the art that such features can be associated with either or both of inner portions <NUM> and/or outer portions <NUM>.

<FIG> illustrates a cross-sectional view of an exemplary sealing arrangement <NUM> in accordance with embodiments of the present invention. As shown in <FIG>, the sealing arrangement <NUM> includes a transition duct <NUM> having an upstream end <NUM> and a downstream end <NUM> (As shown in <FIG>). In many embodiments, an aft frame <NUM> circumferentially surrounds the downstream end <NUM> of the transition duct <NUM>. A stage one nozzle <NUM> of turbine <NUM> may be spaced apart from the aft frame <NUM> and may define a gap <NUM> between the stage one nozzle <NUM> and the aft frame <NUM>. Specifically, the stage one nozzle <NUM> and the aft frame <NUM> is axially spaced apart to allow for movement and/or thermal expansion of the stage one nozzle <NUM> and/or the aft frame <NUM> during operation of the gas turbine <NUM>. The gap <NUM> may be defined axially between an aft face <NUM> of the aft frame <NUM> and a forward face <NUM> of the stage one nozzle <NUM>.

As shown in <FIG>, the sealing arrangement <NUM> includes a sealing assembly <NUM> that extends across the gap <NUM>, in order to prevent combustion gases <NUM> exiting the transition duct <NUM> from being diluted with pressurized air <NUM> surrounding the combustor <NUM> prior to entrance into the turbine section <NUM>. In various embodiments, the sealing assembly <NUM> may be an inner seal <NUM>, an outer seal <NUM>, or both an inner seal <NUM> and an outer seal <NUM>. According to the invention, the sealing assembly includes a first magnet <NUM> magnetically coupled to the aft frame <NUM>, a second magnet <NUM> magnetically coupled to the stage one nozzle <NUM>, and a shell <NUM> coupled to the first magnet <NUM> and the second magnet <NUM>.

As shown in <FIG>, the sealing arrangement includes a first magnet <NUM> and a second magnet <NUM>. The first magnet <NUM> is magnetically coupled to the aft frame <NUM> via an attractive magnetic force, and the second magnet <NUM> is magnetically coupled to the stage one nozzle <NUM> via an attractive magnetic force.

For example, in some embodiments, the aft frame <NUM> and/or the stage one nozzle <NUM> may be formed of a ferrous (or iron containing) metal, such that the aft frame <NUM> and/or the stage one nozzle <NUM> are attracted to the magnets <NUM>, <NUM> and coupled thereto. In other embodiments, the aft frame <NUM> and/or the stage one nozzle <NUM> may be formed of a non-ferrous metal, such that they are not impacted by magnetic forces. In such embodiments, as shown in <FIG>, the sealing arrangement <NUM> may further include a third magnet <NUM> embedded within the aft frame <NUM>, and a fourth magnet <NUM> embedded within the stage one nozzle <NUM>. As shown, the first magnet <NUM> may be magnetically coupled to the third magnet <NUM>, and the second magnet <NUM> may be magnetically coupled to the fourth magnet <NUM>.

In many embodiments, the magnets <NUM>, <NUM>, <NUM>, <NUM> may each include a first pole or north pole N and a second pole or south pole S. As is generally understood by those of skill in the art, the ends of a permanent magnet (such as the magnets <NUM>, <NUM>, <NUM>, <NUM> described herein), are called its poles. One end is called the north pole, the other is called the south pole. If two magnets are oriented such the south pole of one faces the north pole of the other, the magnets will exhibit a force that pulls the magnets toward one other. Similarly, if two magnets are oriented such that two like poles are facing one another, the magnets will exhibit a force that repels the magnets away from one another. Although the magnets <NUM>, <NUM>, <NUM>, <NUM> are shown in <FIG> as having the poles labeled on specific ends, it is envisioned to be within the scope of the present disclosure that each of the poles may be switched, thereby yielding the same configuration but with an opposite magnetic pole orientation.

In many embodiments, each of the magnets <NUM>, <NUM>, <NUM>, <NUM> may be in the form of a piece of metal material that has its component atoms so ordered that the material exhibits properties of magnetism, such as attracting other iron-containing objects or aligning itself in an external magnetic field. In exemplary embodiments, the magnets <NUM>, <NUM>, <NUM>, <NUM> may be Alnico magnets, such that they are permanent magnets that are primarily made up of a combination of aluminum, nickel, and cobalt but may also include copper, iron and titanium. Alnico magnets may be capable of operation in extremely high temperatures, such as upwards of <NUM>°F.

As shown in <FIG>, The first magnet <NUM> may extend generally axially from a first end <NUM> that is magnetically coupled to the aft frame <NUM> to a second free end <NUM>. The first end <NUM> of the first magnet <NUM> may be magnetically coupled to the third magnet <NUM>, such that the first end <NUM> of the first magnet <NUM> directly contacts the third magnet <NUM> and is attracted thereto via an attractive magnetic force. For example, as shown in <FIG>, the first end <NUM> of the first magnet <NUM> may be the south pole S, which may be attracted to the north pole N of the third magnet <NUM>. Similarly, the second magnet <NUM> may extend generally axially from a first end <NUM> that is magnetically coupled to the stage one nozzle <NUM> to a second free end <NUM>. The first end <NUM> of the second magnet <NUM> may be magnetically coupled to the fourth magnet <NUM>, such that the first end <NUM> of the second magnet <NUM> directly contacts the fourth magnet <NUM> and is attracted thereto via an attractive magnetic force. For example, as shown in <FIG>, the first end <NUM> of the second magnet <NUM> may be the south pole S, which may be attracted to the north pole N of the fourth magnet <NUM>.

As shown in <FIG> the first magnet <NUM> and the second magnet <NUM> may be axially separated from each other, such that there is an axial gap <NUM> defined between the first magnet <NUM> and the second magnet <NUM>. Specifically, the axial gap <NUM> may be defined between the second free end <NUM> of the first magnet <NUM> and the second free end <NUM> of the second magnet <NUM>.

In exemplary embodiments, the first magnet <NUM> may face the second magnet <NUM> such that a repulsive magnetic force repels the first magnet <NUM> and the second magnet <NUM> away from one another in an axial direction A. For example, the second free ends <NUM> and <NUM> of each of the respective magnets <NUM> and <NUM> may have like poles, thereby exhibiting a repulsive force on one another. For example, as shown in <FIG>, both the second free end <NUM> of the first magnet <NUM> and the second free end <NUM> of the second magnet may face one another and may both be the north pole N, thereby producing a repelling force between one another.

In many embodiments, the first magnet <NUM> and the second magnet <NUM> may each include a first portion <NUM> and a second portion <NUM>. The first portion <NUM> may extend between the respective first ends <NUM>, <NUM> and a respective transition segment <NUM> disposed between the first portion <NUM> and the second portion <NUM>. Likewise, each of the second portions <NUM> may extend from the respective transition segments <NUM> to the respective second free ends <NUM>, <NUM>. As shown, the first portion <NUM> may define a first width <NUM> and the second portion <NUM> may define a second width <NUM>. As shown in <FIG>, the second width <NUM> may be larger than the first width <NUM>, such that the transition segment <NUM> defines a groove <NUM> disposed between the first portion <NUM> and the second portion <NUM> of the magnets <NUM>, <NUM>. For example, the magnets <NUM>, <NUM> may taper from the first width <NUM> to the second width <NUM>, such that the groove <NUM> is defined on both the radially inner side and the radially outer side of the magnets <NUM>, <NUM>.

According to the invention, the shell <NUM> is coupled to and at least partially surrounding the first magnet <NUM> and the second magnet <NUM>. In many embodiments, the shell <NUM> may extend between the first magnet <NUM> and the second magnet <NUM>, in order for the sealing assembly <NUM> to completely cover the gap <NUM> and the axial gap <NUM>, thereby preventing the combustion gases <NUM> from being diluted with pressurized air <NUM> surrounding the combustor <NUM> prior to entrance into the turbine section <NUM>. As shown in <FIG>, the shell <NUM> may include a radially outer portion <NUM> and a radially inner portion <NUM>. Although the embodiment in <FIG> is shown having both a radially outer portion <NUM> and a radially inner portion <NUM> of the shell <NUM>, in other embodiments (not shown), the shell <NUM> may only include a radially inner portion <NUM> or only a radially outer portion <NUM>.

The radially outer portion <NUM> of the shell <NUM> may couple to the groove <NUM> of the first magnet <NUM> and the groove <NUM> of the second magnet <NUM> on the radially outer side of the magnets <NUM>, <NUM>. Similarly, the radially inner portion <NUM> of the shell <NUM> may couple to the groove <NUM> of the first magnet <NUM> and the groove <NUM> of the second magnet <NUM> on the radially inner side of the magnets <NUM>, <NUM>. In some embodiments, the shell <NUM> may be slidably coupled to the first magnet <NUM> and the second magnet <NUM>, such that axial movement of the aft frame <NUM> and or stage one nozzle <NUM> would result in the shell <NUM> sliding in the axial direction relative to the first magnet <NUM> and the second magnet <NUM>. In other embodiments, the shell <NUM> may be fixedly coupled to the first magnet <NUM> and the second magnet <NUM>, such that axial movement of the aft frame <NUM> and the stage one nozzle <NUM> would result in the shell <NUM> bending and/or flexing.

In various embodiments, the shell <NUM> may be composed of a flexible sealing element, such as a metallic cloth material. For example, the flexible sealing element may be a woven mesh cloth of a suitable metal material, e.g., alloy L605. The materials of the flexible sealing element may be layered, e.g., a single sheet of cloth material, may be folded over on itself, and/or multiple layers of cloth material may be welded together.

In particular embodiments, the sealing assembly <NUM> may further include a heat shield <NUM>. As shown in <FIG>, the heat shield <NUM> may extend axially from the groove <NUM> on the radially inner side of the second magnet <NUM> to the stage one nozzle <NUM>. In various embodiments, the heat shield <NUM> may be positioned at least partially radially between the radially inner portion <NUM> of the shell <NUM> and the second magnet <NUM>. The heat shield <NUM> may function to advantageously prevent combustion gases <NUM> exiting the aft frame <NUM> from causing thermal damage to magnets <NUM>, <NUM>. For example, the heat shield <NUM> creates an additional barrier between the high temperature combustion gases <NUM> and the magnets <NUM>, <NUM>, which prolongs the life and durability of the magnets <NUM>, <NUM>.

In some embodiments, the shell <NUM> may define one or more cooling holes <NUM>, <NUM>. For example, a cooling hole <NUM> may be defined within the radially outer portion <NUM> of the shell <NUM>, and a cooling hole <NUM> may be defined within the radially inner portion <NUM>. The cooling holes <NUM>, <NUM> may function to allow a small portion of the pressurized air <NUM> to flow therethrough and cool the various components of the sealing assembly <NUM>, such as the first magnet <NUM>, the second magnet <NUM>, the shell <NUM>, and/or other components.

As shown in <FIG>, the aft frame <NUM> may define a slot <NUM> that extends axially and circumferentially within the aft frame <NUM> with respect to the axial centerline of the gas turbine <NUM>. In many embodiments, at least a portion of the sealing assembly <NUM> extends into the slot <NUM> defined by the aft frame <NUM>, which advantageously shields the sealing assembly from the high temperature combustion gases <NUM>.

In various embodiments, the aft frame <NUM> may define a cooling channel <NUM> that functions to cool various components of the sealing arrangement <NUM>. As shown, the cooling channel <NUM> may extend along the aft frame <NUM>. In many embodiments, the cooling channel <NUM> may diverge radially inward towards the axial centerline A of the gas turbine <NUM> in the direction of combustion gas <NUM> flow within the aft frame <NUM> (from upstream end to downstream end). The cooling channel <NUM> may further include an outlet <NUM>. The outlet <NUM> may be oriented generally radially, in order to direct a flow of cooling air <NUM> towards the sealing assembly <NUM>. The flow of cooling air <NUM> may provide for impingement cooling to the various components of the sealing assembly <NUM>, such as the first magnet <NUM>, the second magnet <NUM>, the shell <NUM>, and/or other components. The flow of cooling air <NUM> may ensure that the various magnets <NUM>, <NUM> within the sealing assembly <NUM> maintain an operable temperature, i.e., ensure that the magnets <NUM>, <NUM> do not overheat.

<FIG> illustrates a view of a sealing arrangement from along a radial direction R, in which the shell <NUM> is shown as a dashed line, in accordance with embodiments of the present disclosure. As shown in <FIG>, the first magnet <NUM> may be a plurality of first magnets <NUM> circumferentially neighboring each other along the aft frame <NUM>. For example, each first magnet <NUM> may be positioned between, and capable of relative movement to, two neighboring first magnets <NUM>. Similarly, the second magnet <NUM> may be a plurality of second magnets <NUM> circumferentially neighboring each other along the stage one nozzle. For example, each second magnet <NUM> of the plurality of second magnets <NUM> may be positioned between, and capable of relative movement to, two neighboring second magnets <NUM>. Including a plurality of first magnets <NUM> and second magnets <NUM> as shown in <FIG> allows the sealing assembly <NUM> to attach to a non-flat surface, i.e. surfaces that include protrusions, bumps, or contours. For example, as shown, the stage one nozzle <NUM> may include a contour <NUM>, and the plurality of second magnets <NUM> may adjust and move relative to one another to couple to the surface of the stage one nozzle <NUM>.

In particular embodiments, the plurality of first magnets <NUM> and the plurality of second magnets <NUM> may each comprise a trapezoidal cross-sectional shape. For example, the plurality of first magnets <NUM> may be arranged such that the trapezoidal cross-sectional shape alternates in orientation. That is, as shown, each of the first magnets <NUM> may include sides <NUM> that taper in the axial direction A, e.g., the first magnets <NUM> may taper such that they increase in circumferential width in the axial direction A or decrease in circumferential width in the axial direction A. Alternatively or additionally, in other embodiments (not shown), the sides <NUM> of the first magnets <NUM> may taper in the radial direction R, such that the first magnets <NUM> increase in circumferential width in the radial direction R or decrease in circumferential width in the radial direction R.

In many embodiments, a first magnet <NUM> that includes sides <NUM> that taper in a first direction (either increasing in width or decreasing in width) may be immediately neighboring, and in contact with, two other first magnets <NUM> having sides <NUM> that taper in a second direction that is opposite the first direction. Arranging the plurality of first magnets <NUM> in this way advantageously limits the relative movement between the magnets <NUM> and prevents them from moving too far and causing a misalignment of the sealing assembly <NUM>.

Similarly, the plurality of second magnets <NUM> may be arranged such that the trapezoidal cross-sectional shape alternates in orientation. That is, each of the second magnets <NUM> may include sides <NUM> that taper in the axial direction A, e.g., the second magnets <NUM> may taper such that they increase in circumferential width in the axial direction A or decrease in circumferential width in the axial direction A. Alternatively or additionally, in other embodiments (not shown), the sides <NUM> of the second magnets <NUM> may taper in the radial direction R, such that the first magnets <NUM> increase in circumferential width in the radial direction R or decrease in circumferential width in the radial direction R.

In many embodiments, a second magnet <NUM> that includes sides <NUM> that taper in a first direction (either increasing in width or decreasing in width) may be immediately neighboring, and in contact with, two other second magnets <NUM> having sides <NUM> that taper in a second direction that is opposite the first direction. Arranging the plurality of second magnets <NUM> in this way advantageously limits the relative movement between the magnets <NUM> and prevents them from moving too far and causing a misalignment of the sealing assembly <NUM>.

In many embodiments, the sealing assembly <NUM> may extend continuously in the circumferential direction C. In such embodiments, the shell <NUM> may extend continuously in the circumferential direction (into and out of the page in <FIG>, such that the combustion gases <NUM> are prevented from being diluted <NUM> degrees around the gas turbine <NUM>.

In operation, combustion gases <NUM> may exit the combustor <NUM> via the aft frame <NUM> and have to traverse across the gap <NUM> prior to entrance into the turbine section <NUM> via the stage one nozzle <NUM>. The sealing assembly <NUM> described herein may ensure that no combustion gases <NUM> escape before entering the turbine section. In this way, the sealing assembly <NUM> ensures that all of the thermal energy from the combustion gases <NUM> gets received and utilized by the turbine. The arrangement of the magnets <NUM>, <NUM>, <NUM>, <NUM> described herein advantageously allows for relative movement between the aft frame <NUM> and the stage one nozzle <NUM> while maintaining a proper seal across the gap <NUM>. For example, the sealing assembly <NUM> of the invention is capable of moving and rotating along with the aft frame <NUM> and stage one nozzle <NUM>, while the magnets <NUM>, <NUM>, <NUM>, <NUM> ensure that the sealing assembly <NUM> maintains alignment.

Claim 1:
A sealing arrangement (<NUM>) for a gas turbine, comprising:
a transition duct (<NUM>) of a combustor
having an upstream end (<NUM>) and a downstream end (<NUM>), the transition duct (<NUM>) comprising an aft frame (<NUM>) that circumferentially surrounds the downstream end (<NUM>) of the transition duct (<NUM>); and
a stage one nozzle (<NUM>) spaced apart from the aft frame (<NUM>) and defining a gap (<NUM>) therebetween;
characterized by:
a sealing assembly (<NUM>) extending across the gap (<NUM>) and magnetically coupled to both the aft frame (<NUM>) and the stage one nozzle (<NUM>), the sealing assembly (<NUM>) comprising:
a first magnet (<NUM>) magnetically coupled to the aft frame (<NUM>);
a second magnet (<NUM>) magnetically coupled to the stage one nozzle (<NUM>); and
a shell (<NUM>) coupled to and at least partially surrounding the first magnet (<NUM>) and the second magnet (<NUM>).