Patent Description:
The compressor or turbine sections may include vanes mounted on vane platforms. Seals may be arranged at leading and trailing edges of such components to reduce cooling flow leakage.

<CIT> discloses a prior art vane assembly as set forth in the preamble of claim <NUM>.

<CIT> discloses a prior art multivane segment mounting arrangement for a gas turbine.

In one aspect, there is provided a vane assembly as recited in claim <NUM>.

In another aspect, there is provided a turbine section for a gas turbine engine as recited in claim <NUM>.

<FIG> shows a portion of an example turbine section <NUM>, which may be incorporated into a gas turbine engine such as the one shown in <FIG>. However, it should be understood that other sections of the gas turbine engine <NUM> or other gas turbine engines, and even gas turbine engines not having a fan section at all, could benefit from this disclosure. The turbine section <NUM> includes a plurality of alternating turbine blades <NUM> and turbine vanes <NUM>.

A turbine blade <NUM> has a radially outer tip <NUM> that is spaced from a blade outer air seal assembly <NUM> with a blade outer air seal ("BOAS") <NUM>. The BOAS <NUM> may be mounted to an engine case or structure, such as engine static structure <NUM> via a control ring or support structure <NUM> and a carrier <NUM>. The engine structure <NUM> may extend for a full <NUM>° about the engine axis A.

The turbine vane assembly <NUM> generally comprises a plurality of vane segments <NUM>. In this example, each of the vane segments <NUM> has an airfoil <NUM> extending between an inner vane platform <NUM> and an outer vane platform <NUM>.

<FIG> illustrates an example vane segment <NUM>. The vane segment <NUM> has an outer platform <NUM> radially outward of the airfoil <NUM> and an inner platform <NUM> radially inward of the airfoil <NUM>. Each platform <NUM> has radially inner and outer sides R1, R2, respectively, first and second axial sides A1, A2, respectively, and first and second circumferential sides C1, C2, respectively. The radially inner side R1 faces in a direction toward the engine central axis A. The radially inner side R1 is thus the gas path side of the outer vane platform <NUM> that bounds a portion of the core flow path C. The first axial side A1 faces in a forward direction toward the front of the engine <NUM> (i.e., toward the fan <NUM>), and the second axial side A2 faces in an aft direction toward the rear of the engine <NUM> (i.e., toward the exhaust end). In other words, the first axial side A1 is near the airfoil leading end (or leading edge) <NUM> and the second axial side A2 is near the airfoil trailing end (or trailing edge) <NUM>. The first and second circumferential sides C1, C2 of each platform <NUM> abut circumferential sides C1, C2 of adjacent platforms <NUM>.

Although a vane platform <NUM> is described, this disclosure may apply to other components, and particularly flow path components. For example, this disclosure may apply to combustor liner panels, shrouds, transition ducts, exhaust nozzle liners, blade outer air seals, or other CMC components. In the illustrated example, the example vane segment <NUM> is a singlet, meaning the vane segment <NUM> includes only one airfoil section <NUM>. This disclosure is not limited to singlets, it may be doublets, triplets etc., however. Further, while the example vane segment <NUM> is in the high pressure turbine section <NUM>, one would understand that this disclosure can be used in other sections of the engine <NUM> such as the mid-turbine frame <NUM>. Further, although the outer vane platform <NUM> is generally shown and referenced, this disclosure may apply to the inner vane platform <NUM>.

<FIG>, which falls outside the wording of the claims, illustrates a cross-sectional view of the vane segment <NUM> along the line <NUM>-<NUM> of <FIG>. The segment <NUM> generally includes an outer portion <NUM> and a support structure <NUM>. The support structure <NUM> has a radially extending portion <NUM> and an axially extending portion <NUM>. The support structure <NUM> provides structural support for the vane <NUM>. The radially extending portion <NUM> and the axially extending portion <NUM> may be formed as a single unitary component, for example. The support structure <NUM> may be formed from a metallic material.

The outer portion <NUM> forms the airfoil <NUM> and inner and outer platforms <NUM>, <NUM>. The outer portion <NUM> is arranged within the core flowpath C. That is, the outer portion <NUM> is a portion of the segment <NUM> that is exposed to the core flowpath C. The outer portion <NUM> may be formed of a ceramic matrix composite ("CMC") material. The outer portion <NUM> may formed of a plurality of CMC laminate sheets. The laminate sheets may be silicon carbide fibers, formed into a braided or woven fabric in each layer. In other examples, the outer portion <NUM> may be made of a monolithic ceramic. CMC components such as outer portion <NUM> are formed by laying fiber material, such as laminate sheets or braids, in tooling, injecting a gaseous infiltrant into the tooling, and reacting to form a solid composite component. The component may be further processed by adding additional material to coat the laminate sheets. CMC components may have higher operating temperatures than components formed from other materials.

The outer portion <NUM> may be spaced from the support structure <NUM> to form a gap <NUM> between the outer portion <NUM> and the support structure <NUM>. The gap <NUM> may be used for directing cooling flow, for example. In the illustrated example, cooling flow F flows through the axially extending portion <NUM> of the support <NUM> to cool the vane assembly <NUM>. In this example, a first seal <NUM> and a second seal <NUM> are arranged between the outer portion <NUM> and the support structure <NUM>. The first seal <NUM> is arranged near the leading edge <NUM> and the second seal <NUM> is arranged near the trailing edge <NUM>. The seals <NUM>, <NUM> may be L-seals, for example. In this example, the first seal <NUM> prevents hot gases from the core flowpath C from entering the gap <NUM>, and the second seal <NUM> prevents cooling flow F from leaking from the vane assembly <NUM>.

The outer platform <NUM> of the outer portion <NUM> has a first flange <NUM> and a second flange <NUM>. The first and second flanges <NUM>, <NUM> extend radially into the gap <NUM> between the outer portion <NUM> and the support structure <NUM>. In this example, the first and second flanges <NUM>, <NUM> extend radially outward from the outer portion <NUM> towards the axially extending portion <NUM> of the support structure <NUM>. A clearance <NUM> in the axial direction is formed between the flanges <NUM>, <NUM> and the axially extending portion <NUM>. The clearance <NUM> may be between about <NUM> and about <NUM> inches (<NUM> to <NUM>), for example. The flanges <NUM>, <NUM> partially block the gap <NUM> and help prevent cooling flow leakage and/or hot gas ingestion by creating a torturous path between the support structure <NUM> and the outer portion <NUM>. Although a particular arrangement with flanges <NUM>, <NUM> is shown, the flanges may have a different arrangement, as shown and described below.

<FIG>, which falls outside the wording of the claims, illustrates another arrangement for an example vane assembly <NUM>. In this example, the flanges <NUM>, <NUM> terminate radially inward of the axial portion <NUM> of the support structure <NUM>. In this example, the outer portion <NUM> includes flanges <NUM>, <NUM> that are axially inward of the seals <NUM>, <NUM> relative to the radial portion <NUM> of the support structure <NUM>. In other words, the flange <NUM> near the leading edge <NUM> is aft of the seal <NUM> and the flange <NUM> is forward of the seal <NUM>. In this example, there may be a clearance <NUM> in the radial direction between the flange <NUM> and the axial portion <NUM> of the support structure <NUM>. In one example, the clearance <NUM> may be between about <NUM> and about <NUM> inches (<NUM> to <NUM>), for example. That is, in this example, the flanges <NUM>, <NUM> do not contact the axial portion <NUM> of the support structure <NUM>. The flanges <NUM>, <NUM> do not provide structural support to the assembly in this example. In this example, the flanges <NUM>, <NUM> form a labyrinth flow discourager, and obstruct cooling air from leaking by introducing flow turning with edges and corners of the flanges <NUM>, <NUM>.

<FIG>, which falls outside the wording of the claims, illustrates another arrangement for an example vane assembly <NUM>. In this example, the flanges <NUM>, <NUM> wrap around the axial portion <NUM> of the support structure <NUM>. That is, the flanges <NUM> extend radially outward of the axial portion <NUM>. The first flange <NUM> extends axially forward of the axial portion <NUM>, then curves to face axially aft. The second flange <NUM> extends axially aft of the axial portion <NUM>, then curves to face axially forward. The flanges <NUM>, <NUM> may be integrally formed as part of a CMC preform, or may be formed via machining. The flanges <NUM>, <NUM> may reduce cooling flow leakage by creating a longer and more tortuous flow path for cooling flow leakage.

<FIG> illustrates an arrangement for an example vane assembly <NUM> within the claims. In this example, multiple flanges may be used near the leading and/or trailing edges <NUM>,<NUM>. For example, the leading edge <NUM> includes a forward flange <NUM> that extends radially beyond the axial portion <NUM> and a forward flange <NUM> that terminates radially inward of the axial portion <NUM>. The trailing edge <NUM> includes an aft flange <NUM> that extends radially beyond the axial portion <NUM> and an aft flange <NUM> that terminates radially inward of the axial portion <NUM>. In this example, the flanges <NUM>, <NUM> may extend from the axially extending portion <NUM> of the support structure <NUM>. The flanges
<NUM>, <NUM> may be a metallic material and formed integrally with the support structure <NUM>, for example. This arrangement functions as a labyrinth seal by creating a tortuous flow path for cooling flow leakage.

<FIG>, which falls outside the wording of the claims, illustrates another arrangement for an example vane assembly <NUM>. In this example, the outer portion <NUM> has a flange <NUM> near the leading edge <NUM>, and a different flange <NUM> near the trailing edge <NUM>. The leading and trailing edges <NUM>, <NUM> may have differing sealing needs, and thus different seal and flange arrangements. For example, the seal <NUM> near the leading edge <NUM> may protect primarily against core flow path ingestion, while the seal <NUM> near the trailing edge <NUM> may protect primarily against cooling flow leakage. In the event the seal <NUM> fails, the flange <NUM> creates a tortuous path for hot gases from the core flow path. In the event the seal <NUM> fails, the flange <NUM> creates sharp edges to slow cooling flow leakage. Although a particular flange combination is shown, other leading and trailing edge flange arrangements may be used.

<FIG>, which falls outside the wording of the claims, illustrates a portion of an inner vane platform <NUM>. In this example, the outer portion <NUM> has a forward flange <NUM> and an aft flange <NUM>. The flanges <NUM>, <NUM> extend axially forward and aft, respectively, of a radial portion <NUM> of the support structure <NUM>. At the inner platform <NUM>, if the seal fails, too much cooling flow across the vane may result in unwanted thermal gradients. The flanges <NUM>, <NUM>, <NUM>, <NUM> provide redundant protection to prevent such thermal gradients in the event a seal fails.

The disclosed flange arrangements provide redundant protection against cooling flow leakage or hot gas ingestion. The outer portion <NUM> may be formed from a ceramic material, which has much higher temperature capabilities than the metallic support structure <NUM>. Thus, cooling flow leakage and/or hot gas ingestion may create unwanted thermal gradients or prematurely wear components. The flanges may help to prevent leakage of cooling air or ingestion of hot gases into the gap <NUM> between the support structure <NUM> and the outer portion <NUM> in the event the seals fail. The flanges form a labyrinth flow discourager by obstructing the cooling air from leaking out by turning the flow and introducing sharp edges and corners. These sharp edges and corners slow the flow of leakage, reducing the amount of cooling air that is leaked through the gap.

In this disclosure, "generally axially" means a direction having a vector component in the axial direction that is greater than a vector component in the circumferential direction, "generally radially" means a direction having a vector component in the radial direction that is greater than a vector component in the axial direction and "generally circumferentially" means a direction having a vector component in the circumferential direction that is greater than a vector component in the axial direction.

Claim 1:
A vane assembly (<NUM>), comprising:
a support structure (<NUM>) that is a unitary component having an axial portion (<NUM>) and a radial portion;
an outer portion arranged between the support structure (<NUM>) and a flow path (C), wherein the outer portion defines a gap between the outer portion and the support structure axial portion (<NUM>); and
a flange (<NUM>; <NUM>) extending into the gap,
wherein a seal is arranged in the gap,
wherein the flange (<NUM>; <NUM>) is formed in the outer portion and extends from the outer portion towards the support structure (<NUM>),
characterised in that the assembly (<NUM>) comprises
a second flange (<NUM>; <NUM>) formed in the support structure (<NUM>) and extending from the support structure axial portion (<NUM>) to create a tortuous flow path.