Patent Description:
Gas turbine engines are rotary-type combustion turbine engines built around a power core made up of a compressor, combustor and turbine, arranged in flow series with an upstream inlet and downstream exhaust. The compressor compresses air from the inlet, which is mixed with fuel in the combustor and ignited to generate hot combustion gas. The turbine extracts energy from the expanding combustion gas, and drives the compressor via a common shaft. Energy is delivered in the form of rotational energy in the shaft, reactive thrust from the exhaust, or both.

The individual compressor and turbine sections in each spool are subdivided into a number of stages, which are formed of alternating rows of rotor blade and stator vane airfoils. The airfoils are shaped to turn, accelerate and compress the working fluid flow, or to generate lift for conversion to rotational energy in the turbine.

The combustor section includes a combustor where combustion takes place. In a gas turbine engine, the combustor is fed high pressure air by the compressor section. The combustor then heats this air at constant pressure. After heating, air passes from the combustor section through the turbine section (vanes and rotating blades). A combustor must contain and maintain stable combustion despite very high air flow rates. To do so combustors are carefully designed to first mix and ignite the air and fuel, and then mix in more air to complete the combustion process. Combustors play a crucial role in determining many operating characteristics of a gas turbine engine, such as fuel efficiency, levels of emissions, and transient response (i.e., the response to changing conditions such as fuel flow and air speed).

In typical gas turbine engine arrangements, the combustor is supported by an on-board injector. Such support is typically accomplished by a tab which bolts a combustor inner aft support shell and the on-board injector with contact between the combustor and a first vane of a turbine section through conformal seals. The use of an aft combustor tab typically requires use of a seal between the combustor shell and the first vane/on-board injector to reduce air leakage at these interfaces. Although such design may provide weight efficiencies from a compact design perspective, there may be various drawbacks to such configurations. Accordingly, improved coupling and mounting of a combustor in gas turbine engines may be advantageous.

A prior art turbomachine having the features of the preamble to claim <NUM> is disclosed in <CIT>. Other prior art turbomachines are disclosed in <CIT>, <CIT>, <CIT>, and <CIT>.

According to one aspect of the present invention, there is provided a combustor mounting structure for a gas turbine engines as claimed in claim <NUM>.

Further embodiments of the combustor mounting structures may include that the shell portion is part of a combustor shell.

Further embodiments of the combustor mounting structures may include that combustor mounting structure is configured to fixedly engage with at least one of a diffuser case and an on-board injector of the gas turbine engine, and the central axis is an engine central longitudinal axis.

Further embodiments of the combustor mounting structures may include that each strut of the plurality of struts includes a geometry such that the shell portion and the combustor connection element are offset in an axial direction along the central axis passing through the center of the inner and outer rings.

Further embodiments of the combustor mounting structures may include that the combustor connection element comprises one or more mounting apertures configured to enable mounting of the combustor mounting structure within the gas turbine engine.

According to another aspect of the present invention, there is provided a gas turbine engine as claimed in claim <NUM>.

Further embodiments of the gas turbine engines may include that the shell portion is part of a combustor shell of the combustor.

Further embodiments of the gas turbine engines may include an on-board injector arranged radially inward from the first vane.

Further embodiments of the gas turbine engines may include that the combustor mounting structure is configured to fixedly engage with at least one of the diffuser case and the on-board injector.

Further embodiments of the gas turbine engines may include a fastener configured to fixedly connect the combustor connection element of the combustor mounting structure, the diffuser case, and the on-board injector.

Further embodiments of the gas turbine engines may include that each strut of the plurality of struts has a geometry configured to provide flexibility or relative movement between the shell portion and the combustor connection element.

Further embodiments of the gas turbine engines may include that each strut of the plurality of struts includes a geometry such that the shell portion and the combustor connection element are offset in an axial direction along the engine central longitudinal axis passing through the center of the inner and outer rings.

Further embodiments of the gas turbine engines may include that the combustor connection element comprises one or more mounting apertures configured to enable mounting of the combustor mounting structure within the gas turbine engine.

It should be understood, however, the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.

The following descriptions are by way of example only and should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: The subject matter is particularly pointed out and distinctly claimed at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which like elements may be numbered alike and:.

Detailed descriptions of one or more embodiments of the disclosed apparatus and/or methods are presented herein by way of exemplification and not limitation with reference to the Figures.

Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines.

The exemplary engine <NUM> generally includes a low speed spool <NUM> and a high speed spool <NUM> mounted for rotation about an engine central longitudinal axis Ax relative to an engine static structure <NUM> via several bearing systems <NUM>.

The inner shaft <NUM> can be connected to the fan <NUM> through a speed change mechanism, which in exemplary gas turbine engine <NUM> is illustrated as a geared architecture <NUM> to drive the fan <NUM> at a lower speed than the low speed spool <NUM>. The inner shaft <NUM> and the outer shaft <NUM> are concentric and rotate via bearing systems <NUM> about the engine central longitudinal axis Ax which is collinear with their longitudinal axes.

In a further example, the engine <NUM> bypass ratio is greater than about six (<NUM>), with an example embodiment being greater than about ten (<NUM>), the geared architecture <NUM> is an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about <NUM> and the low pressure turbine <NUM> has a pressure ratio that is greater than about five (<NUM>). In one disclosed embodiment, the engine <NUM> bypass ratio is greater than about ten (<NUM>:<NUM>), the fan diameter is significantly larger than that of the low pressure compressor <NUM>, and the low pressure turbine <NUM> has a pressure ratio that is greater than about five (<NUM>:<NUM>). The geared architecture <NUM> may be an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about <NUM>:<NUM>. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans.

Although the gas turbine engine <NUM> is depicted as a turbofan, it should be understood that the concepts described herein are not limited to use with the described configuration, as the teachings may be applied to other types of engines such as, but not limited to, turbojets, turboshafts, and turbofans wherein an intermediate spool includes an intermediate pressure compressor ("IPC") between a low pressure compressor ("LPC") and a high pressure compressor ("HPC"), and an intermediate pressure turbine ("IPT") between the high pressure turbine ("HPT") and the low pressure turbine ("LPT").

As discussed above, a combustor of the combustor section may be supported by an on-board injector (e.g., a tangential on-board injector or "TOBI"). For example, turning to <FIG>, a schematic illustration of a typical gas turbine engine configuration is shown. In <FIG>, a portion of a gas turbine engine <NUM> is illustratively shown. The gas turbine engine <NUM> includes a compressor section <NUM>, a combustor section <NUM>, and a turbine section <NUM>. The sections <NUM>, <NUM>, <NUM> of the gas turbine engine <NUM> are housed within an engine case <NUM> and are arranged along an engine central longitudinal axis Ax. The compressor section <NUM> can provide compressed or high pressure air to a combustor <NUM> of the combustor section <NUM>. The high pressure air will be mixed with fuel and ignited within the combustor <NUM> and directed toward and into the turbine section <NUM>. The hot, combusted gas will first interact with a first vane <NUM> of the turbine section <NUM>.

The combustor <NUM> includes a shell <NUM> that is mounted to, at least, a diffuser case <NUM> at a flange connection <NUM>. The flange connection <NUM> fixedly connects the shell <NUM> of the combustor <NUM>, an inner portion of the diffuser case <NUM>, and an on-board injector <NUM>. As shown, the flange connection <NUM> is located at a forward end (along the engine central longitudinal axis Ax) of the first vane <NUM> and slightly radially inward therefrom. The flange connection <NUM> bolts or otherwise fastens the combustor inner aft support shell (shell <NUM>) to the on-board injector <NUM>. Furthermore, there is contact between the combustor <NUM> and the first vane <NUM> through seals (e.g., conformal seals) along a gas path. For example, the use of an aft-combustor tab to join at the flange connection <NUM> typically requires use of a seal between the shell <NUM>, the first vane <NUM>, and the on-board injector <NUM> to reduce air leakage at the interface between the components.

Although there are benefits to this type of configuration (e.g., weight efficiency from a compact design), there may be drawbacks as well. For example, inclusion of the necessary seals results in additional components that are subject to the environment, and thus may wear, fatigue, and/or fail. Wear of the seal can cause loss of bolt preload which can cause both release of part of the seal and/or the bolt itself, which can result in Domestic Object Damage (DOD) in the engine. Further, wear of the seal can result in air loss from an ineffective seal.

Accordingly, embodiments of the present disclosure are directed to a configuration of gas turbine engine components that can eliminate the use of seals at a junction between a combustor section and a turbine section. In accordance with embodiments of the present disclosure, a ring-strut-ring design is provided to connect a combustor shell to a flange or other connection. For example, without limitation, twelve struts may be equally spaced about a circumference of the engine to connect the combustor shell to a flange that is removed from the first vane of the turbine section. As such, a combustor support to the inner diffuser case and an on-board injector ("OBI") flange may be moved radially inward, which adds weight but ensures a tight diffuser-combustor-OBI flange connection independent of the conformal seal wear.

Turning now to <FIG>, a schematic illustration of a portion of a gas turbine engine <NUM> is shown. The gas turbine engine <NUM> may be similar to that shown and described above, with various features omitted for clarity and ease of discussion. The gas turbine engine <NUM> includes, as shown, a combustor section <NUM> and a turbine section <NUM> located aft of the combustor section <NUM> along an engine central longitudinal axis Ax. The combustor section <NUM> includes a combustor <NUM> having a combustor shell <NUM> and the turbine section <NUM> includes a first vane <NUM>. The combustor <NUM> is arranged within, in part, a diffuser case <NUM> and the first vane <NUM> is arranged and mounted to, in part, an on-board injector ("OBI") <NUM> (e.g., a tangential on-board injector). The combustor shell <NUM>, the diffuser case <NUM>, and the on-board injector <NUM> are fixedly connected or joined at a connection structure <NUM>.

As shown, the connection structure <NUM> is located inboard or radially inward (toward the engine central longitudinal axis Ax) relative to the combustor <NUM> and the first vane <NUM>. The connection structure <NUM> comprises a diffuser case connection element <NUM>, a combustor connection element <NUM>, and an OBI connection element <NUM> that are joined or connected by a fastener <NUM>. To enable the inboard or radially inward location of the connection structure <NUM>, the combustor connection element <NUM> is arranged apart from a shell portion <NUM> of combustor shell <NUM> by a strut <NUM>. The shell portion <NUM>, the combustor connection element <NUM>, and the strut <NUM> form a combustor mounting structure. The strut <NUM> extends radially inward from the shell portion <NUM> to the combustor connection element <NUM> when installed within the gas turbine engine <NUM>. As shown, the shell portion <NUM> of the combustor shell <NUM> is arranged to contact or be positioned at a forward end or edge of the first vane <NUM>, and defines, in part, a hot gaspath from the combustor section <NUM> to the turbine section <NUM> of the gas turbine engine <NUM>. The shell portion <NUM>, the strut <NUM>, and the combustor connection element <NUM> are arranged as a ring-strut-ring design/configuration. That is, the shell portion <NUM> is a ring arranged at an outer diameter, the combustor connection element <NUM> is arranged as a ring at an inner diameter, and the strut <NUM> extends between and connects the combustor connection element <NUM> to the shell portion <NUM>.

The strut <NUM> is one of a number of struts that are arranged about/between the ring-shapes of the shell portion <NUM> and the combustor connection element <NUM>. The struts <NUM> can provide flexibility and allow for relative movement or adjustments between the combustor connection element <NUM> and the shell portion <NUM>. Such relative movement may occur during operation of the gas turbine engine <NUM>, e.g., at the connection structure <NUM> and/or between the elements thereof.

Turning now to <FIG>, schematic illustrations of a combustor mounting structure <NUM> in accordance with an embodiment of the present disclosure are shown. The combustor mounting structure <NUM> may form part of a combustor section of a gas turbine engine, and includes a shell portion <NUM> attached to a combustor connection element <NUM> by a number of struts <NUM>. The shell portion <NUM> may define a portion of a combustor shell and support one or more combustor panels to define a portion of a combustor of a gas turbine engine. As shown, the shell portion <NUM> is a ring or hoop structure and may be arranged circumferentially about an engine central longitudinal axis Ax. Similarly, the combustor connection element <NUM> is a ring or hoop structure that is arranged circumferentially about the engine central longitudinal axis Ax. The shell portion <NUM> is arranged at an outer radius Ro and the combustor connection element <NUM> is arranged at an inner radius Ri relative to a center point define by the respective rings/hoops (and aligned with the engine central longitudinal axis Ax when installed within a gas turbine engine).

As noted, the shell portion <NUM> is attached to the combustor connection element <NUM> by the struts <NUM>. The struts <NUM> are structural elements that flexibly connect the shell portion <NUM> to the combustor connection element <NUM> to enable mounting of the combustor mounting structure <NUM> to a gas turbine engine, such as to an on-board injector and diffuser case (and proximate a first vane of a turbine section). The combustor connection element <NUM> includes one or more mounting apertures <NUM> for permitting installation of the combustor mounting structure <NUM> within a gas turbine engine using one or more fasteners. Further, the combustor mounting structure <NUM> defines one or more flow apertures <NUM> arranged circumferentially between adjacent struts <NUM>. The flow apertures <NUM> allow for airflow through the combustor mounting structure <NUM>, such as to enter and flow through an on-board injector located proximate the combustor mounting structure <NUM> when installed within a gas turbine engine.

The ring-strut-ring design of the combustor mounting structures described herein can be made to reduce thermal stress contributions and improve part life by reducing strut stiffness using a geometric strut design (e.g., a "wind-back" geometry that incorporates a bend, twist, omega-shape, convolution, etc. geometries). Such geometric designs can reduce radial and axial stiffness and minimize the ring-strut-ring thermal stress by allowing thermal flexibility. Various geometries may be employed for the strut design without departing from the scope of the present disclosure. The strut, and the geometry thereof, may be selected to provide flexibility and the ability of relative movement between components when installed within a gas turbine engine.

Turning now to <FIG>, schematic illustrations of different geometric profiles of combustor mounting structures are shown. In each illustration, the respective combustor mounting structure includes a shell portion that is part of a combustor shell, a combustor connection element arranged radially inward from the shell portion, and a strut extending between and connecting the shell portion and the combustor connection element, as described above. The struts of the example, in some non-limiting embodiments, include geometric portions or geometries that provide and enable flexibility to be provided by the combustor mounting structures.

<FIG> illustrates a combustor mounting structure <NUM> outside the wording of the claims. The combustor mounting structure <NUM> includes a shell portion <NUM> that defines part of a combustor shell <NUM>. The shell portion <NUM> is a ring, hoop, or full circumferential structure that can be installed in a gas turbine engine to define an outlet or downstream end of a combustor of a combustor section of the gas turbine engine. Extending radially inward from the shell portion <NUM>, in a radial direction R, is a strut <NUM> (or plurality of struts) which connects the shell portion <NUM> to a combustor connection element <NUM>. The combustor connection element <NUM> is a ring, hoop, or full circumferential structure that enables engagement and attachment to one or more components of a gas turbine engine during installation (e.g., diffuser case and/or on-board injector, as shown and described above). The strut <NUM> has a radial extent defining an angled portion that causes the combustor connection element <NUM> to be located axial forward of the location of the shell portion <NUM>, in an axial direction A.

<FIG> illustrates a combustor mounting structure <NUM> outside the wording of the claims. The combustor mounting structure <NUM> includes a shell portion <NUM> that defines part of a combustor shell <NUM>. The shell portion <NUM> is a ring, hoop, or full circumferential structure that can be installed in a gas turbine engine to define an outlet or downstream end of a combustor of a combustor section of the gas turbine engine. Extending radially inward from the shell portion <NUM>, in a radial direction R, is a strut <NUM> (or plurality of struts) which connects the shell portion <NUM> to a combustor connection element <NUM>. The combustor connection element <NUM> is a ring, hoop, or full circumferential structure that enables engagement and attachment to one or more components of a gas turbine engine during installation (e.g., diffuser case and/or on-board injector, as shown and described above). The strut <NUM> has a radial extent defining an angled portion that causes the combustor connection element <NUM> to be located axial forward of the location of the shell portion <NUM>, in an axial direction A. The configuration of <FIG> includes additional curvature in the geometric profile of the strut <NUM> as compared to the configuration shown in <FIG>. Further, in this configuration, the strut <NUM> has a variable thickness, with a thicker portion proximate the shell portion <NUM> and a thinner portion proximate the combustor connection element <NUM>. Although shown with a specific change in thickness (axial thickness) in <FIG>, various other changes in thickness of the strut may be employed without departing from the scope of the present disclosure.

<FIG> illustrates a combustor mounting structure <NUM> outside the wording of the claims. The combustor mounting structure <NUM> includes a shell portion <NUM> that defines part of a combustor shell <NUM>. The shell portion <NUM> is a ring, hoop, or full circumferential structure that can be installed in a gas turbine engine to define an outlet or downstream end of a combustor of a combustor section of the gas turbine engine. Extending radially inward from the shell portion <NUM>, in a radial direction R, is a strut <NUM> (or plurality of struts) which connects the shell portion <NUM> to a combustor connection element <NUM>. The combustor connection element <NUM> is a ring, hoop, or full circumferential structure that enables engagement and attachment to one or more components of a gas turbine engine during installation (e.g., diffuser case and/or on-board injector, as shown and described above). The strut <NUM> is arranged to cause the combustor connection element <NUM> to be located axial forward of the location of the shell portion <NUM>, in an axial direction A. In the configuration of <FIG>, the strut <NUM> includes a convolution proximate the shell portion <NUM> and then extends substantially parallel to an axial direction (and forward) to the combustor connection element <NUM>.

<FIG> illustrates a combustor mounting structure <NUM> outside the wording of the claims. The combustor mounting structure <NUM> includes a shell portion <NUM> that defines part of a combustor shell <NUM>. The shell portion <NUM> is a ring, hoop, or full circumferential structure that can be installed in a gas turbine engine to define an outlet or downstream end of a combustor of a combustor section of the gas turbine engine. Extending radially inward from the shell portion <NUM>, in a radial direction R, is a strut <NUM> (or plurality of struts) which connects the shell portion <NUM> to a combustor connection element <NUM>. The combustor connection element <NUM> is a ring, hoop, or full circumferential structure that enables engagement and attachment to one or more components of a gas turbine engine during installation (e.g., diffuser case and/or on-board injector, as shown and described above). The strut <NUM> is arranged to cause the combustor connection element <NUM> to be located axial forward of the location of the shell portion <NUM>, in an axial direction A. In the configuration of <FIG>, the strut <NUM> includes a convolution proximate the combustor connection element <NUM> and a turn proximate the shell portion <NUM>, extending substantially parallel to an axial direction (and forward) from the turn proximate the shell portion <NUM> to the convolution proximate the combustor connection element <NUM>.

<FIG> illustrates a combustor mounting structure <NUM>. The combustor mounting structure <NUM> includes a shell portion <NUM> that defines part of a combustor shell <NUM>. The shell portion <NUM> is a ring, hoop, or full circumferential structure that can be installed in a gas turbine engine to define an outlet or downstream end of a combustor of a combustor section of the gas turbine engine. Extending radially inward from the shell portion <NUM>, in a radial direction R, is a strut <NUM> (or plurality of struts) which connects the shell portion <NUM> to a combustor connection element <NUM>. The combustor connection element <NUM> is a ring, hoop, or full circumferential structure that enables engagement and attachment to one or more components of a gas turbine engine during installation (e.g., diffuser case and/or on-board injector, as shown and described above). The strut <NUM> has a radial extent defining an angled portion that causes the combustor connection element <NUM> to be located axial forward of the location of the shell portion <NUM>, in an axial direction A. In this configuration, the strut <NUM> includes a convolution proximate the shell portion <NUM> and then extends in a radially outward direction (and forward in the axial direction) to the combustor connection element <NUM>.

<FIG> illustrates a combustor mounting structure <NUM>. The combustor mounting structure <NUM> includes a shell portion <NUM> that defines part of a combustor shell <NUM>. The shell portion <NUM> is a ring, hoop, or full circumferential structure that can be installed in a gas turbine engine to define an outlet or downstream end of a combustor of a combustor section of the gas turbine engine. Extending radially inward from the shell portion <NUM>, in a radial direction R, is a strut <NUM> (or plurality of struts) which connects the shell portion <NUM> to a combustor connection element <NUM>. The combustor connection element <NUM> is a ring, hoop, or full circumferential structure that enables engagement and attachment to one or more components of a gas turbine engine during installation (e.g., diffuser case and/or on-board injector, as shown and described above). The strut <NUM> has a radial extent defining a dual-convolution geometry that causes the combustor connection element <NUM> to be located axial forward of the location of the shell portion <NUM>, in an axial direction A. In this configuration, a first convolution is located proximate the shell portion <NUM> and a second convolution is located proximate the combustor connection element <NUM>.

<FIG> illustrates a combustor mounting structure <NUM> outside the wording of the claims. The combustor mounting structure <NUM> includes a shell portion <NUM> that defines part of a combustor shell <NUM>. The shell portion <NUM> is a ring, hoop, or full circumferential structure that can be installed in a gas turbine engine to define an outlet or downstream end of a combustor of a combustor section of the gas turbine engine. Extending radially inward from the shell portion <NUM>, in a radial direction R, is a strut <NUM> (or plurality of struts) which connects the shell portion <NUM> to a combustor connection element <NUM>. The combustor connection element <NUM> is a ring, hoop, or full circumferential structure that enables engagement and attachment to one or more components of a gas turbine engine during installation (e.g., diffuser case and/or on-board injector, as shown and described above). The strut <NUM> has a radial extent defining an omega geometry that causes the combustor connection element <NUM> to be located in axial alignment with the location of the shell portion <NUM>, in an axial direction A.

<FIG> illustrates a combustor mounting structure <NUM> outside the wording of the claims. The combustor mounting structure <NUM> includes a shell portion <NUM> that defines part of a combustor shell <NUM>. The shell portion <NUM> is a ring, hoop, or full circumferential structure that can be installed in a gas turbine engine to define an outlet or downstream end of a combustor of a combustor section of the gas turbine engine. Extending radially inward from the shell portion <NUM>, in a radial direction R, is a strut <NUM> (or plurality of struts) which connects the shell portion <NUM> to a combustor connection element <NUM>. The combustor connection element <NUM> is a ring, hoop, or full circumferential structure that enables engagement and attachment to one or more components of a gas turbine engine during installation (e.g., diffuser case and/or on-board injector, as shown and described above). The strut <NUM> has a radial extent defining an aft-direction slope or angle geometry that causes the combustor connection element <NUM> to be located in axial position aft of the location of the shell portion <NUM>, in an axial direction A.

The various configurations of <FIG> provide for example geometries and configurations for the strut of the disclosed combustor mounting structures. The particular geometry employed in a given application or engine configuration may be selected based on various considerations. For example, without limitation, thermal stress contributions, flow blockage to combustor dilution holes, other hardware obstructions (e.g., design of on-board injector), and ease of manufacturing (e.g., machining process or welded construction) may all play role in a selected geometry and/or design of a combustor mounting structure. In accordance with various configurations, embodiments described herein can provide minimal impact to flow through combustor dilution holes, allow for geometric clearance with respect to on-board injector hardware, improve manufacturing ease and/or efficiencies, provide for reduced stiffness to minimize thermal stresses, and can eliminate the need for a conformal seal between the combustor inner aft surface and a first vane of a turbine section. In some embodiments, additional features, such as transition thickness of the strut (from the shell portion to the combustor connection element) can be varied to minimize the stress concentration factor from defined transition radii.

Advantageously, embodiments described herein allow improved mounting and operation of gas turbine engines, particularly at a junction between a combustor section and a turbine sanction thereof. For example, advantageously, embodiments described herein can divorce the conformal seal wear from the combustor bolts, support or eliminate the need for inner conformal seal, and provide for improved durability life (e.g., low cycle fatigue and crack growth lives). Further, advantageously, the strut design of embodiments of the present disclosure does not block the combustor dilution holes or interfere with on-board injector hardware. Furthermore, advantageously, various geometries and/or embodiments shown and described herein may minimize the local peak stress concentration by use of a strut having a gradual thickness transition between the outer (shell portion) and inner (combustor connection element) rings.

As used herein, the term "about" is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, "about" may include a range of ± <NUM>%, or <NUM>%, or <NUM>% of a given value or other percentage change as will be appreciated by those of skill in the art for the particular measurement and/or dimensions referred to herein.

Claim 1:
A combustor mounting structure (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) for a gas turbine engine (<NUM>), the combustor mounting structure comprising:
a shell portion (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) defining an outer ring arranged at an outer radius relative to a central axis;
a combustor connection element (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) defining an inner ring arranged at an inner radius that is less than the outer radius relative to the central axis; and
a plurality of struts (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) extending radially between and connecting the shell portion (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) to the combustor connection element (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>), wherein one or more flow apertures (<NUM>) are defined between the shell portion and the combustor connection element in a radial direction and between adjacent struts of the plurality of struts in a circumferential direction;
characterised in that:
each strut of the plurality of struts (<NUM>; <NUM>) extends radially inward from the shell portion (<NUM>; <NUM>) and includes at least one convolution proximate the shell portion and then extends in the radially outward direction and in the axially forward direction and then to the combustor connection element.