Patent Description:
Gas turbine engine combustors are subject to high thermal loads for prolonged periods of time. To alleviate the accompanying thermal stresses, the walls of the combustors are typically cooled to extend the usable service life of the combustor components and therefore improve reliability of the gas turbine engine.

An annular combustor typically includes an outer combustor shell and a set of inner combustor panels secured to the combustor shell to thermally protect the combustor shell from hot combustion gases. The combustor panels are typically secured to the combustor shell by a plurality of mechanical fastener arrangements. The mechanical fastener arrangement often includes a stud that extends from the combustor panel through a stud opening in the combustor shell, and is secured at the combustor shell via a nut or similar component. Such arrangements subject the studs to high temperatures, reducing the service life of the combustor panels. <CIT>, which is prior art in the sense of Article <NUM>(<NUM>) EPC, discloses a combustor for a gas turbine engine, comprising: a combustor shell having a shell opening therethrough; a combustor panel having a stud attached thereto, the stud extending through the shell opening, the stud including a standoff to define an intermediate passage between the combustor shell and the combustor panel; a retainer attached to the stud; and a washer surrounding the stud and positioned between the retainer and the combustor shell, the washer defining a cooling flow passage configured to direct a cooling airflow through the shell opening to impinge the cooling flow on the stud and on the standoff. The washer according to the above-mentioned document comprises: a first washer surface; a second washer surface opposite the first washer surface; an outer perimeter surface extending between the first washer surface and the second washer surface; and a cooling flow passage to direct a cooling airflow therethrough.

<CIT> discloses a washer for a stud in a combustion chamber, the washer comprising a cooling channel to supply coolant to the stud.

<CIT> discloses a combustion chamber arrangement comprising a plurality of tiles secured to an outer annular wall by at least one stud and a cooperating nut. An associated washer comprises one or more passages extending therethrough from the rim to the bore of the washer to supply coolant to the stud.

<CIT> discloses a combustor lining comprising holes for cooling elements of the combustor section,.

<CIT> discloses a washer comprising a plurality of lobes and being for a mid turbine frame assembly.

<CIT> discloses a washer for a turbine engine combustor comprising a cooling passage.

<CIT> discloses a washer for a mounting stud for securing a heat shield in a combustor.

<CIT> discloses a bearer plate for use with rock bolts or friction rock stabilisers.

According to a first aspect, the invention provides a combustor for a gas turbine engine comprising a combustor shell having a shell opening therethrough, a combustor panel having a stud attached thereto, the stud extending through the shell opening. The stud includes a standoff to define an intermediate passage between the combustor shell and the combustor panel. A retainer is attached to the stud. A washer surrounds the stud and is positioned between the retainer and the combustor shell. The washer at least partially defines a cooling flow passage configured to direct a cooling airflow through the shell opening to impinge the cooling flow on at least one of the stud or the standoff.

The washer may include a groove to define the cooling flow passage between the washer and the combustor shell and/or between the washer and the retainer.

The washer may be wave-shaped around an outer perimeter of the washer.

The cooling flow passage extends from a passage inlet located at an outer perimeter of the washer to a passage outlet located at an inner perimeter of the washer.

The cooling flow passage tapers from the passage inlet to the passage outlet.

In an embodiment not falling under the scope of protection of the claims, the washer may include a plurality of washer arms extending radially inwardly from an outer perimeter of the washer, the cooling flow passage defined between adjacent washer arms of the plurality of washer arms.

Each washer arm may include a web portion and a relatively circumferentially wide end portion located radially inboard of the web portion.

Adjacent washer arms may not contact each other.

The washer may include a washer sleeve extending through the shell opening, the cooling flow passage at least partially defined by the washer sleeve.

The cooling flow passage may include a passage inlet located at an outer perimeter of the washer, and a passage outlet located at an axial end of the washer sleeve.

The washer may include a plurality of ribs to define the passage inlet between the washer and the combustor shell.

According to a second aspect, the present invention provides a washer for a combustor of a gas turbine engine includes a first washer surface, a second washer surface opposite the first washer surface, an outer perimeter surface extending between the first washer surface and the second washer surface, and a cooling flow passage to direct a cooling airflow therethrough.

A groove may be located at one of the first washer surface or the second washer surface to at least partially define the cooling flow passage.

The cooling flow passage extends from a passage inlet located at the outer perimeter surface to a passage outlet located at an inner perimeter of the washer, wherein the cooling flow passage tapers from the passage inlet to the passage outlet.

In an embodiment not falling under the scope of protection of the claims, a plurality of washer arms may extend radially inwardly from the outer perimeter surface of the washer, the cooling flow passage may be defined between adjacent washer arms of the plurality of washer arms.

A washer sleeve may extend from the first surface, the cooling flow passage may at least be partially defined by the washer sleeve.

According to a third aspect, the invention provides a gas turbine engine includes a turbine section, and a combustor according to the first aspect above The following descriptions should not be considered limiting in any way.

A detailed description of one or more embodiments of the invention are presented herein by way of exemplification with reference to the Figures.

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 epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about <NUM>:<NUM>.

The fan section <NUM> of the engine <NUM> is designed for a particular flight condition--typically cruise at about <NUM> Mach and about <NUM>,<NUM> feet (<NUM>,<NUM> meters).

Referring to <FIG>, the combustor <NUM> includes a combustor shell <NUM> having an inboard side <NUM> and an outboard side <NUM>. A plurality of combustor liner panels <NUM> are located at the inboard side <NUM> and are secured to the combustor shell <NUM> and define a combustion chamber <NUM>. The combustor <NUM> includes one or more fuel nozzles (not shown), which in some embodiments extend into the combustion chamber <NUM>. The combustor liner panels <NUM> are formed and configured to shield or protect the combustor shell <NUM>, in particular the inboard side <NUM> from heat generated in the combustor chamber <NUM> by combustion of fuel from the fuel nozzle. During operation of the combustor <NUM>, compressed cooling air is circulated at the outboard side <NUM> of the combustor shell <NUM> to provide cooling thereto. A portion of the cooling air, shown schematically at <NUM>, passes through shell cooling openings <NUM> in the combustor shell <NUM> and into intermediate passage <NUM> between the combustor shell <NUM> and the combustor liner panels <NUM>. Further, a portion of the cooling air <NUM> may pass through one or more panel openings <NUM> in the combustor liner panels <NUM> to cool an inboard liner surface <NUM> by, for example, film cooling.

Now referring to <FIG>, an attachment of a combustor liner panel <NUM> to the combustor shell <NUM> is illustrated. The combustor liner panel <NUM> includes at least one stud <NUM> extending from a back surface <NUM> of the combustor liner panel <NUM> across the intermediate passage <NUM> and through a shell stud opening <NUM> (shown in <FIG>) in the combustor shell <NUM>. The stud <NUM> includes a stud head <NUM> located at the combustor liner panel <NUM> with a stud shaft <NUM> extending therefrom. In some embodiments, the stud shaft <NUM> is threaded. A washer <NUM> is located over the stud shaft <NUM> and a nut <NUM> is installed to the stud shaft <NUM> to retain the combustor liner panel <NUM> to the combustor shell <NUM>. To maintain spacing between the combustor shell <NUM> and the combustor liner panel <NUM> and define the intermediate passage <NUM>, standoffs <NUM> (best shown in <FIG>) are arranged around the stud shaft <NUM> and extend from the stud head <NUM> toward the combustor shell <NUM>.

As shown in <FIG>, the washer <NUM>, the stud <NUM> and the shell stud opening <NUM> define stud cooling passages <NUM> to allow cooling air <NUM> to pass therethrough and impinge on the stud shaft <NUM> and the standoffs <NUM> to reduce the temperatures of the stud shaft <NUM> and the standoffs <NUM>, thereby extending their useful life. Referring to <FIG>, the washer <NUM> has a first washer side <NUM> and a second washer side <NUM> opposite the first washer side <NUM> and is annular in shape, having an inner perimeter <NUM> defining a washer opening <NUM> and an outer perimeter <NUM>. In the embodiment of <FIG>, the washer <NUM> includes washer grooves <NUM> formed in the first washer side <NUM> and/or the second washer side <NUM>, extending radially inwardly from the outer perimeter <NUM> to the inner perimeter <NUM>. In some embodiments, the inner perimeter <NUM> and the outer perimeter <NUM> are circular. When the washer <NUM> and the nut <NUM> are installed to the stud <NUM>, the washer grooves <NUM> define cooling passages <NUM> between the washer <NUM> and the combustor shell <NUM> as shown in <FIG>, and cooling passages <NUM> between the washer <NUM> and the nut <NUM> as shown in <FIG>. The cooling flow <NUM> flows through the cooling passages <NUM> and between the stud shaft <NUM> and the shell stud opening <NUM> to impinge on the stud <NUM> and the standoffs <NUM>.

Referring now to <FIG> and <FIG>, the washer <NUM> may be formed as a "wavy washer" with the first washer side <NUM> and the second washer side <NUM> each having a wave shape, while maintaining a substantially constant washer thickness <NUM>. When the washer <NUM> and the nut <NUM> are installed to the stud <NUM>, cooling passages <NUM> are defined between the first washer side <NUM> and the combustor shell <NUM> and between the second washer side <NUM> and the nut <NUM> in an alternating pattern around the outer perimeter <NUM>. The cooling flow <NUM> flows through the cooling passages <NUM> and between the stud shaft <NUM> and the shell stud opening <NUM> (both shown in <FIG>) to impinge on the stud <NUM> and the standoffs <NUM>.

Referring now to <FIG> and <FIG>, in some embodiments the washer <NUM> includes a plurality of dimples formed therein, exhibited as a plurality of protrusions <NUM> in the first washer side <NUM> and corresponding recesses <NUM> at the second washer side <NUM>. When the washer <NUM> and the nut <NUM> are installed to the stud <NUM>, the protrusions <NUM> define the cooling passages <NUM> between the first washer side <NUM> and the combustor shell <NUM> around the outer perimeter <NUM>. The cooling flow <NUM> flows through the cooling passages <NUM> and between the stud shaft <NUM> and the shell stud opening <NUM> (both shown in <FIG>) to impinge on the stud <NUM> and the standoffs <NUM>.

Referring now to <FIG> and <FIG>, in some embodiments the washer includes a plurality of through passages <NUM> extending from the outer perimeter <NUM> to the inner perimeter <NUM>. Each through passage has a passage inlet <NUM> located at the outer perimeter <NUM>, and a passage outlet <NUM> located at the inner perimeter <NUM>. A cross-sectional size of the through passage <NUM> decreases with distance from the passage inlet <NUM>. Further, in some embodiments the through passage <NUM> extends along a passage central axis <NUM> non-perpendicular to the stud shaft <NUM>. In some embodiments, the passage inlet <NUM> and/or the passage outlet <NUM> are circular in cross-section, but it is to be appreciated that other cross-sectional shapes such as oval or elliptical may be utilized. The cooling flow <NUM> flows through the through passages <NUM> and between the stud shaft <NUM> and the shell stud opening <NUM> to impinge on the stud <NUM> and the standoffs <NUM>.

Referring now to <FIG> and <FIG>, the washer <NUM> includes a continuous outer perimeter <NUM> and a plurality of washer arms <NUM> extending radially inwardly from the outer perimeter <NUM>. Airflow passages <NUM> are defined between adjacent washer arms <NUM> and the washer arms <NUM> further define the inner perimeter <NUM> of the washer <NUM>. In some embodiments, adjacent washer arms <NUM> do not contact each other. The airflow passages <NUM> extend through the washer <NUM> from the first washer side <NUM> to the second washer side <NUM> and allow the cooling flow <NUM> to flow through the airflow passages <NUM> and then between the stud shaft <NUM> and the shell stud opening <NUM> to impinge on the stud <NUM> and the standoffs <NUM>.

Referring to <FIG>, in some embodiments, the washer arms <NUM> include a web portion <NUM> and a relatively circumferentially wide end portion <NUM> located radially inboard of the web portion <NUM>. In some embodiments, the end portion <NUM> is substantially rectangular in an axial cross-section. It is to be appreciated, however, that the end portion <NUM> may be shapes other than rectangular such as a curvilinear shape as shown in <FIG>, depending on cooling flow <NUM> requirements and other factors. Further, in other embodiments, the washer arms <NUM> may be a constant width along their radial extent. In the embodiments of <FIG>, six washer arms <NUM> are illustrated, while it is to be appreciated that other quantities of washer arms <NUM>, such as <NUM>, <NUM> or <NUM> washer arms <NUM>, may be utilized in other embodiments.

Referring now to <FIG>, in some embodiments, the washer <NUM> includes a sleeve <NUM>, in some embodiments formed integrally with the washer <NUM>. The sleeve <NUM> extends in an axial direction and in some embodiments through the shell stud opening <NUM> and in some embodiments extends at least partially into the intermediate passage <NUM> as shown. The sleeve <NUM> includes one or more sleeve passages <NUM> extending from a passage inlet <NUM> at the outer perimeter <NUM> of the washer <NUM>, to a passage outlet <NUM> at a sleeve end <NUM> of the sleeve <NUM>. The sleeve passages <NUM> allow the cooling flow <NUM> to flow through the shell stud opening <NUM> and out of the passage outlets <NUM> to impinge on the stud <NUM> and the standoffs <NUM>.

As shown in <FIG>, the passage inlets <NUM> are defined between adjacent washer ribs <NUM> that define the outer perimeter <NUM> of the washer <NUM>. In some embodiments, the washer <NUM> includes <NUM> washer ribs <NUM> and thus <NUM> passage inlets <NUM>, while in other embodiments other quantities of washer ribs <NUM> and thus other quantities of passage inlets <NUM> may be utilized. Referring now to <FIG>, the passage outlets <NUM> in the sleeve end <NUM> of the sleeve <NUM> may have an oval, elliptical, rectangular or other polygonal and/or curvilinear shape. In the embodiment illustrated, <NUM> passage outlets <NUM> are shown, but one skilled in the art will readily appreciate that other quantities of passage outlets <NUM>, such as <NUM>, <NUM>, <NUM>, or <NUM> or more passage outlets <NUM> may be utilized.

In another embodiment illustrated in <FIG>, the washer ribs <NUM> are located at the first washer side <NUM> and define the passage inlets <NUM> between the first washer side <NUM> and the combustor shell <NUM>, and the sleeve passages <NUM> are similarly defined between a sleeve outer surface <NUM> and the combustor shell <NUM> and extend to passage outlets <NUM>. In this embodiment, the sleeve passages <NUM> allow the cooling flow <NUM> to flow through the shell stud opening <NUM> and out of the passage outlets <NUM> to impinge on the stud <NUM> and the standoffs <NUM>.

While the present invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present invention.

Claim 1:
A combustor (<NUM>) for a gas turbine engine (<NUM>), comprising:
a combustor shell (<NUM>) having a shell opening (<NUM>) therethrough;
a combustor panel (<NUM>) having a stud (<NUM>) attached thereto, the stud extending through the shell opening, the stud including a standoff (<NUM>) to define an intermediate passage (<NUM>) between the combustor shell and the combustor panel;
a retainer (<NUM>) attached to the stud; and
a washer (<NUM>) surrounding the stud and positioned between the retainer and the combustor shell, the washer at least partially defining a cooling flow passage (<NUM>) configured to direct a cooling airflow (<NUM>) through the shell opening to impinge the cooling flow on at least one of the stud or the standoff,
wherein the cooling flow passage extends from a passage inlet (<NUM>) located at an outer perimeter (<NUM>) of the washer to a passage outlet (<NUM>) located at an inner perimeter (<NUM>) of the washer, and wherein the cooling flow passage tapers from the passage inlet to the passage outlet.