Film-cooled multi-walled structure with one or more indentations

An assembly for a turbine engine is provided. This turbine engine assembly includes a shell and a heat shield with a cooling cavity between the shell and the heat shield. The heat shield defines a plurality of cooling apertures and an indentation in a side of the heat shield opposite the cooling cavity. The cooling apertures are fluidly coupled with the cooling cavity. The indentation is configured such that cooling air, directed from a first of the cooling apertures, at least partially circulates against the side of the heat shield.

BACKGROUND OF THE INVENTION

1. Technical Field

This disclosure relates generally to a film cooled multi-walled structure of a turbine engine.

2. Background Information

A floating wall combustor for a turbine engine typically includes a bulkhead that extends radially between inner and outer combustor walls. Each of the combustor walls includes a shell and a heat shield, where the heat shields define opposed radial sides of a combustion chamber. Cooling cavities are defined radially between the heat shield and the shell. These cooling cavities fluidly couple impingement apertures defined in the shell with effusion apertures defined in the heat shield.

During turbine engine operation, the impingement apertures direct cooling air into the cooling cavities to impinge against the heat shield. The effusion apertures subsequently direct the cooling air into the combustion chamber to film cool the heat shield. The cooling air flowing out of each effusion aperture, for example, may form a film that generally flows against a downstream portion of the heat shield to provide film cooling. However, turbulent core air within the combustion chamber may cause the film to detach from the heat shield after only traveling a relatively small distance and mix with the core air. As a result, some portions of the heat shield may receive limited film cooling.

There is a need in the art for an improved film cooled multi-walled structure such as a turbine engine combustor wall.

SUMMARY OF THE DISCLOSURE

According to an aspect of the invention, an assembly is provided for a turbine engine. This turbine engine assembly includes a shell and a heat shield with a cooling cavity between the shell and the heat shield. The heat shield defines a plurality of cooling apertures and an indentation in a side of the heat shield opposite the cooling cavity. The cooling apertures are fluidly coupled with the cooling cavity. The indentation is configured such that cooling air, directed from a first of the cooling apertures, at least partially circulates against the side of the heat shield.

According to another aspect of the invention, another assembly is provided for a turbine engine. This turbine engine assembly includes a shell and a heat shield attached to the shell with a cooling cavity extending between the heat shield and the shell. The heat shield defines a plurality of cooling apertures and an indentation in a side of the heat shield opposite the cooling cavity. The cooling apertures are fluidly coupled with the cooling cavity. An outlet of a first of the cooling apertures is located at an edge of the indentation.

The indentation may be configured such that cooling air, directed from the outlet, at least partially circulates against the side of the heat shield; e.g., within the indentation.

The shell may define a plurality of cooling apertures that are fluidly coupled with the cooling apertures in the heat shield by the cooling cavity.

The heat shield includes a first surface and a second surface with the first surface defining an outlet of the first of the cooling apertures and the second surface defining the indentation. The first and the second surface may be adjacent and contiguous with one another. Alternatively, the first surface may be separated from the second surface by a distance. The outlet of the first of the cooling apertures may also or alternatively intersect with the indentation.

An outlet of the first of the cooling apertures may be separated from the indentation by a distance.

The first of the cooling apertures may be circumferentially or otherwise (e.g., axially) aligned with the indentation. Alternatively, the first of the cooling apertures may be circumferentially or otherwise (e.g., axially) offset from the indentation.

A surface that defines the indentation may have a circular peripheral geometry. Alternatively, the surface may have an oval peripheral geometry. Alternatively, the surface may have a peripheral geometry with one or more concave sections and one or more convex sections; e.g., a pear-shaped peripheral geometry. Still alternatively, an annular surface of the heat shield may define the indentation.

A second of the cooling apertures may be configured to direct cooling air away from the cooling cavity. The indentation may be configured such that cooling air, directed from the second cooling aperture, at least partially circulates against the side of the heat shield; e.g., within the indentation.

The heat shield may define a second indentation in the side of the heat shield. This second indentation may be configured such that cooling air, directed from a second of the cooling apertures, at least partially circulates against the side of the heat shield; e.g., within the second indentation.

The heat shield may include an arcuate panel in which the first of the cooling apertures and the indentation are defined.

The turbine engine assembly may include a tubular combustor wall that includes the shell and the heat shield.

The heat shield may extend vertically between a chamber surface and a cavity surface that defines a portion of the cooling cavity. A point (e.g., a low point) of an indentation surface, which defines the indentation, may be located a vertical distance from the cavity surface. The vertical distance may be between about fifty percent (50%) and about ninety percent (90%) of a vertical thickness of the heat shield measured between the cavity and the chamber surfaces.

A cross-sectional area of the outlet may be between about one percent and about fifty percent of an area of an indentation surface, where the indentation surface defines the indentation.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a side cutaway illustration of a geared turbine engine20. This turbine engine20extends along an axial centerline22between an upstream airflow inlet24and a downstream airflow exhaust26. The turbine engine20includes a fan section28, a compressor section29, a combustor section30and a turbine section31. The compressor section29includes a low pressure compressor (LPC) section29A and a high pressure compressor (HPC) section29B. The turbine section31includes a high pressure turbine (HPT) section31A and a low pressure turbine (LPT) section31B. The engine sections28-31are arranged sequentially along the centerline22within an engine housing34, which includes a first engine case36and a second engine case38.

Each of the engine sections28,29A,29B,31A and31B includes a respective rotor40-44. Each of the rotors40-44includes a plurality of rotor blades arranged circumferentially around and connected to (e.g., formed integral with or mechanically fastened, welded, brazed, adhered or otherwise attached to) one or more respective rotor disks. The fan rotor40is connected to a gear train46(e.g., an epicyclic gear train) through a fan shaft47. The gear train46and the LPC rotor41are connected to and driven by the LPT rotor44through a low speed shaft48. The HPC rotor42is connected to and driven by the HPT rotor43through a high speed shaft50. The shafts47,48and50are rotatably supported by a plurality of bearings52; e.g., rolling element bearings. Each of the bearings52is connected to the second engine case38by at least one stationary structure such as, for example, an annular support strut.

Air enters the turbine engine20through the airflow inlet24, and is directed through the fan section28and into an annular core gas path54and an annular bypass gas path56. The air within the core gas path54may be referred to as “core air”. The air within the bypass gas path56may be referred to as “bypass air”.

The core air is directed through the engine sections29-31and exits the turbine engine20through the airflow exhaust26. Within the combustor section30, fuel is injected into a combustion chamber58and mixed with the core air. This fuel-core air mixture is ignited to power the turbine engine20and provide forward engine thrust. The bypass air is directed through the bypass gas path56and out of the turbine engine20through a bypass nozzle68to provide additional forward engine thrust. Alternatively, the bypass air may be directed out of the turbine engine20through a thrust reverser to provide reverse engine thrust.

FIG. 2illustrates an assembly62of the turbine engine20. This turbine engine assembly62includes a combustor64. The turbine engine assembly62also includes one or more fuel injector assemblies66, each of which may include a fuel injector68mated with a swirler70.

The combustor64may be configured as an annular floating wall combustor, which may be arranged within an annular plenum72of the combustor section30. The combustor64ofFIGS. 2 and 3, for example, includes an annular combustor bulkhead74, a tubular combustor inner wall76, and a tubular combustor outer wall78. The bulkhead74extends radially between and is connected to the inner wall76and the outer wall78. The inner wall76and the outer wall78each extends axially along the centerline22from the bulkhead74towards the turbine section31A, thereby defining the combustion chamber58.

Referring toFIG. 2, the inner wall76and the outer wall78may each have a multi-walled structure; e.g., a dual-walled hollow structure. The inner wall76and the outer wall78ofFIG. 2, for example, each includes a tubular combustor shell80and a tubular combustor heat shield82. The inner wall76and the outer wall78also each includes one or more cooling cavities84(e.g., impingement cavities) and one or more quench apertures86, which are arranged circumferentially around the centerline22(seeFIG. 3).

The shell80extends circumferentially around the centerline22. The shell80extends axially along the centerline22between an upstream end88and a downstream end90. The shell80is connected to the bulkhead74at the upstream end88. The shell80may be connected to a stator vane assembly92or the HPT section31A at the downstream end90.

Referring toFIG. 4, the shell80includes a plenum surface94, a cavity surface96and one or more aperture surfaces98. The shell80extends radially between the plenum surface94and the cavity surface96. The plenum surface94defines a portion of the plenum72(see alsoFIG. 2). The cavity surface96defines a portion of one or more of the cavities84.

Each of the aperture surfaces98defines a cooling aperture100. The cooling aperture100extends (e.g., radially) through the shell80from the plenum surface94to the cavity surface96. Each cooling aperture100may be configured as an impingement aperture. Each aperture surface98ofFIG. 4, for example, is configured to direct a jet of cooling air to impinge substantially perpendicularly against the heat shield82as described below in further detail.

Referring toFIG. 2, the heat shield82extends circumferentially around the centerline22. The heat shield82extends axially along the centerline22between an upstream end and a downstream end. The heat shield82may include one or more heat shield panels102, one or more of which may have an arcuate geometry. These panels102may be arranged into one or more panel arrays. The panel arrays are arranged at discrete locations along the centerline22. The panels102in each array are disposed circumferentially around the centerline22and form a hoop. Alternatively, the heat shield82may be configured from one or more tubular bodies.

FIGS. 5 and 6illustrate exemplary portions of one of the walls76,78. It should be noted, referring toFIG. 4, that the heat shield82includes one or more cooling apertures104and one or more indentations106as described below in further detail. For ease of illustration, however, the shell80and the heat shield82ofFIGS. 5 and 6are respectively shown without the cooling apertures100and104and the indentations106.

Each of the panels102includes a panel base108and one or more panel rails (e.g., rails110-113). The panel base108may be configured as a generally curved (e.g., arcuate) plate. The panel base108extends axially between an upstream axial end114and a downstream axial end116. The panel base108extends circumferentially between opposing circumferential ends118and120.

Referring toFIG. 4, the panel base108includes at least one cavity surface122, a chamber surface124, one or more indentation surfaces126, and one or more aperture surfaces128. The panel base108extends radially between the cavity surface122and the chamber surface124. The cavity surface122defines a portion of a side of a respective one of the cooling cavities84. The chamber surface124defines a portion of a side of the combustion chamber58.

Referring toFIGS. 7 and 8, each of the indentation surfaces126is located on a side130(e.g., a hot side) of the heat shield82that faces the combustion chamber58, and is operatively disposed on an opposite side (e.g., a cold side) of the heat shield82opposite surface122, which faces a respective one of the cooling cavities84. The indentation surface126is thus defined opposite the cooling cavity84. Each indentation surface126may be integrally formed with the chamber surface124, but is also radially recessed therefrom along a substantial portion thereof as shown. A low point132of the indentation surface126ofFIG. 7, for example, is located a radial distance134from the cavity surface122. This radial distance134may be, for example, between about fifty percent (50%) and about ninety percent (90%) or more of a radial thickness136of the respective panel102as measured, for example, radially between the cavity and the chamber surfaces122and124proximate the respective indentation surface126. An edge138of the indentation surface126, however, may be contiguous with the chamber surface124. In this manner, each indentation surface126defines a respective one of the indentations106in the side130of the heat shield82.

The indentation surface126ofFIGS. 7 and 8may have a partial-hemispherical shape with a circular peripheral geometry. The indentation surface126, for example, has a substantially constant radius. The present invention, however, is not limited to any particular indentation surface configurations. In the embodiment ofFIG. 9, for example, the indentation surface126has a parti-ellipsoidal shape with a changing radius. In the embodiment ofFIG. 10, a central portion140of the indentation surface126is planar and the radial distance134is substantially constant. In the embodiment ofFIG. 11, the indentation surface126has an elongate (e.g., oval) peripheral geometry. In the embodiment ofFIG. 12, the indentation surface126has another elongated (e.g., teardrop-shaped) peripheral geometry. In the embodiment ofFIG. 13, the indentation surface126has still another elongated (e.g., pear-shaped) peripheral geometry with one or more concave sections142and one or more convex sections144. In addition, while the indentation surfaces126are described and illustrated above as being located at discrete points in the heat shield82, some of the indentation surfaces126(seeFIG. 14) of the panels102in at least one of the arrays may form a collective annular indentation surface146that extend circumferentially around the centerline22and defines an annular indentation148.

Referring again toFIG. 4, each of the aperture surfaces128defines one of the cooling apertures104and its respective outlet150in the chamber surface124. Each cooling aperture104extends diagonally (e.g., radially as well as axially and/or circumferentially) through the panel base108from the cavity surface122to the chamber surface124. Each cooling aperture104may be configured as an effusion aperture. Each aperture surface128ofFIG. 4, for example, is configured to direct a jet of cooling air out of its outlet150such that the cooling air forms a film against a downstream portion of the heat shield82as described below in further detail.

To facilitate the formation of the film against the heat shield82, one or more of the cooling apertures104may each be acutely angled relative to the chamber surface124. A width (e.g., diameter) of one or more of the cooling aperture104may also or alternatively each increase as the aperture104extends from the cavity surface122to the chamber surface124, which provides the respective cooling aperture104with a diverging geometry. With the foregoing configuration, each cooling aperture104may direct cooling air into the combustion chamber58at a relatively slow velocity and along a trajectory that promotes formation of the film against the heat shield82and/or reduces cooling air blow off of the chamber surface124. The smaller inlet of each cooling aperture104may also serve to meter cooling air out of the cooling cavity84. In addition, the diverging geometry increases the surface area of the aperture surface128, which may increase cooling of the heat shield82.

One or more of the aperture surfaces128are each configured such that the respective outlet150is located generally upstream of and at (e.g., on, adjacent or proximate) the edge138of a respective one of the indentation surfaces126. The outlet150ofFIGS. 7 and 8and, more particularly, a downstream portion of the aperture surface128defining the outlet150, for example, is separated from an upstream portion152of the edge138by an axial (and/or circumferential) distance154. In another embodiment, the aperture surface128defining the outlet150ofFIG. 15is adjacent and contiguous with the upstream portion152of the edge138. In another embodiment, the aperture surface128defining the outlet150ofFIG. 16intersects the upstream portion152of the edge138. In still another embodiment, the aperture surface128defining the outlet150ofFIG. 16intersects the indentation surface126proximate (or adjacent) the upstream portion152of the edge138; e.g., the outlet150is within the indentation106.

Referring again toFIG. 8, the aperture surface128may also be configured such that a cross-sectional area of the outlet150is less than an area of the respective adjacent indentation surface126. The cross-sectional area of the outlet150ofFIG. 8, for example, may be between about one percent (1%) and about fifty percent (50%) of the area of the indentation surface126. The outlet150has a first width156(e.g., axial diameter) that may be less than a corresponding width158(e.g., axial diameter) of the indentation surface126, which in turn may be less than a (e.g., axial) distance between adjacent upstream and downstream outlets150surrounding the indentation surface126(seeFIG. 4). The outlet150has a second width160(e.g., a circumferential diameter) that may be less than a corresponding width162(e.g., a circumferential diameter) of the indentation surface126.

The aperture surface128defining the outlet150may be aligned with a respective one of the indentation surfaces126. A centroid164of the outlet150ofFIG. 8, for example, is substantially circumferentially aligned with a centroid166of the indentation surface126and, thus, the indentation106. In other embodiments, however, the centroid164may be circumferentially offset from the centroid166by a distance as illustrated inFIG. 18. In still other embodiments, the centroid164and/or the aperture surface128may be circumferentially offset from the centroid166and/or the entire indentation surface126by a distance as illustrated inFIG. 19. The outlet150, however, may still be located generally upstream of the indentation106. For example, local air flow adjacent the indentation surface126and/or cooling air directed out of the outlet150may move generally circumferentially along a trajectory indicated by arrow168during engine operation.

Referring toFIGS. 5 and 6, the panel rails may include one or more circumferentially extending end rails110and111and one more axially extending end rails112and113. Each of the foregoing rails110-113of the inner wall76extends radially in from the respective panel base108; see alsoFIG. 2. Each of the rails110-113of the outer wall78extends radially out from the respective panel base108; see alsoFIG. 2. The rail110is arranged at the axial end114. The rail111is arranged at the axial end116. The rails112and113extend axially between and are connected to the rails110and111. The rail112is arranged at the circumferential end118. The rail113is arranged at the circumferential end120.

Referring toFIG. 2, the heat shield82of the inner wall76circumscribes the shell80of the inner wall76, and defines an inner side of the combustion chamber58. The heat shield82of the outer wall78is arranged radially within the shell80of the outer wall78, and defines an outer side of the combustion chamber58that is opposite the inner side. The heat shield82and, more particularly, each of the panels102may be respectively attached to the shell80by a plurality of mechanical attachments170(e.g., threaded studs respectively mated with washers and nuts); see alsoFIG. 5. The shell80and the heat shield82thereby respectively form the cooling cavities84in each of the walls76,78.

Referring toFIGS. 5 and 6, each of the cooling cavities84is defined radially by and extends radially between the cavity surface96and a respective one of the cavities surfaces122as set forth above. Each cooling cavity84may be defined circumferentially by and extend circumferentially between the rails112and113of a respective one of the panels102. Each cooling cavity84may be defined axially by and extend axially between the rails110and111of a respective one of the panels102. In this manner, referring toFIG. 4, each cooling cavity84may fluidly couple one or more of the cooling apertures100with one or more of the cooling apertures104.

Still referring toFIG. 4, during turbine engine operation, core air from the plenum72is directed into each of the cooling cavities84through respective cooling apertures100. This core air (e.g., cooling air) may impinge against the panel base108, thereby impingement cooling the heat shield82. The cooling air within each cooling cavity84is subsequently directed through respective cooling apertures104and into the combustion chamber58, thereby film cooling a downstream portion of the heat shield82as described below in further detail. Within each cooling aperture104, the cooling air may also cool the heat shield82through convective heat transfer.

The aperture surface128ofFIGS. 20 and 21may direct the cooling air out of the outlet150to provide a film of cooling air against the chamber surface124and the indentation surface126. Since the indentation surface126is recessed in from the chamber surface124, a fluid suction force may be generated that pulls the cooling air film into the indentation106and/or radially towards the indentation surface126; e.g., pressure within the indentation106may be less than that within an adjacent region172of the combustion chamber58. In this manner, the cooling air film may remain “attached” to the heat shield82(e.g., the indentation surface126and the chamber surface124) for a relatively long distance. In addition, shear force between the cooling air film and the core air flowing through the combustion chamber58may induce vortices within the cooling air film. These vortices may cause some or all of the cooling air film to circulate and/or re-circulate against the side130of the heat shield82; e.g., within the indentation106. Such cooling air circulation may increase the thermal boundary layer between the relatively hot core gas and the heat shield82, thereby further reducing the temperature of the heat shield82.

Referring toFIG. 22, in some embodiments, a plurality of the aperture surfaces128may be configured to direct cooling air towards a common one of the indentation surfaces126; see alsoFIG. 14. The aperture surfaces128ofFIG. 22, for example, are configured such that the respective outlets150are located proximate the edge138of the indentation surface126. In this manner, a density of the cooling apertures104may be increased to increase film cooling of the heat shield82.

In some embodiments, the bulkhead74may also or alternatively be configured with a multi-walled structure (e.g., a hollow dual-walled structure) similar to that described above with respect to the inner wall76and the outer wall78. The bulkhead74, for example, may include a shell and a heat shield with one or more indentations as described above with respect to the heat shield82. Similarly, other components (e.g., a gaspath wall) within the turbine engine20may include a multi-walled structure as described above.

The terms “upstream”, “downstream”, “inner”, “outer”, “radial”, “circumferential” and “axial” are used to orientate the components of the turbine engine assembly62and the combustor64described above relative to the turbine engine20and its centerline22. A person of skill in the art will recognize, however, one or more of these components may be utilized in other orientations than those described above. The present invention therefore is not limited to any particular spatial orientations.

The turbine engine assembly62may be included in various turbine engines other than the one described above. The turbine engine assembly62, for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the turbine engine assembly62may be included in a turbine engine configured without a gear train. The turbine engine assembly62may be included in a geared or non-geared turbine engine configured with a single spool, with two spools (e.g., seeFIG. 1), or with more than two spools. The turbine engine may be configured as a turbofan engine, a turbojet engine, a propfan engine, or any other type of turbine engine. The present invention therefore is not limited to any particular types or configurations of turbine engines.