Patent Description:
Gas turbine engines can include a fan for propulsion air and to cool components. The fan also delivers air into a core engine where it is compressed. The compressed air is then delivered into a combustion section, where it is mixed with fuel and ignited. The combustion gas expands downstream over and drives turbine blades. Static vanes are positioned adjacent to the turbine blades to control the flow of the products of combustion. The blades and vanes are subject to extreme heat, and thus cooling schemes are utilized for each.

Some cooling schemes may employ cooling holes that communicate cooling flow to adjacent portions of the blades or vanes. Surfaces of the blades or vanes may include a coating.

<CIT> discloses an airfoil having a cooling passage between the pressure and section walls, with elongated pedestals arranged in the passage, interconnecting the pressure and suction walls. The pedestals are radially spaced from one another and a metering pedestal includes a portion arranged between the plane and trailing edge, the portion provided between adjacent pedestals.

<CIT> discloses an airfoil having an array of aluminized internal passageways, chromized up to a demarcation, and a method of coating such a component.

<CIT> discloses a method for measuring the surface quality of a lens comprising the steps of directing a beam of substantially collimated electromagnetic radiation onto the surface of the lens and measuring the intensity of the specularly reflected light from the surface of the lens.

According to a first aspect, the invention provides a gas turbine engine component as claimed in claim <NUM>.

In a further embodiment of any of the foregoing embodiments, each of the adjacent bounding pedestals and the common pedestal comprises a ceramic or metallic material, and the one or more coatings comprise a ceramic and/or metallic material.

In a further embodiment of any of the foregoing embodiments, the gas turbine engine component is an airfoil including an airfoil section extending in a radial direction from a platform section, extending in a chordwise direction between a leading edge and a trailing edge, and extending in a thickness direction between a pressure side and a suction side that join together at the leading and trailing edges.

In a further embodiment of any of the foregoing embodiments, the outlet is established along the trailing edge. Each of the adjacent bounding pedestals and the common pedestal comprises a metallic or ceramic material, and the one or more coatings includes a thermal barrier coating comprising a ceramic material and/or metallic material. The coated area ratio is less than or equal to <NUM>. The first and second branched sections exclude any pedestals between the common pedestal and the respective adjacent bounding pedestals.

In a further embodiment of any of the foregoing embodiments, a distance between the uncoated adjacent bounding pedestals progressively increases along the diffusion zones in a first direction towards the outlet.

In a further embodiment of any of the foregoing embodiments, a distance between the uncoated adjacent bounding pedestals progressively decreases along the diffusion zones in a first direction towards the outlet.

In a further embodiment of any of the foregoing embodiments, the adjacent bounding pedestals include first and second pedestals extending along respective longitudinal axes that are substantially parallel to each other. The first pedestal is associated with the first branched section. The second pedestal is associated with the second branched section. Facing walls of the common pedestal and the first pedestal are substantially parallel along a first length of the cooling passage between the first throat and the respective diffusion zone to establish a first metering zone. Facing walls of the common pedestal and the second pedestal are substantially parallel along the first length of the cooling passage between the second throat and the respective diffusion zone to establish a second metering zone. Facing walls of the adjacent bounding pedestals are substantially parallel along a second length of the merged section to establish a flat zone.

In a further embodiment of any of the foregoing embodiments, the longitudinal axes of the adjacent bounding pedestals establish a pitch, a first width is established as a widest distance across the first throat, a second width is established as a widest distance across the second throat, and wherein a ratio of a total of the first and second widths divided by the pitch is greater than or equal to <NUM> and is less than or equal to <NUM>.

In a further embodiment of any of the foregoing embodiments, the cooling passage excludes any pedestals across the first and second throats.

In a further embodiment of any of the foregoing embodiments, opposed faces of the external wall span between the facing walls of the adjacent bounding pedestals to bound the cooling passage. The opposed faces establish a first height at the outlet. A ratio of an average thickness of the one or more coatings along the opposed faces at the outlet divided by the first height is greater than or equal to <NUM>.

In a further embodiment of any of the foregoing embodiments, the adjacent bounding pedestals extend along respective longitudinal axes and along respective reference planes that bisects the adjacent bounding pedestals along the respective longitudinal axes. The longitudinal axes are substantially parallel to each other. A first cross-sectional area is established along the external wall surface at the outlet. The first cross-sectional area is defined between the reference planes and between the opposed faces, and one minus a ratio of a cross-sectional area of the outlet bounded by the coated outlet region divided by the first cross-sectional area defines a blockage ratio. The blockage ratio is greater than or equal to <NUM>.

In a further embodiment of any of the foregoing embodiments, the facing walls of the adjacent bounding pedestals bounding the cooling passage are filleted from the respective first and second inlets to the outlet.

In a further embodiment, a gas turbine engine includes an array of blades and an array of vanes spaced axially from the array of blades in a gas path. The array of blades are rotatable in the gas path, and an array of blade outer air seals (BOAS) are arranged about the array of blades to bound the gas path. At least one of the array of blades, the array of vanes and the array of BOAS includes the gas turbine engine component, wherein the external wall is between an internal wall surface and the external wall surface. The internal wall surface bounds an internal cavity. At least one pair of adjacent bounding pedestals are established in a thickness of the external wall. The adjacent bounding pedestals extend from the external wall surface to establish a cooling passage.

In a further embodiment of any of the foregoing embodiments, an airfoil section comprises the external wall. The airfoil section extends in a thickness direction between pressure and suction sides and extends in a chordwise direction between leading and trailing edges, and the outlet is established adjacent the trailing edge. The external wall comprises a ceramic or metallic material. The one or more coatings includes a thermal barrier coating comprising a ceramic material and/or a metallic material.

In a further embodiment of any of the foregoing embodiments, first and second inlets to the respective first and second branched sections are established between the adjacent bounding pedestals and the common pedestal. The first and second inlets are coupled to the internal cavity. The first and second branched sections taper from the respective first and second inlets in a first direction towards the outlet to establish the first and second throats. A distance between the adjacent bounding pedestals progressively increases along the diffusion zones in the first direction towards the outlet.

In a further embodiment of any of the foregoing embodiments, first and second inlets to the respective first and second branched sections are established between the adjacent bounding pedestals and the common pedestal, and the first and second inlets are coupled to the internal cavity. The first and second branched sections taper from the respective first and second inlets in a first direction towards the outlet to establish the first and second throats. A distance between the adjacent bounding pedestals progressively decreases along the diffusion zones in the first direction towards the outlet.

According to a further aspect of the invention, a method of fabricating a gas turbine engine as claimed in claim <NUM> is provided.

In a further embodiment of any of the foregoing embodiments, the gas turbine engine component is an airfoil including an airfoil section extending in a radial direction from a platform section, extending in a chordwise direction between a leading edge and a trailing edge, and extending in a thickness direction between a pressure side and a suction side that join together at the leading and trailing edges. The outlet is established along the trailing edge. Each of the adjacent bounding pedestals and the common pedestal comprises a metal or ceramic material, and the one or more coatings comprise a ceramic and/or metallic material.

In a further embodiment of any of the foregoing embodiments, the first and second branched sections taper from the respective first and second inlets in a first direction towards the outlet to establish the first and second throat. A distance between the adjacent bounding pedestals progressively increases along the diffusion zones in the first direction towards the outlet.

In a further embodiment of any of the foregoing embodiments, the first and second branched sections taper from the respective first and second inlets in a first direction towards the outlet to establish the first and second throat. A distance between the adjacent bounding pedestals progressively decreases along the diffusion zones in the first direction towards the outlet.

The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of an embodiment.

<FIG> illustrates an exemplary section of a gas turbine engine, such as the turbine section <NUM> of <FIG>. Although the disclosure primarily refers to the turbine section <NUM>, it should be understood that other portions of the engine <NUM> can benefit from the teachings disclosed herein, including airfoils in the compressor section <NUM> and combustor panels or liners in the combustor section <NUM>, and other portions of the engine <NUM> that may be subject to elevated temperature conditions during engine operation. Other systems can benefit from the teachings disclosed herein, including gas turbine engines and other systems lacking a fan for propulsion. In this disclosure, like reference numerals designate like elements where appropriate and reference numerals with the addition of one-hundred or multiples thereof designate modified elements that are understood to incorporate the same features and benefits of the corresponding original elements.

The turbine section <NUM> includes a plurality of components <NUM> arranged relative to the engine axis A, including a rotor <NUM>, one or more airfoils <NUM>, and one or more blade outer air seals (BOAS) <NUM>. Example airfoils <NUM> include blades <NUM>-<NUM> and vanes <NUM>-<NUM>. The rotor <NUM> is coupled to a rotatable shaft <NUM> (shown in dashed lines for illustrative purposes). The shaft <NUM> can be one of the shafts <NUM>, <NUM> of <FIG>, for example. The rotor <NUM> carries one or more blades <NUM>-<NUM> that are rotatable about the engine axis A in a gas path GP, such as the core flow path C.

Each airfoil <NUM> includes an airfoil section 62A extending in a spanwise or radial direction R from a first platform 62B. In the illustrative example of <FIG>, each blade <NUM>-<NUM> extends in the radial direction R from the platform 62B to a tip 62T, and each vane <NUM>-<NUM> extends in the radial direction R from the first (e.g., inner) platform 62B to a second (e.g., outer) platform 62C. The platforms 62B, 62C bound or define a portion of the gas path GP. The airfoil section 62A generally extends in a chordwise or axial direction X between a leading edge 62LE and a trailing edge 62TE, and extends in a circumferential or thickness direction T between pressure and suction sides 62P, <NUM>. The pressure and suction sides 62P, <NUM> are joined at the leading and trailing edges 62LE, 62TE. The root section 62R of the blade <NUM>-<NUM> is mounted to, or integrally formed with, the rotor <NUM>. The vane <NUM>-<NUM> can be arranged to direct or guide flow in the gas path GP from and/or towards the adjacent blade(s) <NUM>-<NUM>.

Each BOAS <NUM> can be spaced radially outward from the tip 62T of the blade <NUM>-<NUM>. The BOAS <NUM> can include an array of seal arc segments that are circumferentially distributed or arranged in an annulus about an array of the airfoils <NUM> to bound the gas path GP.

The turbine section <NUM> includes at least one array of airfoils <NUM>, including at least one array of blades <NUM>-<NUM> and at least one array of vanes <NUM>-<NUM>, and at least one array of BOAS <NUM> arranged circumferentially about the engine axis A. The array of vanes <NUM>-<NUM> are spaced axially from the array of blades <NUM>-<NUM> relative to the engine axis A. The tips 62T of the blades <NUM>-<NUM> and adjacent BOAS <NUM> are arranged in close radial proximity to reduce the amount of gas flow that escapes around the tips 62T through a corresponding clearance gap.

The turbine section <NUM> includes a cooling arrangement <NUM> for providing cooling augmentation to the components <NUM> during engine operation. The cooling arrangement <NUM> includes one or more cooling cavities or plenums P1, P2 defined by a portion of the engine static structure <NUM> such as the engine case <NUM>. The plenum P2 can be at least partially defined or bounded by a rotatable portion of the engine <NUM>, such as the rotor <NUM>. One or more cooling sources CS (one shown) are configured to provide cooling air to the plenums P1, P2. The plenums P1, P2 are configured to receive pressurized cooling flow from the cooling source(s) CS to cool portions of the airfoils <NUM> and/or BOAS <NUM>. Cooling sources CS can include bleed air from an upstream stage of the compressor section <NUM> (<FIG>), bypass air, or a secondary cooling system aboard the aircraft, for example. Each of the plenums P1, P2 can extend in a circumferential or thickness direction T between adjacent airfoils <NUM> and/or BOAS <NUM>.

<FIG> illustrate an exemplary gas turbine engine component <NUM> including a cooling arrangement <NUM>. The component <NUM> can be a combustion liner incorporated into the combustor section <NUM>, or a BOAS <NUM> or airfoil <NUM> such as a blade <NUM>-<NUM> or vane <NUM>-<NUM> incorporated into the turbine section <NUM> of <FIG> and <FIG>, for example. In the illustrative example of <FIG>, the component <NUM> is an airfoil <NUM> shown as a blade <NUM>-<NUM>. The blade <NUM>-<NUM> can be a turbine blade incorporated into one or more rows of the turbine section <NUM>, for example.

Referring to <FIG>, the airfoil <NUM> includes an airfoil section 162A extending in a radial direction R from a platform section 162B (<FIG>). The airfoil section 162A extends in a chordwise direction X between a leading edge 162LE and a trailing edge 162TE. The airfoil section 162A extends in a thickness direction T between a pressure side 162P and a suction side <NUM> joined together at the leading and trailing edges 162LE, 162TE. The airfoil <NUM> can include one or more external walls 162E and one or more internal walls 162N (<FIG>) defined within a thickness of the airfoil section 162A and/or platform section 162B. Surfaces along the external walls 162E of the airfoil section 162A and the platform(s) 162B establish an external surface contour 162SC that interacts with gases in a gas path GP during operation, such as the core flow path C of <FIG>.

The component <NUM> can be made of various materials including metallic, composite and/or non-metallic materials. Example metallic materials include high temperature metals or alloys, such as a nickel-based super alloy. Single crystal and directionally solidified metallic materials can be utilized. The component <NUM> can be made of a ceramic or ceramic matrix composite (CMC) material formed from one or more layers of a CMC layup.

Referring to <FIG>, with continuing reference to <FIG>, the external wall 162E extends between an external wall surface 162SE and another opposed external wall surface 162SE and/or internal wall surface 162SI. In the illustrated example of <FIG>, the airfoil section 162A includes external walls 162E that establish the external surface contour 162SC.

The component <NUM> defines one or more plenums or internal cavities <NUM> in a thickness of the airfoil section 162A or another portion of the component <NUM>. Each of the cavities <NUM> can be fluidly coupled to a coolant source CS (shown in dashed lines for illustrated purposes). The internal cavities <NUM> can serve as impingement cavities and/or upstream feeding cavities for receiving cooling flow F from the coolant source CS. Each internal wall surface 162SI can bound one of the internal cavities <NUM>.

The component <NUM> defines one or more cooling channels or passages <NUM> for cooling portions of the component <NUM>. At least some of the cooling passages <NUM> are defined in the external wall(s) 162E. Each of the cooling passages <NUM> extends between a respective inlet <NUM> and outlet <NUM>. The cooling passage <NUM> can convey cooling flow F to provide cooling augmentation to adjacent portions of the component <NUM>.

In the illustrative example of <FIG>, one or more (or each) of the outlets <NUM> are established along or otherwise adjacent to the trailing edge 162TE. In examples, the outlet <NUM> is established at a position along the external wall surface 162SE at a distance of less than about <NUM> percent of a chord length from the trailing edge 162TE. For the purposes of this disclosure, the chord length is defined as a minimum distance between the leading and trailing edges 162LE, 162TE at the same radial position as the respective outlet <NUM>. For purposes of this disclosure, the terms "about," "approximately" and "substantially" mean ±<NUM>% of the stated value or relationship unless otherwise indicated. It should be understood that one or more of the outlets <NUM> can be established along other portions of the airfoil section 162A, the platform 162B, and other portions of the component <NUM> that may benefit from cooling augmentation. Other exemplary locations of passages <NUM>' are shown in dashed lines for illustrative purposes.

Referring to <FIG>, with continued reference to <FIG>, the component <NUM> can include one or more transfer (or augmentation) features <NUM> in a wall 160E of the component <NUM>, such as the external wall(s) 162E. The transfer features <NUM> include bounding pedestals <NUM> and common (or metering) pedestals <NUM> dimensioned to span between opposed walls of the component <NUM>. Other exemplary transfer features can include turbulators such as trip strips, bulges and dimples. The pedestals <NUM>, <NUM> can be arranged in a row with respect to the radial direction R, as illustrated by <FIG>, or in another orientation.

Referring to <FIG>, with continuing reference to <FIG>, the pedestals <NUM>, <NUM> are established in a thickness of the external wall 162E. The component <NUM> includes at least one row of bounding pedestals <NUM> that establish a row of cooling passages <NUM>. The row of pedestals <NUM> and cooling passages <NUM> are distributed in a direction DY and are at least partially axially aligned in a direction DX perpendicular to a height of the pedestals <NUM> in a direction DZ. The directions DX, DY, DZ can correspond to the chordwise, radial and thickness directions X, R, T, for example. The cooling arrangement <NUM> is established such that the bounding pedestals <NUM> alternate in sequence with the common pedestals <NUM>, as illustrated in <FIG>. The alternating pedestal arrangements disclosed herein may serve to convey sufficient diffusion flow in instances in which relatively thick coatings are disposed along and into the respective outlets.

The exemplary cooling arrangement <NUM> includes first, second and third bounding pedestals <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> and first and second common pedestals <NUM>-<NUM>, <NUM>-<NUM> arranged in a row. The bounding pedestals <NUM> are arranged in adjacent pairs to establish respective cooling passages <NUM> therebetween. In the illustrative examples of <FIG>, two common pedestals <NUM>-<NUM>, <NUM>-<NUM> are arranged between the adjacent pedestals <NUM> of the two pairs of adjacent bounding pedestals <NUM>-<NUM>/<NUM>-<NUM>, <NUM>-<NUM>/<NUM>-<NUM> to establish two adjacent cooling passages <NUM>-<NUM>, <NUM>-<NUM>, with pedestal <NUM>-<NUM> being common to both pairs <NUM>-<NUM>/<NUM>-<NUM>, <NUM>-<NUM>/<NUM>-<NUM>. Fewer or more than two pairs of bounding pedestals <NUM> can be utilized to establish the cooling arrangement <NUM>, such as only one pair of bounding pedestals <NUM>.

The pedestals <NUM>, <NUM> can have various geometries to establish a profile of the respective cooling passages <NUM>. In the illustrative example of <FIG>, each of the bounding pedestals <NUM> and common pedestals <NUM> has generally spear-shaped geometry. It should be understood that other pedestal geometries can be utilized to establish the cooling passages, including any of the geometries disclosed herein.

Each pedestal <NUM>, <NUM> can be elongated and extends along a respective longitudinal axis LA that intersects opposed upstream and downstream ends of the respective pedestal <NUM>, <NUM>. The longitudinal axis LA can have a major component in the direction DX. The bounding pedestals <NUM> extend along the longitudinal axes LA from the external wall surface 162SE to an opposed internal wall surface 162SI to establish the respective cooling passage <NUM>. Each pair of bounding pedestals <NUM> (e.g., <NUM>-<NUM>, <NUM>-<NUM>) are directly adjacent to each other with respect to a position along the outlet <NUM>.

The common pedestals <NUM> are situated between respective pairs of the bounding pedestals <NUM> to divide a portion of the respective cooling passage <NUM>. The common pedestal <NUM> is directly adjacent to each bounding pedestal <NUM> in the respective pair of pedestals <NUM>, as illustrated by pedestals <NUM>-<NUM>, <NUM>-<NUM> and pedestal <NUM>-<NUM>.

Each cooling passage <NUM> includes a first inlet <NUM> and a second inlet <NUM>. The first and second inlets <NUM>, <NUM> are established between the upstream edges of the common pedestal <NUM> and bounding pedestals <NUM> that are directly adjacent to the common pedestal <NUM>. Each inlet <NUM>, <NUM> can be coupled to the internal cavity <NUM> along the internal wall surface 162SI to convey cooling flow F to the cooling passage <NUM>.

Each outlet <NUM> can be established along the external wall surface 162SE of the component <NUM>, such as along the trailing edge 162TE, as illustrated by <FIG>, and <FIG>. In the illustrative example of <FIG>, one or more cooling passages <NUM> established by the adjacent pedestals <NUM> are fluidly isolated between the inlets <NUM>, <NUM> and outlet <NUM> with respect to other directly adjacent cooling passage(s) <NUM>, as illustrated by cooling passages <NUM>-<NUM>, <NUM>-<NUM>.

The common pedestals <NUM> are situated between respective pairs of the bounding pedestals <NUM> to divide a portion of the respective cooling passage <NUM> between at least two branched sections 170B. The common pedestal <NUM> is spaced apart from the outlet <NUM> such that no other pedestals are arranged between facing walls 176W of the adj acent pedestals <NUM> bounding the respective cooling passage <NUM> at the outlet <NUM>, as illustrated by the pair of pedestals <NUM>-<NUM>, <NUM>-<NUM> in <FIG>.

For example, the common pedestal <NUM>-<NUM> is situated between the pair of the bounding pedestals <NUM>-<NUM>, <NUM>-<NUM> to establish a first branched section 170B-<NUM> and a second branched section 170B-<NUM> of the cooling passage <NUM>. The branched sections <NUM> include a first branched section 170B-<NUM> and a second branched section 170B-<NUM> on opposed sides of the common pedestal <NUM>. The first pedestal <NUM>-<NUM> is associated with the first branched section 170B-<NUM>, and the second pedestal <NUM>-<NUM> is associated with the second branched section 170B-<NUM>. The branched sections 170B-<NUM>, 170B-<NUM> join together or merge at a merged section <NUM> of the cooling passage <NUM> at the downstream end of the common pedestal <NUM>-<NUM>. The merged section <NUM> establishes an outlet <NUM> along the external wall surface 162SE between the bounding pedestals <NUM>-<NUM>, <NUM>-<NUM>. The merged section <NUM> interconnects the first and second branched sections 170B-<NUM>, 170B-<NUM> and the outlet <NUM>, and extends in the direction DX between a terminal end of the common pedestal <NUM> and the outlet <NUM>.

A respective meter or throat <NUM> is established along each of the branched sections 170B to meter flow F through the cooling passage <NUM> (shown in dashed lines for illustrative purposes). The bounding pedestals <NUM>-<NUM>, <NUM>-<NUM> and the common pedestal <NUM>-<NUM> are dimensioned such that first and second throats <NUM>-<NUM>, <NUM>-<NUM> are established along the respective branched sections 170B-<NUM>, 170B-<NUM>.

The throats <NUM>-<NUM>, <NUM>-<NUM> establish a minimum cross-sectional area along the respective branched sections 170B-<NUM>, 170B-<NUM> between the inlets <NUM>, <NUM> and merged section <NUM>, and serve to meter flow through the cooling passage <NUM>. The throats <NUM> and outlet <NUM> can have various geometries, such as a generally racetrack-shaped or elongated geometry as illustrated in <FIG>.

The pedestals <NUM>, <NUM> can be dimensioned to establish a relatively compact arrangement. The longitudinal axis LA of the pair of adjacent pedestals <NUM> establish a respective pitch P (<FIG>). The pitch P may be established with respect to the center of the adjacent pedestals <NUM> along the respective longitudinal axes LA. A first width W1 is established as a widest distance across the first throat <NUM>-<NUM>, and a second width W2 is established as a widest distance across the second throat <NUM>-<NUM>. The first and second widths W1, W2 are taken at a widest distance across the throats <NUM>-<NUM>, <NUM>-<NUM> to account for any contouring of the walls 176W, 177W at the position of the throats <NUM>-<NUM>, <NUM>-<NUM>. The pedestals <NUM>, <NUM> can be dimensioned such that a ratio of a total of the first and second widths W1, W2 divided by the pitch P is greater than or equal to about <NUM>, or more narrowly above about <NUM> and less than or equal to about <NUM>.

Facing walls 176W of the bounding pedestals <NUM> and facing walls 177W of the common pedestal <NUM> can be dimensioned such that the branched sections 170B-<NUM>, 170B-<NUM> taper inwardly from the respective inlet <NUM>, <NUM> in a first direction D1 towards the outlet <NUM> to establish the respective throats <NUM>-<NUM>, <NUM>-<NUM>. The bounding pedestals <NUM> and common pedestal <NUM> can be dimensioned such that the throats <NUM>-<NUM>, <NUM>-<NUM> are established at substantially the same axial position relative to the direction DX and are spaced apart from the respective inlets <NUM>, <NUM>, as illustrated in <FIG>. In other examples, the throats <NUM>-<NUM>, <NUM>-<NUM> are established at the respective inlets <NUM>, <NUM> and/or are established at different axial positions The cooling arrangement <NUM> can be established such that the branched sections 170B-<NUM>, 170B-<NUM> exclude any pedestals between the common pedestal <NUM>-<NUM> and the respective adjacent branched pedestals <NUM>-<NUM>, <NUM>-<NUM>, including across the respective throats <NUM>-<NUM>, <NUM>-<NUM>, as illustrated in <FIG>.

Each of the branched sections 170B extends along a respective passage axis PA between a respective inlet <NUM>, <NUM> and the merged section <NUM>. The passage axes PA of the branched sections 170B-<NUM>, 170B-<NUM> can be substantially parallel to one another, as illustrated in <FIG>, or can be transverse to one another. The passage axis PA can have a major component in the direction DX. The longitudinal axis LA of the pedestals <NUM>-<NUM>, <NUM>-<NUM> and/or common pedestal <NUM> can be substantially parallel to each other, as illustrated in <FIG>.

Facing walls 176W of the pedestals <NUM> and facing walls 177W of the pedestal <NUM> can be dimensioned such that the first and second branched sections 170B, 170B expand outwardly in the first direction D1 from the respective throats <NUM> and towards the outlet <NUM> to establish diffusion zones <NUM> along the respective branched sections 170B. A cross-sectional area at an exit of the diffusion zone <NUM> is greater than a cross-sectional area of the respective throat <NUM> such that the diffusion zone <NUM> serves to convey diffused cooling flow F from the branched sections 170B to the merged section <NUM> of the cooling passage <NUM>.

In the illustrative example of <FIG>, a first diffusion zone <NUM>-<NUM> is established along the first branched section 170B-<NUM> between the first throat <NUM>-<NUM> and the merged section <NUM>, and a second diffusion zone <NUM>-<NUM> is established along the second branched section 170B-<NUM> between the second throat <NUM>-<NUM> and the merged section <NUM>. The diffusion zones <NUM>-<NUM>, <NUM>-<NUM> interconnect the respective throats <NUM>-<NUM>, <NUM>-<NUM> to the merged section <NUM> and outlet <NUM>. An entrance 180E to each diffusion zone <NUM> can be established a distance from the throat <NUM>, as illustrated by <FIG>, or can be established at the respective throat <NUM>, as illustrated by the cooling arrangement <NUM> in <FIG>. The diffusion zones <NUM> are dimensioned to convey diffused cooling flow F to the outlet <NUM>. The outlet <NUM> can be dimensioned to eject or convey the diffused cooling flow F to various portions of the component <NUM> during operation, such as along the external wall surface 162SE of the component <NUM> to provide film cooling augmentation, for example.

The bounding pedestals <NUM> can have various geometries to establish a perimeter of the cooling passage <NUM>. In the illustrative example of <FIG>, facing walls 176W of the pedestals <NUM> are dimensioned to establish a converging pedestal arrangement <NUM> and a diverging cooling channel or passage <NUM> relative to a general direction of flow through the cooling arrangement <NUM>. The width of the pedestals <NUM> generally decreases in the direction D1 to establish the converging pedestal arrangement <NUM> and diverging cooling passage <NUM>. The facing walls 176W of the pedestals <NUM> establish a minimum width WA and a maximum width WB along a length of the cooling passage <NUM>. The minimum width WA can be established at a position substantially aligned with the throats <NUM>, and the maximum width WB can be established at a position substantially aligned with the outlet <NUM>, as illustrated in <FIG>. The maximum width WB is greater than the minimum width WA such that a distance between the facing walls 176W diverges in the first direction D1 from a position of the minimum width WA towards a position the maximum width WB.

A thickness of each pedestal <NUM>, <NUM> can be dimensioned such that the pedestals <NUM>, <NUM> taper along the longitudinal axis LA between the throat <NUM> and the outlet <NUM> to establish the diffusion zone <NUM>. Each of the walls 176W can slope from the first length L1 to establish an angle α. Each of the walls 177W can slope from the first length L1 to establish an angle β. The angle α can be established with respect to a reference plane REFA extending along the first length L1 of the wall 176W. The angle β can be established with respect to a reference plane REFB extending along the first length L1 of the wall 177W.

The reference planes REFA and/or REFB can be substantially parallel to the passage axis PA and/or longitudinal axis LA of the respective pedestal <NUM>, <NUM>. Angle α and/or angle β can be greater than <NUM> degrees to establish the diffusion zones <NUM>. In examples, the angles α, β are at least about <NUM> degree, or more narrowly are less than or equal to about <NUM> or <NUM> degrees. The angles α, β disclosed herein can be utilized to establish sufficient velocities of the cooling flow F which may more closely match a velocity of gases in the gas path GP (<FIG>). The diffusion zones <NUM> can be utilized to provide sufficient cooling and reduce a likelihood of metering due to blockage at the outlet <NUM>.

The diffusion zone <NUM> extends along a third length L3. A width WC is established at the entrance 180E of the diffusion zone <NUM>, and a width WD is established at an exit of the diffusion zone <NUM>. In the illustrative example of <FIG>, the width WD is greater than the width WC such that a distance or width between the bounding pedestals <NUM> progressively increases along the diffusion zones <NUM> in the first direction D1 towards the outlet <NUM>.

The facing walls 176W of the bounding pedestals <NUM> can be substantially parallel along a length of the merged section <NUM> to establish a flat zone <NUM>. A distance between the facing walls 176W of the bounding pedestals <NUM>, excluding any coating thicknesses, can be approximately equal along a length of the flat zone <NUM> such that the cooling passage <NUM> has a substantially constant cross-sectional area along the length of the flat zone <NUM>. The flat zone <NUM> is established between the diffusion zones <NUM> and outlet <NUM>. The flat zone <NUM> may reduce variation in dimensioning of the outlets <NUM> that may be otherwise caused by shifting or movement of a casting core during formation of the cooling arrangement <NUM>. In other examples, the flat zone <NUM> is omitted and the diffusion zone <NUM> establishes the outlet <NUM>, as illustrated by the cooling arrangement <NUM> of <FIG>.

Pedestals <NUM>-<NUM>, <NUM>-<NUM> and common pedestal <NUM> can extend along respective reference planes REF1 to REF3 (<FIG> and <FIG>). The reference planes REF1 to REF3 are established along the respective longitudinal axes LA and bisect the respective pedestals <NUM>-<NUM>, <NUM>-<NUM>, <NUM>, as illustrated by <FIG>. The pedestals <NUM>-<NUM>, <NUM>-<NUM>, <NUM> can be substantially symmetrical along the respective reference planes REF1 to REF3, as illustrated by <FIG>.

The bounding pedestals <NUM> can be dimensioned such that the facing walls 176W are substantially parallel along a first length L1 of the cooling passage <NUM> between the throats <NUM> and entrances 180E of the respective diffusion zones <NUM> to establish respective metering zones <NUM> (indicated at <NUM>-<NUM>, <NUM>-<NUM>) and are substantially parallel along a second length L2 of the cooling passage <NUM> between the diffusion zones <NUM> and outlet <NUM> to establish the flat zone <NUM>, as illustrated in <FIG>. In the illustrative example of <FIG>, no other pedestals are arranged between the facing walls 176W of the pedestals <NUM> and the facing walls 177W of the pedestal <NUM> bounding the respective branched sections 170B, including across the throat <NUM>. Dimensioning the pedestals <NUM>, <NUM> to have the metering zones <NUM> may provide more relatively consistent flow between two or more components <NUM>. In examples, the first length L1 is between <NUM>-<NUM> hydraulic diameters. A "hydraulic diameter" can be calculated as <NUM> times the flow area divided by the wetted perimeter of the cooling passage.

The facing walls 176W, 177W of the pedestals <NUM>, <NUM> can be partially or completely filleted. The facing walls 176W can be filleted along at least a portion of the cooling passage <NUM> between the respective first and second inlets <NUM>, <NUM> and the outlet <NUM>, including along the throats <NUM> and outlet <NUM>, as illustrated in <FIG>. Fillets 176F, 177F of the respective pedestals <NUM>, <NUM> establish junctions between the facing walls 176W, 177W and opposed faces <NUM>, <NUM> bounding the cooling passage <NUM>, as illustrated in <FIG>. The fillets 176F, 177F can be utilized to reduce localized stress concentrations in the component <NUM>. The fillets 176F, 177F may improve filling of a respective core during formation of the cooling passages. Partial fillets may reduce weight as compared to full fillets. Full fillets may provide relatively lower stress concentrations with respect to partial fillets.

The component <NUM> includes one or more coatings <NUM> disposed or formed along various surfaces of the component <NUM>. In the illustrative example of <FIG>, one or more coatings <NUM> can be disposed along the external walls surface 162SE (<NUM>' shown in dashed lines for illustrative purposes). At least one coating <NUM> is disposed into and along one or more of the outlets <NUM> to establish a coated outlet region <NUM> of the merged section <NUM> of the respective cooling passage <NUM>, as illustrated by <FIG> and <FIG>. In the illustrative example of <FIG>, the coating <NUM> is disposed along a perimeter 174P of the respective outlet <NUM>, and along at least a portion of the length L2 of the flat zone <NUM>. The coated outlet region <NUM> interconnects the outlet <NUM> and upstream portions of the cooling passage <NUM> including the diffusion zones <NUM>. In the illustrative example of <FIG>, the coating <NUM> is disposed along at least a portion of the second length L2 of the cooling passage <NUM> to establish the coated outlet region <NUM>. The coating <NUM> can taper in the direction DX from the respective outlet <NUM> towards the respective inlet <NUM>. The pedestals <NUM>, <NUM> can be dimensioned such the throats <NUM> and diffusion zones <NUM> substantially or completely exclude any thermal barrier (or other) coatings.

A dimension of each of the throats <NUM>-<NUM>, <NUM>-<NUM> can be selected with respect to a predetermined thickness of the coating <NUM>, such as an expected maximum and/or average thickness of the coating <NUM> associated with the coated outlet region <NUM>. Each of the throats <NUM>-<NUM>, <NUM>-<NUM> can be dimensioned to establish a minimum cross-sectional area of the coated cooling passage <NUM> such that the throats <NUM>-<NUM>, <NUM>-<NUM> meter cooling flow F through the cooling passage <NUM> in operation.

Various materials can be utilized for the coatings and transfer features disclosed herein, including metallic and non-metallic materials. Example metallic and non-metallic materials include any of the materials disclosed herein. The transfer features <NUM> including pedestals <NUM>, <NUM> can be made of a first material, and each coating <NUM> can be made of a second material. The second material can be the same or can differ from the first material in composition and/or construction. In examples, the external walls 162E and each of the pedestals <NUM>, <NUM> of the component <NUM> are made of a ceramic material such as a ceramic matrix composite (CMC) or can are made out of a metallic material such as a nickel based alloy. In examples, the coating(s) <NUM> are made of a ceramic material and/or metallic material. Each coating <NUM> can be established by one or more layers. Coating(s) <NUM> along the external surfaces 162SE can be ceramic coatings and serve as a thermal barrier coating to at least partially insulate the component <NUM> from relatively hot gases in the gaspath GP (<FIG>) in operation. Coating(s) <NUM> along the external surfaces 162SE can also be metallic coatings such as diffusion or overlay coatings that provide oxidation and/or corrosion resistance. These metallic coatings can also serve as a bond coating layer to facilitate the adhesion of the ceramic thermal barrier coating to the part substrate.

Referring to <FIG>, a local minimum cross-sectional area A1, A2 of the branched sections 170B-<NUM>, 170B2 of the cooling passage <NUM> are established along the respective throats <NUM>-<NUM>, <NUM>-<NUM> (A1, A2 shown in dashed lines in <FIG> for illustrative purposes). A local minimum cross-sectional area A3 of the cooling passage <NUM> along the coated outlet region <NUM> can be established at the outlet <NUM> (A3 shown in dashed lines in <FIG> for illustrative purposes). The minimum cross-sectional area of the cooling passage A3 along the coated outlet region <NUM> divided by a total of the minimum cross-sectional areas A1, A2 of the first and second throats <NUM>-<NUM>, <NUM>-<NUM> establishes a coated area ratio expressed as A3:(A1+A2). In examples, the coated area ratio is greater than or equal to about <NUM>, or more narrowly is less than or equal to <NUM>. In examples, the coated area ratio is less than or equal to about <NUM>, such as about <NUM>.

The cooling arrangement <NUM> can be dimensioned to establish a relatively compact arrangement that provide sufficient rigidity of the component <NUM> and sufficient cooling flow ejected from the outlet <NUM>. For example, referring to <FIG>, opposed faces <NUM>, <NUM> of the wall 160E span or otherwise extend between the facing walls 176W of the adjacent pedestals <NUM> to bound the cooling passage <NUM>. The opposed faces <NUM>, <NUM> establish a first height H1 at the outlet <NUM>. In examples, the coating <NUM> is relatively thick such that a ratio of an average thickness of the coating <NUM> along the opposed faces <NUM>, <NUM> at the outlet <NUM> divided by the first height H1 is greater than or equal to about <NUM>, or more narrowly less than or equal to about <NUM>. The ratio can be greater than or equal to <NUM>, and can be less than or equal to about <NUM>. In other examples, the coating <NUM> is relatively thin such that the ratio is less than <NUM>. The length L2 along the flat zone <NUM> can be greater than the first height H1 such that the throats <NUM> are established upstream of the coated outlet region <NUM>.

A relationship between the throats <NUM> and the outlet <NUM> excluding the coatings <NUM> be established. A cross-sectional area A4 can be established between the facing walls 176W and opposed faces <NUM>, <NUM> along the outlet <NUM> (A4 shown in dashed lines in <FIG> for illustrative purposes). The cross-sectional area A4 along the outlet <NUM> divided by an arithmetic additive total of the cross-sectional areas A1, A2 of the throats <NUM> establishes an uncoated area ratio expressed as A4:(A1+A2). In examples, the uncoated area ratio is greater than or equal to about <NUM>, or more narrowly less than or equal to about <NUM>, such as between about <NUM> and about <NUM>, or about <NUM>. In examples, the cooling arrangement <NUM> is established such that a ratio of A3:A4 is greater than about <NUM>, or more narrowly is less than about <NUM>.

The disclosed coated and uncoated area ratios can improve durability by establishing sufficient coating <NUM> thickness and cooling augmentation by the cooling passage <NUM>, and can improve aerodynamics by establishing exit velocities of cooling flow F ejected by the outlet <NUM> to closely match velocities of gases in the gas path GP (<FIG>) to reduce losses that may be otherwise caused by mixing, turbulence, and flow separation, for example.

The pedestals <NUM> can be arranged relatively close which may increase structural rigidity along adjacent portions of the component <NUM>. A cross-sectional area AP is established between the reference planes REF1, REF2 of the adjacent pedestals <NUM>-<NUM>, <NUM>-<NUM> and opposed faces <NUM>, <NUM> along an external wall surface 160SE of the component <NUM> at the outlet <NUM> (shown in dashed lines of <FIG> for illustrative purposes). The adjacent pedestals <NUM> and respective cooling passages <NUM> can be dimensioned such that one minus the cross-sectional area A3 of the outlet <NUM> bounded by the coated outlet region <NUM> of the respective cooling passage <NUM> divided by the cross-sectional area AP defines a blockage ratio (<NUM>-A3/AP). In examples, the blockage ratio (<NUM>-A3/AP) is greater than or equal to about <NUM>, or more narrowly is less than or equal to about <NUM>, such as about <NUM>. One or more (or each) adjacent pair of pedestals and one or more (or each) cooling passage can be dimensioned according to any of the ratios and other parameters disclosed herein.

Other geometries of the transfer features can be utilized to establish the cooling passages. <FIG> illustrate example converging pedestal arrangements <NUM>, <NUM>, <NUM>, <NUM> and respective diverging cooling passages <NUM>, <NUM>, <NUM>, <NUM>. In the illustrative cooling arrangement <NUM> of <FIG>, facing walls 276W, 277W of pedestals <NUM>, <NUM> are dimensioned such that the metering zones are omitted. Entrances to diffusion zones <NUM> are established at respective throats <NUM>.

In the illustrative cooling arrangement <NUM> of <FIG>, facing walls 376W of pedestals <NUM> are dimensioned such that the flat zone is omitted, and the facing walls 376W slope from the diffusion zones <NUM> to the outlet <NUM>. Common pedestal <NUM> is dimensioned such that a terminal end 377T axially overlaps with a coated outlet region <NUM> of the cooling passage <NUM> with respect to direction DX. In the illustrative example of <FIG>, common pedestal <NUM> has a substantially elliptical or oblong geometry. In the illustrative example of <FIG>, common pedestal <NUM> has a substantially circular geometry.

<FIG> illustrate a gas turbine engine component <NUM> including a cooling arrangement <NUM> according to another example. In the illustrative example of <FIG>, walls 676W of the pedestals <NUM> are dimensioned to establish a diverging pedestal arrangement <NUM> and converging cooling passage <NUM> arrangement. The width of the pedestals <NUM> generally increases in the direction D1 to establish the diverging pedestal arrangement <NUM>, which may be utilized to more closely match a flow area at the throats <NUM> with a flow area at the outlet <NUM>. The facing walls 676W of the pedestals <NUM> establish a minimum (e.g., upstream) width WA and a maximum (e.g., outlet) width WB. The minimum width WA can be established at a position substantially aligned with the throats <NUM>, and the width WB is established at a position substantially aligned with an outlet <NUM> such that the position associated with the minimum width WA is upstream of the position associated with the width WB, as illustrated in <FIG>. The width WB is less than the minimum width WA such that a distance between the facing walls 676W converges in the first direction D1 from the minimum width WA position towards the maximum width WB position. The pedestals <NUM> can be dimensioned such that a distance between uncoated portions of the walls 676W of the respective pedestal <NUM> progressively increases along diffusion zones <NUM> in a first direction D1 towards an outlet <NUM>, as illustrated by <FIG>.

Each of the walls 676W can slope from a respective metering zone <NUM> to establish an angle γ. The angle γ can be established with respect to a reference plane REFG extending along a length of the wall 676W establishing the metering zone <NUM>. The angle γ can be greater than <NUM> degrees to establish the diffusion sections <NUM>. In examples, the angle γ is least about <NUM> degree, or more narrowly is less than or equal to about <NUM> or <NUM> degrees. The angles γ disclosed herein can be utilized to establish sufficient velocities of the cooling flow F which may more closely match a velocity of gases in the gas path GP (<FIG>).

One or more coatings <NUM> are disposed along and into the outlet <NUM> to establish a coated outlet region <NUM>. Opposed faces <NUM>, <NUM> establish a first height H1 at the outlet <NUM> (<FIG>). A ratio of an average thickness of the coating <NUM> along the opposed faces <NUM>, <NUM> at the outlet <NUM> divided by the first height H1 can be established. The ratio can include any of the values disclosed herein. In examples, the ratio is greater than <NUM>, and is less than <NUM>.

<FIG> illustrate a gas turbine engine component <NUM> including a cooling arrangement <NUM> according to another example. Walls 776W of pedestals <NUM> and walls 777W of pedestal <NUM> are dimensioned to establish both a diverging and converging combined pedestal arrangement <NUM>. The pedestals <NUM> are dimensioned such that a distance between uncoated portions of the adjacent pedestals <NUM> progressively decreases along diffusion zones <NUM> in a first direction D1 towards an outlet <NUM>. Each of the walls 776W can slope from a respective metering zone <NUM> to establish an angle γ, which may be dimensioned according to any of the values disclosed herein. In the illustrative cooling arrangement <NUM> of <FIG>, the facing walls 776W of the pedestals <NUM> are dimensioned such that the flat zone is omitted, and the facing walls 776W continue to slope from the diffusion zones <NUM> to the outlet <NUM>. In the illustrative example of <FIG>, the throats <NUM> and outlet <NUM> have a substantially rectangular geometry.

<FIG> illustrates another example cooling arrangement <NUM> established by a converging and diverging pedestal arrangement <NUM>. Facing walls 876W of pedestals <NUM> are dimensioned to establish a flat zone <NUM> extending to an outlet <NUM>. Common pedestal <NUM> is dimensioned such that a terminal end 877T axially overlaps with a coated outlet region <NUM> of the cooling passage <NUM> with respect to direction DX.

<FIG> illustrate exemplary casting cores <NUM>, <NUM> that can be utilized for establishing a cooling arrangement, including any of the cooling arrangements disclosed herein. Core <NUM>/<NUM> can include a main body 990A/1090A and one or more branches 990B/1090B that extend outwardly from the main body 990A/1090A to a respective free end 990E/1090E. Adjacent branches 990B/1090B can establish a respective void 990V/990V therebetween. The branches 990B/1090B can establish a respective cavity 990C/1090C. A geometry of the voids 990V/1090V and cavities 990C/1090C can correspond to a geometry of any of the transfer features or pedestals disclosed herein, and a geometry of the branches 990B/1090B can correspond to any of the cooling passages disclosed herein. The free ends 990E/1090E can correspond a geometry of any of the outlets disclosed herein, including outlets along a trailing edge of a corresponding airfoil. Various materials can be utilized to form the cores <NUM>, <NUM>, such as a refractory metal core (RMC) or ceramic core.

<FIG> illustrates an exemplary process in a flowchart <NUM> for fabricating a gas turbine engine component including any of the components disclosed herein. The component <NUM>, <NUM> are referenced for illustrative purposes. However, it should be appreciated that the process <NUM> can be utilized in combination with any of the cooling arrangements disclosed herein. Although only four steps 1192A-1192D are shown, it should be understood that fewer or more than four steps can be utilized, and each step 1192A-1192D may encompass more than one step.

With reference to <FIG> and <FIG>, one or more walls that define the internal cavities <NUM>/<NUM> can be established at step 1192A, including outer walls such as the external walls 162E/662E of the component <NUM>/<NUM>. In other examples, step 1192A is omitted. In some examples, steps 1192A and 1192B occur simultaneously. The internal cavities <NUM>/<NUM> can be bounded by an external wall 162E/662E of the component <NUM>/<NUM>.

At step 1192B, one or more walls 176W/676W, 177W/677W of the pedestals <NUM>/<NUM> that define the cooling passages <NUM>/<NUM> of a cooling arrangement <NUM>/<NUM> are established. The walls 176W/676W, 177W/677W of the pedestals <NUM>/<NUM> and associated cooling passages <NUM>/<NUM> can be established in an outer wall of the component <NUM>/<NUM>, such as the external wall 162E/662E of the component <NUM>/<NUM>. Each cooling passage <NUM>/<NUM> includes a pair of inlets <NUM>/<NUM>, <NUM>/<NUM> coupled to the internal cavity <NUM>/<NUM>, which can serve as an upstream feed cavity that conveys cooling flow to each cooling passage <NUM>/<NUM> in operation. The adjacent pedestals <NUM>/<NUM> can extend from the external wall surface 162SE/662SE of the external wall 162E/662E to establish an outlet <NUM>/<NUM> of the cooling passage <NUM>/<NUM>. A common pedestal <NUM>/<NUM> is situated between the adjacent pedestals <NUM>/<NUM> to establish a first branched section 170B-<NUM>/670B-<NUM> and a second branched section 170B-<NUM>/670B-<NUM> that join together at a merged section <NUM>/<NUM> of the cooling passage <NUM>/<NUM>.

The adjacent pedestals <NUM>/<NUM> can be dimension such that the cooling passage <NUM>/<NUM> tapers inwardly from the inlet <NUM>/<NUM>, <NUM>/<NUM> in a first direction (e.g., direction DX) towards the outlet <NUM>/<NUM> to establish respective throats <NUM>/<NUM> of the branched sections 170B-<NUM>/670B-<NUM>, 170B-<NUM>/670B-<NUM>. The pedestals <NUM>/<NUM> can be dimensioned such that the branched sections 170B/670B of the cooling passage <NUM>/<NUM> expand outwardly from the respective throats <NUM>/<NUM> in the first direction D1 towards the outlet <NUM>/<NUM> to establish respective diffusion zones <NUM>-<NUM>/<NUM>-<NUM>, <NUM>-<NUM>/<NUM>-<NUM> interconnecting the throats <NUM>-<NUM>/<NUM>-<NUM>, <NUM>-<NUM>/<NUM>-<NUM> and the outlet <NUM>/<NUM>. A casting core can be utilized in steps 1192A and 1192B to establish the cooling arrangement, such as the cores <NUM>, <NUM> of <FIG>.

At step 1192C, one or more coatings <NUM>/<NUM>, <NUM>'/<NUM>' can be formed along a surface of the wall of the component <NUM>/<NUM> and into the outlet <NUM>/<NUM> to establish a coated outlet region <NUM>/<NUM> of the respective cooling passage <NUM>/<NUM>, as illustrated by the cooling arrangement <NUM>/<NUM> of <FIG> and <FIG>. The disclosed cooling arrangements can be utilized to reduce a likelihood of metering at the coated outlet region <NUM>/<NUM> due to partial blockage. One or more finishing operations can be performed at step 1192D. Exemplary finishing operations can include machining or treating surfaces of the component, for example. Some intermittent finishing operations may also be performed between steps 1192A and 1192B, while others may be executed after step 1192B and before step 1192C.

The disclosed cooling arrangements can be utilized to provide sufficient structural support in combination with sufficient film cooling coverage to counteract high heat loads in the component during operation. The disclosed cooling arrangements can provide relatively higher film effectiveness and reduced mixing loses that may be otherwise caused by gaspath velocities being much higher than cooling flow ejected by the outlets, and can reduce variability in cooling augmentation between the adjacent cooling passages that may otherwise be caused due to variation in coating thickness. Flow separation can be reduced, including for rotating airfoils or blades which may have radial variability due to centrifugal forces caused by rotation. The throat dimensioning can be set to relatively tight tolerances which can reduce variability in cooling augmentation across the airfoils in a respective array or row, which can improve efficiency of the engine. The disclosed cooling arrangements can be utilized to provide lower material temperatures, lower thru-thickness gradients, lower transient thermal gradients, and improved durability, and may be produced at a relatively lower cost.

The disclosed cooling arrangements can be utilized to provide sufficient structural support in combination with sufficient film cooling coverage to counteract high heat loads in the component during operation. The disclosed cooling arrangements can provide relatively lower mixing losses, higher film effectiveness, lower material temperatures, lower thru-thickness gradients, lower transient thermal gradients, and improved durability, and may be produced at a relatively lower cost.

It should be understood that relative positional terms such as "forward," "aft," "upper," "lower," "above," "below," and the like are with reference to the normal operational altitude of the vehicle and should not be considered otherwise limiting.

Although the different examples have the specific components shown in the illustrations, embodiments of this invention are not limited to those particular combinations.

Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.

Claim 1:
A gas turbine engine component (<NUM>, <NUM>) comprising:
an external wall (162E) including adjacent bounding pedestals (<NUM>) that extend from an external wall surface (162SE) to establish a cooling passage (<NUM>), and including a common pedestal (<NUM>) situated between the adjacent bounding pedestals (<NUM>) to establish a first branched section (170B-<NUM>) and a second branched section (170B-<NUM>) of the cooling passage (<NUM>) that join together at a merged section (<NUM>) of the cooling passage (<NUM>), first and second inlets (<NUM>, <NUM>) established between the common pedestal (<NUM>) and respective ones of the adjacent bounding pedestals (<NUM>), the first and second inlets (<NUM>, <NUM>) coupled to an internal cavity (<NUM>), the merged section (<NUM>) interconnecting the first and second branched sections (170B-<NUM>, 170B-<NUM>) and an outlet (<NUM>), the outlet (<NUM>) established along the external wall surface (162SE) between the adjacent bounding pedestals (<NUM>) which extend to the outlet (<NUM>), and the common pedestal (<NUM>) spaced apart from the outlet (<NUM>);
wherein the adjacent bounding pedestals (<NUM>) and the common pedestal (<NUM>) are dimensioned such that first and second throats (<NUM>-<NUM>, <NUM>-<NUM>) are established along the respective first and second branched sections (170B-<NUM>, 170B-<NUM>) and such that the first and second branched sections (170B-<NUM>, 170B-<NUM>) expand towards the outlet (<NUM>) to establish respective diffusion zones (<NUM>), the diffusion zones (<NUM>) interconnecting the merged section (<NUM>) and the respective first and second throats (<NUM>-<NUM>, <NUM>-<NUM>);
one or more coatings (<NUM>) extending into the outlet (<NUM>) to establish a coated outlet region (<NUM>) of the cooling passage (<NUM>); and
wherein the first and second throats (<NUM>-<NUM>, <NUM>-<NUM>) establish a local minimum cross-sectional area (A1, A2) along the respective first and second branched sections (170B-<NUM>, 170B-<NUM>);
characterized in that a local minimum cross-sectional area (A1, A2) of the cooling passage (<NUM>) along the coated outlet region (<NUM>) divided by a total of the minimum cross-sectional areas (A1, A2) of the first and second throats (<NUM>-<NUM>, <NUM>-<NUM>) establishes a coated area ratio, and the coated area ratio is greater than or equal to <NUM>, and is less than or equal to <NUM>.