Preferential flow distribution for gas turbine engine component

A combustor liner for a gas turbine engine according to an example of the present disclosure includes, among other things, at least one liner segment that has an external wall dimensioned to bound a combustion chamber. The external wall extends between leading and trailing edges in an axial direction and extends between opposed mate faces in a circumferential direction. A cooling circuit is defined by the external wall. A plurality of heat transfer features are distributed in the cooling circuit to define a first restricted flow region that tapers from the leading edge to the trailing edge and to define at least one prioritized flow region that extends substantially from the leading edge to the trailing edge such that the at least one prioritized flow region is bounded by a perimeter of the first restricted flow region, and the at least one prioritized flow region has a lesser concentration of the plurality of heat transfer features than the first restricted flow region.

BACKGROUND

This disclosure relates to a combustor for a gas turbine engine and, more particularly, to flow distribution through a combustor liner of the combustor.

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 combustor section.

The combustor section includes one or more combustor liners that define a combustion chamber. Fuel is ejected from fuel injectors into the combustion chamber. The compressed air is mixed with the fuel and ignited in the combustion chamber to produce relatively hot combustion gases. The combustion gases expand downstream over and drive turbine blades.

The combustor liners are subject to extreme heat due to the combustion process. Formation of hot spots can occur along localized regions of the combustor liners. Cooling flow may be utilized to cool portions of the combustor liners at locations adjacent to the hot spots.

SUMMARY

A combustor liner for a gas turbine engine according to an example of the present disclosure includes at least one liner segment that has an external wall dimensioned to bound a combustion chamber. The external wall extends between leading and trailing edges in an axial direction and extends between opposed mate faces in a circumferential direction. A cooling circuit is defined by the external wall. A plurality of heat transfer features are distributed in the cooling circuit to define a first restricted flow region that tapers from the leading edge to the trailing edge and to define at least one prioritized flow region that extends substantially from the leading edge to the trailing edge such that the at least one prioritized flow region is bounded by a perimeter of the first restricted flow region, and the at least one prioritized flow region has a lesser concentration of the plurality of heat transfer features than the first restricted flow region.

In a further embodiment of any of the foregoing embodiments, the at least one prioritized flow region includes first and second prioritized flow regions on opposed sides of the first restricted flow region.

In a further embodiment of any of the foregoing embodiments, the plurality of heat transfer features are distributed in the cooling circuit to define second and third restricted flow regions that extend substantially along the mate faces to bound respective ones of the first and second prioritized flow regions.

In a further embodiment of any of the foregoing embodiments, each of the first and second prioritized flow regions has a substantially trapezoidal geometry.

In a further embodiment of any of the foregoing embodiments, the at least one liner segment includes a first liner segment and a second liner segment arranged in the axial direction to define a stepwise change in area of the combustion chamber such that the cooling circuit of the first liner segment is oriented to eject cooling flow from the trailing edge of the first liner segment onto external surfaces of the external wall of the second liner segment that defines the combustion chamber.

In a further embodiment of any of the foregoing embodiments, the at least one liner segment includes an array of liner segments, and each of the mate faces defines an intersegment gap with an adjacent one of the liner segments.

In a further embodiment of any of the foregoing embodiments, the plurality of heat transfer features includes a plurality of pedestals that extend in a radial direction between opposed internal surfaces defining the cooling circuit.

In a further embodiment of any of the foregoing embodiments, respective sets of the plurality of heat transfer features are uniformly distributed in the first restricted flow region and in the at least one prioritized flow region.

A further embodiment of any of the foregoing embodiments includes a thermal barrier coating disposed on surfaces of the external wall defining the combustion chamber.

In a further embodiment of any of the foregoing embodiments, the surfaces of the external wall defining the combustion chamber are substantially free of any cooling apertures along the cooling circuit.

In a further embodiment of any of the foregoing embodiments, the external wall is a bulkhead that bounds the combustion chamber in the axial direction. The bulkhead has at least one aperture along the combustion chamber that is dimensioned to receive a fuel injector nozzle.

A combustor section for a gas turbine engine according to an example of the present disclosure includes an array of fuel injector nozzles arranged about a longitudinal axis. A combustor liner includes an array of liner segments arranged about the longitudinal axis to define a combustion chamber. Each one of the fuel injector nozzles defines a nozzle axis. A projection of the nozzle axis extends through the combustion chamber. Each one of the liner segments includes an external wall extending axially between leading and trailing edges and extending circumferentially between opposed mate faces with respect to the longitudinal axis. A cooling circuit is defined by the external wall. A plurality of heat transfer features are distributed in the cooling circuit to define first and second prioritized flow regions on opposed sides of a first restricted flow region. Each of the first and second prioritized flow regions extend axially along the projection of the nozzle axis of respective ones of the fuel injector nozzles from the leading edge to the trailing edge such that the first restricted flow region tapers from the leading edge to the trailing edge, and each of the first and second prioritized flow regions have a relatively greater average flow path volume than the first restricted flow region.

In a further embodiment of any of the foregoing embodiments, the plurality of heat transfer features are distributed in the cooling circuit to define second and third restricted flow regions that extend substantially along the mate faces to bound a perimeter of respective ones of the first and second prioritized flow regions, and each of the first and second prioritized flow regions has a relatively greater average flow path volume than the second and third restricted flow regions.

In a further embodiment of any of the foregoing embodiments, surfaces of the external wall defining the combustion chamber are substantially free of any cooling apertures along the cooling circuit.

A gas turbine engine according to an example of the present disclosure includes a compressor section, a turbine section that drives the compressor section, a combustor section has a combustor. The combustor has a combustor liner and an array of fuel injector nozzles arranged about an engine longitudinal axis. The combustor liner has an array of liner segments arranged about the engine longitudinal axis to define a combustion chamber. Each one of the fuel injector nozzles defines a nozzle axis. A projection of the nozzle axis extends through the combustion chamber. Each one of the liner segments includes an external wall extending axially between leading and trailing edges and extending circumferentially between opposed mate faces with respect to the engine longitudinal axis. A cooling circuit is defined by the external wall. A plurality of heat transfer features are distributed in the cooling circuit to define first and second prioritized flow regions on opposed sides of a first restricted flow region. Each of the first and second prioritized flow regions extend axially along the projection of the nozzle axis of respective ones of the fuel injector nozzles such that a width of the first and second prioritized flow regions progressively increases from the leading edge to the trailing edge.

In a further embodiment of any of the foregoing embodiments, the first restricted flow region is circumferentially spaced from the projection of the nozzle axis of each and every one of the fuel injector nozzles.

In a further embodiment of any of the foregoing embodiments, the first restricted flow region tapers from the leading edge to the trailing edge.

In a further embodiment of any of the foregoing embodiments each of the mate faces defines an intersegment gap with the mate face of an adjacent one of the liner segments. The plurality of heat transfer features are distributed in the cooling circuit to define second and third restricted flow regions that extend substantially along the mate faces to bound a perimeter of respective ones of the first and second prioritized flow regions.

In a further embodiment of any of the foregoing embodiments, the intersegment gap is dimensioned to eject cooling flow into the combustion chamber.

In a further embodiment of any of the foregoing embodiments, the array of liner segments includes a first set of liner segments and a second set of liner segments axially arranged to define a stepwise change in area of the combustion chamber such that each cooling circuit of the first set of liner segments is oriented to eject cooling flow onto external surfaces of the second set of liner segments bounding the combustion chamber.

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. The drawings that accompany the detailed description can be briefly described as follows.

DETAILED DESCRIPTION

Referring toFIG. 2, the combustor56includes at least one combustor case58that extends along a longitudinal axis X. The longitudinal axis X can be parallel to or collinear with the engine longitudinal axis A ofFIG. 1. The combustor case58includes an inner (or first) combustor case58A and an outer (or second) diffuser case58B that extend about the longitudinal X. Each of the cases58A,58B has a generally annular geometry.

Referring toFIG. 3, with continuing reference toFIG. 2, a divergent nozzle or diffuser55is dimensioned to deliver flow in the core flow path C from the compressor section24(FIG. 1) to the combustor case58. The combustor56includes a plurality of combustor liners60arranged between the cases58A,58B. The combustor liners60include at least an inner (or first) combustor liner60A and an outer (or second) combustor liner60B that are concentric and are arranged to extend about the longitudinal axis X.

The inner combustion liner60A extends about the inner combustor case58A to define an inner (or first) plenum62. The outer diffuser case58B extends about the outer combustor liner60B to define an outer (or second) plenum63. Each of the plenums62,63has a generally annular geometry. The plenums62,63can be arranged to receive flow from the diffusor55.

Each combustor liner60can include one or more liner segments68. The liner segments68have an arcuate geometry and are arranged in an array about the longitudinal axis X to bound or otherwise define an annular combustion chamber64, as illustrated schematically byFIG. 3A. The liner segments68can be made of a high temperature metal or metal alloy, including directionally solidified and single crystal materials, for example.

The combustor56includes a bulkhead60C that bounds the combustion chamber64in an axial direction with respect to the longitudinal axis X. The combustor56includes an array of fuel injectors66arranged about the longitudinal axis X, as illustrated byFIGS. 3 and 3A. Each fuel injector66is fluidly coupled to a fuel source FS. The fuel source FS is operable to supply fuel to each fuel injector66during engine operation.

Each fuel injector66includes a fuel injector nozzle67that is operable to eject a quantity of fuel FF along a respective nozzle axis N. A projection of the nozzle axis N extends through the combustion chamber64. A major component of the nozzle axis N extends in a direction that is parallel to the longitudinal axis X, as illustrated byFIG. 3.

Referring toFIG. 4, with continuing reference toFIG. 3, the combustor liners60are shown with the fuel injector nozzle67ofFIG. 3removed for illustrative purposes. An injector mount65is dimensioned to receive a respective one of the nozzles67and extends along a respective nozzle axis N. The bulkhead60C can define one or more apertures61(one shown for illustrative purposes) defined along the combustion chamber64. Each aperture61is dimensioned to receive a respective fuel injector nozzle67, as illustrated byFIG. 3.

Each combustor liner60A,60B can include a liner support69that extends in the axial direction from the bulkhead60C. Each liner segment68can be mounted or otherwise mechanically attached to the liner support69with one or more fasteners73, for example.

The liner support69can have a stepwise geometry, with the liner segments68arranged in the axial direction with respect to the longitudinal axis X to define a stepwise change in area of the combustion chamber64along the liner support69. Adjacent liner segments68can axially overlap relative to the longitudinal axis X.

Each liner segment68defines a cooling circuit70that conveys cooling flow CF to cool portions of the liner segment68and adjacent portions of the combustor56, such as an adjacent (e.g., downstream) liner segment68. As illustrated byFIGS. 4 and 5, the array of liner segments68can be arranged in the axial direction with respect to longitudinal axis X to define a step formation or stepwise change in area of the combustion chamber64such that each cooling circuit70of an upstream (or first) set of liner segments68is oriented to eject cooling flow CF from a respective trailing edge68TE onto external surfaces of each external wall68A of a downstream (or second) set of liner segments68bounding the combustion chamber64, as illustrated by liner segments68-1,68-2.

FIG. 6illustrates a sectional view of one of the liner segments68defining a respective cooling circuit70. The external wall68A of the liner segment68is dimensioned to bound the combustion chamber64. The external wall68A extends between leading and trailing edges68LE,68TE in the axial direction and extends between opposing mate faces68M in a circumferential direction with respect to the longitudinal axis X. Each of the liner segments68can have a substantially rectangular cross-sectional geometry.

In examples, the external wall68A is a portion of one of the inner and/or outer combustor liners60A,60B or bulkhead60C (FIGS. 3 and 4). For example, the liner segment68can be one of the liner segments68of the inner combustion liner60A. In the illustrative example ofFIG. 6, the liner segment68is the upstream liner segment68-1of outer combustion liner60B positioned axially forward of axially aft liner segment68-2(shown in dashed lines for illustrative purposes). Liner segment68-1can be situated in a first, axially forwardmost row of the liner segments68relative to the fuel injector nozzles67and bulkhead60C, as illustrated byFIGS. 3 and 4, or can be situated in another one of the rows of liner segments68such as the second row of liner segments68-2. Although the cooling circuits disclosed herein primarily refer to a combustor, other gas turbine engine components such as walls of the core flow path C in the turbine section28or mid-turbine frame57and other systems requiring cooling augmentation can benefit from the teachings disclosed herein.

The cooling circuit70is defined by surfaces of the external wall68A. In the illustrated example ofFIG. 5, the combustion chamber64and the cooling circuit70are on opposed sides of the external wall68A. In some examples, a thermal barrier coating71is disposed on surfaces of the external wall68A (shown in dashed lines inFIG. 5for illustrated purposes). In the illustrative example ofFIGS. 5 and 6, surfaces of the external wall68A defining the combustion chamber64are substantially free of any cooling apertures along the cooling circuit70.

The liner segment68is circumferentially aligned with the nozzle axes N of two fuel injector nozzles67. The projections of the nozzle axes N can be relatively closer to the mate faces68M than arrangements having a liner segment circumferentially aligned with the nozzle axis of only one fuel injector nozzle, which may cause relatively greater thermal gradients to form across the liner segment68and non-uniform distribution of heat. The thermal gradients may cause the liner segment68to expand and distort during engine operation. The cooling circuits disclosed herein can be arranged to reduce the formation of thermal gradients across the liner segments.

Liner segment68includes a plurality of heat transfer features72extending from the external wall68A. The heat transfer features72are distributed in the cooling circuit70to interact with cooling flow CF for providing convective cooling to adjacent portions of the liner segment68. The heat transfer features72extend in a radial direction with respect to the longitudinal axis X at least partially between opposed internal surfaces of the external wall68A and liner support69that define the cooling circuit70. In the illustrative example ofFIG. 5, heat transfer features72include pin-fins or pedestals that extend in the radial direction between the opposed internal surfaces of the external wall68A and liner support69that define the cooling circuit70. Each of the pedestals can have an elliptical geometry, as illustrated byFIG. 6. However, other geometries can be utilized such as rectangular, cube, diamond, oblong, teardrop, triangular or racetrack shaped cross-sectional geometries. One would understand how to dimension the heat transfer features72utilizing the teachings disclosed herein.

The heat transfer features72are arranged in contiguous sets72-1through72-3. Each of the respective sets72-1through72-3of heat transfer features72can be uniformly distributed, as illustrated byFIG. 6. In other examples, at least some of the heat transfer features72′ in the respective sets72-1′,72-2′ and/or72-3′ are non-uniformly distributed, as illustrated byFIG. 7.

Each of the sets of heat transfer features72-1,72-2,72-3can be arranged relative to non-uniform boundary conditions such as heat concentrations or localized hotspots HS (shown in dashed lines inFIG. 6for illustrative purposes) that can form along the liner segment68during engine operation. For example, formation of localized hot spots HS can occur due to ignition of fuel FF ejected by the nozzles67. The hot spots HS can be generated or otherwise formed along the respective nozzle axes N. The hot spots HS typically have a relatively greater temperature than other portions of the liner segment68in operation, and in some scenarios can establish a peak temperature gradient relative to the liner segment68. The distribution of heat transfer features72can reduce a likelihood of degradation of the liner segment68adjacent the hot spots HS that may otherwise occur due to excessive temperature exposure and insufficient cooling augmentation.

The sets of heat transfer features72-1to72-3are distributed in the cooling circuit70to define at least one prioritized flow region and at least one restricted flow region to prioritize distribution of cooling flow CF in the cooling circuit70. In the illustrated example ofFIG. 6, the cooling circuit70includes first and second prioritized flow regions74-1,74-2that extend along and are defined on opposed sides of a first restricted flow region74-3.

The flow regions74can be dimensioned with respect to the location of each of the nozzle axes N. For example, the heat transfer features72are arranged such that the prioritized flow regions74-1,74-2extend along the projection of a respective one of the nozzle axes N, and the restricted flow region74-3is circumferentially spaced from the projection of each and every one of the nozzle axes N with respect to the longitudinal axis X.

A concentration of heat transfer features72in each flow region74can be defined with respect to a volume of the cooling circuit70per unit area, which can be set by the shape, spacing, size and/or orientation of the heat transfer features72. Each of the prioritized flow regions74-1,74-2has a relatively lesser concentration of the heat transfer features72than the restricted flow region74-3. An average concentration of heat transfer features72in the restricted flow region74-3differs in the circumferential direction from the prioritized flow regions74-1,74-2for at least a majority of axial positions relative to the longitudinal axis X.

In the illustrative example ofFIG. 6, the heat transfer features72-3in the restricted flow region74-3are more densely spaced than the heat transfer features72-1,72-2in the prioritized flow regions74-1,74-2. The relative concentrations of the heat transfer features72-1,72-2,72-3can increase the amount of convective cooling to portions of the liner segment68adjacent the localized hot spots HS, even though the concentration of heat transfer features72-1,72-2in the prioritized flow regions74-1,74-2is less than the concentration of heat transfer features72-3in the restricted flow region74-3.

The sets of heat transfer features72-1,72-2,72-3establish respective perimeters P1, P2, P3(shown in dashed lines) of the prioritized and restricted flow regions74-1,74-2,74-3. The prioritized flow regions74-1,74-2extend substantially from the leading edge68LE to the trailing edge68TE such that the perimeters P1, P2are bounded by the perimeter P3of the restricted flow region74-3. The perimeters P1, P2of the prioritized flow regions74-1,74-2extend substantially along a respective one of the mate faces68M. For the purposes of this disclosure, the term “substantially” means that the respective perimeter P1/P2/P3is defined within an average distance of the respective heat transfer features72-1/72-2/72-3from the referenced component, such as the leading edge68LE, mate faces68M and/or trailing edge68TE.

The heat transfer features72can be dimensioned and arranged such that each of the prioritized flow regions74-1,74-2has a relatively greater average flow path volume than the restricted flow region74-3. The average flow path volume can be defined as a volume of the cooling circuit70within the respective perimeter P1, P2, P3per unit area.

In examples, each of the prioritized flow regions74-1,74-2comprises at least 25% of a total flow path volume of the cooling circuit70in the liner segment68, or more narrowly between 30% and 40% of the total flow path volume, with the restricted flow region74-3comprising a remainder of the total flow path volume. In examples, the prioritized flow regions74-1,74-2have at least a quantity of three or four heat transfer features72per square inch for at least a majority of the cross sectional area of the respective prioritized flow regions74-1,74-2.

The flow regions74can be dimensioned relative to the localized hot spots HS. In the illustrative example ofFIG. 6, the perimeter P3of the restricted flow region74-3has a substantially trapezoidal (e.g., isosceles) geometry, with a width of the restricted flow region74-3generally increasing from the leading edge68LE to the trailing edge68TE. A first width W1of the restricted flow region74-3adjacent the leading edge68LE is greater than a second width W2of the restricted flow region74-3adjacent the trailing edge68TE such that at least a majority of the restricted flow region74-3progressively decreases in width or tapers from the leading edge68LE to the trailing edge68TE. The prioritized flow regions74-1,74-2are axially aligned with the restricted flow region74-3for at least a majority, or more than 75% or 90%, of a length of the liner segment68between the leading and trailing edges68LE,68TE.

The perimeters P1, P2of the prioritized flow region74-1,74-2extend between the axially forwardmost and axially aftmost heat transfer features72that are along or otherwise near the respective nozzle axes N. A width of each of the prioritized flow regions74-1,74-2can generally increase from the leading to trailing edges68LE,68TE. In the illustrated example ofFIG. 6, a third width W3of the first prioritized flow region74-1adjacent the leading edge68LE is less than a fourth width W4of the first prioritized flow region74-1adjacent the trailing edge68TE. A fifth width W5of the second prioritized flow region74-2adjacent the leading edge68LE is less than a sixth width W6of the second prioritized flow region74-2adjacent the trailing edge68TE. Widths of the respective prioritized flow regions74-1,74-2defining the perimeters P1, P2can progressively increase from the leading edge68LE to the trailing edge68TE for at least a majority of the prioritized flow regions74-1,74-2.

The difference in widths of the flow regions74relative to the leading and trailing edges68LE,68TE can increase diffusion of cooling flow CF ejected from the trailing edge68TE toward an adjacent, downstream liner segment68-2(shown in dashed lines for illustrated purposes). The heat transfer features72can be distributed such that the cooling flow CF ejected along the trailing edge68TE is diffused and substantially uniform in the circumferential direction when presented to the leading edge68LE of the downstream liner segment68-2, which can reduce a likelihood of formation of hot spots along the downstream liner segment68-2.

During operation, cooling flow CF is communicated to each of the flow regions74. The cooling flow CF can be communicated at substantially the same temperature and/or pressure to each of the flow regions74adjacent to the leading edge68LE, which serves as an inlet to the cooling circuit70. The cooling flow CF circulates across the heat transfer features72to provide convective cooling to adjacent portions of the external wall68A.

The relative concentrations of the heat transfer features72in the flow regions74can cause at least a portion of the cooling flow CF in the restricted flow region74-3to be diverted or otherwise communicated from the restricted flow region74-3to an adjacent one of the prioritized flow regions74-1,74-2due to pressure gradient(s) established by the distribution of the heat transfer features72-1,72-2,72-3, with the prioritized flow regions74-1,74-2operating at relatively lower pressures. The distribution of heat transfer features72-3establishes adverse pressure gradient(s) between the restricted flow region74-3and prioritized flow regions74-1,74-2, which opposes movement of the cooling flow CF from the prioritized flow regions74-1,74-2into the restricted flow region74-3. At least some of the cooling flow CF can circulate through the restricted flow region74-3and is then ejected from the restricted flow region74-3at the trailing edge68TE. The concentration of heat transfer features72in each of the flow regions74promotes communication of relatively more cooling flow CF in the cooling circuit70along the nozzle axes N and toward the hot spot(s) HS, which can reduce a thermal gradient across the liner segment68and improve durability of the combustor liner60(FIGS. 3 and 4).

FIG. 8illustrates a combustor liner160according to another example. 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 combustor liner160includes a plurality of liner segments168including liner segment168-1arranged circumferentially adjacent to liner segments168-2,168-3(shown in dashed lines for illustrated purposes). Liner segment168-1defines a cooling circuit170including first and second prioritized flow regions174-1,174-2that extend along opposed sides of restricted flow region174-3.

Each mate face168M of the liner segment168-1is arranged to define an intersegment gap G with the mate faces168M of adjacent liner segments168-2,168-3. As illustrated byFIG. 3A, each intersegment gap G can be dimensioned to eject cooling flow CF radially inwardly or outwardly from the intersegment gap G into the combustor chamber64to provide cooling augmentation to portions of the liner segments68adjacent the mate faces68M.

Heat transfer features172are distributed in the cooling circuit170to define second and third restricted flow regions174-4,174-5including respective sets of the heat transfer features172-4,172-5. Each of the second and third restricted flow regions174-4,174-5extends along a respective one of the mate faces168M and bounds a perimeter of a respective one of the prioritized flow regions174-1,174-2. Each of the perimeters P1, P2of the prioritized flow regions174-1,174-2has a substantially trapezoidal geometry, with a width of the prioritized flow regions174-1,174-2generally increasing from leading edge168LE to trailing edge168TE. Perimeter P3of the restricted flow region174-3has a substantially trapezoidal geometry. Perimeters P4, P5of the restricted flow regions174-4,174-5each have a substantially triangular geometry. A width of each of the restricted flow regions174-4,174-5can be set (e.g., increased or decreased) to vary the amount of cooling flow CF communicated adjacent the mate faces168M.

Each of the second and third restricted flow regions174-4,174-5has a relatively greater concentration of the heat transfer features172than an adjacent one of the prioritized flow regions174-1,174-2. The prioritized flow regions174-1,174-2have a relatively greater average flow path volume than the restricted flow regions174-3,174-4,174-5. The heat transfer features172-4,172-5in the restricted flow regions174-4,174-5can oppose or otherwise reduce the amount of cooling flow CF that is communicated from the prioritized flow regions174-1,174-2toward the intersegment gaps G, which can reduce efficiency losses that may be otherwise caused by overcooling portions of the liner segments168adjacent to the mate faces168M. The distribution of heat transfer features172-4,172-5can be the same or can differ from the distribution of heat transfer features172-3, including shape, spacing and/or orientation. In the illustrated example ofFIG. 8, an average size of the heat transfer features172-4,172-5is less than an average size of the heat transfer features172-3, and an average spacing between the heat transfer features172-4,172-5is greater than an average spacing between the heat transfer features172-3.

FIG. 9illustrates a liner segment268defining a cooling circuit270according to yet another example. Heat transfer features272-1,272-4,272-5are arranged to define restricted flow regions274-4,274-5that extend along mate faces268M and along opposed sides of prioritized flow region274-1. Heat transfer features272-1have a relatively greater diameter and are less densely spaced than heat transfer features274-4,274-5such that the prioritized flow region274-1has a relatively greater average flow path volume than the restricted flow regions274-4,274-5to promote flow of cooling flow CF toward and along a projection of nozzle axis N. In the illustrated example ofFIG. 10, heat transfer features372-1have a substantially rectangular geometry, with a major component of a length of the heat transfer features372-1oriented in a circumferential direction with respect to a respective nozzle axis N and/or longitudinal axis X to oppose cooling flow CF.

FIG. 11illustrates example geometries of heat transfer features472that can be utilized in any of the cooling circuits disclosed herein. Heat transfer features472A have a substantially cylindrical cross-sectional geometry. Heat transfer features472B have an elliptical, non-circular geometry. Heat transfer features472C have an elongated, substantially rectangular geometry. Heat transfer features472D have a diamond shaped geometry. Heat transfer features472E have a race track shaped geometry. Heat transfer features472F have a teardrop shaped geometry. The arrangement of heat transfer features472B,472C can improve diffusion of cooling flow CF outwardly from trailing edge468TE of liner segment468and reduce distress by orienting the cooling flow CF toward a localized hot spot of a downstream liner segment.