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 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.

<CIT> discloses wall elements for gas turbine engine combustors.

<CIT> discloses a combustor section according to the prior art.

The present application provides a combustor section for a gas turbine engine as set forth in claim <NUM>.

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.

"Low corrected fan tip speed" is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram °R) / (<NUM> °R)]<NUM> (where °R = K × <NUM>/<NUM>).

Referring to <FIG>, the combustor <NUM> includes at least one combustor case <NUM> that extends along a longitudinal axis X. The longitudinal axis X can be parallel to or collinear with the engine longitudinal axis A of <FIG>. The combustor case <NUM> includes an inner (or first) combustor case 58A and an outer (or second) diffuser case 58B that extend about the longitudinal X. Each of the cases 58A, 58B has a generally annular geometry.

Referring to <FIG>, with continuing reference to <FIG>, a divergent nozzle or diffuser <NUM> is dimensioned to deliver flow in the core flow path C from the compressor section <NUM> (<FIG>) to the combustor case <NUM>. The combustor <NUM> includes a plurality of combustor liners <NUM> arranged between the cases 58A, 58B. The combustor liners <NUM> include at least an inner (or first) combustor liner 60A and an outer (or second) combustor liner 60B that are concentric and are arranged to extend about the longitudinal axis X.

The inner combustion liner 60A extends about the inner combustor case 58A to define an inner (or first) plenum <NUM>. The outer diffuser case 58B extends about the outer combustor liner 60B to define an outer (or second) plenum <NUM>. Each of the plenums <NUM>, <NUM> has a generally annular geometry. The plenums <NUM>, <NUM> can be arranged to receive flow from the diffusor <NUM>.

Each combustor liner <NUM> can include one or more liner segments <NUM>. The liner segments <NUM> have an arcuate geometry and are arranged in an array about the longitudinal axis X to bound or otherwise define an annular combustion chamber <NUM>, as illustrated schematically by <FIG>. The liner segments <NUM> can be made of a high temperature metal or metal alloy, including directionally solidified and single crystal materials, for example.

The combustor <NUM> includes a bulkhead 60C that bounds the combustion chamber <NUM> in an axial direction with respect to the longitudinal axis X. The combustor <NUM> includes an array of fuel injectors <NUM> arranged about the longitudinal axis X, as illustrated by <FIG>. Each fuel injector <NUM> is fluidly coupled to a fuel source FS. The fuel source FS is operable to supply fuel to each fuel injector <NUM> during engine operation.

Each fuel injector <NUM> includes a fuel injector nozzle <NUM> that 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 chamber <NUM>. A major component of the nozzle axis N extends in a direction that is parallel to the longitudinal axis X, as illustrated by <FIG>.

Referring to <FIG>, with continuing reference to <FIG>, the combustor liners <NUM> are shown with the fuel injector nozzle <NUM> of <FIG> removed for illustrative purposes. An injector mount <NUM> is dimensioned to receive a respective one of the nozzles <NUM> and extends along a respective nozzle axis N. The bulkhead 60C can define one or more apertures <NUM> (one shown for illustrative purposes) defined along the combustion chamber <NUM>. Each aperture <NUM> is dimensioned to receive a respective fuel injector nozzle <NUM>, as illustrated by <FIG>.

Each combustor liner 60A, 60B can include a liner support <NUM> that extends in the axial direction from the bulkhead 60C. Each liner segment <NUM> can be mounted or otherwise mechanically attached to the liner support <NUM> with one or more fasteners <NUM>, for example.

The liner support <NUM> can have a stepwise geometry, with the liner segments <NUM> arranged in the axial direction with respect to the longitudinal axis X to define a stepwise change in area of the combustion chamber <NUM> along the liner support <NUM>. Adjacent liner segments <NUM> can axially overlap relative to the longitudinal axis X.

Each liner segment <NUM> defines a cooling circuit <NUM> that conveys cooling flow CF to cool portions of the liner segment <NUM> and adjacent portions of the combustor <NUM>, such as an adjacent (e.g., downstream) liner segment <NUM>. As illustrated by <FIG> and <FIG>, the array of liner segments <NUM> can 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 chamber <NUM> such that each cooling circuit <NUM> of an upstream (or first) set of liner segments <NUM> is oriented to eject cooling flow CF from a respective trailing edge 68TE onto external surfaces of each external wall 68A of a downstream (or second) set of liner segments <NUM> bounding the combustion chamber <NUM>, as illustrated by liner segments <NUM>-<NUM>, <NUM>-<NUM>.

<FIG> illustrates a sectional view of one of the liner segments <NUM> defining a respective cooling circuit <NUM>. The external wall 68A of the liner segment <NUM> is dimensioned to bound the combustion chamber <NUM>. The external wall 68A extends between leading and trailing edges 68LE, 68TE in the axial direction and extends between opposing mate faces <NUM> in a circumferential direction with respect to the longitudinal axis X. Each of the liner segments <NUM> can have a substantially rectangular cross-sectional geometry.

In examples, the external wall 68A is a portion of one of the inner and/or outer combustor liners 60A, 60B or bulkhead 60C (<FIG> and <FIG>). For example, the liner segment <NUM> can be one of the liner segments <NUM> of the inner combustion liner 60A. In the illustrative example of <FIG>, the liner segment <NUM> is the upstream liner segment <NUM>-<NUM> of outer combustion liner 60B positioned axially forward of axially aft liner segment <NUM>-<NUM> (shown in dashed lines for illustrative purposes). Liner segment <NUM>-<NUM> can be situated in a first, axially forwardmost row of the liner segments <NUM> relative to the fuel injector nozzles <NUM> and bulkhead 60C, as illustrated by <FIG> and <FIG>, or can be situated in another one of the rows of liner segments <NUM> such as the second row of liner segments <NUM>-<NUM>. 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 section <NUM> or mid-turbine frame <NUM> and other systems requiring cooling augmentation can benefit from the teachings disclosed herein.

The cooling circuit <NUM> is defined by surfaces of the external wall 68A. In the illustrated example of <FIG>, the combustion chamber <NUM> and the cooling circuit <NUM> are on opposed sides of the external wall 68A. In some examples, a thermal barrier coating <NUM> is disposed on surfaces of the external wall 68A (shown in dashed lines in <FIG> for illustrated purposes). In the illustrative example of <FIG>, surfaces of the external wall 68A defining the combustion chamber <NUM> are substantially free of any cooling apertures along the cooling circuit <NUM>.

The liner segment <NUM> is circumferentially aligned with the nozzle axes N of two fuel injector nozzles <NUM>. The projections of the nozzle axes N can be relatively closer to the mate faces <NUM> 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 segment <NUM> and non-uniform distribution of heat. The thermal gradients may cause the liner segment <NUM> to 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 segment <NUM> includes a plurality of heat transfer features <NUM> extending from the external wall 68A. The heat transfer features <NUM> are distributed in the cooling circuit <NUM> to interact with cooling flow CF for providing convective cooling to adjacent portions of the liner segment <NUM>. The heat transfer features <NUM> extend in a radial direction with respect to the longitudinal axis X at least partially between opposed internal surfaces of the external wall 68A and liner support <NUM> that define the cooling circuit <NUM>. In the illustrative example of <FIG>, heat transfer features <NUM> include pin-fins or pedestals that extend in the radial direction between the opposed internal surfaces of the external wall 68A and liner support <NUM> that define the cooling circuit <NUM>. Each of the pedestals can have an elliptical geometry, as illustrated by <FIG>. 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 features <NUM> utilizing the teachings disclosed herein.

The heat transfer features <NUM> are arranged in contiguous sets <NUM>-<NUM> through <NUM>-<NUM>. Each of the respective sets <NUM>-<NUM> through <NUM>-<NUM> of heat transfer features <NUM> can be uniformly distributed, as illustrated by <FIG>. In other examples, at least some of the heat transfer features <NUM>' in the respective sets <NUM>-<NUM>', <NUM>-<NUM>' and/or <NUM>-<NUM>' are non-uniformly distributed, as illustrated by <FIG>.

Each of the sets of heat transfer features <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> can be arranged relative to non-uniform boundary conditions such as heat concentrations or localized hotspots HS (shown in dashed lines in <FIG> for illustrative purposes) that can form along the liner segment <NUM> during engine operation. For example, formation of localized hot spots HS can occur due to ignition of fuel FF ejected by the nozzles <NUM>. 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 segment <NUM> in operation, and in some scenarios can establish a peak temperature gradient relative to the liner segment <NUM>. The distribution of heat transfer features <NUM> can reduce a likelihood of degradation of the liner segment <NUM> adjacent the hot spots HS that may otherwise occur due to excessive temperature exposure and insufficient cooling augmentation.

The sets of heat transfer features <NUM>-<NUM> to <NUM>-<NUM> are distributed in the cooling circuit <NUM> to define at least one prioritized flow region and at least one restricted flow region to prioritize distribution of cooling flow CF in the cooling circuit <NUM>. In the illustrated example of <FIG>, the cooling circuit <NUM> includes first and second prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> that extend along and are defined on opposed sides of a first restricted flow region <NUM>-<NUM>.

The flow regions <NUM> can be dimensioned with respect to the location of each of the nozzle axes N. For example, the heat transfer features <NUM> are arranged such that the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> extend along the projection of a respective one of the nozzle axes N, and the restricted flow region <NUM>-<NUM> is 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 features <NUM> in each flow region <NUM> can be defined with respect to a volume of the cooling circuit <NUM> per unit area, which can be set by the shape, spacing, size and/or orientation of the heat transfer features <NUM>. Each of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> has a relatively lesser concentration of the heat transfer features <NUM> than the restricted flow region <NUM>-<NUM>. An average concentration of heat transfer features <NUM> in the restricted flow region <NUM>-<NUM> differs in the circumferential direction from the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> for at least a majority of axial positions relative to the longitudinal axis X.

In the illustrative example of <FIG>, the heat transfer features <NUM>-<NUM> in the restricted flow region <NUM>-<NUM> are more densely spaced than the heat transfer features <NUM>-<NUM>, <NUM>-<NUM> in the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM>. The relative concentrations of the heat transfer features <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> can increase the amount of convective cooling to portions of the liner segment <NUM> adjacent the localized hot spots HS, even though the concentration of heat transfer features <NUM>-<NUM>, <NUM>-<NUM> in the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> is less than the concentration of heat transfer features <NUM>-<NUM> in the restricted flow region <NUM>-<NUM>.

The sets of heat transfer features <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> establish respective perimeters P1, P2, P3 (shown in dashed lines) of the prioritized and restricted flow regions <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>. The prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> extend substantially from the leading edge 68LE to the trailing edge 68TE such that the perimeters P1, P2 are bounded by the perimeter P3 of the restricted flow region <NUM>-<NUM>. The perimeters P1, P2 of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> extend substantially along a respective one of the mate faces <NUM>. For the purposes of this disclosure, the term "substantially" means that the respective perimeter P1/P2/P3 is defined within an average distance of the respective heat transfer features <NUM>-<NUM>/<NUM>-<NUM>/<NUM>-<NUM> from the referenced component, such as the leading edge 68LE, mate faces <NUM> and/or trailing edge 68TE.

The heat transfer features <NUM> can be dimensioned and arranged such that each of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> has a relatively greater average flow path volume than the restricted flow region <NUM>-<NUM>. The average flow path volume can be defined as a volume of the cooling circuit <NUM> within the respective perimeter P1, P2, P3 per unit area.

In examples, each of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> comprises at least <NUM>% of a total flow path volume of the cooling circuit <NUM> in the liner segment <NUM>, or more narrowly between <NUM>% and <NUM>% of the total flow path volume, with the restricted flow region <NUM>-<NUM> comprising a remainder of the total flow path volume. In examples, the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> have at least a quantity of three or four heat transfer features <NUM> per square inch for at least a majority of the cross sectional area of the respective prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM>.

The flow regions <NUM> can be dimensioned relative to the localized hot spots HS. In the illustrative example of <FIG>, the perimeter P3 of the restricted flow region <NUM>-<NUM> has a substantially trapezoidal (e.g., isosceles) geometry, with a width of the restricted flow region <NUM>-<NUM> generally increasing from the leading edge 68LE to the trailing edge 68TE. A first width W1 of the restricted flow region <NUM>-<NUM> adjacent the leading edge 68LE is greater than a second width W2 of the restricted flow region <NUM>-<NUM> adjacent the trailing edge 68TE such that at least a majority of the restricted flow region <NUM>-<NUM> progressively decreases in width or tapers from the leading edge 68LE to the trailing edge 68TE. The prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> are axially aligned with the restricted flow region <NUM>-<NUM> for at least a majority, or more than <NUM>% or <NUM>%, of a length of the liner segment <NUM> between the leading and trailing edges 68LE, 68TE.

The perimeters P1, P2 of the prioritized flow region <NUM>-<NUM>, <NUM>-<NUM> extend between the axially forwardmost and axially aftmost heat transfer features <NUM> that are along or otherwise near the respective nozzle axes N. A width of each of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> can generally increase from the leading to trailing edges 68LE, 68TE. In the illustrated example of <FIG>, a third width W3 of the first prioritized flow region <NUM>-<NUM> adjacent the leading edge 68LE is less than a fourth width W4 of the first prioritized flow region <NUM>-<NUM> adjacent the trailing edge 68TE. A fifth width W5 of the second prioritized flow region <NUM>-<NUM> adjacent the leading edge 68LE is less than a sixth width W6 of the second prioritized flow region <NUM>-<NUM> adjacent the trailing edge 68TE. Widths of the respective prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> defining the perimeters P1, P2 can progressively increase from the leading edge 68LE to the trailing edge 68TE for at least a majority of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM>.

The difference in widths of the flow regions <NUM> relative to the leading and trailing edges 68LE, 68TE can increase diffusion of cooling flow CF ejected from the trailing edge 68TE toward an adjacent, downstream liner segment <NUM>-<NUM> (shown in dashed lines for illustrated purposes). The heat transfer features <NUM> can be distributed such that the cooling flow CF ejected along the trailing edge 68TE is diffused and substantially uniform in the circumferential direction when presented to the leading edge 68LE of the downstream liner segment <NUM>-<NUM>, which can reduce a likelihood of formation of hot spots along the downstream liner segment <NUM>-<NUM>.

During operation, cooling flow CF is communicated to each of the flow regions <NUM>. The cooling flow CF can be communicated at substantially the same temperature and/or pressure to each of the flow regions <NUM> adjacent to the leading edge 68LE, which serves as an inlet to the cooling circuit <NUM>. The cooling flow CF circulates across the heat transfer features <NUM> to provide convective cooling to adjacent portions of the external wall 68A.

The relative concentrations of the heat transfer features <NUM> in the flow regions <NUM> can cause at least a portion of the cooling flow CF in the restricted flow region <NUM>-<NUM> to be diverted or otherwise communicated from the restricted flow region <NUM>-<NUM> to an adjacent one of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> due to pressure gradient(s) established by the distribution of the heat transfer features <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, with the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> operating at relatively lower pressures. The distribution of heat transfer features <NUM>-<NUM> establishes adverse pressure gradient(s) between the restricted flow region <NUM>-<NUM> and prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM>, which opposes movement of the cooling flow CF from the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> into the restricted flow region <NUM>-<NUM>. At least some of the cooling flow CF can circulate through the restricted flow region <NUM>-<NUM> and is then ejected from the restricted flow region <NUM>-<NUM> at the trailing edge 68TE. The concentration of heat transfer features <NUM> in each of the flow regions <NUM> promotes communication of relatively more cooling flow CF in the cooling circuit <NUM> along the nozzle axes N and toward the hot spot(s) HS, which can reduce a thermal gradient across the liner segment <NUM> and improve durability of the combustor liner <NUM> (<FIG> and <FIG>).

<FIG> illustrates a combustor liner <NUM> according 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 liner <NUM> includes a plurality of liner segments <NUM> including liner segment <NUM>-<NUM> arranged circumferentially adjacent to liner segments <NUM>-<NUM>, <NUM>-<NUM> (shown in dashed lines for illustrated purposes). Liner segment <NUM>-<NUM> defines a cooling circuit <NUM> including first and second prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> that extend along opposed sides of restricted flow region <NUM>-<NUM>.

Each mate face <NUM> of the liner segment <NUM>-<NUM> is arranged to define an intersegment gap G with the mate faces <NUM> of adjacent liner segments <NUM>-<NUM>, <NUM>-<NUM>. As illustrated by <FIG>, each intersegment gap G can be dimensioned to eject cooling flow CF radially inwardly or outwardly from the intersegment gap G into the combustor chamber <NUM> to provide cooling augmentation to portions of the liner segments <NUM> adjacent the mate faces <NUM>.

Heat transfer features <NUM> are distributed in the cooling circuit <NUM> to define second and third restricted flow regions <NUM>-<NUM>, <NUM>-<NUM> including respective sets of the heat transfer features <NUM>-<NUM>, <NUM>-<NUM>. Each of the second and third restricted flow regions <NUM>-<NUM>, <NUM>-<NUM> extends along a respective one of the mate faces <NUM> and bounds a perimeter of a respective one of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM>. Each of the perimeters P1, P2 of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> has a substantially trapezoidal geometry, with a width of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> generally increasing from leading edge 168LE to trailing edge 168TE. Perimeter P3 of the restricted flow region <NUM>-<NUM> has a substantially trapezoidal geometry. Perimeters P4, P5 of the restricted flow regions <NUM>-<NUM>, <NUM>-<NUM> each have a substantially triangular geometry. A width of each of the restricted flow regions <NUM>-<NUM>, <NUM>-<NUM> can be set (e.g., increased or decreased) to vary the amount of cooling flow CF communicated adjacent the mate faces <NUM>.

Each of the second and third restricted flow regions <NUM>-<NUM>, <NUM>-<NUM> has a relatively greater concentration of the heat transfer features <NUM> than an adjacent one of the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM>. The prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> have a relatively greater average flow path volume than the restricted flow regions <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>. The heat transfer features <NUM>-<NUM>, <NUM>-<NUM> in the restricted flow regions <NUM>-<NUM>, <NUM>-<NUM> can oppose or otherwise reduce the amount of cooling flow CF that is communicated from the prioritized flow regions <NUM>-<NUM>, <NUM>-<NUM> toward the intersegment gaps G, which can reduce efficiency losses that may be otherwise caused by overcooling portions of the liner segments <NUM> adjacent to the mate faces <NUM>. The distribution of heat transfer features <NUM>-<NUM>, <NUM>-<NUM> can be the same or can differ from the distribution of heat transfer features <NUM>-<NUM>, including shape, spacing and/or orientation. In the illustrated example of <FIG>, an average size of the heat transfer features <NUM>-<NUM>, <NUM>-<NUM> is less than an average size of the heat transfer features <NUM>-<NUM>, and an average spacing between the heat transfer features <NUM>-<NUM>, <NUM>-<NUM> is greater than an average spacing between the heat transfer features <NUM>-<NUM>.

<FIG> illustrates a liner segment <NUM> defining a cooling circuit <NUM> according to yet another example. Heat transfer features <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> are arranged to define restricted flow regions <NUM>-<NUM>, <NUM>-<NUM> that extend along mate faces <NUM> and along opposed sides of prioritized flow region <NUM>-<NUM>. Heat transfer features <NUM>-<NUM> have a relatively greater diameter and are less densely spaced than heat transfer features <NUM>-<NUM>, <NUM>-<NUM> such that the prioritized flow region <NUM>-<NUM> has a relatively greater average flow path volume than the restricted flow regions <NUM>-<NUM>, <NUM>-<NUM> to promote flow of cooling flow CF toward and along a projection of nozzle axis N. In the illustrated example of <FIG>, heat transfer features <NUM>-<NUM> have a substantially rectangular geometry, with a major component of a length of the heat transfer features <NUM>-<NUM> oriented in a circumferential direction with respect to a respective nozzle axis N and/or longitudinal axis X to oppose cooling flow CF.

<FIG> illustrates example geometries of heat transfer features <NUM> that can be utilized in any of the cooling circuits disclosed herein. Heat transfer features 472A have a substantially cylindrical cross-sectional geometry. Heat transfer features 472B have an elliptical, non-circular geometry. Heat transfer features 472C have an elongated, substantially rectangular geometry. Heat transfer features 472D have a diamond shaped geometry. Heat transfer features 472E have a race track shaped geometry. Heat transfer features 472F have a teardrop shaped geometry. The arrangement of heat transfer features 472B, 472C can improve diffusion of cooling flow CF outwardly from trailing edge 468TE of liner segment <NUM> and reduce distress by orienting the cooling flow CF toward a localized hot spot of a downstream liner segment.

Claim 1:
A combustor section (<NUM>) for a gas turbine engine (<NUM>) comprising:
an array of fuel injector nozzles (<NUM>) arranged about a longitudinal axis (A);
a combustor liner (<NUM>) including an array of liner segments (<NUM>; <NUM>) arranged about the longitudinal axis (A) to define a combustion chamber (<NUM>), wherein each one of the fuel injector nozzles (<NUM>) defines a nozzle axis (N), a projection of the nozzle axis (N) extending through the combustion chamber (<NUM>), and each one of the liner segments (<NUM>; <NUM>) comprises an external wall (68A) extending axially between leading and trailing edges (68LE, 68TE; 168LE, 168TE) and extending circumferentially between opposed mate faces (<NUM>; <NUM>) with respect to the longitudinal axis (A), wherein a cooling circuit (<NUM>; <NUM>) is defined by the external wall (68A), and a plurality of heat transfer features (<NUM>; <NUM>) are distributed in the cooling circuit (<NUM>; <NUM>) to define first and second prioritized flow regions (<NUM>-<NUM>, <NUM>-<NUM>; <NUM>-<NUM>, <NUM>-<NUM>) on opposed sides of a first restricted flow region (<NUM>-<NUM>; <NUM>-<NUM>), each of the first and second prioritized flow regions (<NUM>-<NUM>, <NUM>-<NUM>; <NUM>-<NUM>, <NUM>-<NUM>) extending axially along the projection of the nozzle axis (N) of respective ones of the fuel injector nozzles (<NUM>) from the leading edge (68LE; 168LE) to the trailing edge (68TE; 168TE) such that the first restricted flow region (<NUM>-<NUM>; <NUM>-<NUM>) tapers from the leading edge (68LE; 168LE) to the trailing edge (68TE; 168TE), each of the first and second prioritized flow regions (<NUM>-<NUM>, <NUM>-<NUM>; <NUM>-<NUM>, <NUM>-<NUM>) having a relatively greater average flow path volume than the first restricted flow region (<NUM>-<NUM>; <NUM>-<NUM>), and wherein the first and second prioritized flow regions (<NUM>-<NUM>, <NUM>-<NUM>; <NUM>-<NUM>, <NUM>-<NUM>) has a lesser concentration of the plurality of heat transfer features (<NUM>; <NUM>) than the first restricted flow region (<NUM>-<NUM>; <NUM>-<NUM>).