1. Technical Field
This disclosure relates generally to a turbine engine combustor and, more particularly, to a turbine engine combustor wall with a non-uniform distribution of effusion apertures.
2. Background Information
A turbine engine typically includes a fan, a compressor, a combustor, and a turbine. The combustor typically includes an annular bulkhead extending radially between an upstream end of a radial inner combustor wall and an upstream end of a radial outer combustor wall. The inner and the outer combustor walls can each include an impingement cavity extending radially between a support shell and a heat shield. The support shell can include a plurality of impingement apertures, which directs cooling air from a plenum surrounding the combustor into the impingement cavity and against an impingement cavity surface of the heat shield. The heat shield can include a plurality of effusion apertures, which directs the cooling air from the impingement cavity into the combustion chamber for film cooling a combustion chamber surface of the heat shield.
During operation, fuel provided by a plurality of combustor fuel injectors is mixed with compressed gas within the combustion chamber, and the mixture is ignited. Due to varying flow and combustion temperatures within the combustion chamber, the inner and outer combustor walls can be subject to axially and circumferentially varying combustion chamber gas temperatures. Such varying temperatures can cause significant temperature differentials with combustor walls, which can cause combustor wall material fatigue, etc.
According to a first aspect of the invention, a combustor wall is provided for a turbine engine with an axial centerline. The combustor wall includes a combustor support shell and a combustor heat shield. The support shell includes a plurality of shell quench apertures, a plurality of first impingement apertures, and a plurality of second impingement apertures. The heat shield includes a plurality of shield quench apertures fluidly coupled with the shell quench apertures, a plurality of first effusion apertures fluidly coupled with the first impingement apertures, and a plurality of second effusion apertures fluidly coupled with the second impingement apertures. The shield quench apertures and the first effusion apertures are configured in a first axial region of the heat shield. The second effusion apertures are configured in a second axial region of the heat shield located axially between the first axial region and a downstream end of the heat shield. A density of the first effusion apertures in the first axial region is greater than a density of the second effusion apertures in the second axial region.
According to a second aspect of the invention, an axial flow combustor is provided for a turbine engine with an axial centerline. The combustor includes a first combustor wall, a second combustor wall with a support shell and a heat shield, and an annular combustor bulkhead extending radially between an upstream end of the first combustor wall and an upstream end of the second combustor wall. The support shell includes a plurality of shell quench apertures, a plurality of first impingement apertures, and a plurality of second impingement apertures. The heat shield includes a plurality of shield quench apertures fluidly coupled with the shell quench apertures, a plurality of first effusion apertures fluidly coupled with the first impingement apertures, and a plurality of second effusion apertures fluidly coupled with the second impingement apertures. The shield quench apertures and the first effusion apertures are configured in a first axial region of the heat shield. The second effusion apertures are configured in a second axial region of the heat shield. The first axial region is located axially between the upstream end of the second combustor wall and the second axial region. A density of the first effusion apertures in the first axial region is greater than a density of the second effusion apertures in the second axial region. The first combustor wall may be disposed radially within the second combustor wall. Alternatively, the second combustor wall may be disposed radially within the first combustor wall.
In some embodiments, the support shell also includes a plurality of third impingement apertures, and the heat shield also includes a plurality of third effusion apertures, which are fluidly coupled with the third impingement apertures. The third effusion apertures are configured in a third axial region of the heat shield located axially between the first axial region and an upstream end of the heat shield. A density of the third effusion apertures in the third axial region is less than the density of the first effusion apertures in the first axial region.
In some embodiments, the density of the third effusion apertures in the third axial region is greater than the density of the second effusion apertures in the second axial region.
In some embodiments, the support shell also includes a plurality of third impingement apertures, and the heat shield also includes a plurality of third effusion apertures, which are fluidly coupled with the third impingement apertures. Axes of more than seventy five percent of the third effusion apertures extend circumferentially through the panel and are substantially perpendicular to the axial centerline. The third effusion apertures are configured in a third axial region of the heat shield located axially between the first axial region and an upstream end of the heat shield. A density of the third effusion apertures in the third axial region may be substantially equal to the density of the first effusion apertures in the first axial region.
In some embodiments, a plurality of the first effusion apertures, located adjacent to a first of the panel quench apertures, have axes that are substantially tangent to a downstream side of the first panel quench aperture.
In some embodiments, the impingement apertures are configured to exhibit a pressure drop across the support shell, and the effusion apertures are configured to exhibit a pressure drop across the heat shield. A ratio of the pressure drop across the support shell to the pressure drop across the heat shield can be between about 2:1 and about 9:1.
In some embodiments, some or all of the impingement apertures and some or all of the effusion apertures have substantially equal diameters. In other embodiments, the diameters of some or all of the effusion apertures are greater than diameters of some or all of the impingement apertures. In still other embodiments, the diameters of some or all of the effusion apertures are less than diameters of some or all of the impingement apertures.
In some embodiments, axes of some or all of the effusion apertures are offset from a combustion chamber surface of the heat shield by between about fifteen and about thirty degrees, and/or axes of some or all of the impingement apertures are substantially perpendicular to an impingement cavity surface of the support shell.
In some embodiments, an impingement cavity extends radially between the support shell and the heat shield, and fluidly couples some or all of the impingement apertures with some or all of the effusion apertures. The support shell has an annular cross-sectional geometry and extends axially between an upstream end and a downstream end. The heat shield has an annular cross-sectional geometry and extends axially between an upstream end and the downstream end of the panel.
In some embodiments, the heat shield is disposed radially within the support shell. In other embodiments, the support shell is disposed radially within the heat shield.
In some embodiments, the heat shield includes a plurality of circumferential heat shield panels and/or a plurality of axial heat shield panels.
In some embodiments, the first axial region and/or the second axial region includes a plurality of circumferential first sub-regions and a plurality of circumferential second sub-regions. A density of the effusion apertures in each first sub-region is greater than a density of the effusion apertures in each second sub-region. The density of the effusion apertures in the respective axial region is equal to an average or mean of the densities of the effusion apertures in the first sub-regions and the densities of the effusion apertures in the second sub-regions.
In some embodiments, the shell quench apertures and the first impingement apertures are configured in a first axial region of the support shell, and the second impingement apertures are configured in a second axial region of the support shell located axially between the first axial region of the support shell and a downstream end of the support shell. A density of the first impingement apertures in the first axial region of the support shell is greater than a density of the second impingement apertures in the second axial region of the support shell.
The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings.
The first combustor wall 16 and the second combustor wall 20 can each include a combustor support shell 30 and a combustor heat shield 32. The support shell 30 extends axially between the upstream end 14, 18 and a downstream end 34, 36. The support shell 30 extends circumferentially around the axial centerline 24, which provides the support shell 30 with an annular cross-sectional geometry. Referring to
Referring to
The impingement apertures (e.g., the apertures 44) extend radially through the support shell 30 between the combustor plenum surface 38 and the first impingement cavity surface 40. Each of the impingement apertures (e.g., the apertures 44) has an axis 48 that is angularly offset from first impingement cavity surface 40, for example, by an angle θ of about ninety degrees. Each of the impingement apertures (e.g., the apertures 44) can have a circular cross-sectional geometry with a second diameter 50, which is substantially (e.g., at least five to twenty times) smaller than the first diameter 46. Referring to
The shell quench apertures 42 and the impingement apertures can be arranged in one or more support shell cooling regions. The first impingement apertures 52, for example, are arranged in a first axial region 62. The first axial region 62 extends axially from a second axial region 64 towards the upstream end 14, 18, and circumferentially around the centerline 24. The second impingement apertures 54 are arranged in the second axial region 64. The second axial region 64 extends axially from the first axial region 62 to a third axial region 66, and circumferentially around the centerline 24. The third impingement apertures 56 are arranged in the third axial region 66. The third axial region 66 extends axially from the second axial region 64 to a fourth axial region 68, and circumferentially around the centerline 24. The shell quench apertures 42 and the fourth impingement apertures 44 are arranged in the fourth axial region 68. The fourth axial region 68 extends axially from the third axial region 65 to a fifth axial region 70, and circumferentially around the centerline 24. The fifth impingement apertures 58 are arranged in the fifth axial region 70. The fifth axial region 70 extends axially from the fourth axial region 68 to a sixth axial region 72, and circumferentially around the centerline 24. The sixth impingement apertures 60 are arranged in the sixth axial region 72. The sixth axial region 72 extends axially from the fifth axial region 70 towards (e.g., to) the downstream end 34, 36, and circumferentially around the centerline 24.
The number of and relative spacing between the impingement apertures included in each of the support shell cooling regions is selected to provide each cooling region with a respective impingement aperture density. The term “impingement aperture density” describes a ratio of the number of impingement apertures included in a unit (e.g., a square inch) of substantially unobstructed support shell surface area. Unobstructed support shell surface area can include, for example, portions of the first impingement cavity surface 40 that do not include non-cooling apertures (e.g., the shell quench apertures 42) and/or other support shell features such as, for example, bosses, studs, flanges, rails, etc. connected to the combustor plenum surface 38. Obstructed support shell surfaces can include, for example, first regions 74 of the first impingement cavity surface opposite shell quench aperture 42 rails, and second regions 76 of the first impingement cavity surface opposite stud apertures.
In the specific embodiment of
In some embodiments, the impingement aperture density in one or more of the support shell cooling regions may change (e.g., intermittently increase and decrease) as the region extends circumferentially around the centerline 24. In the specific embodiment of
Referring again to
Referring to
The effusion apertures (e.g., the apertures 96) extend radially through the heat shield 32 between the second impingement cavity surface 86 and the combustion chamber surface 88. Each of the effusion apertures (e.g., the apertures 96) has an axis 100 that is angularly offset from the combustion chamber surface 88, for example, by an angle α of between about fifteen and about thirty degrees (e.g., about 25°). Each of the effusion apertures (e.g., the apertures 96) can have a circular cross-sectional geometry with a fourth diameter 102, which is substantially (e.g., at least five to twenty times) smaller than the third diameter 98. The fourth diameter 102 of some or all of the effusion apertures can be greater than, less than or equal to the second diameter 50. Referring to
The shield quench apertures 94 and the effusion apertures can be arranged in one or more heat shield cooling regions. The first effusion apertures 104, for example, are arranged in a first axial region 114. The first axial region 114 extends axially from a second axial region 116 towards (e.g., to) the upstream end 82, and circumferentially around the centerline 24. The second effusion apertures 106 are arranged in the second axial region 116. The second axial region 116 extends axially from the first axial region 114 to a third axial region 118, and circumferentially around the centerline 24. The third effusion apertures 108 are arranged in the third axial region 118. The third axial region 118 extends axially from the second axial region 116 to a fourth axial region 120, and circumferentially around the centerline 24. The shield quench apertures 94 and the fourth effusion apertures 96 are arranged in the fourth axial region 120. The fourth axial region 120 extends axially from the third axial region 118 to a fifth axial region 122, and circumferentially around the centerline 24. The fifth effusion apertures 110 are arranged in the fifth axial region 122. The fifth axial region 122 extends axially from the fourth axial region 120 to a sixth axial region 124, and circumferentially around the centerline 24. The sixth effusion apertures 112 are arranged in the sixth axial region 124. The sixth axial region 124 extends axially from the fifth axial region 122 towards (e.g., to) the downstream end 84, and circumferentially around the centerline 24.
The number of and relative spacing between the effusion apertures included in each of the heat shield cooling regions is selected to provide each cooling region with a respective effusion aperture density. The term “effusion aperture density” describes a ratio of the number of effusion apertures included in a unit (e.g., a square inch) of substantially unobstructed heat shield surface area. Unobstructed heat shield surface area can include, for example, portions of the combustion chamber surface 88 that do not include non-cooling apertures (e.g., the shield quench apertures 94) and/or other heat shield features such as, for example, bosses, studs, flanges, rails, etc. connected to the second impingement cavity surface 86. Obstructed heat shield surfaces can include, for example, first regions 128 of the combustion chamber surface opposite shell quench aperture 94 rails, and second regions 130 of the combustion chamber surface opposite studs.
In the specific embodiment of
In some embodiments, the effusion aperture density in one or more of the heat shield cooling regions may change (e.g., intermittently increase and decrease) as the region extends circumferentially around the centerline 24. In the specific embodiment of
Referring to
Referring to
During operation of the combustor 10 of
Cooling air flowing through the impingement apertures in the support shell 30 is subject to a cooling air first pressure drop between the combustor plenum surface 38 and the first impingement cavity surface 40. The magnitude of the first pressure drop is influenced by the number and/or diameter of the impingement apertures. Cooling air flowing through the effusion apertures in the heat shield 32 is subject to a cooling air second pressure drop between the second impingement cavity surface 86 and the combustion chamber surface 88. The magnitude of the second pressure drop is influenced by the number and/or diameter of the effusion apertures. In some embodiments, the numbers and/or diameters of the impingement and effusion apertures are selected such that a ratio of the first pressure drop to the second pressure drop is between about two to one (2:1) and about nine to one (9:1).
Referring to
In some embodiments, for example as illustrated in
In some embodiments, the effusion aperture density of one or more of the axial regions is between about one hundred and about three hundred effusion apertures per unit of combustion chamber surface 88. In general, the effusion aperture density is relatively large where the angular offset between the effusion apertures and the combustion chamber surface 88 is relatively large (e.g., about thirty degrees). The effusion aperture density is relatively small where the angular offset between the effusion apertures and the combustion chamber surface 88 is relatively small (e.g., about fifteen degrees).
In some embodiments, one or more of the heat shields 32 includes a thermal barrier coating (TBC) applied to the combustion chamber surface 88. The thermal barrier coating can include ceramic and/or any other suitable non-ceramic thermal barrier material.
In some embodiments, bosses surrounding the quench apertures (42 or 94) may be interconnected and fluidly separate the cavity 138 into, for example, an axial forward cavity and an axial aft cavity.
While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. For example, the present invention as described herein includes several aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present invention that some or all of these features may be combined within any one of the aspects and remain within the scope of the invention. Accordingly, the present invention is not to be restricted except in light of the attached claims and their equivalents.
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