Patent Publication Number: US-2016238249-A1

Title: Combustor wall having cooling element(s) within a cooling cavity

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Appln. No. 61/892,883 filed Oct. 18, 2013, which is hereby incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This disclosure relates generally to a turbine engine and, more particularly, to a combustor for a turbine engine. 
     2. Background Information 
     A floating wall combustor for a turbine engine typically includes a bulkhead that extends radially between inner and outer combustor walls. Each of the combustor walls includes a shell and a heat shield, which defines a radial side of a combustion chamber. Cooling cavities extend radially between the heat shield and the shell. These cooling cavities fluidly couple impingement apertures in the shell with effusion apertures in the heat shield. 
     There is a need in the art for an improved turbine engine combustor. 
     SUMMARY OF THE DISCLOSURE 
     According to an aspect of the invention, a combustor wall is provided for a turbine engine. The combustor wall includes a shell, a heat shield and a cooling element. The shell defines a first set of apertures. The heat shield defines a second set of apertures. The cooling element extends between the shell and the heat shield within a tapered cooling cavity, which is defined between the shell and the heat shield. The tapered cavity is fluidly coupled with the first and the second sets of apertures, and the cooling element is thermally coupled to one of the shell and the heat shield. 
     According to another aspect of the invention, a combustor is provided for a turbine engine. The combustor includes a combustor shell, a combustor heat shield and a cooling element. The combustor shell defines a first set of apertures. The combustor heat shield defines a second set of apertures, and is attached to the shell. The shell and the heat shield at least partially define a cooling cavity therebetween with the cooling element extending into the cooling cavity and the cooling cavity fluidly coupling the first and the second sets of apertures. 
     The cooling element may be configured as or otherwise include a positive dimple. 
     The cooling element may be configured as or otherwise include a rib. 
     The cooling element may include a concave outer surface that extends within the cooling cavity. 
     The cooling element may include a convex outer surface that extends within the cooling cavity. 
     The cooling element may include a wall defining an indentation. 
     The cooling element may extend from the heat shield. 
     The first set of apertures may include an impingement aperture adapted to direct air into the cooling cavity to impinge against the cooling element. 
     The combustor wall may include a second cooling element that extends into the cooling cavity from the shell. 
     The combustor wall may further include a second cooling element and a third cooling element which each extend into the cooling cavity from the shell. The cooling element may be positioned opposite and between the second and the third cooling elements. 
     The combustor wall may include a second cooling element that extends into the cooling cavity from the heat shield. The second set of apertures may include an aperture positioned opposite and between the cooling element and the second cooling element. 
     The cooling element may extend into the cooling cavity from the shell. 
     The tapered cooling cavity may include a tapered portion defined by respective portions of the shell and the heat shield converging toward one another. 
     The combustor wall may be a tubular combustor wall that extends along a centerline. The cooling cavity may extend radially between the shell and the heat shield. The cooling element may extend radially into the cooling cavity. 
     The shell and the heat shield may be configured to couple to a combustor bulkhead at an upstream end thereof. 
     The cooling element may extend into the cooling cavity from the heat shield. The first set of apertures may include an impingement aperture configured to direct air into the cooling cavity to impinge against the cooling element. 
     The cooling cavity may include a tapered portion defined by respective portions of the shell and the heat shield that converge toward one another. 
     The combustor may include a plurality of additional cooling elements. The cooling element and each of the additional cooling elements may extend a respective height into the cooling cavity. The respective heights of the cooling elements may vary along the shell and the heat shield. 
     The combustor may include a first combustor wall. The shell, the heat shield and the cooling element may be included within a combustor second wall. The first and the second combustor walls may be configured to be coupled a combustor bulkhead. 
     The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side cutaway illustration of a geared turbine engine; 
         FIG. 2  is a side cutaway illustration of a portion of a combustor section; 
         FIG. 3  is a perspective illustration of a portion of a combustor; 
         FIG. 4  is a perspective illustration of a portion of a combustor wall; 
         FIG. 5  is a side sectional illustration of a portion of the combustor wall; 
         FIG. 6  is another side sectional illustration of a portion of the combustor wall; 
         FIG. 7  is an illustration of a heat shield panel; 
         FIG. 8  is another side sectional illustration of a portion of the combustor wall; 
         FIG. 9  is a side sectional illustration of a portion of an alternate embodiment combustor wall; 
         FIG. 10  is a side sectional illustration of a portion of an alternate embodiment combustor wall; and 
         FIG. 11  is a side sectional illustration of a portion of an alternate embodiment combustor wall. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a side cutaway illustration of a geared turbine engine  20 . This turbine engine  20  extends along an axial centerline  22  between an upstream airflow inlet  24  and a downstream airflow exhaust  26 . The turbine engine  20  includes a fan section  28 , a compressor section  29 , a combustor section  30  and a turbine section  31 . The compressor section  29  includes a low pressure compressor (LPC) section  29 A and a high pressure compressor (HPC) section  29 B. The turbine section  31  includes a high pressure turbine (HPT) section  31 A and a low pressure turbine (LPT) section  31 B. The engine sections  28 - 31  are arranged sequentially along the centerline  22  within an engine housing  34 , which includes a first engine case  36  (e.g., a fan nacelle) and a second engine case  38  (e.g., a core nacelle). 
     Each of the engine sections  28 ,  29 A,  29 B,  31 A and  31 B includes a respective rotor  40 - 44 . Each of the rotors  40 - 44  includes a plurality of rotor blades arranged circumferentially around and connected to (e.g., formed integral with or mechanically fastened, welded, brazed, adhered or otherwise attached to) one or more respective rotor disks. The fan rotor  40  is connected to a gear train  46  (e.g., an epicyclic gear train) through a shaft  47 . The gear train  46  and the LPC rotor  41  are connected to and driven by the LPT rotor  44  through a low speed shaft  48 . The HPC rotor  42  is connected to and driven by the HPT rotor  43  through a high speed shaft  50 . The shafts  47 ,  48  and  50  are rotatably supported by a plurality of bearings  52 . Each of the bearings  52  is connected to the second engine case  38  by at least one stator such as, for example, an annular support strut. 
     Air enters the turbine engine  20  through the airflow inlet  24 , and is directed through the fan section  28  and into an annular core gas path  54  and an annular bypass gas path  56 . The air within the core gas path  54  may be referred to as “core air”. The air within the bypass gas path  56  may be referred to as “bypass air”. 
     The core air is directed through the engine sections  29 - 31  and exits the turbine engine  20  through the airflow exhaust  26 . Within the combustor section  30 , fuel is injected into an annular combustion chamber  58  (see also  FIG. 2 ) and mixed with the core air. This fuel-core air mixture is ignited to power the turbine engine  20  and provide forward engine thrust. The bypass air is directed through the bypass gas path  56  and out of the turbine engine  20  through a bypass nozzle  60  to provide additional forward engine thrust. Alternatively, the bypass air may be directed out of the turbine engine  20  through a thrust reverser to provide reverse engine thrust. 
       FIG. 2  illustrates an assembly  62  of the turbine engine  20 . This turbine engine assembly  62  includes a combustor  64 . The turbine engine assembly  62  also includes one or more fuel injector assemblies  66 , each of which may include a fuel injector  68  mated with a swirler  70 . 
     The combustor  64  may be configured as an annular floating wall combustor, which may be arranged within an annular plenum  72  of the combustor section  30 . The combustor  64  of  FIGS. 2 and 3 , for example, includes an annular combustor bulkhead  74 , a tubular combustor inner wall  76 , and a tubular combustor outer wall  78 . The bulkhead  74  extends radially between and is connected to the inner wall  76  and the outer wall  78 . The inner wall  76  and the outer wall  78  each extends axially along the centerline  22  from the bulkhead  74  towards the turbine section  31 A, thereby defining the combustion chamber  58 . 
     Referring to  FIG. 2 , the inner wall  76  and the outer wall  78  may each have a multi-walled structure; e.g., a hollow dual-walled structure. The inner wall  76  and the outer wall  78  of  FIG. 2 , for example, each includes a tubular combustor shell  80 , a tubular combustor heat shield  82 , and one or more cooling elements  84  and  86  (see  FIG. 4 ). The inner wall  76  and the outer wall  78  also each include one or more cooling cavities  88  (e.g., impingement cavities) and one or more quench apertures  90 , which are arranged circumferentially around the centerline  22 . 
     Referring to  FIG. 4 , the shell  80  includes a shell base  92 , one or more of the cooling elements  84 , and one or more cooling apertures  94 . Referring now to  FIG. 2 , the shell base  92  extends axially along the centerline  22  between an upstream end  96  and a downstream end  98 . The shell base  92  is connected to the bulkhead  74  at the upstream end  96 . The shell base  92  may be connected to a stator vane assembly  100  or the HPT section  31 A at the downstream end  98 . 
     Referring to  FIG. 4 , the cooling elements  84  are formed integral with, or may be attached to, the shell base  92 . The cooling elements  84  may be arranged into one or more axial sets (e.g., sets  102 - 104 ). These axial sets (e.g., sets  102 - 104 ) are respectively arranged at discrete locations along the centerline  22 . Each axial set (e.g., each set  102 - 104 ) includes an array of one or more of the cooling elements  84 , which elements are arranged circumferentially around the centerline  22 . Each of the cooling elements  84  may radially extend partially into a respective one of the cooling cavities  88  from the shell base  92  to a distal end  106 . 
     Referring to  FIGS. 4 and 5 , one or more of the cooling apertures  94  may each be configured as an impingement aperture. Each cooling aperture  94 , for example, may direct core air from the plenum  72  into a respective one of the cooling cavities  88  to impinge against a respective one of the cooling elements  86  to cool the heat shield  82 . One or more of the cooling apertures  94  may each be aligned axially and/or circumferentially between respective adjacent cooling elements  86 ; e.g., approximately centered between a cluster of (e.g., four) respecting cooling elements  86 . 
     Referring to  FIG. 2 , the heat shield  82  extends axially along the centerline  22  between an upstream end and a downstream end. The heat shield  82  may include one or more heat shield panels  108  (e.g., arcuate shaped panels). These panels  108  may be arranged into one or more axial sets. Each of the axial sets is arranged at discrete locations along the centerline  22 . The panels  108  in each set are disposed circumferentially around the centerline  22  and form a hoop. Alternatively, the heat shield  82  may be configured from one or more tubular bodies. 
       FIGS. 6 and 7  illustrate an exemplary one of the panels  108 . It should be noted that each panel  108  may include one or more of the cooling elements  86  and one or more cooling apertures  110  (see  FIG. 4 ) as described below in further detail. For ease of illustration, however, the panel  108  of  FIGS. 6 and 7  is shown without the cooling elements  86  and the cooling apertures  110 . 
     Each of the panels  108  includes a panel base  112  and one or more rails  114 - 117 . The panel base  112  may be configured as a generally curved (e.g., arcuate) plate. The panel base  112  extends axially between an upstream axial end  118  and a downstream axial end  120 . The panel base  112  extends circumferentially between opposing circumferential ends  122  and  124 . 
     Each of the rails  114 - 117  extends radially out from (or in from) the panel base  112  relative to the centerline  22 . The rail  116  is arranged at (e.g., on, adjacent or proximate) the circumferential end  122 . The rail  117  is arranged at the circumferential end  124 . Each of the rails  114  and  115  extends circumferentially between and is connected to the rails  116  and  117 . The rail  114  is arranged at the upstream end  118 . The rail  115  is arranged at the downstream end  120 . 
     Referring to  FIG. 4 , one or more of the panels  108  also each includes one or more of the cooling elements  86  and one or more of the cooling apertures  110  as described above. The cooling elements  86  may be arranged into one or more axial sets (e.g., sets  126 - 129 ). These axial sets (e.g., sets  126 - 129 ) are respectively arranged at discrete locations along the centerline  22 . Each axial set (e.g., each set  126 - 129 ) includes an array of one or more of the cooling elements  86 , which elements are arranged circumferentially around the centerline  22 . Each of the cooling elements  86  may radially extend partially into a respective one of the cooling cavities  88  from the panel base  112  to a distal end  130 . Referring to  FIGS. 4 and 5 , one or more of the cooling elements  86  may each be aligned axially and/or circumferentially with a respective one of the cooling apertures  94 . One or more of the cooling elements  86  may each be aligned axially and/or circumferentially between respective adjacent cooling elements  84 ; e.g., approximately centered between a cluster of (e.g., four) respecting cooling elements  84 . 
     Referring to  FIGS. 4 and 8 , one or more of the cooling apertures  110  may each be configured as an effusion aperture. Each cooling aperture  110 , for example, may direct core air from a respective one of the cooling cavities  88  into the combustion chamber  58  to film cool the heat shield  82 ; e.g., to film cool the panel  108  of the heat shield  82 . One or more of the cooling apertures  110  may each be aligned axially and/or circumferentially with a respective one of the cooling elements  84 . One or more of the cooling apertures  110  may each be aligned axially and/or circumferentially (e.g., diagonally) between respective adjacent cooling elements  86 ; e.g., approximately centered between a cluster of (e.g., four) respecting cooling elements  86 . 
     Referring to  FIG. 2 , the heat shield  82  of the inner wall  76  circumscribes the shell  80  of the inner wall  76 , and defines a radially inner side of the combustion chamber  58 . The heat shield  82  of the outer wall  78  is arranged radially within the shell  80  of the outer wall  78 , and defines a radially outer side of the combustion chamber  58  that is opposite the inner side. 
     The heat shield  82  and, more particularly, each of the panels  108  may be respectively attached to the shell  80  by a plurality of mechanical attachments  132  (e.g., threaded studs). The shell  80  and the heat shield  82  thereby respectively form the cooling cavities  88  in each of the walls  76 ,  78 . 
     The cooling cavities  88  may be arranged into one or more axial sets. These axial sets are respectively arranged at discrete locations along the centerline  22 . Each axial set includes an array of one or more of the cooling cavities  88 , which cavities are arranged circumferentially around the centerline  22  (e.g., at a common axial extent). Referring to  FIG. 4 , each of the cooling cavities  88  fluidly couples one or more of the cooling apertures  94  with one or more of the cooling apertures  110 . 
     Referring to  FIG. 7 , each cooling cavity  88  extends circumferentially between the rails  116  and  117  of a respective one of the panels  108 . Each cooling cavity  88  extends axially between the rails  114  and  115  of a respective one of the panels  108 . 
     Referring to  FIG. 6 , each cooling cavity  88  extends radially between the shell  80  and the panel base  112  of a respective one of the panels  108 , thereby defining a height  134  (e.g., a radial height) of the cooling cavity  88 . In the embodiment of  FIG. 6 , the height  134  changes (e.g., decreases) along an axial upstream direction, from a mid-region  136  of the panel to the rail  114 . The height  134  also changes (e.g., decreases) along an axial downstream direction, from the mid-region  136  to the rail  115 . The height  134  at the rails  114  and  115 , for example, may be less than the height  134  in the mid-region  136 ; e.g., between about one half (½) and about one sixteenth ( 1/16) of the height  134  in the mid-region  136 . This cooling cavity  88  therefore has a double tapered sectional geometry. One or more of the cooling cavities  88 , of course, may alternatively each have a single tapered sectional geometry, or a non-tapered sectional geometry (i.e., a substantially constant height). 
     The cooling cavity  88  tapered geometry is defined by axial portions  138  and  140  of the shell  80  and axial portions  142  and  144  of the heat shield  82 . These portions  138 ,  140 ,  142  and  144  of the shell  80  and the heat shield  82  respectively radially converge towards one another as each respective panel  108  extends axially away from the mid-region  136 . Each shell portion  138  and  140 , for example, has a curvilinear (e.g., an elliptical, parabolic or logarithmic) sectional geometry that extends radially towards a respective one of the heat shield portions  142  and  144 , which each have a substantially flat sectional geometry. 
     Referring to  FIGS. 4 and 5 , core air from the plenum  72  is directed into each cooling cavity  88  through the respective cooling apertures  94  during turbine engine operation. This core air (e.g., cooling air) may impinge against one or more of the cooling elements  86  (and/or the panel base  112 ) and thereby impingement cool the heat shield  82 . For example, thermal energy may be transferred from the cooling elements  86  into the cooling air, which may cause the cooling elements  86  to conductively draw thermal energy out of the panel base  112 . The cooling air may subsequently flow axially and/or circumferentially within the cooling cavity  88 . The axially flowing cooling air may be accelerated by the tapered sectional geometry of the cooling cavity  88  as it flows towards one or more of the rails  114  and  115  (see  FIGS. 6 and 7 ). The axially and/or circumferentially flowing cooling air may pass over one or more of the cooling elements  86 , which may transfer thermal energy into the cooling air as well as turbulate the cooling air. In this manner, the core air within the cooling cavity  88  may also convectively cool the heat shield  82 . Referring to  FIGS. 4 and 8 , the core air within each cooling cavity  88  is subsequently directed through the respective cooling apertures  110  into the combustion chamber  58  to film cool a downstream portion of the heat shield  82 . 
       FIGS. 5 and 8-11  illustrate various cooling element  84 ,  86  configurations. Some of these cooling element configurations are described below and/or illustrated with respect to one of the cooling elements  86 . Some of the cooling element configurations are described below and/or illustrated with respect to one of the cooling elements  84 . It should be noted, however, that one or more of the cooling elements  84  may have similar configurations as those described below and/or illustrated with respect to the cooling elements  86 , and vice versa. 
     The cooling element  86  of  FIG. 5  is configured as a solid positive dimple. The term “positive dimple” may describe a discrete point protrusion (e.g., bump) with a generally parti-spherical (e.g., hemispherical), conical, convex, or cubical geometry. Each cooling element  86  of  FIGS. 4 and 5 , for example, has a hemispherical geometry with a circular cross-section. A positive dimple, however, may alternatively have a solid or annular geometry with a non-circular cross-section such as, for example, an elliptical cross-section, an oval cross-section, a rectangular cross-section, etc. Referring again to  FIG. 5 , the cooling element  86  has an outer surface  146  with a convex sectional geometry. The cooling element  86  extends partially into the cooling cavity  88  to a relatively blunt tip at the distal end  130 . 
     The cooling element  84  of  FIG. 8  is configured as a hollow positive dimple. For example, referring to  FIGS. 4 and 8 , each cooling element  84  has a generally hemispherical wall that defines an interior space  148  in communication with a through-hole  149  in the shell  80 ; e.g., the space  148  is fluidly coupled with the plenum  72  by the through-hole  149 . The cross-section of the cooling element  84  may be annular (e.g., ring shaped) and may have a circular geometry. Alternatively, the through-hole  149  may be omitted such that the interior space  148  (e.g., a cavity) is fluidly isolated from the plenum  72  by the shell base  92  as illustrated in  FIG. 9 . 
     Each cooling element  86  of  FIG. 10  is configured as a hollow positive dimple. Each cooling element  86  has a generally conical wall that defines a fluidly isolated interior space  150 . The cross-section of the cooling element  86  may be annular and may have a circular geometry. Each cooling element  86  has an outer surface  152  with a concave (e.g., parabolic) sectional geometry. Each cooling element  86  extends partially into the cooling cavity  88  to a relatively sharp tip (e.g., a pointed tip) at the distal end  130 . 
     Each cooling element  86  of  FIG. 11  is configured as a solid positive dimple. Each cooling element  86  has a generally tapered tubular wall that defines an indentation  154 , which is fluidly coupled with the cavity  88 . The cross-section of the cooling element  86  may be annular and may have a circular geometry. The indentation  154  extends partially into (or through) the cooling element  86  from the distal end  130 . The indentation  154  may be aligned substantially co-axial with a respective one of the cooling apertures  94 . The surface defining the indentation  154  increases the overall surface area of the cooling element  86 , and may increase a turbulating effect of the cooling element  86  on the core air flowing through the cooling cavity  88 . 
     While the various cooling element  84 ,  86  configurations are described above, the combustor  64  may also or alternatively include one or more of cooling elements with various configurations other than those described above and illustrated in the drawings. For example, in some embodiments, the cooling elements  86  of  FIG. 10  may be solid and the cooling elements  86  of  FIG. 11  may be hollow. In some embodiments, the outer surface  152  of the cooling element  86  of  FIG. 10  may have a straight or convex sectional geometry. In some embodiments, one or more of the cooling elements  84  and/or  86  may each be configured as a rib (e.g., a rail or turbulating strip). This rib may have similar outer surface configurations, etc. as the positive dimples described above and illustrated in the drawings except for being elongated; e.g., its length is more than 2 times its width. In some embodiments, some of the cooling elements  84  and/or  86  may have different heights. For example, radial heights of the cooling elements  86  and  88  to their distal ends  106  and  130  may respectively increase as the respective cooling cavity  88  tapers (or expands). The present invention therefore is not limited to any particular cooling element configurations. 
     The shell  80  and/or the heat shield  82  may each have a configuration other than that described above. In some embodiments, for example, one or more of the shell portions  138  and  140  (see  FIG. 6 ) may each have a substantially flat sectional geometry, and one or more of the heat shield portions  142  and  144  may each have a curvilinear sectional geometry that extends radially towards the respective shell portions  138  and  140 . In some embodiments, both the shell portions  138  and  140  and the heat shield portions  142  and  144  may have curvilinear sectional geometries that extend radially toward one another. In some embodiments, the shell portions  138  and  140  and/or the heat shield portions  142  and  144  may have non-curvilinear sectional geometries that extend radially toward one another. In some embodiments, each panel may define one or more additional cooling cavities with the shell  80 . The present invention therefore is not limited to any particular combustor wall configurations. 
     In some embodiments, the bulkhead  74  may also or alternatively be configured with a multi-walled structure (e.g., a hollow dual-walled structure) similar to that described above with respect to the inner wall  76  and the outer wall  78 . The bulkhead  74 , for example, may include a shell, a heat shield, one or more cooling elements, and one or more cooling cavities. 
     The terms “upstream”, “downstream”, “inner” and “outer” are used to orientate the components of the turbine engine assembly  62  and the combustor  64  described above relative to the turbine engine  20  and its centerline  22 . However, one or more of these components may be utilized in other orientations than those described above. The present invention therefore is not limited to any particular spatial orientations. 
     The turbine engine assembly  62  may be included in various turbine engines other than the one described above. The turbine engine assembly  62 , for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the turbine engine assembly  62  may be included in a turbine engine configured without a gear train. The turbine engine assembly  62  may be included in a geared or non-geared turbine engine configured with a single spool, with two spools (e.g., see  FIG. 1 ), or with more than two spools. The turbine engine may be configured as a turbofan engine, a turbojet engine, a propfan engine, or any other type of turbine engine. The present invention therefore is not limited to any particular types or configurations of turbine engines. 
     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 with 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.