Abstract:
In a first embodiment a system, including a gas turbine combustor, including an inner wall disposed about a combustion chamber, and an outer wall disposed about the inner wall, wherein a coolant flow path extends between the inner and outer walls, wherein the inner wall comprises a material blocking a plurality of openings, and the plurality of openings are configured to open after the material is consumed or depleted to define a plurality of coolant passages through the inner wall.

Description:
BACKGROUND 
       [0001]    The subject matter disclosed herein relates to gas turbine engines and, more specifically, to a system for protecting an inner wall of a combustor. 
         [0002]    Gas turbine engines may include a combustor having a liner, and a transition piece that connects the combustor to a turbine. As an air-fuel mixture combusts inside of the combustor, the hot combustion gases travel through the combustor and into the turbine, generating power. Unfortunately, the hot combustion gases may oxidize the combustor causing undesirable consumption/depletion. Over time excessive oxidization may result in costly repairs and replacement. 
       BRIEF DESCRIPTION 
       [0003]    In a first embodiment a system, including a gas turbine combustor, including an inner wall disposed about a combustion chamber, and an outer wall disposed about the inner wall, wherein a coolant flow path extends between the inner and outer walls, wherein the inner wall comprises a material blocking a plurality of openings, and the plurality of openings are configured to open after the material is consumed or depleted to define a plurality of coolant passages through the inner wall. 
         [0004]    In a second embodiment a system, including a gas turbine engine, including a coolant flow path, a combustion gas path, and a wall between the coolant flow path and the combustion gas path, wherein a first side of the wall faces the coolant flow path, and a second side of the wall faces the combustion gas path, wherein the wall comprises a material blocking a plurality of openings, and the plurality of openings are configured to open after oxidation of the material to define a plurality of coolant passages through the wall. 
         [0005]    In a third embodiment a system, including a combustion system, including a coolant flow path, a combustion gas path, and a wall between the coolant flow path and the combustion gas path, wherein a first side of the wall faces the coolant flow path, and a second side of the wall faces the combustion gas path, wherein the wall comprises a material blocking a plurality of openings, and the plurality of openings are configured to open after oxidation of the material to define a plurality of coolant passages through the wall. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
           [0007]      FIG. 1  is a block diagram of an embodiment of a gas turbine having a system for protecting an inner wall of a combustor; 
           [0008]      FIG. 2  is a cross-sectional view of an embodiment of a combustor having a system for protecting an inner wall of the combustor; 
           [0009]      FIG. 3  is a partial cross-sectional view of an embodiment of a combustor wall with a thermal barrier coating spallation initiated effusion cooling system within line  3 - 3  of  FIG. 2 ; 
           [0010]      FIG. 4  is a partial cross-sectional view of an embodiment of a combustor wall with a thermal barrier coating spallation initiated effusion cooling system in operation within line  3 - 3  of  FIG. 2 ; 
           [0011]      FIG. 5  is a partial cross-sectional view of an embodiment of a combustor wall with an oxidation initiated effusion cooling system within line  3 - 3  of  FIG. 2 ; 
           [0012]      FIG. 6  is a partial cross-sectional view of an embodiment of a combustor wall with an oxidation initiated effusion cooling system within line  3 - 3  of  FIG. 2 ; 
           [0013]      FIG. 7  is a partial cross-sectional view of an embodiment of a combustor wall with an oxidation initiated effusion cooling system in operation along within line  3 - 3  of  FIG. 2 ; 
           [0014]      FIG. 8  is a partial cross-sectional view of an embodiment of a combustor wall with a thermal barrier coating spallation initiated effusion cooling system and an oxidation initiated effusion cooling system within line  3 - 3  of  FIG. 2 ; 
           [0015]      FIG. 9  is a partial cross-sectional view of an embodiment of a combustor wall with a thermal barrier coating spallation initiated effusion cooling system in operation and an oxidation initiated effusion cooling system within line  3 - 3  of  FIG. 2 ; 
           [0016]      FIG. 10  is a partial cross-sectional view of an embodiment of a combustor wall with a thermal barrier coating spallation initiated effusion cooling system and an oxidation initiated effusion cooling system in operation within line  3 - 3  of  FIG. 2 ; 
           [0017]      FIG. 11  is a partial sectional view of an embodiment of a combustor wall with a system for protecting the inner wall of a combustor along line  11 - 11  of  FIG. 2 ; and 
           [0018]      FIG. 12  is a partial sectional view of an embodiment of a combustor wall with a system for protecting the inner wall of a combustor along line  11 - 11  of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below. 
         [0020]    The disclosed embodiments are generally directed towards a system for protecting an inner wall of a combustor. More specifically, the disclosed embodiments are directed towards an oxidation initiated effusion cooling system, a thermal barrier coating spallation initiated effusion cooling system, or a combination thereof. These systems enable a cooling airflow or protective film to cover the inner wall of the combustor, thereby blocking the hot combustion gases from oxidizing (e.g., depleting, consuming, etc.) the combustor wall. For example, the oxidation initiated effusion cooling system includes blind holes in the combustor wall that open once a portion of the combustor wall oxidizes. After opening, the blind holes provide a cooling airflow or film that protects the combustor wall from further oxidation. In another example, the thermal barrier coating spallation initiated effusion cooling system includes apertures in the combustor wall covered by a thermal barrier coating. After the thermal barrier coating separates from the combustor wall, the apertures open providing a cooling airflow or film that limits oxidization of the combustor wall. In still another example, a combustor may use a combination of apertures and blind holes. Thus, once the thermal barrier coating separates from the combustor wall a cooling airflow or film starts flowing through the apertures. However, if the cooling airflow from the apertures is unable to sufficiently block oxidization, then the continued oxidization may gradually open the blind holes, thus providing additional cooling airflow for protection of the combustor wall against oxidation. 
         [0021]      FIG. 1  is a block diagram of an embodiment of a gas turbine system  10  having a system for protecting an inner wall of a combustor from excessive oxidization of a combustor liner and transition piece. The turbine system  10  may use liquid or gas fuel, such as natural gas and/or a hydrogen rich synthetic gas, to run the turbine system  10 . As depicted, a plurality of fuel nozzles  12  intakes a fuel supply  14 , mixes the fuel with air, and distributes the air-fuel mixture into a combustor  16 . The air-fuel mixture combusts in a chamber within combustor  16 , thereby creating hot pressurized exhaust gases that can potentially oxidize the combustor  16 . Again, the disclosed embodiments provide protection (e.g., cooling airflow) to reduce such oxidation. The combustor  16  directs the exhaust gases through a turbine  18  toward an exhaust outlet  20 . As the exhaust gases pass through the turbine  18 , the gases force one or more turbine blades to rotate a shaft  22  along an axis of the system  10 . As illustrated, the shaft  22  may be connected to various components of turbine system  10 , including a compressor  24 . The compressor  24  also includes blades that may be coupled to the shaft  22 . As the shaft  22  rotates, the blades within the compressor  24  also rotate, thereby compressing air from an air intake  26  through the compressor  24  and into the fuel nozzles  12  and/or combustor  16 . The shaft  22  may also be connected to a load  28 , which may be a vehicle or a stationary load, such as an electrical generator in a power plant or a propeller on an aircraft, for example. As will be understood, the load  28  may include any suitable device capable of being powered by the rotational output of turbine system  10 . 
         [0022]    In operation, air enters the turbine system  10  through the air intake  26  and may be pressurized in the compressor  24 . The compressed air may then be mixed with gas for combustion within combustor  16 . For example, the fuel nozzles  12  may inject a fuel-air mixture into the combustor  16  in a suitable ratio for optimal combustion, emissions, fuel consumption, and power output. The combustion generates hot pressurized exhaust gases, which then drive one or more blades within the turbine  18  to rotate the shaft  22  and, thus, the compressor  24  and the load  28 . The rotation of the turbine blades causes a rotation of shaft  22 , thereby causing blades within the compressor  22  to draw in and pressurize the air received by the intake  26 . 
         [0023]      FIG. 2  is a cross-sectional view of an embodiment of a combustor  16  having a system for protecting an inner wall of the combustor from excessive oxidization. Again, the disclosed embodiments provide protection (e.g., cooling airflow) to reduce such oxidation. As will be appreciated, the combustor  16  is generally fluidly coupled to the compressor  24  and the turbine  18 . The compressor  24  may include a diffuser  40  and a discharge plenum  42  that are coupled to each other in fluid communication to facilitate the channeling of compressed air to the combustor  16 . In the illustrated embodiment, the combustor  16  includes a cover plate  44  at the upstream head end of the combustor  16 . The cover plate  44  may at least partially support the fuel nozzles  12  and provide a path through which air and fuel are directed to the fuel nozzles  12 . 
         [0024]    The combustor  16  includes a combustor liner  46  and transition piece  58  disposed within a flow sleeve  48 . The arrangement of the liner  46  and the flow sleeve  48 , as shown in  FIG. 2 , is generally concentric and may define a passage  50 . In certain embodiments, the flow sleeve  48  and the liner  46  may define a first or upstream hollow annular wall of the combustor  16 . The interior of the liner  46  includes an interior surface  47  and may define a combustion chamber or cavity  52 . The flow sleeve  48  may include a plurality of inlets  54 , which provide a flow path for at least a portion of the air from the compressor  24  into the passage  50 . In other words, the flow sleeve  48  may be perforated with a pattern of openings to define a perforated wall. 
         [0025]    An interior cavity  60  of the transition piece  58  generally provides a path by which combustion gases from the combustion chamber  52  may be directed through a turbine nozzle  62  and into the turbine  18 . In the depicted embodiment, the transition piece  58  may be coupled to the downstream end of the liner  46  (with respect to direction  56 ), generally about a downstream end portion  64  (coupling portion). An annular wrapper  66  and a seal may be disposed between the downstream end portion  64  and the transition piece  58 . The seal may secure the outer surface of the wrapper  66  to the inner surface  68  of the transition piece  58 . 
         [0026]    As discussed above, the turbine system  10 , in operation, may intake air through the air intake  26 . The compressor  24 , which is driven by the shaft  22 , rotates and compresses the air. The compressed air is discharged into the diffuser  40 , as indicated by the arrows shown in  FIG. 2 . The majority of the compressed air is further discharged from the compressor  24 , by way of the diffuser  40 , through a plenum  42  into the combustor  16 . The air in the annular passage  50  is then channeled upstream (e.g., in the direction of fuel nozzles  12 ), such that the air flows over the transition piece  58  and the downstream end portion  64  of the liner  46 . In the illustrated embodiment, the airflow provides forced convection cooling of the transition piece  58  and the liner  46 , as the air is travels upstream towards the fuel nozzles  12  through the annular passage  50 . In the present discussion, the transition piece  58  and the liner  46  both represent an inner wall of the combustor  16 , and include the cooling system discussed in detail below. In the fuel nozzles  12 , the air combines with fuel and ignites within the combustion chamber  52 . The resulting combustion gases are channeled from the chamber  52  into the transition piece cavity  60  and through the turbine nozzle  62  to the turbine  18 . 
         [0027]    As discussed above, the hot combustion gases flow from the chamber  52  through the transition piece  58  to the turbine  18 . The temperature of the combustion gases increases the metal temperature of the liner  46  and transition piece  58 , enabling the metal to combine with oxygen (i.e., the metal oxidizes). The resulting oxidized metal breaks down the combustor  16 . Thus, without sufficient protection, the liner  46  and the transition piece  58  gradually oxidizes (e.g., depletes, is consumed, etc.), resulting in costly repairs and replacement. In order to reduce oxidization, a thermal barrier coating may be used to protect the liner  46  and transition piece  58 . More specifically, the thermal barrier coating covers the interior surface  47  of the liner  46  and the interior surface  68  transition piece  58 , thereby blocking the combustion gases from interacting with the metal alloys (i.e., blocking oxidization). Unfortunately, the thermal barrier coating may gradually erode and/or separate from the liner  46  and transition piece  58 , allowing oxidization. Over time, excessive oxidization may cause undesirable deterioration of the combustor  16 . 
         [0028]      FIG. 3  is a partial cross-sectional view of an embodiment of a combustor wall with a thermal barrier coating (TBC) spallation initiated effusion cooling system  90  within line  3 - 3  of  FIG. 2 . As discussed above, the TBC spallation initiated effusion cooling system  90  protects a combustor wall  92  from excessive oxidation (e.g., depletion, consumption, etc.) with oxidizing combustion gases  94  traveling through a combustor cavity  96 . During operation, the high temperatures of the combustion gases heat the metal. Without protection, the high metal temperatures accelerate oxidation of the metal (i.e., oxygen combines with the metal causing the metal to breakdown). Continued oxidization may therefore lead to excessive depletion/consumption of the metal and thus costly repairs and replacements. As illustrated, the system  90  includes a thermal barrier coating (TBC)  98  covering an interior surface  100  of the combustor wall  92 . Moreover, the system  90  includes multiple apertures  102  in the combustor wall  92  between the exterior surface  104  and the interior surface  100  of the combustor wall  92 . As illustrated, the apertures  102  are uniformly separated a distance  106 , and define uniform widths  108 . In other embodiments, the distance  106  and the aperture widths  108  may differ between apertures  102  (i.e., the apertures  102  may be uniformly or non-uniformly spaced or sized). These apertures  102  facilitate cooling (e.g., effusion cooling, film cooling, etc.) and protection of the interior surface  100  with compressed air  110 , after separation of the TBC  98  (i.e., the apertures  102  open once the TBC  98  separates (e.g., erodes or spalls) from the interior surface  100 ). 
         [0029]      FIG. 4  is a partial cross-sectional view of an embodiment of a combustor wall  92  with a thermal barrier coating spallation initiated effusion cooling system  90  in operation within line  3 - 3  of  FIG. 2 . During operation, the TBC  98  protects the metal combustor wall  92  from the oxidizing combustion gases  94 . The TBC  98  may be a ceramic barrier coating. However, over time the TBC  98  may erode or spall (i.e., be depleted or consumed) from the interior surface  100  leaving the metal interior surface  100  unprotected. As illustrated in  FIG. 3 , the thermal barrier coating  98  has separated (or worn away) from the interior surface  100  of the combustor wall  92 . As explained above, the separation of the TBC  98  opens the apertures  102 , enabling compressed air  110  to flow through the combustor wall  92  and into the combustor cavity  96 . After exiting the apertures  102 , the compressed air  110  creates a film of air  112 . The film of air  112  reduces combustor oxidation (e.g., depletion, consumption, etc.) by cooling the interior surface  100 , which blocks or reduces oxidation of the combustor wall  92 . 
         [0030]      FIG. 5  is a partial cross-sectional view of an embodiment of a combustor wall  120  with an oxidation initiated effusion cooling system  122  within line  3 - 3  of  FIG. 2 . The oxidation initiated effusion cooling system  122 , like the TBC spallation initiated effusion cooling system  90 , protects a combustor wall  120  from excessive oxidation (e.g., depletion, consumption, etc.) from oxidizing combustion gases  124  that travel through a combustor cavity  126 . As explained above, the high temperatures of the combustion gases heat the metal facilitating oxidation (e.g., breakdown of the metal). Continued oxidization may result in excessive depletion/consumption of the combustor wall  120 , and thus costly repairs and replacements. As illustrated, the system  122  may include a thermal barrier coating (TBC)  128  covering an interior surface  130  of the combustor wall  120 . Moreover, the system  122  includes multiple blind holes  132  in an exterior surface  134  of the combustor wall  120 . As illustrated, these blind holes  132  penetrate the combustor wall  120  by a distance  136  from the exterior surface  134 , define equal widths  138 , and are separated from each other by an equal distance  140 . For example, the distance  136  may be approximately 50 to 100, 75 to 99, or 80 to 95 percent of the thickness of the wall  120 . In other embodiments, the blind holes  132  may penetrate more or less into the combustion wall  120 . In still other embodiments, the depth  136  of each blind hole  132  may differ from the other blind holes  132 . Moreover, the width  138  of the blind holes  132  and the distance  140  between blind holes  132  may be uniform or non-uniform in order to provide oxidation protection in specific regions of the combustor wall  120 . During operation, the blind holes  132  (once opened through the wall  120 ) facilitate effusion cooling of the interior surface  130  (i.e., oxidation protection of interior surface  130 ) with compressed air  142 . More specifically, after the TBC  128  separates from the interior surface  130 , the system  122  allows the combustion gases to potentially oxidize (i.e., deplete, consume, etc.) the combustor wall  120  by a distance  144 . After the combustion gases  124  oxidize and remove a portion of the wall  120 , equal to distance  144 , the blind holes  132  open and enable cooling (e.g., effusion cooling, film cooling, etc.) that then protects the wall  120  from further oxidation. 
         [0031]      FIG. 6  is a partial cross-sectional view of an embodiment of the combustor wall without a thermal barrier coating and the oxidation initiated effusion cooling system  122  along line  3 - 3 . During operation, the TBC  128  (seen in  FIG. 5 ) protects the metal combustor wall  122  from the oxidizing combustion gases  124 . However, over time, the TBC  128  may separate (e.g., erode or spall) from the interior surface  130 , leaving the metal interior surface  130  unprotected. As illustrated, without the TBC  128 , the combustion wall  120  is exposed to the combustion gases  124 . Over time, the combustion gases  124  allow oxidation of the wall  120 , and as the wall  120  oxidizes it begins to degrade. After oxidizing (e.g., depleting, consuming, etc.) the wall  120  partially, through a distance  144 , the blind holes  132  open and enable effusion cooling. 
         [0032]      FIG. 7  is a partial cross-sectional view of an embodiment of a combustor wall  120  with an oxidation initiated effusion cooling system  122  in operation within line  3 - 3  of  FIG. 2 . As illustrated, oxidation has worn away the combustor wall  120  by the distance  144 , thereby opening the blind holes  132  completely through the wall  120  from the exterior surface  134  to the interior surface  130 . Once oxidation opens the blind holes  132 , compressed air  142  is able to pass through the combustor wall  120  and into the combustor cavity  126 . As the compressed air  142  enters the combustor cavity  126 , the air  142  creates a film of air  144 . The film of air  144  cools the metal interior surface  130 , while also blocking or reducing further oxidation of the combustor wall  120 . In other words, the film of air  144  creates a protective shield or blanket along the wall  120 , thereby blocking the combustion gas from contacting and oxidizing the surface  130  of the wall  120 . 
         [0033]      FIG. 8  is a partial cross-sectional view of an embodiment of a combustor wall  160  with a thermal barrier coating spallation initiated effusion cooling system  162  and an oxidation initiated effusion cooling system  164  within line  3 - 3  of  FIG. 2 . As illustrated, apertures  166  of the thermal barrier coating spallation initiated effusion cooling system  162  may be used in combination with blind holes  168  and  170  of the oxidation initiated effusion cooling system  164 . The combination of the two systems  162  and  164  enables immediate and delayed effusion cooling protection of the combustor wall  160 . More specifically, loss of a thermal barrier coating  172  enables apertures  166  to provide immediate effusion cooling (e.g., oxidation protection) for the combustor wall  160 . If the apertures  166  are unable to provide adequate oxidation protection, the blind holes  168  and  170  will provide additional effusion cooling (e.g., oxidation protection) as the combustor wall  160  oxidizes and opens the blind holes  168  and  170 . In other words, apertures  166  may provide the primary oxidation protection, while blind holes  168  and  170  function as a secondary protection, in the event the combustor wall  160  oxidizes (e.g., depletes, consumes, etc.) away a portion of the interior surface  174 . 
         [0034]    As illustrated, the apertures  166  define equal widths  176  and depths  178 . As explained above, the widths  176  may be uniform or non-uniform depending on effusion cooling desired on different portions of the combustor wall  160 . Moreover, the apertures  166  completely penetrate the combustor wall  160 , enabling immediate effusion cooling upon removal of the TBC  172 . As will be appreciated, the blind holes  168  and  170  likewise define respective depths  180  and  182 ; and respective widths  184  and  186 . As illustrated, the blind holes  168  and  170  differ in dimensions. Specifically, blind hole  168  defines a depth  180  and width  184  greater than the depth  182  and width  186  of blind hole  170  (e.g., 10, 15, 25, 50, 75, percent greater in depth and width). Accordingly, oxidation of the combustor wall  160  will open blind holes  168  before opening blind hole  170 . Indeed, as oxidation removes an amount of the combustor wall  160  equal to distance  188 , the oxidation opens blind hole  168 . The effusion cooling flowing through the holes  168  then combines with the effusion cooling airflow through the apertures  166 , increasing the overall oxidation protection for the combustor wall  160 . Moreover, if oxidation continues and penetrates a distance  190 , the oxidation will open blind holes  170 , thereby increasing the effusion cooling of the combustor wall  160 . Accordingly, as oxidation increases so does effusion cooling. In other words, the response to oxidation may vary in response to oxidation of the combustor wall  160 . Moreover, blind hole  168  may provide more effusion cooling (i.e., oxidation protection) than the blind hole  170 , because of the difference in widths  184  and  186 . In other embodiments, the depths and widths of the blind holes  168  and  170  may vary. For example, the depths  180  and  182  of the blind holes  168  and  170  may increase, thereby reducing distances  188  and  190 , and thus reducing the amount of oxidation that may occur before the blind holes  168  and  170  open and provide effusion cooling. Moreover, the width of the blind holes  168  and  170  may increase or decrease. An increase in width  184  and  186  expands the capacity of blind holes  168  and  170  to provide greater effusion cooling, while a decrease in the widths  184  and  186  reduces the effusion cooling capacity. Accordingly, various combinations are possible, wherein the depth  182  and/or width of blind hole  170  may be greater than or less than the depth  180  and/or width  186  of the blind hole  168 . Accordingly, the systems  162  and  164  enable a tailored effusion cooling response to oxidation of the combustor wall  160 . 
         [0035]      FIG. 9  is a partial cross-sectional view of an embodiment of a combustor wall  160  with a thermal barrier coating spallation initiated effusion cooling system  162  in operation and an oxidation initiated effusion cooling system  164  within line  3 - 3  of  FIG. 2 . During operation, the TBC  172  (seen in  FIG. 8 ) protects the metal combustor wall  160  from the oxidizing combustion gases  200 . However, over time, the TBC  172  may separate (e.g., spall, erode, or be consumed away) from the interior surface  174 . As illustrated, the separation of the TBC  172  opens the apertures  166  of the thermal barrier coating spallation initiated effusion cooling system  162 . Once open, the apertures  166  enable cooling airflow  192  to pass through the combustor wall  160  into the combustor cavity  194 . As the compressed air  192  enters the combustor cavity  194 , the compressed air  192  creates a cooling airflow or film  196  over the interior surface  174 . The cooling airflow or film  196  provides oxidation protection for the combustor wall  160 . 
         [0036]      FIG. 10  is a partial cross-sectional view of an embodiment of a combustor wall  160  with a thermal barrier coating spallation initiated effusion cooling system  162  and an oxidation initiated effusion cooling system  164  in operation within line  3 - 3  of  FIG. 2 . As illustrated, without the TBC  172 , the combustion wall  160  is exposed to the combustion gases  200 . Over time, the combustion gases  200  may cause oxidation of the wall  160 , and as the wall  160  oxidizes it begins to deplete or be consumed away. After oxidization partially depletes or consumes away the wall  160  by a distance  188 , the blind holes  168  open, enabling additional effusion cooling. More specifically, the compressed air  192  flowing though holes  168  increases the cooling airflow or film  196 , thus blocking or further reducing oxidation of the combustor wall  160 . If oxidation continues to deplete or consume the wall  100  by a distance  190 , the oxidation will open the blind holes  170 , further increasing the cooling airflow or film  196 . In this manner, the system  162  may provide immediate or delayed effusion cooling protection with apertures  166 , while the system  164  may provide delayed or secondary oxidation protection with the blind holes  168  and  170 . 
         [0037]      FIG. 11  is a partial sectional view of an embodiment of a combustor wall  220  with a system  222  for protecting the inner wall of a combustor  16  along line  11 - 11  of  FIG. 2 . The system  222  may be a thermal barrier coating spallation initiated effusion cooling system, an oxidation initiated effusion cooling system, or a combination thereof. Accordingly, the multiple holes  224 , covered by a coating, may be apertures that completely penetrate the combustor wall  220 , blind holes that partially penetrate the combustor wall  220 , or a combination of apertures and blind holes. In the present embodiment, the holes  224  are in rows that alternate between increasing and decreased in size (e.g., diameter), as well as in number. Moreover, the holes  224  may vary in size, spacing, shape, depth, and number along the combustor wall  220  (i.e., non-uniform), enabling the system  222  to provide tailored oxidation protection to specific portions of the combustor. 
         [0038]      FIG. 12  is a sectional view of an embodiment of a combustor wall  240  of  FIG. 2  with a system  242  for protecting the inner wall of a combustor along line  11 - 11 . The system  242  may be a thermal barrier coating spallation initiated effusion cooling system, an oxidation initiated effusion cooling system, or a combination thereof. Accordingly, the multiple holes  244 , covered by a coating, may be apertures that completely penetrate the combustor wall  240 , blind holes that partially penetrate the combustor wall  240 , or a combination of apertures and blind holes. In the present embodiment, the holes  244  are uniform and equally spaced apart. Depending on the embodiment, the holes  244  may be equally spaced apart about the combustor  16  or on a portion of the combustor  16  (i.e., a portion that experiences excess oxidation). In this manner, the system  242  may provide complete or tailored oxidation protection of the entire combustor  16  or a portion thereof. 
         [0039]    The technical effects of the invention include oxidation protection of a combustor wall with a cooling airflow or film. In particular, the disclosed embodiments include a thermal barrier coating spallation initiated effusion cooling system, an oxidation initiated effusion cooling system, or a combination thereof. As discussed above, the two systems provide a cooling airflow or film that reduces excess oxidation (e.g., depletion, consumption, etc.) of a combustor wall. Moreover, the apertures and blind holes associated with each system may vary in width, spacing, depth, shape, and location along the combustor (i.e., the width, spacing, depth and location may be uniform or non-uniform). Moreover, and as discussed above, these wall protection systems may provide immediate or delayed oxidation protection. Specifically, the thermal barrier coating spallation initiated effusion cooling system may provide immediate effusion cooling (i.e., oxidation protection) upon loss of the thermal barrier coating. The oxidation initiated effusion cooling system may provide a delayed response, allowing partial oxidation of the combustor wall before the blind holes open to provide effusion cooling (i.e., oxidation protection). 
         [0040]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.