Abstract:
Disclosed is a combustor seal including a seal support locatable at a first combustor component and having a plurality of through impingement holes. A wave-shaped seal located at the seal support and defining at least one seal cavity between the wave-shaped seal and the seal support. A peak of the wave-shaped seal is locatable at a second combustor component. The wave-shaped seal includes at least one through passageway located upstream of the peak capable of flowing cooling fluid therethrough into the at least one seal cavity and through the plurality of impingement holes thereby cooling the first combustor component. Further disclosed is a combustor including a combustor seal and a method for cooling a first combustor component.

Description:
BACKGROUND 
     The subject invention relates generally to combustors. More particularly, the subject invention relates to cooling of combustion liners of combustors. 
     Air management is an important consideration in combustor design. Air streams provide an oxidizer for a combustion process and also provide cooling to hot components of the combustor. Seals are typically provided between various components of the combustor to prevent air from leaking into the combustor at unwanted locations. These seals typically include C-Rings, fingered hula rings, cloth seals, and the like, and are subjected to high temperature and pressure as well as high gradients of pressure and temperature across the seals. In modern combustors, high flame temperatures drive a need to actively cool virtually all metal surfaces of the combustor. One method of actively cooling the combustor components in the area of a liner hula seal is to direct cooling air within cooling channels formed between a seal support and one or more of the combustor components to convectively cool the components. Cooling air typically enters the cooling channels through a series of holes in the seal support at an upstream end of the seal support. The cooling air flows within the cooling channels through an entire length of the seal, thereby cooling the first combustor component by convective heat transfer. As the cooling air flows along the channels, however, its efficiency in cooling the component decreases. To counter the loss of efficiency, larger amounts of cooling air are directed through the cooling channels to provide adequate cooling of the component. In combustors, especially those utilized in lean premixed gas turbine engines it is desirable to reduce the amount of air used for cooling to increase the amount of air directed through the fuel nozzles thereby achieving a uniform, lean-premixed fuel to air ratio to increase combustor performance. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one aspect of the invention, a combustor seal assembly includes a seal support having a plurality of through impingement holes and locatable at a first combustor component. A wave-shaped seal is located at the seal support and defines at least one seal cavity between the wave-shaped seal and the seal support. A peak of the wave-shaped seal is locatable at a second combustor component. The wave-shaped seal includes at least one through passageway located upstream of the peak capable of flowing cooling fluid therethrough into the at least one seal cavity and through the plurality of impingement holes thereby cooling the first combustor component. 
     According to another aspect of the invention, a combustor includes a first combustor component and a second combustor component. The first combustor component is at least partially insertable into the second combustor component, the first combustor component and second combustor component defining a combustion fluid pathway. A combustor seal assembly is located between the first combustor component and the second combustor component. The combustor seal assembly includes a seal support located at the first combustor component and having a plurality of through impingement holes, and a wave-shaped seal disposed at the seal support and defining at least one seal cavity between the wave-shaped seal and the seal support. A peak of the wave-shaped seal is located at a second combustor component. The wave-shaped seal includes at least one through passageway upstream of the peak capable of flowing cooling fluid therethrough into the at least one seal cavity and through the plurality of impingement holes thereby cooling the first combustor component. 
     According to yet another aspect of the invention, a method for cooling a first combustor component includes locating a combustor seal assembly radially between the first combustor component and a second combustor component. The first combustor component is at least partially insertable into the second combustor component, the first combustor component and second combustor component defining a combustion fluid pathway. Cooling fluid is flowed into at least one through passageway in an upstream portion of a wave-shaped seal of the combustor seal into at least one seal cavity defined by the wave-shaped seal and a seal support. The cooling fluid is flowed from the at least one seal cavity through a plurality of impingement holes in the seal support in flow communication with the first combustor component thereby cooling the first combustor component. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a cross-sectional view of an embodiment of a turbomachine; 
         FIG. 2  is a cross-sectional view of an embodiment of a combustor seal; 
         FIG. 3  is a plan view of the combustor seal of  FIG. 2 ; 
         FIG. 4  is a cross-sectional view illustrating an embodiment of cooling channels in a combustor component; and 
         FIG. 5  is a cross-sectional view of an alternative embodiment of a combustor seal. 
     
    
    
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Shown in  FIG. 1  is a partial view of a gas turbine  10 . Compressed fluid is provided to a combustor  12  from, for example, a compressor (not shown). Fuel is injected into the combustor  12 , mixes with the compressed fluid and is ignited. The hot gas product of the combustion flows to a turbine  14  which extracts work from the hot gas. A transition piece  16  is coupled at an upstream end  18  to the combustor  12  at a combustor liner  20  and at a downstream end  22  to an aft frame  24  of the turbine  14 . The transition piece  16  carries hot gas flow from the combustor liner  20  to the turbine  14 . The combustor  12  includes a combustor sleeve  26  spaced radially outward from the combustor liner  20  defining a combustor flow channel  28  therebetween. A combustor cap  30  is coupled to an upstream end  32  of the combustor liner  20  and includes at least one nozzle  34  disposed therein and extending into a combustion chamber  36  defined by the combustor cap  30  and the combustor liner  20 . An impingement sleeve  38  is coupled to the combustor sleeve  26  and is radially spaced from the transition piece  16  defining a transition flow channel  40  therebetween. 
     During operation, discharge flow  42  flows from the compressor through a diffuser  44  to the impingement sleeve  38 . The discharge flow  42  proceeds through a plurality of holes  46  in the impingement sleeve  38  and toward the combustor  12  in the transition flow channel  40 . The discharge flow  42  proceeds from the transition flow channel  40  and through the combustor flow channel  28  until it is finally introduced to the combustor liner  20  through the at least one nozzle  34 . In addition to providing air to the combustor  12  for the combustion process, the relatively cool discharge flow  42  further provides much needed cooling to the components exposed to hot combustion gas, for example, the combustor liner  20  and the transition piece  16 . 
     As shown in  FIG. 2 , interfaces between adjacent components exposed to hot combustion gas, for example, the transition piece  16  and the combustor liner  20 , are configured as lap joints wherein, for example, a downstream end  50  of the combustor liner  20  is configured to be insertable into the upstream end  18  of the transition piece  16 . A seal, for example a hula seal  52 , is disposed radially between the overlapping portions of the transition piece  16  and the combustor liner  20  and extends perimetrically around the joint. In one embodiment, the hula seal  52  is configured with a wave-shaped cross section and includes two layers, an outer layer  54  and an inner layer  56 . The hula seal  52  is configured and disposed with at least one peak  58 , such that the at least one peak  58  in the outer layer  54  contacts the transition piece  16 . In some embodiments, the hula seal  52  includes at least one seal support  60  disposed between the inner layer  56  and combustor liner  20 . The outer layer  54  and the inner layer may be secured to at least one seal support  60  by, for example, at least one weld  62  at an upstream end  64  of the hula seal  52 . Although the at least one weld  62  of the embodiment shown in  FIG. 2  is disposed at the upstream end  64 , in other embodiments the at least one weld  62  may be disposed at a downstream end  66  of the hula seal  52 . 
     As shown in  FIG. 3 , the outer layer  54  and the inner layer  56  comprise a plurality of outer layer fingers  68  and inner layer fingers  70 , respectively. The outer layer fingers  68  extend from a rim  72  and include an outer gap  74  between adjacent outer layer fingers  68 . Similarly, the inner layer fingers  70  extend from the rim  72  and include an inner gap  78  between adjacent inner layer fingers  70 . The inner layer fingers  70  and outer layer fingers  68  are configured such that when the outer layer  54  is placed over the inner layer  56 , a covered length  80  of the inner gap  78  is covered by the outer layer fingers  68 . A perimetrical location of an open length  82  of the inner gap  78 , however, corresponds to a perimetrical location of at least a portion of the outer gap  74 , thus creating a plurality of thru passageways  84  through both the outer layer  54  and inner layer  56 . The plurality of thru passageways  84  are disposed in only an upstream portion  86  of the hula seal  52 , upstream of the at least one peak  58 , thus preventing air from the flow channel  40  from entering the combustion chamber  36 . To achieve a hula seal  52  having covered lengths  80  and open lengths  82 , one or both of the outer gap  74  and the inner gap  78  at each gap location may have a change of direction  90 , across which the inner gap  78  extends in a different direction than the outer gap  74 , thus creating the covered length  80  via an overlap of an inner layer finger  70  and the outer layer finger  68 . 
     Referring again to  FIG. 2 , the at least one seal support  60  includes a plurality of through impingement holes  92  through which discharge flow  42  is directed to impinge upon and thus cool the combustor liner  20  beneath the at least one seal support  60 . In some embodiments, the plurality of impingement holes  92  is disposed along an entire length of the hula seal  52 , including between the upstream end  64  of the hula seal  52  and the downstream end  66  of the hula seal  66 . Discharge air  42  enters a seal cavity  94  between the inner layer  56  and the at least one seal support  60  through the plurality of passageways  84 . The discharge air  42  is directed through the plurality of impingement holes  92  to impinge on the combustor liner  20 , thus cooling the portion of the combustor liner  20  directly beneath the hula seal  52  and the at least one seal support  60 . Besides serving to cool the combustor liner  20 , the discharge air  42  entering the seal cavity  94  also cools the hula seal  52  to prevent failure of the hula seal  52 . 
     In some embodiments, as shown in  FIG. 4 , a plurality of cooling channels  96  are disposed between the at least one seal support  60  and the combustor liner  20 . The plurality of cooling channels  96  may be formed, for example, as shown in  FIG. 4 , by forming the plurality of cooling channels  96  into the combustor liner  20 , or alternatively by forming the plurality of cooling channels  96  into the at least one seal support  60 , or a combination of the two. The plurality of cooling channels  96  are configured and disposed such that discharge flow  42  entering the plurality of impingement holes  92  flows through the cooling channels  96  and into the combustion chamber  36 . Thus the discharge flow  42  cools the combustor liner  20  both by impingement along the entire length of the seal support  60  and also by convective flow through the plurality of cooling channels  96 . 
     An alternative embodiment is illustrated in  FIG. 5 . In this embodiment, the plurality of cooling channels  96  are formed by disposing at least one support leg  98  between the at least one seal support  60  and the combustor liner  20 . The discharge flow  42  flows through the plurality of cooling channels  96  as described above and exits the plurality of cooling channels  96  via at least one exit hole  100  disposed in a downstream support leg  102 . 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.