Abstract:
A method facilitates the operation of a gas turbine engine that includes a combustor including a combustion chamber. The method comprises supplying fuel to the combustion chamber, and directing compressed airflow through a combustor dome assembly that includes a splashplate and a unitarily formed flare cone, such that at least a portion of the compressed airflow is channeled axially downstream through at least one cooling passage defined between the flare cone and the splashplate for cooling of the dome assembly.

Description:
BACKGROUND OF THE INVENTION 
   This application relates generally to gas turbine engines and, more particularly, to combustors for gas turbine engine. 
   Combustors are used to ignite fuel and air mixtures in gas turbine engines. Known combustors include at least one dome attached to a combustor liner that defines a combustion zone. Fuel injectors are attached to the combustor in flow communication with the dome and supply fuel to the combustion zone. Fuel enters the combustor through a dome assembly attached to a spectacle or dome plate. 
   The dome assembly includes an air swirler secured to the dome plate, and radially inward from a flare cone. The flare cone is divergent and extends radially outward from the air swirler to facilitate mixing the air and fuel, and spreading the mixture radially outwardly into the combustion zone. A divergent splashplate extends circumferentially around the flare cone and radially outward from the flare cone. The splashplate prevents hot combustion gases produced within the combustion zone from impinging upon the dome plate. 
   To facilitate reducing temperatures of the splashplate, at least some known combustor dome assemblies supply cooling air for convection cooling of the dome assembly through a gap extending partially circumferentially between the flare cone and the splashplate. Such dome assemblies are complex, multi-piece assemblies that require multiple brazing operations to fabricate and assemble. In addition, during use the cooling air may mix with the combustion gases and adversely effect combustor emissions. 
   Because multi-piece combustor dome assemblies are also complex to disassemble for maintenance purposes, at least some other known combustor dome assemblies include one-piece assemblies. However, such assemblies still require pre-assembly welding and as such, may adversely impact splashplate and flare cone durability. 
   BRIEF SUMMARY OF THE INVENTION 
   In one aspect, a method for operating a gas turbine engine including a combustion chamber is provided. The method comprises supplying fuel to the combustion chamber, and directing compressed airflow through a combustor dome assembly that includes a splashplate and a unitarily formed flare cone, such that at least a portion of the compressed airflow is channeled through at least one cooling passage defined between the flare cone and the splashplate for cooling of the splashplate. 
   In another aspect, a combustor for a gas turbine engine is provided. The combustor comprises a dome assembly including a unitary body that includes a splashplate, a flare cone, and at least one cooling passage defined therebetween for discharging cooling air for cooling the splashplate. 
   In a further aspect, a gas turbine engine is provided. The gas turbine engine comprises a combustor that includes an annular dome assembly. The combustor includes an air swirler and a unitary body that extends circumferentially around the air swirler. The unitary body includes a splashplate, a flare cone, and at least one cooling passage that extends therebetween. The at least one cooling passage is for discharging cooling air therefrom for cooling the splashplate. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic illustration of a gas turbine engine; 
       FIG. 2  is a cross-sectional view of a combustor used with the gas turbine engine shown in  FIG. 1 ; and 
       FIG. 3  is an enlarged view of a portion of the combustor shown in  FIG. 2  and taken along area  3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a schematic illustration of a gas turbine engine  10  including a fan assembly  12 , a high pressure compressor  14 , and a combustor  16 . Engine  10  also includes a high pressure turbine  18 , a low pressure turbine  20 , and a booster  22 . Fan assembly  12  includes an array of fan blades  24  extending radially outward from a rotor disc  26 . Engine  10  has an intake side  28  and an exhaust side  30 . In one embodiment, gas turbine engine  10  is a CF6-80 engine commercially available from General Electric Company, Cincinnati, Ohio. 
   In operation, air flows through fan assembly  12  and compressed air is supplied to high pressure compressor  14 . The highly compressed air is delivered to combustor  16 . Airflow from combustor  16  drives turbines  18  and  20 , and turbine  20  drives fan assembly  12 . 
     FIG. 2  is a cross-sectional view of combustor  16  used in gas turbine engine  10  (shown in  FIG. 1 ).  FIG. 3  is an enlarged view of a portion of combustor  16  taken along area  3  (shown in  FIG. 2 ). Combustor  16  includes an annular outer liner  40 , an annular inner liner  42 , and a domed end  44  that extends between outer and inner liners  40  and  42 , respectively. Outer liner  40  and inner liner  42  define a combustion chamber  46 . 
   Combustion chamber  46  is generally annular in shape and is disposed between liners  40  and  42 . Outer and inner liners  40  and  42  extend to a turbine nozzle  56  disposed downstream from combustor domed end  44 . In the exemplary embodiment, outer and inner liners  40  and  42  each include a plurality of panels  58  which include a series of steps  60 , each of which forms a distinct portion of combustor liners  40  and  42 . 
   In the exemplary embodiment, combustor domed end  44  includes an annular dome assembly  70  arranged in a single annular configuration. In another embodiment, combustor domed end  44  includes a dome assembly  70  arranged in a double annular configuration. In a further embodiment, combustor domed end  44  includes a dome assembly  70  arranged in a triple annular configuration. Combustor dome assembly  70  provides structural support to an upstream end  72  of combustor  16 , and dome assembly  70  includes a dome plate or spectacle plate  74  and a splashplate-flare cone assembly  76 . Splashplate-flare cone assembly  76  is unitary and includes a splashplate portion  77  and a flare cone portion  78 . In the exemplary embodiment, splashplate-flare cone assembly is fabricated using a casting process. 
   Combustor  16  is supplied fuel via a fuel injector  80  connected to a fuel source (not shown) and extending through combustor domed end  44 . More specifically, fuel injector  80  extends through dome assembly  70  and discharges fuel in a direction (not shown) that is substantially concentric with respect to a combustor center longitudinal axis of symmetry  82 . Combustor  16  also includes a fuel igniter  84  that extends into combustor  16  downstream from fuel injector  80 . 
   Combustor  16  also includes an annular air swirler  90  having an annular exit  92  that extends substantially symmetrically about center longitudinal axis of symmetry  82 . Exit  92  includes a radially outer surface  94  and a radially inwardly facing flow surface  96 . Annular air swirler  90  includes a radially outer surface  100  and a radially inwardly facing flow surface  102 . Exit flow surface  96  and air swirler flow surface  102  define an aft venturi channel or annulus  104  used for channeling a portion of air downstream therethrough. 
   Exit  92  includes an integrally formed outwardly extending radial flange portion  110 . Exit flange portion  110  includes an upstream surface  112  that extends from exit flow surface  96 , and a substantially parallel downstream surface  114  that is generally perpendicular to exit flow surface  96 . An integrally-formed radial flange portion  116  extends from air swirler  90 . Flange portion  116  includes an upstream surface  118 , and a downstream surface  120  that is substantially parallel to upstream surface  118  and extends from air swirler flow surface  102 . Air swirler flange surfaces  118  and  120  are substantially parallel to exit flange surfaces  112  and  114 , and are substantially perpendicular to air swirler flow surface  102 . 
   Exit  92  includes an integrally-formed coupling joint  130  that defines an attachment slot  134 . Splashplate-flare cone assembly  76  couples to exit  92  using coupling joint  130  and extends downstream from attachment slot  134 . More specifically, flare cone portion  78  includes a radially inner flow surface  140  and a radially outer surface  142 . When splashplate-flare cone assembly  76  is coupled to exit  92 , flare cone radially inner flow surface  140  is substantially co-planar with exit flow surface  96 . More specifically, flare cone inner flow surface  140  is divergent and extends downstream from coupling joint  130  to an elbow  146 , before extending divergently outward from elbow  146  to a trailing end  148  of flare cone portion  78 . 
   Flare cone outer surface  142  is substantially parallel to flare cone inner surface  140  between a leading edge  150  of flare cone portion  78  and elbow  146 . Flare cone outer surface  142  is divergent and extends radially outwardly from elbow  140 , such that in the exemplary embodiment, outer surface  142  is also substantially parallel to flare cone inner surface  140  between elbow  146  and flare cone trailing end  148 . 
   Splashplate portion  77  facilitates preventing hot combustion gases produced within combustor  16  from impinging upon combustor dome plate  74 , and includes a flange portion  160  and a divergent portion  162 . Flange portion  160  extends axially upstream from divergent portion  162  to a leading edge  166 , and is substantially parallel with combustor center longitudinal axis of symmetry  82 , such that flange portion leading edge  166  is upstream from flare cone leading edge  150 . 
   Splashplate divergent portion  162  extends radially outwardly and downstream from flange portion  160  to a trailing edge  168 . More specifically, divergent portion  162  is oriented generally parallel to flare cone portion  78  between flare cone trailing end  148  and flare cone elbow  146 , between flange portion  160  and a splashplate elbow  180 . Divergent portion  162  extends divergently outward from elbow  180  to trailing edge  168 . 
   Splashplate divergent portion  162  is spaced radially outwardly from flare cone portion  78  such that an annular gap  190  is defined therebetween. Specifically, gap  190  is defined between a radially inner surface  192  of divergent portion  162  and flare cone outer surface  142 . Gap  190  has a diameter D 1  that facilitates improving the producablity of splashplate-flare cone assembly  76 . 
   A plurality of circumferentially-spaced openings  200  are formed through splashplate-flare cone assembly  76 . Specifically, openings  200  extend through substantially axially through assembly  76  in a direction that is substantially parallel to centerline axis  82 , such that splashplate flange portion  160  is defined within assembly  76  by openings  200 . Openings  200  discharge cooling air therethrough at a reduced pressure for cooling of splashplate-flare cone assembly  76 . In one embodiment, the cooling air is compressor air. In the exemplary embodiment, openings  200  are formed using an electro-discharge machining (EDM) process. 
   During operation, cooling air is supplied to splashplate-flare cone assembly  76  through openings  200 . Openings  200  facilitate providing a continuous flow of cooling air to be discharged at a reduced air pressure for impingement cooling of flare cone portion  78 . The reduced air pressure facilitates improved cooling and backflow margin for the impingement cooling of flare cone portion  78 . Furthermore, the cooling air enhances convective heat transfer and facilitates reducing an operating temperature of flare cone portion  78 , which facilitates extending a useful life of flare cone portion  78 , while reducing a rate of oxidation formation of flare cone portion  78 . 
   Furthermore, as cooling air is discharged through openings  200 , splashplate divergent portion  162  is film cooled. More specifically, openings  200  supply splashplate divergent portion inner surface  192  with film cooling. Because openings  200  are spaced circumferentially through splashplate-flare cone assembly  76 , film cooling is directed along splashplate inner surface  192  substantially circumferentially around flare cone portion  78 . In addition, because openings  200  facilitate substantially uniform cooling flow, splashplate-flare cone assembly  76  facilitates optimizing film cooling while reducing mixing of the cooling air with combustion air, which thereby facilitates reducing an adverse effect of flare cooling on combustor emissions. 
   The above-described combustor system for a gas turbine engine is cost-effective and reliable. The combustor system includes a unitary splashplate-flare cone assembly that includes a plurality of formed cooling openings extending therethrough. Cooling air supplied through the openings facilitates substantial circumferential impingement cooling of the flare cone portion of the splashplate-flare cone assembly, and film cooling of the splashplate portion of the splashplate-flare cone assembly. As a result, the splashplate-flare cone assembly facilitates extending a useful life of the combustor in a reliable and cost-effective manner. 
   Exemplary embodiments of combustor assemblies are described above in detail. The combustor assemblies are not limited to the specific embodiments described herein, but rather, components of each assembly may be utilized independently and separately from other components described herein. For example, each splashplate-flare cone assembly component can also be used in combination with other combustors. 
   While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.