Patent Publication Number: US-10788215-B2

Title: Fuel nozzle assembly with flange orifice

Description:
FIELD OF THE TECHNOLOGY 
     The present invention generally involves a combustor for a gas turbine. More specifically, the invention relates to a fuel nozzle assembly including an orifice disposed within a flange body of the fuel nozzle assembly. 
     BACKGROUND 
     During operation of a gas turbine engine, pressurized air from a compressor flows into a head end volume defined within the combustor. The pressurized air flows from the head end volume into an inlet to a corresponding premix passage of a respective fuel nozzle assembly. Fuel is injected into the flow of pressurized air within the premix passage where it mixes with the pressurized air so as to provide a fuel and air mixture to a combustion zone or chamber defined downstream from the fuel nozzle. The fuel and air mixture is burned in the combustion chamber to produce hot combustion gases. 
     The fuel may be supplied to the fuel nozzle(s) via one or more fuel circuits defined within an endcover which is fluidly coupled to a fuel supply. A pre-orifice insert or insert body is installed or seated within a respective fuel circuit of the endcover upstream from the fuel nozzle to meter the fuel flowing to the fuel nozzle. One drawback with placing the pre-orifice inserts strictly in the endcover is that it is necessary to flow test a complete endcover including the fuel nozzle assembly in order to test the flow therethrough and to create a flow matched set of complete endcover assemblies for a given gas turbine. 
     BRIEF DESCRIPTION OF THE TECHNOLOGY 
     Aspects and advantages are set forth below in the following description, or may be obvious from the description, or may be learned through practice. 
     One embodiment of the present disclosure is directed to a fuel nozzle assembly. The fuel nozzle assembly includes a flange body. The flange body includes a base portion that defines an aperture. The flange body is connected to a conduit. The flange body and the conduit define a fuel flow passage to a fuel plenum of the fuel nozzle assembly. The fuel nozzle assembly further includes an insert that is partially disposed within the aperture of the base portion. The insert includes an orifice disposed within the aperture of the base portion and a forward portion of the insert extends axially outwardly from the aperture. The orifice is in fluid communication with the fuel flow passage. 
     One embodiment of the present disclosure is directed to a combustor. The combustor includes an endcover defining a fuel circuit and a first fuel circuit outlet and a fuel nozzle assembly. The fuel nozzle assembly includes a plurality of nozzle segments which is annularly arranged about a center fuel nozzle. The plurality of nozzle segments includes a first nozzle segment. The first nozzle segment includes a flange body including a base portion which defines an aperture. The base portion is connected to the endcover and the flange body is connected to a conduit. The flange body and the conduit define a fuel flow passage to a fuel plenum of the first nozzle segment. The fuel nozzle assembly further includes an insert that is partially disposed within the aperture of the base portion of the flange body. The insert includes an orifice that is disposed within the aperture of the base portion and a forward portion of the insert extends axially outwardly from the aperture and into the first fuel circuit outlet. The orifice is in fluid communication with the fuel flow passage and provides for fluid communication from the first fuel circuit outlet to the fuel plenum of the first nozzle segment. 
     Another embodiment of the present disclosure is directed to a combustor. The combustor includes an endcover defining a fuel circuit and a first fuel circuit outlet and a fuel nozzle assembly. The fuel nozzle assembly includes a plurality of nozzle segments which is annularly arranged about a center fuel nozzle. The center fuel nozzle includes a flange body including a base portion which defines an aperture. The base portion is connected to the endcover and the flange body is connected to a conduit. The flange body and the conduit define a fuel flow passage to a fuel plenum of the center fuel nozzle. The fuel nozzle assembly further includes an insert that is partially disposed within the aperture of the base portion of the flange body. The insert includes an orifice that is disposed within the aperture of the base portion and a forward portion of the insert extends axially outwardly from the aperture and into the first fuel circuit outlet. The orifice is in fluid communication with the fuel flow passage and provides for fluid communication from the first fuel circuit outlet to the fuel plenum of the center fuel nozzle. 
     Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the of various embodiments, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which: 
         FIG. 1  is a functional block diagram of an exemplary gas turbine that may incorporate various embodiments of the present disclosure; 
         FIG. 2  is a simplified cross-section side view of an exemplary combustor as may incorporate various embodiments of the present disclosure; 
         FIG. 3  is an upstream view of an exemplary fuel nozzle assembly according to at least one embodiment of the present disclosure; 
         FIG. 4  is a cross-sectioned perspective view of an exemplary nozzle segment of the fuel nozzle assembly as shown in  FIG. 3 , according to at least one embodiment of the present disclosure; 
         FIG. 5  is an enlarged cross-sectional side view of a portion of the nozzle segment shown in  FIG. 4 , according to at least one embodiment of the present disclosure; 
         FIG. 6  is a cross-sectioned perspective view of an exemplary center or primary fuel nozzle of the fuel nozzle assembly as shown in  FIG. 3 , according to at least one embodiment of the present disclosure; and 
         FIG. 7  is an enlarged cross-sectional side view of a portion of the nozzle segment shown in  FIG. 6 , according to at least one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to present embodiments of the disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the disclosure. 
     As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. The term “radially” refers to the relative direction that is substantially perpendicular to an axial centerline of a particular component, the term “axially” refers to the relative direction that is substantially parallel and/or coaxially aligned to an axial centerline of a particular component, and the term “circumferentially” refers to the relative direction that extends around the axial centerline of a particular component. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Each example is provided by way of explanation, not limitation. In fact, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents. Although exemplary embodiments of the present disclosure will be described generally in the context of a combustor for a land based power generating gas turbine for purposes of illustration, one of ordinary skill in the art will readily appreciate that embodiments of the present disclosure may be applied to any style or type of combustor for a turbomachine and are not limited to combustors or combustion systems for land based power generating gas turbines unless specifically recited in the claims. 
     Referring now to the drawings,  FIG. 1  illustrates a schematic diagram of an exemplary gas turbine  10 . The gas turbine  10  generally includes a compressor  12 , at least one combustor  14  disposed downstream of the compressor  12  and a turbine  16  disposed downstream of the combustor  14 . Additionally, the gas turbine  10  may include one or more shafts  18  that couple the compressor  12  to the turbine  16 . 
     During operation, air  20  flows into the compressor  12  where the air  20  is progressively compressed, thus providing compressed or pressurized air  22  to the combustor  14 . At least a portion of the compressed air  22  is mixed with a fuel  24  within the combustor  14  and burned to produce combustion gases  26 . The combustion gases  26  flow from the combustor  14  into the turbine  16 , wherein energy (kinetic and/or thermal) is transferred from the combustion gases  26  to rotor blades (not shown), thus causing shaft  18  to rotate. The mechanical rotational energy may then be used for various purposes such as to power the compressor  12  and/or to generate electricity. The combustion gases  26  may then be exhausted from the gas turbine  10 . 
     As shown in  FIG. 2 , the combustor  14  may be at least partially surrounded by an outer casing  28  such as a compressor discharge casing. The outer casing  28  may at least partially define a high pressure plenum  30  that at least partially surrounds various components of the combustor  14 . The high pressure plenum  30  may be in fluid communication with the compressor  12  ( FIG. 1 ) so as to receive the compressed air  22  therefrom. An endcover  32  may be coupled to the outer casing  28 . One or more combustion liners or ducts  34  may at least partially define a combustion chamber or zone  36  for combusting the fuel-air mixture and/or may at least partially define a hot gas path through the combustor  14  for directing the combustion gases  26  towards an inlet  38  to the turbine  16 . In various embodiments, as shown in  FIG. 2 , the combustor  14  includes a fuel nozzle assembly  40 . 
       FIG. 3  provides an upstream view of an exemplary fuel nozzle assembly  40  according to at least one embodiment of the present disclosure. In particular embodiments, as shown in  FIG. 3 , the fuel nozzle assembly  40  includes a plurality of nozzle segments  100  annularly arranged about a fuel nozzle or primary fuel nozzle  200 . Although  FIG. 3  illustrates four individual nozzle segments  100 , the combustor  14  may include two or more nozzle segments  100  and is not limited to four nozzles segments  100  unless otherwise recited in the claims. In other embodiments, fuel nozzle assembly  40  may include just a single fuel nozzle  200 . 
       FIG. 4  provides a cross-sectioned perspective view of an exemplary nozzle segment  100  according to at least one embodiment of the present disclosure. In particular embodiments, as shown in  FIG. 4 , the nozzle segment  100  includes a first plate  102 , a second plate  104  axially spaced from the first plate  102 , and an outer band or sleeve  106  that extends axially between the first plate  102  and the second plate  104 . A fuel plenum  108  is defined between the first plate  102 , the second plate  104  and the outer band  106 . A plurality of premix tubes  110  extends through the first plate  102 , the fuel plenum  108  and the second plate  104 . Each premix tube  110  includes an inlet  112 , an outlet  114  and a premix flow passage  116  defined therebetween. The respective inlet  112  to one or more of the premix tubes  110  is in fluid communication with the high pressure plenum  30  ( FIG. 2 ). One or more of the premix tubes  110  may include at least one fuel port  118  disposed within and in fluid communication with the fuel plenum  108 . 
     In particular embodiments, as shown in  FIG. 4 , the nozzle segment  100  may be connected to the endcover  32  via a flange body  120 . A conduit or conduit assembly  42  extends from the flange body  120  to the first plate  102  of the nozzle segment  100 . The flange body  120  and/or the conduit  42  define(s) a fuel flow passage  122  between the endcover  32  and/or a fuel supply  44  and the fuel plenum  108 . 
       FIG. 5  provides an enlarged cross-sectional side view of a portion of the nozzle segment  100  shown in  FIG. 4 , according to at least one embodiment of the present disclosure. In various embodiments, as shown in  FIG. 5 , the flange body  120  defines an aperture  124  in a base portion  126  of the flange body  120 . The aperture  124  is aligned with a corresponding fuel circuit outlet or hole  46  at least partially defined within and/or by the endcover  32 . The fuel circuit outlet  46  is in fluid communication with a fuel circuit  48  at least partially defined within and/or by the endcover  32 . The fuel circuit  48  is fluidly coupled to the fuel supply  44 . 
     In various embodiments, an insert  128  is disposed or seated within the aperture  124 . In particular embodiments, the insert  128  is aligned or coaxially aligned with the fuel flow passage  122 . The insert  128  defines and/or includes an orifice  130  defined downstream from the fuel circuit outlet  46  and positioned within the base portion  126  of the flange body  120 . The orifice  130  provides for fluid communication from the fuel circuit  48  to the fuel passage  122 . In particular embodiments, a forward or upstream portion  132  of the insert  128  extends axially into the fuel circuit outlet  46 . In this manner, the forward portion  132  of the insert  128  forms a thermal shield between the flange body  120 , particularly the base portion  126 , and relatively cold fuel flowing through the insert  128  during operation, thereby reducing the potential for displacement of the insert  128  during thermal transients of the combustor  14 . 
       FIG. 6  provides a cross-sectioned perspective view of an exemplary primary fuel nozzle  200  according to at least one embodiment of the present disclosure. In particular embodiments, as shown in  FIG. 6 , the primary fuel nozzle  200  includes a first plate  202 , a second plate  204  axially spaced from the first plate  202 , and an outer band or sleeve  206  that extends axially between the first plate  202  and the second plate  204 . A fuel plenum  208  is defined between the first plate  202 , the second plate  204  and the outer band  206 . A plurality of premix tubes  210  extends through the first plate  202 , the fuel plenum  208  and the second plate  204 . Each premix tube  210  includes an inlet  212 , an outlet  214  and a premix flow passage  216  defined therebetween. The respective inlet  212  to one or more of the premix tubes  210  is in fluid communication with the high pressure plenum  30  ( FIG. 2 ). One or more of the premix tubes  210  may include at least one fuel port  218  disposed within and in fluid communication with the fuel plenum  208 . 
     In particular embodiments, as shown in  FIG. 6 , the primary fuel nozzle  200  may be connected to the endcover  32  via a flange body  220 . A conduit or conduit assembly  52  extends from the flange body  220  to the first plate  202  of the primary fuel nozzle  200 . The flange body  220  and/or the conduit  52  define(s) a fuel flow passage  222  between the endcover  32  and/or the fuel supply  44  and the fuel plenum  208 . 
       FIG. 7  provides an enlarged cross-sectional side view of a portion of the primary fuel nozzle  200  shown in  FIG. 6 , according to at least one embodiment of the present disclosure. In various embodiments, as shown in  FIG. 7 , the flange body  220  defines an aperture  224  in a base portion  226  of the flange body  220 . The aperture  224  is aligned with a corresponding fuel circuit outlet or hole  56  at least partially defined within and/or by the endcover  32 . The fuel circuit outlet  56  is in fluid communication with a fuel circuit  58  at least partially defined within and/or by the endcover  32 . The fuel circuit  58  is fluidly coupled to the fuel supply  44 . 
     In various embodiments, an insert  228  is disposed or seated within the aperture  224 . In particular embodiments, the insert  228  is radially offset from a centerline of the conduit  52  and/or the fuel flow passage  222 . The insert  228  defines and/or includes a first orifice  230  defined downstream from the fuel circuit outlet  56  and positioned within the base portion  226  of the flange body  220 . In particular embodiments, the insert  228  may include a second orifice  232  defined downstream from the first orifice  230 . In particular embodiments, the second orifice  232  may be defined along a side wall  234  of the insert  228 . 
     The flange body  220  may further define a flow passage  236  downstream from the insert  228  and upstream from the fuel passage  222 . The first orifice  230  and the second orifice  232  when present, provide for fluid communication from the fuel circuit  58  to the flow passage  235  and/or the fuel passage  222 . In particular embodiments, a forward or upstream portion  236  of the insert  228  extends axially into the fuel circuit outlet  56 . In this manner, the forward portion  236  of the insert  228  forms a thermal shield between the flange body  220 , particularly the base portion  226 , and relatively cold fuel flowing through the insert  228  during operation, thereby reducing the potential for displacement of the insert  228  during thermal transients of the combustor  14 . 
     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 include 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 language of the claims.