Patent Publication Number: US-8984888-B2

Title: Fuel injection assembly for use in turbine engines and method of assembling same

Description:
FEDERAL RESEARCH STATEMENT 
     This invention was made with Government support under Contract No. DE-FC26-05NT42643, awarded by the Department of Energy (DOE), and the Government has certain rights in this invention. 
    
    
     BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein generally relates to turbine engines and, more particularly, to a fuel injection assembly for use in a turbine engine. 
     At least some known turbine engines are used in cogeneration facilities and power plants. Such engines may have high specific work and power per unit mass flow requirements. To increase the operating efficiency, at least some known turbine engines, such as gas turbine engines, operate with increased combustion temperatures. In at least some known gas turbine engines, engine efficiency increases as combustion gas temperatures increase. 
     However, operating with higher temperatures may also increase the generation of polluting emissions, such as oxides of nitrogen (NO X ). In an attempt to reduce the generation of such emissions, at least some known turbine engines include improved combustion system designs. For example, many combustion systems may use premixing technology that includes tube assemblies or micro-mixers that facilitate mixing substances, such as diluents, gases, and/or air with fuel to generate a fuel mixture for combustion. 
     However, the benefits of such combustion systems may be limited. Each tube assembly or micro-mixer has a substantially large recirculation region within its center area or large blockage area. More specifically, the combustion product that is recirculating in the center area interacts with the combustible mixture within each of the tubes in the tube assemblies that are located within the center area. As a result, the temperature within the recirculation region is substantially higher than other areas of the tube assembly or micro-mixer. The high temperature results in a reduced margin of a flashback and/or a flameholding in the tubes that are located in the recirculation region. Increased temperatures may also increase the wear of the combustor and its associated components, and/or may shorten the useful life of the combustion system. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, a fuel injection assembly for use in a turbine engine is provided. The fuel injection assembly includes a plurality of tube assemblies, wherein each of the tube assemblies include an upstream portion and a downstream portion. Each of the tube assemblies include a plurality of tubes that extend from the upstream portion to the downstream portion or from the upstream portion through the downstream portion. At least one injection system is coupled to at least one tube assembly of the plurality of tube assemblies. The injection system includes a fluid supply member that extends from a fluid source to the downstream portion of the tube assembly. The fluid supply member includes a first end portion located in the downstream portion of the tube assembly, wherein the first end portion has at least one first opening for channeling fluid through the tube assembly to facilitate reducing a temperature therein. 
     In another embodiment, a turbine engine is provided. The turbine engine includes a compressor and a combustion assembly coupled downstream from the compressor. The combustion assembly includes at least one combustor that includes at least one fuel injection assembly. The fuel injection assembly includes a plurality of tube assemblies wherein each of the tube assemblies includes an upstream portion and a downstream portion. Each of the tube assemblies include a plurality of tubes that extend from the upstream portion to the downstream portion or from the upstream portion through the downstream portion. At least one injection system is coupled to at least one tube assembly of the plurality of tube assemblies. The injection system includes a fluid supply member that extends from a fluid source to the downstream portion of the tube assembly. The fluid supply member includes a first end portion located in the downstream portion of the tube assembly, wherein the first end portion has at least one first opening for channeling fluid to the tube assembly to facilitate reducing a temperature therein. 
     In yet another embodiment, a method of assembling a fuel injection assembly for use with a turbine engine is provided. A plurality of tube assemblies are coupled within a combustor, wherein each of the tube assemblies include an upstream portion and a downstream portion. Each of the plurality of tube assemblies includes a plurality of tubes that extend from the upstream portion to the downstream portion or from the upstream portion through the downstream portion. At least one injection system is coupled to at least one tube assembly of the plurality of tube assemblies. The injection system includes a fluid supply member that extends from a fluid source to the downstream portion of the tube assembly. The fluid supply member includes a first end portion located in the downstream portion of the tube assembly, wherein the first end portion includes at least one first opening for channeling fluid to the tube assembly to facilitate reducing a temperature therein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional view of an exemplary turbine engine; 
         FIG. 2  is a schematic cross-sectional view of an exemplary fuel injection assembly that may be used with the turbine engine shown in  FIG. 1  and taken along area  2 ; 
         FIG. 3  is a schematic cross-sectional view of the fuel injection assembly shown in  FIG. 2  and taken along line  3 - 3 ; 
         FIG. 4  is a schematic cross-sectional view of an alternative fuel injection assembly and also taken along line  3 - 3  (shown in  FIG. 2 ); 
         FIG. 5  is an enlarged schematic cross-sectional view of a portion of an exemplary injection system that may be used with the fuel injection assembly shown in  FIG. 2  and taken along area  5 ; 
         FIG. 6  is an enlarged schematic cross-sectional view of a portion of an alternative injection system that may be used with the fuel injection assembly shown in  FIG. 2  and taken along area  6 ; 
         FIG. 7  is an enlarged schematic cross-sectional view of a portion of another alternative injection system that may be used with the fuel injection assembly shown in  FIG. 2  and taken along area  7 ; 
         FIG. 8  is an enlarged schematic cross-sectional view of a portion of an exemplary fluid supply member that may be used with the injection system shown in  FIG. 5  and taken along area  8 ; 
         FIG. 9  is an enlarged schematic cross-sectional view of a portion of an alternative fluid supply member that may be used with the injection system shown in  FIG. 5  and taken along area  8 ; and 
         FIG. 10  is an enlarged schematic cross-sectional view of a portion of an alternative fluid supply member that may be used with the injection system shown in  FIG. 5  and taken along area  8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The exemplary apparatus, systems, and methods described herein overcome at least some known disadvantages associated with at least some known combustion systems of turbine engines that operate with higher temperatures. The embodiments described herein provide a fuel injection assembly that may be used with turbine engines to facilitate substantially reducing the temperature within the combustor. More specifically, the fuel injection assembly includes a plurality of tube assemblies, wherein each of the tube assemblies include an upstream portion and a downstream portion. Each of the tube assemblies include a plurality of tubes that extend from the upstream portion to the downstream portion or from the upstream portion through the downstream portion. At least one injection system is coupled to at least one tube assembly of the plurality of tube assemblies. The injection system includes a fluid supply member that extends from a fluid source to the downstream portion of the tube assembly. The fluid supply member includes a first end portion located in the downstream portion of the tube assembly, wherein the first end portion has at least one first opening for channeling fluid through the tube assembly to facilitate reducing a temperature therein. More specifically, channeling the fluid to at least one of the tube assemblies facilitates reducing the temperature in the center area of tube assembly and of the tubes positioned within the center area, and reducing the probability of or preventing flashbacks and/or flameholdings within the tube. 
       FIG. 1  is a schematic cross-sectional view of an exemplary turbine engine  100 . More specifically, turbine engine  100  is a gas turbine engine. While the exemplary embodiment includes a gas turbine engine, the present invention is not limited to any one particular engine, and one of ordinary skill in the art will appreciate that the current invention may be used in connection with other turbine engines. 
     Moreover, in the exemplary embodiment, turbine engine  100  includes an intake section  112 , a compressor section  114  coupled downstream from intake section  112 , a combustor section  116  coupled downstream from compressor section  114 , a turbine section  118  coupled downstream from combustor section  116 , and an exhaust section  120 . Turbine section  118  is coupled to compressor section  114  via a rotor shaft  122 . In the exemplary embodiment, combustor section  116  includes a plurality of combustors  124 . Combustor section  116  is coupled to compressor section  114  such that each combustor  124  is positioned in flow communication with the compressor section  114 . A fuel injection assembly  126  is coupled within each combustor  124 . Turbine section  118  is coupled to compressor section  114  and to a load  128  such as, but not limited to, an electrical generator and/or a mechanical drive application. In the exemplary embodiment, each compressor section  114  and turbine section  118  includes at least one rotor disk assembly  130  that is coupled to a rotor shaft  122  to form a rotor assembly  132 . 
     During operation, intake section  112  channels air towards compressor section  114  wherein the air is compressed to a higher pressure and temperature prior to being discharged towards combustor section  116 . The compressed air is mixed with fuel and other fluids that are provided by each fuel injection assembly  126  and ignited to generate combustion gases that are channeled towards turbine section  118 . More specifically, each fuel injection assembly  126  injects fuel, such as natural gas and/or fuel oil, air, and/or diluents, such as Nitrogen gas (N 2 ) in respective combustors  124 , and into the air flow. The fuel mixture is ignited to generate high temperature combustion gases that are channeled towards turbine section  118 . Turbine section  118  converts the thermal energy from the gas stream to mechanical rotational energy, as the combustion gases impart rotational energy to turbine section  118  and to rotor assembly  132 . By having each fuel injection assembly  126  inject the fuel with air and/or diluents in respective combustors  124 , the temperature may be reduced within each combustor  124 . 
       FIG. 2  is a cross-sectional view of a portion of fuel injection assembly  126  and taken along area  2  (shown in  FIG. 1 ). In the exemplary embodiment, fuel injection assembly  126  includes a plurality of tube assemblies  202 , wherein each tube assembly  202  includes an upstream portion  156  and a downstream portion  158 . Each tube assembly  202  includes a plurality of tubes  204  that extend from upstream portion  156  to downstream portion  158 . In the exemplary embodiment, tube assemblies  202  are fuel injection nozzles that are each substantially axially coupled within combustor  124  (shown in  FIG. 1 ). Tube assemblies  202  may be formed integrally within combustor  124  or tube assemblies  202  may be coupled to combustor  124 . In the exemplary embodiment, each tube  204  discharges a mixture of fuel, air, and other fluids that are channeled through a passage (not shown) within each tube  204 . 
     Fuel injection assembly  126  also includes at least one injection system  206 . More specifically, in the exemplary embodiment, each tube assembly  202  is coupled to one injection system  206 . Injection system  206 , in the exemplary embodiment, includes a fuel delivery pipe  208  and a fluid supply member  210  that is positioned at least partially within fuel delivery pipe  208 . Alternatively, fluid supply member  210  may be positioned in any other location with respect to fuel delivery pipe  208 , such as adjacent to fuel delivery pipe  208 , and enables fuel injection assembly  126  and/or turbine engine  100  (shown in  FIG. 1 ) to function as described herein. 
     In the exemplary embodiment, fluid supply member  210  extends from a fluid source  212  and extends through an end cover  213  of combustor  124  to downstream portion  158  of tube assembly  202 . Alternatively, fluid supply member  210  may extend from a downstream surface  211  of end cover  213  or from a middle portion  215  of fluid supply member to downstream portion  158  of tube assembly  202 . Fluid supply member  210 , in the exemplary embodiment, includes a first end portion  214  coupled within tube assembly  202 , a middle portion  215 , and a second end portion  216  that is coupled to fluid source  212 . Fluid source  212 , in the exemplary embodiment, may include air, an inert gas, and/or a diluent, such as Nitrogen gas (N 2 ), Carbon Dioxide (CO 2 ), and/or steam. First end portion  214 , in the exemplary embodiment, includes at least one first opening (not shown in  FIG. 2 ) for channeling fluid to tube assembly  202 . 
     Similarly, fuel delivery pipe  208  includes a first end portion  220  that is coupled to tube assembly  202 , a middle portion  221 , and a second end portion  222  that is coupled to a fuel source (not shown). In the exemplary embodiment, middle portion  221  of fuel delivery pipe  208  has a substantially cylindrical shape and is sized such that fluid supply member  210  may be positioned therein. Middle portion  215  of fluid supply member  210  also has a substantially cylindrical shape and is sized to be positioned within fuel delivery pipe  208 . Alternatively, fuel delivery pipe  208  and fluid supply member  210 , and any portions of fuel delivery pipe  208  and fluid supply member  210  may have any other shape and/or size that enables fuel injection assembly  126  and/or turbine engine  100  to function as described herein. 
       FIG. 3  is a schematic cross-sectional view of fuel injection assembly  126  taken along line  3 - 3  (shown in  FIG. 2 ).  FIG. 4  is a schematic cross-sectional view of an alternative fuel injection assembly  250  that may be used with turbine engine  100  taken along line  3 - 3  (shown in  FIG. 2 ). Referring to  FIG. 3 , in the exemplary embodiment, tube assemblies  202  include a central tube assembly  270 , wherein each tube assembly  202  and  270  are substantially circular. Alternatively, tube assemblies  202  and  270  may be any other shape that enables tube assemblies  202  and  270  to function as described herein. 
     Moreover, the tubes  204  contained within each tube assembly  202  and  270  are spaced circumferentially therein. In the exemplary embodiment, each tube assembly  202  and  270  can have any number of tubes  204  that enables each tube assembly  202  and  270  to function as described herein. In the exemplary embodiment, tube assemblies  202  are spaced circumferentially about central tube assembly  270 . 
     Alternatively, tube assemblies  202  may be arranged in any orientation that enables tube assemblies  202  to function as described herein. For example, as illustrated in  FIG. 4 , fuel injection assembly  250  includes a central tube assembly  271  and outer tube assemblies  272 . In the exemplary embodiment, central tube assembly  271  is substantially circular and outer tube assemblies  272  have a substantially truncated-pie sector shape. Moreover, outer tube assemblies  272  each extend radially outwardly from central tube assembly  271 . 
     Moreover, referring to  FIG. 3 , each tube assembly  202  is coupled to one injection system  206 . More specifically, injection system  206  is positioned within a center region or area  300  of each tube assembly  202 . Accordingly, fuel delivery pipe  208  and fluid supply member  210  are each positioned in the center area  300  within each tube assembly  202  such that fluid supply member  210  is coupled in flow communication between fluid source  212  (shown in  FIG. 2 ) and tube assembly  202 , allowing for fluid to be discharged into at least one first opening (not shown in  FIGS. 3 and 4 ). Similarly, in  FIG. 4 , one injection system  206  is coupled to each of the central tube assembly  271  and outer tube assemblies  272 . More specifically, each injection system  206  is positioned in a center region or area  278  of each tube assembly  271  and  272 . Accordingly, fuel delivery pipe  208  and fluid supply member  210  are each positioned in the center area  278  within each tube assembly  271  and  272 . 
       FIG. 5  is an enlarged schematic cross-sectional view of injection system  206  with tube assembly  202  and taken along area  5  (shown in  FIG. 2 ).  FIG. 6  is an enlarged schematic cross-sectional view of a portion of an alternative injection system  280  and taken along area  6  (shown in  FIG. 2 ).  FIG. 7  is an enlarged schematic cross-sectional view of a portion of another alternative injection system  282  and taken along area  7  (shown in  FIG. 2 ).  FIG. 8  is an enlarged schematic cross-sectional view of a portion of fluid supply member  210  taken along area  8  (shown in  FIG. 5 ). 
     Referring to  FIGS. 5 and 8 , in the exemplary embodiment, injection system  206  is coupled approximately to center region or area  300  of tube assembly  202 . In the exemplary embodiment, center area  300  is a recirculatation region wherein any fluids being channeled to tube assembly  202  is injected and disperses or blows recirculating hot combustion product and/or deforms a recirculation region (not shown), and is recirculated, as shown by arrows  301 , such that the fluid remains within center area  300 . Fuel delivery pipe  208  and fluid supply member  210  positioned therein are each coupled within center area  300 . 
     A channel  302  is defined within fuel delivery pipe  208 . More specifically, in the exemplary embodiment, channel  302  is defined within fuel delivery pipe  208 , and provides a flow path, as shown by arrows  303 , for the flow of fuel therein. Then the fuel is injected through at least an aperture  307  into each tube  204  and then mixes with air in the tube  204 . A channel  304  is also defined within fluid supply member  210  and provides a flow path, as shown by arrows  305 , for the flow of fluid therein. Alternatively, fuel delivery pipe  208  and/or fluid supply member  210  may each have a channel that provides any other type of flow path and that enables fuel injection assembly  126  and/or turbine engine  100  to function as described herein. In the exemplary embodiment, fluid is channeled from second end portion  216  (shown in  FIG. 2 ) of fuel delivery pipe. 
     Alternatively, as illustrated in  FIG. 6 , fluid may be channeled from a middle portion  281  of a fluid supply member  283 . More specifically, fluid from fluid source  212  (shown in  FIG. 2 ) may channel fluid directly to at least one opening  284  of fluid supply member  283  that is located within middle portion  281 . 
     Alternatively, as illustrated in  FIG. 7 , fluid may be channeled from a first end portion  285  of a fluid supply member  286 . More specifically, fluid from fluid source  212  (shown in  FIG. 2 ) may channel fluid directly to at least one opening  287  of fluid supply member  286  that is located within first end portion  285 . 
     Referring to  FIGS. 5 and 8 , in the exemplary embodiment, first end portion  214  of fluid supply member  210  includes an upstream surface  306  and a downstream surface  308 . First end portion  214  also includes at least one opening  310  that extends from channel  304 . In the exemplary embodiment, upstream  306  and downstream surfaces  308  have a curved shape for facilitating fluid flow within tube assembly  202 . More specifically, upstream  306  and downstream surfaces  308  have a substantially concave shape. Alternatively, upstream  306  and downstream surfaces  308  may have a different shape, such as a convex shape that enables fuel injection assembly  126  and/or turbine engine  100  to function as described herein. 
     During operation, fuel is channeled through fuel delivery pipe  208  and supplied to tube assembly  202 , wherein the fuel is mixed with air to form a combustible mixture in tubes  204 . Hot combustion product is recirculated within center area  300  is in contact with tubes  204  that located within center area  300  and also interacts with some combustible mixture from tubes  204 . As a result, center area  300  and innermost and/or second row of tubes  204  arranged within center area  300  have an increased temperature as compared to other areas of tube assembly  202 . Such an increase in temperature results in a reduced margin of a flameholding and/or flashback in such rows of tubes  204  located within center area  300 . 
     To improve the flameholding and/or flashback margin, other fluids are channeled to tube assembly  202 . More specifically, in the exemplary embodiment, when fuel is supplied to tube assembly  202 , fluids, such as air and/or diluents are channeled through fluid supply member  210  and are also supplied to tube assembly  202 . More specifically, fluid is channeled from fluid source  212  (shown in  FIG. 2 ) through fluid supply member  210  to first end portion  214 . The fluid is channeled through opening  310  and supplied to tube assembly  202 . The fluid deforms the recirculating flow pattern in the center area  300  and some of the fluid is then recirculated to center area  300 , wherein the fluid facilitates disrupting the interaction between the combustion product circulating in center area  300  and the combustible mixture from tubes  204  and facilitates preventing the contact of hot combustion product to tube outlets (not shown). By substantially reducing such interactions, the temperature of tube assembly  202  is reduced, and the useful life of tube assembly  202  may be lengthened, as well as the useful life of combustor  124  (shown in  FIG. 1 ). 
       FIG. 9  illustrates a portion of an alternative fluid supply member  400  that may be used with injection system  206  (shown in  FIGS. 2 and 5 ) in place of fluid supply member  210  (shown in  FIGS. 2 ,  5 , and  8 ) and taken along area  8  (shown in  FIG. 5 ). Fluid supply member  400 , in the exemplary embodiment, includes a first end portion  414  coupled within tube assembly  202  (shown in  FIGS. 2 and 3 ), a middle portion  415 , and a second end portion (not shown) coupled to fluid source  212  (shown in  FIG. 2 ). Middle portion  415  of fluid supply member  400  has a substantially cylindrical shape and is sized to be positioned within fuel delivery pipe  208  (shown in  FIGS. 2 and 3 ). A channel  420  is defined within fluid supply member  400  and provides a flow path, as shown by arrows  424 , for the flow of fluid therein. 
     In the exemplary embodiment, first end portion  414  includes an upstream surface  426  and a downstream surface  428 . An opening  430  extends from channel  420 . In the exemplary embodiment, upstream  426  and downstream surfaces  428  have a substantially planar surface for facilitating fluid flow within tube assembly  202 . 
     During operation, when fuel is supplied to tube assembly  202 , fluids, such as air and/or diluents are also channeled through fluid supply member  400  and are also supplied to tube assembly  202 . More specifically, fluid is channeled from fluid source  212  through fluid supply member  400  to first end portion  414 . The fluid is channeled through opening  430  and supplied to tube assembly  202 . 
       FIG. 10  illustrates a portion of an alternative fluid supply member  500  that may be used with injection system  206  (shown in  FIGS. 2 and 5 ) in place of fluid supply member  210  (shown in  FIGS. 2 ,  5 , and  8 ) and taken along area  8  (shown in  FIG. 5 ). Fluid supply member  500 , in the exemplary embodiment, includes a first end portion  514  coupled within tube assembly  202  (shown in  FIGS. 2 and 3 ), a middle portion  515 , and a second end portion (not shown) coupled to fluid source  212  (shown in  FIG. 2 ). Middle portion  515  of fluid supply member  500  has a substantially cylindrical shape and is sized to be positioned within fuel delivery pipe  208  (shown in  FIGS. 2 and 3 ). A channel  520  is defined within fluid supply member  500 and provides a flow path, as shown by arrows  524 , for the flow of fluid therein. 
     In the exemplary embodiment, first end portion  514  includes an upstream portion  530  coupled to a downstream portion  532  such that a channel  534  is defined therebetween. At least one first opening  538  is defined within and extends radially through downstream portion  532  for facilitating fluid flow to tube assembly  202 . At least one second opening  536  is defined within and extends through upstream portion  530  for facilitating fluid flow to channel  534 . In the exemplary embodiment, downstream portion includes six first openings  538  in cross-section view of fluid supply member  500 . Alternatively, downstream portion may have any number of openings. In the exemplary embodiment, downstream portion  532  also has a first surface  550  and a second surface  552 . First  550  and second surface  552  have a substantially planar surface for facilitating fluid flow within tube assembly  202 . 
     During operation, when fuel is supplied to tube assembly  202 , fluids, such as air and/or diluents are channeled through fluid supply member  500  and are also supplied to tube assembly  202 . More specifically, fluid is channeled from fluid source  212  through fluid supply member  500  to first end portion  514 . The fluid is channeled through second opening  536  and supplied to channel  534 . Fluid is then channeled to first openings  538  and supplied to tube assembly  202 . 
     As compared to known apparatus and systems that are used with turbine engines, the above-described fuel injection assembly may be used with turbine engines to facilitate reducing the temperature generated within fuel injection assembly. More specifically, the fuel injection assembly includes a plurality of tube assemblies, wherein each of the tube assemblies include an upstream portion and a downstream portion. Each of the tube assemblies include a plurality of tubes that extend from the upstream portion to the downstream portion or from the upstream portion through the downstream portion. At least one injection system is coupled to at least one tube assembly of the plurality of tube assemblies. The injection system includes a fluid supply member that extends from a fluid source to the downstream portion of the tube assembly. The fluid supply member includes a first end portion located in the downstream portion of the tube assembly, wherein the first end portion has at least one first opening for channeling fluid through the tube assembly to facilitate reducing a temperature therein. More specifically, channeling the fluid to at least one of the tube assemblies facilitates reducing the temperature in the center area of tube assembly and of the tubes positioned within the center area, and reducing the probability of or preventing flashbacks and/or flameholdings within the tube. 
     Exemplary embodiments of a fuel injection assembly and method of assembling same are described above in detail. The fuel injection assembly and method of assembling same are not limited to the specific embodiments described herein, but rather, components of the fuel injection assembly and/or steps of the injection assembly may be utilized independently and separately from other components and/or steps described herein. For example, the fuel injection assembly may also be used in combination with other machines and methods, and is not limited to practice with only a turbine engine as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other systems. 
     Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     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 language of the claims.