Patent Publication Number: US-2011072823-A1

Title: Gas turbine engine fuel injector

Description:
BACKGROUND 
     This application relates generally to dispersing fuel within the combustor section of a gas turbine engine. 
     Gas turbine engines are known and typically include multiple sections, such as an inlet section, a compression section, a combustor section, a turbine section, and an exhaust nozzle section. The inlet section moves air into the engine. The air is compressed in the compression section. The compressed air is mixed with fuel and is combusted in combustion areas within the combustor section. The products of the combustion expand to rotatably drive the engine. 
     The combustor section of the gas turbine engine typically includes injectors that deliver fuel and air to the combustion areas. Poorly mixed fuel and air, or a high fuel to air ratio, can result in fuel-rich pockets within the combustion areas, which can undesirably increase smoke emissions from the engine. Atomizing fuel delivered to the combustion areas desirably reduces smoke emissions, especially in Rich-Quench-Lean (RQL) combustors. Atomizing the fuel reduces the fuel to small particles. 
     Some prior art injectors atomize the fuel delivered to the combustors using swirlers, such as vanes mounted to the injector. As known, the swirler-typed injectors often cannot typically be used in gas turbine engines that need to meet more stringent cold high altitude starting requirements. Referring to Prior Art FIG. 1, a prior art injector 100 discharges fuel through a single tube 114 into the combustor area. Air moves through a single passage 118 that surrounds the tube 114. As known, these prior art injectors limit of the shear layer area between the air and the fuel resulting in non-uniform fuel atomization and poor fuel/air mixing, especially near the centerline of the passage 118. Such a design can undesirably increase the smoke and nitrous oxide emissions of the engine. 
     SUMMARY 
     An example gas turbine engine fuel injector nozzle assembly includes a nozzle tip secured relative to a combustion area within a gas turbine engine. The nozzle establishes a plurality of first apertures that are configured to communicate a fuel to the combustion area. The nozzle establishes at least one second aperture that is configured to communicate a fluid to the combustion area. The fluid is different than the fuel. The fluid is air in one example. 
     An example gas turbine engine fuel injector assembly includes a housing mountable relative to a combustion area within a gas turbine engine, a nozzle tip secured to the housing and establishing an axis, and a fuel conduit configured to communicate a fuel through the housing to the nozzle tip. First apertures in the nozzle tip are circumferentially distributed about the axis and are each configured to communicate some of the fuel from the fuel conduit to the combustion area. At least one of the housing or the nozzle tip establishes a second aperture that is configured to communicate a fluid that is different than the fuel to the combustion area. The fluid is air in one example. 
     An example method of providing fuel to a combustion area within a gas turbine engine includes communicating a fuel through a first aperture in a nozzle tip to a combustion area in a gas turbine engine. The nozzle tip establishes an axis. The method also includes influencing fuel moving from the nozzle tip using a fluid directed through a second aperture in the nozzle tip. The fluid is different than the fuel. A portion of the second aperture is radially closer to the axis than the first aperture. The fluid is air in one example. 
     These and other features of the example disclosure can be best understood from the following specification and drawings, the following of which is a brief description: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a sectional view of a prior art injector. 
         FIG. 2  is a schematic view of an example gas turbine engine. 
         FIG. 3  shows partial sectional view of the combustor section of the  FIG. 2  engine. 
         FIG. 4  shows a perspective view of the  FIG. 3  injector with some portions removed. 
         FIG. 5  shows a sectional view through line  5 - 5  of the  FIG. 3  injector. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  schematically illustrates an example gas turbine engine  10  including (in serial flow communication) an inlet section  14 , a centrifugal compressor  1 , a combustor section  26 , a turbine wheel  30 , and a turbine exhaust  34 . The gas turbine engine  10  is circumferentially disposed about an engine centerline X 1 . During operation, air is pulled into the gas turbine engine  10  by the inlet section  14 , pressurized by the compressor  18 , mixed with fuel, and burned in the combustor section  26 . The turbines wheel  30  extracts energy from the hot combustion gases flowing from the combustor section  26 . 
     In a radial design, the turbine wheel  30  utilizes the extracted energy from the hot combustion gases to power the centrifugal compressor  18 . The examples described in this disclosure are not limited to the radial turbine type auxiliary power units described and may be used in other architectures, such as a single-spool axial design, two-spool axial design, a three-spool axial design. That is, there are various types of engines that could benefit from the examples disclosed herein, which are not limited to the radial turbine design shown. 
     Referring to  FIGS. 3-5  with continuing reference to  FIG. 2 , in the combustor section  26 , an example injector  50  communicates fuel and air to a combustion area  54 . An ignitor  58  ignites the mixture. The resulting hot combustion gasses G move from the combustion area  54  to the turbine wheel  30  of the engine  10 . Fuel, in this example, is a type of ignitable fluid. Example fuels are JETA, JETB, JP4, JPS, JP8, diesel fuels and bio-fuels. 
     The example injector  50  includes a fuel conduit  62  and a nozzle tip  66 . Fuel moves from a fuel supply  70 , through the fuel conduit  62 , through the nozzle tip  66 , to the combustion area  54 . The nozzle tip  66  is mounted in a housing  68  of the injector  50 . 
     In this example, at least some of the fuel moves through a plurality of slots  74  in the nozzle tip  66 . The slots  74 , a type of aperture, are circumferentially arranged about an axis A in an array. The example slots  74  are radially extending. That is, the radial dimension of the slots  74  is greater than the circumferential dimension. This example includes three slots  74  positioned every 120 degrees about the axis A. Internal channels  78 , within the nozzle tip  66 , communicate fuel from the fuel conduit  62  to each of the plurality of slots  74 . 
     In this example, at least some of the fuel also moves to the combustion area  54  through an aperture  78  in the nozzle tip  66 . The example aperture  78  is aligned with the axis A and has a circular cross-sectional profile. 
     The nozzle tip  66  establishes a plurality of apertures  82  that communicate air, another type of fluid, from an air supply  86  to the combustion area  54 . In this example, an array of the apertures  82  is circumferentially arranged about the axis. Each of the apertures  82  has a triangular cross-sectional profile. This example includes three apertures  82  positioned every 120 degrees about the axis A. 
     The slots  74  and the apertures  82  alternate in this example. That is, one of the slots  74  is positioned circumferentially between two of the apertures  82 , and one of the apertures  82  is positioned circumferentially between two of the slots  74 . The apertures  82  also extend radially closer to the axis A than the slots  74 . The array of the slots  74  is thus circumferentially offset from the array of the apertures  82 . 
     In this example, air communicates though the apertures  82  to atomize fuel exiting the nozzle tip  66  through the slots  74 . In another example, air communicates though other apertures in the housing, such as apertures (not shown) at locations  90 , to atomize the fuel exiting the nozzle tip  66  though the slots  74 . Air communicates through the other apertures instead of, or in addition to, the apertures  82 . 
     The example nozzle tip  66  is brazed or welded to the housing  68 . Other examples secure the nozzle tip  66  to the housing  68  using other methods of attachment. The nozzle tip  66  is IN625 steel in this example. 
     Features of the disclosed examples include communicating fuel to a combustion area through multiple apertures in a nozzle tip to facilitate atomizing the fuel using air. 
     Although a preferred embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.