Abstract:
One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique fuel injection system for a gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and fuel injection systems for gas turbine engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims benefit of U.S. Provisional Patent Application No. 61/427,726, filed Dec. 28, 2010, entitled GAS TURBINE ENGINE AND FUEL INJECTION SYSTEM, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to gas turbine engines, and more particularly, to fuel injection systems for gas turbine engines. 
       BACKGROUND 
       [0003]    Gas turbine engines and fuel injection systems for gas turbine engines remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology. 
       SUMMARY 
       [0004]    One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique fuel injection system for a gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and fuel injection systems for gas turbine engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0006]      FIG. 1  schematically illustrates some aspects of a non-limiting example of a gas turbine engine in accordance with an embodiment of the present invention. 
           [0007]      FIG. 2  depicts some aspects of a non-limiting example of combustion system in accordance with an embodiment of the present invention. 
           [0008]      FIG. 3  depicts some aspects of a non-limiting example of a fuel injection system in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the invention is intended by the illustration and description of certain embodiments of the invention. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present invention. Further, any other applications of the principles of the invention, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the invention pertains, are contemplated as being within the scope of the present invention. 
         [0010]    Referring to the drawings, and in particular  FIG. 1 , a non-limiting example of a gas turbine engine  10  in accordance with an embodiment of the present invention is depicted. In one form, engine  10  is an aircraft propulsion power plant. In other embodiments, engine  10  may be a land-based or marine engine. In one form, engine  10  is a multi-spool turbofan engine. In other embodiments, engine  10  may be a single or multi-spool turbofan, turboshaft, turbojet, turboprop gas turbine or combined cycle engine. 
         [0011]    Gas turbine engine  10  includes a fan system  12 , a compressor system  14 , a diffuser  16 , a combustion system  18  and a turbine system  20 . Compressor system  14  is in fluid communication with fan system  12 . Diffuser  16  is in fluid communication with compressor system  14 . Combustion system  18  is fluidly disposed between compressor system  14  and turbine system  20 . Fan system  12  includes a fan rotor system  22 . In various embodiments, fan rotor system  22  includes one or more rotors (not shown) that are powered by turbine system  20  and operative to pressurize air. Compressor system  14  includes a compressor rotor system  24 . In various embodiments, compressor rotor system  24  includes one or more rotors (not shown) that are powered by turbine system  20  and operative to further pressurize air received from fan system  12 . Turbine system  20  includes a turbine rotor system  26 . In various embodiments, turbine rotor system  26  includes one or more rotors (not shown) operative to drive fan rotor system  22  and compressor rotor system  24 . Turbine rotor system  26  is driving coupled to compressor rotor system  24  and fan rotor system  22  via a shafting system  28 . In various embodiments, shafting system  28  includes a plurality of shafts that may rotate at the same or different speeds and in the same or different directions. In some embodiments, only a single shaft may be employed. 
         [0012]    During the operation of gas turbine engine  10 , air is drawn into the inlet of fan system  12  and pressurized by fan system  12 . Some of the air pressurized by fan system  12  is directed into compressor system  14 , and the balance is directed into a bypass duct (not shown) for providing a component of the thrust output by gas turbine engine  10 . Compressor system  14  further pressurizes the air received from fan system  12 , which is then discharged in to diffuser  16 . Diffuser  16  reduces the velocity of the pressurized air, and directs the diffused airflow into combustion system  18 . Fuel is mixed with the pressurized air in combustion system  18 , which is then combusted. In one form, combustion system  18  includes a combustion liner (not shown) that contains a continuous combustion process. In other embodiments, combustion system  18  may take other forms, and may be, for example, a wave rotor combustion system, a rotary valve combustion system, or a slinger combustion system, and may employ deflagration and/or detonation combustion processes. The hot gases exiting combustion system  18  are directed into turbine system  20 , which extracts energy in the form of mechanical shaft power to drive fan system  12  and compressor system  14  via shafting system  28 . The hot gases exiting turbine system  20  are directed into a nozzle (not shown), and provide a component of the thrust output by gas turbine engine  10 . 
         [0013]    Referring to  FIG. 2 , combustion system  18  includes a combustion liner  30  and a fuel injection system  32 . Combustion liner  30  is disposed in a combustor case  34 . Combustion liner  30  is operative to contain combustion processes during the operation of engine  10 . Fuel injection system  32  is operative to inject fuel into combustion liner  30 . In particular, fuel injection system  32  is operative to inject a fuel/air mixture into combustion liner  30 , which is ignited by an igniter (not shown) to form a combustion process  36  that adds heat to the air discharged by compressor system  14 . The heated air is then discharged by combustion system  18  into turbine system  20 . 
         [0014]    Referring to  FIG. 3  in conjunction with  FIG. 2 , fuel injection system  32  includes a pilot injection module  38  and a main injection module  40 . Main injection module  40  is disposed concentrically around pilot injection module  38 , i.e., radially outward of pilot injection module  38 . Pilot injection module  38 , disposed radially inward of main injection module  40 , is configured inject a pilot fuel flow  42  to generate a pilot combustion process  44 . Main injection module  40  is configured to inject a main fuel flow  46  to generate a main combustion process  48  disposed around pilot combustion process  44 . In one form, pilot injection module  38  and main injection module  40  are independently operable. During low power operation of engine  10 , e.g., including ground idle and flight idle conditions, pilot injection module  38  is employed. Main injection module  40  is employed during high power engine  10  operation, e.g., including take-off and cruise thrust. Some operating regimes include the use of both pilot injection module  38  and main injection module  40 , e.g., during transition from idle or other low power conditions to higher power conditions. In some embodiments, both main injection module  40  and pilot injection module  38  may be employed to inject fuel into combustion liner  30  during high power engine  10  operation. In other embodiments, only main injection module  40  is employed during high power engine  10  operation. 
         [0015]    Pilot injection module  38  is fluidly coupled to a fuel supply line  50 . Main injection module  40  is fluidly coupled to a fuel supply line  52 . Fuel supply lines  50  and  52  are fluidly independent of each other, that is, one supply line may be pressurized to supply fuel to the corresponding injection module independent of the other fuel supply line. In one form, fuel injection system  32  is configured to selectively control fuel delivery (including fuel pressure) to fuel supply lines  50  and  52 , providing independent control of pilot injection module  38  and main injection module  40  to selectively supply fuel to one or both of pilot injection module  38  and main injection module  40 . In other embodiments, pilot injection module  38  and main injection module  40  may be fluidly coupled to a common fuel supply line, and may be selectively and independently operable via other means. In still other embodiments, pilot injection module  38  and main injection module  40  may not be independently operable as such. In one form, pilot injection module  38  is optimized for operation in low engine  10  power conditions, and main injection module  40  is optimized for operation in high engine  10  power conditions. In other embodiments, pilot injection module  38  and main injection module  40  may be optimized for operation at other engine  10  power conditions. 
         [0016]    Pilot injection module  38  includes a pilot nozzle  54 , a pilot swirler  56  and a discharge nozzle  58 . Pilot nozzle  54  is in fluid communication with fuel supply line  50 . Pilot nozzle  54  is operative to inject fuel into combustion liner  30 . In one form, pilot nozzle  54  is a pressure swirl atomizer. In other embodiments, pilot nozzle  54  may take other forms. In one form, pilot swirler  56  surrounds pilot nozzle  54 . In other embodiments, pilot swirler  56  may be arranged in other locations and orientations. In one form, pilot swirler  56  includes a plurality of turning vanes  60  configured to induce swirl into airflow passing through pilot swirler  56 . In other embodiments, other means for inducing swirl may be employed, e.g., air injection and/or fuel injection ports configured to induce swirl. 
         [0017]    The swirling pilot airflow from pilot swirler  56  mixes with the fuel sprayed by pilot nozzle  54 . In one form, pilot injection module  38  is configured to mix pilot fuel spray and air before injection into the combustion zone. The swirl induced by pilot swirler  56  enhances the mixing of fuel and air for pilot injection module  38 , e.g., relative to systems that do not employ swirlers. The amount of swirl may vary with the application. The fuel discharged from pilot nozzle  54  and the air passing through pilot swirler  56  are discharged into combustion liner  30  via discharge nozzle  58 . In one form, discharge nozzle  58  is circular in shape. In other embodiments, discharge nozzle  58  may be shaped differently. 
         [0018]    Main injection module  40  includes a main fuel injector  62 , a main swirler  64 , a deswirler  66  and a discharge nozzle  68 . Main fuel injector  62  is in fluid communication with fuel supply line  52 . Main fuel injector  62  is operative to inject fuel for mixing with air and combustion in combustion liner  30 . In one form, main fuel injector  62  is configured to indirectly inject fuel into combustion liner  30 , via swirler  64 . In other embodiments, main fuel injector  62  may be configured to directly inject fuel into combustion liner  30 , e.g., similar to pilot nozzle  54 . 
         [0019]    Main fuel injector  62  includes a fuel manifold  70  and plurality of main fuel nozzles  72 . In one form, manifold  70  is a distribution annulus formed in main fuel injector  62  and disposed radially outward of and circumferentially around pilot injection module  38 . In other embodiments, fuel manifold  70  may take other forms. Fuel manifold  70  is in fluid communication with fuel supply line  52 . Fuel nozzles  72  are in fluid communication fuel manifold  70 . In one form, fuel nozzles  72  are plain-jet nozzles. In other embodiments, other nozzle types may be employed in addition to or in place of plain-jet nozzles. In one form, nozzles  72  extend outward in a radial direction from manifold  70 . In the example depicted in  FIG. 3 , nozzles  72  extend both radially outward and aft. In other embodiments, nozzles  72  may extend in other directions in addition to or in place of radial and/or aft directions. In one form, nozzles  72  are configured to discharge fuel radially outward, that is, having a radially outward flow direction component. In the example depicted in  FIG. 3 , nozzles  72  are configured to discharge fuel both radially outward and aft. In other embodiments, nozzles  72  may be configured to discharge fuel in other directions in addition to or in place of radial and/or aft directions. In some embodiments, some nozzles  72  may be configured to discharge fuel in one direction, whereas others may be configured to discharge fuel in one or more other directions. 
         [0020]    Main swirler  64  is configured to induce swirl in order to enhance the mixing of fuel and air for main fuel injector  62 . In one form, main swirler  64  is an axial swirler. In other embodiments, main swirler  64  may take one or more other forms. In one form, main swirler  64  includes a plurality of turning vanes  74  configured to induce swirl into airflow passing through main swirler  64 . In other embodiments, other means for inducing swirl may be employed, e.g., air injection and/or fuel injection ports configured to induce swirl. In one form, nozzles  72  include discharge openings  76  disposed in main swirler  64 , and are operative to inject fuel directly into main swirler  64 . In other embodiments, some or all of discharge openings  76  may be disposed elsewhere. 
         [0021]    Deswirler  66  is configured to reduce swirl induced by main swirler  64 . In one form, deswirler  66  is disposed radially outward of main swirler  64 . In other embodiments, deswirler  66  may be positioned in other locations and orientations. In one form, deswirler  66  includes a non-swirling air passage. In a particular form, deswirler  66  is configured to form an annular non-swirling air stream disposed around the swirling fuel and air discharged by main swirler  64 , to reduce the exit swirl angle of the fuel and air discharged through discharge nozzle  68 . In other embodiments, other means for reducing swirl may be employed. 
         [0022]    Discharge nozzle  68  is operative to discharge the air fuel mixture, generated by main injection module  40 , into combustion liner  30 . In one form, discharge nozzle  68  is a converging nozzle. In other embodiments, discharge nozzle  68  may take other forms. In one form, discharge nozzle  68  includes contraction ramps  80  and  82  extending to and forming a throat  84 . In one form, ramps  80  and  82  are conical. In other embodiments, ramps  80  and  82  may take other forms. In some embodiments, only a single contraction ramp may be employed. The air fuel mixture generated by main injection module  40  is injected into combustion liner  30  via discharge nozzle  68 . In one form, discharge nozzle  68  is annular in shape, extending concentrically around pilot injection module  38  and discharge nozzle  58 . In other embodiments, discharge nozzle  68  may take other forms. In one form, ramps  80  and  82  are configured to direct the air fuel mixture from main injection module  40  in a radially outward direction, that is, in a direction having a radially outward component from pilot injection module  38 . In one form, discharge nozzle  68  includes a plurality of air injection openings  86  spaced apart circumferentially around the periphery of discharge nozzle  68 , located aft of deswirler  66  and forward of contraction ramp  80 . Air injection openings  86  are positioned to injection air into main injection module  40  upstream of discharge nozzle  68 . In other embodiments, air injection openings may be disposed in other locations. Air injection openings  86  may take any convenient shape. Some embodiments may not include air injection openings  86 . 
         [0023]    Disposed between pilot nozzle  54  and main injection module  40  is a separating member  88 . In one form, separating member  88  is configured as a heat shield to shield pilot nozzle  54  from heat generated during the combustion of fuel. 
         [0024]    Embodiments of the present invention include a gas turbine engine, comprising: a compressor system; a turbine system; and a combustion system fluidly disposed between the compressor system and the turbine system, the combustion system including a combustion liner and a fuel injection system operative to inject fuel into the combustion liner, wherein the fuel injection system includes: a pilot injection module having a pilot nozzle and a pilot swirler for the pilot nozzle, wherein the pilot swirler is operative to induce swirl to enhance mixing of fuel and air for the pilot injection module; and a main injection module disposed radially outward of the pilot injection module, wherein the main injection module includes a main fuel injector; a main swirler; and a deswirler, wherein the main fuel injector includes a plurality of nozzles operative to discharge fuel radially outward; wherein the main swirler is operative to induce swirl to enhance mixing of fuel and air for the main fuel injector; and wherein the deswirler is operative to reduce swirl induced by the main swirler. 
         [0025]    In a refinement, the deswirler is located radially outward of the main swirler. 
         [0026]    In another refinement, the main fuel injector includes a plurality of plain-jet nozzles. 
         [0027]    In yet another refinement, the engine further comprises a main fuel manifold, wherein at least one of the plain-jet nozzles extends outward in a radial direction from the main fuel manifold. 
         [0028]    In still another refinement, at least one of the plain-jet nozzles has a discharge opening disposed in the main swirler. 
         [0029]    In yet still another refinement, the engine further comprises a first fuel supply line; and a second fuel supply line that is fluidly independent of the first fuel supply line, wherein the pilot nozzle is fluidly coupled to the first fuel supply line; and wherein the main fuel injector is fluidly coupled to the second fuel supply line. 
         [0030]    In a further refinement, the fuel injection system is configured to selectively supply fuel to one or both of the pilot injection module and the main injection module. 
         [0031]    Embodiments of the present invention include a fuel injection system for a gas turbine engine, comprising: a main injection module including a plurality of plain-jet nozzles; a main swirler; and a deswirler; wherein at least one of the plain-jet nozzles is operative to discharge fuel radially outward; wherein the main swirler is operative to induce swirl to enhance mixing of fuel and air for the main injection module; and wherein the deswirler is operative to reduce swirl induced by the main swirler; and a pilot injection module disposed radially inward of the main injection module, wherein the pilot injection module includes a pilot nozzle and a pilot swirler for the pilot nozzle, wherein the pilot swirler is operative to induce swirl to enhance mixing of fuel and air for the pilot injection module. 
         [0032]    In a refinement, the deswirler includes a non-swirling air passage. 
         [0033]    In another refinement, the main injection module includes an annular discharge nozzle for discharging a fuel air mixture. 
         [0034]    In yet another refinement, the main injection module includes a discharge nozzle for discharging a fuel air mixture, further comprising a plurality of air injection openings positioned to inject air into the main injection module upstream of the discharge nozzle. 
         [0035]    In still another refinement, the system further comprises a ramp configured to direct an air fuel mixture from the main injection module in a radially outward direction. 
         [0036]    In yet still another refinement, the ramp is conical. 
         [0037]    In a further refinement, the system further comprises a separating member disposed around the pilot nozzle and positioned between the pilot nozzle and the main injection module. 
         [0038]    In a yet further refinement, the separating member is configured to shield the pilot nozzle from combustion heat. 
         [0039]    In a still further refinement, the at least one of the plain-jet nozzles is configured to inject fuel directly into the main swirler. 
         [0040]    Embodiments of the present invention include a fuel injection system for a gas turbine engine, comprising: a pilot injection module having a pilot nozzle operative to produce a pilot combustion zone; and a main injection module having a fuel distribution manifold; a plurality of main nozzles extending from the fuel distribution manifold for injecting fuel; a main swirler; and a deswirler, wherein the main swirler is operative to induce swirl into fuel and air in the main injection module; and wherein the deswirler is operative to reduce swirl induced by the main swirler. 
         [0041]    In a refinement, the system further comprises a heat shield disposed around the pilot injection module and positioned between the pilot injection module and the main injection module. 
         [0042]    In another refinement, the main nozzles are plain-jet nozzles oriented with a directional component extending radially outward of the pilot nozzle. 
         [0043]    In still another refinement, the main injection module is configured to produce a main combustion zone disposed radially outward of the pilot combustion zone. 
         [0044]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.