Abstract:
One embodiment of the present invention is a unique thrust augmented gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for thrust augmented 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. 61/428,760, filed Dec. 30, 2010, entitled Thrust Augmented Gas Turbine Engine, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to gas turbine engines, and more particularly, to gas turbine engine thrust augmentation systems. 
       BACKGROUND 
       [0003]    Gas turbine engines with thrust augmentation systems 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 having a unique thrust augmentation system. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for thrust augmented 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  is a cross section illustrating some aspects of a non-limiting example of a fluidic flameholder in accordance with an embodiment of the present invention. 
           [0008]      FIG. 3  illustrates some aspects of the fluidic flameholder of  FIG. 2  during fluid ejection from the fluidic flameholder. 
       
    
    
     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 , some aspects of a non-limiting example of a gas turbine engine  10  in accordance with an embodiment of the present invention are schematically depicted. In one form, gas turbine engine  10  is an aircraft propulsion power plant. In one form, gas turbine engine  10  is a multi-spool turbofan engine. In other embodiments, gas turbine engine  10  may take other forms, and may be, for example, a single spool turbojet engine. 
         [0011]    As a turbofan engine, gas turbine engine  10  includes a fan system  12 , a bypass duct  14 , a compressor system  16 , a diffuser  18 , a combustion system  20 , a turbine system  22 , a discharge duct  26  and a nozzle  28 . Bypass duct  14  and compressor system  16  are in fluid communication with fan system  12 . Diffuser  18  is in fluid communication with compressor system  16 . Combustion system  20  is in fluid communication with diffuser  18 . Turbine system  22  is in fluid communication with combustion system  20 , and is operative to discharge a core exhaust flow. In one form, combustion system  20  includes a combustion liner (not shown) that contains a continuous combustion process. In other embodiments, combustion system  20  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. 
         [0012]    Fan system  12  includes a fan rotor system  30 . In various embodiments, fan rotor system  30  includes one or more rotors (not shown) that are powered by turbine system  22 . Bypass duct  14  is operative to transmit a bypass flow generated by fan system  12  to nozzle  28 . Compressor system  16  includes a compressor rotor system  32 . In various embodiments, compressor rotor system  32  includes one or more rotors (not shown) that are powered by turbine system  22 . Each compressor rotor includes a plurality of compressor blades (not shown). Turbine system  22  includes a turbine rotor system  34 . In various embodiments, turbine rotor system  34  includes one or more rotors (not shown) operative to drive fan rotor system  30  and compressor rotor system  32 . Each turbine rotor includes a plurality of turbine blades (not shown). Turbine rotor system  34  is drivingly coupled to compressor rotor system  32  and fan rotor system  30  via a shafting system  36 . In various embodiments, shafting system  36  includes a plurality of shafts that may rotate at the same or different speeds and directions. In some embodiments, only a single shaft may be employed. Turbine system  22  is operative to discharge an engine  10  core exhaust flow to nozzle  28 . In one form, fan rotor system  30 , compressor rotor system  32 , turbine rotor system  34  and shafting system  36  rotate about an engine centerline  48 . In other embodiments, all or parts of fan rotor system  30 , compressor rotor system  32 , turbine rotor system  34  and shafting system  36  may rotate about one or more other axes of rotation in addition to, or in place of, engine centerline  48 . 
         [0013]    Turbine system  22  includes a turbine outlet  38  and a turbine outlet duct  40  extending from turbine outlet  38  toward nozzle  28 . Discharge duct  26  extends between turbine outlet duct  40  and an inlet portion of engine nozzle  28 . Discharge duct  26  is operative to direct bypass flow and core exhaust flow from a bypass duct discharge portion  42  and turbine outlet duct  40 , respectively, into nozzle system  28 . In some embodiments, discharge duct  26  may be considered a part of nozzle  28 . Nozzle  28  is in fluid communication with fan system  12  via bypass duct  14  and discharge duct  26 . Nozzle system  28  is in fluid communication with turbine system  22  via turbine outlet duct  40  and discharge duct  26 . Nozzle  28  is operative to receive the bypass flow from fan system  12 , to receive the core exhaust flow from turbine system  22 , and to discharge both via nozzle exit  28 A as an engine exhaust flow, i.e., a thrust-producing flow. 
         [0014]    During the operation of gas turbine engine  10 , air is drawn into the inlet of fan  12  and pressurized by fan  12 . Some of the air pressurized by fan  12  is directed into compressor system  16  as core flow, and some of the pressurized air is directed into bypass duct  14  as bypass flow, and is discharged into nozzle  28  via discharge duct  26 . Compressor system  16  further pressurizes the portion of the air received therein from fan  12 , which is then discharged into diffuser  18 . Diffuser  18  reduces the velocity of the pressurized air, and directs the diffused core airflow into combustion system  20 . Fuel is mixed with the pressurized air in combustion system  20 , which is then combusted. The hot gases exiting combustion system  20  are directed into turbine system  22 , which extracts energy in the form of mechanical shaft power sufficient to drive fan system  12  and compressor system  16  via shafting system  36 . The core flow exiting turbine system  22  is directed along between turbine outlet duct  42  and engine tail cone  44  into discharge duct  26 , along with the bypass flow from bypass duct  14 . Discharge duct  26  is configured to receive the bypass flow and the core flow, and to discharge both as an engine exhaust flow into nozzle  28 , e.g., for providing thrust, such as for aircraft propulsion. 
         [0015]    Engine  10  includes a thrust augmentation (afterburner) system  60  for providing increased thrust. Thrust augmentation system  60  includes a plurality of fluidic flameholders  62 . Thrust augmentation system  60  is operative to augment the thrust output of engine  10  by adding fuel to the exhaust flow of engine  10  downstream of turbine system  22 , and igniting the added fuel. In one form, the added fuel is ignited by igniters (not shown). In other embodiments, the fuel may be ignited via auto-ignition or via other means. The combustion of the added fuel adds heat to the exhaust flow, thereby increasing the volume of the exhaust gases and hence increasing the velocity of the exhaust flow exiting nozzle exit  28 A. Fluidic flameholders  62  are configured to hold flames during thrust augmentation operation, e.g., so that a continuous combustion process takes place. Flameholders  62  are referred to herein as “fluidic” flameholders because flameholders  62  employ a fluid to generate obstructions to exhaust flow, as opposed to a mechanical device forming an obstruction, such as in conventional flameholders. 
         [0016]    Referring to  FIGS. 2 and 3  in conjunction with  FIG. 1 , fluidic flameholders  62  are disposed downstream of turbine system  22  and upstream of nozzle exit  28 A. Fluidic flameholders  62  include a flowpath structure  64 , a fluid supply passage  66  and a plurality of fluid discharge openings  68 . In various embodiments, flowpath structure  64  may be disposed adjacent to the exhaust flow and/or may be disposed partially or fully within the exhaust flow. In one form, flowpath structure  64  extends radially inward of a turbine outlet duct  42 , and is positioned downstream of turbine system  22 , i.e., downstream of turbine outlet  38 . In other embodiments, flowpath structure  64  may be disposed in other locations, e.g., further downstream of turbine system  22 , e.g., in discharge duct  26  and/or nozzle  28 ; or further upstream toward turbine outlet  38 . In one form, flowpath structure  64  is configured as a strut that extends into the exhaust flow. In other embodiments, flowpath structure  64  may take one or more other forms. In one form, flowpath structure  64  extends from turbine outlet duct  42  to tailcone  44 . In other embodiments, flowpath structure  64  may extend only part way between turbine outlet duct  42  and tailcone  44 . In still other embodiments, flowpath structure  64  may be arranged otherwise, e.g., and may extend from other locations. 
         [0017]    Fluid supply passage  66  is in fluid communication with a pressurized fluid source (not shown), and is operative to supply fluid to fluid discharge openings  68 . Fluid discharge openings  68  are in fluid communication with fluid supply passage  66  on one end, and with the exhaust flow on the other end. Fluid discharge openings  68  are operative to eject the fluid received from fluid supply passage  66  into the exhaust flow. The number and/or shape of fluid discharge openings  68  may vary with the needs of the application. In one form, the fluid employed by fluidic flameholder  62  is liquid fuel. In other embodiments, other fluids, including gases and/or liquids, and including or not including fuel may be employed. In one form, fluid supply passage  66  and fluid discharge openings  68  are positioned at an upstream end  70  of flowpath structure  64 . In other embodiments, fluid supply passage  66  and/or one or more fluid supply openings  68  may be positioned at a downstream end  72  of flowpath structure  64  and/or other locations on flowpath structure  64  in addition to or in place of upstream end  70 . In one form, fluid discharge openings  68  are disposed on both sides of a centerline  74  of flowpath structure  64 , and are operative to eject fluid on both sides of centerline  74 . In other embodiments, one or more fluid discharge openings  68  may be positioned on only one side of centerline  74 , and may be operative to eject fluid on one or both sides of centerline  74 . In one form, the fluid discharge openings  68  are configured to eject the fluid with a velocity component in a direction  76  opposite the direction  78  of the exhaust flow. In other embodiments, fluid discharge openings  68  may be configured to eject the fluid in any suitable direction. 
         [0018]    Fluidic flameholder  62  is operative to generate an obstruction to the exhaust flow by ejecting the fluid from flowpath structure  64  via fluid discharge openings  68 , wherein the obstruction is configured to hold a flame during thrust augmentation operation of engine  10 . In one form, fluidic flameholder  62  is configured to generate the obstruction in the form of a low pressure area  80  downstream of fluid discharge openings  68  by ejecting fuel  82  into the exhaust flow. In other embodiments, the obstruction may take one or more other forms, e.g., a high pressure area. The obstruction or low pressure area  80  is configured to hold a flame during thrust augmentation operation. In one form, fluidic flameholder  62  is configured to generate the obstruction adjacent to downstream end  72  of flowpath structure  64 . In other embodiments, fluidic flameholder  62  may be configured to generate the obstruction in other locations near and/or spaced apart from flowpath structure  64 . The size, shape and location of the obstruction or low pressure area  80  may vary with the application, and may be determined, for example, using commercially available computational fluid dynamics analysis software. Parameters that affect the size and location of the obstruction or low pressure area include, for example and without limitation, the type, density and viscosity of the fluid ejected from fluidic flameholder  62 , as well as the pressure, temperature and velocity of the exhaust flow. 
         [0019]    Embodiments of the present invention include a gas turbine engine, comprising: a compressor; a combustor in fluid communication with the compressor; a turbine in fluid communication with the combustor and operative to discharge an exhaust flow; a nozzle in fluid communication with the turbine, wherein the nozzle includes a nozzle exit; and wherein the nozzle is operative to receive the exhaust flow from the turbine and to discharge the exhaust flow through the nozzle exit; and a thrust augmentation system, including a fluidic flameholder disposed downstream of the turbine and upstream of the nozzle exit, wherein the fluidic flameholder includes a flowpath structure disposed adjacent to the exhaust flow and/or at least partially within the exhaust flow; wherein the fluidic flameholder is operative to generate a low pressure area by ejecting a fluid from the flowpath structure into the exhaust flow, wherein the low pressure area is operative to hold a flame during thrust augmentation operation of the gas turbine engine. 
         [0020]    In a refinement, the flowpath structure includes a fluid supply passage for supplying the fluid and a fluid discharge opening for ejecting the fluid; wherein the fluid discharge opening is in fluid communication with both the fluid supply passage and the exhaust flow; wherein the fluid discharge opening is operative to eject the fluid into the exhaust flow. 
         [0021]    In another refinement, the flowpath structure is a strut extending at least partially into the exhaust flow. 
         [0022]    In yet another refinement, the ejected fluid is a liquid. 
         [0023]    In still another refinement, the ejected fluid includes fuel. 
         [0024]    In yet still another refinement, the ejected fluid is fuel. 
         [0025]    In a further refinement, the gas turbine engine further comprises a plurality of fluid discharge openings disposed in the flowpath structure and operative to eject the fluid into the exhaust flow. 
         [0026]    In a yet further refinement, the flowpath structure is configured as a strut having an upstream end and a downstream end; and wherein at least some of the fluid discharge openings are positioned at the upstream end of the strut. 
         [0027]    In a still further refinement, the strut has a downstream end, and wherein the low pressure area is disposed adjacent to the downstream end. 
         [0028]    Embodiments of the present invention include a gas turbine engine, comprising: a fan; a compressor in fluid communication with the fan; a combustor in fluid communication with the compressor; a turbine in fluid communication with the combustor and operative to discharge an exhaust flow; a bypass duct in fluid communication with the fan and operative to receive a bypass flow from the fan; a nozzle in fluid communication with the turbine and in fluid communication with the bypass duct, wherein the nozzle includes a nozzle exit; and wherein the nozzle is operative to receive the exhaust flow from the turbine and to receive the bypass flow from the fan and to discharge both through the nozzle exit; and a thrust augmentation system, including a fluidic flameholder disposed downstream of the turbine and upstream of the nozzle exit, wherein the fluidic flameholder includes a flowpath structure disposed adjacent to the exhaust flow and/or at least partially within the exhaust flow; wherein the fluidic flameholder is operative to generate an obstruction to the exhaust flow by ejecting a fluid from the flowpath structure into the exhaust flow, wherein the obstruction is operative to hold a flame during thrust augmentation operation of the gas turbine engine. 
         [0029]    In a refinement, the obstruction is in the form of a low pressure area operative to hold the flame during the thrust augmentation operation of the gas turbine engine. 
         [0030]    In another refinement, the flowpath structure includes a fluid discharge opening for ejecting the fluid. 
         [0031]    In yet another refinement, the obstruction is in the form of a low pressure area in the exhaust flow downstream of the fluid discharge opening. 
         [0032]    In still another refinement, the gas turbine engine further comprises a plurality of fluid discharge openings disposed in the flowpath structure and operative to eject the fluid into the exhaust flow. 
         [0033]    In yet still another refinement, the flowpath structure is configured as a strut having an upstream end and a downstream end; and wherein at least some of the fluid discharge openings are positioned at the upstream end of the strut. 
         [0034]    In a further refinement, the strut has a downstream end, and wherein the obstruction is disposed adjacent to the downstream end. 
         [0035]    In a yet further refinement, the flowpath structure has a centerline oriented in the direction of the exhaust flow; wherein at least one of the fluid discharge openings is oriented to eject the fluid on a first side of the centerline; and wherein at least another of the fluid discharge openings is oriented to eject the fluid on a second side of the centerline opposite the first side. 
         [0036]    In a still further refinement, at least one of the fluid discharge openings is configured to eject the fluid with a velocity component in a direction opposite to the direction of exhaust flow. 
         [0037]    Embodiments of the present invention include a gas turbine engine, comprising: a compressor; a combustor in fluid communication with the compressor; a turbine in fluid communication with the combustor and operative to discharge an exhaust flow; a nozzle in fluid communication with the turbine, wherein the nozzle includes a nozzle exit; and wherein the nozzle is operative to receive the exhaust flow from the turbine and to discharge the exhaust flow through the nozzle exit; and a thrust augmentation system, including means for holding a flame during thrust augmentation operation of the gas turbine engine, wherein the means for holding is disposed downstream of the turbine and upstream of the nozzle exit. 
         [0038]    In a refinement, the means for holding includes a fluid discharge opening configured to generate an obstruction to the exhaust flow by ejecting a fluid into the exhaust flow, wherein the obstruction is operative to hold the flame during thrust augmentation operation of the gas turbine engine. 
         [0039]    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.