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

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims benefit of U.S. Provisional Patent Application No. 61/427,599, filed Dec. 28, 2010, entitled GAS TURBINE ENGINE WITH BYPASS MIXER, which is incorporated herein by reference. 
    
    
     GOVERNMENT RIGHTS 
     The present application was made with the United States government support under Contract No. F33615-03-D-2357, awarded by the United States Air Force. The United States government may have certain rights in the present application. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to gas turbine engines, and more particularly, gas turbine engines with bypass mixers. 
     BACKGROUND 
     Gas turbine engines that produce bypass flow 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 
     One embodiment of the present invention is a gas turbine engine with a bypass mixer. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and bypass mixers. 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 
       The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
         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. 
         FIGS. 2A and 2B  schematically illustrate some aspects of a non-limiting example of bypass mixer for a gas turbine engine in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     Referring to the drawings, and in particular  FIG. 1 , a non-limiting example of some aspects of a gas turbine engine  10  in accordance with an embodiment of the present invention is schematically depicted. In one form, gas turbine engine  10  is an aircraft propulsion power plant. In other embodiments, gas turbine engine  10  may be a land-based engine or marine engine. In one form, gas turbine engine  10  is a multi-spool turbofan engine. In other embodiments, gas turbine engine  10  may take other forms. 
     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 bypass mixer  24 , 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 fluidly disposed between compressor system  16  and turbine system  22 . In one form, combustion system  20  includes a combustion liner (not shown) that contains a continuous combustion process during the operation of engine  10 . 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. 
     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 . 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 . 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 flow to nozzle  28 . 
     Discharge duct  26  extends between a bypass duct discharge portion  38 , a turbine discharge portion  40  and engine nozzle  28 . Discharge duct  26  is operative to direct bypass flow and core flow from bypass duct discharge portion  38  and turbine discharge portion  40 , respectively, into nozzle system  28 . In some embodiments, discharge duct  26  may be considered a part of nozzle  28 . Nozzle  28  in fluid communication with fan system  12  and turbine system  22 . Nozzle  28  is operative to receive the bypass flow from fan system  12  via bypass duct  14 , and to receive the core flow from turbine system  22 , and to discharge both as an engine exhaust flow, e.g., a thrust-producing flow. 
     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, which is discharged into nozzle  28  via bypass mixer  24  and discharge duct  26 . Compressor system  16  further pressurizes the portion of the air received therein from fan  12 , which is then discharged by compressor system  16  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 , and 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 to drive fan system  12  and compressor system  16  via shafting system  36 . The core flow exiting turbine system  22  is directed along an engine tail cone  42  and 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, e.g., for providing thrust, such as for aircraft propulsion. 
     In some situations, it is desirable to control the ratio between the bypass flow and the core flow supplied to nozzle  28 , e.g., based on engine  10  operating parameters and output requirements. For example, an engine  10  high thrust operating mode may employ a lower bypass ratio than an engine  10  high specific fuel consumption (SFC) operating mode. Bypass mixer  24  is configured to vary the bypass ratio by increasing or decreasing the bypass flow area exposed to discharge duct  26  and nozzle  28 . 
     Referring to  FIGS. 2A and 2B , some aspects of a non-limiting example of bypass mixer  24  in accordance with an embodiment of the present invention is schematically illustrated. Bypass mixer  24  is a variable area bypass mixer, and is configured to vary the bypass ratio of engine  10 , i.e., to vary a ratio of the bypass flow to the core flow that is directed into nozzle  28  to form the engine exhaust flow. Bypass mixer  24  includes a sled  44  and a plurality of actuators  46  (only a single actuator  46  is illustrated). Actuators  46  are coupled to sled  44 , and are configured to translate sled  44 . In one form, each actuator  46  is an electro-mechanical actuator, e.g., a linear actuator. In other embodiments, actuators  46  may be one or more other types of actuators, including linear or rotary pneumatic and hydraulic actuator types in addition to or in place of electro-mechanical actuators. In one form, the plurality of actuators  46  are spaced apart circumferentially at different locations around engine  10 . In other embodiments, other arrangements may be employed, including the use of a single actuator  46 . 
     Actuator  46  is configured to translate sled  44  between a first position yielding a maximum bypass flow area of bypass duct  14  that is exposed to engine nozzle  28 ; and a second position yielding a minimum bypass flow area of bypass duct  14  exposed to engine nozzle  28 . Maximum, minimum and intermediate flow areas may vary with the needs of the application. In one form, sled  44  is configured to translate parallel to an engine centerline  48 . In particular, sled  44  is configured to translate in a forward direction  50  and in an aft direction  52 . In other embodiments, sled  44  may be configured to translate in other directions in addition to or in place of forward direction  50  and aft direction  52 . In one form, sled  44  is disposed within bypass duct  14 . In other embodiments, sled  44  may be disposed in other locations internal and/or external to engine  10 . 
     In one form, sled  44  is piloted by a guide member  54 . Guide member  54  forms a part of an outer core flowpath wall  56 . An inner core flowpath wall  58  is formed by tail cone  42 . In other embodiments, outer core flowpath wall  56  and inner core flowpath wall  58  may be formed by other structures in addition to or in place of guide member  54  and tail cone  42 , respectively. Outer core flowpath wall  56  and inner core flowpath wall  58  define a core flowpath  60  in turbine discharge portion  40  of turbine system  22 . Core flowpath  60  channels core flow toward discharge duct  26  and nozzle  28 . 
     Bypass duct  14  includes an outer flowpath wall  64  and an inner bypass flowpath wall  66 . Outer flowpath wall  64  and inner bypass flowpath wall  66  define a bypass flowpath  68  that channels bypass flow toward nozzle  28 . In one form, actuator  46  is disposed in bypass flowpath  68  in bypass duct  14 . In other embodiments, actuator  46  may be disposed in other engine  10  locations. In one form, a forward portion  70  of actuator  46  is mounted on a fixed portion  72  of inner bypass flowpath wall  66  via a hinge joint  74 . In other embodiments, forward portion  70  may be mounted in other locations, e.g., such as outer flowpath wall  64 , via the same or a different mounting arrangement. In some embodiments, a hinge joint may not be employed. In one form, an aft portion  76  of actuator  46  is mounted on sled  44  via a hinge joint  74 . In other embodiments, aft portion  76  may be mounted in other locations and/or otherwise coupled to sled  44 . 
     Sled  44  is configured as a translatable flowpath wall structure. Sled  44  is disposed between core flowpath  60  and bypass flowpath  68 . In one form, sled  44  is configured as a ring structure, e.g., for embodiments wherein bypass flowpath  68  is annular in shape at locations adjacent to sled  44 . In other embodiments, sled  44  may take other forms. Outer bypass flowpath wall  64  includes a throat portion  78 . Throat portion  78  extends radially inward, e.g., toward core flowpath  60 . Throat portion  78  forms a part of bypass duct discharge portion  38 . Sled  44  is positioned adjacent to throat portion  78  and upstream of discharge duct  26 . In other embodiments, sled  44  may be positioned in other locations. 
     Sled  44  includes an inner surface  80  that forms a portion of outer core flowpath wall  56 . Sled  44  also includes an outer surface  82  that forms a portion of inner bypass flowpath wall  66 . Outer surface  82  of sled  44  is disposed opposite to outer bypass flowpath wall  64 . Outer surface  82  may have any suitable shape. Inner surface  80  of sled  44  is disposed opposite to outer core flowpath wall  56 . Inner surface  80  may have any suitable shape. In one form, throat portion  78  of outer bypass flowpath wall  64  and outer surface  82  of sled  44  form a converging nozzle  84  operative to discharge the bypass flow into discharge duct  26  and nozzle  28 . In other embodiments, a converging nozzle may not be formed as between outer bypass flowpath wall  64  and outer surface  82  of sled  44 . 
     Actuator  46  is configured to translate sled  44  between a first position yielding a maximum bypass flow area A 1  and a second position yielding a minimum bypass flow area A 2 . In the depiction of  FIGS. 2A and 2B , the bypass flow areas A 1  and A 2  have a shape corresponding to the frustum of a cone. In other embodiments, other shapes may be employed. In some embodiments, bypass mixer  24  is configured for a non-zero minimum area A 2 , whereas in other embodiments, bypass mixer  24  may be configured to provide a minimum area A 2  of zero. During the operation of engine  10 , actuator  46  is employed to selectively translate sled  44  in direction  50  and/or direction  52  in order to obtain a desired flow area for discharging the bypass flow into discharge duct  26 , thereby obtaining a desired bypass ratio. 
     Embodiments of the present invention include a gas turbine engine, comprising: a fan system operative to generate a bypass flow; a bypass duct in fluid communication with the fan system and operative to transmit the bypass flow from the fan system; a compressor system in fluid communication with the fan system; a combustion system in fluid communication with the compressor system; a turbine system in fluid communication with the combustion system and operative to discharge an engine core flow; an engine nozzle in fluid communication with the fan system and the turbine system, wherein the engine nozzle is operative to receive the bypass flow and the core flow and to discharge both as an engine exhaust flow; and a variable area bypass mixer configured to vary a ratio of the bypass flow to the core flow directed into the engine nozzle to form the engine exhaust flow, wherein the variable area bypass mixer includes a translatable sled; and wherein the variable area bypass mixer is configured to translate the sled between a first position yielding a maximum bypass flow area of the bypass duct exposed to the engine nozzle and a second position yielding a minimum bypass flow area of the bypass duct exposed to the engine nozzle. 
     In a refinement, the bypass mixer includes an actuator coupled to the sled; and wherein the actuator is configured to translate the sled between the first position and the second position. 
     In another refinement, the actuator is an electro-mechanical actuator. 
     In yet another refinement, the sled is disposed within the bypass duct. 
     In still another refinement, the bypass duct includes an outer bypass flowpath wall; and wherein the sled forms at least a portion of an inner bypass flowpath wall disposed opposite to the outer bypass flowpath wall. 
     In yet still another refinement, the turbine system includes a discharge portion having an inner core flowpath wall; and wherein the sled forms at least a portion of an outer core flowpath wall. 
     In a further refinement, the bypass duct includes an outer bypass flowpath wall; wherein the turbine system includes a discharge portion having an inner core flowpath wall; and wherein the sled is configured as a ring structure disposed between the outer bypass flowpath wall and the inner core flowpath wall. 
     In a still further refinement, the bypass duct includes an outer bypass flowpath wall; and wherein the sled is configured to form, in conjunction with the outer bypass flowpath wall, a converging nozzle operative to discharge the bypass flow into the engine nozzle. 
     Embodiments include a gas turbine engine, comprising: a fan system operative to generate a bypass flow; a bypass duct in fluid communication with the fan system and operative to transmit the bypass flow from the fan system, wherein the bypass duct includes a bypass duct discharge portion operative to discharge the bypass flow; a compressor system in fluid communication with the fan system; a combustion system in fluid communication with the compressor system; a turbine system in fluid communication with the combustion system and operative to discharge an engine core flow, wherein the turbine system includes a turbine system discharge portion operative to discharge the core flow; a discharge duct in fluid communication with the turbine system discharge portion and the bypass duct discharge portion, wherein the discharge duct is configured to receive the bypass flow and the core flow, and to discharge an engine exhaust flow formed of the bypass flow and the core flow; and a translatable flowpath wall structure configured to translate in a first direction to increase a flow area of the bypass duct discharge portion exposed to the discharge duct, and to translate in a second direction to decrease the flow area. 
     In a refinement, the translatable flowpath wall structure is disposed between the bypass duct discharge portion and the turbine system discharge portion. 
     In another refinement, the engine further comprises an actuator coupled to the flowpath wall structure and operative to translate the flowpath wall structure in the first direction and in the second direction. 
     In yet another refinement, the actuator is disposed in the bypass duct. 
     In still another refinement, the bypass duct includes an outer bypass flowpath wall having a throat portion; and wherein the throat portion is shaped to extend radially inward toward the translatable flowpath wall structure. 
     In yet still another refinement, the translatable flowpath wall structure is disposed within the bypass duct. 
     In a further refinement, the bypass duct includes an outer bypass flowpath wall; and wherein the translatable flowpath wall structure is configured to form, in conjunction with the outer bypass flowpath wall, a converging nozzle operative to discharge the bypass flow into the discharge duct. 
     In a yet further refinement, the translatable flowpath wall structure is operative to translate between a first position yielding a maximum bypass flow area and a second position yielding a minimum bypass flow area. 
     In a still further refinement, the translatable flowpath wall structure is disposed upstream of the discharge duct. 
     In a yet still further refinement, the translatable flowpath wall structure is positioned aft of the turbine system. 
     Embodiments include a gas turbine engine, comprising: a fan system operative to generate a bypass flow; a bypass duct in fluid communication with the fan system and operative to transmit the bypass flow from the fan system, wherein the bypass duct includes a bypass duct discharge portion operative to discharge the bypass flow; a compressor system in fluid communication with the fan system; a combustion system in fluid communication with the compressor system; a turbine system in fluid communication with the combustion system and operative to discharge an engine core flow, wherein the turbine system includes a turbine system discharge portion operative to discharge the core flow; a discharge duct in fluid communication with the turbine system discharge portion and the bypass duct discharge portion, wherein the discharge duct is configured to receive the bypass flow and the core flow, and to discharge an exhaust flow formed of the bypass flow and the core flow; and means for varying a ratio of the bypass flow to the core flow in the discharge duct. 
     In a refinement, the means for varying is configured to translate between a first position yielding a maximum bypass flow area and a second position yielding a minimum bypass flow area. 
     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.

Technology Classification (CPC): 5