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

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application 61/291,631, filed Dec. 31, 2009, and is incorporated herein by reference. 
    
    
     GOVERNMENT RIGHTS 
     The present application was made with United States government support under Contract No. FA-8650-07-C-2803 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, to heat exchange systems for gas turbine engines. 
     BACKGROUND 
     Gas turbine engines and heat exchange 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 
     One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique gas turbine engine heat exchange system. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and heat exchange systems for gas turbine engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall 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 a gas turbine engine in accordance with an embodiment of the present invention. 
         FIG. 2  depicts an adaptive heat exchange system in accordance with an embodiment of the present invention. 
         FIG. 3  schematically depicts an end view of the heat exchange system of  FIG. 2 . 
         FIGS. 4A and 4B  schematically illustrate an adaptive heat exchange system in accordance with an embodiment of the present invention. 
         FIGS. 5A and 5B  schematically illustrate an adaptive heat exchange system in accordance with an embodiment of the present invention. 
         FIGS. 6A and 6B  schematically illustrate an adaptive heat exchange system 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 now 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 schematically depicted. Gas turbine engine  10  is an aircraft propulsion power plant in the form of a turbofan engine. Gas turbine engine  10  includes a fan  12 , a fan  14 , a compressor system  16 , a diffuser  18 , a combustor  20 , a turbine system with a high pressure (HP) turbine  22  and a low pressure (LP) turbine  24 , an exhaust nozzle system  26 , a bypass duct  28 , a bypass duct  30 , and an adaptive heat exchange system  32 . 
     Each of fan  12  and fan  14  include a plurality of fan blades that pressurize air received at the fan inlet. In one form, fan  12  includes a single stage of circumferentially spaced blades and a single stage of circumferentially spaced vanes. In other forms, fan  12  may not include vanes, or may include multiple stages of both blades and vanes. Likewise, in one form, fan  14  includes a single stage of circumferentially spaced blades and a single stage of circumferentially spaced vanes. In other forms, fan  14  may not include vanes, or may include multiple stages of both blades and vanes. In one form, gas turbine engine  10  includes a flow control system  34  to direct some of the pressurized air discharged from fan  12  into fan  14  and some of the pressurized air into bypass duct  30 . In some embodiments, flow control system  34  is configured to vary the amount of flow as between fan  14  and bypass duct  30 . In some embodiments, flow control system  34  may be an active means of directing flow, e.g., controlled by a control system (not shown). In other embodiments, flow control system  34  may be passive, e.g., controlled based on pressures and/or temperatures in one or more regions of engine  10 , or may be fixed. In still other embodiments, gas turbine engine  10  may not include a flow control system such as flow control system  34 . 
     Compressor system  16  includes a plurality of blades and vanes for compressing air. In one form, compressor system  16  is a single compressor having a plurality of stages of blades and vanes driven by a common shaft at a common speed. In other embodiments, compressor system  16  may include a plurality of compressors operating at the same or different speeds, each of which includes one or more stages of blades, and each of which may also include a desirable number of vane stages. For example, in some forms, compressor system  16  may include an LP compressor and/or an intermediate pressure (IP) compressor and/or an HP compressor. In one form, gas turbine engine  10  includes a flow control system  36  to direct some of the pressurized air discharged from fan  14  into compressor system  16  and some of the pressurized air into bypass duct  28 . In some embodiments, flow control system  36  is configured to vary the amount of flow as between compressor system  16  and bypass duct  28 . In some embodiments, flow control system  36  may be an active means of directing flow, e.g., controlled by a control system (not shown). In other embodiments, flow control system  36  may be passive, e.g., controlled by pressures and/or temperatures in one or more regions of engine  10 , or may be fixed. In still other embodiments, gas turbine engine  10  may not include a flow control system such as flow control system  36 . 
     Diffuser  18  and combustor  20  are fluidly disposed between compressor system  16  and HP turbine  22 . Compressor system  16 , diffuser  18 , combustor  20 , HP turbine  22  and LP turbine  24  form an engine core. HP turbine  22  and LP turbine  24  extract power from the airflow exiting combustor  20 . LP turbine  24  is drivingly coupled to fan  12  via an LP shaft  38 . HP turbine  22  is drivingly coupled to compressor system  16  via an HP shaft  40 . Compressor system  16 , HP shaft  40  and HP turbine  22  form, in part, an HP spool. Fan  12 , LP shaft  38  and LP turbine  24  form, in part, an LP spool. In one form, fan  14  is driven by LP turbine  24 , which may be a direct coupling via LP shaft  38  in some embodiments. In other embodiments, fan  14  may be coupled to LP turbine  24  via a system that allows fan  14  to operate at a different speed than LP turbine  24 , e.g., a fixed speed ratio or a variable ratio gear train. In still other embodiments, fan  14  may be powered by HP turbine  22 . 
     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 fan  14  by flow control system  34 , and the balance is directed into bypass duct  30 . Bypass duct  30  channels the pressurized air to exhaust nozzle system  26 , which provides a component of the thrust output by gas turbine engine  10 . The air directed into fan  14  is further pressurized by fan  14 . Some of the air pressurized by fan  14  is directed into compressor system  16  by flow control system  36 , and the balance is directed into bypass duct  28 . Bypass duct  28  channels the pressurized air to exhaust nozzle system  26 , which provides a component of the thrust output by gas turbine engine  10 . Exhaust nozzle system  26  is operative to control the pressure of the air streams in exhaust nozzle system  26 , including balancing pressures as between bypass duct  28  and bypass duct  30 . In one form, bypass duct  28  is an annular duct that surrounds the core of engine  10 , and bypass duct  30  is an annular duct that surrounds bypass duct  28 . In other embodiments, bypass ducts  28  and  30  may have other geometric configurations suited to the particular application of engine  10 . 
     Compressor system  16  receives the pressurized air from fan  14 , which is compressed and discharged in to diffuser  18 . Diffuser  18  diffuses the core flow that is discharged from compressor system  16 , reducing its velocity and increasing its static pressure. The diffused airflow is directed into combustor  20 . Fuel is mixed with the air in combustor  20 , which is then combusted in a combustion liner (not shown). The hot gases exiting combustor  20  are directed into HP turbine  22 , which extracts energy from the hot gases in the form of mechanical shaft power to drive compressor system  16  via HP shaft  40 . The hot gases exiting HP turbine  22  are directed into LP turbine  24 , which extracts energy in the form of mechanical shaft power to drive fan  12  and fan  14  via LP shaft  38 . The hot gases exiting LP turbine  24  are directed into nozzle  26 , and provide a component of the thrust output by gas turbine engine  10 . 
     The airflow that passes through compressor system  16  and subsequently into combustor  20  is referred to herein as core flow (first stream flow). The pressurized airflow exiting fan  14  and received into bypass duct  28  is referred to herein as a second stream flow; and the pressurized airflow exiting fan  14  and received into bypass duct  30  is referred to herein as a third stream flow. Each of the core flow, second stream flow and third stream flow are working fluid streams. Working fluid in the context of the present application is the air that is directly employed in producing the primary output of engine  10 . Working fluid includes the air that is compressed in compressor system  16  and expanded in turbines  22  and  24 , the air that is pressurized in fan  12  and fan  14 , but does not include secondary flows, such as cooling air flows, pressure balance air and the like. Bypass duct  28 , bypass duct  30  and the flowpath extending through the engine core from fan  12  to turbine  24  are main flowpaths of the working fluid, as opposed to secondary passages for cooling air, pressure balance air and the like. 
     Adaptive heat exchange system  32  is operative to transfer heat from an object of cooling, and to adapt to different cooling medium source conditions. An object of cooling, as used herein, is a fluid, whether in liquid or gas form, and/or one or more components and/or systems that are sought to be cooled. In one form, the object of cooling is air. In a particular form, the object of cooling is air that has been compressed by compressor system  16 . In other embodiments, the object of cooling may be one or more of hydraulic fluid and/or related systems/components, electrical and/or electronic circuits and/or systems, mechanical components and/or systems, and/or other components and/or systems, such as refrigeration components and/or systems. 
     In one form, heat exchange system  32  is operative to transfer heat from the object of cooling using one or more cooling stream sources. Embodiments of adaptive heat exchange system  32  may employ one or more of core flow, second stream flow and third stream flow as cooling medium sources. In other embodiments, heat exchange system  32  is operative to transfer heat from an object of cooling using air from two airways, such as using air as a cooling fluid medium obtained from two of: the core flow, the second stream flow, the third stream flow and an engine ambient environment. 
     In one form, heat exchange system  32  is in fluid communication with compressor system  16 . In such embodiments, heat exchange system  32  is operative to receive pressurized air from compressor system  16 , and extract heat therefrom to reduce the temperature of the received pressurized air. In one form, the airflow that is received by heat exchange system  32  for the removal of heat is a small portion of the core airflow, and is returned to the engine  10  core for use as cooling air in cooling turbine blades and vanes of HP turbine  22 . In another form, the core air that is received by heat exchange system  32  for the removal of heat represents a larger amount of air, e.g., up to all of the core airflow in some embodiments, and is returned to compressor system  16  for additional compression. For example, in such embodiments, heat exchange system  32  may serve as an intercooler system. In still other embodiments, heat exchange system  32  may be employed to reduce the temperature of other objects of cooling. 
     Referring now to  FIG. 2 , some aspects of heat exchange system  32  are schematically depicted. Heat exchange system  32  includes a heat exchanger  42  having a heat exchanger core  44 , a cooling medium inlet  46  for heat exchanger  42 , and a cooling medium outlet  48  for heat exchanger  42 . Some embodiments include one or more additional cooling medium inlets and cooling medium outlets. In one form, heat exchanger  42  is located between bypass duct  28  and bypass duct  30 , although other locations are contemplated herein. In embodiments described herein, heat exchanger  42  is located in bypass duct  28  and/or bypass duct  30 . 
     Heat exchanger  42  structured to remove heat from the object of cooling. In one form, heat exchanger  42  is operative to cool air received from compressor  16 , in which case heat exchange system  32  includes a plurality of passages  50 ,  52 . Passages  50 ,  52  are structured to conduct the object of cooling to and from heat exchanger core  44 . In one form, passages  50 ,  52  include pipes that deliver core airflow to and from heat exchanger core  44 . In other embodiments, other types of passages may be employed in addition to and/or in place of pipes. In other forms, heat exchange system  32  may not include passages  50 ,  52 , e.g., where the object of cooling is an electronic component. In one form, heat exchanger  42  is a parallel flow heat exchanger. In other embodiments, other heat exchanger types may be employed, e.g., counter flow heat exchangers, cross flow heat exchangers and/or mixed flow heat exchangers. 
     The flow conditions in bypass duct  28  and bypass duct  30  may vary significantly during the operation of engine  10 . For example, a high efficiency mode (specific fuel consumption (SFC) mode) of operation may result in different pressures and flow rates than a high thrust mode of operation. In one example, the pressure and flow rate in duct  30  in SFC mode is larger than the pressure and flow rate in high thrust mode. In high thrust mode, the pressure and flow rate in duct  28  are significantly higher than in duct  30 . The pressure differential as between duct  28  and duct  30  and the flow rates in ducts  28  and  30  thus vary with engine output and mode of operation. In one form, heat exchange system  32  is adapted to obtain the cooling medium from one or both of duct  28  and duct  30 . The adaptive performance of heat exchange system  32  may be passively controlled or actively controlled. Embodiments that are passively controlled vary the cooling medium input source passively, e.g., based on pressures, without a control system input. Embodiments that are actively controlled vary the cooling medium input source actively, based on control inputs. 
     Referring now to  FIGS. 4A and 4B , a non-limiting example of aspects of heat exchange system  32  in accordance with an embodiment of the present invention is schematically depicted. In the embodiment of  FIGS. 4A and 4B , heat exchange system  32  includes a heat exchanger  142  depicted in top, side and end views. In one form, heat exchanger  142  is similar to heat exchanger  42 . Heat exchanger  142  includes a plurality of fins  160 , passages  162  for flowing the object of cooling (which in the present example is air from compressor system  16 ), and passages  164  and  166 . Fins  160  are exposed to third stream air from bypass duct  30  via a cooling medium inlet  168  to provide air as a cooling medium to extract heat from the object of cooling. Passages  164  and  166  are exposed to second stream air from bypass duct  28 , and function as an inlet  170  to heat exchanger  142  that supplies air  172  as a cooling medium to fins  160  and through heat exchanger  142 . In one form, passages  164  extend through fins  160 . In one form, passages  164  direct the cooling medium to impinge upon adjacent fins  160 . In one form, passages  166  direct the cooling medium to impinge upon fins  160 . In some embodiments, only one type of passage geometry, such as that illustrated for passages  164  or passages  166  may be employed, with or without impingement cooling. In other embodiments more cooling passage geometries in addition to and/or in place those illustrated for passages  164  and  166  may be employed. In the depiction of  FIGS. 4A and 4B , air  172  and air  174  are both discharged via the outlet of heat exchanger  142  into duct  30 . In one form, passages  164  and  166  are perpendicular to passages  162 , which provides cross-flow heat exchange. In one form, air  174  flows along the length of fins  160 , which in one form are parallel to passages  162 , and which provides parallel flow heat exchange. In other embodiments, other orientations may be employed. 
     In the depiction of  FIG. 4A , engine  10  is operating in high thrust mode, wherein the pressure in duct  28  is greater than the pressure in duct  30 . Accordingly, the cooling is primarily provided by air  172  from the second stream flow supplied by duct  28  via passages  164  and  166 . In the depiction of  FIG. 4B , engine  10  is operating in SFC mode, wherein the pressure in duct  28  is approximately similar to that the pressure in duct  30 . Accordingly, the cooling is primarily provided by air  174  from the third stream flow in duct  30  that moves past fins  160 . The embodiment of  FIGS. 4A and 4B  is a passively controlled system, since no control inputs or valves are used to direct the flow through inlets  168  and  170 . 
     Referring now to  FIGS. 5A and 5B , a non-limiting example of aspects of heat exchange system  32  in accordance with an embodiment of the present invention is schematically depicted. In the embodiment of  FIGS. 5A and 5B , heat exchange system  32  includes a heat exchanger  242  depicted in top, side and end views. In one form, heat exchanger  242  is similar to heat exchanger  42 . Heat exchanger  242  includes a plurality of fins  260 , passages  262  for flowing the object of cooling (which in the present example is air from compressor system  16 ), and a cooling medium inlet  264  for admitting cooling air past fins  260 . Passages  262  are supplied with the object of cooling via ducting that includes hinges  266 . Heat exchanger  242  is disposed in duct  30  adjacent an opening  268  in a wall  270  separating bypass duct  30  from bypass duct  28 . Hinges  266  allow heat exchanger  242  to pivot under the action of a mechanism (not shown) so that inlet  264  may be selectively exposed to bypass duct  28  or bypass duct  30  or both. 
     In the depiction of  FIG. 5A , engine  10  is operating in high thrust mode, wherein the pressure in duct  28  is greater than the pressure in duct  30 . Accordingly, heat exchanger is pivoted inward, and the cooling is primarily provided by air  272  from the second stream flow, which is supplied by duct  28  via cooling medium inlet  264 . In the depiction of  FIG. 5B , engine  10  is operating in SFC mode, wherein the pressure in duct  28  is approximately similar to that the pressure in duct  30 , but the flow rate is greater in duct  30 . Accordingly, the cooling is primarily provided by air  274  from the third stream flow in duct  30 , which is admitted to fins  160  via cooling medium inlet  264 . The embodiment of  FIGS. 5A and 5B  is an actively controlled system, whereby control inputs, e.g., based on pressure and/or flow data in ducts  28  and  30  or other control parameters, are used to activate the mechanism to pivot heat exchanger  242  about hinges  266 . In other embodiments, a passive system may be employed to pivot heat exchanger  242 , e.g., based on the pressures in ducts  28  and  30 . In the depiction of  FIGS. 5A and 5B , air  272  and air  274  are both discharged via the outlet of heat exchanger  242  into duct  30 . 
     Referring now to  FIGS. 6A and 6B , a non-limiting example of aspects of heat exchange system  32  in accordance with an embodiment of the present invention is schematically depicted. In the embodiment of  FIGS. 6A and 6B , heat exchange system  32  includes a heat exchanger  342  depicted in side and end views. In one form, heat exchanger  342  is similar to heat exchanger  42 . Heat exchanger  342  includes a plurality of fins  360 , passages  362  for flowing the object of cooling (which in the present example is air from compressor system  16 ), and passages  364  and  366 . Fins  360  are exposed to air from a bypass duct  378  via a cooling medium inlet  368  to extract heat from the object of cooling. Passages  364  and  366  are also exposed to air from bypass duct  378 . Duct  378  may be any fan bypass duct of a gas turbine engine. 
     In the embodiment of  FIGS. 6A and 6B , an engine ambient environment  380 , such as an engine nacelle or an airstream surrounding bypass duct  378 , forms a pressure sink to receive cooling air discharged from duct  378 . Passages  364  function as an inlet  370  to heat exchanger  342  that supplies air  372  to flow past fins  360  and into and out of heat exchanger  342 . Fins  360  are located in duct  28  in the embodiment of  FIGS. 6A and 6B . In other embodiments, fins  360  may be partially or completely disposed in environment  380 . A plug  376  is controllably employed via a mechanism (not shown) to selectively block or unblock the exit of passage  366  to prevent or allow flow through passage  366 , hence passages  364  and inlet  370 . In other embodiments, other types of valving mechanisms may be employed to turn on or off the flow of cooling medium through heat exchanger  342 , or to modulate the same. 
     In the depiction of  FIGS. 6A and 6B , heat exchanger  342  is controlled to selectively choose between providing cooling using air  304  in duct  378  alone or in conjunction with air  372  bled from duct  378  that is passed through passages  364  and  366  as cooling air  372  to provide additional cooling capacity. In the depiction of  FIGS. 6A and 6B , air  304  is discharged through an outlet of heat exchanger  342  into duct  378 , and air  372  is discharged via an outlet of heat exchanger  342  into environment  380 . 
     Embodiments of the present invention include a gas turbine engine, comprising: an engine core; a fan bypass duct operative to direct a bypass stream around the engine core; an other fan bypass duct operative to direct an other bypass stream around the engine core; and an adaptive heat exchange system operative to cool an object of cooling using air from the fan bypass duct and the other fan bypass duct as a cooling medium. 
     In a refinement, the heat exchange system includes a heat exchanger having a cooling medium inlet and a cooling medium outlet; the cooling medium inlet is selectively exposed to a selected one or both of the fan bypass duct and the other fan bypass duct to receive a cooling medium; and the cooling medium outlet is positioned to discharge the cooling medium into the other bypass duct. 
     In another refinement, the heat exchanger is hinged to selectively expose the cooling medium inlet to the selected one or both of the fan bypass duct and the other fan bypass duct. 
     In yet another refinement, the adaptive heat exchange system includes a heat exchanger operative to exchange heat in a parallel flow mode and a cross flow mode. 
     In still another refinement, the heat exchanger includes a fin operative to transfer heat from the object of cooling; the parallel flow mode directs the cooling medium in a first direction parallel to the fin; and the cross flow mode directs the cooling medium in a second direction not parallel to the fin. 
     In yet still another refinement, the heat exchanger includes a first cooling medium inlet for receiving the cooling medium in the parallel flow mode; and the heat exchanger includes a second cooling medium inlet for receiving the cooling medium in the cross flow mode. 
     In a further refinement, the second cooling medium inlet includes an opening operative to impinge the cooling medium onto the fin. 
     In yet a further refinement, the adaptive heat exchange system is operative to cool the object of cooling using air by selecting the air from one or both of the fan bypass duct and the other fan bypass duct in response to an engine operating condition. 
     In a still further refinement, the adaptive heat exchange system is passively controlled. 
     In a yet still further refinement, the adaptive heat exchange system is actively controlled. 
     Embodiments of the present invention include a gas turbine engine, comprising: a first airway; a second airway; and an adaptive heat exchange system operative to cool an object of cooling using air from the first airway and the second airway as a cooling medium. 
     In a refinement, the first airway is a first working fluid main flowpath; and the second airway is a second working fluid main flowpath. 
     In another refinement, the adaptive heat exchange system includes a heat exchanger having a first cooling medium inlet and a second cooling medium inlet; the first cooling medium inlet is adapted to receive the cooling medium from one of the first airway and the second airway; and the second cooling medium inlet is adapted to receive the cooling medium from the other of the first airway and the second airway. 
     In yet another refinement, the heat exchanger employs impingement cooling. 
     In still another refinement, the adaptive heat exchange system includes a valve operative to control flow through one of the first cooling medium inlet and the second cooling medium inlet. 
     In yet still another refinement, the adaptive heat exchange system includes a cooling medium exit; and wherein the valve is positioned in the cooling medium exit. 
     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 an adaptive heat exchange system having means for cooling air from the compressor prior to being discharged into the turbine. 
     In a refinement, the air is discharged into the turbine as cooling air. 
     In another refinement, the means for cooling air includes means for receiving a cooling medium from more than one cooling medium source. 
     In still another refinement, the means for receiving is actively controlled to select a cooling medium source. 
     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.