Abstract:
One embodiment of the present invention is a unique turbine engine. Another embodiment is a unique turbine engine powered system. Another embodiment is a hybrid bearing system for use in a turbine engine and/or a turbine engine powered system. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for hybrid bearings, turbine engine systems with one or more hybrid bearings and turbine engine powered systems with one or more hybrid bearings. 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 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application 61/290,302, filed Dec. 28, 2009, and is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to turbine engines and systems powered by turbine engines, and more particularly, to turbine engine powered systems with hybrid bearings. 
       BACKGROUND 
       [0003]    Bearing systems that supports rotor systems, such as rotor systems of turbine engines and machinery driven thereby, 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 turbine engine. Another embodiment is a unique turbine engine powered system. Another embodiment is a hybrid bearing system for use in a turbine engine and/or a turbine engine powered system. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for hybrid bearings, turbine engine systems with one or more hybrid bearings and turbine engine powered systems with one or more hybrid bearings. 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 
         [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 depicts a turbine powered system in accordance with an embodiment of the present invention. 
           [0007]      FIG. 2  is a cross section along an axial plane of a hybrid bearing system in accordance with an embodiment of the present invention. 
           [0008]      FIG. 3  is a cross section along a longitudinal plane of the hybrid bearing system of claim  2 . 
       
    
    
     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 now to the drawings, and in particular  FIG. 1 , there is shown a non-limiting example of an embodiment of the present invention in the form of a system  10 . System  10  includes a work machine  12  powered by a turbine engine  14 . In one form, system  10  is a generator set, for example, in which case work machine  12  is a generator. In other embodiments, other types of work machines may be employed, such as pumps or compressors. In one form, turbine engine  14  is a gas turbine engine. In other embodiments, turbine engine  14  may be a steam turbine engine. The gas turbine engine of  FIG. 1  is a single spool machine. In other embodiments, the gas turbine engine may be a multi-spool machine having more than one rotor system. In one form, work machine  12  is drivingly coupled to turbine engine  14  via a gearbox, such as a reducing gearbox  16 . In other embodiments, work machine  12  may be coupled to turbine engine  14  directly or via a speed-increasing gearbox. 
         [0011]    System  10  includes a rotor system having a substantially horizontal axis of rotation, and which is supported by bearings. In one form, the rotor system includes rotors in work machine  12 , turbine engine  14  and gearbox  16 . In other embodiments, the rotor system may pertain to only one or more of work machine  12 , turbine engine  14  and gearbox  16 . Each rotor is supported by one or more bearings. For example, work machine  12  includes a work machine rotor  18  supported by bearings  20  and  22 . Work machine rotor  18  extends to gearbox  16 , and is supported at gearbox  16  by a bearing  24 . Although depicted as a unified single piece rotor, it will be understood that work machine rotor  18  may be an assembly of more than one component. 
         [0012]    Turbine engine  14  includes a compressor  26 , a combustor  28  and a turbine  30 . Compressor  26  and turbine  30  are drivingly coupled via a shaft  32 . Compressor  26 , turbine  30  and shaft  32  are part of an engine rotor  34 . Engine rotor  34  is supported by a bearing  36  and a bearing  38 . An output shaft  40  couples turbine engine  14  to gearbox  16 . Output shaft  40  is supported by bearing  36  at turbine engine  14  and by a bearing  42  at gearbox  16 . It will be understood that the present invention is not limited to the rotor system or bearing arrangement thus illustrated and described. Rather, other rotor system and bearing arrangements may be employed, for example, having a greater or lesser number of bearings. Although depicted as a unified single piece rotor, it will be understood that engine rotor  34  may be an assembly of more than one component. 
         [0013]    During normal operation, air is drawn into compressor  26 , which compresses the air and delivers it to combustor  28 . Fuel is added to the pressurized air discharged from compressor  26  and is combusted in combustor  28 . The resulting hot gas stream is passed to turbine  30 , which extracts mechanical power from the hot gas stream. Some of the mechanical power is delivered via shaft  32  to compressor  26  for driving compressor  26 . Some of the mechanical power is delivered via shaft  32  to output shaft  40  for driving work machine  12 . Bearings  20 ,  22 ,  24 ,  36 ,  38  and  42  support work machine rotor  18  and engine rotor  34  during normal operation and during startup of system  10 . 
         [0014]    Typically, bearings employ oil as a lubricant, which requires associated plumbing, sumps, an oil and scavenge pump system, and a cooling system. In order to reduce or eliminate necessity of a lubrication system, and in order to reduce start up loads and wear of bearing components, one or more of bearings  20 ,  22 ,  24 ,  36 ,  38  and  42  may be a hybrid bearing. In the depicted embodiment of  FIG. 1 , bearing  38  is a hybrid bearing system. 
         [0015]    Referring now to  FIGS. 2 and 3 , a cross section of hybrid bearing  38  is depicted. In one form, hybrid bearing  38  includes a fluid bearing. In one form, the fluid bearing is a gas bearing in the form of a compliant foil bearing, such as a hydrodynamic air foil bearing  44 . In other embodiments, other fluid bearing types may be employed. During normal operation of system  10 , foil bearing  44  supports the rotor system, in particular, the aft end of engine rotor  34 , applying an upward force to the rotor system via an air film generated at the interface between the rotor&#39;s journal and the hydrodynamic foil of the bearing. The air film may be dependent upon the journal being in a state of rotation. In one form, the air film is a hydrodynamic film. In one form, the hybrid bearing also includes a magnetic bearing  46 . During startup, when no air film is present in the gas bearing, magnetic bearing  46  applies an upward force to the rotor system to support the rotor, thereby reducing starting loads and wear on the gas bearing&#39;s foil. During operation of system  10 , an interruption of power to magnetic bearing  46  may have little or no adverse effect, since engine rotor  34  would be supported by compliant foil bearing  44 . 
         [0016]    Foil bearing  44  includes a housing  48 , a bump foil  50  and a hydrodynamic foil, referred to herein as a top foil  52 . Housing  48  supports bump foil  50 , which supports top foil  52 . Bump foil  50  provides compliance to foil bearing  44 , e.g., in the event engine rotor  34  impacts foil bearing  44 . Top foil  52  supports the hydrodynamic air film that supports engine rotor  34 . 
         [0017]    Magnetic bearing  46  includes an active magnetic actuator  54 . Active magnetic actuator  54  includes an electromagnet  56 , a gap sensor  58  and a controller  60 . Controller  60  is communicatively coupled to gap sensor  58  via a communications link  62 . In one form, gap sensor  58  is a Hall-effect transducer. In other embodiments, other sensor types may be employed. For example, an optical sensor may be employed in other embodiments. 
         [0018]    Controller  60  is communicatively coupled to electromagnet  56  via a communications link  64 . In one form, communications links  62  and  64  are wired connections. In other embodiments, other types of communications links may be employed for either or both of communications links  62  and  64 , e.g., wireless and/or optical links. Although depicted adjacent to electromagnet  56 , it will be understood that gap sensor  58  and controller  60  may be positioned remotely therefrom. 
         [0019]    Gap sensor  58  is structured to sense the radial position of engine rotor  34 , e.g., relative to magnetic bearing  46 , e.g., by sensing the gap between engine rotor  34  and electromagnet  56 . Controller  60  is configured to execute program instructions to operate electromagnet  56 , including turning electromagnet  56  on and off to selectively attract a magnetic portion of engine rotor  34  to lift engine rotor  34  off foil bearing  44  during startup of turbine engine  14 . Controller  60  is also configured to execute program instructions to provide active damping of the rotor system using electromagnet  56 , e.g., active damping of engine rotor  34 . In one form, the active damping is provided in the vertical plane. In other embodiments, active damping may be provided in other planes in addition to or in place of the vertical plane. 
         [0020]    In one form, controller  60  is microprocessor based and the program instructions are in the form of software stored in a memory, e.g., of controller  60  (not shown). However, it is alternatively contemplated that the controller and program instructions may be in the form of any combination of software, firmware and hardware, including state machines, and may reflect the output of discreet devices and/or integrated circuits, which may be co-located at a particular location or distributed across more than one location, including any digital and/or analog devices configured to achieve the same or similar results as a processor-based controller executing software or firmware based instructions. 
         [0021]    Engine rotor  34  includes a portion serving as a bearing journal, journal  66 , which includes a magnetic journal portion  68  and a ring  70 . In various embodiments, magnetic journal portion  68  may be magnetic in the active and/or passive sense. The “active” sense refers to the magnetic journal portion having the property of emanating a magnetic field, such as a magnetite lodestone or an electromagnet. The “passive” sense refers to the material having the property of being responsive to an external magnetic field, e.g., a ferromagnetic material. In one form, magnetic journal portion  68  includes a lamination stack  72  in engagement with engine rotor  34 , e.g., in the form of a stack of ferromagnetic lamination rings piloted by engine rotor  34 . Lamination stack  72  provides a magnetic component to journal  66  having less eddy currents than were a continuous and homogenous solid metal journal employed. Ring  70  is disposed around lamination stack  72  and positioned at the same axial location on engine rotor  34  as foil bearing  44 . Ring  70  provides a smooth surface for compliant foil bearing  44  of hybrid bearing  38 . 
         [0022]    Active magnetic actuator  54 , and in particular, electromagnet  56 , is positioned above and adjacent to magnetic journal portion  68 , and extends partially around journal  66  an arc length  74 . In one form, arc length  74  is approximately 60 degrees, although other arc lengths may be employed in other embodiments. In one form, active magnetic actuator  54  is operable to attract magnetic journal portion  68 , to thereby to thereby apply an upward force to lift magnetic journal portion  68 , and hence engine rotor  34  off foil bearing  44 . In other embodiments, active magnetic actuator  54  may additionally or alternatively be operable to repel magnetic journal portion  68 , in which case, magnetic journal portion  68  would include a suitable magnetic pole. 
         [0023]    Foil bearing  44  is positioned adjacent to magnetic journal portion  68  at the same journal axial location as active magnetic actuator  54 . Foil bearing  44  extends around journal  66  an arc length  76 . In one form, arc length  76  is approximately 300 degrees, although other arc lengths may be employed in other embodiments. Foil bearing  44  is positioned circumferentially adjacent to active magnetic actuator  54 , in particular, electromagnet  56 , and hence arc length  74  and arc length  76  do not overlap. Foil bearing  44  is operable to support a portion of engine rotor  34 , e.g. the aft portion. Top foil  52  is disposed partially around magnetic journal portion  68 , e.g., arc length  76 , in order to support engine rotor  34 . 
         [0024]    Both foil bearing  44  and magnetic bearing  46  may be employed to operate system  10 . For example, when starting turbine engine  14 , magnetic bearing  46  is operated to lift the aft end of engine rotor  34  off foil bearing  44 . In doing so, gap sensor  58  senses the proximity of journal  66  of engine rotor  34  to gap sensor  58 . The proximity data is provided as feedback to controller  60  via communications link  62 , which controls the output of electromagnet  56 . Controller  60  supplies control signals to electromagnet  56  via communications link  64  to maintain a desired gap, e.g., the gap between electromagnet  56  and journal  66 . The desired gap may be selected so as to ensure contact between journal  66  and top foil  52  is reduced or eliminated. This may reduce or prevent wear of foil bearing  44  during startup, and may also reduce the starting loads by reducing or preventing contact between journal  66  of engine rotor  34  and top foil  52  of foil bearing  44 . 
         [0025]    As the rotational velocity of engine rotor  34  increases, a hydrodynamic air film is generated between ring  70  of journal  66  and top foil  52 . Once the air film is sufficient to support the weight of the aft end of engine rotor  34 , the lift generated by magnetic bearing  46  may be reduced or eliminated. 
         [0026]    During the operation of turbine engine  14 , engine rotor  34  oscillations may be sensed by gap sensor  58 , e.g. oscillations in the vertical plane. Gap sensor  58  may sense the oscillations based on the proximity of the journal  66  to gap sensor  58 . The sensed data may be provided as feedback to controller  60  via communications link  62 . Controller  60  may supply control signals to electromagnet  56  via communications link  64  to selectively attract magnetic journal portion  68 , i.e., to switch electromagnet  56  on and off and/or otherwise vary the output of electromagnet  56  in response to the output of gap sensor  58 . Active magnetic actuator  54  may thereby provide damping of engine rotor  34 , for example, active damping in the vertical plane. In other embodiments, active magnetic actuator  54  may be controlled to provide a continuous or variable magnetic force during engine operation, without providing damping of engine rotor  34 . In still other embodiments, active magnetic actuator  54  may be employed only during engine start, and may be shut off during normal engine  14  operation. 
         [0027]    Embodiments of the present invention include a hybrid bearing system. They hybrid bearing system may include a journal having a magnetic journal portion; a magnetic actuator positioned adjacent the magnetic journal portion and extending around the journal a first arc length, wherein the magnetic actuator is operable to at least one of attract and repel the magnetic journal portion; and a fluid bearing positioned adjacent the magnetic journal portion and at a same journal axial location as the magnetic actuator, the fluid bearing extending around the journal a second arc length; wherein the first arc length is nonoverlapping of the second arc length. 
         [0028]    In a refinement of the hybrid bearing system, the magnetic actuator is structured to selectively attract the magnetic journal portion. 
         [0029]    In another refinement of the hybrid bearing, the magnetic actuator includes an electromagnet and a controller communicatively coupled to the electromagnet, wherein the controller is configured to execute program instructions to provide active damping of the journal using the electromagnet. 
         [0030]    In yet another refinement of the hybrid bearing system, the journal is oriented horizontally, and the magnetic actuator is structured to lift the journal off the fluid bearing during a startup of rotation of the journal. 
         [0031]    In still another refinement of the hybrid bearing system, the fluid bearing is a hydrodynamic gas bearing. The fluid bearing may include a hydrodynamic foil disposed partially around the journal. The fluid bearing may be a compliant foil bearing. The fluid bearing may also include a housing and a bump foil disposed between the hydrodynamic foil and the housing. 
         [0032]    In yet still another refinement, the magnetic journal portion includes a lamination stack, further comprising a ring disposed around the lamination stack and positioned at the same axial location as the fluid bearing. In a further refinement, the magnetic actuator is an active magnetic actuator. 
         [0033]    Another embodiment of the present invention may include a system, comprising, a rotor system having a magnetic journal portion and a substantially horizontal axis of rotation; and a hybrid bearing coupled to the rotor system for supporting at least a portion of the rotor system, the hybrid bearing including: an active magnetic actuator positioned above the magnetic journal portion and extending partially around the magnetic journal portion, wherein the magnetic actuator is operable to apply an upward force to the magnetic journal portion; and a gas bearing positioned adjacent the magnetic journal portion and circumferentially adjacent the active magnetic actuator, the gas bearing extending partially around the magnetic journal portion, wherein the gas bearing is operable to support the portion of the rotor system. 
         [0034]    In a refinement of the system, the gas bearing is a hydrodynamic bearing. The gas bearing may include a hydrodynamic foil disposed partially around the magnetic journal portion. The gas bearing may be a compliant foil bearing. The gas bearing may include a housing and a bump foil disposed between the hydrodynamic foil and the housing. 
         [0035]    In other refinements, the magnetic journal portion includes a lamination stack, and the system further includes a ring disposed around the lamination stack and positioned at the same axial location as the fluid bearing. 
         [0036]    In another refinement, the active magnetic actuator includes an electromagnet and a controller communicatively coupled to the electromagnet, wherein the controller is configured to execute program instructions to provide active damping of the rotor system using the electromagnet. 
         [0037]    In yet another refinement, the damping is active damping in a vertical plane. 
         [0038]    In still another refinement, the system further includes a gap sensor configured to sense a radial position of the rotor system. 
         [0039]    In a yet still another refinement, the active magnetic actuator includes an electromagnet, wherein the electromagnet and the gas bearing do not overlap circumferentially. 
         [0040]    Yet another embodiment includes a turbine powered system, comprising: a turbine, a rotor system having a substantially horizontal axis of rotation, wherein the rotor system and the turbine are coupled at least one of mechanically and fluidly; and a hybrid bearing coupled to the rotor system for supporting at least a portion of the rotor system. The hybrid bearing includes: means for magnetically applying a first upward force to the rotor system; and means for pneumatically applying a second upward force to the rotor system. 
         [0041]    In a refinement, the turbine powered system further comprises means for actively damping the rotor system. 
         [0042]    In another refinement, the turbine powered system further comprises a work machine powered by the turbine, wherein the rotor system includes a rotor of the work machine supported at least in part by the hybrid bearing. In yet another refinement, the work machine is a generator. 
         [0043]    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.