Abstract:
One embodiment of the present invention is a unique compressor. Another embodiment of the present invention is a unique gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for blade tip clearance control for compressors and gas turbine engine compressors. 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. 61/428,803, filed Dec. 30, 2010, entitled COMPRESSOR TIP CLEARANCE CONTROL AND GAS TURBINE ENGINE, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to gas turbine engines and compressors, and more particularly, to compressor blade tip clearance control. 
       BACKGROUND 
       [0003]    Blade tip clearance control for compressors and gas turbine engine compressors 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 compressor. Another embodiment of the present invention is a unique gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for blade tip clearance control for compressors and gas turbine engine compressors. 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  illustrates some aspects of a non-limiting example of a compressor with a tip clearance control system in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0008]    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. 
         [0009]    Referring to  FIG. 1 , there are illustrated some aspects of a non-limiting example of gas turbine engine  20  in accordance with an embodiment of the present invention. In one form, engine  20  is a two spool engine having a high pressure spool  24  and a low pressure spool  26 . In other embodiments, engine  20  may include three or more spools, or may include only a single spool. In one form, engine  20  is a turbofan engine, wherein low pressure spool  26  powers a propulsor  28  in the form of a turbofan (fan), referred to herein as a turbofan or a fan. In other embodiments, engine  20  may be a turboprop engine, wherein low pressure spool  26  powers a propulsor  28  in the form of a propeller system (not shown), e.g., via a reduction gearbox (not shown). In still other embodiments, engine  20  may be a marine and/or industrial gas turbine engine, e.g., for providing marine and/or land propulsion, power generation, fluid pumping and/or other work. 
         [0010]    In one form, engine  20  includes, in addition to fan  28 , a bypass duct  30 , a compressor  32 , a diffuser  34 , a combustor  36 , a high pressure (HP) turbine  38 , a low pressure (LP) turbine  40 , a nozzle  42 A, and a nozzle  42 B. In other embodiments, there may be, for example, an intermediate pressure spool having an intermediate pressure turbine. 
         [0011]    Bypass duct  30  is in fluid communication with nozzle  42 B. Diffuser  34  is in fluid communication with compressor  32 . Combustor  36  is fluidly disposed between compressor  32  and turbine  38 . In one form, combustor  36  includes a combustion liner (not shown) that contains a continuous combustion process. In other embodiments, combustor  36  may take other forms, and may be, for example, a wave rotor combustion system, a rotary valve combustion system, and/or a slinger combustion system, and may employ deflagration and/or detonation combustion processes. Turbine  40  is fluidly disposed between turbine  38  and nozzle  42 B. In the depicted embodiment, engine  20  core flow is discharged through nozzle  42 A, and the bypass flow is discharged through nozzle  42 B. In other embodiments, other nozzle arrangements may be employed, e.g., a common nozzle for core and bypass flow; a nozzle for core flow, but no nozzle for bypass flow; or another nozzle arrangement. Bypass duct  30  and compressor  32  are in fluid communication with fan  28 . 
         [0012]    Fan  28  includes a fan rotor system  48 . In various embodiments, fan rotor system  48  includes one or more rotors (not shown) that are powered by turbine  40 . Fan  28  may include one or more vanes (not shown). Bypass duct  30  is operative to transmit a bypass flow generated by fan  28  around the core of engine  20 . Compressor  32  includes a compressor rotor system  50 . In various embodiments, compressor rotor system  50  includes one or more rotors (not shown) that are powered by turbine  38 . Turbine  38  includes a turbine rotor system  52 . In various embodiments, turbine rotor system  52  includes one or more rotors (not shown) operative to drive compressor rotor system  50 . Turbine rotor system  52  is drivingly coupled to compressor rotor system  50  via a shafting system  54 . Turbine  40  includes a turbine rotor system  56 . In various embodiments, turbine rotor system  56  includes one or more rotors (not shown) operative to drive fan rotor system  48 . Turbine rotor system  56  is drivingly coupled to fan rotor system  48  via a shafting system  58 . In various embodiments, shafting systems  54  and  58  include 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 in one or both of shafting systems  54  and  58 . In one form, rotor systems  48 ,  50 ,  52  and  56 , and shafting systems  54  and  58  rotate about an engine centerline  46 . Turbine  40  is operative to discharge an engine  20  core flow to nozzle  42 A. 
         [0013]    During normal operation of gas turbine engine  20 , air is drawn into the inlet of fan  28  and pressurized by fan rotor system  48 . Some of the air pressurized by fan rotor system  48  is directed into compressor  32  as core flow, and some of the pressurized air is directed into bypass duct  30  as bypass flow. Compressor  32  further pressurizes the portion of the air received therein from fan  28 , which is then discharged into diffuser  34 . Diffuser  34  reduces the velocity of the pressurized air, and directs the diffused core airflow into combustor  36 . Fuel is mixed with the pressurized air in combustor  36 , which is then combusted. The hot gases exiting combustor  36  are directed into turbines  38  and  40 , which extract energy in the form of mechanical shaft power to drive compressor  32  and fan  28  via respective shafting systems  54  and  58 . In addition, in some embodiments, such as in turbofan, propjet or jet configurations, turbine  40  generates a thrust output. 
         [0014]    Referring to  FIG. 2 , some aspects of a non-limiting example of compressor  32  with a tip clearance control system  60  in accordance with an embodiment of the present invention is schematically depicted. Included as part of compressor rotor system  50  are a plurality of rotating compressor blades  62 ,  64 ,  66 ,  68 ,  70  and  72 , each of which is disposed in a corresponding compressor blade stage having blades spaced apart circumferentially. In one form, compressor  32  is an axial compressor. In other embodiments, compressor  32  may be a centrifugal compressor or an axi-centrifugal compressor. In one form, compressor  32  includes a plurality of vanes  74 ,  76 ,  78 ,  80  and  82  disposed axially adjacent to compressor blades  64 ,  66 ,  68 ,  70  and  72 . In some embodiments, compressor  32  may not include vanes. A vane  84  is disposed downstream of blade  62 . In one form, vane  84  is considered a part of diffuser  34 . In other embodiments, vane  84  may be considered a part of compressor  32 . 
         [0015]    Vanes  74 ,  76 ,  78 ,  80  and  82  are mechanically supported by an inner compressor case  86 . Inner compressor case  86  is mechanically supported by an outer compressor case  88 . Outer compressor case  88  is disposed around inner compressor case  86 . Vane  84  is supported by diffuser  34 . In one form, inner compressor case  86  is formed of a plurality of ring cases, e.g., including ring cases  90 ,  92  and  94 . In other embodiments, inner compressor case  86  may be a single integrally formed structure, or may be any number of structures assembled and/or joined together. Blades  62 ,  64  and  66  have respective tips  96 ,  98  and  100  disposed opposite inner compressor case  86 . In one form, ring cases  90 ,  92  and  94  include respective abradable blade tracks  102 ,  104  and  106  disposed opposite tips  96 ,  98  and  100 . Other embodiments may not include abradable blade tracks, e.g., structural or non-structural materials of inner compressor case  86  may be disposed opposite blade tips  96 ,  98  and/or  100  without an intervening abradable material. In various embodiments, one or more coatings and/or treatments may or may not be applied to inner compressor case  86  or portions thereof opposite blade tips  96 ,  98  and/or  100 . 
         [0016]    Tip clearance control system  60  is configured to control a clearance between the blade tips  96 ,  98  and  100  and inner compressor case  86 , e.g., blade tracks  102 ,  104  and  106 . In one form, in order to control tip clearance between blade tips  96 ,  98  and  100  and inner compressor case  86 , e.g., blade tracks  102 ,  104  and  106 , tip clearance control system  60  impinges a fluid onto inner compressor case  86 . In one form, the fluid is air. In other embodiments, other fluids may be employed in addition to or in place of air. In one form, the air is air that has been compressed by compressor  32 . In other embodiments, other sources of air may be employed. In one form, the impingement fluid is cooled prior to impingement upon inner compressor case  86 . In other embodiments, the fluid may not be cooled and/or may be heated or may be supplied without any heating or cooling, e.g., depending on the temperature of the fluid and other aspects of a particular application. 
         [0017]    Blades  62 ,  64 ,  66 ,  68 ,  70  and  72  and vanes  74 ,  76 ,  78 ,  80  and  82  are disposed in a compressor flowpath  108  formed in part by inner compressor case  86 , and by structures (not shown) disposed at root portions of blades  62 ,  64 ,  66 ,  68 ,  70  and  72  and vanes  74 ,  76 ,  78 ,  80  and  82 . Vane  84  is disposed in a diffuser flowpath  110  located immediately downstream of compressor flowpath  108 . 
         [0018]    Extending from ring case  90  is a support structure  112 . Support structure  112  extends between inner compressor case  86  and outer compressor case  88 , and supports the aft end of inner compressor case  86 . Support structure  112  is configured for radial flexibility for absorbing a thermal growth differential between inner compressor case  86  and outer compressor case  88 , e.g., resulting from tip clearance control system  60  impinging the fluid onto inner compressor case  86 . In one form, the radial flexibility is supplied by extending support structure  112  in axial directions in addition to radial directions. In other embodiments, other configurations or arrangements may be employed to provide radial flexibility. In one form, support structure  112  is attached to outer compressor case  88  via a bolted flange arrangement. In other embodiments, support structure  112  may be coupled or affixed to outer compressor case  88  via one or more other arrangements, including being integral with outer compressor case  88 . 
         [0019]    Extending from ring case  94  is a support structure  114 . Support structure  114  extends between inner compressor case  86  and outer compressor case  88 , and supports the forward end of inner compressor case  86 . Support structure  114  is configured for radial flexibility for absorbing a thermal growth differential between inner compressor case  86  and outer compressor case  88 , e.g., resulting from tip clearance control system  60  impinging the fluid onto inner compressor case  86 . In one form, the radial flexibility is supplied by extending support structure  114  in an axial direction in addition to radial directions. In other embodiments, other configurations or arrangements may be employed to provide radial flexibility. In one form, support structure  114  is attached to outer compressor case  88  via a bolted flange arrangement. In other embodiments, support structure  114  may be coupled or affixed to outer compressor case  88  via one or more other arrangements, including being integral with outer compressor case  88 . 
         [0020]    In one form, the fluid that is impinged upon inner compressor case  86  by tip clearance control system  60  is compressor  32  discharge air  116  that has been diffused by diffuser  34 . In one form, the air is supplied through an opening  118  in a diffuser vane  120 . Air  116  then passes through a cavity  122  defined between support structure  112  and a diffuser support structure  124 . Air  116  then passes from cavity  122  into a discharge tube  126  extending from a discharge opening  128  in outer compressor case  88 . In other embodiments, other arrangements for obtaining air  116  may be employed. 
         [0021]    In one form, a joint  130  is formed at the interface between diffuser  34  and inner compressor case  86 . Joint  130  is configured to permit relative radial motion between inner compressor case  86  and diffuser  34 , e.g., resulting from the impingement of air  116  onto inner compressor case  86 . In other embodiments, joint  130  may be formed between inner compressor case  86  and one or more other static structures. In one form, a bellows seal  132  forms a part of joint  130 , which permits the relative radial motion while sealing the interface between inner compressor case  86  and diffuser  34 . In other embodiments, other sealing arrangements may be employed. 
         [0022]    In one form, air  116  is cooled by a cooler  134  prior to being impinged upon inner compressor case  86 . In other embodiments, air  116  may be conditioned to any desired temperature via one or more thermal management means. In one form, cooler  134  is a heat exchanger, e.g., an air-to-air heat exchanger or an air/fuel heat exchanger. In other embodiments, other cooling schemes may be employed. In one form, cooler  134  is mounted on engine  20  and considered a part thereof. In other embodiments, cooler  134  may be mounted elsewhere. 
         [0023]    Air  116  exiting cooler  134  is supplied to a valve  136 . Valve  136  is configured to control the flow of air  116 , and is disposed upstream of impingement openings that impinge air  116  onto inner compressor case  86 . In one form, valve  136  is configured to modulate the flow of air  116  between a maximum flow amount and a minimum flow amount. In one form, the minimum flow amount is zero flow of air  116 . In other embodiments, valve  136  may be an on/off valve. 
         [0024]    Air  116  exiting valve  136  is passed via a supply tube  142  extending from a supply opening  144  in outer compressor case  88  into a distribution channel  146  formed between support structures  112  and  114 , outer compressor case  88  and inner compressor case  86 . In various embodiments, more than one of each of cooler  134  and valve  136  may be employed. For example, in some embodiments, a plurality of coolers  134  and valves  136  may be employed, e.g., with corresponding discharge tubes  126  and discharge openings  128 , and supply tubes  142  and supply openings  144 , respectively, spaced apart circumferentially around outer compressor case  88 . In some embodiments, such an arrangement may be employed to preferentially cool different circumferential sectors of inner compressor case  86 , e.g., to control the roundness of inner compressor case  86  during the operation of engine  20 . 
         [0025]    Distribution channel  146  is configured to distribute air  116  from supply opening  144  to desired locations for subsequent impingement upon inner compressor case  86 . Disposed adjacent to inner compressor case  86  is a fluid impingement structure  150  having a plurality of impingement openings  152  configured to impinge air  116  onto inner compressor case  86 . Tip clearance control system  60  supplies air  116  to impingement structure  150  and impingement openings  152  via supply opening  144  and distribution channel  146 . In one form, impingement openings  152  are angled radially inward toward the center of rotation of the compressor blades, i.e., engine centerline  46  ( FIG. 1 ). In other embodiments, one or more impingement openings  152  may also be angled in one or more circumferential and/or axial directions, e.g., to direct bulk flow of air  116  in one or more desired directions. After having impinged onto inner compressor case  86 , air  116  is directed into compressor flowpath  108  via openings  160  and  162 . 
         [0026]    In one form, fluid impingement structure  150  is an impingement plate, i.e., a plate having impingement openings  152  formed therein. In one form, the impingement plate is disposed adjacent to inner compressor case  86 , and extends circumferentially around inner compressor case  86 . In other embodiments, the impingement plate may only be disposed adjacent to one or more desired parts of inner compressor case  86 . In various embodiments, the impingement plate may be one or more flat plates and/or one or more curved plates. In other embodiments impingement structure may take other forms, e.g., an impingement tube. 
         [0027]    Embodiments of the present invention include a compressor, comprising: a rotating compressor blade having a blade tip; a compressor case having a blade track disposed opposite the blade tip; and a tip clearance control system including a fluid impingement structure having a plurality of impingement openings configured to impinge a fluid onto the compressor case, wherein the tip clearance control system is configured to control a clearance between the blade tip and the blade track by impinging the fluid onto the compressor case. 
         [0028]    In a refinement, the fluid is air compressed by the compressor. 
         [0029]    In another refinement, the fluid is cooled prior to impingement onto the compressor case. 
         [0030]    In yet another refinement, the compressor case is an inner compressor case, further comprising an outer compressor case disposed around the inner compressor case. 
         [0031]    In still another refinement, the inner compressor case is mechanically supported by the outer compressor case. 
         [0032]    In yet still another refinement, the compressor further comprises a support structure extending between the inner compressor case and the outer compressor case, wherein the support structure is configured for radial flexibility for absorbing a thermal growth differential between the inner compressor case and the outer compressor case resulting from impingement of the fluid onto the inner compressor case. 
         [0033]    In a further refinement, the compressor further comprises an other support structure extending between the inner compressor case and the outer compressor case, wherein the fluid is supplied to the plurality of impingement openings via a supply opening in the outer compressor case; and wherein the support structure and the other support structure form a distribution channel configured to distribute the fluid from the supply opening to a desired location for subsequent impingement upon the inner compressor case. 
         [0034]    In a yet further refinement, the fluid impingement structure is an impingement plate having the plurality of impingement openings therein; and wherein the impingement plate is disposed adjacent to at least part of the compressor case. 
         [0035]    In a still further refinement, at least one of the impingement openings is angled radially inward toward the center of rotation of the rotating compressor blade. 
         [0036]    In a yet still further refinement, the compressor further comprises a compressor flowpath, wherein the compressor is configured to discharge the fluid into the compressor flowpath after impingement of the fluid onto the compressor case. 
         [0037]    Embodiments of the present invention include a gas turbine engine, comprising: a compressor including a rotating compressor blade having a blade tip, and a compressor case disposed opposite the blade tip; a fluid impingement structure having a plurality of impingement openings configured to impinge a fluid onto the compressor case; a combustor in fluid communication with the compressor; and a turbine in fluid communication with the combustor. 
         [0038]    In a refinement, the gas turbine engine further comprises a tip clearance control system configured to control a clearance between the blade tip and the compressor case by impinging the fluid onto the compressor case, wherein the tip clearance control system is configured to supply the fluid to the fluid impingement structure. 
         [0039]    In another refinement, the gas turbine engine further comprises a cooler configured to cool the fluid prior to impingement onto the compressor case. 
         [0040]    In yet another refinement, the cooler is a heat exchanger. 
         [0041]    In still another refinement, the gas turbine engine further comprises a valve configured to control a flow of the fluid, wherein the valve is fluidly disposed upstream of the impingement openings. 
         [0042]    In yet still another refinement, the valve is configured to modulate the flow of the fluid between a maximum flow amount and a minimum flow amount. 
         [0043]    In a further refinement, the minimum flow amount is zero flow of the fluid. 
         [0044]    In a yet further refinement, the gas turbine engine further comprises: a static structure adjacent to the compressor case; and a joint configured to permit relative radial motion as between the compressor case and the static structure. 
         [0045]    Embodiments of the present invention include a gas turbine engine, comprising: a compressor including a rotating compressor blade having a blade tip, and a compressor case disposed opposite the blade tip; a combustor in fluid communication with the compressor; a turbine in fluid communication with the combustor; and means for controlling a clearance between the blade tip and the compressor case by impinging a fluid onto the compressor case. 
         [0046]    In a refinement, the means for controlling includes a fluid impingement structure having a plurality of impingement openings configured to impinge the fluid onto the compressor case. 
         [0047]    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.