Abstract:
A gas turbine system having a plasma actuator flow control arrangement including a compressor section for compressing an airstream, wherein the compressor section includes at least one inlet guide vane for controlling the airstream proximate an inlet portion of the compressor section. Also included is a turbine inlet assembly for ingesting the airstream to be routed to the compressor section. Further included is a plasma actuator disposed within at least one of the inlet portion of the compressor section and the turbine inlet assembly for controllably producing an electric field to manipulate a portion of the airstream.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to gas turbine systems, and more particularly to plasma actuators disposed within such systems. 
         [0002]    Inlet assemblies for gas turbine systems typically include an intake portion that provides an intake path for an airstream to enter the inlet assembly and the intake portions often include conditioning features such as weather hoods or louvers. Downstream of the louvers or hoods, various filtration and airstream conditioning components may be included to treat the airstream. An inlet duct is configured to contain and route the treated airstream to a gas turbine inlet plenum, and subsequently to an inlet portion of a compressor. Routing of the airstream through the inlet assembly typically includes changes in geometry and/or rapid redirection of the airstream, thereby causing flow separation at various regions and results in an undesirable pressure drop of the airstream. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    According to one aspect of the invention, a gas turbine system having a plasma actuator flow control arrangement including a compressor section for compressing an airstream, wherein the compressor section includes at least one inlet guide vane for controlling the airstream proximate an inlet portion of the compressor section. Also included is a turbine inlet assembly for ingesting the airstream to be routed to the compressor section. Further included is a plasma actuator disposed within at least one of the inlet portion of the compressor section and the turbine inlet assembly for controllably producing an electric field to manipulate a portion of the airstream. 
         [0004]    According to another aspect of the invention, a gas turbine system having a plasma actuator flow control arrangement including a turbine inlet assembly for ingesting an airstream to be routed to a compressor section, wherein the turbine inlet assembly includes an outer wall enclosing an airstream path. Also included is a plasma actuator disposed proximate the outer wall of the turbine inlet assembly for controllably producing an electric field to manipulate a portion of the airstream. 
         [0005]    According to yet another aspect of the invention, a gas turbine system having a plasma actuator flow control arrangement including a compressor section for compressing an airstream, wherein the compressor section includes an inlet portion. Also included is a plasma actuator disposed proximate the inlet portion of the compressor section, wherein the plasma actuator controllably produces an electric field to manipulate a portion of the airstream. 
         [0006]    These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0008]      FIG. 1  is a schematic illustration of a gas turbine system; 
           [0009]      FIG. 2  is a side, elevational view of an inlet assembly of the gas turbine system; 
           [0010]      FIG. 3  is a schematic illustration of a plasma actuator disposed within a portion of the gas turbine system; and 
           [0011]      FIG. 4  is a side, cross-sectional view of an inlet portion of a compressor section of the gas turbine system. 
       
    
    
       [0012]    The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    Referring to  FIG. 1 , a gas turbine system is schematically illustrated with reference numeral  10 . The gas turbine system  10  includes a compressor  12 , a combustor  14 , a turbine  16 , a shaft  18  and a fuel nozzle  20 . The compressor  12  and the turbine  16  are coupled by the shaft  18 . The shaft  18  may be a single shaft or a plurality of shaft segments coupled together to form the shaft  18 . Additionally, a turbine inlet assembly  22  ingests an airstream  24  that is filtered and routed to the compressor  12 . 
         [0014]    The combustor  14  uses a combustible liquid and/or gas fuel, such as natural gas or a hydrogen rich synthetic gas, to run the gas turbine system  10 . For example, fuel nozzles  20  are in fluid communication with an air supply and a fuel supply  26 . The fuel nozzles  20  create an air-fuel mixture, and discharge the air-fuel mixture into the combustor  14 , thereby causing a combustion that creates a hot pressurized exhaust gas. The combustor  14  directs the hot pressurized gas through a transition piece into a turbine nozzle (or “stage one nozzle”), and other stages of buckets and nozzles causing rotation of the turbine  16 . Rotation of the turbine  16  causes the shaft  18  to rotate, thereby compressing the air as it flows into the compressor  12 . 
         [0015]    Referring to  FIG. 2 , the turbine inlet assembly  22  is illustrated in greater detail. The turbine inlet assembly  22  includes an entry portion  30  for the airstream  24 , where the entry portion  30  typically comprises one or more weather hoods or louvers. The entry portion  30  provides a path for the airstream  24  to enter an inlet filter compartment  32  from ambient surroundings. In cooler operating environments, various anti-icing devices may be disposed proximate and/or downstream of the entry portion  30  to prevent ice formation and plugging within the turbine inlet assembly  22 . Additionally, optional cooling components may be employed to reduce the dry bulb temperature of the airstream  24 . An inlet duct  34  is configured to contain and route the airstream to an inlet plenum  36 . The inlet duct  34  comprises numerous sections that may vary in orientation and geometric configuration. For example, a first duct portion  38  is shown as having a relatively horizontal orientation prior to redirection through an elbow  40  to a second duct portion  42  having a relatively vertical orientation. The inlet plenum  36  is configured to provide a relatively turbulent-free region for immediate entry of the airstream  24  to the compressor  12 . The airstream  24  is subjected to yet another redirection during entry to the compressor  12  through the inlet plenum  36 . The inlet plenum  36  directs the airstream  24  into a compressor inlet bellmouth  46 . 
         [0016]    Referring to  FIG. 3 , in regions of redirection and/or variance in geometric configuration of the airstream  24  path, flow separation may occur, with a boundary layer forming proximate structural components of the turbine inlet assembly  22 . To reduce flow separation and associated pressure drop within the turbine inlet assembly  22 , a plasma actuator  44  is disposed within the turbine inlet assembly  22 . Although a single plasma actuator is described, it is to be appreciated that a plurality of such plasma actuators may be employed and is dictated by the application of use. The plasma actuator  44  may be disposed at any region of the turbine inlet assembly  22  that subjects the airstream  24  to a rapid change in orientation and/or geometric configuration. Regions proximate the elbow  40 , the inlet plenum  36  and the compressor inlet bellmouth  46  are examples of locations where disposal of the plasma actuator  44  may assist in reduction of flow separation exhibited at such regions. Although the previously mentioned regions are exemplary locations known to benefit from use of the plasma actuator  44 , it is to be understood that the plasma actuator  44  may be located anywhere within the turbine inlet assembly  22 . 
         [0017]    The plasma actuator  44  controllably produces an electric field to manipulate a portion of the airstream  24  proximate an area typically associated with flow separation, including but not limited to an outer wall  48  ( FIG. 2 ) of the turbine inlet assembly  22 , the outer wall  48  defining and enclosing the path of the airstream  24 , or on a wall  50  of the inlet plenum  36 , for example. The plasma actuator  44  includes a first electrode  52 , a second electrode  54  and a dielectric material  56  having a first side  58  and a second side  60 , to which the first electrode  52  and the second electrode  54  are arranged in proximity to, respectively. The dielectric material  56  may be configured for conforming to a variety of geometric surfaces, including non-planar surfaces, as well as relatively planar surfaces. The first electrode  52  and the second electrode  54  are operably connected to an energy source  62 . Both the first electrode  52  and the second electrode  54  comprise relatively low-diameter wires flush-mounted on the wall  50 , for example, but as noted above the first electrode  52  and the second electrode  54  may be positioned at numerous locations within the turbine inlet assembly  22 . The energy source  62  provides alternating current (AC) or direct current (DC) power to the first electrode  52  and the second electrode  54 . Upon reaching a threshold value voltage, the airstream  24  ionizes in a region of the largest electric potential to form plasma. The plasma forms around one of the first electrode  52  and the second electrode  54  and spreads over an area tangential to the wall  50 , in the form of an electric field. The plasma produces a force on the airstream  24 , which in turn causes a change in the pressure distribution along whatever surface the plasma actuator  44  is disposed in proximity to. The change in pressure distribution generally reduces or substantially prevents flow separation when the plasma actuator  44  is energized by the energy source  62 . 
         [0018]    Referring now to  FIG. 4 , an inlet portion  70  of the compressor  12  is illustrated. The inlet portion  70  includes at least one strut  72  that provides structural support proximate an inlet casing  74  of the compressor  12 . Additionally, the inlet portion  70  includes at least one, but typically a plurality of, inlet guide vanes  76  that may have variable aerodynamic vane positions. The angle of the at least one inlet guide vanes  76  may vary based on different ranges of compressor flows (i.e., startup and various unit power output settings), thereby improving operating efficiency of the compressor  12 . For example, during extended turn down operation of the gas turbine system  10 , the angle of the inlet guide vanes  76  may be reduced. An increased chance of flow separation of a portion of the airstream  24  is present during such a configuration of the inlet guide vanes  76 , thereby creating flow disturbances in the inlet portion  70  of the compressor  12 . To reduce flow separation in regions proximate the strut  72  and/or the inlet guide vanes  76 , or more specifically an exterior surface  78  of the inlet guide vanes  76 , the plasma actuator  44  may be disposed proximate one or both component. The plasma actuator  44  has been described in detail above and further description is not necessary. As shown, the plasma actuator  44 , or a plurality of plasma actuators, may be disposed at various locations on the strut  72  and/or the inlet guide vanes  76 . 
         [0019]    Accordingly, the flow profile of the airstream  24  in regions of the turbine inlet assembly  22  and the inlet portion  70  of the compressor  12  may be better controlled, while reducing fluctuations in the airstream  24  that occur due to upstream disturbances. The overall efficiency of the gas turbine system  10  is improved by use of the plasma actuator  44 , which requires a relatively low amount of power consumption with real-time control. 
         [0020]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.