Abstract:
A turbine power plant employs a radial staging of a liquid injection system to provide a uniform fluid distribution, for use in wet compression. The liquid injection system can be actuated to inject liquid to various radial regions of an air intake case of the turbine power plant. During a stage one actuation, liquid is directed to a first radial region of the air intake case. During a stage two actuation, liquid is directed to the first radial region and also to a second radial region of the air intake case.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 12/329,124, filed on Dec. 5, 2008, entitled “Radial Staging of a Liquid Injection System for Power Plants”, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to the radial staging method and configuration of a liquid injection system for power plants, and more particularly to the radial staging of a liquid injection system configured for reducing the possibility of damage to blades integral to a turbine power plant. 
     BACKGROUND OF THE INVENTION 
     Turbine power plants, such as gas turbines, are used in a variety of useful applications. Aviation, shipping, power generation, and chemical processing have all benefited from turbine power plants of various designs. 
     Turbine power plants (i.e., combustion turbines) typically have a compressor section for compressing inlet air, a combustion section for combining the compressed inlet air with fuel and oxidizing that fuel, and a turbine section where the energy from the hot gas produced by the oxidation of the fuel is converted into work. Usually, natural gas (mostly methane), kerosene, or synthetic gas (such as carbon monoxide) is fed as fuel to the combustion section, but other fuels could be used. The rotor—defined by a rotor shaft, attached turbine section rotor blades, and attached compressor section rotor blades—mechanically powers the compressor section and, in some cases, a compressor used in a chemical process or an electric generator. The exhaust gas from the turbine section can used to achieve thrust; it also can be a source of heat and energy, or, in some cases, it is discarded. 
     It is known that materials such as water can also be added when the turbine power plant is operating to augment the power output capability of a turbine power plant above the output achievable with normally humidified or ambient air. Such a procedure is known as wet compression. Wet compression enables power augmentation in turbine power plants by reducing the work required for compression of the inlet air. This thermodynamic benefit is realized within the compressor of a gas turbine through “latent heat intercooling” where water (or some other appropriate liquid) added to the air inducted into the compressor cools that air through evaporation as the air with the added water is being compressed. The added water can be conceptualized as an “evaporative liquid heat sink”. 
     The wet compression approach thus saves an incremental amount of work (which would have been needed to compress air not containing the added water) and makes the incremental amount of work available to either drive the load attached to the gas turbine (in the case of a single shaft machine) or to increase the compressor speed to provide more mass flow (which can have value in both single shaft and multiple shaft machines). 
     Various methods and apparatuses have been employed to facilitate the introduction of fluid (i.e., water) to the working fluid of turbine power plants so as to realize the benefits of wet compression. One such known method involves the circumferential introduction or staging of water to the turbine power plant. While effective to a certain degree, the circumferential staging of water in turbine power plants often results in the introduction of different forcing functions into the components of the turbine power plant (depending on how many spray arms are being employed) which could lead to damage of these components such as the blades of the turbine power plant. 
     With the forgoing problems and concerns in mind, it is the general object of the present invention to provide a radial staging of a liquid injection system configured for reducing the possibility of damage to blades and other components that are integral to a turbine power plant. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, a liquid injection system for a turbine power plant includes a hub configured to be coupled to an air intake case of a turbine power plant. An annular ring assembly is spaced radially outwardly from the hub. A plurality of spray bars is spoked between and circumferentially spaced about the hub and the annular ring. The spray bars each include an elongated body portion having an inner end coupled to the hub and an outer end coupled to the annular ring assembly. The spray bars each have at least two nozzle assemblies spaced from one another along the body portion. The spray bars each define at least two liquid supply manifolds each having an inlet at the annular ring assembly and an outlet at an associated nozzle assembly. The liquid supply manifolds each are configured to supply liquid to an associated at least one of the nozzle assemblies. 
     In another aspect of the present invention, a method of injecting liquid within a turbine power plant includes providing a hub configured to be coupled to an air intake case of a turbine power plant, an annular ring assembly spaced radially outwardly from the hub, and a plurality of spray bars spoked between and circumferentially spaced about the hub and the annular ring. The spray bars each include an elongated body portion having an inner end coupled to the hub and an outer end coupled to the annular ring assembly. The spray bars each have at least two nozzle assemblies spaced from one another along the body portion, and the spray bars each define at least two liquid supply manifolds each having an inlet at the annular ring assembly and an outlet at an associated nozzle assembly. Liquid is directed during a stage one actuation to each of the spray bars such that through each of the spray bars the liquid flows through a first one of the manifolds to energize a first one of the nozzle assemblies. Liquid is directed during a stage two actuation to each of the spray bars such that through each of the spray bars the liquid further flows through a second one of the manifolds to energize a second one of the nozzle assemblies. 
     In a further aspect of the present invention, a method of injecting liquid within a turbine power plant includes providing a hub configured to be coupled to an air intake case of a turbine power plant, an annular ring assembly spaced radially outwardly from the hub, and a plurality of spray bars spoked between and circumferentially spaced about the hub and the annular ring. The spray bars each include an elongated body portion having an inner end coupled to the hub and an outer end coupled to the annular ring assembly. The spray bars each have at least two nozzle assemblies spaced from one another along the body portion, and the spray bars each define at least two liquid supply manifolds each having an inlet at the annular ring assembly and an outlet at an associated nozzle assembly. Liquid is selectively directed through the liquid supply manifolds to operate the nozzle assemblies independently or in combination with one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a turbine power plant incorporating a liquid injection system according to an embodiment of the present invention. 
         FIG. 2  is an enlarged partial elevational view of the liquid injection system of  FIG. 1 . 
         FIG. 3A  is a perspective view of the annular ring and spray bars of the liquid injection system. 
         FIG. 3B  is an enlarged end view of a portion of the annular ring. 
         FIG. 3C  is an enlarged side view of a portion of the annular ring. 
         FIG. 4  is an exploded view of a spray bar. 
         FIG. 5  is a cross-sectional view of a spray bar. 
         FIG. 6  is a perspective view of a spray bar. 
         FIG. 7A  schematically illustrates a fluid spray direction outwardly from a spray bar in accordance with the present invention. 
         FIG. 7B  schematically illustrates another fluid spray direction outwardly from a spray bar. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates a cross-sectional view of a turbine power plant  10  embodying the present invention. As shown in  FIG. 1 , an air intake end  12  receives a working fluid (i.e., ambient air) therethrough, which passes serially through a compressor, combustion and turbine fan sections as commonly known in the art. 
     As also shown in  FIG. 1 , a liquid injection system  18  in accordance with the present invention is located in an area in front of the turbine inlet case and behind the package intake. 
     The liquid injection system  18  preferably is oriented closely to compressor sections,  16  and  17 . By disposing the liquid injection system  18  closely to the compressor sections  16  and  17 , the liquid injection system  18  largely avoids having the water-infused working fluid from impacting a large number of static structures prior to the compressor sections  16  and  17 . In this manner, the positioning of the liquid injection system  18  closely to the compressor sections  16  and  17  of the turbine power plant  10  correspondingly reduces the chance of damage to compressors and the like oriented downstream of the liquid injection system. 
       FIG. 2  illustrates an enlarged elevational or side view of the upper half of the liquid injection system  18 . The liquid injection system  18  is disposed in an annular ring  20 , which is concentrically aligned with the longitudinal operating axis L of the turbine power plant  10 . The general purpose of the liquid injection system  18  is to provide a selective and measured amount of water to the working fluid (i.e., air), which is being drawn through the inlet or air intake end  12 . 
     Indeed, it is another aspect of the present invention that the liquid injection system  18  operates in such a manner that only a single forcing function is produced. That is, the liquid injection system  18  embodying the present invention is capable of producing an approximately uniform annulus of water infusion to the working fluid, concentrically aligned with the operating axis L of the turbine power plant  10 , as will be described in more detail later. In this way, the liquid injection system  18  embodying the present invention avoids the localized high pressure areas that are common in known circumferential injection systems. 
     With reference to  FIGS. 3A through 3C , the liquid injection system  18  for a turbine power plant comprises a hub  22  configured to be coupled to an air intake case of a turbine power plant. An annular ring assembly  24  is spaced radially outwardly from the hub  22 . A plurality of spray bars  26  are spoked between and circumferentially spaced about the hub  22  and the annular ring assembly  24 . The spray bars  26  each include an elongated body portion  28  having an inner end  30  coupled to the hub  22  and an outer end  32  coupled to the annular ring assembly  24 . The spray bars  26  each have a plurality of nozzle assemblies  34  spaced from one another along the body portion  28 . As shown in  FIGS. 2 and 5 , the spray bars  26  each define a plurality of liquid supply manifolds  36   a ,  36   b ,  36   c  each having an inlet  38  at the annular ring assembly  24  and an outlet  40  at an associated nozzle assembly  34 . The plurality of liquid supply manifolds  36   a ,  36   b ,  36   c  each are configured to supply liquid to an associated at least one of the plurality of nozzle assemblies  34 . 
     Each of the spray bars  26  has an adapter cap  42  nested in the annular ring assembly  24 . As best seen in the exploded view of  FIG. 4  and the cross-sectional view of  FIG. 5 , the spray bars  26  are formed to have an interlocking front and rear pairing  44  and  46  respectively. The front and rear parings  44  and  46  are preferably both releasably fixed to the adapter cap  42 . 
     As shown in  FIGS. 4 ,  5  and  6 , four nozzle assemblies  34  are preferably located in cavities  48  formed in the front pairing  44  of the spray bars  26 . Although four nozzle assemblies  34  are shown on each of the spray bars  26  by way of example, it should be understood that two or more nozzle assemblies  34  can be used on each spray bar without departing from the scope of the present invention. These nozzle assemblies  34  are themselves each supplied with a desired liquid (e.g., water) via a plurality of manifolds extending through the front pairing  44 . In particular, two of the nozzle assemblies  34  are preferably supplied with liquid via single-nozzle manifolds  36   a  and  36   b , while the remaining two nozzle assemblies  34  are tied to a common manifold  36   c . Each of the manifolds  36   a ,  36   b ,  36   c  may be selectively employed by a conventional fluid controller  50  to provide varying degrees of liquid injection to the working fluid of the turbine power plant  10 , as will be described in more detail later. In other words, the nozzle assemblies  34  on a spray bar  26  can be independently operated or operated in combination with one another. 
     As best shown in  FIG. 3B , three fluid supply lines  52  are each coupled to the adapter caps  42  about the annular ring assembly  24 . More specifically the three fluid supply lines  52  each communicate with a respective different one of the three manifolds  36   a ,  36   b ,  36   c  via the inlets  38 . When selectively actuated by the fluid controller  50 , one or more of the fluid supply lines  52  carries fluid to the nozzle assemblies  34  depending on whether the liquid injection system  18  is under stage 1, stage 2, stage 3 or stage 4 actuation. 
     As shown in  FIG. 3A , there are preferably eighteen spray bars  26  radially disposed about the annular ring assembly  24 . Although eighteen spray bar  26  are shown by way of example, it should be understood that a fewer or greater number of spray bars can be used. As employed heretofore in the art, it has been known to selectively energize only certain spray bars in a staggered fashion such that all of the nozzle assemblies supported by each of the energized spray bars are activated at the same time. Thus, with known systems, the first, fourth seventh, and so on, spray bars are selectively employed, and each of these spray bars cause all of their imbedded nozzle assemblies to inject liquid at the same time. Thus, as mentioned above, a drawback of known systems is that the selective employment of discreet spray bars creates areas of localized higher pressure about the operational axis L. 
     The present invention seeks to overcome the drawbacks of such known systems by employing the spray bars  26  in a manner, which harmonizes the pressure regimen and water dispersion about the operational axis L. In this regard, the liquid injection system  18  is configured to selectively direct liquid through one or more of the manifolds  36   a ,  36   b ,  36   c  of each of the spray bars  26  to energize associated nozzle assemblies  34  as warranted by environmental conditions and/or power demands. 
     In particular, and as best seen in  FIG. 5 , the liquid injection system  18  in accordance with the present invention is configured to energize the nozzle assemblies  34  of the spray bars  26  in such a manner that substantially uniform annular zones of water are injected by the selective operation of the manifolds  36   a ,  36   b ,  36   c . That is, as shown in  FIG. 5 , it is possible for the fluid controller  50  to have only the stage 1 nozzle assemblies actuated in each of the eighteen spray bars  26  located about the annular ring assembly  24 . By actuating only the manifold  36   a  which controls the stage 1 nozzle assemblies  34  in each of the spray bars  26 , it is possible to produce annular zones of water which are substantially uniform in density about the operational axis L. 
     Still further, when additional power is required, the fluid controller  50  of the liquid injection system  18  is configured to selectively actuate both the manifold  36   a  as well as the manifold  36   b , thus activating both stage 1 and stage 2 nozzle assemblies  34 . As shown in  FIG. 5 , when both the manifolds  36   a  and  36   b  are actuated, two sets of nozzle assemblies  34  on each of the spray bars  26  inject liquid into the working fluid of the turbine power plant  10 . Doing so obviously increases the size of the annular zones created about the operational axis L, but this zone is still substantially uniform. 
     It is also possible for the fluid controller  50  to activate the stage 3 nozzle assemblies  34  by simultaneously actuating manifolds  36   a ,  36   b  and  36   c . While employing the stage 3 nozzle assemblies  34  causes all of the nozzle assemblies  34  in each of the spray bars  26  to be actuated, the stage 3 actuation varies the pressure through the common manifold  36   c . Thus, during stage 3 actuation, it is possible to vary the output of the nozzle assemblies  34  by varying the amount of liquid permitted to flow through the common manifold  36   c.    
     Finally, in a stage 4 actuation, all of the nozzle assemblies  34  in each of the spray bars  26  are simultaneously actuated by the fluid controller  50 ; however, the common manifold  36   c  is operated by the fluid controller at its maximum capacity. Thus, a stage 4 actuation corresponds to maximum liquid injection by the liquid injection system  18  embodying the present invention. 
     By supplying separate manifolds  36   a ,  36   b  and  36   c  to discreet nozzle assemblies  34  in each of the spray bars  26 , the liquid injection system  18  embodying the present invention is capable of actuating discreet, radial sections of each of the spray bars  26 —in stark contrast to known systems. Moreover, by selectively actuating only discreet nozzle assemblies  34  on each of the spray bars  26 , substantially uniform annular zones of water are created about the operational axis L, and hence, localized pressure distortions about the operational axis L are effectively eliminated. 
       FIGS. 7A and 7B  illustrate by way of example different angular orientations of the nozzle assemblies in relationship to the spray bar. With reference to  FIG. 7A , for example, a spray bar with front pairing  44  and rear pairing  46  has nozzle assemblies orientated to spray in direction  54  oriented 25 degrees rearwardly relative a sideward direction. With reference to  FIG. 7B , for example, a spray bar with front pairing  44  and rear pairing  46  has nozzle assemblies orientated to spray in direction  56  oriented 25 degrees forwardly relative to a sideward direction. Although  FIGS. 7A and 7B  show two spray directions by way of example, it should be understood that the nozzle assemblies can be oriented on the spray bars to spray in other forward or rearward directions without departing from the scope of the present invention. Moreover, the spray directions can be angled to be in upward and downward directions (i.e. angled in directions into and out of the page as shown in  FIGS. 7A and 7B . For example, the nozzle assemblies can be angled 25 degrees downwardly or 25 degrees upwardly or at any other downward or upward direction. 
     As will be recognized by those of ordinary skill in the pertinent art, numerous modifications and substitutions can be made to the above-described embodiments of the present invention without departing from the scope of the invention. Accordingly, the preceding portion of this specification is to be taken in an illustrative, as opposed to a limiting sense.