Abstract:
A cooling fluid feed system for a turbine engine for directing cooling fluids from a compressor, through one or more impellers, and into row one turbine vanes and one or more rows of turbine blades for increasing the cooling capacity of the turbine vanes and blades. Such a configuration increases cooling capacity, which in turn increases the capacity for growth within the turbine engine, creates a larger cooling fluid to gas side pressure differential and reduces amount of bleed off of cooling fluids from the compressor, thereby increasing efficiency of the turbine engine.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is a continuation-in-part application of U.S. patent application Ser. No. 11/526,255, filed Sep. 22, 2006, which is incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention is directed generally to turbine engines, and more particularly to cooling fluid feed systems in turbine engines. 
     BACKGROUND 
     Typically, gas turbine engines include a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, and a turbine blade assembly for producing power. Combustors often operate at high temperatures that may exceed 2,500 degrees Fahrenheit. Typical turbine combustor configurations expose turbine blade assemblies to these high temperatures. As a result, turbine blades and turbine vanes must be made of materials capable of withstanding such high temperatures. Turbine blades, vanes and other components often contain cooling systems for prolonging the life of these items and reducing the likelihood of failure as a result of excessive temperatures. 
     Typically, turbine vanes extend radially inward from a vane carrier and terminate within close proximity of a rotor assembly. The turbine vanes typically include a plurality of cooling channels positioned in internal aspects of the turbine vanes. A controlling factor in the design of the internal cooling channels is the pressure differential between the internal cooling channels and the outer combustor gases. Often, the pressure differential is too small to enable film cooling orifices to be used effectively. As a result, the capacity to cool the turbine vanes is limited and thus, the operating range and potential growth of the turbine engine are thereby limited as well. Thus, a need exists for a more efficient cooling fluid feed system design for row one turbine vanes to provide pressurized cooling fluids to enable turbine engine growth and increased operating range. 
     SUMMARY OF THE INVENTION 
     This invention relates to a cooling fluid feed system for a turbine engine for supplying cooling fluids to row one turbine vanes and supplying cooling fluids to a first turbine blade row or a second turbine blade row, or both. The cooling fluid feed system may include a first row turbine vane impeller for increasing the pressure of cooling fluids supplied to the row one turbine vanes. The cooling fluid feed system may also include a turbine blade impeller for increasing the pressure of cooling fluids supplied to the first or second rows of turbine blades, or both. Increasing the pressure of the cooling fluids supplied to the row one turbine vanes may reduce the operating temperature of the vanes by enabling turbine vane cooling systems to use more efficient cooling channel designs, such as by incorporating film cooling holes within internal cooling channels. The cooling fluids may be, but are not limited to, cooling air. 
     The turbine engine may include one or more combustors positioned upstream from a rotor assembly. The rotor assembly may include one or more rows of turbine blades. In one embodiment, first and second rows of turbine blades may extend radially outward from a rotor. The turbine engine may also include a compressor positioned upstream from the combustor. A first row of turbine vanes may be attached to a vane carrier. The turbine vanes may extend radially inward and may terminate proximate to the rotor assembly upstream of the first row of turbine blades. A first row turbine vane impeller may be in fluid communication with cooling systems positioned internally within the turbine vanes in the first row of turbine vanes for increasing the pressure of cooling fluids flowing from the compressor. The first row turbine vane impeller may have a cross-sectional area that increases moving radially outward. One or more concentric bores may extend from the compressor to the first row turbine vane impeller to direct cooling fluids from the compressor to the first row turbine vane impeller. The first row turbine vane impeller may be formed from a plurality of radially extending channels positioned in close proximity to a first blade rotor. A plurality of turning guide vanes may be positioned radially inward from the first row turbine vane impeller to direct cooling fluids from the concentric bore into the first row turbine vane impeller. 
     The turbine engine may also include a turbine blade impeller positioned between first and second blade rotors that are attached to and support the first and second rows of turbine blades. The turbine blade impeller may be attached to at least one of the first and second blade rotors with a circumferential slot radially inward from the turbine blade impeller. The turbine blade impeller may be formed from a plurality of radially extending channels. The turbine engine may include a first cooling fluid hole in fluid communication with the first row of turbine blades and a second cooling fluid hole in fluid communication with the second row of turbine blades. A mid-stage bleed fluid channel may be in fluid communication with a mid-stage bleed fluid supply and the turbine blade impeller. A plurality of turning guide vanes may be positioned in the mid-stage fluid channel to direct cooling fluids from the mid-stage bleed fluid channel to the turbine blade impeller. 
     During use, cooling fluids, such as, but not limited to, air, may flow from the compressor, through the concentric bore, through the turning guide vanes and into the first row turbine vane impeller. The cooling fluids may be pumped radially outward within the first row turbine vane impeller to the vane cooling fluid manifold. The vane cooling fluid manifold may function as a diffuser plenum to create the maximum dynamic pressure head and to create the maximum relative velocity head of the cooling fluids. The higher the pressure head, the greater the potential for the cooling fluids to adequately cool the row one turbine vanes. The cooling fluids may flow from the vane cooling fluid manifold to the turbine vane cooling systems of the row one turbine vanes. Thus, the cooling fluids used to cool the row one turbine vanes flow radially outward through the turbine vanes. 
     Cooling fluids may also flow through the mid-stage bleed fluid channel, through the turning guide vanes and into the turbine blade impeller. The cooling fluids may be pressurized in the impeller and may be discharged through the first and second cooling fluid holes and into the first and second turbine blade rows, respectively. 
     An advantage of this invention is that the row one turbine vane impeller increases the cooling fluid to gas side pressure differential such that a more effective cooling scheme may be used in the cooling system positioned internally within the turbine vanes. In particular, there may be a pressure differential developed that is sufficient to use both leading edge film cooling holes together with film cooling holes in other locations. Use of such effective cooling techniques enables a higher firing temperature to be used in the combustor, thereby resulting in greater turbine engine output and creating the possibility of turbine engine growth. 
     Another advantage of this invention is that the combustor may be operated at a decreased pressure drop across the combustor, thereby resulting in higher turbine inlet operating pressure, overall higher working pressure ratio across the turbine and higher engine power output. 
     Yet another advantage of this invention is that use of mid-stage bleed air for turbine cooling reduces the cooling fluid bleed off at higher compressor stages. 
     Thus, less work is required to be conducted on the input air, which equates to higher turbine cycle efficiency. 
     Another advantage of this invention is that use of mid-stage bleed air for turbine cooling reduces the cooling fluid bleed off at higher compressor stages, thereby resulting in more working fluid flowing through the combustor, resulting in a higher power output. 
     These and other embodiments are described in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention. 
         FIG. 1  is a cross-sectional side view of a portion of a turbine engine including a cooling fluid feed system of this invention. 
         FIG. 2  is a detailed view of a portion of the turbine engine shown in  FIG. 1  at line  2 - 2 . 
         FIG. 3  is an axial, cross-sectional view of a turbine blade impeller taken at section lines  3 - 3  in  FIG. 2 . 
         FIG. 4  is an axial, cross-sectional view of a turbine blade impeller taken at section lines  4 - 4  in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIGS. 1-4 , this invention is directed to a cooling fluid feed system  10  for a turbine engine  8  for supplying cooling fluids to row one turbine vanes  12  and supplying cooling fluids to a first turbine blade row  14  or a second turbine blade row  16 , or both. The cooling fluid feed system  10  may include a first row turbine vane impeller  18  for increasing the pressure of cooling fluids supplied to the row one turbine vanes  12  so that more efficient cooling schemes may be used in the turbine vanes  12 . The cooling fluid feed system  10  may also include a turbine blade impeller  20  for increasing the pressure of cooling fluids supplied to the first or second rows of turbine blades  14 ,  16 , or both. Increasing the pressure of the cooling fluids supplied to the row one turbine vanes  12  may reduce the operating temperature of the vanes  12  by enabling turbine vane cooling systems  22  to better incorporate film cooling holes with internal cooling channels. The cooling fluids may be, but are not limited to, cooling air. 
     As shown in  FIG. 1 , the turbine engine  8  may include a rotor assembly  24  positioned radially inward from a vane carrier  26  and the turbine vanes  12 . The rotor assembly  24  may include first and second rows of turbine blades  14 ,  16 , or more, extending radially outward from the rotor assembly  24 . As shown in  FIG. 1 , the turbine blades  14 ,  16  may be assembled into rows, which are also referred to as stages. The turbine engine  8  may also include one or more combustors  28  positioned upstream from the rotor assembly  24 . The rotor assembly  24  may be configured to enable the rotor  30  to rotate relative to the vane carrier  26  and turbine vanes  12 . The turbine engine  8  may also include a compressor  32  positioned upstream from the combustor  28 . 
     The cooling fluid feed system  10  may include a first row turbine vane impeller  18  positioned proximate to a first blade rotor  34 . The turbine vane impeller  18  may be a centrifugal stage impeller that may induce a solid body rotating pumping effect that may raise the cooling fluid pressure for cooling fluids supplied to the row one turbine vanes  12 . In at least one embodiment, as shown in  FIG. 3 , the first row turbine vane impeller  18  may be formed from a plurality of radially extending channels  36  creating a pumping action due to solid body rotation principal. The radially extending channels  36  may be formed from curved channels  36  whose cross-sectional areas increase moving radially outward. The curved channels  36  may be curved away from the direction of rotation and curved generally in a plane orthogonal to a rotational axis of the rotor assembly  24 . In particular, as shown in  FIG. 3 , a leading edge  64  of the curved channels  36  may be generally concave. The curved channels  36  may be defined by curved ribs  66 . The curved ribs  66  may have cross-sectional areas that increase, decrease or remain unchanged moving radially outward. 
     The first row turbine vane impeller  18  may receive cooling fluids from the compressor  32  as compressor exhaust through one or more concentric bores  38 . The concentric bore  38  may be any appropriate size. One or more turning guide vanes  40  may be positioned to direct cooling fluids from the concentric bore  38  to the first row turbine vane impeller  18 . One or more vane cooling fluid manifolds  42  may be positioned between the row one turbine vanes  12  and the first row turbine vane impeller  18  for collecting cooling fluids flowing from the first row turbine vane impeller  18 . 
     The cooling fluid feed system  10  may also include a turbine blade impeller  20  for pressurizing cooling fluids being sent to the first or second turbine blade rows  14 ,  16  or both. The turbine blade impeller  20  may be formed from a plurality of radially extending channels  44  positioned between the first blade rotor  34  and a second blade rotor  46 . The first and second blade rotors,  34 ,  46  are attached to and support the first and second rows of turbine blades  14 ,  16 , respectively. The cooling fluid feed system  10  may also include one or more first cooling fluid holes  48  in fluid communication with the first row of turbine blades  14  and one or more second cooling fluid holes  50  in fluid communication with the second row of turbine blades  16 . Each turbine blade  14 ,  16  may include a hole  48 ,  50 , respectively. The rotor assemblies  24  may have different configurations and may include a variety of numbers of turbine blades, such as for example and not by way of limitation, sixteen or thirty two blades. Each blade may be supplied with a single cooling hole,  48  or  50  in communication with the turbine blade impeller  20 . 
     The turbine blade impeller  20  may be attached to the first and second blade rotors  34 ,  36  through one or more circumferential slots  52  positioned radially inward from turbine blade impeller  20 . The turbine blade impeller  20  may also be attached radially outward of the impeller at the rim  54  with an interference fit, such as a snap fit. In at least one embodiment, as shown in  FIG. 4 , the turbine blade impeller  20  may be formed from a plurality of radially extending channels  68  creating a pumping action due to solid body rotation principal. The radially extending channels  68  may be formed from curved channels  70  whose cross-sectional areas increase moving radially outward. The curved channels  70  may be curved away from the direction of rotation. In particular, as shown in  FIG. 4 , a leading edge  72  of the curved channels  70  may be generally concave. The curved channels  70  may be curved away from the direction of rotation and curved generally in a plane orthogonal to a rotational axis of the rotor assembly  24 . The curved channels  70  may be defined by curved ribs  74 . The curved ribs  74  may have cross-sectional areas that increase, decrease or remain unchanged moving radially outward. 
     The cooling fluid feed system  10  may include a mid-stage bleed fluid channel  56  in fluid communication with a mid-stage bleed fluid supply and the turbine blade impeller  20 . The mid-stage fluid channel  56  may have any appropriate configuration. 
     One or more turning guide vanes  58  may be positioned to direct cooling fluids from the mid-stage bleed fluid channel  56  to the turbine blade impeller  20  through the channel formed between the first and second blade rotors  34 ,  46 . The turning guide vanes  58  may be mounted on a bore of the second blade rotor  46 . 
     During use, cooling fluids, such as, but not limited to, air, may flow from the compressor  32 , through the concentric bore  38 , through the turning guide vanes  40  and into the first row turbine vane impeller  18 . The cooling fluids may be pumped radially outward within the first row turbine vane impeller  18  to the vane cooling fluid manifold  42 . The radially extending channels  36  increase the pressure of cooling fluids out of the first row turbine vane impeller  18 . The vane cooling fluid manifold  42  may function as a diffuser plenum to create the maximum pressure head and to create a relative velocity head of the cooling fluids. The higher the pressure head, the greater the potential for the cooling fluids to adequately cool the row one turbine vanes  12 . The cooling fluids may flow from the vane cooling fluid manifold  42  to the turbine vane cooling systems  22  of the row one turbine vanes  12 . Thus, the cooling fluids used to cool the row one turbine vanes  12  flow radially outward through the turbine vanes  12 . 
     Cooling fluids may also flow through the mid-stage bleed fluid channel  56 , through the turning guide vanes  58  and into the turbine blade impeller  20 . The cooling fluids may be pressurized in the impeller  20  in the curved channels  70  and may be discharged through the first and second cooling fluid holes  48 ,  50  and into the first and second turbine blade rows  14 ,  16 , respectively. 
     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.