Abstract:
A turbine blade cooling system according to an embodiment includes: a first arcuate turn for redirecting a first flow of gas flowing through a first channel of a turbine blade into a central plenum of the turbine blade; and a second arcuate turn for redirecting a second flow of gas flowing through a second channel of the turbine blade into the central plenum of the turbine blade, wherein the first and second arcuate turns reduce impingement of the first flow of gas and the second flow of gas in the central plenum of the turbine blade.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to co-pending U.S. application Ser. No. ______, GE docket numbers 282167-1, 282169-1, 282171-1, 283464-1, 283467-1, 283463-1, 283462-1, and 284160-1, all filed on ______. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The disclosure relates generally to turbine systems, and more particularly, to reducing pressure loss in a multi-wall turbine blade cooling circuit. 
         [0003]    Gas turbine systems are one example of turbomachines widely utilized in fields such as power generation. A conventional gas turbine system includes a compressor section, a combustor section, and a turbine section. During operation of the gas turbine system, various components in the system, such as turbine blades, are subjected to high temperature flows, which can cause the components to fail. Since higher temperature flows generally result in increased performance, efficiency, and power output of the gas turbine system, it is advantageous to cool the components that are subjected to high temperature flows to allow the gas turbine system to operate at increased temperatures. 
         [0004]    Turbine blades of a gas turbine system typically contain an intricate maze of internal cooling channels. The cooling channels receive air from the compressor of the gas turbine system and pass the air through the internal cooling channels to cool the turbine blades. The feed pressure of the air passed through the cooling channels is generally at a premium, since the air is bled off of the compressor. To this extent, it is useful to provide cooling channel that reduce non-recoverable pressure loss; as pressure losses increase, a higher feed pressure is required to maintain an adequate gas-path pressure margin (back-flow margin). Higher feed pressures result in higher leakages in the secondary flow circuits (e.g., in rotors) and higher feed temperatures. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    A first aspect of the disclosure provides a turbine blade cooling system, including: a first arcuate turn for redirecting a first flow of gas flowing through a first channel of a turbine blade into a central plenum of the turbine blade; and a second arcuate turn for redirecting a second flow of gas flowing through a second channel of the turbine blade into the central plenum of the turbine blade, wherein the first and second arcuate turns reduce impingement of the first flow of gas and the second flow of gas in the central plenum of the turbine blade. 
         [0006]    A second aspect of the disclosure provides turbine blade, including: a cooling system, the cooling system including: a cooling system disposed within the turbine blade, the cooling system including: a first arcuate turn for redirecting a first flow of gas flowing through a first channel of the turbine blade into a central plenum of the turbine blade; and a second arcuate turn for redirecting a second flow of gas flowing through a second channel of the turbine blade into the central plenum of the turbine blade; wherein the first and second arcuate turns reduce impingement of the first flow of gas and the second flow of gas in the central plenum of the turbine blade. 
         [0007]    A third aspect of the disclosure provides a turbine bucket, including: a shank; a multi-wall blade coupled to the shank; and a cooling system disposed within the multi-wall blade, the cooling system including: a first arcuate turn for redirecting a first flow of gas flowing through a first channel into a central plenum of the blade; a second arcuate turn for redirecting a second flow of gas flowing through a second channel into the central plenum of the blade, the first flow of gas and the second flow of gas combining in the central plenum; wherein the first and second arcuate turns reduce impingement of the first flow of gas and the second flow of gas in the central plenum. 
         [0008]    The illustrative aspects of the present disclosure solve the problems herein described and/or other problems not discussed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawing that depicts various embodiments of the disclosure. 
           [0010]      FIG. 1  shows a perspective view of a turbine bucket including a blade, according to embodiments. 
           [0011]      FIG. 2  is a partial cross-sectional view of the blade of  FIG. 1 , taken along line  2 - 2  in  FIG. 1 , according to embodiments. 
           [0012]      FIG. 3  depicts a pressure loss reducing structure with shaped return channels, according to embodiments. 
           [0013]      FIG. 4  is a partial cross-sectional view of the blade of  FIG. 1  depicting a pressure loss reducing structure with shaped return channels, according to embodiments. 
           [0014]      FIG. 5  depicts a pressure loss reducing structure with turning vanes, according to embodiments. 
           [0015]      FIG. 6  depicts a pressure loss reducing structure with turning vanes, according to embodiments. 
           [0016]      FIG. 7  is a partial cross-sectional view of the blade of  FIG. 1  depicting a pressure loss reducing structure with turning vanes in the return channels, according to embodiments. 
       
    
    
       [0017]    It is noted that the drawing of the disclosure is not to scale. The drawing is intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawing, like numbering represents like elements between the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    As indicated above, the disclosure relates generally to turbine systems, and more particularly, to reducing pressure loss in a multi-wall turbine blade cooling circuit. 
         [0019]    Turning to  FIG. 1 , a perspective view of a turbine bucket  2  is shown. The turbine bucket  2  includes a shank  4  and a blade  6  (e.g., a multi-wall blade) coupled to and extending radially outward from the shank  4 . The blade  6  includes a pressure side  8  and an opposed suction side  10 . The blade  6  further includes a leading edge  12  between the pressure side  8  and the suction side  10 , as well as a trailing edge  14  between the pressure side  8  and the suction side  10  on a side opposing the leading edge  12 . 
         [0020]    The shank  4  and blade  6  may each be formed of one or more metals (e.g., steel, alloys of steel, etc.) and can be formed (e.g., cast, forged or otherwise machined) according to conventional approaches. The shank  4  and blade  6  may be integrally formed (e.g., cast, forged, three-dimensionally printed, etc.), or may be formed as separate components which are subsequently joined (e.g., via welding, brazing, bonding or other coupling mechanism). 
         [0021]      FIG. 2  is a partial cross-sectional view of the blade  6  taken along line  2 - 2  of  FIG. 1 , depicting a cooling arrangement  16  including a plurality of cooling circuits, according to embodiments. In this example, the cooling arrangement  16  includes an internal 2-pass serpentine suction side (SS) cooling circuit  18  on the suction side  10  of the blade  6  as well as an internal 2-pass serpentine pressure side (PS) cooling circuit  20  on the pressure side  8  of the blade  6 . Although described in terms of a 2-pass serpentine cooling circuit, it should be apparent to those skilled in the art that the pressure loss reducing structures of the present disclosure (described below) may be used in conjunction with other types of serpentine (e.g., 3-pass, 4-pass, etc.) and/or non-serpentine cooling circuits in which “spent” cooling air from a plurality of flow channels is collected for redistribution to other areas of the blade  6 , shank  4 , and/or other portions of the bucket  2  for cooling purposes. Further, the pressure loss reducing structures may be used in other sections of the blade  6 , shank  4 , and/or other portions of the bucket  2  where there is a need for gathering a plurality of gas flows into a single gas flow for redistribution. 
         [0022]    The SS cooling circuit  18  includes a feed channel  22  for directing a flow of cooling gas  24  (e.g., air) radially outward toward a tip area  48  ( FIG. 1 ) of the blade  6  along the suction side  10  of the blade  6 . In  FIG. 2 , the flow of cooling gas  24  is depicted as flowing out of the page. After passing through a turn (not shown), a flow of “spent” cooling gas  26  is directed back towards the shank  4  of the blade  6  through a return channel  28 . In  FIG. 2 , the flow of cooling gas  26  is depicted as flowing into of the page. 
         [0023]    The PS cooling circuit  20  includes a feed channel  32  for directing a flow of cooling gas  34  (e.g., air) radially outward toward the tip area  48  ( FIG. 1 ) of the blade  6  along the pressure side  8  of the blade  6 . After passing through a turn (not shown), a flow of “spent” cooling gas  36  is directed back towards the shank  4  of the blade  6  through a return channel  38 . In  FIG. 2 , the flow of cooling gas  34  is depicted as flowing out of the page, while the flow of cooling gas  36  is depicted as flowing into of the page. 
         [0024]    According to embodiments, referring to  FIGS. 3 and 5 , together with  FIG. 2 , a pressure loss reducing structure  40  ( FIG. 3 ),  50  ( FIG. 5 ) is provided for combining the flow of cooling gas  26  flowing through the return channel  28  of the SS cooling circuit  18  with the flow of cooling gas  36  flowing through the return channel  38  of the PS cooling circuit  20 , to form a single, combined flow of cooling gas  42  within a central plenum  44 . This may be achieved with reduced pressure loss by preventing impingement of the flows of cooling gas  26 ,  36  as the flows enter the central plenum  44 . The pressure loss reducing structure  40  is configured to turn the flows of cooling gas  26 ,  36  before the flows of cooling gas  26 ,  36  enter the central plenum  44 . This may be achieved, for example, by shaping ( FIG. 3 ) the return channels  28 ,  38  and/or by using turning vanes ( FIG. 4 ) in the return channels  28 ,  38 , such that the flows of cooling gas  26 ,  36  are substantially parallel to one another when combined in the central plenum  44 . Advantageously, the redirected flows of cooling gas  26 ,  36  flow into the central plenum  44  with reduced impingement and associated pressure loss. 
         [0025]    In the blade  6 , the flow of cooling gas  42  passes radially outward through the central plenum  44  (out of the page in  FIG. 2 ). From the central plenum  44 , the flow of cooling gas  42  may be redistributed, for example, to a leading edge cavity  46  located in the leading edge  12  of the blade  6  to provide impingement cooling. Alternatively, or in addition, the flow of cooling gas  42  may be redistributed to the tip area  48  ( FIG. 1 ) of the blade  6 . The flow of cooling gas  42  may also be provided to other locations within the blade  6 , shank  4 , and/or other portions of the bucket  2  for purposes of convention cooling. Still further, the flow of cooling gas  42  may be used to provide film cooling of the exterior surfaces of the blade  6 . Depending on the location of the pressure loss reducing structure  40 ,  50  in the blade  6 , the flow of cooling gas  42  may be also be redistributed, for example, to cooling channels/circuits at the trailing edge  14  of the blade  6 . Any number of pressure loss reducing structures  40 ,  50  may be employed within the blade  6 . 
         [0026]    A first embodiment of a pressure loss reducing structure  40  is depicted in  FIG. 3 . As shown in  FIG. 3 , the flow of cooling gas  26  flowing through the return channel  28  of the SS cooling circuit  18  flows through the return channel  28  in a first direction (arrow A) to a first arcuate turn  60  of the pressure loss reducing structure  40 , which has an arcuate end wall  62 . The flow of cooling gas  26  flows from the return channel  28  into the first arcuate turn  60  through an inlet I 1 . The flow of cooling gas  26  is redirected (arrow B) by the arcuate end wall  62  and a peaked junction  80  formed by the distal ends of the arcuate end wall  62  and an arcuate end wall  72  of a second arcuate turn  70  (described below) toward and into (arrow C) the central plenum  44  through an outlet O 1 , forming a portion of the flow of cooling gas  42 . The return channel  28  and the central plenum  44  are separated by a rib  66 . As shown in  FIG. 3 , the flow of cooling gas  26  flows around an end section  68  of the rib  66 . 
         [0027]    Also depicted in  FIG. 3  is a second arcuate turn  70  of the pressure loss reducing structure  40 . The flow of cooling gas  36  flowing through the return channel  38  of the PS cooling circuit  20  flows through the return channel  38  in a first direction (arrow D) to the second arcuate turn  70  of the pressure loss reducing structure  40 , which has an arcuate end wall  72 . The flow of cooling gas  36  flows from the return channel  38  into the second arcuate turn  70  through an inlet  12 . The flow of cooling gas  36  is redirected (arrow E) toward and into (arrow F) the central plenum  44  by the arcuate end wall  72  and the peaked junction  80  through an outlet O 2 , forming another portion of the flow of cooling gas  42 . The return channel  38  and the central plenum  44  are separated by a rib  76 . The flow of cooling gas  36  flows around an end section  78  of the rib  76 . 
         [0028]    In embodiments, the arcuate end walls  62 ,  72  and the peaked junction  80  formed by the distal ends of the first and second arcuate turns  60 ,  70  prevent impingement of the flows of cooling gas  26 ,  36  and direct the flows of cooling gas  26 ,  36  upward toward and into the central plenum  44 . In the central plenum  44 , the flows of cooling gas  26 ,  36  combine to produce the flow of cooling gas  42 . 
         [0029]    The arcuate end walls  62 ,  72  of the first and second arcuate turns  60 ,  70  may be substantially semicircular. Thus, the flows of cooling gas  26 ,  36  may be rotated up to about 180° as the flows of cooling gas  26 ,  36  pass around the end sections  68 ,  78  of the ribs  66 ,  76 . Other suitable configurations of the first and second end walls  62 ,  72  of the arcuate turns  60 ,  70  may also be used in various implementations of the pressure loss reducing structure  40 . 
         [0030]      FIG. 4  is a partial cross-sectional view of the blade of  FIG. 1  depicting the pressure loss reducing structure  40 . As shown, the flow of cooling gas  26  flows through the return channel  28  in a first direction (into the page in  FIG. 4 ) to a first arcuate turn  60  of the pressure loss reducing structure  40 . At the first arcuate turn  60 , the flow of cooling gas  26  is redirected in a second direction (out of the page in  FIG. 4 ) by the arcuate end wall  62  and peaked junction  80  and flows into the central plenum  44 , forming a portion of the flow of cooling gas  42 . The return channel  28  and the central plenum  44  are separated by the rib  66 . 
         [0031]    The flow of cooling gas  36  flows through the return channel  38  in a first direction (into the page in  FIG. 4 ) to the second arcuate turn  70  of the pressure loss reducing structure  40 . At the second turn  70 , the flow of cooling gas  36  is redirected in a second direction (out of the page in  FIG. 4 ) by the arcuate end wall  72  and peaked junction  80  and flows into the central plenum  44 , forming another portion of the flow of cooling gas  42 . The return channel  38  and the central plenum  44  are separated by the rib  76 . 
         [0032]    Another embodiment of a pressure loss reducing structure  50  is depicted in  FIG. 5 . Unlike the previously described pressure loss reducing structure  40 , the pressure loss reducing structure  50  includes a plurality of sets  90 A,  90 B of turning vanes  92 ,  94 , which are configured to redirect the flows of cooling gas  26 ,  36  into the central plenum  44  with reduced impingement and associated pressure loss. 
         [0033]    As shown, the flow of cooling gas  26  flows through the return channel  28  in a first direction (arrow G) to a first arcuate turn  160  of the pressure loss reducing structure  50 . In this embodiment, the arcuate configuration of the first arcuate turn  160  is provided by the set  90 A of turning vanes  92 ,  94 , rather than shape of the turn itself ( FIG. 3 ) as in the above-described embodiment. At the first arcuate turn  160 , the flow of cooling gas  26  is redirected (arrows H, I) by the set  90 A of turning vanes  92 ,  94  and an end wall  162 . The redirected flow of cooling gas  26  flows toward and into (arrow J) the central plenum  44 , forming a portion of the flow of cooling gas  42 . The return channel  28  and the central plenum  44  are separated by a rib  166 . As shown in  FIG. 5 , the flow of cooling gas  26  flows around an end section  168  of the rib  166 . 
         [0034]    Also depicted in  FIG. 5  is a second arcuate turn  170  of the pressure loss reducing structure  50 . The flow of cooling gas  36  flows through the return channel  38  in a first direction (arrow K) to the second arcuate turn  170  of the pressure loss reducing structure  50 . At the second arcuate turn  170 , the flow of cooling gas  36  is redirected (arrows L, M) by the set  90 B of turning vanes  92 ,  94  and an end wall  172 . The end wall  172  may be substantially coplanar with the end wall  162 . Similar to the first arcuate turn  160 , the arcuate configuration of the second arcuate turn  170  is provided by the set  90 B of turning vanes  92 ,  94  rather than shape of the turn itself ( FIG. 3 ) as in the above-described embodiment. The redirected flow of cooling gas  36  subsequently flows toward and into (arrow N) into the central plenum  44 , forming another portion of the flow of cooling gas  42 . The return channel  38  and the central plenum  44  are separated by a rib  176 . The flow of cooling gas  36  flows around an end section  178  of the rib  176 . 
         [0035]    In embodiments, the turning vanes  92 ,  94  have an arcuate configuration. Although described as including two turning vanes  92 ,  94 , each set of turning vanes  90 A,  90 B may include any number of suitably arranged turning vanes. For instance, as shown in  FIG. 6 , a single turning vane  102  may be provided in the first and second arcuate turns  160 ,  170 . More than two turning vanes may also be used. 
         [0036]    As shown in  FIG. 5 , in each of the sets  90 A,  90 B of turning vanes  92 ,  94 , a concave face  98  of the turning vane  92  faces a concave face  100  of the turning vane  94 , thereby forming arcuate paths (H, I),(L, M) in the first and second arcuate turns  160 ,  170 . The turning vanes  92 ,  94  in each set  90 A,  90 B are configured such that the flow direction of the flows of cooling gas  26 ,  36  may be rotated up to about 180° as the flows of cooling gas  26 ,  36  pass around the end sections  168 ,  178  of the ribs  166 ,  176 . The turning vanes may be positioned away from the end walls  168 ,  178  of the first and second arcuate turns  160 ,  170 . To this extent, the flow of cooling gas  26  may flow around both sides of the turning vanes  92 ,  94  of set  90 A (as represented by arrows H, I), while the flow of cooling gas  36  may flow around both sides of the turning vanes  92 ,  94  of set  90 B (as represented by arrows L, M). 
         [0037]      FIG. 7  is a partial cross-sectional view of the blade of  FIG. 1  depicting the pressure loss reducing structure  50 . As shown, the flow of cooling gas  26  flows through the return channel  28  in a first direction (into the page in  FIG. 7 ) to the first arcuate turn  160  of the pressure loss reducing structure  40 . At the first arcuate turn  160 , the flow of cooling gas  26  is redirected in a second direction into the central plenum  44  (out of the page in  FIG. 7 ) by the turning vanes  92 ,  94  of set  90 A and the end wall  162 , forming a portion of the flow of cooling gas  42 . The return channel  28  and the central plenum  44  are separated by the rib  166 . 
         [0038]    The flow of cooling gas  36  flows through the return channel  38  in a first direction (into the page in  FIG. 7 ) to the second arcuate turn  170  of the pressure loss reducing structure  40 . At the second arcuate turn  170 , the flow of cooling gas  36  is redirected in a second direction into the central plenum  44  (out of the page in  FIG. 7 ) by the turning vanes  92 ,  94  of set  90 B and the end wall  172 , forming a portion of the flow of cooling gas  42 . The return channel  38  and the central plenum  44  are separated by the rib  176 . 
         [0039]    In various embodiments, components described as being “coupled” to one another can be joined along one or more interfaces. In some embodiments, these interfaces can include junctions between distinct components, and in other cases, these interfaces can include a solidly and/or integrally formed interconnection. That is, in some cases, components that are “coupled” to one another can be simultaneously formed to define a single continuous member. However, in other embodiments, these coupled components can be formed as separate members and be subsequently joined through known processes (e.g., fastening, ultrasonic welding, bonding). 
         [0040]    When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0041]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
         [0042]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.