Abstract:
Disclosed is a seal for turbomachinery including a seal face locatable between a first turbomachinery component and a second turbomachinery component. At least one fluid channel extends through the seal. The at least one fluid channel is capable of injecting fluid flow between the first turbomachinery component and the second turbomachinery component at the seal face thereby disrupting a leakage flow between the first turbomachinery component and the second turbomachinery component. Further disclosed is a turbomachine utilizing the seal.

Description:
BACKGROUND 
     The subject invention relates to turbomachinery. More particularly the subject invention relates to sealing between turbomachinery components. 
     In a typical turbomachine, seals are utilized at various locations to prevent fluid flow from leaking around a desired flowpath. For example, seals are provided between rotating bucket tips and a stationary casing to direct flow past the buckets rather than between the bucket tips and the casing. Seals may also be utilized between a rotor and a stationary component in the form of one or more packing rings. Typical seal configurations include labyrinth seals, brush seals, abradable seals, patterned abradable seals and compliant plate seals. A labyrinth seal, for example, in the turbomachine typically includes one or more teeth extending from a first component toward a second component to create a tortuous path for fluid flow between the components. During operation of the turbomachinery, however, the teeth may rub on the second component and become damaged thereby increasing a gap between the teeth and the second component and subsequently allowing for increased leakage which negatively impacts efficiency of the turbomachine. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one aspect of the invention, a seal for turbomachinery includes a seal face locatable between a first turbomachinery component and a second turbomachinery component. At least one fluid channel extends through the seal. The at least one fluid channel is capable of injecting fluid flow between the first turbomachinery component and the second turbomachinery component at the seal face thereby disrupting a leakage flow between the first turbomachinery component and the second turbomachinery component. 
     According to another aspect of the invention, a turbomachine includes a first turbomachine component, a second turbomachine component, and at least one seal capable of reducing leakage flow between the first turbomachinery component and second turbomachinery component. The at least one seal includes a seal face disposed between the first turbomachinery component and the second turbomachinery component and at least one fluid channel extending through the seal. The at least one fluid channel is capable of injecting fluid flow between the first turbomachinery component and the second turbomachinery component at the seal face thereby disrupting a leakage flow between the first turbomachinery component and the second turbomachinery component. 
     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 
       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 objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a cross-sectional view of an embodiment of a seal for turbomachinery including radial seal teeth; 
         FIG. 2  is a cross-sectional view of an embodiment of a seal for turbomachinery including angled seal teeth; 
         FIG. 3  is a cross-sectional view of another embodiment of a seal for turbomachinery including angled seal teeth; 
         FIG. 4  is a cross-sectional view of yet another embodiment of a seal for turbomachinery including angled seal teeth; 
         FIG. 5  is a cross-sectional view of still another embodiment of a seal for turbomachinery including angled seal teeth; 
         FIG. 6  is a cross-sectional view of an embodiment of a seal for turbomachinery including an abradable seal; 
         FIG. 7  is a partial cross-sectional view of a turbomachine schematically illustrating locations of the seal of  FIG. 1 ; and 
         FIG. 8  is a partial cross-sectional view of a turbomachine schematically illustrating an additional location of the seal of  FIG. 1 . 
     
    
    
     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 
     Shown in  FIG. 1  is an embodiment of a packing ring  10  disposed in a casing  12  of a turbomachine  14  with fluid flow through the turbomachine  14  occurring in a generally axial direction  16 . The packing ring  10  extends circumferentially around a rotor  18 . The packing ring  10  includes a seal face  20  facing the rotor  18 . The packing ring  10  includes at least one fluidic diode  22 , which includes at least one inlet  24  in flow communication with at least one return channel  26 , and at least one outlet  28  in flow communication with the at least one return channel  26 . While the embodiment of the packing ring  10  in  FIG. 1  has one inlet  24 , one return channel  26 , and one outlet  28 , other configurations having, for example, two inlets  24 , two return channels  26 , and/or two outlets  28 , are contemplated within the scope of the present disclosure. Flow through the turbomachine  14 , shown by arrows  16 , enters a gap  32  between the seal face  20  and the rotor  18 , and a first portion  34  of the flow  16  enters the fluidic diode  22  at the at least one inlet  24 . The first portion  34  passes through the at least one return channel  26  and is injected into the flow  16  at an injection angle  36  with a strong velocity component directed against the flow  16  through the at least one outlet  28 , located at the seal face  20 . In the embodiment of  FIG. 1 , the at least one inlet  24  is located upstream of the at least one outlet  28 , but it is to be appreciated that other locations of the at least one inlet  24  and the at least one outlet  28  are contemplated within the scope of the present disclosure. Injection of the first portion  34  into the flow  16  at an angle  36  conflicting with the flow  16  decreases an effective passage area and results in a disruption of the flow  16 . The disruption of flow  16  increases a fluidic resistance of the flow  16  between the seal face  20  and the rotor  18 . This increase in fluidic resistance induces a reduction of an amount of leakage between the seal face  20  and the rotor  18 . 
     In the embodiment shown in  FIG. 1 , the at least one inlet  24  is located at the seal face  20 , but it is to be appreciated that the at least one inlet  24  may be disposed at other portions of the packing ring  10 . For example, as shown in  FIG. 2 , in some embodiments the at least one inlet  24  is disposed at an upstream face  38 . High pressure fluid  40  enters the at least one inlet  24 , and flows through at least one return channel  26  and exits the at least one outlet  28  at the injection angle  36  with a strong velocity component directed against the flow  16 . 
     In another embodiment, as shown in  FIG. 3 , the at least one inlet  24  is disposed at a radially outboard face  42  of the packing ring  10 . The high pressure fluid  40  enters the at least one inlet  24  and flows through the at least one return channel  26 . The high pressure fluid  40  exits the at least one outlet  28  at the injection angle  36  with a strong velocity component directed against the flow  16 . In this embodiment, the at least one return channel  26  may be substantially straight and additionally may be disposed at an angle substantially equal to the injection angle  36 . As shown in  FIG. 3 , a channel width  44  of the return channel  26  may decrease from the at least one inlet  24  to the at least one outlet  28 . The reduction in channel width  46  increases a velocity of the high pressure fluid  40  through the return channel  26  to increase effectiveness of the packing ring  10 . 
     Referring to  FIG. 4 , some embodiments of the packing ring  10  include a plurality of seal teeth  48  extending from the seal face  20  toward the rotor  18 . The plurality of seal teeth  48  may extend in a substantially radially inboard direction, or at a tooth angle  50  relative to the seal face  20 . In some embodiments, the at least one inlet  24  is disposed at the seal face  20  and located axially between adjacent seal teeth  48 . Likewise, the at least one outlet  28  may be disposed between adjacent seal teeth  48 . Alternatively, as shown in  FIG. 5 , at least one inlet  24  and/or at least one outlet  28  may be disposed at a tooth tip  52  of a seal tooth  48 . In some embodiments, the injection angle  36  is substantially equal to the tooth angle  50  to improve effectiveness of the packing ring  10 . 
     In some embodiments, as shown in  FIG. 6 , the packing ring  10  may include an abradable seal  54  disposed at the seal face  20 . The rotor  18  in some embodiments includes a pattern having a plurality of seal teeth  56 . One or more fluidic diodes  22  are disposed such that the at least one inlet  24  and at least one outlet  28  may extend through the abradable seal  54 . 
     Referring again to  FIG. 1 , the fluidic diode  22  extends circumferentially with the packing ring  10  about the rotor  18 . In some embodiments, a plurality of fluidic diodes  22  are arranged circumferentially about the rotor  18  separated by a plurality of supports (not shown). The fluidic diode  22  may be manufactured by one of several means. The fluidic diode  22  may be formed by casting as a unitary, single-piece circumferential ring, with one or more struts  58  extending from an inner diode section  60  to an outer diode section  62 . Alternatively, the inner diode section  60  and outer diode section  62  may be formed separately by casting or other means, and assembled with one or more struts  58  into a fluidic diode  22  via, for example, welding or the use of mechanical fasteners. 
     While to this point, the packing ring  10  has been described as located at the packing casing  12  and sealing to the rotor  18 , other locations of the packing ring  10  including at least one fluidic diode  22  are contemplated within the scope of the present disclosure. For example, as shown in  FIG. 7 , the packing ring  10  including at least one fluidic diode  22  is disposed at a casing  64  to provide sealing between the casing  64  and at least one bucket tip  66 . Further, the packing ring  10  including at least one fluidic diode  22  may be located at a hub  68  to provide sealing to the rotor  18 . As a further example, illustrated in  FIG. 8 , the packing ring  10  including at least one fluidic diode  22  may be disposed at a stator  70  to provide sealing between the stator  70  and the rotor  18 . These seal locations are merely exemplary of uses of a seal including at least one fluidic diode  22  to enhance robustness of sealing between moving components and stationary components of a turbomachine  14 . It is to be appreciated, however that utilization of a seal including a fluidic diode  22  at other locations, for example, between stationary components of a turbomachine, is contemplated within the present scope. 
     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.