Patent Publication Number: US-11377956-B2

Title: Cover plate with flow inducer and method for cooling turbine blades

Description:
FIELD OF THE INVENTION 
     This invention relates generally to a flow inducer assembly and a method for cooling turbine blades of a gas turbine engine, in particular, the last stage turbine blades of the gas turbine engine, using ambient air. 
     DESCRIPTION OF RELATED ART 
     An industrial gas turbine engine typically includes a compressor for compressing air, a combustor for mixing the compressed air with fuel and igniting the mixture, a turbine section for producing mechanical power, and a generator for converting the mechanical power to an electrical power. The turbine section includes a plurality of turbine blades that are attached on a rotor disk. The turbine blades are arranged in rows axially spaced apart along the rotor disk and circumferentially attached to a periphery of the rotor disk. The turbine blades are driven by the ignited hot gas from the combustor and are cooled using a coolant, such as a cooling fluid, through cooling passages in the turbine blades. 
     Typically, cooling fluid may be supplied by bleeding compressor air. However, bleeding air from the compressor may reduce turbine engine efficiency. Due to high operation pressures of the first, second and third stage turbine blades, bleeding compressor air may be required for cooling the first, second and third stage turbine blades. The last stage turbine blades operate under the lowest pressure, ambient air may be used for cooling the last stage turbine blades. In order to sufficiently cool the last stage turbine blades to achieve required boundary conditions, an efficient flow inducer system is needed to bring sufficient amount of the ambient air into cooling passages of the last stage turbine blade. There is a need to provide an easy and simple system to capture sufficient amount of ambient air into the cooling passages of the last stage turbine blade for sufficiently cooling the last stage turbine blades. 
     SUMMARY OF THE INVENTION 
     Briefly described, aspects of the present invention relate to a gas turbine engine, a seal plate configured to be attached to a rotor disk of a gas turbine engine, and a method for cooling turbine blades of a gas turbine engine. 
     According to an aspect, a gas turbine engine is presented. The gas turbine engine comprises a rotor disk comprising a plurality of circumferentially distributed disk grooves. Each disk groove comprises a blade mounting section and a disk cavity. The gas turbine engine comprises a plurality of turbine blades. Each turbine blade comprises a blade root that is inserted into the blade mounting section of the disk groove. The gas turbine engine comprises a plurality of seal plates attached to an aft side circumference of the rotor disk. Each seal plate comprises an upper seal plate wall and a lower seal plate wall. The upper seal plate wall is configured to cover the blade root. The gas turbine engine comprises a plurality of flow inducer assemblies. Each flow inducer assembly is integrated to each seal plate at a side facing away from the rotor disk. The flow inducer assembly is configured to function as a paddle due to rotation of the rotor disk and the seal plate therewith during operation of the gas turbine engine to drive a cooling fluid into the disk cavity and enter inside of the turbine blade from the blade root for cooling the turbine blade. 
     According to an aspect, a seal plate configured to be attached to a rotor disk of a gas turbine engine is presented. The gas turbine engine comprises a rotor disk comprising a plurality of circumferentially distributed disk grooves. Each disk groove comprises a blade mounting section and a disk cavity. Each turbine blade comprises a blade root that is inserted into the blade mounting section of the disk groove. The seal plate is attached to an aft side of the rotor disk. The seal plate comprises an upper seal plate wall configured to cover the blade root. The seal plate comprises a lower seal plate wall. The seal plate comprises a flow inducer assembly integrated to the seal plate at a side facing away from the rotor disk. The flow inducer assembly is configured to function as a paddle due to rotation of the rotor disk and the seal plate therewith during operation of the gas turbine engine to drive a cooling fluid into the disk cavity and enter inside of the turbine blade from the blade root for cooling the turbine blade 
     According to an aspect, a method cooling turbine blades of a gas turbine engine is presented. The gas turbine engine comprises a rotor disk comprising a plurality of circumferentially distributed disk grooves. Each disk groove comprises a blade mounting section and a disk cavity. Each turbine blade comprises a blade root that is inserted into the blade mounting section of the disk groove. The method comprises attaching a plurality of seal plates to aft side circumference of the rotor disk. Each seal plate comprises an upper seal plate wall and a lower seal plate wall. The upper seal plate wall is configured to cover the blade root. The method comprises attaching a plurality of flow inducer assemblies to the seal plates. Each flow inducer assembly is integrated to each seal plate at a side facing away from the rotor disk. The flow inducer assembly is configured to function as a paddle due to rotation of the rotor disk and the seal plate therewith during operation of the gas turbine engine to drive a cooling fluid into the disk cavity and enter inside of the turbine blade from blade root for cooling the turbine blade. 
     Various aspects and embodiments of the application as described above and hereinafter may not only be used in the combinations explicitly described, but also in other combinations. Modifications will occur to the skilled person upon reading and understanding of the description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the application are explained in further detail with respect to the accompanying drawings. In the drawings: 
         FIG. 1  illustrates a schematic perspective view of a portion of a gas turbine engine showing the last stage, in which embodiments of the present invention may be incorporated; 
         FIGS. 2 to 7  illustrate schematic perspective views of flow inducer assemblies according to various embodiments of the present invention; 
         FIG. 8  illustrates a schematic perspective view of a portion of a gas turbine engine showing the last stage, in which an embodiment of the present invention shown in  FIG. 7  is incorporated; and 
         FIG. 9  illustrates a schematic perspective view of a locking plate which is shown in  FIG. 8 . 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A detailed description related to aspects of the present invention is described hereafter with respect to the accompanying figures. 
       FIG. 1  illustrates a schematic perspective view of a portion of a gas turbine engine  100  showing the last stage looking in an aft side with respect to an axial flow direction. The gas turbine engine  100  includes a flow inducer assembly  300  according to embodiments of the present invention. As illustrated in  FIG. 1 , the gas turbine engine  100  includes a last stage rotor disk  120  and a plurality of last stage turbine blades  140  that are attached along an outer circumference of the rotor disk  120 . A plurality of seal plates  200  are attached to the aft side circumference of the last stage rotor disk  120 . The seal plate  200  may prevent hot gas coming into the aft side of the rotor disk  120 . The seal plates  200  are secured to the rotor disk  120 . The rotor disk  120  may rotate in a direction as indicated by the arrow R during operation of the gas turbine engine  100 , which rotates the turbine blades  140  and the seal plates  200  therewith in the same direction R. For clarity purpose, one turbine blade  140  and one seal plate  200  are removed from the rotor disk  120 . 
     With reference to  FIG. 1 , the rotor disk  120  includes a plurality of disk grooves  122 . Each disk groove  122  includes a blade mounting section  124  and a disk cavity  126 . Each turbine blade  140  includes a platform  142  and a blade root  144  that extends radially downward from the platform  142 . Each turbine blade  140  is attached to the rotor disk  120  by inserting the blade root  144  into the blade mounting section  124  of the rotor disk groove  122 . The disk cavity  126  is formed between the blade root  144  and bottom of the disk groove  122 . Each seal plate  200  includes an upper seal plate wall  220  and a lower seal plate wall  240 . A seal arm  230  may extend axially outward between the upper seal plate wall  220  and the lower seal plate wall  240 . The upper seal plate wall  220  covers the blade root  144 . A flow inducer assembly  300  is attached to the lower seal plate wall  240 . The flow inducer assembly  300  aligns with the disk cavity  126  of the disk groove  122 . 
     During engine operation, rotation of the last stage turbine blades  140  creates a pumping force to drive cooling fluid into the disk cavity  126  of the disk groove  120  as indicated by the cooling flow arrow  130  due to a centrifugal force. The cooling fluid enters inside of the turbine blade  140  from the blade root  144  for cooling the turbine blade  140  and exits through openings in the turbine blade  140  to a gas path of the gas turbine engine  100 . The cooling fluid may be ambient air. According to embodiments of the present invention, the flow inducer assembly  300  arranged on the seal plate  200  provides further driving force to induce ambient air entering the disk cavity  126  for sufficiently cooling the last stage turbine blade  140 . The flow inducer assembly  300  and the seal plate  200  may be manufactured as an integrated single piece. 
       FIGS. 2 to 7  illustrate schematic perspective views of a seal plate  200  having an integrated flow inducer assembly  300  according to various embodiments of the present invention. 
       FIG. 2  illustrates a schematic perspective view of a seal plate  200  having an integrated flow inducer assembly  300  according to an embodiment of the present invention. As shown in  FIG. 2 , the seal plate  200  includes an upper seal plate wall  220  and a lower seal plate wall  240 . A seal arm  230  extends axially outward between the upper seal plate wall  220  and the lower seal plate wall  240 . The seal plate  200  may have a hook  202  displaced at a side of the upper seal plate wall  220  facing to the rotor disk  120 . The hook  202  may have a U-shape that attaches to the rotor disk  120 . The seal plate  200  may have a protrusion  204  protruded from a side of the lower seal plate wall  240  facing to the rotor disk  120 . The protrusion  204  may have a dovetail shape that attaches to the rotor disk  120 . The hook  202  and the protrusion  204  secure the seal plate  200  to the rotor disk  120 . The seal plate  200  has an aperture  242  axially penetrating through the lower seal plate wall  240 . The aperture  242  may be located at the lower seal plate wall  240  with a radial distance below the seal arm  230 . The aperture  242  may align with the disk cavity  126  of the disk groove  122  after assembly. The aperture  242  may generally have a similar shape with the disk cavity  126 . 
     According to an exemplary embodiment as illustrated in  FIG. 2 , a flow inducer assembly  300  is integrated to the seal plate  200  at a side facing away from the rotor disk  120  and extends outward in an axial direction. The flow inducer assembly  300  may include a curved plate  310  attached radially along the aperture  242  at a downstream side with respect to the rotation direction R of the rotor disk  120  as shown in  FIG. 1 . The curved plate  310  may be blended with the aperture  242  in a tangential direction of the aperture  242 . The curved plate  310  may have a similar curvature with the aperture  242 . During operation of the gas turbine engine  100 , rotation of the rotor disk  120  and the seal plate  200  therewith makes the curved plate  310  of the flow inducer assembly  300  function as a paddle that further induces cooling air  130 , such as ambient air from outside of the gas turbine engine  100 , in addition to cooling air  130  that is induced by a centrifugal force caused by rotation of the turbine blades  140 , into the aperture  242  and the disk cavity  126  and enters insides of the turbine blades  140  from the blade roots  144  for cooling the turbine blades  140 . The curved plate  310  may have a scoop shape. 
     Dimensions of the flow inducer assembly  300  may be designed to achieve cooling requirement for sufficiently cooling the turbine blades  140 . Dimensions of the flow inducer assembly may include a radial height of the curved plate  310 , an axial length of the curved plate  310 , etc. A radial height of the curved plate  310  may be less than, or equal to, or greater than a radial height of the aperture  242 . For illustration purpose,  FIG. 2  and  FIG. 3  show the curved plates  310  having different radial heights. According to an exemplary embodiment as illustrated in  FIG. 2 , a radial height of the curved plate  310  is equal to a radial height of the aperture  242 . As illustrated in  FIG. 2 , the curved plate  310  is attached along the aperture  242  at the downstream side starting from the lowest point of the aperture  242  and ending at the highest point of the aperture  242 . 
     According to another exemplary embodiment as illustrated in  FIG. 3 , a radial height of the curved plate  310  is greater than a radial height of the aperture  242 . As illustrated in  FIG. 3 , the curved plate  310  is attached along the aperture  242  at the downstream side starting from the lowest point of the aperture  242  and ending at the seal arm  230 . Such embodiment may also improve mechanical properties of the flow inducer assembly  300 , such as increasing mechanical strength, reducing vibration, etc. It is understood that the curved plate  310  may be attached along the aperture  242  at the downstream starting at a radial point that is below the lowest point of the aperture  242 , or above the lowest point of the aperture  242 . It is also understood that the curved plate  310  may be attached along the aperture  242  at the downstream side ending at a radial point that is below the highest point of the aperture  242 , or between the highest point of the aperture  242  and the seal arm  230 . 
     An axial length of the curved plate  310  may change along a radial direction. According to exemplary embodiments as illustrated in  FIG. 2  and  FIG. 3 , the axial length of the curved plate  310  may be shorter in the lower portion and longer in the upper portion. For example, the maximum axial length of the curved plate  310  from the lower seal plate wall  240  may be located at the upper portion of the curved plate  310  that is near a region of the top of the curved plate  310 . 
       FIG. 4  illustrates a schematic perspective view of a seal plate  200  having an integrated flow inducer assembly  300  according to an embodiment of the present invention. The flow inducer assembly  300  viewing in a different perspective view direction is also illustrated in  FIG. 4 . As shown in  FIG. 4 , the flow inducer assembly  300  may include a floor plate  320  that is attached to the lower seal plate wall  240  and extends axially outward from the lower seal plate wall  240  at a radial location of the lowest point of the aperture  242 . The floor plate  320  may be parallel to the seal arm  230  of the seal plate  200 . The flow inducer assembly  300  may include an inner side wall  330  and an outer side wall  340  radially extending upward from the floor plate  320 . The inner side wall  330  and the outer side wall  340  may be radially attached between the floor plate  320  and the seal arm  230 . The inner side wall  330  and the outer side wall  340  are spaced apart from each other and attached at two circumferential sides of the aperture  242  forming a partial annular shape. The inner side wall  330  may be attached to the aperture  242  at the upstream side. The outer side wall  340  may be attached to the aperture  242  at the downstream side. The inner side wall  330  and the outer side wall  340  may be two curved plates. The arc length of the outer side wall  340  is longer than the arc length of the inner side wall  330  forming an inlet  350  facing to the rotation direction R of the rotor disk  120 . During operation of the gas turbine engine  100 , rotation of the rotor disk  120  and the seal plate  200  therewith makes the flow inducer assembly  300  function as a paddle that further induces cooling air  130 , such as ambient air from outside of the gas turbine engine  100 , in addition to cooling air  130  that is induced by a centrifugal force caused by rotation of the turbine blades  140 , into the flow inducer assembly  300  through the inlet  350  and flows into the aperture  242  and the disk cavity  126  and enters insides of the turbine blades  140  from the blade roots  144  for cooling the turbine blades  140 . 
       FIG. 5  illustrates a schematic perspective view of a seal plate  200  having an integrated flow inducer assembly  300  according to an embodiment of the present invention. The flow inducer assembly  300  viewing in a different perspective view direction is also illustrated in  FIG. 5 . As shown in  FIG. 5 , the floor plate  320  is laterally extended out the outer side wall  340 . A vertical plate  342  is attached to the outer side wall  340  at the extended area of the floor plate  320  and radially extends upward from the floor plate  320 . The vertical plate  342  may be attached between the floor plate  320  and the seal arm  230 . The outer side wall  340  and the vertical plate  342  may be formed as a Y-shape. The configuration of the flow inducer assembly  300  as shown in  FIG. 5  may improve mechanical properties of the flow inducer assembly  300 , such as increasing mechanical strength, reducing vibration, etc. 
       FIG. 6  illustrates a schematic perspective view of a seal plate  200  having an integrated flow inducer assembly  300  according to an embodiment of the present invention. The flow inducer assembly  300  viewing in a different perspective view direction is also illustrated in  FIG. 6 , As shown in  FIG. 6 , the floor plate  320  is laterally extended out the outer side wall  340 . The floor plate  320  is also laterally extended out the inner side wall  330  and attached to the lower seal plate wall  240 . The configuration of the flow inducer assembly  300  as shown in  FIG. 6  may improve mechanical properties of the flow inducer assembly  300 , such as increasing mechanical strength, reducing vibration, etc. 
     Dimensions of the flow inducer assembly  300  may be designed to achieve cooling requirement for sufficiently cooling the turbine blades  140 . Dimensions of the flow inducer assembly  300  may include radial heights of the inner side wall  330  and the outer side wall  340 , circumferential distance between the inner side wall  330  and the outer side wall  340 , orientation of the inlet  350  with respect to rotation direction R of the rotor disk  120 , etc. The radial heights of the inner side wall  330  and the outer side wall  340  may be defined by a radial distance between the floor plate  320  and the seal arm  230 . The floor plate  320  may be attached to the lower seal plate wall  240  at a radial location of the lowest radial point of the aperture  242 , as illustrated in  FIGS. 4-6 . It is understood that the floor plate  320  may be attached to the lower seal plate wall  240  at a radial location below the lowest radial point of the aperture  242 . The inner side wall  330  and the outer side wall  340  may be located at upstream and downstream edges of the aperture  242 , or further away from the upstream and downstream edges of the aperture  242 . Orientation of the inlet  350  may be perpendicularly to the rotation direction R which may drive more cooling air into the flow inducer assembly  300  in comparison with the orientation of the inlet  350  with an angle that is less than or greater than 90° with respect to the rotation direction R. 
       FIG. 7  illustrates a schematic perspective view of a seal plate  200  having an integrated flow inducer assembly  300  according to an embodiment of the present invention. As shown in  FIG. 7 , a root  244  is attached to the lower seal plate wall  240  and extends radially downward. The root  244  may have a dovetail shape. A flow inducer assembly  300  is integrated to the root  244  at a side facing away from the rotor disk  120  and extends outward in an axial direction. The flow inducer assembly  300  may include a curved plate  310 . The curved plate  310  may have a scoop shape. The curved plate  310  may have a similar configuration as illustrated in  FIGS. 2-3 , which is not described in detail herewith. 
       FIG. 8  illustrates a schematic perspective view of a portion of a gas turbine engine  100  showing the last stage looking in an aft side with respect to an axial flow direction, in which an embodiment of the present invention shown in  FIG. 7  is incorporated. For clarity purpose, one turbine blade  140  and one seal plate  200  are removed from the rotor disk  120 . As shown in  FIG. 8 , the seal plate  200  is attached to the rotor disk  120 . The root  244  is displaced into the disk groove  122 . The curved plate  310  is radially along the disk cavity  126  at a downstream side with respect to the rotation direction R of the rotor disk  120  after assembly. During operation of the gas turbine engine  100 , rotation of the rotor disk  120  and the seal plate  200  therewith makes the curved plate  310  of the flow inducer assembly  300  function as a paddle that further induces cooling air  130 , such as ambient air, in addition to cooling air  130  that is induced by a centrifugal force caused by rotation of the turbine blades  140 , into the disk cavity  126  and enters insides of the turbine blades  140  from the blade roots  144  for cooling the turbine blades  140 . A locking plate  246  may be inserted into a disk slot  128  for securing the seal plate  200  to the rotor disk  120 .  FIG. 9  illustrates a schematic perspective view of a locking plate  246 . 
     According to an aspect, the proposed flow inducer assembly  300  may enable using ambient air as cooling fluid  130  for sufficiently cooling the last stage of turbine blades  140  of a gas turbine engine  100 . During operation of the gas turbine engine  100 , rotation of the rotor disk  120  and the seal plate  200  therewith makes the flow inducer assembly  300  function as a paddle that drives sufficient amount of ambient air from outside of the gas turbine engine  100  as the cooling air  130  into disk cavities  126  of rotor disk  120  and enters insides of the turbine blades  140  from the blade roots  144  for cooling the turbine blades  140 . The proposed flow inducer assembly  300  eliminates bleeding compressor air for cooling the last stage of turbine blades  140 , which increases turbine engine efficiency. 
     According to an aspect, the proposed flow inducer assembly  300  may be manufactured as an integrated piece of the seal plate  200 . The seal plate  200  and the integrated flow inducer assembly  300  provide a lightweight design for preventing hot gas coming into the rotor disk  120  and simultaneously driving enough ambient air for sufficiently cooling the last stage of turbine blades  140  to achieve required boundary condition. The seal plate  200  and the integrated flow inducer assembly  300  provide sufficient cooling of the last stage of the turbine blades  140  with minimal cost. 
     Although various embodiments that incorporate the teachings of the present invention have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings. The invention is not limited in its application to the exemplary embodiment details of construction and the arrangement of components set forth in the description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
     REFERENCE LIST 
     
         
           100 : Gas Turbine Engine 
           120 : Rotor Disk 
           122 : Disk Groove 
           124 : Blade Mounting Section 
           126 : Disk Cavity 
           128 : Disk Slot 
           130 : Cooling Flow 
           140 : Turbine Blade 
           142 : Blade Platform 
           144 : Blade Root 
           200 : Seal Plate 
           202 : Seal Plate Hook 
           204 : Seal Plate Protrusion 
           220 : Upper Seal Plate Wall 
           230 : Seal Arm 
           240 : Lower Seal Plate Wall 
           242 : Aperture on Lower Seal Plate Wall 
           244 : Seal Plate Root 
           246 : Locking Plate 
           300 : Flow Inducer Assembly 
           310 : Curved Plate having Scoop Shape 
           320 : Floor Plate 
           330 : Inner Side Wall 
           340 : Outer Side Wall 
           342 : Vertical Wall 
           350 : Cooling Fluid Inlet