Systems and methods for cooling end walls in rotating machinery

Abstract

The present invention is titled "System and Method for Cooling Endwalls in Rotating Machinery". The present invention provides a core (300) for cooling a component (207) used in a rotating machine (100). The core (300) includes a passage (600) that includes a dividing wall (620) that separates a first inlet portion (606) from a second inlet portion (608) to define a split tube pass inlet (610) that is fluidly coupled to at least one first tube pass (612), at least one second tube pass (614), and at least one turn (616). At least one first tube pass (612) conveys a cooling fluid flow from the split tube pass inlet (610) in a first direction (630). At least one second tube pass (614) conveys a cooling fluid flow in a second direction (632) opposite the first direction (630). At least one turn (616) changes the flow direction of the cooling fluid from the first direction (630) to the second direction (632). At least one first tube pass (612), at least one second tube pass (614), and at least one turn (616) are arranged such that the passage (600) defines a serpentine passage (600).

Description

BACKGROUND OF THE DISCLOSURE

[0001] The present disclosure generally relates to cooling systems and, more particularly, to impingement cooling for rotating machine components.

[0002] In at least some known rotating machines, energy extracted from the airflow in a turbine is used to power a mechanical load. During operation of the rotating machine, various hot gas path components may be subjected to high temperature airflow. Over time, continued exposure to high temperatures may cause wear of the hot gas path components. For example, in some known turbines, air is pressurized in a compressor and mixed with fuel in a combustor to produce high temperature gases. Generally, higher temperature gases improve the performance, efficiency, and power output of the rotating machine. To help reduce the effects of high temperatures, at least some known hot gas path components are cooled. However, higher temperature gases also increase the thermal stress and / or thermal degradation of the rotating machine components.

[0003] Some known hot gas path components are formed by end walls that include internal cooling systems, where a cooling fluid such as bleed air extracted from a compressor or steam is forced through a core defined within the end wall. At least some known cores are formed with an inlet opening that delivers the cooling fluid into the core and directs the cooling fluid to impinge on the inner surface of the core, thereby enhancing the cooling of the end wall. However, at least some known cores include a set of pin shafts that deliver the cooling fluid directly from the inlet opening to at least one outlet opening, rather than delivering the cooling fluid in a circuit through the end wall. Thus, the core is not as effective at cooling as a core that includes serpentine or tortuous channels. Additionally, at least some known cores have serpentine or tortuous channels that deliver the cooling fluid through the end wall from a single inlet. However, in known cores, it may be difficult to regulate the pressure drop within the channels. SUMMARY OF THE INVENTION

[0004] In one aspect, a core for cooling a component used in a rotating machine is provided. The core includes a channel that includes a first inlet portion, a second inlet portion, a dividing wall, at least one first pass, at least one second pass, and at least one turn. The dividing wall separates the first inlet portion from the second inlet portion such that the first inlet portion, the second inlet portion, and the dividing wall define a split-pass inlet. At least one first pass conveys a cooling fluid flow from the split-pass inlet in a first direction. At least one second pass conveys the cooling fluid flow in a second direction opposite the first direction. At least one turn changes the direction of flow of the cooling fluid from the first direction to the second direction. At least one first pass, at least one second pass, and at least one turn are arranged such that the channel defines a serpentine channel.

[0005] In another aspect, a gas turbine system is provided. The gas turbine system includes a turbine section having an inner end wall, an outer end wall, a plurality of vanes, and a core. The turbine section is fluidly coupled to a combustion system. The inner end wall circumscribes a longitudinal axis of the gas turbine system. The outer end wall circumscribes the longitudinal axis of the gas turbine system and the inner end wall. The plurality of vanes each extend between the outer end wall and the inner end wall. The core is positioned within at least one of the outer end wall and the inner end wall for cooling at least one of the outer end wall and the inner end wall. The core includes a passage that includes a first inlet portion, a second inlet portion, a dividing wall, at least one first pass, at least one second pass, and at least one turn. The dividing wall separates the first inlet portion from the second inlet portion such that the first inlet portion, the second inlet portion, and the dividing wall define a split-pass inlet. At least one first pass conveys a cooling fluid flow in a first direction from the split-pass inlet. At least one second pass conveys a cooling fluid flow in a second direction opposite the first direction. At least one turn changes a flow direction of the cooling fluid from the first direction to the second direction. At least one first pass, at least one second pass, and at least one turn are arranged such that the passage defines a serpentine passage.

[0006] In another aspect, a method of cooling a component of a rotating machine is provided. The method includes inserting a core into an inflatable chamber within the component. The core includes a passage that includes an inlet portion, at least one first pass, at least one second pass, and at least one turn. The inlet portion includes a first inlet portion, a second inlet portion, and a dividing wall. The dividing wall separates the first inlet portion from the second inlet portion such that the inlet portion is a split-pass inlet. The method further includes conveying a cooling fluid flow into the first inlet portion and the second inlet portion. The method further includes conveying the cooling fluid flow from the first inlet portion and the second inlet portion into at least one first pass. The cooling fluid flow from the first inlet portion combines with the cooling fluid flow from the second inlet portion, and at least one first pass conveys the cooling fluid flow in a first direction. The method further includes conveying the cooling fluid flow from at least one first pass into at least one turn. At least one turn changes a flow direction of the cooling fluid from the first direction to a second direction opposite the first direction. The method further includes conveying the cooling fluid flow from at least one turn into at least one second pass. At least one first pass, at least one second pass, and at least one turn are arranged such that the passage defines a serpentine passage. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects, and advantages of the present disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters represent like parts throughout the drawings, wherein:

[0008] Figure 1 is a schematic illustration of an exemplary rotating machine;

[0009] Figure 2 An enlarged schematic view of an exemplary turbine stage of a rotary machine as shown; Figure 1 for the rotary machine shown;

[0010] Figure 3 is a perspective view of an exemplary stationary vane, outer end wall, and inner end wall that can be used with the turbine shown; Figure 2 for the turbine shown;

[0011] Figure 4 is a perspective top view of the stationary vane, outer end wall, and inner end wall, and an exemplary core extending through the transparent outer end wall and inner end wall as shown; Figure 2 for the stationary vane, outer end wall, and inner end wall shown;

[0012] Figure 5 is a radial top-down sectional view of the outer end wall as shown; Figure 4 for the outer end wall shown;

[0013] Figure 6 is a radial top view of the exemplary core as shown; and Figures 3 to 5 for the exemplary core shown; and

[0014] Figure 7 is a flowchart of an exemplary method of cooling an end wall (such as the end wall shown); Figures 2 to 6 for the end wall shown.

[0015] Unless otherwise specified, the figures provided herein are intended to illustrate features of embodiments of the present disclosure. It is believed that these features are applicable to a variety of systems including one or more embodiments of the present disclosure. Accordingly, the figures are not intended to include all conventional features known to those of ordinary skill in the art that are required to practice the embodiments disclosed herein. DETAILED DESCRIPTION

[0016] In the following specification and claims, a number of terms will be referenced, which shall be defined to have the following meanings.

[0017] Unless the context clearly dictates otherwise, the singular forms "a," "an," and "the" include plural references.

[0018] Unless otherwise indicated, approximating language, such as "substantially", "essentially", and "about", as used herein, indicates that the term so modified can vary only by an approximation to the extent recognized by one of ordinary skill in the art, rather than an absolute or perfect degree. Thus, values modified by one or more of the terms, such as "about", "approximately", and "substantially", are not limited to the specified exact value. In at least some instances, the approximating language may correspond to the precision of the instrument used to measure the value. Throughout this specification and the claims, range limitations may be identified. Unless the context or language indicates otherwise, these ranges may be combined and / or interchanged and include all sub-ranges subsumed therein. Additionally, unless otherwise indicated, the terms "first", "second", etc. are used herein only as labels and are not intended to impose an order, position, or ranking requirement on the items to which these terms refer. Further, for example, a reference to a "second" item does not require or preclude the existence of, for example, a "first" or lower-numbered item or a "third" or higher-numbered item.

[0019] As used herein, the terms "axial" and "axially" refer to a direction and orientation that extends substantially parallel to the longitudinal axis of a rotating machine. Additionally, the terms "radial" and "radially" refer to a direction and orientation that extends substantially perpendicular to the longitudinal axis of a rotating machine. Further, as used herein, the terms "circumferential" and "circumferentially" refer to a direction and orientation that extends arcuately about the longitudinal axis of a rotating machine. Additionally, as used herein, the term "upstream" refers to the front or inlet end of a rotating machine, and the term "downstream" refers to the rear or outlet end of a rotating machine. When discussing fluid flow through a component, the direction from which the fluid flows is described as "upstream", and the direction on which the fluid flows is described as "downstream".

[0020] The system described herein relates to a serpentine core for cooling portions of a hot gas path in a rotating machine. Specifically, in an exemplary embodiment, the rotating component includes an outer end wall formed in a nozzle of a turbine section within the rotating machine. The outer end wall includes a core for cooling the outer end wall. The core includes a serpentine channel that includes an inlet portion, a first pass, a second pass, and turns. The inlet portion includes a dividing wall, a first inlet portion, and a second inlet portion. The dividing wall separates the first inlet portion from the second inlet portion such that a split-pass inlet is defined. The first pass, the second pass, and the turns include a plurality of outlets that convey cooling fluid from the core into the hot gas path to form a cooling film on the outer end wall. A plurality of core straps convey cooling fluid from an upstream portion of the core to a downstream portion of the core such that the downstream portion can be supplemented with cooler temperature cooling fluid.

[0021] In an exemplary embodiment, a cooling fluid is conveyed through a first pass, a second pass, and a turn to facilitate cooling of an outer end wall from within a core. The serpentine configuration of the first pass, the second pass, and the turn enables the cooling fluid to cool a larger area of the outer end wall, thereby enhancing the overall heat transfer between the cooling fluid and the outer end wall. Additionally, the serpentine configuration enables the cooling fluid to circulate at a relatively low pressure that is substantially equal to the pressure of the combustion gas at the nozzle throat. Further, the width of each of the first pass, the second pass, and the turn is selected to facilitate modifying or tuning the pressure drop of the cooling fluid passing through the first pass, the second pass, and the turn and to enhance the overall heat transfer between the cooling fluid and the outer end wall. Additionally, an outlet conveys the cooling fluid into the hot gas path to facilitate forming a cooling film on the stator end wall. Additionally, the core tie straps replenish the cooling fluid for a downstream portion of the core, as well as provide an inspection access, stiffness during core formation, and leachability for ceramic core removal after the jacket process.

[0022] Figure 1 is a schematic illustration of an exemplary rotary machine 100 (i.e., a turbine), and more particularly a turbine engine. In an exemplary embodiment, the rotary machine 100 is a gas turbine engine. Alternatively, the rotary machine may be any other turbine engine and / or rotary machine, including but not limited to a steam turbine engine, a gas turbine fan aircraft engine, other aircraft engines, a wind turbine, a compressor, and a pump. In an exemplary embodiment, the gas turbine engine 100 includes an inlet section 102, a compressor section 104 coupled downstream of the inlet section 102, a burner section 106 coupled downstream of the compressor section 104, a turbine section 108 coupled downstream of the burner section 106, and an exhaust section 110 coupled downstream of the turbine section 108. The turbine section 108 is coupled to the compressor section 104 via a rotor shaft 112.

[0023] It should be noted that, as used herein, the term "coupled" is not limited to a direct mechanical, thermal, electrical, and / or fluid communication connection between components and may also include an indirect mechanical, thermal, electrical, and / or fluid communication connection between multiple components. In an exemplary embodiment, the burner section 106 includes a plurality of burners 114. The burner section 106 is coupled to the compressor section 104 such that each burner 114 is in fluid communication with the compressor section 104. The rotor shaft 112 is also coupled to a load 116, such as but not limited to a generator and / or a mechanical drive application. In an exemplary embodiment, each of the compressor section 104 and the turbine section 108 includes at least one rotor assembly 118 coupled to the rotor shaft 112.

[0024] During operation, an intake section 102 delivers air 120 toward a compressor section 104. The compressor section 104 compresses the inlet air 120 to a higher pressure and then discharges compressed air 122 toward a burner section 106. The compressed air 122 is delivered to the burner section 106 where it is mixed with fuel (not shown) and burned to produce hot combustion gases 124. The combustion gases 124 are delivered downstream toward a turbine section 108 and impinge on turbine blades (not shown), converting the thermal energy into mechanical rotational energy that is used to drive a rotor assembly 118 to rotate about a longitudinal axis 126. Generally, the burner section 106 and the turbine section 108 are referred to as the hot gas section of the turbine engine 100. If the rotating machine 100 is a gas turbine as part of a combined cycle power plant, the exhaust gas 128 is then discharged through an exhaust section 110 to the ambient atmosphere or a steam turbine (not shown).

[0025] Figure 2 An enlarged schematic view of an exemplary turbine stage 200 for a turbine engine 100 (shown in Figure 1 ). The stage 200 includes a plurality of radially extending stationary vanes 202 circumferentially spaced about a longitudinal axis 126, and a plurality of radially extending rotating vanes 204 downstream of the stationary vanes 202 and circumferentially spaced about the longitudinal axis 126. The radial direction is indicated by arrow 218. Each rotating vane 204 is coupled to a rotor shaft 112 (shown in Figure 1 ) via a disk 230 and extends radially outwardly toward a housing 208.

[0026] In an exemplary embodiment, each stationary vane 202 extends radially inwardly along a radial direction 218 from a first end 216 of an outer end wall 207 of the housing 208 coupled to the turbine section 108 to a second end 214 coupled to an inner end wall 209 (the outer end wall 208 and the inner end wall 209 are shown in Figure 3 ). Additionally, each stationary vane 202 extends axially downstream from a leading edge 222 to an opposite trailing edge 224. During operation, the outer end wall 207 and the inner end wall 209 define radial boundaries of a hot gas flow path 232 such that a flow of hot combustion gases 124 is delivered therethrough, thereby exposing the surfaces of the outer end wall 207 and the inner end wall 209 to high temperatures and potential thermal stresses and / or thermal degradation. To mitigate such thermal effects, an internal cavity or plenum 236 is defined within the outer end wall 207 and the inner end wall 209 to facilitate internal impingement cooling of the inner surfaces of the outer end wall 207 and the inner end wall 209.

[0027] The plenum chamber 236 is in fluid communication with the coolant supply passage 233 via a plenum chamber inlet 234 defined in the outer end wall 207 and the inner end wall 209. In an exemplary embodiment, the coolant supply passage 233 delivers a coolant fluid 240, such as a flow of pressurized discharge air from the compressor section 104 (shown in Figure 1 ), toward the plenum chamber inlet 234. Alternatively, the coolant fluid 240 can be any suitable fluid other than air. As used herein, the term "fluid" includes any flowing medium or material, including but not limited to air or steam. In an exemplary embodiment, stage 200 is the first stage of the turbine section 108, and the stationary vanes 202, the outer end wall 207, and the inner end wall 209 define a first stage turbine nozzle immediately downstream of the combustor section 106 (shown in Figure 1 ). In an alternative embodiment, stage 200 is any other stage of the turbine section 108. In an exemplary embodiment, the plenum chamber 236 extends axially rearward into the outer end wall 207 and the inner end wall 209.

[0028] Figure 3 is a perspective view of the stationary vanes 202, the outer end wall 207, and the inner end wall 209 and shows an exemplary core 300 extending through the transparent outer end wall 207 and inner end wall 209. Figure 4 is a perspective top view of the stationary vanes 202, the outer end wall 207, and the inner end wall 209. Figure 5 is a radial top cross-sectional view of an exemplary outer end wall 207. Figure 6 is a radial top view of an exemplary core 300. As Figures 3 to 5 shown, the core 300 is defined in the plenum chamber 236 of the outer end wall 207 and the inner end wall 209 for cooling the outer end wall 207 and the inner end wall 209. More specifically, the core 300 is disposed within the outer end wall 207 and the inner end wall 209 to facilitate cooling of the outer end wall 207 and the inner end wall 209 with the coolant fluid 240.

[0029] As Figures 3 to 5 shown, each of the stationary vanes 202 includes a suction sidewall 302 and a pressure sidewall 304 (shown in Figure 5 ). The adjacent stationary vanes 202, the outer end wall 207, and the inner end wall 209 define a throat 306 (shown in Figure 5 ) where the velocity of the combustion gas 124 is maximized. The outer end wall 207 includes an upstream portion 308 upstream of the stationary vanes 202 and a downstream portion 310 downstream of the stationary vanes 202. The outer end wall 207 also includes a trailing edge 312 adjacent to the rotating vane 204. In the illustrated embodiment, the core 300 is defined within the outer end wall 207 downstream of the suction sidewall 302. However, the core 300 can be positioned within the outer end wall 207 such that an upstream portion 314 of the core 300 (shown in Figure 5is upstream of the throat 306 and the downstream portion 316 of the core 300 is downstream of the throat 306. Further, the core 300 may be positioned within the outer end wall 207 such that the core 300 facilitates cooling of the outer end wall 207 and the trailing edge 312.

[0030] As Figure 6 shown, the core 300 includes at least one passage 600. In Figure 6 an exemplary embodiment, the passage 600 is a serpentine passage that conveys a cooling fluid 240 adjacent to the outer end wall 207 and the inner end wall 209 to facilitate cooling of the outer end wall 207 and the inner end wall 209. As Figure 3 and Figure 4 shown, a similar serpentine passage 600 may be used to convey the cooling fluid 240 adjacent to the inner end wall 209 to facilitate cooling of the inner end wall 209. As used herein, a "serpentine passage" is a conduit having at least one turn such that the passage winds or twists. That is, a serpentine passage does not have only a substantially straight path from an inlet to an outlet. Instead, the path from the inlet to the outlet forms at least one turn such that the serpentine passage does not have a direct line-of-sight path defined from the inlet to the outlet. In the exemplary embodiment, the serpentine passage 600 includes at least one inlet 602 and 604 that form a split header inlet region 610, a first inlet portion 606 and a second inlet portion 608; a first pass 612; a second pass 614; at least one turn 616 disposed between the first pass 612 and the second pass 614; and at least one outlet 618. The first pass 612, the second pass 614, and the turn 616 are oriented such that the passage 600 is a serpentine passage. In the illustrated embodiment, the serpentine passage 600 includes a plurality of inlets 602 and 604.

[0031] The inlets 602 and 604 receive the cooling fluid 240 from a coolant supply passage 233 ( Figure 2 ) and convey the cooling fluid 240 to the first inlet portion 606 and the second inlet portion 608. Specifically, at least one first inlet 602 conveys the cooling fluid 240 to the first inlet portion 606, and at least one second inlet 604 conveys the cooling fluid 240 to the second inlet portion 608. Figure 6A single inlet 602 and 604 extending into each inlet section 606 and 608 is shown. However, each inlet section 606 and 608 may include multiple inlets 602 and 604. Additionally, the serpentine channel 600 may include more than two inlet sections 606 and 608. For example, the first inlet 602 may include two to twenty first inlets 602 for delivering the cooling fluid 240 to the first inlet section 606, and the second inlet 604 may include two to twenty second inlets 604 for delivering the cooling fluid 240 to the second inlet section 608. More specifically, the first inlet 602 may include eight to ten first inlets 602 for delivering the cooling fluid 240 to the first inlet section 606, and the second inlet 604 may include eight to ten second inlets 604 for delivering the cooling fluid 240 to the second inlet section 608.

[0032] The partition wall 620 separates the first inlet section 606 from the second inlet section 608 to form a split tube pass inlet region 610. The partition wall 620 reduces the width 622 of the split tube pass inlet region 610 such that the velocity of the cooling fluid 240 passing through the split tube pass inlet region 610 increases. More specifically, since the width 622 of the split tube pass inlet region 610 increases downstream from the inlets 602 and 604, the velocity of the cooling fluid 240 passing through the split tube pass inlet region 610 without the partition wall 620 would decrease. The partition wall 620 reduces the width 622 such that the velocity of the cooling fluid 240 remains constant or increases as the cooling fluid 240 is delivered through the split tube pass inlet region 610.

[0033] Additionally, the first inlet section 606 defines a first width 624, and the second inlet section 608 defines a second width 626. The first width 624 may be the same as or different from the second width 626, and the dimensions of the first width 624 and the second width 626 may be selectively set such that a specific volume of the cooling fluid 240 can be delivered through the channel 600. More specifically, the dimensions of the first width 624 and the second width 626 may be set to be suitable for a specific volume flow rate of the cooling fluid 240 such that the heat transfer coefficient of the cooling fluid 240 is tuned to specific heat transfer requirements of the outer end wall 207 and / or the inner end wall 209.

[0034] The first inlet portion 606 and the second inlet portion 608 merge into the first tube pass 612, and each inlet portion delivers the cooling fluid 240 into the first tube pass 612. The first tube pass 612 extends through the outer end wall 207 substantially parallel to the trailing edge 312 and the second tube pass 614. The first tube pass 612 defines a third width 628, and the dimensions of the third width together with the first width 624 and the second width 626 can be selectively set such that a specific volumetric flow rate of the cooling fluid 240 can pass through it, so that the heat transfer coefficient of the cooling fluid 240 is tuned to the specific heat transfer requirements of the outer end wall 207 and / or the inner end wall 209. The first tube pass 612 receives the cooling fluid 240 from the first inlet portion 606 and the second inlet portion 608 and delivers the cooling fluid 240 to the bend 616.

[0035] The bend 616 receives the cooling fluid 240 from the first tube pass 612 and delivers the cooling fluid 240 to the second tube pass 614. The first tube pass 612, the second tube pass 614, and the bend 616 are oriented such that the first tube pass 612 delivers the cooling fluid 240 in a first direction 630, and the second tube pass 614 delivers the cooling fluid 240 in a second direction 632 opposite to the first direction 630. The bend 616 changes the flow direction of the cooling fluid 240 from the first direction 630 to the second direction 632. In an exemplary embodiment, the bend 616 is a 180° bend such that the first direction 630 and the second direction 632 are diametrically opposite. In an alternative embodiment, the first tube pass 612, the second tube pass 614, and the bend 616 can be oriented such that the first tube pass 612 and the second tube pass 614 have any orientation that enables the core 300 to operate as described herein. The bend 616 receives the cooling fluid 240 from the first tube pass 612, changes the flow direction of the cooling fluid 240, and delivers the cooling fluid 240 to the second tube pass 614.

[0036] The second tube pass 614 extends through the outer end wall 207 substantially parallel to the trailing edge 312 and the first tube pass 612. The second tube pass 614 defines a fourth width 634, and the dimensions of the fourth width together with the first width 624, the second width 626, and the third width 628 can be selectively set to achieve a specific volumetric flow rate of the cooling fluid 240, so that the heat transfer coefficient of the cooling fluid 240 is tuned to the specific heat transfer requirements of the outer end wall 207 and / or the inner end wall 209. The second tube pass 614 receives the cooling fluid 240 from the bend 616 and delivers the cooling fluid 240 to the outlet 618.

[0037] In an exemplary embodiment, the core 300 includes a single first pass 612, a single second pass 614, and a single turn 616. In an alternative embodiment, the core 300 may include any number of passes and / or turns that enable the core 300 to operate as described herein. For example, in an alternative embodiment, the core 300 may include three passes and two turns. In another alternative embodiment, the core 300 may include four passes and three turns.

[0038] The core 300 includes at least one outlet 618 downstream of the throat 306. Although the core 300 may include only a single outlet 618, in an exemplary embodiment, the core 300 includes a plurality of outlets 618 that convey cooling fluid from the core 300 into the hot gas flow path 232. For example, the core 300 may include at least one first outlet 636 that extends from the first pass 612 through the outer end wall 207 and into the hot gas flow path 232. In an exemplary embodiment, the core 300 includes a plurality of first outlets 636, each of which extends from the first pass 612 through the outer end wall 207 and into the hot gas flow path 232. The cooling fluid 240 discharged into the hot gas flow path 232 from the first outlet 636 may form a cooling film (not shown) on the outer end wall 207 that protects the outer end wall 207.

[0039] The core 300 may further include at least one second outlet 638 that extends from the second pass 614 through the outer end wall 207 and into the hot gas flow path 232. In an exemplary embodiment, the core 300 includes a plurality of second outlets 638, each of which extends from the second pass 614 through the outer end wall 207 and into the hot gas flow path 232. The cooling fluid 240 discharged into the hot gas flow path 232 from the second outlet 638 may form a cooling film (not shown) on the outer end wall 207 that is conducive to protecting the outer end wall 207.

[0040] The core 300 may further include at least one third outlet 640 (shown in Figure 4 ) that extends from the second pass 614 through the trailing edge 312 of the inner end wall 209 and into the hot gas flow path 232. In an exemplary embodiment, the core 300 includes a plurality of third outlets 640, each of which extends from the second pass 614 through the trailing edge 312 of the outer end wall 207 and into the hot gas flow path 232. The cooling fluid 240 discharged into the hot gas flow path 232 from the third outlet 640 may form a cooling film (not shown) on the trailing edge 312 of the outer end wall 207 that protects the trailing edge 312 of the outer end wall 207.

[0041] The core 300 may further include at least one fourth outlet 642 that extends from the turn 616 through the outer end wall 207 and into the hot gas flow path 232. In an exemplary embodiment, the core 300 includes a plurality of fourth outlets 642, each of which extends from the turn 616 through the trailing edge 312 of the outer end wall 207 and into the hot gas flow path 232. The cooling fluid 240 discharged into the hot gas flow path 232 from the fourth outlet 642 may form a cooling film (not shown) on the outer end wall 207 that is conducive to protecting the outer end wall 207. The core 300 may include the outlet 218 at any position that enables the core 300 to operate as described herein.

[0042] The size, shape, and relative position of the first outlet 636, the second outlet 638, the third outlet 640, and the fourth outlet 642 may be sized and arranged to facilitate tuning of the specific / desired pressure drop, volumetric flow rate, and / or heat transfer coefficient of the cooling fluid 240. For example, the first outlet 636 may have a first size, and the size of the second outlet 638 may be set to have a second size that is smaller than the first size of the first outlet 636. Thus, the first outlet 636 forms a cooling film (not shown) on the outer end wall 207, and the second outlet 638 supplements the cooling film with additional cooling fluid 240. Additionally, more outlets 636, 638, 640, and 642 facilitate reducing the volumetric flow rate of the cooling fluid 240 through the channel 600 and facilitate reducing the pressure drop of the cooling fluid 240 through the channel 600. Thus, the size, shape, and position of the first outlet 636, the second outlet 638, the third outlet 640, and the fourth outlet 642 may be sized and arranged to facilitate tuning of the pressure drop, volumetric flow rate, and / or heat transfer coefficient of the cooling fluid 240.

[0043] In an exemplary embodiment, each of the first tube pass 612 and the second tube pass 614 includes a plurality of turbulators or ridges 644 that create turbulence within the first tube pass 612 and the second tube pass 614. Specifically, the turbulators 644 create turbulence within the cooling fluid 240 to facilitate increasing the heat transfer coefficient of the cooling fluid 240 within the first tube pass 612 and the second tube pass 614. Increasing the heat transfer coefficient enhances the overall heat transfer between the cooling fluid 240 and the outer end wall 207. In an exemplary embodiment, the turbulators 644 have a height that is approximately 10% of the height of the third width 628 and the fourth width 634 (not shown). However, the turbulators 644 may have any other height that enables the core 300 to operate as described herein.

[0044] In an exemplary embodiment, the core 300 includes a plurality of hollow core tie straps 646 extending from a first inlet portion 606 to a second inlet portion 608 or from a first pass 612 to a second pass 614. Specifically, the core 300 includes at least one first core tie strap 648 extending from the first inlet portion 606 to the second inlet portion 608 and at least one second core tie strap 650 extending from the first pass 612 to the second pass 614. More specifically, in the exemplary embodiment, the core 300 includes a single first core tie strap 648 and a plurality of second core tie straps 650. The first core tie strap 648 and the second core tie strap 650, in which a fluid passage is defined, supplement a downstream portion of the passage 600 with the cooling fluid 240. As the cooling fluid 240 is conveyed through the passage 600, the temperature of the cooling fluid 240 increases, which is beneficial to reducing the heat transfer coefficient of the cooling fluid 240 and reducing the overall heat transfer between the cooling fluid 240 and the outer end wall 207. The core tie strap 646 is a "short cut segment" that conveys the cooling fluid 240 from an upstream portion of the passage 600 to a downstream portion of the passage 600 without heat transfer between the cooling fluid 240 and the outer end wall 207. Therefore, the temperature of the cooling fluid 240 conveyed through the core tie strap 646 is lower than the temperature of the cooling fluid 240 conveyed through the first pass 612, the second pass 614, and the turn 616. Therefore, the core tie strap 646 supplements the downstream portion of the passage 600 with the cooling fluid 240 having a lower temperature, which is beneficial to increasing the heat transfer coefficient of the cooling fluid 240 and enhancing the overall heat transfer between the cooling fluid 240 and the outer end wall 207. The core tie strap 646 can also be used as an inspection orifice to inspect the core 300.

[0045] During operation, inlets 602 and 604 receive coolant fluid 240 from coolant supply passage 233 and deliver coolant fluid 240 to first inlet section 606 and second inlet section 608. First inlet section 606 delivers a portion of coolant fluid 240 through first core strap 648 to supplement second inlet section 608. First inlet section 606 and second inlet section 608 merge into first pass 612 and each deliver coolant fluid 240 into first pass 612. First pass 612 delivers a portion of coolant fluid 240 through second core strap 650 to supplement second pass 614 and delivers another portion of coolant fluid 240 to turn 616. First pass 612 also delivers a portion of the coolant fluid through first outlet 636 into hot gas path 232 to form a coolant film on outer end wall 207. Turn 616 delivers a portion of coolant fluid 240 through fourth outlet 642 into hot gas path 232 to form a coolant film on outer end wall 207 and delivers the remaining coolant fluid 240 to second pass 614. Second pass 614 delivers coolant fluid 240 through second outlet 638 and third outlet 640 to supplement the coolant film and form a coolant film on trailing edge 312. As coolant fluid 240 is delivered through passage 600, it exchanges heat with outer end wall 207. Thus, coolant fluid 240 facilitates cooling of outer end wall 207 from within core 300 and forming a protective coolant film that protects outer end wall 207.

[0046] The serpentine configuration of passage 600 enables coolant fluid 240 to cool a greater area of outer end wall 207, thereby enhancing the overall heat transfer between coolant fluid 240 and outer end wall 207. Additionally, the serpentine orientation of passage 600 enables coolant fluid 240 to have a lower pressure approximately equal to the pressure of combustion gas 124 at throat 306. Further, the dimensions of widths 624, 626, 628, and 634 are sized to tune the pressure drop of coolant fluid 240 through passage 600 and facilitate enhancing the overall heat transfer between coolant fluid 240 and outer end wall 207. Additionally, outlet 618 delivers coolant fluid 240 into hot gas path 232 to protect outer end wall 207 by forming a coolant film. Additionally, core strap 646 supplements the downstream portion of passage 600 with coolant fluid 240. Thus, the arrangement of core 300 enhances the overall heat transfer between coolant fluid 240 and outer end wall 207.

[0047] Although Figures 3 to 6 core 300 and its features have been described in connection with outer end wall 207, it should be understood that core 300 can be used with similar features in inner end wall 209 to achieve similar results and benefits.

[0048] Figure 7It is a flowchart of an exemplary method 700 for cooling components of a rotating machine. In an exemplary embodiment, method 700 includes inserting a core into an inflatable chamber within a component. The core includes a channel that includes an inlet portion, at least one first pass, at least one second pass, and at least one turn between the respective first and second passes. The inlet portion includes a partition wall that separates a first inlet portion from a second inlet portion such that the inlet portion is a split-pass inlet. Method 700 further includes delivering 704 a cooling fluid flow into the first inlet portion and the second inlet portion. Method 700 further includes delivering 706 the cooling fluid flow from the first inlet portion and the second inlet portion into at least one first pass. The cooling fluid flow from the first inlet portion combines with the cooling fluid flow from the second inlet portion, and the at least one first pass delivers the cooling fluid flow in a first direction. Method 700 further includes delivering 708 the cooling fluid flow from the at least one first pass into at least one turn. The at least one turn changes the flow direction of the cooling fluid from the first direction to a second direction opposite the first direction. Method 700 further includes delivering 710 the cooling fluid flow from the at least one turn into at least one second pass. The at least one first pass, the at least one second pass, and the at least one turn are arranged such that the channel is a serpentine channel.

[0049] The above system relates to a serpentine core for cooling a portion of a hot gas path in a rotating machine. Specifically, in an exemplary embodiment, the rotating component includes an outer end wall formed in a nozzle of a turbine portion within the rotating machine. The outer end wall includes a core for cooling the outer end wall. The core includes a serpentine channel that includes an inlet portion, a first pass, a second pass, and a turn between the first and second passes. The inlet portion includes a partition wall that separates a first inlet portion from a second inlet portion such that a split-pass inlet is defined. The first pass, the second pass, and the turn include a plurality of outlets, each of which delivers cooling fluid from the core into the hot gas path to form a cooling film on the outer end wall. A plurality of hollow core straps deliver cooling fluid from an upstream portion of the core to a downstream portion of the core such that the downstream portion can be supplemented with cooler cooling fluid.

[0050] In an exemplary embodiment, a cooling fluid is conveyed through a first pass, a second pass, and a turn to facilitate convective cooling of an outer end wall from within a core. The serpentine configuration of the first pass, the second pass, and the turn enables the cooling fluid to convectively cool a larger area of the outer end wall, thereby enhancing the overall heat transfer between the cooling fluid and the outer end wall. Additionally, the serpentine configuration enables the cooling fluid to circulate at a lower pressure that is substantially equal to the pressure of the combustion gas at the nozzle throat. Further, the width of each of the first pass, the second pass, and the turn is selected to facilitate modifying or tuning the pressure drop of the cooling fluid passing through the first pass, the second pass, and the turn and to enhance the overall heat transfer between the cooling fluid and the outer end wall. Additionally, an outlet conveys the cooling fluid into a hot gas path to facilitate forming a cooling film on a stator end wall. Additionally, a core tie replenishes a downstream portion of the core with the cooling fluid. Thus, the core achieves both convective cooling of the end wall and film cooling of the end wall.

[0051] Additionally, exemplary technical effects of the systems and methods described herein include at least one of the following: (a) removing heat from a rotating machine component; (b) increasing the heat transfer coefficient of a cooling fluid; (c) enhancing the overall heat transfer between a cooling fluid and a rotating machine component; and (d) increasing the efficiency of a rotating machine.

[0052] Exemplary embodiments of systems and methods for cooling portions of a hot gas path of a rotating machine have been described in detail above. The systems and methods are not limited to the specific embodiments described herein, but rather the components of the systems and / or the steps of the methods may be used independently and separately from other components and / or steps described herein. For example, the method may also be used in combination with other turbine components and is not limited to being practiced only with portions of the hot gas path of a rotating machine as described herein. Rather, the exemplary embodiments may be implemented and used in conjunction with many other rotating machine applications.

[0053] Although specific features of various embodiments of the present disclosure may be shown in some figures and not in others, this is for convenience only. Any feature of any figure may be referenced and / or claimed in combination with any feature of any other figure in accordance with the principles of the embodiments of the present disclosure.

[0054] This written description uses examples to disclose embodiments of the present disclosure, including the best mode, and also enables any person skilled in the art to practice the embodiments of the present disclosure, including making and using any device or system and performing any combined method. The patentable scope of the embodiments described herein 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 that do not differ materially from the literal language of the claims.

Claims

1. A core (300) for cooling a component (207) used in a rotating machine (100), the core (300) comprising: A passage (600), the passage comprising: A first inlet portion (606); A second inlet portion (608); A partition wall (620) that separates the first inlet portion (606) from the second inlet portion (608) such that the first inlet portion (606), the second inlet portion (608), and the partition wall (620) define a split tube pass inlet (610); At least one first tube pass (612) for conveying a cooling fluid flow from the split tube pass inlet (610) in a first direction (630); At least one second tube pass (614) for conveying the cooling fluid flow in a second direction (632) that is substantially opposite to the first direction (630); and At least one turn (616) for changing the flow direction of the cooling fluid from the first direction (630) to the second direction (632), wherein the at least one first tube pass (612), the at least one second tube pass (614), and the at least one turn (616) are arranged such that the passage (600) defines a serpentine passage (600), Wherein the passage (600) further comprises a plurality of core tie straps (646) for conveying a portion of the cooling fluid flow from an upstream portion of the passage (600) to a downstream portion of the passage (600), The plurality of core tie straps (646) includes at least one first core tie strap (648) for conveying a portion of the cooling fluid flow from the first inlet portion (606) to the second inlet portion (608), The plurality of core tie straps (646) includes at least one second core tie strap (650) for conveying a portion of the cooling fluid flow from the first tube pass (612) to the second tube pass (614).

2. The core (300) according to claim 1, wherein the passage (600) includes at least one first inlet (602) for conveying the cooling fluid flow into the first inlet portion (606) and at least one second inlet (604) for conveying the cooling fluid flow into the second inlet portion (608).

3. The core (300) according to claim 1, wherein each of the first tube pass (612) and the second tube pass (614) includes a plurality of turbulators (644) for generating turbulence within the cooling fluid flow.

4. A gas turbine system (100), the gas turbine system comprising: A turbine section (108) fluidly coupled to a combustion system (106), wherein the turbine section (108) includes: An inner end wall (209) that circumscribes the longitudinal axis (126) of the gas turbine system (100); An outer end wall (207) that circumscribes the longitudinal axis (126) of the gas turbine system (100) and the inner end wall (209); A plurality of vanes (202) that extend between the outer end wall (207) and the inner end wall (209); and A core (300) positioned within at least one of the outer end wall (207) and the inner end wall (209) for cooling at least one of the outer end wall (207) and the inner end wall (209), the core (300) comprising: A passage (600) that comprises: A first inlet portion (606); A second inlet portion (608); A partition wall (620) that separates the first inlet portion (606) from the second inlet portion (608) such that the first inlet portion (606), the second inlet portion (608), and the partition wall (620) define a split tube pass inlet (610); At least one first tube pass (612) for conveying a cooling fluid flow from the split tube pass inlet (610) in a first direction (630); At least one second tube pass (614) for conveying a cooling fluid flow in a second direction (632) that is substantially opposite to the first direction (630); and At least one turn (616) for changing the flow direction of the cooling fluid from the first direction (630) to the second direction (632), wherein the at least one first tube pass (612), the at least one second tube pass (614), and the at least one turn (616) are arranged such that the passage (600) defines a serpentine passage (600), wherein the passage (600) further comprises a plurality of core straps (646) for conveying a portion of the cooling fluid flow from an upstream portion of the passage (600) to a downstream portion of the passage (600), the plurality of core straps (646) comprising at least one first core strap (648) for conveying a portion of the cooling fluid flow from the first inlet portion (606) to the second inlet portion (608), the plurality of core straps (646) comprising at least one second core strap (650) for conveying a portion of the cooling fluid flow from the first tube pass (612) to the second tube pass (614).

5. The gas turbine system (100) according to claim 4, wherein the passage (600) comprises a first inlet (602) for conveying the cooling fluid flow into the first inlet portion (606) and a second inlet (604) for conveying the cooling fluid flow into the second inlet portion (608).

6. The gas turbine system (100) according to claim 4, wherein adjacent ones of the plurality of vanes (202) define a throat (306) therebetween, and wherein the passage (600) further includes an upstream portion and a downstream portion, and wherein the upstream portion is located upstream of the throat (306) and the downstream portion is located downstream of the throat (306).

7. The gas turbine system (100) according to claim 4, wherein the passage (600) further includes a plurality of outlets (618) extending through the outer end wall (207).

8. The gas turbine system (100) according to claim 7, wherein the plurality of outlets (618) includes at least one first outlet (636) extending through the outer end wall (207) from the at least one first pass (612), and wherein a portion of the cooling fluid flow is conveyed through the at least one first outlet (636) to form a protective film on the outer end wall (207).

9. The gas turbine system (100) according to claim 7, wherein the plurality of outlets (618) includes at least one second outlet (638) extending through the outer end wall (207) from the at least one second pass (614), and wherein a portion of the cooling fluid flow is conveyed through the at least one second outlet (638) to form a protective film on the outer end wall (207).

10. The gas turbine system (100) according to claim 7, wherein the outer end wall (207) includes a trailing edge (224), and the plurality of outlets (618) includes at least one third outlet (640) extending through the trailing edge (224) from the at least one second pass (614), and wherein a portion of the cooling fluid flow is conveyed through the at least one third outlet (640) to form a protective film on the trailing edge (224).

11. The gas turbine system (100) according to claim 7, wherein the plurality of outlets (618) includes at least one fourth outlet (642) extending through the outer end wall (207) from the at least one turn (616), and wherein a portion of the cooling fluid flow is conveyed through the at least one fourth outlet (642) to form a protective film on the outer end wall (207).

12. A method (700) of cooling a component (207) of a rotating machine (100), the method (700) comprising: Insert the core (300) into the inflation chamber within the component (207). The core (300) includes a channel (600) that includes an inlet portion, at least one first pass (612), at least one second pass (614), and at least one turn (616). The inlet portion includes a first inlet portion (606), a second inlet portion (608), and a partition wall (620). The partition wall (620) separates the first inlet portion (606) from the second inlet portion (608) such that the inlet portion is a split-pass inlet (610). The channel (600) further includes a plurality of core straps (646) for conveying a portion of the cooling fluid flow from an upstream portion of the channel (600) to a downstream portion of the channel (600). The plurality of core straps (646) includes at least one first core strap (648) and at least one second core strap (650); Convey (704) the cooling fluid flow into the first inlet portion (606) and the second inlet portion (608); Convey (706) the cooling fluid from the first inlet portion (606) and the second inlet portion (608) into the at least one first pass (612), where the cooling fluid flow from the first inlet portion (606) merges with the cooling fluid flow from the second inlet portion (608), and where the at least one first pass (612) conveys the cooling fluid flow in a first direction (630); Convey (708) the cooling fluid flow from the at least one first pass (612) into the at least one turn (616), where the at least one turn (616) changes the flow direction of the cooling fluid from the first direction (630) to a second direction (632) opposite to the first direction (630); And Convey (710) the cooling fluid flow from the at least one turn (616) into the at least one second pass (614), where the at least one first pass (612), the at least one second pass (614), and the at least one turn (616) are arranged such that the channel (600) defines a serpentine channel (600), where the method further includes: conveying a portion of the cooling fluid flow from the first inlet portion (606) through the at least one first core strap (648) to supplement the second inlet portion (608), and conveying a portion of the cooling fluid flow from the at least one first pass (612) through the at least one second core strap (650) to supplement the at least one second pass (614).

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