Turbine blade including internal cooling

Abstract

A turbine blade (200) includes a root (202), a platform (204) connected to the root, an airfoil (206) including a pressure side (222) and a suction side (224) that extend between a leading edge (218) and a trailing edge (220) and cooperate to define a hollow blade interior. The pressure side and the suction side extend from the platform to the blade tip to define an airfoil length. A main cooling channel (304) has an inlet (308) and an outlet (320) adjacent the platform (204) and extends from the platform toward the blade tip. A flow blocker (316) is disposed within the main cooling channel (304) and extends from the platform toward the blade tip to a wall tip (318) between one percent and ten percent of the airfoil length, the flow blocker (316) cooperating with the main cooling channel (304) to define a U-shaped flow path (322).

Description

Docket No. 2024PF00360TURBINE BLADE INCLUDING INTERNAL COOLING BACKGROUND

[0001] Turbine blades with internal cooling are used in many gas turbine engines to allow operation at higher temperatures. These blades are subjected to thermal and mechanical stress due to the high-temperature combustion gases they encounter. To counter this, cooling techniques are employed, including internal cooling channels that facilitate heat transfer. These channels are designed to circulate cooler air, typically extracted from the compressor, through the interior of the blades.

[0002] Various cooling methods may be employed, such as impingement cooling, film cooling, and convection cooling through serpentine passages. These techniques work to cool the blade and extend the service life of the blades. The effectiveness of internal cooling directly influences the efficiency of the turbine, as it enables higher turbine inlet temperatures, thus improving thermal efficiency and power output.SUMMARY

[0003] In one aspect, a turbine blade includes a root, a platform connected to the root, an airfoil including a pressure side and a suction side that extend between a leading edge and a trailing edge and cooperate to define a hollow blade interior. A blade tip, the pressure side, and the suction side extending from the platform to the blade tip to define an airfoil length. A main cooling channel has an inlet and an outlet adjacent the platform and extends from the platform toward the blade tip. A flow blocker is disposed within the main cooling channel and extends from the platform toward the blade tip to a wall tip between one percent and ten percent of the airfoil length, the flow blocker cooperating with the main cooling channel to define a U-shaped flow path.Docket No. 2024PF00360

[0004] In another aspect, a turbine blade includes a platform, and an airfoil extending from the platform to a blade tip to define an airfoil length, the airfoil enclosing a main cooling channel and a trailing portion cooling region. A flow blocker is disposed within the main cooling channel and extends from the platform toward the blade tip to a wall tip. The flow blocker cooperates with the main cooling channel to define a U-shaped flow path that extends from an inlet to an outlet positioned adjacent the platform. A plurality of pin members is formed within the trailing portion cooling region, the outlet of the flow blocker defining an inlet to the trailing portion cooling region.

[0005] In yet another aspect, a method of cooling a turbine blade includes forming a main cooling channel in an airfoil of the turbine blade, the main cooling channel extending between a platform and a blade tip, and forming a trailing portion cooling region between the main cooling channel and a trailing edge of the airfoil. The method also includes directing a flow of cooling gas into the main cooling channel through an inlet, a first portion of the cooling gas flowing through an outlet and the remainder of the cooling gas flowing toward the blade tip. The method further includes positioning a flow blocker between the inlet and the outlet to divert the first portion of the cooling gas into a U-shaped flow path from the inlet to the outlet, the flow blocker extending between the platform and the blade tip to a wall tip, and guiding the flow of cooling gas from the outlet into the trailing portion cooling region.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0007] FIG. 1 is a longitudinal cross-sectional view of a gas turbine engine taken along a plane that contains a longitudinal axis or central axis.

[0008] FIG. 2 is a perspective view of a turbine blade suitable for use as a rotating blade in the gas turbine engine of Fig. 1.

[0009] FIG. 3 is a perspective view of the turbine blade of FIG. 2 with a pressure side face removed to illustrate a cooling flow path.Docket No. 2024PF00360

[0010] FIG. 4 is an enlarged perspective view of a portion of the turbine blade of FIG. 3 better illustrating a flow blocker.

[0011] FIG. 5 is a perspective view of a portion of a casting core suitable for use in forming the cooling flow path illustrated in FIG. 3 and FIG. 4.DETAILED DESCRIPTION

[0012] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following 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.

[0013] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0014] It should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms “including,” “having,” and “comprising,” as well as derivatives thereof, mean inclusion without limitation. The singular forms “a”, “an” and “the” are intended to include the plural forms (i.e., one or more) as well, unless the context clearly indicates otherwise. Further, the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more ofDocket No. 2024PF00360 the associated listed items. The term “or” is inclusive, meaning and / or, unless the context clearly indicates otherwise. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0015] Also, terms such as “first”, “second”, “third” and so forth may be used herein to refer to various elements, information, functions, or acts, but should not be considered as limiting in any way. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0016] In addition, the term “adjacent to” may mean that an element is relatively near to but not in contact with a further element or that the element is in contact with the further portion unless the context clearly indicates otherwise. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms “about” or “substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard is available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

[0017] FIG. 1 illustrates an example of a gas turbine engine 100 including a compressor section 102, a combustion section 104, and a turbine section 106 arranged along a central axis 108. The compressor section 102 includes a plurality of compressor stages 110 with each compressor stage 110 including a set of rotating blades 112 and a set of stationary vanes 114 or adjustable guide vanes. A rotor 116 supports the rotating blades 112 for rotation about the central axis 108 during operation. In some constructions, a single one-piece rotor 116 extends the length of the gas turbine engine 100 and is supported for rotation by a bearing at either end. In other constructions, the rotor 116 is assembled from several separate spools that are attachedDocket No. 2024PF00360 to one another or may include multiple disk sections that are attached via a bolt or plurality of bolts.

[0018] The compressor section 102 is in fluid communication with an inlet section 118 to allow the gas turbine engine 100 to draw atmospheric air into the compressor section102. During operation of the gas turbine engine 100, the compressor section 102 draws in atmospheric air and compresses that air for delivery to the combustion section 104. The illustrated compressor section 102 is an example of one compressor section 102 with other arrangements and designs being possible.

[0019] In the illustrated construction, the combustion section 104 includes a plurality of separate combustors 120 that each operate to mix a flow of fuel with the compressed air from the compressor section 102 and to combust that air-fuel mixture to produce a flow of high temperature, high pressure combustion gases or exhaust gas 122. Of course, many other arrangements of the combustion section 104 are possible.

[0020] The turbine section 106 includes a plurality of turbine stages 124 with each turbine stage 124 including a number of rotating blades and a number of stationary blades or vanes. The turbine stages 124 are arranged to receive the exhaust gas 122 from the combustion section 104 at a turbine inlet 126 and expand that gas to convert thermal and pressure energy into rotating or mechanical work. The turbine section 106 is connected to the compressor section 102 to drive the compressor section 102. For gas turbine engines 100 used for power generation or as prime movers, the turbine section 106 is also connected to a generator, pump, or other device to be driven. As with the compressor section 102, other designs and arrangements of the turbine section 106 are possible.

[0021] A control system 128 is coupled to the gas turbine engine 100 and operates to monitor various operating parameters and to control various operations of the gas turbine engine 100. In preferred constructions the control system 128 is typically micro-processor based and includes memory devices and data storage devices for collecting, analyzing, and storing data. In addition, the control system 128 provides output data to various devices including monitors, printers, indicators, and the like that allow users to interface with the control system 128 to provide inputs or adjustments. In the example of a power generation system, a user mayDocket No. 2024PF00360 input a power output set point and the control system 128 may adjust the various control inputs to achieve that power output in an efficient manner.

[0022] The control system 128 can control various operating parameters including, but not limited to variable inlet guide vane positions, fuel flow rates and pressures, engine speed, valve positions, generator load, and generator excitation. Of course, other applications may have fewer or more controllable devices. The control system 128 also monitors various parameters to assure that the gas turbine engine 100 is operating properly. Some parameters that are monitored may include inlet air temperature, compressor outlet temperature and pressure, combustor outlet temperature, fuel flow rate, generator power output, bearing temperature, and the like. Many of these measurements are displayed for the user and are logged for later review should such a review be necessary.

[0023] FIG. 2 illustrates a turbine blade 200 that is suitable for use as a rotating blade 112 in the gas turbine engine 100 of FIG. 1. The turbine blade 200 includes a root 202, a platform 204, an airfoil 206, and a blade tip 208. The root 202 includes one or more hooks, lobs, teeth, or other attachment features that are arranged to facilitate attachment of the turbine blade 200 to the rotor 116.

[0024] In describing the turbine blade 200, directions such as radial 210, axial 212, and tangential 214 will be used. These terms are relative to the longitudinal or rotational axis of the turbine engine 100. In addition, terms such as top or bottom may also be used with top corresponding to radial outermost and bottom relating to radially innermost.

[0025] The platform 204 is positioned on top of the root 202 and defines an interface between the root 202 and the airfoil 206. The platform 204 can take any shape desired for the particular turbine blade 200.

[0026] The airfoil 206 extends radially from the platform 204 to the blade tip 208 to define an airfoil length 216. The airfoil 206 is formed from a leading edge 218, a trailing edge 220, a pressure side 222 that extends from the leading edge 218 to the trailing edge 220, and a suction side 224 that extends from the leading edge 218 to the trailing edge 220. The shape of the airfoil 206 is selected to meet the requirements of the particular application. Many parameters can affect the desired shape of the airfoil 206 as is well understood. The shape of the pressure side 222 and the suction side 224 cooperate to define a camber line 226 that extends from theDocket No. 2024PF00360 leading edge 218 to the trailing edge 220. The camber line 226 is the curve that passes through the airfoil 206 and is equally spaced from the pressure side 222 and the suction side 224 along its length, thereby effectively representing the average curvature of the airfoil 206.

[0027] Some turbine blades 200 are exposed to high-temperature fluid that contacts the platform 204 and the airfoil 206 which in turn heats the turbine blade 200. To assure a desired lifetime for the turbine blade 200 as well as to allow for higher temperature operation, the turbine blade 200 may include internal cooling features. While discussed in greater detail with regard to the following figures, the turbine blade 200 includes internal cooling features in the root 202, the platform 204, and the airfoil 206. In fact, the turbine blade 200 illustrated in FIG.2 includes cooling flow outlets 228 at the trailing edge 220 of the airfoil 206 and film cooling outlets 230 at the leading edge 218 of the airfoil 206. Of course, other arrangements of turbine blades 200 may omit one or both of the cooling flow outlets 228 and the film cooling outlets 230 as well as very their shape, arrangement, and / or quantity.

[0028] FIG. 3 illustrates a section view of the portion of the turbine blade 200 of FIG. 2 within box 3-3 and taken along the camber line 226 of the turbine blade 200. The illustrated turbine blade 200 includes one arrangement of a rear cooling path 302 with many different arrangements being possible.

[0029] The rear cooling path 302 includes a main cooling channel 304 and a trailing portion cooling region 306. The main cooling channel 304 includes an inlet 308, a solid wall 310 that extends substantially radially from the root 202 to a point near the blade tip 208, and a separator wall 312 that extends substantially radially from a point near the platform 204 or the root 202 to a point near the blade tip 208. The solid wall 310 operates to define the separation between a forward portion of the turbine blade 200 and the rear cooling path 302 within the root 202 and the airfoil 206.

[0030] The separator wall 312 is a perforated wall that includes a plurality of apertures or perforations spaced apart along the length of the separator wall 312. The perforations allow for the flow of coolant out of the main cooling channel 304 and into the trailing portion cooling region 306 along the length of the separator wall 312. In addition, a plurality of ribs 314 is positioned within the main cooling channel 304 and operates to create turbulence andDocket No. 2024PF00360 additional surface area in the cooling flow within the main cooling channel 304 to further enhance heat transfer.

[0031] In addition to passing through the separator wall 312, portions of the cooling fluid in the rear cooling path 302 pass over the top, or radially outermost point on the separator wall 312 and under the bottom, or radially innermost point of the separator wall 312 to enter the trailing portion cooling region 306. The arrangement of the rear cooling path 302 is such that the least resistant flow path for the coolant is under the bottom of the separator wall 312. To inhibit, reduce, and control this portion of coolant flow, a flow blocker 316 is provided.

[0032] The flow blocker 316 extends from the platform 204 or root 202 radially toward a wall tip 318. The wall tip 318 is generally positioned between one percent and ten percent of the airfoil length 216 with longer flow blockers 316 being possible. The position of the wall tip 318 is selected to provide the desired flow of coolant under the separator wall 312 while still providing sufficient flow along the full airfoil length 216.

[0033] FIG. 4 is an enlarged view of the portion of the turbine blade 200 of FIG. 3 taken around the flow blocker 316 to better illustrates the arrangement of the flow blocker 316.

[0034] The flow blocker 316 is integrally formed or formed as part of the turbine blade 200 and includes a curved wall 402, or curved portion that partially defines the outlet 320 for the main cooling channel 304 and a planar or substantially planar wall 404 or upstream wall that defines a portion of the inlet 308 of the main cooling channel 304. The wall tip 318 connects the curved wall 402 and the planar wall 404. In the illustrated construction, the wall tip 318 is semi-cylindrical and therefore semi-circular in cross section.

[0035] The flow blocker 316 is positioned and sized to force the flow of coolant to follow a U-shaped flow path 322 in order to go directly from the inlet 308 to the outlet 320. This additional flow length reduces the quantity of fluid that follows this direct path from the main cooling channel 304 to the trailing portion cooling region 306. In addition, the curved wall 402 or downstream wall cooperates with the separator wall 312 to form the outlet 320 in a converging shape or converging nozzle to direct the flow of coolant into the trailing portion cooling region 306. Selecting the length of the flow blocker 316, or the radial position of the wall tip 318 controls the amount of flow that passes directly from the inlet 308, along the U-Docket No. 2024PF00360 shaped flow path 322, and out the outlet 320. A longer flow blocker 316 results in a lower flow following this path, while a shorter flow blocker 316 allows for an increased flow.

[0036] Once the coolant flow passes through the separator wall 312, above the separator wall 312, or below the separator wall 312, the coolant follows any serpentine path 406 around various pin members 324 until it ultimately exits the trailing edge 220 via the cooling flow outlets 228.

[0037] As one of ordinary skill will realize, the length of the flow blocker 316 as well as the shape of the flow blocker 316 may vary as desired to achieve the desired level of flow along the U-shaped flow path 322. For example, some constructions employ a curved wall 402 that is made up of a planar portion and a curved portion to allow for a longer flow blocker 316.

[0038] In order to form the flow blocker 316 as part of the turbine blade 200, the turbine blade 200 is sometimes formed using a casting process. As part of this process, a casting core 500, shown in FIG. 5 may be used. The casting core 500 takes up space during the casting process such that the casting core 500 defines voids. In the illustration of FIG. 5, any gaps or openings around the casting core 500 are filled with material during the casting process, and the space occupied by the core becomes voids, apertures, or open spaces.

[0039] The casting core 500 includes a solid wall space 502, a flow blocker space 504, a separator wall space 506, and a plurality of pin member spaces 508. The solid wall space 502, the flow blocker space 504, and each of the pin member spaces 508 are sized and arranged such that during the casting process, the various spaces are filled with material to define the solid wall 310, the flow blocker 316, and each of the pin members 324. The separator wall space 506 includes a plurality of solid cylindrical portions that extend across the separator wall space 506. During the casting process, the empty portions of the separator wall space 506 are filled with material while the cylindrical portions block the material to define perforations or apertures through the formed separator wall 312.

[0040] Once the casting process is complete, the casting core 500 is removed, dissolved, or otherwise destroyed to complete the casting process. Additional machining, fabrication, or processes may then be performed as necessary to complete the manufacture of the turbine blade 200.Docket No. 2024PF00360

[0041] Of course, other processes, including but not limited to additive manufacturing processes may be used in place of or in conjunction with the casting process as desired.

[0042] In operation, the turbine blade 200 is formed to include the internal cooling arrangement described with regard to FIG. 3 and FIG. 4 or a similar arrangement. A flow of coolant or cooling gas is directed along the rear cooling path 302 to cool the rear portion of the airfoil 206. The coolant or cooling flow enters the main cooling channel 304 via the inlet 308. The flow blocker 316 acts to inhibit flow directly from the inlet 308 to the outlet 320 via the Ilshaped flow path 322 to control the amount of flow that follows this path. Most of the flow continues radially outward (or upward) in the main cooling channel 304 with portions of the flow exiting the main cooling channel 304 and entering the trailing portion cooling region 306 via each aperture in the separator wall 312. Whatever coolant flow remains, passes over the top of the separator wall 312 to exit the main cooling channel 304 and enter the trailing portion cooling region 306. All the flow within the trailing portion cooling region 306 follows one of a plurality of serpentine paths 406 to further cool the airfoil 206 before ultimately exiting the airfoil via the cooling flow outlets 228 formed in or near the trailing edge 220.

[0043] The placement and sizing of the flow blocker 316 allows for precise control of the quantity of flow that passes under the separator wall 312 and flows directly from the inlet 308, along the U-shaped flow path 322, to the outlet 320. The flow blocker 316 can be formed as part of the turbine blade 200 during a casting, or other manufacturing process such that it does not greatly increase the cost of the turbine blade 200.

[0044] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

[0045] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowedclaims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

Claims

Docket No. 2024PF00360CLAIMSWhat is claimed is:

1. A turbine blade comprising:a root;a platform connected to the root;an airfoil including a pressure side and a suction side that extend between a leading edge and a trailing edge and cooperate to define a hollow blade interior;a blade tip, the pressure side and the suction side extending from the platform to the blade tip to define an airfoil length;a main cooling channel having an inlet and an outlet adjacent the platform, the main cooling channel extending between the platform and the blade tip; anda flow blocker disposed within the main cooling channel and extending from the platform toward the blade tip to a wall tip between one percent and ten percent of the airfoil length, the flow blocker cooperating with the main cooling channel to define a U-shaped flow path.

2. The turbine blade of claim 1, wherein the flow blocker includes an upstream wall, a downstream wall, and the wall tip that is curved and extends between the upstream wall and the downstream wall.

3. The turbine blade of claim 2, wherein the wall tip is a semi-cylinder.

4. The turbine blade of claim 2, further comprising a separator wall formed between the main cooling channel and a trailing portion cooling region, the separator wall and the downstream wall forming the outlet.

5. The turbine blade of claim 4, wherein the separator wall includes a plurality of flow openings, each flow opening providing fluid communication between the main cooling channel and the trailing portion cooling region.

6. The turbine blade of claim 4, wherein the downstream wall and the separator wall cooperate to define a converging nozzle.Docket No. 2024PF00360 7. The turbine blade of claim 4, further comprising a plurality of pin members formed in the trailing portion cooling region, the plurality of pin members cooperating to define a plurality of trailing region flow paths.

8. A turbine blade comprising:a platform;an airfoil extending from the platform to a blade tip to define an airfoil length, the airfoil enclosing a main cooling channel and a trailing portion cooling region;a flow blocker disposed within the main cooling channel and extending from the platform toward the blade tip to a wall tip, the flow blocker cooperating with the main cooling channel to define a U-shaped flow path that extends from an inlet to an outlet positioned adjacent the platform; anda plurality of pin members formed within the trailing portion cooling region, the outlet of the flow blocker defining an inlet to the trailing portion cooling region.

9. The turbine blade of claim 8, wherein the flow blocker includes an upstream wall, a downstream wall, and a wall tip that is curved and extends between the upstream wall and the downstream wall.

10. The turbine blade of claim 9, wherein the downstream wall includes a planar portion and a curved portion.

11. The turbine blade of claim 9, further comprising a separator wall formed between the main cooling channel and the trailing portion cooling region, the separator wall and the downstream wall forming the outlet.

12. The turbine blade of claim 11, wherein the separator wall includes a plurality of flow openings, each flow opening providing fluid communication between the main cooling channel and the trailing portion cooling region.

13. The turbine blade of claim 11, wherein the downstream wall and the separator wall cooperate to define a converging nozzle.Docket No. 2024PF00360 14. A method of cooling a turbine blade, the method comprising:forming a main cooling channel in an airfoil of the turbine blade, the main cooling channel extending between a platform and a blade tip;forming a trailing portion cooling region between the main cooling channel and a trailing edge of the airfoil;directing a flow of cooling gas into the main cooling channel through an inlet, a first portion of the cooling gas flowing through an outlet and the remainder of the cooling gas flowing toward the blade tip;positioning a flow blocker between the inlet and the outlet to divert the first portion of the cooling gas into a U-shaped flow path from the inlet to the outlet, the flow blocker extending between the platform and the blade tip to a wall tip; andguiding the flow of cooling gas from the outlet into the trailing portion cooling region.

15. The method of claim 14, further comprising forming an upstream wall, a downstream wall, and a wall tip that is curved and extends between the upstream wall and the downstream wall to define the flow blocker.

16. The method of claim 15, further comprising forming the wall tip as a semicylinder.

17. The method of claim 15, further comprising positioning a separator wall between the main cooling channel and the trailing portion cooling region to form the outlet.

18. The method of claim 17, further comprising forming a plurality of apertures in the separator wall, the apertures arranged to direct a portion of the remainder of the cooling gas from the main cooling channel to the trailing portion cooling region.

19. The method of claim 17, further comprising forming a converging nozzle between the downstream wall and the separator wall.

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