Turbine nozzle with airfoils having curved trailing edges

Abstract

The present invention is entitled "Turbine nozzle with an airfoil having a curved trailing edge". The present invention discloses a turbine (10) that defines an axial direction (A), a radial direction (R) perpendicular to the axial direction (A), and a circumferential direction (C) extending concentrically around the axial direction (A). The turbine (10) includes a nozzle (202) having an inner platform (208), an outer platform (210), and an airfoil (212). The airfoil (212) includes a leading edge (218), a trailing edge (220) downstream of the leading edge (218), a pressure side surface (224), and a suction side surface (226) opposite the pressure side surface (224). The trailing edge (220) is orthogonal to the outer platform (210) in an axial-radial plane, and the trailing edge (220) is inclined relative to the inner platform in the axial-radial plane.

Description

Technical Field

[0001] The present disclosure relates generally to turbomachines. More particularly, the present disclosure relates to stator blades for turbomachines. Background Art

[0002] A gas turbine engine typically includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section gradually increases the pressure of the working fluid entering the gas turbine engine and supplies this compressed working fluid to the combustion section. The compressed working fluid and fuel (e.g., natural gas) are mixed in the combustion section and burned in a combustion chamber to generate high-pressure and high-temperature combustion gases. From the combustion section, the combustion gases flow into the turbine section, where they expand to produce work. For example, the expansion of the combustion gases in the turbine section can rotate a rotor shaft connected to, for example, a generator to generate electricity. The combustion gases then exit the gas turbine via the exhaust section.

[0003] The turbine section typically includes a plurality of stator blades, sometimes also referred to as nozzles. Each stator blade includes an airfoil positioned within the flow of combustion gases. The airfoil of the stator blade typically extends radially outward from an inner platform to an outer platform.

[0004] The airfoils may extend from a leading edge to a trailing edge downstream of the leading edge and may define aerodynamic surfaces therebetween, such as a pressure-side surface and a suction-side surface. The intersection of the aerodynamic surfaces with the inner and outer platforms may create regions of relatively high secondary losses. Some airfoils are provided with a curved shape to reduce such secondary losses; however, known curved shapes may result in other inefficiencies, such as inefficiencies due to increased throat spacing between the blades.

[0005] Therefore, an airfoil for a stator blade would be useful that provides both reduced secondary losses and efficient overall aerodynamic performance at the outer platform. Summary of the Invention

[0006] Aspects and advantages of the technology will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the technology.

[0007] According to one embodiment, an airfoil for a stator blade of a turbine is provided. The airfoil extends radially between an inner platform of the stator blade and an outer platform of the stator blade. The airfoil includes a leading edge extending on the airfoil from the inner platform to the outer platform in the direction of flow and a trailing edge downstream of the leading edge. The trailing edge extends on the airfoil from the inner platform to the outer platform. The airfoil also includes a pressure side surface extending between the inner platform and the outer platform and between the leading edge and the trailing edge. The airfoil also includes a suction side surface extending between the inner platform and the outer platform and between the leading edge and the trailing edge. The suction side surface is opposite to the pressure side surface. The trailing edge is orthogonal to the outer platform in the axial-radial plane, and the trailing edge is inclined relative to the inner platform in the axial-radial plane.

[0008] According to another embodiment, a turbine is provided. The turbine defines an axial direction, a radial direction perpendicular to the axial direction, and a circumferential direction extending concentrically around the axial direction. The turbine includes a compressor, a combustor disposed downstream of the compressor, and a turbine disposed downstream of the combustor. The turbine includes a stator blade having an inner platform, an outer platform, and an airfoil. The airfoil of the stator blade includes a leading edge extending along the flow direction from the inner platform to the outer platform on the airfoil and a trailing edge downstream of the leading edge. The trailing edge extends along the airfoil from the inner platform to the outer platform. The airfoil also includes a pressure side surface extending between the inner platform and the outer platform and between the leading edge and the trailing edge. The airfoil also includes a suction side surface extending between the inner platform and the outer platform and between the leading edge and the trailing edge. The suction side surface is opposite the pressure side surface. The trailing edge is orthogonal to the outer platform in the axial-radial plane and is inclined relative to the inner platform in the axial-radial plane.

[0009] These and other features, aspects and advantages of the present technology will become better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present technology and, together with the description, serve to explain the principles of the technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] A full and enabling disclosure of the technology, including the best mode thereof, to those skilled in the art is set forth in the description with reference to the accompanying drawings.

[0011] Figure 1 is a schematic diagram of an exemplary gas turbine engine according to one or more exemplary embodiments of the present disclosure;

[0012] Figure 2 is a perspective view of an exemplary turbine nozzle that may incorporate one or more embodiments of the present disclosure;

[0013] Figure 3is a side view of a trailing edge of an airfoil of a stator blade according to one or more exemplary embodiments of the present disclosure;

[0014] Figure 4 is an end view looking upstream of a stator blade according to a first exemplary embodiment of the present disclosure;

[0015] Figure 5 is an end view looking upstream of a stator blade according to a second exemplary embodiment of the present disclosure;

[0016] Figure 6 is an end view looking upstream of a stator blade according to a third exemplary embodiment of the present disclosure;

[0017] Figure 7 is a meridian side view of a stator blade according to one or more exemplary embodiments of the present disclosure;

[0018] Figure 8 yes Figure 7 A perspective view of the trailing edge of a stator blade;

[0019] Figure 9 is a meridian side view of a stator blade according to one or more exemplary embodiments of the present disclosure;

[0020] Figure 10 yes Figure 9 A perspective view of the trailing edge of a stator blade;

[0021] Figure 11 is a meridian side view of a stator blade according to one or more exemplary embodiments of the present disclosure;

[0022] Figure 12 yes Figure 11 A perspective view of the trailing edge of a stator blade;

[0023] Figure 13 is a meridian side view of a stator blade according to one or more exemplary embodiments of the present disclosure; and

[0024] Figure 14 yes Figure 13 Perspective view of the trailing edge of a stator blade.

[0025] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the technology. DETAILED DESCRIPTION

[0026] Reference will now be made in detail to embodiments of the present technology, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and alphabetical designations to refer to features in the drawings. Like or similar designations in the drawings and the specification have been used to refer to like or similar parts of the present technology. As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of the various components. The terms "upstream" and "downstream" refer to relative directions relative to the flow of a fluid in a fluid pathway. For example, "upstream" refers to the direction from which a fluid is flowing, and "downstream" refers to the direction toward which a fluid is flowing.

[0027] As used herein, approximate terms such as "substantially" or "about" include values within ten percent of the stated value. When used in the context of an angle or direction, such terms include values within ten degrees of the stated angle or direction. For example, "substantially vertical" includes directions within ten degrees of vertical in any direction (e.g., clockwise or counterclockwise).

[0028] Each example is provided by way of explanation of the present technology, not limitation of the present technology. In fact, it is obvious to those skilled in the art that modifications and variations can be made in the present technology without departing from the scope or spirit of the present disclosure. For example, a feature shown or described as part of one embodiment can be used on another embodiment to produce yet another embodiment. Therefore, the present technology is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0029] Although industrial or land-based gas turbines are shown and described herein, the technology of the present invention as shown and described herein is not limited to land-based and / or industrial gas turbines unless otherwise indicated in the claims. For example, the technology as described herein can be used with any type of turbine, including but not limited to aviation gas turbines (e.g., turbofans, etc.), steam turbines, and marine gas turbines.

[0030] Referring now to the drawings, in which like numerals refer to like elements throughout, Figure 1 A gas turbine engine 10 is schematically shown. It should be understood that the gas turbine engine 10 of the present disclosure need not be a gas turbine engine, but rather may be any suitable turbine, such as a steam turbine engine or other suitable engine. The gas turbine engine 10 may include an inlet section 12, a compressor section 14, a combustion section 16, a turbine section 18, and an exhaust section 20. The compressor section 14 and the turbine section 18 may be coupled by a shaft 22. The shaft 22 may be a single shaft or a plurality of shaft sections coupled together to form the shaft 22.

[0031] During operation, a working fluid, such as air 24, flows through the inlet section 12 and into the compressor 14, where the air 24 is gradually compressed, thereby providing compressed air 26 to the combustor 16. At least a portion of the compressed air 26 is mixed with fuel 28 within the combustor 16 and combusted to produce combustion gases 30. From the combustor 16, the combustion gases 30 flow into the turbine 18, where energy (kinetic and / or thermal energy) is transferred from the combustion gases 30 to the rotor blades, thereby rotating the shaft 22. The mechanical rotational energy can then be used for various purposes, such as powering the compressor 14 and / or generating electricity. The combustion gases 30 exiting the turbine 18 can then be exhausted from the gas turbine 10 via the exhaust section 20.

[0032] like Figures 3 to 14 As shown, the gas turbine 10 may define, for example, an axial direction A along or parallel to the shaft 22 , a radial direction R perpendicular to the axial direction A, and a circumferential direction C extending concentrically about the axial direction.

[0033] Figure 2 Provided are examples of methods that may be incorporated into various embodiments of the present disclosure. Figure 1 A perspective view of an exemplary turbine nozzle 202 in the turbine 18 is shown. Figure 2 As shown, in some embodiments, turbine nozzle 202 includes an inner platform 208 and an outer platform 210 radially spaced from inner platform 208 , eg, along radial direction R. The outer platform may extend along axial direction A between a forward sidewall 214 and an aft sidewall 216 .

[0034] exist Figure 2 In the illustrated example, a pair of fins 212 extends from the inner platform 208 across to the outer platform 210. In this regard, Figure 2 The exemplary turbine nozzle 202 shown is known in the industry as a doublet. However, the turbine nozzle 202 may have only one airfoil 212 (ie, a singlet), three airfoils 212 (ie, a triplet), or more airfoils 212.

[0035] Each airfoil 212 includes a leading edge 218 located at the front end of the airfoil 212 and a trailing edge 220 located at the rear end of the airfoil 212. The nozzle 202 may also include one or more rear hooks 222 configured to engage an adjacent cover (not shown) of a turbine (e.g., a gas turbine 10). For example, the nozzle 202 may include a rear hook 222 corresponding to each airfoil 212, e.g., a doublet may have two rear hooks 222.

[0036] Each airfoil 212 includes a pressure side surface 224 and an opposing suction side surface 226. The pressure side surface 224 and the suction side surface 226 are joined together or interconnected at a leading edge 218 of the airfoil 212, which is oriented into the flow of combustion gases 30 ( Figure 1 ). The pressure side surface 224 and the suction side surface 226 are also joined together or interconnected at the trailing edge 220 of the airfoil 212 spaced downstream from the leading edge 218. The pressure side surface 224 and the suction side surface 226 are continuous around the leading edge 218 and the trailing edge 220. The pressure side surface 224 is generally concave, and the suction side surface 226 is generally convex.

[0037] Figure 3 2 is a side view of the trailing edge portion of the airfoil 212 of the stator blade 202, wherein portions of the inner platform 208 and the outer platform 210 are shown in cross-section. The trailing edge portion may be the downstream half of the airfoil 212 at and around the trailing edge 220 of the airfoil 212. As shown in FIG. Figure 3 As can be seen in FIG, the trailing edge 220 intersects the inner platform 208 at a first point 228 and forms an interior angle β with the inner platform 208 at the first point 228. Figure 3 As can also be seen in FIG, the trailing edge 220 intersects the outer platform 210 at a second point 230 and forms an external angle α with the outer platform 210 at the second point 230. The second point 230 may be located downstream of the first point 228. Specifically, the second point 230 may be located downstream of a radial projection line 1000 extending along a radial direction R through the first point 228, as shown in FIG. Figure 3 shown.

[0038] In addition, as in Figure 3 As can be seen in the figure, in various embodiments, the trailing edge 220 protrusion in the axial-radial direction is a curve that bends like a bow in the downstream flow direction, wherein the outer diameter corner point 230 is not upstream of the inner diameter corner point 228, for example, in the example Figure 3 In some embodiments, the trailing edge 220 may be normal to the outer platform 210 and inclined to the inner platform 208. For example, the outer angle α may be approximately 90° and the inner angle β may not be equal to 90°, for example, the inner angle β may be less than 90°.

[0039] Figures 4 to 6 The embodiment of the vane 212 is shown as seen in a plane perpendicular to the axial direction A (e.g., a radial-circumferential plane defined by the radial direction R and the circumferential direction C). The direction of shaft rotation is counterclockwise (i.e., in Figures 4 to 6 Center to left.)

[0040] Figure 4is an end view looking upstream of the vane 212 of the stator blade 202 according to one or more exemplary embodiments. Figure 4 As seen in FIG, in some embodiments, the trailing edge 220 may be curved relative to the radial direction R, such as relative to a radial projection line 1000 extending through an intersection 228 of the trailing edge 220 with the inner platform 208, in such a manner that the pressure side 224 of each profile segment is positioned to be angled toward the center of the engine (e.g., toward the shaft 22 and / or its axial centerline) relative to an adjacent profile segment at a lower radius (e.g., closer to the inner platform 208).

[0041] In some embodiments, as Figure 4 As shown, an inner portion of the trailing edge 220 may be tangential to the radial direction R. An outer portion of the trailing edge 220 (eg, the intersection 230 of the trailing edge 220 and the outer platform 210 ) may be circumferentially offset from the radial projection line 1000 .

[0042] In other embodiments, Figure 5 As shown, the trailing edge 220 may be inclined relative to the radial direction R. For example, an inner portion of the trailing edge 220 may be tangent to a second line 1002 that is inclined at an angle Θ relative to the radial direction R, such as forming an angle Θ with the radial projection line 1000 .

[0043] In other embodiments, the trailing edge 220 may have an S-shape, such as Figure 6 As shown. The S-shape may have a compound curvature such that the outer portion of the trailing edge 220 is concave at the pressure side 224 and the inner portion of the trailing edge 200 is convex at the pressure side 224. Such an embodiment may include an inflection point in the curvature of the trailing edge 200, such as a change from convex to concave. In various embodiments, the inflection point may be located at or near the midpoint of the trailing edge 220 between the inner platform 208 and the outer platform 210, or may be located at or near one-third of the span, such as approximately one-third of the distance from the inner platform 208 to the outer platform 210.

[0044] Figures 7 to 14 Additional illustrations of further examples of airfoils 212 for stator blades 202 according to various embodiments of the present disclosure are provided. For simplicity and to more clearly depict the shape of the airfoil 212, the inner platform 208 and the outer platform 210 are not shown. Figures 7 to 14 Shown in.

[0045] For example, Figure 7 and Figure 8 An exemplary embodiment of an airfoil 212 is shown having a curved trailing edge 220 that is radially stacked in a manner that positions the pressure side 224 of each profile segment at an angle toward the center of the engine, e.g., as described above with respect to FIG. Figure 4 Additional examples of such radially stacked curved trailing edges 220 are shown in Figure 9 and Figure 10 The downstream arcuate portion of the curvature of the trailing edge 220, for example, as described above with respect to Figure 3 Said, in particular also in Figure 11 and Figure 12 as well as Figure 13 and Figure 14 See the exemplary embodiment shown.

[0046] The various examples shown and described herein are not mutually exclusive and may be provided in various combinations. For example, in some embodiments, the turbine may include a multi-stage nozzle, and one stage of the nozzle may have an airfoil 212, such as Figure 7 and Figure 8 As shown, another stage of the nozzle in the same turbine may have vanes 212, such as shown in FIG. Figure 9 and Figure 10 、 Figure 11 and Figure 12 and / or Figure 13 and Figure 14 shown.

[0047] This written description uses examples to disclose the technology, including the best mode, and also to enable any person skilled in the art to practice the technology, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the technology is defined by the claims and may include other examples that occur to those skilled in the art. If such other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims, such other examples are intended to be within the scope of the claims.

Claims

1. An airfoil (212) for a stator blade (202) of a turbine (10), the turbine defining an axial direction (A), a radial direction (R) perpendicular to the axial direction (A), and a circumferential direction (C) extending concentrically around the axial direction, the airfoil (212) extending radially between an inner platform (208) of the stator blade (202) and an outer platform (210) of the stator blade (202), the airfoil (212) comprising: a leading edge (218) extending on the airfoil (212) from the inner platform (208) to the outer platform (210); a trailing edge (220) located downstream of the leading edge (218) in the direction of flow, the trailing edge (220) extending on the airfoil (212) from the inner platform (208) to the outer platform (210); a pressure side surface (224) extending between the inner platform (208) and the outer platform (210) and between the leading edge (218) and the trailing edge (220); and a suction side surface (226) extending between the inner platform (208) and the outer platform (210) and between the leading edge (218) and the trailing edge (220), the suction side surface (226) being opposite the pressure side surface (224); wherein the trailing edge (220) intersects the inner platform (208) at a first point (228) and intersects the outer platform (210) at a second point (230), wherein the trailing edge (220) is orthogonal to the outer platform (210) in an axial-radial plane at the second point and the trailing edge (220) is inclined relative to the inner platform (208) in the axial-radial plane at the first point, wherein the trailing edge defines an S-shape in a radial-circumferential plane, and wherein the S-shape has a compound curvature such that an outer portion of the trailing edge is concave at the pressure side surface and an inner portion of the trailing edge is convex at the pressure side surface, the outer portion extending from the outer platform to an inflection point located near a midpoint of the trailing edge and the inner portion extending from the inflection point to the inner platform.

2. The airfoil (212) of claim 1, wherein the trailing edge (220) forms an angle with the inner platform (208) in the axial-radial plane that is less than ninety degrees.

3. The airfoil (212) of claim 1, wherein the trailing edge (220) curves outwardly along the flow direction between the first point (228) and the second point (230).

4. The airfoil (212) of claim 1, wherein the second point (230) is not upstream of the first point (228).

5. The airfoil (212) of claim 1, wherein the second point (230) is located downstream of the first point (228).

6. The airfoil (212) of claim 1, wherein the trailing edge (220) is curved in a plane perpendicular to the axial direction (A).

7. The airfoil (212) of claim 6, wherein the trailing edge (220) is curved in the plane perpendicular to the axial direction (A) in such a way that the pressure side surface (224) of the airfoil (212) is angled toward the center of the turbine (10).

8. The airfoil (212) of claim 6, wherein an inner portion of the trailing edge (220) is tangential to the radial direction (R).

9. The airfoil (212) of claim 6, wherein an inner portion of the trailing edge (220) is inclined relative to the radial direction (R).

10. A turbine (10), the turbine defining an axial direction (A), a radial direction (R) perpendicular to the axial direction (A), and a circumferential direction (C) extending concentrically around the axial direction, the turbine (10) comprising: compressor (14); a burner (16) disposed downstream of the compressor (14); and A turbine (18) is arranged downstream of the combustor (16), the turbine (18) comprising a stator blade (202) having an inner platform (208), an outer platform (210) and an airfoil (212), the airfoil of the stator blade being as claimed in any one of claims 1 to 9.

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