Blade for gas turbine and gas turbine

Abstract

The invention relates to the technical field of gas turbine blade cooling, in particular to a blade for a gas turbine and the gas turbine, the end, connected with a turbine of the gas turbine, of the blade is a blade root, the end, away from the blade root, of the blade is a blade top, the edge of the blade top is provided with a convex shoulder extending in the circumferential direction, and a groove is defined by the convex shoulder and the blade top; the convex shoulders comprise a pressure side convex shoulder and a suction side convex shoulder; a cooling hole is formed in the bottom wall of the groove and is used for outputting a cooling working medium to cool the blade top; the top width of the suction side convex shoulder is smaller than the bottom width of the suction side convex shoulder, so that a cooling working medium can flow to the top of the suction side convex shoulder from the cooling hole in the process that the blade rotates along with a turbine of the gas turbine; the gas turbine comprises a gas compressor, a combustion chamber and a turbine provided with the blade.

Description

Technical Field

[0001] The present disclosure relates to the technical field of gas turbine blade cooling, and more specifically, to a blade for a gas turbine and a gas turbine. Background Art

[0002] A gas turbine is an efficient, environmentally friendly, and reliable energy conversion device, which is widely used in power generation, transportation, industrial fields, military fields, distributed energy, and other fields. A gas turbine can convert the chemical energy of fuel into mechanical energy, thereby providing power output. Compared with traditional energy conversion devices such as steam turbines and internal combustion engines, gas turbines have higher thermal efficiency and lower emissions. Therefore, gas turbines play an important role in the field of energy conversion and utilization.

[0003] However, the thermal efficiency of a gas turbine is affected by various factors, such as the type of fuel, the fuel-air mixing ratio, the design of the gas turbine, operating conditions, etc. In practical applications, in order to improve the thermal efficiency of a gas turbine, the most direct means is to increase the gas temperature at the turbine inlet. However, currently, the temperature of the high-energy gas reaches up to 1600°C when it enters the turbine, which is much higher than the normal operating temperature of the turbine blade. Cooling technology needs to be adopted to maintain the normal operation of the blade.

[0004] In the prior art, generally, a composite cooling technology is used to cool the blade body and the outer surface. Due to the special position of the blade tip, its cooling effect and leakage loss are both affected by the structure at the blade tip. Therefore, the improvement of it is the current key and difficult point. Currently, a shoulder-groove structure is usually designed at the blade tip, which can effectively improve the film cooling efficiency in the groove area. However, since the top of the shoulder will be subjected to a greater scouring force from the gas, resulting in a higher heat load, therefore, how to improve the cooling effect of the top of the blade shoulder has become a technical problem to be solved urgently. Summary of the Invention

[0005] In view of the above problems, the present disclosure provides a blade for a gas turbine and a gas turbine, which is beneficial to the migration of the cooling medium to the top of the shoulder, improves the cooling effect of the top of the suction-side shoulder, and further improves the thermal efficiency of the gas turbine.

[0006] To achieve the above object, the present disclosure provides a blade for a gas turbine. One end of the blade connected to the turbine of the gas turbine is the blade root, and the end far from the blade root is the blade tip. It is characterized in that a circumferentially extending shoulder is provided at the edge of the blade tip, and the shoulder and the blade tip enclose a groove; the shoulder includes a pressure-side shoulder extending from the pressure side of the blade and a suction-side shoulder extending from the suction side of the blade; cooling holes are formed on the bottom wall of the groove, which are adapted to output a cooling working medium to cool the blade tip; the width of the top of the suction-side shoulder is smaller than the width of the bottom of the suction-side shoulder, so as to facilitate the flow of the cooling working medium from the cooling holes to the top of the suction-side shoulder during the rotation of the blade with the turbine of the gas turbine.

[0007] In a schematic embodiment, the width of the top of the pressure-side shoulder is smaller than the width of the bottom of the pressure-side shoulder.

[0008] In a schematic embodiment, the inner side walls of the pressure-side shoulder and the suction-side shoulder form an inclination angle a with the vertical direction, and 0° < a < 90°.

[0009] In a schematic embodiment, the inner side walls of the pressure-side shoulder and the suction-side shoulder are configured as arc-shaped walls recessed towards the shoulder, and the secant line of the arc-shaped wall forms an angle b with the vertical direction, which satisfies 0° < b < 90°.

[0010] In a schematic embodiment, the outer side wall of the shoulder is flush with the outer surface of the blade.

[0011] In a schematic embodiment, the blade rotates with the turbine of the gas turbine along a preset direction; the depth of the groove is H, the height of the pressure-side shoulder is h, and 0 ≤ h ≤ H, and the height of the suction-side shoulder is equal to the depth of the groove.

[0012] In a schematic embodiment, the top width of the shoulder is w, the diameter of the cooling hole is D, and the blade length is L, 0.01L ≤ w ≤ 0.04L, 0.005L ≤ D ≤ 0.01L.

[0013] In a schematic embodiment, one end of the blade close to the working gas inlet is the leading edge, and one end close to the working gas outlet is the trailing edge; the width of the shoulder at the leading edge is greater than the width of the shoulder at the trailing edge.

[0014] In a schematic embodiment, the depth of the groove is H, and the chord length of the blade is L, 0.01L ≤ H ≤ 0.04L.

[0015] The present disclosure also provides a gas turbine, including a compressor adapted to compress air;

[0016] a combustion chamber capable of mixing and igniting fuel with compressed air to generate combustion gas; and a turbine equipped with the blade according to any one of claims 1-9, wherein the impact of the combustion gas on the blade drives the turbine to rotate, so as to convert the energy of the combustion gas into the kinetic energy of the turbine.

[0017] For the blade for a gas turbine provided by the present invention, the cooling working medium is ejected from the cooling holes to cool the bottom of the groove; as the blade rotates, the cooling working medium gradually flows to the suction side shoulder and detaches from the blade after passing through the top of the suction side shoulder. Since the width of the top of the suction side shoulder is smaller than that of the bottom, it can make the cooling working medium flow more smoothly during the process of flowing from the groove to the top of the suction side shoulder, effectively alleviating the phenomenon that the cooling working medium stays at the connection between the bottom wall of the groove and the inner wall of the suction side shoulder to form a dead zone, and improving the cooling efficiency of the top of the suction side shoulder; based on the same inventive concept, the present invention also provides a gas turbine, on which the above-mentioned blade is installed. After obtaining a better cooling effect at the top of the suction side shoulder of the blade, the thermal efficiency of the gas turbine can also be improved to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Through the following description of the embodiments of the present invention with reference to the drawings, the above content and other objects, features and advantages of the present disclosure will become clearer. In the drawings:

[0019] Figure 1 is a three-dimensional view of a blade for a gas turbine provided by the present invention;

[0020] Figure 2 is Figure 1 a schematic plan view at the blade tip in the illustrated schematic embodiment;

[0021] Figure 3 is Figure 1 a three-dimensional streamline diagram of the blade tip in the illustrated schematic embodiment;

[0022] Figure 4 is Figure 2 a schematic cross-sectional view taken along line A-A in ;

[0023] Figure 5 is a schematic cross-sectional view taken along line A-A in another embodiment provided by the present invention;

[0024] Figure 6 is a comparison diagram of the average cooling efficiency at the top of the suction side shoulder between the prior art and the embodiment provided by the present invention.

[0025] In the above drawings, the meanings of the reference numerals are specifically as follows:

[0026] 1. Blade root;

[0027] 2. Blade tip;

[0028] 3. Shoulder;

[0029] 31. Pressure side shoulder;

[0030] 32. Suction side shoulder;

[0031] 4. Groove;

[0032] 40. Cooling hole;

[0033] 5. Leading edge;

[0034] 6. Trailing edge;

[0035] 7. Casing. Detailed implementation manners

[0036] To make the purpose, technical solutions and advantages of the present disclosure clearer and more understandable, the following further elaborates on the present disclosure in detail with reference to specific embodiments and the accompanying drawings. The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure.

[0037] The terms "including", "comprising", etc. used herein indicate the existence of the described features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components. All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0038] In this article, unless otherwise specifically stated, directional terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to represent the orientation or positional relationship based on the orientation shown in the drawings, and are only for the convenience of describing the present disclosure, rather than indicating or implying that the device, element or component must have a specific orientation, be constructed or operated in a specific orientation. It should be understood that when the absolute position of the described object changes, the relative positional relationship they represent may also change accordingly. Therefore, these directional terms should not be construed as limiting the present disclosure.

[0039] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc. In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.

[0040] Figure 1 is a three-dimensional structure diagram of a blade for a gas turbine provided by the present invention.

[0041] Figure 2 is Figure 1 a schematic plan view at the blade tip in the illustrated embodiment.

[0042] Figure 3 is Figure 1 a three-dimensional streamline diagram of the blade tip in the illustrated exemplary embodiment.

[0043] An exemplary embodiment of the present disclosure provides a blade for a gas turbine, as Figures 1 to 3 shown. One end of the blade connected to the turbine of the gas turbine is the blade root 1, and the end away from the blade root 1 is the blade tip 2. A circumferentially extending shoulder 3 is provided at the edge of the blade tip 2, and the shoulder 3 and the blade tip 2 enclose a groove 4. Among them, the shoulder 3 includes a pressure-side shoulder 31 extending from the pressure side of the blade and a suction-side shoulder 32 extending from the suction side of the blade; a plurality of cooling holes 40 are formed on the bottom wall of the groove 4 for outputting a cooling working medium to cool the blade tip 2; the top width of the suction-side shoulder 32 is smaller than the bottom width of the suction-side shoulder 32, so that when the blade rotates with the turbine of the gas turbine, the cooling working medium flows from the cooling holes 40 to the top of the suction-side shoulder 32.

[0044] According to an embodiment of the present disclosure, Figure 3 shows a three-dimensional streamline diagram of the cooling working medium at the blade tip when the blade rotates with the turbine of the gas turbine.

[0045] In such an embodiment, the cooling working fluid is ejected from the cooling holes 40 to cool the bottom of the groove 4; as the blade rotates, the cooling working fluid gradually flows towards the suction side shoulder 32 and detaches from the blade after passing over the top of the suction side shoulder 32. Since the width of the top of the suction side shoulder 32 is smaller than the width of the bottom, the inner wall of the suction side shoulder 32 slopes outward gradually from the bottom to the top, and the flow path of the cooling working fluid is closer to the transitional shape of the inner side of the suction side shoulder 32 from the bottom to the top, enabling the cooling working fluid to flow more smoothly during the process of flowing from the bottom of the groove 4 to the top of the suction side shoulder 32, alleviating the phenomenon that the cooling working fluid stagnates at the connection between the bottom wall of the groove 4 and the inner wall of the suction side shoulder 32 to form a dead zone, and effectively improving the cooling efficiency of the top of the suction side shoulder 32; in addition, since the width of the bottom of the suction side shoulder 32 is larger, the area of the bottom wall of the groove 4 is correspondingly reduced, facilitating the cooling of the groove 4.

[0046] In an exemplary embodiment, the width of the top of the pressure side shoulder 31 is smaller than the width of the bottom of the pressure side shoulder 31, which also alleviates the phenomenon that the cooling working fluid stagnates at the connection between the bottom wall of the groove 4 and the inner wall of the pressure side shoulder 31, facilitating the flow of the cooling working fluid driven by the gas flow and improving the cooling efficiency to a certain extent.

[0047] Figure 4 is Figure 2 The schematic cross-sectional view at A-A in the [description].

[0048] According to an embodiment of the present disclosure, as Figure 4 shown, the inner walls of the pressure side shoulder 31 and the suction side shoulder 32 form an inclination angle a with the vertical direction, and 0° < a < 90°.

[0049] In such an embodiment, the inner walls of the pressure side shoulder 31 and the suction side shoulder 32 are configured as inclined walls. More specifically, the inclination angle a satisfies 10° < a < 45°, that is, the angle between the inclined wall and the bottom wall of the groove 4 is 100° - 135°. When 0° < a < 10°, a relatively obvious stagnation phenomenon still occurs at the junction between the inclined wall and the bottom wall of the groove 4 for the cooling working fluid, and the cooling effect is not ideal; when 45° < a < 90°, during cooling, the bottom wall of the groove 4 is cooled by the gas film formed by the cooling working fluid on the bottom wall surface, and the inclined wall is cooled by the cooling working fluid during the migration process. However, if the inclination angle a is too large, the area of the bottom wall will be reduced and the area of the inclined wall will become larger, resulting in too fast a flow rate of the cooling working fluid, and a larger inclined wall area requires more cooling working fluid to flow through for cooling, which is not conducive to improving the cooling efficiency.

[0050] Figure 5 is the schematic cross-sectional view at A-A of another embodiment provided by the present invention.

[0051] In an exemplary embodiment, as Figure 5 shown, the inner walls of the pressure-side shoulder 31 and the suction-side shoulder 32 are configured as arc-shaped walls that are recessed toward the shoulder 3, and the secant line of the arc-shaped wall forms an angle b with the vertical direction, and 0° < a < 90° is satisfied.

[0052] In such an embodiment, the inner walls of both the pressure-side shoulder 31 and the suction-side shoulder 32 are configured as arc-shaped walls that are recessed toward the shoulder 3, and the secant line of the arc-shaped wall forms an angle of 0° - 90° with the vertical direction. The arc-shaped wall configured in this way can more favorably allow the cooling working fluid at the groove 4 to flow toward the top of the shoulder 3, so as to improve the cooling effect at the top of the shoulder 3.

[0053] In some other embodiments, the arc-shaped wall can also be configured to protrude away from the shoulder 3. However, it should be noted that the angle formed by the secant line of the arc-shaped wall protruding away from the shoulder 3 with the vertical direction is preferably greater than the angle b, and the radian of the arc-shaped wall should not be too small, preferably greater than or equal to 0.5 rad.

[0054] In an exemplary embodiment, the outer wall of the shoulder 3 is flush with the outer surface of the blade.

[0055] Specifically, the outer wall of the pressure-side shoulder 31 is flush with the outer surface of the blade to reduce the influence caused by the pressure-side lateral force; the outer wall of the suction-side shoulder 32 is flush with the outer surface of the blade to reduce the influence caused by the suction-side lateral force, which can improve the strength and stiffness at the connection between the shoulder 3 and the blade tip 2 and prevent damage or fracture.

[0056] In an exemplary embodiment, the blade rotates along a preset direction with the turbine of the gas turbine; the depth of the groove 4 is H, the height of the pressure-side shoulder 31 is h, and 0 ≤ h ≤ H is satisfied. The height of the suction-side shoulder 32 is equal to the depth of the groove 4.

[0057] In such an embodiment, the height of the pressure-side shoulder 31 can be equal to the depth of the groove 4 to improve the overall stiffness and strength of the blade; the height of the pressure-side shoulder 31 can also be less than the depth of the groove 4, a part of the pressure-side shoulder 31 can be removed, or the pressure-side shoulder 31 can be not provided. Configured in this way can reduce the resistance suffered by the blade during rotation, reduce leakage loss, improve work efficiency, and extend service life.

[0058] In an exemplary embodiment, the top width of the shoulder 3 is w, the diameter of the cooling hole 40 is D, the chord length of the blade is L, 0.01L ≤ w ≤ 0.04L, 0.005L ≤ D ≤ 0.01L.

[0059] In an exemplary embodiment, one end of the blade near the gas inlet is the leading edge 5, and one end near the gas outlet is the trailing edge 6. The width of the shoulder 3 at the leading edge 5 is greater than the width of the shoulder 3 at the trailing edge 6.

[0060] In such an embodiment, since the leading edge 5 of the blade bears a greater pressure, setting the width of the shoulder 3 at the leading edge 5 to be greater than the width of the shoulder 3 at the trailing edge 6 can improve the strength and stiffness of the shoulder 3 at this location; affected by the shape of the blade, in order to reduce the mass and moment of inertia of the blade, the width of the shoulder 3 at the trailing edge 6 is usually less than or even smaller than the width of the shoulder 3 at the leading edge 5 to facilitate the rotation of the blade.

[0061] In an exemplary embodiment, the depth of the groove 4 is H, the chord length of the blade is L, and 0.01L ≤ H ≤ 0.04L.

[0062] In a schematic embodiment, the diameter D of the cooling hole 40 is 1 mm, the depth H of the groove 4 is 2.1 mm, the inclination angle a is 30°, the width of the shoulder 3 at the leading edge 5 is 2.4 mm, the width of the shoulder 3 at the trailing edge 6 is 1.8 mm, and the chord length L of the blade is 150 mm.

[0063] Figure 6 It is a comparison chart of the average cooling efficiency at the top of the suction side shoulder of the prior art and the embodiments provided by the present invention.

[0064] According to an embodiment of the present disclosure, Figure 6 It shows a comparison chart of the cooling efficiency at the top of the suction side shoulder 32 of the prior art and the embodiments provided by the present invention at four blowing ratios of 0.5, 1.0, 1.5, and 2.0 (the density ratio of the jet to the mainstream, that is, the product of the density of the mainstream or the jet and the corresponding velocity). The results show that the blade structure in the embodiments provided by the present invention can effectively improve the cooling efficiency at the top of the suction side shoulder 32.

[0065] The present invention also provides a gas turbine, including a compressor, a combustion chamber, and a turbine. Among them, the compressor is used to compress air; the combustion chamber can receive the compressed air from the compressor, mix the compressed air with fuel, and ignite it to generate gas; the blades in any of the above embodiments are installed on the turbine, and the gas generated by the combustion chamber impacts the blades to drive the turbine to rotate, so as to convert the energy contained in the gas into turbine kinetic energy and output it externally.

[0066] According to an embodiment of the present disclosure, the gas turbine further includes a casing 7 for supporting and protecting the compressor, the combustion chamber, and the turbine, as Figure 4 and Figure 5As shown, the distance between the casing 7 and the top of the shoulder 3 is the tip clearance C, and the size of the tip clearance C is 1%-2% of the blade chord length L. When the tip clearance C is too large, the leakage flow generated when the gas flows through the blade tip 2 will increase, resulting in a decrease in the gas work efficiency and a loss of the turbine mechanical energy. When the tip clearance C is too small, vortices and separations will be generated when the gas flows through the blade tip 2, the work efficiency will decrease, and the friction between the gas and the blade tip 2 will increase, which will not only lead to a loss of the turbine mechanical energy, but also cause additional wear to the blade tip 2, shortening the working life.

[0067] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recited in the various embodiments and / or claims of the present disclosure can be combined and combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0068] The embodiments of the present disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments have been described separately above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A blade for a gas turbine, one end of the blade connected to the turbine of the gas turbine is the blade root (1), and the end far from the blade root (1) is the blade tip (2). Characterized in that, a circumferentially extending shoulder (3) is provided at the edge of the blade tip (2), and the shoulder (3) and the blade tip (2) enclose a groove (4); the shoulder (3) includes a pressure-side shoulder (31) extending from the pressure side of the blade and a suction-side shoulder (32) extending from the suction side of the blade; cooling holes (40) are formed on the bottom wall of the groove (4), suitable for outputting a cooling working medium to cool the blade tip (2); the width of the top of the suction-side shoulder (32) is smaller than the width of the bottom of the suction-side shoulder (32), so as to facilitate the cooling working medium to flow from the cooling holes (40) to the top of the suction-side shoulder (32) during the rotation of the blade with the turbine of the gas turbine.

2. The blade according to claim 1, Characterized in that, the width of the top of the pressure-side shoulder (31) is smaller than the width of the bottom of the pressure-side shoulder (31).

3. The blade according to claim 2, Characterized in that, the inner side walls of the pressure-side shoulder (31) and the suction-side shoulder (32) form an inclination angle a with the vertical direction, and 0° < a < 90°.

4. The blade according to claim 2, Characterized in that, the inner side walls of the pressure-side shoulder (31) and the suction-side shoulder (32) are configured as arc-shaped walls recessed towards the shoulder (3), and the secant line of the arc-shaped wall forms an angle b with the vertical direction, and 0° < b < 90°.

5. The blade according to any one of claims 1-4, Characterized in that, the outer side wall of the shoulder (3) is flush with the outer surface of the blade.

6. The blade according to any one of claims 1-4, Characterized in that, the blade rotates with the turbine of the gas turbine along a preset direction; the depth of the groove (4) is H, the height of the pressure-side shoulder (31) is h, and 0 ≤ h ≤ H, and the height of the suction-side shoulder (32) is equal to the depth of the groove (4).

7. The blade according to any one of claims 1-4, Characterized in that, the top width of the shoulder (3) is w, the diameter of the cooling hole (40) is D, and the chord length of the blade is L, 0.01L ≤ w ≤ 0.04L, 0.005L ≤ D ≤ 0.01L.

8. The blade according to any one of claims 1-4, Characterized in that, one end of the blade close to the gas inlet is the leading edge (5), and one end close to the gas outlet is the trailing edge (6); the width of the shoulder (3) at the leading edge (5) is greater than the width of the shoulder (3) at the trailing edge (6).

9. The blade according to any one of claims 1-4, Characterized in that, the depth of the groove (4) is H, and the chord length of the blade is L, 0.01L ≤ H ≤ 0.04L.

10. A gas turbine, comprising: a compressor, suitable for compressing air; A combustion chamber capable of mixing fuel with compressed air and igniting the mixture to generate combustion gas; and a turbine equipped with the blade according to any one of claims 1-9, wherein the impact of the combustion gas on the blade drives the turbine to rotate, so as to convert the energy of the combustion gas into the kinetic energy of the turbine.

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