CN118548121A - Blade with blade tip cooling function and turbine - Google Patents

Abstract

The invention provides a blade with a blade top cooling function and a turbine, and relates to the technical field of cooling of turbine blades of gas turbines, comprising a blade body part, a cover plate part and a shoulder part, wherein the blade body part is provided with a cooling working medium flow passage, and the inner wall surface of the cooling working medium flow passage is provided with a first concave part which is concave towards at least one of a pressure surface and a suction surface of the blade body part; the cover plate part is arranged on the top surface of the blade body part so as to cover the top surface of the cooling working medium flow passage; the outer periphery of the top surface of the cover plate part is provided with the shoulder part, and the shoulder part and the cover plate part enclose a groove; the blade is provided with a first air film hole extending in a direction from the top surface of the shoulder portion toward the blade body portion and extending to the wall surface of the first recess portion. The invention can directly form the gas film hole on the shoulder of the blade so as to cool the shoulder and effectively prevent gas leakage loss.

Description

Blades and turbines with tip cooling

Technical Field

The present invention relates to the technical field of gas turbine blade cooling, and in particular to a blade and a turbine with blade tip cooling function.

Background Art

Gas turbines usually operate under high-temperature combustion gas, especially the first-stage and second-stage moving blades in the turbine. The moving blades, as rotating parts, form a gap between them and the stationary guard rings above them. In order to ensure the operating efficiency of the gas turbine, the first two stages of moving blades are often arranged with shoulder structures to reduce the leakage of combustion gas through the blade tips.

The shoulder structure of the moving blade tip is operated under high-temperature combustion gas. In the related technology, the blade tips of some existing gas turbines' first-stage moving blades and second-stage moving blades are provided with air film holes in the grooves formed by the shoulder, as shown in FIG1, so that cold air can cover the shoulder through the air film to achieve the purpose of cooling the shoulder. However, since the flow of combustion gas on the moving blade tip is extremely complex, it is difficult to form a good air film coverage on the shoulder, so that the shoulder often overheats and ablates, thereby causing more combustion gas leakage and reducing the working efficiency of the gas turbine.

Summary of the invention

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

To this end, an embodiment of one aspect of the present invention proposes a blade with a blade tip cooling function, which can directly form air film holes on the boss of the blade to cool the boss and effectively prevent gas leakage losses.

According to another aspect of the present invention, a turbine is provided.

According to an embodiment of the present invention, a blade with a blade tip cooling function comprises a blade body, a cover plate and a shoulder portion, the blade body portion having a cooling fluid flow channel, the inner wall surface of the cooling fluid flow channel having a first recessed portion that is recessed toward at least one of the pressure surface and the suction surface of the blade body portion; the cover plate portion is arranged on the top surface of the blade body portion to seal the top surface of the cooling fluid flow channel; the shoulder portion is arranged on the outer peripheral edge of the top surface of the cover plate portion, and the shoulder portion and the cover plate portion form a groove; the blade is provided with a first air film hole, and the first air film hole extends in a direction from the top surface of the shoulder portion toward the blade body portion and extends to the wall surface of the first recessed portion.

According to the blade with blade tip cooling function of the embodiment of the present invention, the first recessed portion formed on the inner wall surface of the cooling medium flow channel and the top surface of the boss portion cooperate to construct a processing condition for directly processing the first air film hole on the boss portion by conventional process means on the blade, thereby reducing the process difficulty of directly forming the first air film hole on the boss portion. The first air film hole allows the cooling medium in the cooling medium flow channel to flow out along the first air film hole to the top surface of the boss to achieve cooling of the boss itself. Therefore, compared with the related art, the present invention can directly form an air film hole on the boss of the blade to cool the boss and effectively prevent gas leakage losses.

In some embodiments, the designed wall thickness of the blade body at the position having the first recess is defined as b ₁ , the designed wall thickness being the wall thickness of the blade body without the first recess, and the depth t ₁ of the first recess satisfies: 0<3t ₁ ≤b ₁ .

In some embodiments, the aperture of the first air film hole is D, the thickness of the convex shoulder portion is B, and 0＜D≤0.5B.

In some embodiments, there are multiple first air film holes, and the multiple first air film holes include at least one row of first air film holes arranged at intervals along the thickness direction of the boss portion, and each row of first air film holes includes at least two first air film holes arranged at intervals along the length direction of the boss portion.

In some embodiments, a second recessed portion that is recessed toward a top surface of the cover portion is disposed on the bottom surface of the cover portion, and the second recessed portion is directly connected to the first recessed portion.

In some embodiments, the thickness direction of the cover plate portion is consistent with the height direction of the blade body portion, and the design thickness of the cover plate portion at the position having the second recess is defined as b ₂ , the design thickness is the thickness of the cover plate portion when the second recess is not provided, and the depth t ₂ of the second recess satisfies: 0＜t ₂ ≤0.5b ₂ .

In some embodiments, the blade with blade tip cooling function also includes a second air film hole, which extends from the top surface of the cover plate portion toward the bottom surface of the cover plate portion, and extends to the bottom surface of the cover plate portion to communicate with the cooling medium flow channel.

In some embodiments, a protrusion is further provided on the bottom surface of the cover plate portion, and the second air film hole extends from the top surface of the cover plate portion toward the bottom surface of the cover plate portion and extends to the side of the protrusion away from the cover plate.

In some embodiments, there are multiple second air film holes, and the multiple second air film holes include multiple columns of second air film holes arranged at intervals along the thickness direction of the blade body, and each column of second air film holes includes at least two second air film holes arranged at intervals along the length direction of the blade body. There are multiple protrusions, and the multiple protrusions correspond one-to-one to the multiple second air film holes, or each column of second air film holes corresponds to one protrusion.

In some embodiments, the outer contour of the protrusion may be one of a circle, a polygon, and any closed curve.

A turbine according to an embodiment of the present invention includes a guard ring and a blade, wherein the blade is the blade described in any of the above embodiments, the boss portion of the blade is spaced apart from the guard ring in the height direction of the blade, the guard ring, the top surface of the boss portion and the groove of the blade define a blade top gas flow channel, and the first air film hole of the blade is connected to the blade top gas flow channel.

According to the turbine of the embodiment of the present invention, the blade is designed to be formed with a first air film hole on the shoulder portion, so that the cooling medium in the cooling medium flow channel can flow out along the first air film hole to the top surface of the shoulder portion, thereby realizing direct cooling of the shoulder portion, avoiding the problem of overheating and ablation of the shoulder portion due to operation under high-temperature fuel gas, and effectively preventing fuel gas leakage loss. Therefore, compared with related technologies, the turbine using this blade can ensure the working efficiency of the gas turbine.

Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the connection structure between blades and guard rings in the prior art.

FIG. 2 is a schematic structural diagram of a blade with a blade tip cooling function according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of the connection structure between the blade and the guard ring in FIG. 2 .

FIG. 4 is another schematic diagram of the structure of a blade with a blade tip cooling function according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of the connection structure between the blade and the guard ring in FIG. 4 .

Figure numerals: 1. blade body, 11. cooling medium flow channel, 12. pressure surface, 13. suction surface, 2. cover plate portion, 3. shoulder portion, 4. first recess, 5. first air film hole, 6. second recess, 7. second air film hole, 8. protrusion, 9. guard ring, 91. blade tip gas flow channel.

DETAILED DESCRIPTION

Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

As shown in FIG. 2 and FIG. 4 , a blade with a tip cooling function according to an embodiment of the present invention includes a blade body portion 1 , a cover plate portion 2 and a shoulder portion 3 .

Among them, the blade body 1 has a cooling fluid flow channel 11, and the inner wall surface of the cooling fluid flow channel 11 has a first recess 4 that is recessed toward at least one of the pressure surface 12 and the suction surface 13 of the blade body 1. The inner wall surface of the cooling fluid flow channel 11 is the inner wall surface of the blade body 1 used to surround the cooling fluid flow channel 11.

The cover plate portion 2 is disposed on the top surface of the blade body portion 1 to cover the top surface of the cooling medium flow channel 11 .

A convex shoulder portion 3 is provided on the outer periphery of the top surface of the cover plate portion 2 , and the convex shoulder portion 3 and the cover plate portion 2 form a groove.

The blade is provided with a first air film hole 5, which extends from the top surface of the convex shoulder portion 3 toward the blade body 1 and extends to the wall surface of the first recess 4, wherein the wall surface of the first recess 4 is the inner wall surface of the cooling medium flow channel 11 used to surround the wall surface of the first recess 4, and the first air film hole 5 connects the cooling medium flow channel 11 with the outside through the convex shoulder portion 3.

According to the blade with blade tip cooling function of the embodiment of the present invention, the first recessed portion 4 formed on the inner wall surface of the cooling medium flow channel 11 and the top surface of the boss portion 3 cooperate to construct a processing condition in which the first air film hole 5 can be directly processed on the boss portion 3 by conventional process means on the blade, thereby reducing the process difficulty of directly forming the first air film hole 5 on the boss portion 3. The first air film hole 5 allows the cooling medium in the cooling medium flow channel 11 to flow out along the first air film hole 5 to the top surface of the boss to achieve cooling of the boss itself. Therefore, compared with the related art, the present invention can directly form an air film hole on the boss of the blade to cool the boss and effectively prevent gas leakage losses.

It can be understood that the inner wall surface of the cooling medium flow channel 11 includes a first wall surface adjacent to the pressure surface 12 of the blade body 1 and a second wall surface adjacent to the suction surface 13 of the blade body 1. In some embodiments of the present invention, the first wall surface has a first recessed portion 4 recessed toward the pressure surface 12 of the blade body 1; in other embodiments, the second wall surface has a first recessed portion 4 recessed toward the suction surface 13 of the blade body 1; in still other embodiments, the first wall surface has a first recessed portion 4 recessed toward the pressure surface 12 of the blade body 1, and the second wall surface has a first recessed portion 4 recessed toward the suction surface 13. Therefore, in the blade with blade tip cooling function of the present invention, the structure of the first recessed portion 4 can be the above three structures respectively.

It should be noted that the bosses in the related art either have no air film cooling hole structure or have air film cooling holes, but the height of the bosses is very short, otherwise the air film holes cannot be opened. The structural design of the first recess 4 adopted in the present invention can meet the requirements of arranging air film holes in the case of high bosses and effectively cool the high boss structure. The advantages of the high boss structure over the low boss structure are: ① The high boss is better at preventing gas leakage losses; ② The high boss is more wear-resistant than the low boss to protect the blade body 1.

As shown in FIG. 2 and FIG. 4 , in some embodiments, the designed wall thickness of the blade body 1 at the position having the first recess 4 is defined as b ₁ , and the designed wall thickness is the wall thickness of the blade body 1 when the first recess 4 is not provided. The depth t ₁ of the first recess 4 satisfies: 0＜3t ₁ ≤b ₁ , that is, the depression depth of the first recess 4 in the direction of the pressure surface 12 (or the suction surface 13) of the blade body 1 does not exceed one third of the wall thickness of the blade body 1 at the position where the first recess 4 is provided. Designing the depth t ₁ of the first recess 4 within this range can not only facilitate the provision of the first air film hole 5, but also avoid the problem that the first recess 4 is too deeply depressed, which affects the blade strength and is prone to cracks.

It is understandable that the specific depth of the first recess 4 can also be designed according to the blade specifications and structural strength, the height of the shoulder 3, and the cooling effect of the shoulder 3, which will not be elaborated here. At the same time, the opening of the first recess 4 can also reduce the wall thickness at the corresponding position of the blade body 1 to reduce the thermal resistance of the heat conduction, so that the shoulder 3 can be cooled more effectively.

As shown in Figures 2 and 4, in some embodiments, the aperture of the first air film hole 5 is D, the thickness of the boss portion 3 is B, 0＜D≤0.5B, that is, the aperture of the first air film hole 5 does not exceed half of the thickness of the boss portion 3. Designing the aperture of the first air film hole 5 within this range can facilitate the opening of the first air film hole 5 and avoid the problem of too large aperture, which affects the strength of the boss portion and is prone to cracks.

It is understandable that, since the shoulder portion 3 is an annular structure (the annular structure follows the blade shape of the blade body portion 1 ), its thickness can be defined. The thickness direction of the shoulder portion 3 can be consistent with the thickness direction of the blade body portion 1 .

Specifically, the thickness direction of the shoulder portion 3 and the thickness direction of the blade body portion 1 may be the left-right direction in FIG. 2 .

As shown in Figures 2 and 4, in some embodiments, there are multiple first air film holes 5, and the multiple first air film holes 5 include at least one row of first air film holes 5 arranged at intervals along the thickness direction of the boss portion 3, and each row of first air film holes 5 includes at least two first air film holes 5 arranged at intervals along the length direction of the boss portion 3.

It is understandable that the thickness of the shoulder portion 3 is generally not too thick, so a row of first air film holes 5 can be arranged in the thickness direction of the shoulder portion 3 to further simplify the processing technology of the first air film holes 5 and save costs while ensuring the cooling effect of the first air film holes 5 on the shoulder portion 3. The length direction of the shoulder portion 3 is the length direction of the blade body 1, that is, the direction from the leading edge to the trailing edge of the blade.

Specifically, the first recess 4 may extend along the length direction of the blade body 1, and the first recess 4 corresponds to at least one row of first air film holes 5; or, there may be multiple first recesses 4 which are arranged at intervals along the length direction of the blade body 1, and the multiple first recesses 4 correspond one-to-one to the multiple first air film holes 5.

As shown in Figures 2 and 4, in some embodiments, the bottom surface of the cover portion 2 is provided with a second recess 6 recessed toward the top surface of the cover portion 2, and the second recess 6 is directly connected to the first recess 4, that is, the wall surface of the first recess 4 is directly connected to the wall surface of the second recess 6, forming an integral recess structure, so as to facilitate the formation of the first air film hole 5 connected to the cooling medium flow channel 11 on the boss portion 3.

As shown in Figures 2 and 4, in some embodiments, there are multiple second recesses 6, and the multiple second recesses 6 are arranged at intervals along the thickness direction of the blade body portion 1 (i.e., the width direction of the cover plate portion 2), wherein, among the second recesses 6 adjacent to the pressure surface 12 of the blade body portion 1, the second recess 6 closest to the first recess 4 recessed toward the pressure surface 12 of the blade body portion 1 is connected to the corresponding first recess 4, that is, the walls of the two are directly connected, and among the second recesses 6 adjacent to the suction surface 13 of the blade body portion 1, the second recess 6 closest to the first recess 4 recessed toward the suction surface 13 of the blade body portion 1 is connected to the corresponding first recess 4, that is, the walls of the two are directly connected.

It can be understood that the multiple second recesses 6 opened on the bottom surface of the cover portion 2 can also enhance the disturbance of the cooling medium (i.e., the cooling fluid) on the bottom surface of the cover portion 2, thereby enhancing the heat exchange between the cooling medium and the wall surface, and the recessed structure also increases the heat exchange area, further improving the ability of the cooling medium to take away the heat from the wall surface.

As shown in FIG. 2 and FIG. 4 , in some embodiments, the thickness direction of the cover plate portion 2 is consistent with the height direction of the blade body portion 1 , and the design thickness of the cover plate portion 2 at the position having the second recess 6 is defined as b ₂ , and the design thickness is the thickness of the cover plate portion 2 when the second recess 6 is not provided. The depth t ₂ of the second recess 6 satisfies: 0＜t ₂ ≤0.5b ₂ , that is, the depression depth of the second recess 6 in the height direction of the shoulder does not exceed one half of the thickness of the cover plate portion 2 at the position where the second recess 6 is provided. By designing the depth t ₂ of the second recess 6 within this range, it is possible to avoid the problem of too deep depression, which may affect the strength of the cover plate portion 2 and easily cause cracks.

Similarly, it can be understood that the specific depth of the second recess 6 can be designed according to the blade specifications and structural strength, the height of the cover plate 2, and the cooling effect on the shoulder 3, etc., and will not be elaborated in detail here. At the same time, the opening of the second recess 6 can also reduce the wall thickness of the corresponding position of the cover plate 2 to reduce the thermal resistance of the heat conduction, which is conducive to cooling the cover plate 2.

Specifically, the thickness direction of the cover plate portion 2 , the height direction of the blade body portion 1 , and the height direction of the shoulder may be the up-and-down direction in FIG. 3 .

As shown in FIG. 2 and FIG. 4 , in some embodiments, the blade with blade tip cooling function further includes a second air film hole 7, which extends from the top surface of the cover plate portion 2 toward the bottom surface of the cover plate portion 2, and extends to the bottom surface of the cover plate portion 2 to communicate with the cooling medium flow channel 11, thereby arranging air film holes leading to the groove surrounded by the shoulder portion 3 and the cover plate portion 2 to cool the cover plate. The second air film hole 7 connects the cooling medium flow channel 11 with the outside.

As shown in Figures 2 and 4, in some embodiments, a protrusion 8 is further provided on the bottom surface of the cover portion 2, and the second air film hole 7 extends from the top surface of the cover portion 2 toward the bottom surface of the cover portion 2 and extends to the side of the protrusion 8 away from the cover plate, that is, the second air film hole 7 passes through the protrusion 8 and is connected with the cooling medium flow channel 11.

It can be understood that the bottom surface of the cover portion 2 can enhance the disturbance of the cooling medium (i.e., the cooling fluid) on the bottom surface of the cover portion 2, thereby enhancing the heat exchange between the cooling medium and the wall surface, and the protrusion 8 structure also increases the heat exchange area, further improving the ability of the cooling medium to take away the heat from the wall surface. At the same time, due to the presence of the protrusion 8, the length of the second air film hole 7 is also increased, the heat taken away by the cold air is increased, and the cooling effect is better.

It should be noted that the heat exchange amount Q = h*A*ΔT, where h is the heat exchange coefficient, A is the heat exchange area, and ΔT is the temperature difference between the wall temperature and the cold air. As the length of the second air film hole 7 increases, the heat exchange area increases, so the heat taken away by the cold air increases. The protrusion 8 increases the thickness of the cover plate 2, and the second recess 6 thins the cover plate 2. At the same time, the protrusion 8 is combined with the second air film hole 7 to achieve cooling, and the protrusion 8 structure is in the middle part of the cover plate 2. Generally, the cover plate 2 is thinner as a whole. Therefore, the overall effect is conducive to cooling the cover plate 2.

As shown in Figures 2 and 4, in some embodiments, there are multiple second air film holes 7, the multiple second air film holes 7 include multiple columns of second air film holes 7 arranged at intervals along the thickness direction of the blade body 1, each column of second air film holes 7 includes at least two second air film holes 7 arranged at intervals along the length direction of the blade body 1, there are multiple protrusions 8, the multiple protrusions 8 correspond one-to-one to the multiple second air film holes 7, or, each column of second air film holes 7 corresponds to one protrusion 8, and in this case, the protrusion 8 extends along the length direction of the blade body 1.

It should be noted that when there are multiple protrusions 8, a groove will be formed on the bottom surface of the cover portion 2 between any two adjacent protrusions 8, and the groove and the multiple second recesses 6 located in the middle part of the cover portion 2 are not an integrated structure on the cover portion 2, that is, the groove and the second recess 6 are two different recessed structures formed on the cover portion 2.

As shown in FIG. 2 and FIG. 4 , in some embodiments, the outer contour of the protrusion 8 may be one of a circle, a polygon and any closed curve.

As shown in Figures 3 and 5, a turbine according to an embodiment of the present invention includes a guard ring 9 and blades, wherein the blades are blades of any of the above embodiments, and the boss portion 3 of the blade is spaced apart from the guard ring 9 in the height direction of the blade, and a blade top gas flow channel 91 is defined between the guard ring 9, the top surface of the boss portion 3 and the groove of the blade, and the first air film hole 5 of the blade is connected to the blade top gas flow channel 91, wherein the height direction of the blade can be the up and down direction in the figure.

According to the turbine of the embodiment of the present invention, the blade is designed to be formed with a first air film hole 5 on the shoulder portion 3, so that the cooling medium in the cooling medium flow channel 11 can flow out along the first air film hole 5 to the top surface of the shoulder portion 3, thereby realizing direct cooling of the shoulder portion 3, avoiding the problem of overheating and ablation of the shoulder portion 3 due to operation under high-temperature fuel gas, and effectively preventing fuel gas leakage loss. Therefore, compared with related technologies, the turbine using this blade can ensure the working efficiency of the gas turbine.

In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims (10)

1. A blade having a tip cooling function, comprising:

A blade body portion having a cooling medium flow passage, an inner wall surface of the cooling medium flow passage having a first concave portion concave toward at least one of a pressure surface and a suction surface of the blade body portion;

The cover plate part is arranged on the top surface of the blade body part so as to cover the top surface of the cooling working medium flow passage; and

The outer periphery of the top surface of the cover plate part is provided with the shoulder part, and the shoulder part and the cover plate part enclose a groove;

The blade is provided with a first air film hole extending in a direction from the top surface of the shoulder portion toward the blade body portion and extending to the wall surface of the first recess portion.

2. The blade with a tip cooling function according to claim 1, wherein a design wall thickness of the blade body portion at a position having the first concave portion is defined as b ₁, the design wall thickness being a wall thickness when the blade body portion is not provided with the first concave portion, a depth t ₁ of the first concave portion satisfying: 0 < 3t ₁≤b₁.

3. The blade with a tip cooling function according to claim 1 or 2, wherein the aperture of the first film hole is D, and the thickness of the shoulder portion is B,0 < D is less than or equal to 0.5B;

And/or the plurality of first air film holes are arranged, the plurality of first air film holes comprise a plurality of rows of first air film holes which are arranged at intervals along the thickness direction of the shoulder part, and each row of first air film holes comprise at least two first air film holes which are arranged at intervals along the length direction of the shoulder part.

4. The blade with a tip cooling function according to claim 1, wherein a bottom surface of the cover plate portion is provided with a second recess recessed toward a top surface of the cover plate portion, the second recess and the first recess being in direct communication.

5. The blade with a tip cooling function according to claim 4, wherein a thickness direction of the cover plate portion coincides with a height direction of the blade body portion, a design thickness of the cover plate portion at a position having the second concave portion is defined as b ₂, the design thickness being a thickness when the cover plate portion is not provided with the second concave portion, and a depth t ₂ of the second concave portion satisfies: 0 < t ₂≤0.5b₂.

6. The blade with a tip cooling function according to claim 4 or 5, further comprising a second film hole extending in a direction from a top surface of the cover plate portion toward a bottom surface of the cover plate portion and extending to the bottom surface of the cover plate portion to communicate with the cooling medium flow passage.

7. The blade with a tip cooling function according to claim 6, wherein the bottom surface of the cover plate portion is further provided with a protrusion, and the second film hole extends from the top surface of the cover plate portion toward the bottom surface of the cover plate portion and to a side surface of the protrusion away from the cover plate.

8. The blade with a blade tip cooling function according to claim 7, wherein the second air film holes are multiple, the second air film holes comprise at least one row of second air film holes which are arranged at intervals along the thickness direction of the blade body part, each row of second air film holes comprise at least two second air film holes which are arranged at intervals along the length direction of the blade body part, the protrusions are multiple, the protrusions are in one-to-one correspondence with the second air film holes, or each row of second air film holes is in one-to-one correspondence with one protrusion.

9. The blade with tip cooling function according to claim 8, wherein the convex outer profile may be one of circular, polygonal and arbitrary closed curves.

10. A turbine, comprising:

A guard ring; and

A vane, wherein the vane is as claimed in any one of claims 1 to 9, the shoulder of the vane is spaced apart from the shroud in the height direction of the vane, a tip gas flow passage is defined between the shroud, the top surface of the shoulder and the recess of the vane, and the first gas film hole of the vane is communicated with the tip gas flow passage.