Novel air film hole with communicating groove and turbine blade

Abstract

The invention provides a novel air film hole with a communicating groove and a turbine blade, the novel air film hole with the communicating groove comprises a first cylindrical hole structure, a second cylindrical hole structure and a communicating groove structure, and the first cylindrical hole structure and the second cylindrical hole structure are the same in structure; the first cylindrical hole structure and the second cylindrical hole structure are symmetrically distributed relative to the center line of the communicating groove structure, and the two ends of the communicating groove structure are connected with one end of the first cylindrical hole structure and one end of the second cylindrical hole structure correspondingly. The other end of the first cylindrical hole structure and the other end of the second cylindrical hole structure extend in the direction close to the center line of the communicating groove structure. According to the blade, the outflow amount of cold air can be effectively reduced, the cold air covering area and the cold air covering uniformity of the air film holes are increased, the problem that cold air is blown away from the wall surface under the high blowing ratio is effectively solved, the cooling efficiency of the blade surface is improved, and the risk that high-temperature fuel gas ablates the blade is prevented.

Description

Technical Field

[0001] The invention relates to the technical field of cooling of gas turbine blades, and in particular to a novel air film hole with a connecting groove and a turbine blade. Background Art

[0002] In order to meet the requirements of high-performance gas turbines, the turbine inlet temperature continues to rise, resulting in a significant increase in the thermal load of the turbine blades. As a cooling technology widely used in turbine blades, film cooling can effectively isolate the invasion of high-temperature combustion gas and prevent blade ablation. Initially, due to the low processing difficulty, discrete cylindrical film hole structures were mainly used on turbine blades. However, cylindrical holes have problems such as small spanwise coverage and excessive concentration of cold air momentum, making it difficult to form uniform and efficient cold air coverage on the blade surface. Especially under large blowing ratios, the cold air outflow is very easy to blow away from the wall, which can cause cooling failure in severe cases. Therefore, traditional discrete cylindrical holes are difficult to meet the increasing cooling needs. In order to match the increase in turbine front temperature brought about by the improvement of gas turbine performance and enhance the efficiency of film cooling, researchers have developed many special-shaped film hole structures, such as contraction-expansion holes, slot holes, crescent holes, cat ear holes, fan-shaped holes, etc. However, most special-shaped film holes increase the complexity of the structure, further increasing the processing difficulty and processing cost. Therefore, cylindrical film holes are still the main film cooling elements for domestic turbine blades. Summary of the invention

[0003] In view of this, the embodiments of the present specification provide a novel air film hole and a turbine blade with a connecting groove to achieve the purpose of improving the air film cooling efficiency.

[0004] The embodiments of this specification provide the following technical solutions: a new type of air film hole with a connecting groove, comprising a first cylindrical hole structure, a second cylindrical hole structure and a connecting groove structure, the first cylindrical hole structure is identical to the second cylindrical hole structure, and the first cylindrical hole structure and the second cylindrical hole structure are symmetrically distributed relative to the center line of the connecting groove structure, the two ends of the connecting groove structure are respectively connected to one end of the first cylindrical hole structure and one end of the second cylindrical hole structure, and the other end of the first cylindrical hole structure and the other end of the second cylindrical hole structure both extend in a direction close to the center line of the connecting groove structure.

[0005] Further, in the vertical projection plane, the angle between the axis of the first cylindrical hole structure and the midline of the connecting groove structure is α, wherein 0<α≤18°.

[0006] Furthermore, the angle between the end surface of the other end of the first cylindrical hole structure and the axis of the first cylindrical hole structure is γ, wherein 30°≤γ≤55°.

[0007] Further, the axial length of the first cylindrical hole structure is L1, and the diameter of the first cylindrical hole structure is D, wherein 2.8D≤L1≤8D.

[0008] Furthermore, the connection length between the connecting groove structure and the first cylindrical hole structure at the axial position is L2, wherein 0.3L1≤L2≤0.7L1.

[0009] Furthermore, the cross-section of the connecting groove structure is a trapezoidal structure.

[0010] Furthermore, the groove width of the connecting groove structure is H, wherein 0.4D≤H≤0.8D; the upper base of the connecting groove structure is W1, wherein 3D≤W1≤5.5D; the lower base of the connecting groove structure is W2, wherein 3D≤W2≤6D, and W2>W1.

[0011] Furthermore, the included angle between the hypotenuse and the lower bottom of the connecting groove structure is β, wherein 55°≤β≤90°.

[0012] Furthermore, 0.45 mm ≤ D ≤ 1.5 mm.

[0013] The present invention also provides a turbine blade, comprising the novel air film hole with connecting groove.

[0014] Compared with the prior art, the beneficial effects achieved by at least one of the above technical solutions adopted in the embodiments of this specification include at least: effectively reducing the outflow momentum of cold air, increasing the cold air coverage area and cold air coverage uniformity of the air film holes, effectively solving the problem of cold air blowing away from the wall under high blowing ratio, improving the cooling efficiency of the blade surface, and preventing the risk of high-temperature gas ablating the blade. It can be widely used in modern gas turbines and has a positive effect on improving the performance and reliability of turbine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a schematic diagram of the novel air film hole structure with connecting grooves of the present invention;

[0017] Figure 2 This is a front view of a novel air film hole structure with a connecting groove according to the present invention;

[0018] Figure 3 It is a top view of a novel air film hole structure with a connecting groove of the present invention;

[0019] Figure 4 It is an oblique view of a novel air film hole structure with a connecting groove of the present invention;

[0020] Figure 5 This is an example effect diagram.

[0021] Reference numerals in the figure: 1. first cylindrical hole structure; 2. second cylindrical hole structure; 3. connecting groove structure. DETAILED DESCRIPTION

[0022] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] like Figures 1 to 4 As shown, an embodiment of the present invention provides a new type of air film hole with a connecting groove, including a first cylindrical hole structure 1, a second cylindrical hole structure 2 and a connecting groove structure 3. The first cylindrical hole structure 1 and the second cylindrical hole structure 2 have the same structure, and the first cylindrical hole structure 1 and the second cylindrical hole structure 2 are symmetrically distributed relative to the center line of the connecting groove structure 3, and the two ends of the connecting groove structure 3 are respectively connected to one end of the first cylindrical hole structure 1 and one end of the second cylindrical hole structure 2, and the other end of the first cylindrical hole structure 1 and the other end of the second cylindrical hole structure 2 both extend in a direction close to the center line of the connecting groove structure 3.

[0025] Since the first cylindrical hole structure 1 and the second cylindrical hole structure 2 have the same structure and are arranged symmetrically with each other, the subsequent description will only take the first cylindrical hole structure 1 as an example, and the second cylindrical hole structure 2 will not be described in detail. Figures 1 to 4 The x, y, and z in the figure are coordinate system labels.

[0026] Specifically, in the vertical projection plane, the angle between the axis of the first cylindrical hole structure 1 and the midline of the connecting groove structure 3 is α, wherein 0<α≤18°.

[0027] The connecting groove structure 3 connects two cylindrical hole structures with spanwise deflection angles, and the resulting combined structure increases the outlet area of ​​the cylindrical hole structure, greatly increases the coverage area of ​​the cold air along the spanwise direction, and greatly improves the downstream air film cooling effect. At the same time, the cold air in the two cylindrical hole structures with spanwise deflection angles diffuses in the connecting groove 3, significantly reducing the cold air outlet momentum, and the cold air has a good degree of adhesion to the wall, effectively solving the problem of cold air blowing away from the wall under high blowing ratios.

[0028] It should be noted that the angle α between the axis of the first cylindrical hole structure 1 and the midline of the connecting groove structure 3 is the spanwise deviation angle. The existence of the spanwise deviation angle α can increase the upper limit of the width of the connecting groove, and the angle can be changed according to specific needs.

[0029] Preferably, the angle between the end surface of the other end of the first cylindrical hole structure 1 and the axis of the first cylindrical hole structure 1 is γ, wherein 30°≤γ≤55°.

[0030] The above structure can optimize the injection direction of the cold air, enhance the covering effect of the air film, effectively reduce the risk of the cold air blowing off the wall under high blowing ratio, and improve the cooling efficiency and thermal protection performance of the turbine blades.

[0031] The axial length of the first cylindrical hole structure 1 is L1, and the diameter of the first cylindrical hole structure 1 is D, wherein 2.8D≤L1≤8D. The connection length between the connecting groove structure 3 and the first cylindrical hole structure 1 at the axial position is L2, wherein 0.3L1≤L2≤0.7L1.

[0032] The above scheme achieves optimized distribution of cold air flow and effective reduction of momentum, thereby increasing the cold air coverage area and uniformity of the air film holes, significantly improving the cooling efficiency of the turbine blades, while maintaining structural strength and low processing costs, providing an innovative solution for efficient cooling of gas turbine turbine blades.

[0033] like Figure 4 As shown, the cross section of the connecting groove structure 3 is a trapezoidal structure. The groove width of the connecting groove structure 3 is H, where 0.4D≤H≤0.8D; the upper base of the connecting groove structure 3 is W1, where 3D≤W1≤5.5D; the lower base of the connecting groove structure 3 is W2, where 3D≤W2≤6D, and W2>W1. The angle between the hypotenuse and the lower base of the connecting groove structure 3 is β, where 55°≤β≤90°.

[0034] The design of the connecting groove structure 3 in a trapezoidal shape effectively expands the outlet area of ​​the air film hole and promotes the uniform distribution of the cold air on the blade surface. This structure not only increases the cold air coverage, but also reduces the outlet momentum by diffusing the cold air in the connecting groove, thereby increasing the degree of cold air adhesion on the wall surface, solving the problem of cold air blowing away from the wall surface under high blowing ratio, significantly improving the air film cooling efficiency, simplifying the processing process and reducing costs.

[0035] It should be noted that the diameter D of the first cylindrical hole structure 1 in the embodiment of the present invention has a value range as follows: 0.45 mm ≤ D ≤ 1.5 mm.

[0036] A specific embodiment is now provided, and specific air film cooling structure parameters are as follows: the diameter D of the first cylindrical hole structure 1 and the second cylindrical hole structure 2 with spanwise deflection angles is 1 mm, and the spanwise deflection angle α is 10°; the groove width H of the connecting groove structure 3 is 0.6D, the upper bottom W1 is 3.3D, the lower bottom W2 is 3.7D, and the angle β is 70°; the flow direction inclination angle γ of the first cylindrical hole structure 1 and the second cylindrical hole structure 2 to the connecting groove is 30°, the radial length L1 of the first cylindrical hole structure 1 and the second cylindrical hole structure 2 is 6D, and the radial length L2 of the connecting groove is 0.5L1.

[0037] like Figure 5 As shown in the figure, the upper part is a schematic diagram of the air film cooling effect at the cold air outlet of the traditional cylindrical hole, and the lower part is a schematic diagram of the air film cooling effect at the cold air outlet of the new air film hole with a connecting groove structure. The depth of the color represents the cooling efficiency of the air film. The darker the color, the greater the air film cooling efficiency, and the lighter the color, the lower the air film cooling efficiency. From the comparison of the upper and lower figures, it can be seen that compared with the traditional cylindrical hole, the new air film hole structure with a connecting groove structure increases the span-wise coverage area of ​​the cold air, significantly improves the uniformity of the cold air distribution downstream of the hole, and greatly improves the air film cooling effect downstream of the hole.

[0038] The new air film hole structure with connecting grooves can also change the shape of the connecting groove structure 3, including crescent-shaped connecting grooves, corrugated connecting grooves, etc. Changing the shape of the connecting groove structure 3 can further improve the uniformity of the downstream cold air and thus enhance the cooling effect. However, it will also increase the complexity of processing, so the new air film hole structure with connecting grooves of different shapes can be used according to the specific requirements of different parts of the turbine blade.

[0039] Of course, the present invention is not limited to the embodiments described above, and all related technical solutions belonging to the same inventive concept should be within the protection scope of the present invention.

[0040] The present invention also provides a turbine blade, comprising the novel air film hole with a connecting groove. Compared with the prior art solution, the turbine blade has the following beneficial effects:

[0041] 1. The connecting groove structure connects two cylindrical hole structures with spanwise deflection angles, and the resulting combined structure increases the outlet area of ​​the cylindrical hole structure, greatly increases the coverage area of ​​the cold air along the spanwise direction, and greatly improves the downstream air film cooling effect. At the same time, the cold air in the two cylindrical hole structures with spanwise deflection angles diffuses in the connecting groove, significantly reducing the cold air outlet momentum, and the cold air has a good degree of adhesion to the wall, effectively solving the problem of cold air blowing away from the wall under high blowing ratios.

[0042] 2. The connecting groove structure connects the discrete cylindrical hole structures, which effectively solves the problem of no cold air coverage between the traditional cylindrical hole structures and significantly improves the uniformity of cold air distribution downstream of the cylindrical hole structure, thereby improving the uniformity of the surface temperature of the turbine blades, reducing the thermal stress of the blades, and increasing the life of the blades.

[0043] 3. The connecting groove structure adds a connecting groove on the basis of the cylindrical hole structure, and the processing difficulty and processing cost are relatively low. The hole type can also directly transform the discrete cylindrical air film holes on the existing turbine blades, greatly reducing the design and manufacturing costs.

[0044] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other, and with each other.

Claims

1. A new type of air film hole with a connecting groove, characterized in that: The invention comprises a first cylindrical hole structure (1), a second cylindrical hole structure (2) and a connecting groove structure (3); the first cylindrical hole structure (1) and the second cylindrical hole structure (2) have the same structure, and the first cylindrical hole structure (1) and the second cylindrical hole structure (2) are symmetrically distributed relative to the center line of the connecting groove structure (3); two ends of the connecting groove structure (3) are respectively connected to one end of the first cylindrical hole structure (1) and one end of the second cylindrical hole structure (2); and the other end of the first cylindrical hole structure (1) and the other end of the second cylindrical hole structure (2) both extend in a direction close to the center line of the connecting groove structure (3).

2. The novel air film hole with connecting groove according to claim 1 is characterized in that: In the vertical projection plane, the angle between the axis of the first cylindrical hole structure (1) and the midline of the connecting groove structure (3) is α, wherein 0<α≤18°.

3. The novel air film hole with connecting groove according to claim 1 is characterized in that: The angle between the end surface of the other end of the first cylindrical hole structure (1) and the axis of the first cylindrical hole structure (1) is γ, wherein 30°≤γ≤55°.

4. The novel air film hole with connecting groove according to claim 1 is characterized in that: The axial length of the first cylindrical hole structure (1) is L1, and the diameter of the first cylindrical hole structure (1) is D, wherein 2.8D≤L1≤8D.

5. The novel air film hole with connecting groove according to claim 4 is characterized in that: The connection length between the connecting groove structure (3) and the first cylindrical hole structure (1) at the axial position is L2, wherein 0.3L1≤L2≤0.7L1.

6. The novel air film hole with connecting groove according to claim 4 is characterized in that: The cross section of the connecting groove structure (3) is a trapezoidal structure.

7. The novel air film hole with connecting groove according to claim 6 is characterized in that: The groove width of the connecting groove structure (3) is H, wherein 0.4D≤H≤0.8D; the upper base of the connecting groove structure (3) is W1, wherein 3D≤W1≤5.5D; the lower base of the connecting groove structure (3) is W2, wherein 3D≤W2≤6D, and W2>W1.

8. The novel air film hole with connecting groove according to claim 6 is characterized in that: The included angle between the hypotenuse and the lower bottom of the connecting groove structure (3) is β, wherein 55°≤β≤90°.

9. The novel air film hole with connecting groove according to any one of claims 4 to 8, characterized in that: 0.45mm≤D≤1.5mm.

10. A turbine blade, comprising a novel air film hole with a connecting groove, characterized in that: The novel air film hole with connecting grooves is the novel air film hole with connecting grooves as claimed in any one of claims 1 to 9.

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