A turbine blade and a method for processing special-shaped air outlet holes

Abstract

The present invention discloses a turbine blade and a method for processing a special-shaped air outlet hole, wherein a turbine blade comprises a blade body, wherein the trailing edge section, the pressure surface and the blade root of the blade body are respectively provided with a plurality of special-shaped air outlet holes, and the special-shaped air outlet holes comprise a cylindrical air inlet section and a trumpet-shaped outlet extension section. The present invention can expand the cold air coverage area in the extension direction and maintain good air film cooling efficiency by setting the outlet extension end of the hole structure into a trumpet shape; and by using a composite process of electric spark machining and laser machining, the two are coordinated to achieve efficient and high-precision machining of the special-shaped air outlet holes.

Description

Technical Field

[0001] The invention relates to the technical field of turbine blades, and in particular to a turbine blade and a method for processing a special-shaped air outlet hole. Background Art

[0002] Turbine blades are subjected to huge thermal and aerodynamic loads in high-temperature and high-pressure environments such as aircraft engines and gas turbines. Therefore, turbine blades are often designed with cooling cavities inside and air outlets outside, which work together to reduce the temperature of the blade surface through cooling airflow to ensure long-term stable operation of the blade in high-temperature environments. However, the air outlets of turbine blades are mostly cylindrical and linear, and the cooling effect is not ideal. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a turbine blade with good cooling effect and a method for processing special-shaped air outlet holes.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution: a turbine blade, including a blade body, wherein the trailing edge section, pressure surface and blade root of the blade body are respectively provided with a plurality of special-shaped air outlet holes, and the special-shaped air outlet holes include a cylindrical air inlet section and a trumpet-shaped outlet expansion section.

[0005] Furthermore, the special-shaped air outlet holes on the trailing edge section are arranged along the length direction of the blade body, the special-shaped air outlet holes on the pressure surface are arranged along the curved extension direction of the pressure surface, and the special-shaped air outlet holes on the blade root are arranged from the leading edge section toward the middle section.

[0006] Furthermore, the special-shaped air outlet holes on the trailing edge section are arranged in multiple rows along the length direction of the blade body.

[0007] Furthermore, the special-shaped air outlet holes on the blade root are arranged in two rows from the leading edge section to the middle section.

[0008] Furthermore, the angle formed between the generatrix of the outlet expansion section and the axis of the air inlet section is 3°.

[0009] Furthermore, the taper of the special-shaped air outlet is 3°.

[0010] Furthermore, the average aperture of the special-shaped air outlet holes on the trailing edge segment is in the range of 0.85-1.05 mm.

[0011] Furthermore, the average pore size of the special-shaped air outlet holes on the pressure surface is in the range of 0.85-1.05 mm.

[0012] Furthermore, the average aperture of the special-shaped air outlet holes on the blade root is in the range of 0.80-1.00 mm.

[0013] A method for processing a special-shaped vent hole comprises the following steps:

[0014] S1. The outlet section of the special-shaped air outlet hole is processed on the blade body by an electrospark machining method;

[0015] S2. Apply protective paint to the corresponding special-shaped air outlet holes on the blade body;

[0016] S3. The outlet extension section of the special-shaped outlet hole is processed by laser;

[0017] S4. Surface treatment and finishing are performed on the hole wall of the special-shaped vent hole.

[0018] The beneficial effects of the present invention are embodied in:

[0019] The turbine blade and the processing method of the special-shaped air outlet hole of the present invention can expand the cold air coverage area in the extension direction and maintain good air film cooling efficiency by setting the outlet extension end of the hole structure into a trumpet shape; through the composite process of electrospark machining and laser machining, the two are coordinated to achieve efficient and high-precision machining of the special-shaped air outlet hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the blade body of the present invention;

[0021] Figure 2 This is a cross-sectional view of the special-shaped vent structure of the present invention;

[0022] Figure 3 This is a schematic diagram of the simulated blade surface temperature according to the fourth embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of a simulated internal cold air outflow state according to a fourth embodiment of the present invention;

[0024] Figure 5 It is a schematic diagram of the transverse section metallographic structure of the special-shaped vent hole after processing according to the present invention.

[0025] The components in the accompanying drawings are marked as follows: 1. blade body; 101. trailing edge section; 102. pressure surface; 103. blade root; 104. leading edge section; 105. middle section; A. special-shaped air outlet; A1. air inlet section; A2. outlet expansion section. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] See also Figure 1 , 2 .

[0028] Example 1

[0029] The turbine blade of the present invention comprises a blade body 1, wherein the trailing edge section 101, the pressure surface 102 and the blade root 103 of the blade body 1 are respectively provided with a plurality of special-shaped air outlet holes A, and the special-shaped air outlet holes A comprise a cylindrical air inlet section A1 and a trumpet-shaped outlet expansion section A2.

[0030] In this embodiment, the special-shaped air outlet hole A on the trailing edge section 101 is arranged along the length direction of the blade body 1, the special-shaped air outlet hole A on the pressure surface 102 is arranged along the curved extension direction of the pressure surface 102, and the special-shaped air outlet hole A on the blade root 103 is arranged from the leading edge section toward the middle section.

[0031] In this embodiment, the special-shaped air outlet holes A on the trailing edge section 101 are arranged in multiple rows along the length direction of the blade body 1 .

[0032] In this embodiment, the special-shaped air outlet holes A on the blade root portion 103 are arranged in two rows from the leading edge section 104 toward the middle section 105 .

[0033] In this embodiment, the angle formed between the generatrix of the outlet extension section A2 and the axis of the air inlet section A1 is 3°.

[0034] In this embodiment, the taper of the special-shaped air outlet hole A is 3°.

[0035] In this embodiment, the average aperture of the special-shaped air outlet holes A on the trailing edge section 101 is 0.85 mm.

[0036] In this embodiment, the average aperture of the irregular-shaped air outlet holes A on the pressure surface 102 is 0.85 mm.

[0037] In this embodiment, the average aperture of the special-shaped air outlet holes A on the blade root portion 103 is 0.80 mm.

[0038] A method for processing a special-shaped vent hole comprises the following steps:

[0039] S1. Processing the outlet section A1 of the special-shaped outlet hole A on the blade body 1 by an electrospark machining method; in this step, metal is removed by electrospark discharge to form a predetermined hole profile. Since electrospark machining is suitable for high-hardness materials, electrospark machining can be applied to areas with higher hardness of the turbine blade (such as the alloy matrix) to quickly remove materials and preliminarily form a hole profile;

[0040] S2. Apply protective paint to the processing position of the corresponding special-shaped air outlet hole A of the blade body 1;

[0041] S3. The outlet extension section A2 of the special-shaped outlet hole A is processed by laser; in this step, the high processing precision of laser processing can accurately control the aperture, hole shape and surface quality as needed;

[0042] S4. Surface treatment and finishing of the hole wall of the special-shaped outlet hole A. In this step, after laser finishing, the hole wall of the cooling hole is further surface treated, such as laser deburring and deoxidation, to ensure that the hole wall is smooth and free of overheating damage. This step can further improve the surface quality of the cooling hole and reduce the blockage of the cooling fluid channel caused by high surface roughness during the actual use of the blade.

[0043] Taking the processing of a special-shaped hole with a diameter of 0.85 mm as an example, some steps are as follows:

[0044] Clamp the blade on the tooling;

[0045] Process the air inlet section A1, perform five-axis calibration, camera center inspection, cross punching, and energy testing on the equipment. After the test, start processing a straight hole with a diameter of 0.85mm. Processing method: circular cutting, each pulse energy: 3-4J frequency: 10-25HZ pulse duration: 1.5-2s focal length: 2-3mm, nozzle model: Nozzle STK3 F200 M32Φ2.0-28L158 process gas: oxygen, air pressure: 4-7bar;

[0046] Laser repair of non-through holes in workpieces, using non-detection repair mode, and using small energy to repair holes after aligning the hole position. Each pulse energy: 1-2J frequency: 10-25HZ pulse duration: 1-1.5s focal length: 2-3mm, nozzle model: Nozzl e STK3 F200 M32Φ2.0-28L158 process gas: oxygen, pressure: 4-7bar;

[0047] Process the outlet extension section A2, perform five-axis calibration, camera center inspection, cross punching, and energy testing on the equipment. After the test, start processing the forming hole with a diameter of 0.85mm. Energy ratio: 20-33 Pulse width: 150-300ns Frequency: 60-80Hz Processing speed: 600-630mm / min Focal length: 0;

[0048] The cross section of the special-shaped vent hole A obtained by final processing is as follows Figure 5 As shown, the remelted layer on its inner surface is about 11 microns.

[0049] Example 2

[0050] It should be noted that, in this embodiment, compared with Embodiment 1, only the average aperture size of the irregular-shaped air outlet holes A on the trailing edge section 101 , the pressure surface 102 , and the blade root 103 is different.

[0051] In this embodiment,

[0052] The average aperture of the special-shaped air outlet holes A on the trailing edge section 101 is 0.90 mm;

[0053] The average aperture of the special-shaped air outlet holes A on the pressure surface 102 is 0.90 mm;

[0054] The average aperture of the irregular air outlet holes A on the blade root 103 is 0.85 mm.

[0055] Example 3

[0056] It should be noted that, in this embodiment, compared with Embodiment 1, only the average aperture size of the irregular-shaped air outlet holes A on the trailing edge section 101 , the pressure surface 102 , and the blade root 103 is different.

[0057] In this embodiment, the average aperture of the irregular air outlet holes A on the trailing edge section 101 is 0.95; the average aperture of the irregular air outlet holes A on the pressure surface 102 is 0.95; and the average aperture of the irregular air outlet holes A on the blade root 103 is 0.9.

[0058] Example 4

[0059] It should be noted that, in this embodiment, compared with Embodiment 1, only the average aperture size of the irregular-shaped air outlet holes A on the trailing edge section 101 , the pressure surface 102 , and the blade root 103 is different.

[0060] In this embodiment,

[0061] The average aperture of the special-shaped air outlet holes A on the trailing edge section 101 is 1 mm;

[0062] The average aperture of the irregular shaped air outlet holes A on the pressure surface 102 is 1 mm;

[0063] The average aperture of the special-shaped air outlet holes A on the blade root 103 is 0.95 mm.

[0064] Example 5

[0065] It should be noted that, in this embodiment, compared with Embodiment 1, only the average aperture size of the irregular-shaped air outlet holes A on the trailing edge section 101 , the pressure surface 102 , and the blade root 103 is different.

[0066] In this embodiment,

[0067] The average aperture of the special-shaped air outlet holes A on the trailing edge section 101 is 1.05 mm;

[0068] The average aperture of the irregular vent holes A on the pressure surface 102 is 1.05 mm;

[0069] The average aperture of the irregular air outlet holes A on the blade root 103 is 1 mm.

[0070] The simulation of the cooling effect of the above embodiment on the turbine blades yields the following table:

[0071]

[0072]

[0073] Wherein, SH is the average aperture of the special-shaped air outlet hole A at the trailing edge section 101, PLP is the average aperture of the special-shaped air outlet hole A at the blade root 103, and BTP is the average aperture of the special-shaped air outlet hole A at the pressure surface 102;

[0074] After simulation calculation, according to the air film hole making scheme of Example 4, see Figure 3 , the blade surface temperature is relatively uniform, the temperature is low, and the cooling effect is more reasonable, see Figure 4 , and the air flow at the outlet position is large, which is suitable as a design cooling parameter for product processing.

[0075] In summary, the turbine blade and the method for processing special-shaped air outlet holes of the present invention can expand the cold air coverage area in the widthwise direction and maintain good air film cooling efficiency by setting the outlet extension end A2 of the hole structure into a trumpet shape; through the composite process of electrospark machining and laser machining, the two are coordinated to achieve efficient and high-precision machining of special-shaped air outlet holes.

[0076] It should be understood that the examples and implementation modes described herein are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art may make various modifications or changes based on the examples and implementation modes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0077] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, back, etc., then the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0078] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A turbine blade, characterized in that: The invention comprises a blade body (1) and a cooling cavity arranged in the blade body (1), and is characterized in that a plurality of special-shaped air outlet holes (A) are respectively provided on the trailing edge section (101), the pressure surface (102) and the blade root (103) of the blade body (1), and the special-shaped air outlet holes (A) comprise a cylindrical air inlet section (A1) and a trumpet-shaped outlet expansion section (A2).

2. The turbine blade according to claim 1, characterized in that The irregular air outlet holes (A) on the trailing edge section (101) are arranged along the length direction of the blade body (1), the irregular air outlet holes (A) on the pressure surface (102) are arranged along the curved extension direction of the pressure surface (102), and the irregular air outlet holes (A) on the blade root (103) are arranged from the leading edge section toward the middle section.

3. The turbine blade according to claim 2, characterized in that The special-shaped air outlet holes (A) on the trailing edge section (101) are arranged in a plurality of rows along the length direction of the blade body (1).

4. The turbine blade according to claim 2, characterized in that The special-shaped air outlet holes (A) on the blade root (103) are arranged in two rows from the leading edge section (104) toward the middle section (105).

5. The turbine blade according to claim 1, characterized in that The angle formed between the generatrix of the outlet expansion section (A2) and the axis of the air inlet section (A1) is 3°.

6. The turbine blade according to claim 1, characterized in that The taper of the special-shaped air outlet (A) is 3°.

7. The turbine blade according to claim 3, characterized in that The average aperture of the special-shaped air outlet holes (A) on the trailing edge section (101) is in the range of 0.85-1.05 mm.

8. The turbine blade according to claim 3, characterized in that The average pore diameter of the special-shaped air outlet holes (A) on the pressure surface (102) is in the range of 0.85-1.05 mm.

9. The turbine blade according to claim 3, characterized in that The average aperture of the special-shaped air outlet holes (A) on the blade root (103) is in the range of 0.80-1.00 mm.

10. A method for processing a special-shaped vent hole, characterized in that: The following steps are involved: S1. The outlet section (A1) of the special-shaped air outlet hole (A) is processed on the blade body (1) by an electrospark machining method; S2. Apply protective paint to the processing position of the corresponding special-shaped air outlet hole (A) of the blade body (1); S3. The outlet extension section (A2) of the special-shaped outlet hole (A) is processed by laser; S4. Surface treatment and finishing are performed on the hole wall of the special-shaped vent hole (A).

Images