Gas film cooling structure with orifice recess and engine

Abstract

The application provides a gas film cooling structure with an orifice recess and an engine. The gas film cooling structure with the orifice recess comprises a gas film orifice, a recess structure and a wall structure; the wall structure is provided with the gas film orifice and the recess structure, the gas film orifice penetrates through the wall structure and the recess structure; and the inner wall of the recess structure is communicated with the gas film orifice. Preferably, the wall structure comprises an end wall, the recess structure is directly provided on the end wall, the front part of the recess structure is a concave curved surface, the rear part is a convex surface, and the opening contour of the recess structure is a crescent shape. In another preferred example, the wall structure comprises an end wall and a thermal barrier coating layer coated on the end wall; and the recess structure is partially or entirely provided on the thermal barrier coating layer. The application has a simple shape, is easy to process and can be applied to a thin wall surface. In addition to directly providing the recess structure on the metal end wall, the application can also process the recess structure in the thermal barrier coating layer on the metal wall surface, which is simple to process; and this scheme does not need to expand the hole in the metal wall surface, so that the structural strength of the metal wall surface can be maintained.

Description

Technical Field

[0001] This invention relates to the field of high-temperature component cooling and heat transfer, specifically to a film cooling structure with recessed orifices and an engine. Background Technology

[0002] Film cooling is a common cooling method for the surfaces of high-temperature components in aero-engines and gas turbines, including turbine blades and combustion chambers. Hypersonic vehicles also experience high temperatures due to aerodynamic heating, making film cooling a primary technology for thermal protection of their high-temperature surfaces. Improving film cooling efficiency reduces cooling air consumption, thereby increasing the thermal efficiency and work capacity of aero-engines and gas turbines, and ultimately enhancing the performance of high-speed vehicles.

[0003] Current film cooling orifices are inclined cylindrical holes with an angle of 20-80°. While simple to manufacture, they result in low film cooling efficiency. Furthermore, under high cooling air blowing ratios, the cooling efficiency of cylindrical film cooling orifices drops rapidly, leading to film cooling failure. Therefore, improving the structure of film cooling orifices and the flow structure at the orifice to enhance film cooling efficiency is crucial.

[0004] One current approach to improve the efficiency of film cooling is to expand the film cooling holes on the wall surface to obtain enhanced film cooling performance. However, expanding film cooling holes require a thicker wall to form a gradually expanding hole. If the wall is thin, this method cannot be used. Furthermore, expanding holes also have drawbacks such as high processing difficulty, high cost, and reduced wall strength.

[0005] Patent document CN 111042872 A discloses a transversely expanding meridional contraction groove-shaped gas film pore, which relates to combustion

[0006] High-temperature turbine cooling technology for gas turbines. This invention utilizes a film cooling orifice constructed in a channel-shaped cross-section, exhibiting lateral expansion and meridional contraction along the flow direction. The channel-shaped cross-section is generally rectangular, with rounded corners. The diameter d corresponding to each rounded corner is between 0.2D and 0.4D, where D is the diameter of the reference circular orifice. However, this invention still belongs to the expansion-type orifice category, and still suffers from inconvenient processing and reduced wall strength. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the purpose of this invention is to provide a film cooling structure with recessed orifices, an engine, and an engine.

[0008] A film cooling structure with recessed orifices according to the present invention includes film orifices, recessed structure and wall structure;

[0009] The wall structure is provided with air film holes and recessed structures, and the air film holes penetrate the wall structure and the recessed structures.

[0010] The inner wall of the recessed structure is connected to the air film pores.

[0011] Preferably, the wall structure includes an end wall, and the recessed structure is directly formed on the end wall; the front part of the recessed structure is a concave curved surface, the rear part is a convex surface, and the opening outline of the recessed structure is crescent-shaped.

[0012] Preferably, the wall structure includes an end wall and a thermal barrier coating applied to the end wall;

[0013] The recessed structure is partially or entirely formed on the thermal barrier coating.

[0014] Preferably, the air film pores are located within the recessed structure;

[0015] The recessed structure includes a first surface and a second surface that are interconnected;

[0016] The first curved surface is recessed into the wall along the wall structure;

[0017] The second curved surface is convex, protruding outwards in the direction of the main high-temperature flow, with the middle of the second curved surface being the most convex, and the two lateral sides of the second curved surface extending downstream.

[0018] Preferably, the first surface is a part of a sphere; the second surface is a cylindrical surface or a conical surface.

[0019] Preferably, the air film pores are cylindrical, and the inclination angle between the air film pores and the extension direction of the wall structure is 20-80°; the edges of the air film pore openings are rounded, with the lateral rounding being even larger.

[0020] Preferably, the second curved surface intersects the first curved surface at the bottom of the concave structure;

[0021] The outer edge of recess 12 is rounded.

[0022] Preferably, the angle between the second curved surface and the wall structure is β, and the value of β ranges from 10 to 100 degrees.

[0023] Preferably, the recessed structure has a first included angle and a second included angle that gradually taper and face downstream, and the first included angle and the second included angle are arranged symmetrically.

[0024] Both the first included angle and the second included angle are the included angles between the concave first curved surface and the convex second curved surface.

[0025] An engine according to the present invention includes the aforementioned film cooling structure with recessed orifices.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention adopts a recessed structure design, which connects the recessed structure with the air film pores. The recessed structure has a simple shape and is easy to process. The air film cooling structure with recessed pores does not need to be gradually formed with a thick wall surface, and can be applied to thinner walls.

[0028] 2. In addition to directly creating a recessed structure on the end wall, the present invention can also use a more convenient processing method, namely, processing the recessed structure in the thermal barrier coating on the metal wall surface. Laser processing of the thermal barrier coating structure only requires processing two curved surface structures, thus making the processing simpler. Furthermore, creating a recessed structure in the thermal barrier coating does not require enlarging holes in the metal wall surface, thus maintaining the structural strength of the metal wall surface. Attached Figure Description

[0029] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic cross-sectional view of the present invention;

[0031] Figure 2 This is a top view of the structure of the present invention;

[0032] Figure 3 This is a three-dimensional structural diagram of the present invention;

[0033] Figure 4 This is a schematic diagram illustrating the principle of the present invention;

[0034] Figure 5 This is a front view structural diagram of the present invention;

[0035] Figure 6 This is a schematic diagram of the recessed structure formed on the thermal barrier coating according to the present invention.

[0036] The diagram shows:

[0037] Detailed Implementation

[0038] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0039] This invention provides a film cooling structure with recessed orifices, such as... Figure 1-6As shown, it includes an air film aperture 36, a recessed structure 12, and a wall structure 32 and a recessed structure 12; the wall structure 32 has an air film aperture 36 and a recessed structure 12, and the inner wall of the recessed structure 12 is connected to the air film aperture 36. The air film aperture 36 is a cylindrical aperture, that is, the diameter of the air film aperture 36 is the same everywhere, and it is a non-expansion type air film aperture. The inclination angle between the air film aperture 36 and the extension direction of the wall structure 32 is 20-80°. The edge of the air film aperture 40 is rounded, and the rounding radius on the left and right sides is larger, with the rounding radius being 0.01-0.1 times the diameter of the air film aperture.

[0040] In one embodiment, the wall structure 32 includes an end wall, and the recessed structure 12 is directly formed on the end wall. The front part of the recessed structure 12 is a concave curved surface, and the rear part is a convex surface. The projected surface of the opening contour of the recessed structure 12 is crescent-shaped. The recess depth is 0.05-0.5 times the recess diameter. In another embodiment, such as... Figure 6 As shown, the wall structure 32 includes an end wall and a thermal barrier coating 50 coated on the end wall. The recessed structure 12 is partially or entirely formed on the thermal barrier coating 50, such as... Figure 2-4 As shown, the projection surface of the opening contour of recess 12 is crescent-shaped, and the recess depth is 0.05-0.5 times the recess diameter.

[0041] The air film pore 36 has an air film pore 40 located within the recessed structure 12; the recessed structure 12 includes a first curved surface 10 and a second curved surface 20 that are connected to each other.

[0042] The first curved surface 10 is radially recessed along the wall structure 32. The first curved surface 10 is an inwardly concave surface located at the front part of the recessed structure 12 and extends to the rear part of the recessed structure 12. The first curved surface 10 intersects with the wall structure surface 30 to form a first arc line 1, which is the leading edge of the recessed structure 12. In an embodiment where the wall structure 32 only includes an end wall, the wall structure surface 30 is the surface of the end wall; in an embodiment where the wall structure 32 includes an end wall and a thermal barrier coating coated on the end wall, the wall structure surface 30 is the surface of the thermal barrier coating.

[0043] In a preferred embodiment, the first curved surface 10 is part of a sphere, and the air film pore 36 passes mostly through the first curved surface 10 of the recessed structure 12.

[0044] The second curved surface 20 is convex, protruding outward in the direction of the main high-temperature current 100, and the middle of the second curved surface 20 is the most convex, while the lateral sides of the second curved surface 20 extend downstream. Preferably, the second curved surface 20 is a cylindrical surface, a conical surface, or an inclined cylindrical surface or conical surface.

[0045] The second curved surface 20 intersects the first curved surface 10 at the bottom of the recessed structure 12, that is, the bottom surface of the second curved surface 20 intersects the bottom surface of the first curved surface 10, and the outer edge of the recess 12 is rounded with a rounding radius of 0.01-0.1 times the diameter of the recess. The angle between the second curved surface 20 and the wall structure surface 30 is β, and the value of β ranges from 10 to 100 degrees. Preferably, the range of the β angle is 30-90 degrees.

[0046] The second curved surface 20 intersects with the wall structure surface 30 to form a second arc 2, which is the rear edge of the recessed structure 12. The first arc 1 at the front edge and the second arc 2 at the rear edge of the recessed structure 12 intersect at points A and B on both sides. The first arc 1 at the front edge and the second arc 2 at the rear edge of the recessed structure 12 form a crescent-shaped recessed opening on the wall structure surface 30. The crescent-shaped recessed opening has a first included angle 14 and a second included angle 16 that gradually narrow and face downstream on both sides. The first included angle 14 and the second included angle 16 are symmetrically arranged. The first included angle 14 and the second included angle 16 are both the angles between the concave first curved surface 10 and the convex second curved surface 20. The second curved surface 20 is located near the air film orifice 40 of the cylindrical air film orifice 36 and partially blocks the flow direction of the cold air jet 34 inside the air film orifice, thereby reducing the flow volume of the cold air jet and enhancing the lateral diffusion of the cold air jet inside the recessed structure 12, and causing some of the cold air to be discharged along the first included angle 14 and the second included angle 16 on both sides.

[0047] The working principle of this invention is as follows:

[0048] like Figure 3 , Figure 4 As shown, when the external high-temperature mainstream 100 sweeps across the wall structure surface 30, a horseshoe vortex is generated at the edge of the first curved surface 10 at the front of the recessed structure 12. The horseshoe vortex branch 102 moves spirally downstream along the two lateral curved surfaces of the recessed structure 12, close to the two lateral edges of the recess. The horseshoe vortex branch 102 is discharged obliquely outward at the widest edge on both lateral sides of the crescent-shaped recessed structure 12. The horseshoe vortex branch 102 generated by the recessed structure 12 at the air film orifice reduces the interference of the high-temperature mainstream 100 on the cold air jet 34 at the air film orifice 40, which is conducive to a larger area of ​​cooling air film covering the downstream wall surface, thereby improving the cooling performance of the downstream wall surface.

[0049] The cold air jet 34 from the film cooling orifice impacts the second curved surface 20 of the recessed structure 12 at the orifice opening, causing the cold air jet 34 to diffuse laterally within the recessed structure 12. A portion of the cold air exits from the lateral angle regions on both sides of the recessed structure 12 (i.e., the first angle 14 and the second angle 16), forming vortices 204 and 206. The rotation direction of these vortices causes the cooling film to cover the wall surface. Another portion of the cold air jet from the film cooling orifice impacts the second curved surface 20, crosses its middle section, and flows downstream. Through interaction with the external high-temperature mainstream flow 100, it forms a counter-rotating vortex pair 210, or CRVP, downstream of the middle section of the film cooling orifice. The counter-rotating vortex pair 210 causes the cold air film on the wall surface to rise downstream and leave the wall structure surface 30, thus reducing the film cooling performance.

[0050] It is worth noting that vortices 204 and 206 are formed on the downstream wall surface in the lateral angle region at the rear of the recessed structure 12. Internal cold air is discharged from the lateral angle region. Since the outer wall surface (first curved surface 10) of the lateral angle region is concave, while the second curved surface 20 is convex, the rotation direction of the outflow vortices 204 and 206 in the lateral angle region is opposite to that of the adjacent anti-rotating vortex pair 210. The rotation direction of these vortices 204 and 206 is opposite to that of the anti-rotating vortex pair CRVP downstream of the middle of the recess. Therefore, vortices 204 and 206 resist the reducing effect of the anti-rotating vortex pair 210 on the downstream surface film cooling, thus facilitating better cold air coverage on the downstream wall surface of the film cooling orifice, thereby achieving higher film cooling performance. Furthermore, the second curved surface 20 of the recessed structure 12 is located near the downstream of the cylindrical film cooling orifice 40 and partially obstructs the film cooling jet 34.

[0051] In summary, this invention proposes a novel film cooling structure with a recessed orifice, comprising an internal cylindrical film cooling orifice 36, a recessed structure 12, and a wall structure 32. The film cooling orifice is located on the inner wall surface of the recessed structure 12. The front wall surface of the recessed structure 12 is a concave curved surface, and the rear wall surface is a convex wall surface. The convex surface at the rear is located near the downstream of the film cooling orifice and partially blocks the cooling jet from the film cooling orifice, promoting the lateral diffusion of cold air. The concave curved wall surface at the front of the recess generates horseshoe vortex pairs in the high-temperature, high-speed incoming flow, which are then discharged obliquely along the two sides of the recess. This reduces the interference of the high-temperature, high-speed mainstream flow on the cold air jet from the film cooling orifice, thus improving the film cooling performance. On the other hand, the concave curved surface at the front and the convex surface at the rear of the recess form a contracting angle region on both sides of the rear of the recess, which can discharge the cooling airflow within the recess and form vortices that suppress the anti-rotating vortex pairs, thereby improving the downstream film cooling performance.

[0052] Compared to conventional cylindrical film cooling holes, this invention exhibits superior film cooling performance under both low and high airflow ratios. Furthermore, the shallow recessed structure on wall structure 32 makes it suitable for thin-walled structures. Additionally, since there is no need to enlarge the holes in the metal wall, the structural strength of the metal wall is maintained. Besides directly creating recessed structures on the end wall, an even easier processing method can be used: machining the recessed structure within the thermal barrier coating on the metal wall. Laser machining of the thermal barrier coating structure requires only the processing of two curved surfaces, thus simplifying the process. Again, in this embodiment, the structural strength of the metal wall is maintained because there is no need to enlarge the holes in the metal wall.

[0053] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0054] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A film cooling structure with recessed orifices, characterized in that, It includes air film pores (36), recessed structures (12) and wall structures (32); The wall structure (32) is provided with an air film hole (36) and a recessed structure (12), and the air film hole (36) penetrates the wall structure (32) and the recessed structure (12). The inner wall of the recessed structure (12) is connected to the air film pore (36); The wall structure (32) includes an end wall, and the recessed structure (12) is directly opened on the end wall; the front part of the recessed structure (12) is an inwardly concave curved surface, the rear part is a convex surface, and the opening outline of the recessed structure (12) is crescent-shaped. The air film pore (36) has an air film pore (40) located within the recessed structure (12); The recessed structure (12) includes a first surface (10) and a second surface (20) that are connected to each other. The first curved surface (10) is recessed into the wall along the wall structure (32); The second curved surface (20) is convex, protruding towards the external high temperature mainstream (100) direction, and the middle of the second curved surface (20) is the most convex, and the two lateral sides of the second curved surface (20) extend downstream.

2. The film cooling structure with recessed orifices according to claim 1, characterized in that, The wall structure (32) includes an end wall and a thermal barrier coating (50) applied to the end wall. The recessed structure (12) is partially or entirely formed on the thermal barrier coating (50).

3. The film cooling structure with recessed orifices according to claim 1, characterized in that, The first surface (10) is a part of a sphere; the second surface (20) is a cylindrical surface or a conical surface.

4. The film cooling structure with recessed orifices according to claim 1, characterized in that, The air film pore (36) is a cylindrical pore, and the inclination angle between the air film pore (36) and the extension direction of the wall structure (32) is 20-80°; the edge of the air film pore (40) is rounded, and the lateral rounding is larger.

5. The film cooling structure with recessed orifices according to claim 1, characterized in that, The second surface (20) intersects the first surface (10) at the bottom of the concave structure (12); The outer edge of the recessed structure (12) is rounded.

6. The film cooling structure with recessed orifices according to claim 1, characterized in that, The angle between the second curved surface (20) and the wall structure (32) is β, and the value of β ranges from 10 to 100 degrees.

7. The film cooling structure with recessed orifices according to claim 3, characterized in that, The recessed structure (12) has a first included angle (14) and a second included angle (16) that gradually taper and face downstream, and the first included angle (14) and the second included angle (16) are arranged symmetrically. The first included angle (14) and the second included angle (16) are both the included angles between the concave first curved surface (10) and the convex second curved surface (20).

8. An engine, characterized in that, Includes the film cooling structure with recessed orifices as described in any one of claims 1-7.

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