Double-wall cooling structure of runway type impact hole

Abstract

The invention belongs to the technical field of cooling of turbine blades of gas turbines, and particularly relates to a double-wall cooling structure of runway type impact holes. Comprising an impact target surface, an impact bottom surface, a runway-shaped air inlet formed in the impact bottom surface, a turbulent flow assembly composed of rhombic first turbulent flow columns and water-drop-shaped second turbulent flow columns which are arranged in a staggered mode, and a cold air outlet formed in the impact target surface. Cooling gas impacts the target surface through the runway-shaped air inlet holes and then returns and diffuses, the range of a wing-shaped strong heat exchange area formed by the cooling gas is larger, and a downstream flow dead zone can be effectively reduced. And then the air flow is fully disturbed and homogenized through the turbulent flow assemblies in sequence, and finally a uniform air film is formed through the obtuse-angle-designed cold air outlet. By optimizing the internal flow structure, the heat exchange efficiency and the air film covering uniformity are improved, and the problem of cooling the tail edge of the turbine blade is effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine blade cooling technology, and particularly relates to a double-walled cooling structure with racetrack-shaped impact holes. Background Technology

[0002] The performance of gas turbine engines is highly dependent on the turbine inlet temperature; increasing this temperature can significantly increase engine thrust and thermal efficiency. Currently, the turbine inlet temperature of advanced aero engines far exceeds the temperature resistance limit of the blade materials themselves. Therefore, developing efficient cooling technologies is crucial to ensuring the normal operation of turbine blades in extreme high-temperature environments.

[0003] Among the various parts of turbine blades, the trailing edge region is a key and challenging area for cooling design because it is subjected to high-temperature mainstream combustion gas on both sides, has high convective heat transfer intensity, and has a small structural space.

[0004] To address this challenge, turbine blade trailing edges commonly employ a combined cooling method of "internal channel cooling + film cooling." Among these, the semi-slit structure is a typical and advanced trailing edge cooling solution. It removes a portion of the pressure surface wall, drawing out the internal cooling airflow to form a cooling film covering the blade surface, offering the dual advantages of reducing trailing edge thickness (optimizing aerodynamic performance) and providing excellent cooling. To ensure the mechanical strength of the semi-slit structure, the ribs of the internal cooling channels are typically extended to the slit surface, forming partition ribs.

[0005] However, the existing semi-slit structure with partitioned ribs has a significant drawback: the cooling airflow becomes unevenly distributed in the downstream region, resulting in a rapid decrease in cooling efficiency. This leads to localized high-temperature points and large temperature gradients in the downstream region of the semi-slit, thereby generating high thermal stress and posing a risk of damage to the trailing edge structure under long-term operation.

[0006] The root cause of this problem lies in the poor internal cooling airflow organization. Traditional structures such as circular impact holes are prone to creating "crescent-shaped" or "eye-shaped" flow dead zones (low heat transfer zones) on the impact target surface and downstream area, which prevents the cooling air from uniformly and effectively covering the entire heat transfer surface, ultimately affecting the uniformity of air film discharge.

[0007] Therefore, a double-walled cooling structure with racetrack-shaped impact holes is urgently needed to solve this problem. Summary of the Invention

[0008] The purpose of this invention is to provide a double-walled cooling structure for racetrack-shaped impact holes to solve the above-mentioned problems.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] A double-walled cooling structure for a racetrack-shaped impact hole includes:

[0011] A cooling chamber is provided inside the turbine guide vane, wherein an air inlet, a turbulence component, and a cold air outlet are sequentially arranged along the direction of cold air flow.

[0012] The cooling chamber includes two opposing walls, one of which is the impact target surface and the other is the impact bottom surface;

[0013] The air inlet is formed on the impact bottom surface. After the cooling gas enters through the air inlet, it impacts the impact target surface and bounces back from the impact target surface to the impact bottom surface, causing the cooling gas to diffuse in the cooling chamber.

[0014] The cold air outlet is located on the impact target surface;

[0015] The air intake has a racetrack-shaped structure.

[0016] Optionally, the aspect ratio of the air inlet is 1.5-2.5.

[0017] Optionally, the turbulence assembly includes a first turbulence section and a second turbulence section arranged sequentially along the direction of the cold gas flow channel, and the first turbulence section and the second turbulence section are fixed inside the cooling chamber.

[0018] Optionally, the first turbulence section includes a plurality of first turbulence columns, and a first turbulence channel is formed between the plurality of first turbulence columns. The air inlet end of the first turbulence channel is connected to the air outlet end of the air inlet, and the air outlet end of the first turbulence channel is connected to the air inlet end of the second turbulence section.

[0019] Optionally, the plurality of the first spoiler columns are arranged in two rows;

[0020] The number of the first deflector columns in the row near the air intake is one less than the number of the first deflector columns in the row away from the air intake;

[0021] The first spoiler column in the front row is located between the two corresponding first spoiler columns in the rear row;

[0022] The gap between the first turbulence columns forms the first turbulence channel.

[0023] Optionally, the second turbulence section includes a plurality of second turbulence columns, and a second turbulence channel is formed between the plurality of second turbulence columns. The air inlet end of the second turbulence channel is connected to the air outlet end of the first turbulence channel, and the air outlet end of the second turbulence channel is connected to the cold air outlet.

[0024] Optionally, multiple second spoiler columns may be arranged in a row;

[0025] The second turbulence column is either a first teardrop-shaped structure or a second teardrop-shaped structure;

[0026] In the multiple second turbulence columns in the same row, the first teardrop-shaped structure and the second teardrop-shaped structure are arranged at intervals;

[0027] The second teardrop-shaped structure of the second deflector column is arranged in a one-to-one correspondence with a row of the first deflector columns located near the air inlet;

[0028] The gap between the second turbulence columns forms the second turbulence channel.

[0029] Optionally, the cold air outlet and the impact bottom surface are connected by a cold air outlet slit, the cold air outlet slit is inclined, and the angle between the cold air outlet slit and the cooling cavity is an obtuse angle.

[0030] Optionally, the air inlet end of the cold air outlet slit smoothly transitions to the impact bottom surface.

[0031] Optionally, the edge of the air inlet smoothly transitions to the impact bottom surface.

[0032] Compared with the prior art, the present invention has the following advantages and technical effects:

[0033] This invention achieves significant technological advancements by designing the impact hole as a racetrack-shaped structure and optimizing its synergistic layout with the internal baffles and cool air outlet. The core effect lies in the wider jet generated by the racetrack-shaped impact hole, which directly expands and extends the "wing-shaped" high-heat-transfer region on the impact target and impact base surfaces, effectively reducing the downstream "eye-shaped" flow dead zone. This significantly improves the uniformity of coolant distribution within the double-walled structure. The optimized internal flow allows for more thorough impact heat transfer between the coolant and the wall surface, and more efficient convective heat transfer with the baffles, resulting in improved overall heat transfer efficiency. Finally, the homogenized airflow exits through the obtuse-angled coolant outlet slit, forming a more uniform and stable film cooling layer on the blade surface. This fundamentally solves the problem of rapid cooling efficiency decay and localized overheating in the downstream trailing edge region caused by uneven film distribution in existing technologies, helping to reduce blade thermal stress and improve engine reliability and lifespan. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1This is a schematic diagram of the structure of the present invention;

[0036] Figure 2 For the present invention Figure 1 Schematic diagram of the cross-sectional structure at point AA;

[0037] Figure 3 This is an isometric view of the structure of the present invention;

[0038] Figure 4 This is a structural diagram of the cold air outlet side of the present invention;

[0039] Figure 5 This is a structural diagram of the air inlet side of the present invention;

[0040] Among them, 1. air inlet; 2. first turbulence column; 3. second turbulence column; 4. cold air outlet; 5. impact target surface; 6. impact bottom surface. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Reference Figures 1 to 5 This invention discloses a double-walled cooling structure for a racetrack-shaped impact hole, comprising:

[0044] A cooling chamber is provided inside the turbine guide vane, and an air inlet 1, a turbulence assembly and a cold air outlet 4 are arranged sequentially along the direction of cold air flow in the cooling chamber;

[0045] The cooling chamber includes two opposing walls, one of which is the impact target surface 5 and the other is the impact bottom surface 6.

[0046] The air inlet 1 is located on the impact bottom surface 6. After the cooling gas enters through the air inlet 1, it impacts the impact target surface 5 and is rebounded from the impact target surface 5 to the impact bottom surface 6, causing the cooling gas to diffuse in the cooling chamber.

[0047] The cold air outlet 4 is located on the impact target surface 5;

[0048] The air intake 1 has a racetrack-shaped structure.

[0049] In the actual operation of the double-walled cooling structure with a racetrack-shaped impact hole of the present invention, the cooling gas first enters the cooling chamber through the air inlet 1. The air inlet 1 has a racetrack-shaped structure, which increases the air intake area compared to the traditional circular air inlet. After the cooling gas enters the cooling chamber, the cooling gas jet directly impacts the oppositely arranged impact target surface 5, forming a high-intensity heat transfer in the impact stagnation area. Subsequently, the airflow after impact diffuses along the impact target surface 5 in all directions, and is deflected back due to the limitation of the cavity space, impacting the impact bottom surface 6 again. This process forms a significantly expanded "wing-shaped" strong heat transfer area in the area below the air inlet 1. Compared with a circular air inlet, the wing-shaped strong heat transfer area generated by the racetrack-shaped air inlet 1 has a longer coverage area in the airflow direction, thereby effectively reducing the range of the "eye-shaped" low heat transfer area, i.e., the flow dead zone, that usually exists in the first row of turbulence components and the middle area of ​​the impact hole on the impact bottom surface 6, and improving the overall uniformity of cooling gas distribution in the cavity. Subsequently, the cooling gas, after undergoing impact heat exchange, continues to flow through the turbulence-dispersing component. This component, through its specific shape and arrangement, further agitates and mixes the airflow, enhancing convective heat transfer and making the airflow distribution more uniform. Finally, the fully organized and homogenized cooling gas is discharged through the cold gas outlet 4 located on the impact target surface 5, forming a uniformly covered and highly stable film cooling layer on the turbine guide vane surface. In summary, this structure, through the core design of the racetrack-shaped air inlet 1, in conjunction with the impact target surface 5, the impact bottom surface 6, and the turbulence-dispersing component, achieves the technical effects of optimizing internal flow organization, reducing flow dead zones, expanding the strong heat transfer area, improving heat transfer efficiency, and ultimately enhancing the uniformity and reliability of film cooling. It effectively solves the problem of rapid cooling efficiency decay in the downstream region of existing double-walled cooling structures due to uneven film distribution.

[0050] As an optional implementation, the aspect ratio of the air inlet 1 is 1.5-2.5.

[0051] The air inlet 1 has a racetrack-shaped structure with a length-to-width ratio preferably between 1.5 and 2.5. Its span area is more than 30% larger than that of a traditional circular hole, and the inlet edge adopts a smooth transition design. This gives the cooling gas jet a wider flow dimension and more stable flow characteristics when it enters the cooling chamber, effectively reducing flow separation at the inlet.

[0052] As an optional implementation, the turbulence assembly includes a first turbulence part and a second turbulence part arranged sequentially along the direction of the cold gas flow channel, and the first turbulence part and the second turbulence part are fixed in the cooling cavity.

[0053] The cooling air flows through the first turbulence section and the second turbulence section in sequence, and the heat transfer is enhanced and the airflow is evenly distributed through the turbulence.

[0054] As an optional implementation, the first turbulence section includes a plurality of first turbulence columns 2, and a first turbulence channel is formed between the plurality of first turbulence columns 2. The air inlet end of the first turbulence channel is connected to the air outlet end of the air inlet 1, and the air outlet end of the first turbulence channel is connected to the air inlet end of the second turbulence section.

[0055] As an optional implementation, the multiple first turbulence columns 2 are arranged in two rows;

[0056] The number of first spoiler columns 2 arranged near the air intake 1 is one less than the number of first spoiler columns 2 arranged away from the air intake 1;

[0057] The first spoiler column 2 in the front row is located between the two corresponding first spoiler columns 2 in the rear row;

[0058] The gap between the first turbulence pillars 2 forms the first turbulence channel.

[0059] Cooling gas exits through the inlet 1 and impacts the target surface 5 before diffusing back into the first turbulence channel formed by a series of staggered first turbulence columns 2. Specifically, the two rows of first turbulence columns 2 are staggered, with fewer columns in the front row than in the back row, and each column in the front row is directly opposite the gap between two adjacent columns in the back row. This arrangement allows the airflow to be fully divided, disturbed, and mixed as it passes through the first turbulence channel, effectively enhancing the convective heat transfer intensity between the airflow and the wall and turbulence columns, and making the airflow distribution more uniform, thus preparing the flow for subsequent entry into the second turbulence section.

[0060] As an optional implementation, the second turbulence section includes a plurality of second turbulence columns 3, and a second turbulence channel is formed between the plurality of second turbulence columns 3. The air inlet end of the second turbulence channel is connected to the air outlet end of the first turbulence channel, and the air outlet end of the second turbulence channel is connected to the cold air outlet 4.

[0061] As an optional implementation, multiple second spoiler columns 3 are arranged in a row;

[0062] The second turbulence column 3 is either a first teardrop-shaped structure or a second teardrop-shaped structure;

[0063] In the multiple second turbulence columns 3 in the same row, the first teardrop-shaped structure and the second teardrop-shaped structure are arranged alternately;

[0064] The second teardrop-shaped structure of the second baffle column 3 is set in a one-to-one correspondence with a row of first baffle columns 2 set near the air inlet 1.

[0065] The gap between the second turbulence columns 3 forms a second turbulence channel.

[0066] After passing through the first turbulence channel, the airflow enters the second turbulence channel formed by a row of second turbulence columns 3, wherein the first teardrop-shaped and second teardrop-shaped structures are arranged alternately, and the second teardrop-shaped structure of the second turbulence column 3 corresponds to the first turbulence column 2 in the front row. This design further turbulents the airflow and guides it to flow evenly into the cold air outlet 4, thereby enhancing the air film coverage effect.

[0067] As an optional implementation, the cold air outlet 4 and the impact bottom surface 6 are connected by a cold air outlet slit, the cold air outlet slit is inclined, and the angle between the cold air outlet slit and the cooling cavity is an obtuse angle.

[0068] Cooling air is discharged through a cold air outlet slit, which is connected to the impact bottom surface 6 at an obtuse angle, effectively guiding the airflow to cover the downstream area and enhancing the air film cooling effect.

[0069] As an optional implementation, the air inlet end of the cold air outlet slit smoothly transitions to the impact bottom surface 6.

[0070] As an alternative implementation, the edge of the air inlet 1 smoothly transitions to the impact bottom surface 6.

[0071] This device extends the area of ​​the wing-shaped high-heat-transfer zone on the bottom surface of the runway impact hole structure. It employs staggered, irregularly shaped baffles, connecting the outlets of these baffles to the cold air outlet. The wall-mounted cooling airflow impacts the target surface through inlet 1, diffuses within the double-walled structure, and cools the blade interior through the baffles, ensuring uniform airflow distribution. The cooling air then forms a film cooling effect on the blade surface through the outlet slot. The runway impact hole structure has an aspect ratio of 1.5-2.5, with a spanwise area more than 30% larger than traditional circular holes. This design helps improve flow distribution and reduce dead zones. The inlet edge of the impact hole features a smooth transition design to reduce flow separation and improve flow stability. An optimized spacing exists between the leading edge of the baffles and the outlet edge of the impact hole to enhance heat transfer.

[0072] In one specific embodiment, cool air from the internal passage of the turbine blade enters through the inlet, impacts the bottom surface 6 and the impact target surface 5, and diffuses within the double-walled structure. Due to insufficient space, the cool air deflects back and makes a secondary impact on the bottom surface, thus forming a "wing-shaped" heat transfer enhancement zone. The cool air flows through the first turbulence column 2 and the second turbulence column 3, and finally flows to the blade surface through the cool air outlet 4, forming film cooling. Due to the presence of the inlet 1, the cool air distribution is more uniform. The staggered arrangement of the first turbulence columns 2 better cools the interior of the blade. The teardrop-shaped turbulence column outlets are connected to the cool air outlet slits, which are designed with an obtuse angle to enhance the cool air coverage effect in the downstream section.

[0073] In this embodiment, the diameter of the air inlet 1 is 1.3 mm, the fill ratio of the turbulence column is 29.95%, the outlet expansion angle of the exhaust turbulence column is 10.5°, the exhaust slit width is 0.5 mm, and the slit flow direction inclination angle is 35°. To ensure comparability of results, the flow conditions of the two double-walled structures are completely identical, the area of ​​the impact holes is identical, and the geometric difference lies only in the type of impact holes.

[0074] A crescent-shaped low-heat-transfer zone exists between the core region of the impinging jet and the upstream wall of the laminate cavity and the leading edge wall of the downstream adjacent turbulence column. Between the first row of turbulence columns and the impingement hole, an eye-shaped low-heat-transfer zone exists on the bottom surface of the impingement jet. The wing-shaped high-heat-transfer region on the bottom surface of the runway hole structure is even longer, and the eye-shaped low-heat-transfer zone still exists. Compared with the basic structure, the heat transfer characteristics at the impingement stagnation point of the runway hole structure target surface show a tendency of "separation," with high heat transfer on both sides and lower heat transfer in the center. Compared with the basic structure, the runway hole structure target surface still has a flow dead zone, although the range of the flow dead zone is reduced due to the extension of the runway hole to both sides.

[0075] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "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, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0076] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A double-walled cooling structure for a racetrack-shaped impact hole, characterized in that, include: A cooling chamber is provided inside the turbine guide vane, wherein an air inlet (1), a turbulence assembly and a cold air outlet (4) are arranged sequentially along the direction of cold air flow. The cooling chamber includes two opposing walls, one of which is the impact target surface (5) and the other is the impact bottom surface (6). The air inlet (1) is opened on the impact bottom surface (6). After the cooling gas enters through the air inlet (1), it impacts the impact target surface (5) and bounces back from the impact target surface (5) to the impact bottom surface (6), causing the cooling gas to diffuse in the cooling chamber. The cold air outlet (4) is located on the impact target surface (5); The air inlet (1) has a racetrack-shaped structure.

2. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 1, characterized in that: The aspect ratio of the air inlet (1) is 1.5-2.

5.

3. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 1, characterized in that: The turbulence assembly includes a first turbulence section and a second turbulence section arranged sequentially along the direction of the cold gas flow channel, and the first turbulence section and the second turbulence section are fixed inside the cooling cavity.

4. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 3, characterized in that: The first turbulence section includes a plurality of first turbulence columns (2), and a first turbulence channel is formed between the plurality of first turbulence columns (2). The air inlet end of the first turbulence channel is connected to the air outlet end of the air inlet (1), and the air outlet end of the first turbulence channel is connected to the air inlet end of the second turbulence section.

5. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 4, characterized in that: The first turbulence columns (2) are arranged in two rows; The number of the first deflector columns (2) arranged near the air intake (1) is one less than the number of the first deflector columns (2) arranged away from the air intake (1); The first spoiler column (2) in the front row is located between the two corresponding first spoiler columns (2) in the rear row; The gap between the first turbulence columns (2) forms the first turbulence channel.

6. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 4, characterized in that: The second turbulence section includes a plurality of second turbulence columns (3), and a second turbulence channel is formed between the plurality of second turbulence columns (3). The air inlet end of the second turbulence channel is connected to the air outlet end of the first turbulence channel, and the air outlet end of the second turbulence channel is connected to the cold air outlet (4).

7. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 6, characterized in that: Multiple second-stage turbulence columns (3) are arranged in a row; The second turbulence column (3) is a first teardrop-shaped structure or a second teardrop-shaped structure; In the multiple second-stage turbulence columns (3) in the same row, the first teardrop-shaped structure and the second teardrop-shaped structure are arranged at intervals; The second teardrop-shaped structure of the second baffle column (3) is arranged in a one-to-one correspondence with a row of the first baffle columns (2) arranged near the air inlet (1); The gap between the second turbulence columns (3) forms the second turbulence channel.

8. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 1, characterized in that: The cold air outlet (4) is connected to the impact bottom surface (6) through a cold air outlet slit. The cold air outlet slit is inclined and the angle between the cold air outlet slit and the cooling cavity is obtuse.

9. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 1, characterized in that: The air inlet end of the cold air outlet slit smoothly transitions to the impact bottom surface (6).

10. The double-walled cooling structure for a racetrack-shaped impact hole according to claim 1, characterized in that: The edge of the air inlet (1) smoothly transitions to the impact bottom surface (6).

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