A double-walled cooling structure with racetrack-shaped impact holes and slits and its application.

Abstract

This invention discloses a double-walled cooling structure with runway-shaped impact holes and slits, and its application, belonging to the field of aero-engine heat dissipation technology. The structure includes an impact plate, a film cooling plate, and multiple turbulence columns. The impact plate has at least one runway-shaped impact hole, enabling the impact jet to form a uniform heat transfer distribution in the stagnation region. The film cooling plate has at least one slit, which tangentially guides cooling air to the outer surface of the film cooling plate to form a film, effectively isolating the high-temperature main stream from the substrate. Multiple turbulence columns connect the impact plate and the film cooling plate, forming an internal cavity between them. The turbulence columns increase the heat transfer area and fluid turbulence to enhance internal heat transfer. Cooling air flows sequentially through the impact hole, the internal cavity, and the slits to cool the hot-end components. This structure achieves a comprehensive cooling effect of uniform and efficient impact cooling, enhanced internal heat transfer, and stable film coverage with low flow loss.

Description

Technical Field

[0001] This invention relates to the field of aero-engine heat dissipation technology, and in particular to a double-walled cooling structure with runway-shaped impact holes and slits and its application. Background Technology

[0002] As core components of aero-engines, turbine blades and other hot-end components directly withstand the scouring of high-temperature exhaust gases, and their cooling performance has a significant impact on the overall performance and lifespan of the engine. Continuously increasing the turbine inlet temperature is one of the most effective technical approaches to improve engine thermal efficiency and thrust. Statistics show that approximately 60% of aero-engine failures occur in hot-end components; therefore, developing efficient and reliable cooling technologies has become crucial for the development of high-performance engines.

[0003] In the current cooling design of hot-end components, the double-wall cooling structure with "impact + internal turbulence + film cooling hole" configuration has gradually become the mainstream solution. Its typical working method is as follows: circular impact holes are arranged on the impact plate to form impact cooling on the inner surface of the film cooling plate; turbulence columns are set between the impact plate and the film cooling plate to enhance internal heat transfer; and film cooling holes are opened on the film cooling plate to achieve external film cooling. However, the above structure still has many shortcomings in practical applications: (1) the circular impact holes have large flow losses under high cold air flow conditions, and the heat transfer in the impact stagnation area is too strong, which can easily lead to excessive local temperature gradient; (2) the traditional circular film cooling holes are prone to film detachment from the wall under high blowing ratio conditions, which weakens the cooling effect; (3) the existing impact duct structure is difficult to achieve fine control of cold air flow in different areas; (4) the overall cooling efficiency is limited and it is difficult to meet the cooling capacity requirements of future high-performance engines for hot-end components.

[0004] Therefore, there is an urgent need to propose a novel double-walled cooling structure to overcome the above-mentioned defects, achieve low flow loss, high heat transfer efficiency and regional adjustability of cooling flow, and provide a better solution for the cooling design of hot-end components of aero-engines. Summary of the Invention

[0005] The purpose of this invention is to provide a double-walled cooling structure with runway-shaped impact holes and slits and its application. Through integrated design, it achieves low flow loss, high heat transfer efficiency, and independent control of each cooling unit. It aims to solve the above-mentioned problems, achieve strong cooling effect with low loss, make up for the shortcomings of existing cooling designs, provide guidance for the engineering design of turbine blade cooling structures, and improve the reliability and life of hot-end components of aero-engines.

[0006] To achieve the above objectives, the present invention provides the following solution: a double-walled cooling structure with racetrack-shaped impact holes and slits, comprising: an impact plate having at least one racetrack-shaped impact hole; a film cooling plate having at least one slit that tangentially guides cooling air to the outer surface of the film cooling plate to form a film; and multiple turbulence columns connected between the impact plate and the film cooling plate, forming an internal cavity between the impact plate and the film cooling plate; wherein cooling air flows sequentially through the impact holes, the internal cavity, and the slits to achieve cooling of the hot-end components.

[0007] Optionally, the turbulence columns are arranged in an array in the internal cavity, which increases the heat exchange area, increases the fluid turbulence to enhance internal heat exchange, and serves as a support element to withstand mechanical loads.

[0008] Optionally, the impact hole is composed of semicircular portions at both ends and a middle rectangular portion connecting the two semicircles, so as to form a uniform heat transfer distribution in the impact stagnation point region.

[0009] Optionally, the diameter of the round end of the impact hole D 2 and runway length L The flow resistance of the cooling air flowing through the double-walled cooling structure is controlled by independently adjusting the temperature load of the area.

[0010] Optionally, the tilt angle of the slit α seam width W 1 and seam height S Adjustments should be made according to actual working conditions to control the adhesion and coverage of the air film.

[0011] Optionally, the double-walled cooling structure has a fill ratio γ The calculation formula is as follows: in, n 2 represents the number of turbulence columns. D 1 represents the diameter of the turbulence column. W 1 represents the width of the narrow slit. W 2 represents the length of the internal flow channel; The fill ratio can be adjusted by changing the number or diameter of the baffle columns. γ This is to change the heat exchange area and flow resistance of the double-walled cooling structure.

[0012] Optionally, the hydraulic diameter of the impact hole D The calculation formula is: in, D2 represents the diameter of the round end of the impact hole. L This refers to the length of the impact hole runway.

[0013] Optionally, the double-walled cooling structure has a flow loss coefficient for quantifying flow losses. ξ The calculation formula is as follows: in, m c and m g These are the mass flow rates of the main airflow for cold air and high-temperature air, respectively. P t,in and P t,out These are the total cold air pressures at the inlet of the impact hole and the outlet of the slit, respectively. ρ g and U g These represent the density and velocity of the high-temperature mainstream, respectively.

[0014] The present invention also provides an application of a double-wall cooling structure in aero-engine turbine blades, specifically: a plurality of double-wall cooling units are covered on the outer wall of the turbine blade, wherein the double-wall cooling unit is a double-wall cooling structure with runway-shaped impact holes and slits as described in any of the above claims.

[0015] Furthermore, multiple double-walled cooling units are arranged side-by-side to form a cooling array on the outer wall of the turbine blade. Cooling air from the compressor enters the cold air channel through the turbine disk and the tenon of the turbine blade, and then flows sequentially through the impact hole, the turbulence column, and the slit. The high-temperature mainstream flowing out of the combustion chamber washes over the surface of the turbine blade along the mainstream channel. The cooling air exiting from the slit forms an air film that isolates the high-temperature mainstream from the substrate of the turbine blade, thereby achieving thermal protection of the turbine blade in a high-temperature environment.

[0016] Compared with the prior art, the present invention discloses at least the following beneficial effects: The present invention provides a double-walled cooling structure with racetrack-shaped impact holes and slits. Cooling air first enters the internal cavity through the racetrack-shaped impact holes. Due to the racetrack-shaped structure, compared to traditional circular holes, the impact jet can form a more uniform heat transfer distribution in the stagnation area, avoiding temperature gradient problems caused by excessive local heat transfer. Subsequently, the cooling air flows through the internal cavity between the impact plate and the film gas plate. Multiple turbulence columns installed in this cavity not only act as supporting elements to withstand mechanical loads but also significantly increase the heat transfer area and enhance fluid turbulence, thereby strengthening the internal heat transfer effect. Finally, the cooling air is tangentially led out to the outer surface of the film gas plate through the slits, forming a continuous and well-adhered wall-mounted film gas, effectively isolating the high-temperature mainstream from the substrate. Thus, this structure achieves a comprehensive cooling effect of uniform and efficient impact cooling, enhanced internal heat transfer, and stable film gas coverage while achieving low flow loss. Attached Figure Description

[0017] 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 introduced 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.

[0018] Figure 1 A schematic diagram of a double-walled cooling structure with racetrack-shaped impact holes and slits provided in an embodiment of the present invention; Figure 2 This is an overall sectional view of an embodiment of the present invention; Figure 3 for Figure 2 Sectional view at point AA; Figure 4 This is an example diagram illustrating the application of embodiments of the present invention; Figure 5 This is a comparison diagram of the convective heat transfer coefficient distribution between the runway hole and the traditional circular hole in this embodiment of the invention; Figure 6 This is a schematic diagram of parameters according to an embodiment of the present invention.

[0019] Reference numerals: 1. Double-walled cooling unit; 100. Heat exchange interest area; 101. Impact hole; 102. Baffle column; 103. Slit; 2. Main flow channel; 3. Cold air channel; 4. Turbine blade unit cooling structure; 5. Turbine blade; 6. Turbine disk; 7. Combustion chamber; 8. Compressor. Detailed Implementation

[0020] 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.

[0021] 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.

[0022] Reference Figures 1 to 6 As shown, this embodiment provides a double-walled cooling structure with racetrack-shaped impact holes and slits. This double-walled cooling structure is presented as an independent cooling unit. For ease of description, a single double-walled cooling structure will be defined as a double-walled cooling unit 1. Multiple double-walled cooling units 1 can be arranged side-by-side to jointly constitute the cooling system for hot-end components such as turbine blades 5. Each double-walled cooling unit 1 integrates three efficient cooling mechanisms: impact cooling, turbulence-enhanced heat transfer, and slit film cooling. Furthermore, the cooling gases between each unit are independent and do not interfere with each other, providing a structural basis for precise control of the cold air flow in different regions of the blade.

[0023] In this embodiment, as Figure 1 , Figure 2 and Figure 3 As shown, the double-walled cooling unit 1 mainly includes an impact hole 101, a turbulence column 102, and a slit 103. In practical applications, this cooling structure also involves a cold air passage 3 and a main flow passage 2. Cooling air from the compressor 8 flows through the turbine disk 6 and the tenon of the turbine blade 5 into the cold air passage 3 inside the blade. The cooling air first enters the internal cavity of the double-walled cooling unit 1 through the impact hole 101 opened on the impact plate, forming a high-speed impact jet, which locally enhances heat transfer at the impact stagnation point and the surrounding area, thereby effectively removing heat from the inner wall surface of the double-walled cooling unit 1 and reducing its inner surface temperature.

[0024] In practical applications, such as Figure 4 As shown, multiple double-walled cooling units 1 are arranged side by side on the surface of the turbine blade unit cooling structure 4, forming a cooling array covering the outer wall of the blade. Cooling air from the compressor 8 enters the cold air channel 3 through the turbine disk 6 and the blade tenon, and then flows through the impact hole 101, the turbulence column 102 and the slit 103 in sequence to complete internal heat exchange and form a gas film covering. The high-temperature mainstream flowing out of the combustion chamber 7 washes the blade surface along the mainstream channel 2, and the cooling gas film isolates the high-temperature mainstream from the blade substrate, thereby achieving effective thermal protection for the turbine blade 5 in the high-temperature environment at the outlet of the combustion chamber 7.

[0025] In one specific embodiment, such as Figure 1 , Figure 4 and Figure 6 As shown, the impact hole 101 is constructed in the shape of a running track. This running track-shaped impact hole 101 consists of semicircular portions at both ends and a central rectangular portion connecting the two semicircles, its overall shape resembling a running track in an athletics stadium. The diameter of the circular end of the impact hole 101... D 2 and runway length L These are the core parameters designed based on cooling requirements.

[0026] In practical applications, the number and geometry of the impact holes 101 can be independently configured for each double-walled cooling unit 1 according to its specific location on the turbine blade 5 and the temperature load it bears. For example, for high-temperature and high-load areas such as the blade leading edge, the runway length can be shortened. L Alternatively, a strategy of increasing the number of impact holes 101 can be employed to increase the velocity and rigidity of the impact jet, thereby enhancing the heat transfer effect in the impact stagnation region. Conversely, for areas with relatively low heat loads, such as the middle or trailing edge of the blade, the runway length of the impact holes 101 can be appropriately increased. L While meeting basic heat exchange requirements, it effectively reduces the flow resistance of cooling air through the unit, achieving efficient utilization of cold air.

[0027] Based on the above embodiments, further, such as Figure 1 , Figure 4 and Figure 6 As shown, an array of turbulence columns 102 is arranged in the internal cavity of the double-walled cooling unit 1, between the impact plate and the air film plate. Figure 1 The double-walled cooling unit 1 shown has a total of 20 circular baffle columns 102 arranged in 4 rows × 5 columns. The baffle columns 102 are mainly used to achieve dual functions.

[0028] Firstly, it is used to enhance internal heat transfer. Compared with a cavity structure without turbulence columns, the setting of turbulence columns 102 significantly increases the heat transfer area between the solid and the fluid. At the same time, when the cooling air flows through the turbulence columns 102, it will periodically generate flow separation and reattachment, which greatly increases the turbulence of the fluid, thereby significantly improving the convective heat transfer effect inside the entire cooling structure.

[0029] Secondly, the turbulence column 102 also serves as a key supporting element of the double-walled structure, bearing mechanical loads and enhancing the mechanical strength and rigidity of the cooling unit. For thin-walled structures like turbine blades 5 (each layer typically has a wall thickness of about 0.7 mm), if the space between the two layers is hollow, structural failures such as deformation and cracking are easily caused under the enormous centrifugal force generated by high temperature and high speed.

[0030] As can be seen from the above structure, this double-walled cooling structure significantly enhances the overall strength of the structure by setting multiple rows of baffle columns 102 and organizing them in the form of cooling units. In practical engineering applications, the shape (e.g., circular, elliptical, teardrop-shaped) and diameter of the baffle columns 102 are... D 1. Arrangement method (e.g., sequential, cross-arrangement) and quantity n Both can be flexibly adjusted according to the flow resistance requirements of the target area and the need for enhanced local heat transfer.

[0031] Furthermore, such as Figure 1 , Figure 4 and Figure 6 As shown, the double-walled cooling unit 1 also includes a slit 103. This slit 103 replaces the traditional film cooling hole, serving as an outlet for cooling air to flow out of the double-walled internal cavity and cover the outer surface of the blade. Its main function is to guide the cooling air, which has already undergone heat exchange within the double-walled structure, to the outer surface of the blade in a near-tangential manner, forming a continuous, stable, and well-adhered wall-mounted cooling film. This cooling film effectively physically isolates the high-temperature mainstream from the blade wall, preventing direct contact between the high-temperature mainstream and the blade substrate material, thereby achieving highly efficient thermal protection of the blade's outer wall surface.

[0032] In this structure, the geometric parameters of slit 103 include slit width W 1. Seam height S and the tilt angle relative to the blade surface α All of these can be optimized and adjusted according to the actual service conditions of the blades. For example, to achieve better film cooling coverage and cooling effect, the slit width can be appropriately reduced. W 1 and tilt angle α This allows for a cool air jet that is closer to the wall surface. Of course, this superior film cooling effect is sometimes accompanied by increased processing complexity and increased internal flow resistance, so a comprehensive trade-off needs to be made in the engineering design.

[0033] In yet another specific embodiment, the double-walled cooling structure provided by the present invention achieves a highly parameterized design. For example... Figure 4 As shown, the performance of the entire double-walled cooling unit 1 can be defined and predicted through a series of well-defined geometric and flow parameters. These parameters mainly include: slit structure parameters, such as slit width. W 1. Seam height S and tilt angle α Impact hole structural parameters, such as the number of impact holes. n 1. Diameter of the round end of the impact hole D 2. Impact hole runway length L ; structural parameters of the baffle columns, such as the number of baffle columns n 2. Diameter of the turbulence column D1; and the length of the internal flow channel of the double-walled structure. W 2. Based on the above parameters, the fill ratio of the double-walled cooling structure can be defined. γ The calculation formula is as follows: Meanwhile, the hydraulic diameter of the impact hole D It can be calculated using the following formula: Based on the above embodiments, further, by changing the number of turbulence columns... n 2 or diameter D 1. The filling ratio of the double-wall structure can be adjusted independently. γ By changing the diameter of the round end of the impact hole D 2 or runway length L The hydraulic diameter of the impact hole can be adjusted independently. D This allows for the adjustment of the flow resistance of the cooling unit. Since the cooling structure of this invention exists as independent units, the change in the flow resistance of each unit, under a fixed supply pressure, affects the mass flow rate of the cooling gas passing through that unit. m c This will also lead to changes. This characteristic allows designers to independently design the geometric parameters of each cooling unit based on the heat load distribution in different areas of the turbine blade surface, thereby achieving precise control of the cooling airflow in different areas. This modular and parameterized design method fundamentally changes the traditional cooling design model that relies on "trial and error based on experience," providing a solid theoretical basis and implementation path for the refined and customized cooling design of aero-engine turbine blades.

[0034] To quantify the flow loss and heat transfer performance of the double-walled cooling unit 1, this invention also defines corresponding performance evaluation parameters. For example... Figure 4 As shown, the flow loss of the double-walled cooling unit 1 is defined. ξ The calculation formula is: in, m c and m g These are the mass flow rates of the cold air and the high-temperature mainstream in the double-walled cooling unit 1, respectively. P t,in and P t,out These are the total cold air pressures at the inlet of impact hole 101 and the outlet of slit 103, respectively. ρ g and U g These represent the density and velocity of the high-temperature mainstream, respectively. On the other hand, the convective heat transfer coefficient is used.h The heat exchange effect of the double-walled cooling unit 1 is defined by the following formula: in, q For heat flux density, Δ T This represents the characteristic temperature difference between the cold air and the wall. The area-average convective heat transfer coefficient for a specific heat transfer interest region 100 (e.g., the impingement stagnation zone or the turbulence column region) can be calculated using the following integral formula: in, X , Y The horizontal and vertical coordinates of the plane containing the region of interest are defined. Through the above parameterized definitions and calculation formulas, the overall performance of the cooling structure of this invention can be accurately evaluated and predicted.

[0035] Figure 3 This paper presents a comparison of the convective heat transfer coefficient distribution contour maps of the racetrack-shaped impact orifice proposed in this invention and the traditional circular impact orifice at an impact Reynolds number of 40,000. The figures clearly show that the racetrack-shaped impact orifice not only maintains enhanced heat transfer capacity in the impact stagnation region, but more importantly, its high heat transfer area is more uniformly distributed, effectively avoiding the problem of excessive local temperature gradients caused by the circular impact orifice. Combined with… Figure 5 The diagram showing the distribution of convective heat transfer coefficients demonstrates that the cooling structure provided by this invention achieves superior and more uniform heat transfer effects while maintaining low flow loss compared to existing technologies.

[0036] Compared with existing technologies, the double-wall cooling structure with racetrack-shaped impact holes and slits provided by this invention effectively solves the technical problems of large flow losses and excessive local temperature gradients caused by excessive heat transfer in the impact stagnation area under high airflow conditions. This is achieved by replacing traditional circular impact holes with racetrack-shaped ones. Simultaneously, replacing traditional circular film cooling holes with inclined slits avoids the film detachment phenomenon that easily occurs under high airflow ratios, resulting in a continuous, stable, and well-adhered film cooling system that adheres to the wall, significantly improving film cooling efficiency. Furthermore, this invention achieves highly parametric design by dividing the overall cooling structure into multiple independently designable cooling units, allowing for precise calculation of cooling performance and flow characteristics. This modular design allows designers to independently adjust key parameters such as the fill ratio and hydraulic diameter of the impact holes for each cooling unit based on the temperature load distribution in different areas of the hot-end component, thus overcoming the drawback of traditional double-wall structures that cannot achieve fine-tuning of airflow in different areas. Ultimately, this invention achieves a more uniform temperature field distribution and higher overall cooling efficiency, providing strong technical support for improving the reliability and service life of hot-end components of aero engines.

[0037] 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.

[0038] 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 with racetrack-shaped impact holes and slits, characterized in that, include: An impact plate having at least one racetrack-shaped impact hole (101). An air film plate has at least one slit (103) thereon, the slit (103) tangentially guiding cooling air to the outer surface of the air film plate to form an air film; Multiple turbulence columns (102) are connected between the impact plate and the air film plate, forming an internal cavity between the impact plate and the air film plate; Cooling air flows sequentially through the impact hole (101), the internal cavity, and the slit (103) to cool the hot-end component.

2. The double-walled cooling structure with racetrack-shaped impact holes and slits according to claim 1, characterized in that, The turbulence columns (102) are arranged in an array in the internal cavity, which increases the heat exchange area, increases the fluid turbulence to enhance internal heat exchange, and serves as a support element to bear mechanical loads.

3. The double-walled cooling structure with racetrack-shaped impact holes and slits according to claim 1 or 2, characterized in that, The impact hole (101) is composed of semicircular portions at both ends and a middle rectangular portion connecting the two semicircles, so as to form a uniform heat transfer distribution in the impact stagnation point area.

4. The double-walled cooling structure with racetrack-shaped impact holes and slits according to claim 3, characterized in that, The diameter of the round end of the impact hole (101) D 2 and runway length L The flow resistance of the cooling air flowing through the double-walled cooling structure is controlled by independently adjusting the temperature load of the area.

5. The double-walled cooling structure with racetrack-shaped impact holes and slits according to claim 4, characterized in that, The tilt angle of the slit (103) α seam width W 1 and seam height S Adjustments should be made according to actual working conditions to control the adhesion and coverage of the air film.

6. The double-walled cooling structure with racetrack-shaped impact holes and slits according to claim 5, characterized in that, The double-walled cooling structure has a filling ratio. γ The calculation formula is as follows: in, n 2 represents the number of turbulence columns. D 1 represents the diameter of the turbulence column. W 1 represents the width of the narrow slit. W 2 represents the length of the internal flow channel; The fill ratio can be adjusted by changing the number of the baffle columns (102) or the diameter of the baffle columns (102). γ This is to change the heat exchange area and flow resistance of the double-walled cooling structure.

7. The double-walled cooling structure with racetrack-shaped impact holes and slits according to claim 1 or 6, characterized in that, The hydraulic diameter of the impact hole (101) D The calculation formula is: in, D 2 represents the diameter of the round end of the impact hole. L This refers to the length of the impact hole runway.

8. The double-walled cooling structure with racetrack-shaped impact holes and slits according to claim 1, characterized in that, The double-walled cooling structure has a flow loss coefficient for quantifying flow losses. ξ The calculation formula is as follows: in, m c and m g These are the mass flow rates of the main stream air supply for cold air and high temperature air, respectively. P t,in and P t,out These are the total cold air pressures at the inlet of the impact hole and the outlet of the slit, respectively. ρ g and U g These represent the density and velocity of the high-temperature mainstream, respectively.

9. The application of a double-walled cooling structure in aero-engine turbine blades, characterized in that, Multiple double-wall cooling units (1) are covered on the outer wall of the turbine blade (5), and the double-wall cooling unit (1) is a double-wall cooling structure with racetrack-shaped impact holes and slits as described in any one of claims 1 to 8.

10. The application of the double-walled cooling structure according to claim 9 in aero-engine turbine blades, characterized in that, Multiple double-walled cooling units (1) are arranged side by side to form a cooling array on the outer wall of the turbine blade (5). Cooling air from the compressor (8) enters the cold air passage (3) through the turbine disk (6) and the tenon of the turbine blade (5), and then flows through the impact hole (101), the turbulence column (102) and the slit (103) in sequence. The high-temperature mainstream flowing out of the combustion chamber (7) washes the surface of the turbine blade (5) along the mainstream passage (2). The cooling air led out from the slit (103) forms an air film to isolate the high-temperature mainstream from the substrate of the turbine blade (5) so as to achieve thermal protection of the turbine blade (5) in a high-temperature environment.

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