A porous material trailing edge structure with built-in cooling passages and a turbine guide vane

Abstract

The application provides a porous material trailing edge structure with built-in cooling channels and a turbine guide vane, and belongs to the field of gas turbine turbine blade cooling. The structure is composed of a sintered porous material and is provided with multistage Y-shaped bifurcated cooling channels in the interior, which extend from the front part of the trailing edge to the pressure surface, the suction surface and the tail part, and the number of the cooling channels extending to the suction surface is more than that extending to the pressure surface; the structure of the cooling channels is cylindrical, and the diameter of the nth stage main pipe and the diameter of the branch pipe satisfy. The coolant realizes sweating cooling through the porous medium penetration and forms a gas film cooling by flowing in the channels, and the two cooling modes are combined, so that the coolant utilization efficiency is significantly improved, and the consumption and the pressure loss are reduced. The Y-shaped bifurcated design makes the coolant form a complex flow path in the interior of the trailing edge, and uniformly covers the suction surface and the pressure surface. The structure is simple, is coordinated with the whole vane, simplifies the trailing edge design, and improves the process and the structural strength.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine guide vane cooling technology, specifically relating to a porous material trailing edge structure with built-in cooling channels and a gas turbine guide vane including the cooling structure. Background Technology

[0002] In gas turbine engines, the turbine, as a core component, has a decisive impact on the overall engine performance. Increasing the inlet gas temperature can significantly improve the engine's thrust characteristics and cycle efficiency. However, current gas temperatures far exceed the heat resistance limit of the super-heat-resistant alloy materials used in turbine guide vanes. To ensure sufficient safety, reliability, and service life of the turbine guide vanes in high-temperature operating environments, efficient cooling measures are essential.

[0003] The trailing edge of a turbine guide vane is a critical component for cooling because its structural integrity directly affects the aerodynamic performance and lifespan reliability of the blade, and both the pressure and suction surfaces bear extremely high thermal loads. Efficient cooling is essential to prevent the trailing edge structure from being eroded and damaged by high-temperature combustion gases during engine service. Traditional turbine guide vane trailing edge cooling structures mainly include full-slot cooling structures, discrete orifice cooling structures, and semi-slotted cooling structures.

[0004] In the existing technology, many patents have studied and improved the cooling structure of turbine guide vane trailing edge. For example, patent CN202311350044.2 proposes to achieve cooling by arranging circular holes on the pressure surface of the blade trailing edge and expanding trapezoidal holes on the suction surface; patent CN202410632231.8 enhances the heat transfer effect of cooling airflow by setting turbulence columns and oblique ribs on the inner surface of the blade trailing edge. However, these technologies still have the following limitations: First, the cooling effect of the trailing edge cooling structure on the suction surface is not good. Existing cooling structures mostly focus on cooling the pressure surface, while the suction surface mainly relies on wall heat conduction for cooling. Compared with convection cooling, the cooling effect is significantly insufficient, resulting in a large temperature difference between the trailing edge suction surface and the pressure surface, uneven temperature distribution, increased thermal stress, and affecting blade performance. Second, the trailing edge geometry is thin and small, and the internal cooling channel is narrow, which requires extremely high precision in processing technology. Moreover, when arranging complex structures, it is difficult to avoid damage to the overall blade structure. At the same time, complex turbulence structures will also reduce the structural strength of the blade and increase the risk of failure. Third, traditional cooling structures will increase flow resistance and flow loss, which will lead to an increase in coolant consumption. Summary of the Invention

[0005] The purpose of this invention is to address the problems of low cooling efficiency of the suction surface in the trailing edge cooling of gas turbine guide vanes, complex structures that reduce blade structural strength, high pressure loss, and high coolant consumption in existing technologies. This invention provides a porous material trailing edge structure with built-in cooling channels and a gas turbine guide vane incorporating this cooling structure. This invention utilizes porous materials with built-in cooling channels in the trailing edge structure, combining film cooling and evaporative cooling. Coolant can permeate through the porous medium, flowing and absorbing heat within the cooling channels, improving the cooling effect on the blade's suction surface, reducing localized high-temperature zones, enhancing thermal stability, reducing coolant consumption and pressure loss, and simultaneously increasing blade structural strength.

[0006] To achieve the above objectives, the technical solution provided by this invention is:

[0007] On the one hand, a porous material trailing edge structure with built-in cooling channels is provided. The sintered porous material is used to form the trailing edge of the gas turbine guide vane. Cooling channels for the flow of coolant are provided inside the sintered porous material.

[0008] The cooling channels have a multi-level Y-shaped bifurcation structure, extending from the front of the tail edge to the pressure surface, suction surface, and tail. The number of cooling channels extending to the suction surface is greater than the number extending to the pressure surface. Each Y-shaped bifurcation structure in each level forms a three-way structure at the bifurcation node and branches into two branches from a single main pipe along the coolant flow direction. The branch pipes of each level of Y-shaped bifurcation structure serve as the main pipes of the next level of Y-shaped bifurcation structure.

[0009] The cooling channel has a cylindrical structure; the first cooling channel... The diameter of the main pipe of the Y-type bifurcation structure is The diameter of the branch pipe is , No. The diameter of the main pipe of the Y-shaped bifurcation structure is also... It satisfies the following relationship: .

[0010] Furthermore, the number of cooling channels extending to the suction surface The number of cooling channels extending to the pressure surface The relationship between them is: .

[0011] Furthermore, the diameter of the branch pipe of the Y-shaped bifurcation structure at the final stage of the cooling channel is equal to the inherent pore diameter of the porous material.

[0012] Furthermore, the diameter of the main pipe of the first-stage Y-shaped branch structure of the cooling channel... The total number of levels of the Y-shaped bifurcation structure and the inherent pore diameter of porous materials Constraints: .

[0013] On the other hand, a gas turbine guide vane is provided, including a blade body and a porous material trailing edge structure with built-in cooling channels. The two ends of the blade body and the trailing edge structure are respectively fixed to the end wall of the upper guide vane and the end wall of the lower guide vane. Sealing plates are provided at the relative positions of the trailing edge structure and the blade body on the pressure side and the suction side. The two ends of each sealing plate are respectively accommodated in the grooves at the relative positions of the blade body and the trailing edge structure. The sealing plates can be blown by the pressure generated by the flow of cold air to fit against the outer surface of the blade, thereby preventing the gas from intruding into the interior of the guide vane.

[0014] Furthermore, the gas turbine guide vane also includes multiple turbulence columns arranged along the blade spanwise on both the pressure side and the suction side. Two turbulence columns at corresponding positions on each side are fixed to the grooves in the blade body and trailing edge structure at both ends of the sealing sheet, so as to constrain the movement of the sealing sheet in the groove along the flow direction at both ends of the sealing sheet.

[0015] The advantages of this invention are:

[0016] 1. The porous material trailing edge structure with built-in cooling channels provided by this invention uses porous material with built-in cooling channels to form the trailing edge of a gas turbine guide vane. The cooling channels are multi-stage Y-shaped bifurcated structures extending from the front of the trailing edge to the pressure surface, suction surface, and tail of the trailing edge. The trailing edge structure of this invention is simple. When high-temperature heat flows onto the trailing edge, the coolant flows from the front of the trailing edge to the first-stage cooling channels, flowing and absorbing heat within the porous material. During the flow, the coolant achieves evaporative cooling through permeation of the porous medium and film cooling through flow within the cooling channels. This combination of cooling methods allows for efficient coolant utilization, reducing coolant consumption and pressure loss. Furthermore, by utilizing the Y-shaped bifurcated flow path, the coolant can form a more complex flow path within the trailing edge, thereby more uniformly covering the suction and pressure surfaces of the blade trailing edge.

[0017] 2. The cooling structure of the present invention is coordinated with the overall blade structure, which will not damage the aerodynamic performance of the blade, simplifies the design of the trailing edge structure of the gas turbine guide vane, reduces the processing difficulty, and enhances the structural strength of the blade.

[0018] 3. In this invention, the number of cooling channels arranged on the suction surface is greater than that on the pressure surface, which can ensure that the air film cooling efficiency on the suction surface side and the pressure surface side is balanced, effectively solving the problem of insufficient cooling on the suction surface in traditional cooling structures.

[0019] 4. Compared with existing gas turbine guide blades, the gas turbine guide blades provided by this invention adopt a porous material trailing edge structure with built-in cooling channels, which combines gas film cooling and evaporative cooling, improves the cooling effect of the blade suction surface, reduces local high temperature areas, reduces coolant consumption and pressure loss, and enhances the structural strength of the blade.

[0020] 5. The guide vane of the present invention is provided with sealing sheet structures on the pressure side and suction side respectively, which can prevent high-temperature gas from entering the interior of the guide vane, ensure the sealing environment and operational safety inside the vane, and improve the reliability of the vane.

[0021] 6. Through extensive numerical simulations and theoretical analysis, this invention optimizes the ratio of the branch pipe diameter to the main pipe diameter in each stage of the Y-shaped bifurcation structure to a specific range of 1 / 2 to 3 / 4. This range is particularly crucial for the uniform cooling of the turbine guide vane trailing edge: if the diameter ratio is less than 1 / 2, the branch pipe contracts excessively. According to the fluid dynamics principle that local resistance is inversely proportional to the fourth power of the pipe diameter, the flow resistance of the branch pipe at the far end of the suction side increases sharply, making it difficult for the coolant to reach the trailing edge. This results in a severe deterioration of the cooling effect on the suction side, a sharp increase in the temperature difference with the pressure side, and thermal stress concentration, threatening the safety of the blade. If the diameter ratio is greater than 3 / 4, the branch pipe contracts insufficiently, and the momentum effect of the coolant is significant at each bifurcation node. It is easy for the coolant to "short-circuit" and flow out along the near-end branch pipe, resulting in a shortage of coolant supply at the far end of the suction side, which also leads to local overheating. This invention strictly limits the diameter ratio to between 1 / 2 and 3 / 4, achieving matching and balanced distribution of coolant flow between the suction and pressure surfaces at the trailing edge. While maintaining a low channel pressure drop, it reduces the temperature difference between the suction and pressure surfaces, improves the film cooling efficiency of the suction surface, and effectively solves the technical problems of insufficient cooling of the suction surface and large temperature difference between the two sides in traditional trailing edge cooling structures. This significantly improves the thermal stability and service reliability of turbine guide vanes. Attached Figure Description

[0022] The above and / or other features and advantages of the present invention will become more readily understood from the following description with reference to the accompanying drawings, which are not drawn to scale and some features are enlarged or reduced to show details of specific parts.

[0023] Figure 1 This is an isometric view of the porous material trailing edge structure with built-in cooling channels and the blades of the present invention.

[0024] Figure 2 This is a partially enlarged view of the porous material trailing edge structure with built-in cooling channels of the present invention;

[0025] Figure 3 This is a partially enlarged view of the sealing sheet structure in the guide vane of the present invention;

[0026] Figure 4This is a flow diagram of the coolant in the porous material trailing edge structure with built-in cooling channels of the present invention.

[0027] Figure 5 The following is a simulation effect diagram of the present invention in an example: a comparison diagram of the air film cooling efficiency of the suction surface with and without the built-in Y-shaped bifurcated cooling channel;

[0028] Figure 6 The following is a simulation diagram of the invention in an example: a comparison of the air film cooling efficiency of the pressure surface with and without the built-in Y-shaped bifurcated cooling channel.

[0029] In the diagram: 1-blade body; 2-tail edge; 21-cooling channel inlet; 3-sealing plate structure; 4-suction surface; 5-pressure surface; 6-sealing plate; 7-air film pore; 8-turbulence column. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments thereof. It should be noted that the following detailed description of the present invention is for illustrative purposes only and is not intended to limit the scope of the invention.

[0031] It should be noted that, in the context of this invention, the terms “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “clockwise,” and “counterclockwise,” 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 invention 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 limiting this invention.

[0032] Furthermore, terms such as "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0033] This invention provides a high-efficiency cooling structure for the trailing edge made of porous material with built-in cooling channels. This solves the problems in the prior art, such as high temperature on the suction surface of the trailing edge, large temperature difference with the pressure surface, uneven temperature distribution, and increased thermal stress affecting blade performance. It also addresses the issues of complex trailing edge structures, large pressure losses, and large coolant consumption. The invention utilizes porous materials with built-in cooling channels in the trailing edge structure, combining film cooling and evaporative cooling to improve the cooling effect on the suction surface of the blade, reduce local high-temperature areas, enhance thermal stability, reduce coolant consumption and pressure loss, and simultaneously enhance the structural strength of the blade.

[0034] Reference Figure 1 and Figure 2In the porous material trailing edge structure with built-in cooling channels provided by the present invention, the trailing edge 2 of the gas turbine guide vane is formed by sintering porous material. The sintering porous material is provided with a cooling channel for the flow of coolant. The cooling channel can be connected to a coolant source, or the coolant can also enter from the surface of the porous material.

[0035] Porous materials can use metallic materials as the matrix to ensure good thermal conductivity and structural strength. In an exemplary embodiment, the porous material is formed by sintering nickel-based superalloy powder (such as Inconel 718).

[0036] The cooling channel features a multi-stage Y-shaped bifurcation structure, extending from the leading edge (cooling channel inlet 21) to the suction surface 4, pressure surface 5, and tail. Each Y-shaped bifurcation structure within each stage forms a three-way structure at the bifurcation node, branching into two branches along the coolant flow direction from a single main pipe. The branch pipes of each stage's Y-shaped bifurcation structure serve as the main pipe for the next stage's Y-shaped bifurcation structure. The cooling structure is designed in harmony with the overall blade structure, ensuring no disruption to the blade's aerodynamic performance.

[0037] According to the present invention, the structure of the cooling channel can be designed as a cylinder with Y-shaped bifurcation, similar to the bifurcation structure of blood vessels or tree branches. The flow channels of each layer are similar to a three-way structure. This design helps the coolant to be distributed more evenly throughout the entire trailing edge area, thereby improving cooling efficiency.

[0038] In each stage of the Y-shaped branch structure of the cooling channel, the inclination angles of the two branch pipes of each Y-shaped branch structure relative to the suction surface 4 or the pressure surface 5 can be different or the same. The extension lengths of the branch pipes can also be the same or different, and the cross-sectional dimensions of the branch pipes can also be the same or different. Similarly, the inclination angles, extension lengths, and cross-sectional dimensions of the main pipe of each Y-shaped branch structure in each stage of the cooling channel can also be different or the same.

[0039] In the illustrated embodiment, the first-stage Y-shaped bifurcation structure includes one Y-shaped bifurcation structure, but this is not limited to it; the number of bifurcation stages extending from the branch of the first-stage Y-shaped bifurcation structure can be different. The arrangement of the bifurcation structures is based on coordination with the overall blade structure and ensuring uniform cooling of the trailing edge region.

[0040] In a preferred embodiment, the number of cooling channels extending to the suction surface 4 is greater than the number of cooling channels extending to the pressure surface 5. Specifically, the number of cooling channels extending to the suction surface 4 is greater than the number of cooling channels extending to the pressure surface 5. The number of cooling channels extending to pressure surface 5 The relationship between them is This ensures that the cooling efficiency of the air film on both sides is balanced, effectively solving the problem of insufficient cooling of the suction surface in traditional cooling structures.

[0041] In addition, the first cooling channel The diameter of the main pipe of the Y-type bifurcation structure is The diameter of the branch pipe is , No. The diameter of the main pipe of the Y-shaped bifurcation structure is also... It satisfies the following relationship: That is, the ratio of the branch pipe diameter to the main pipe diameter. Within the range of 1 / 2 to 3 / 4. The selection of this diameter constraint relationship is of significant technical importance. In a bifurcation network, the ratio of the branch pipe diameter to the main pipe diameter (i.e., the diameter ratio) is crucial. It directly affects the flow resistance, velocity distribution, and heat exchange effect of the coolant in the channel.

[0042] The diameter of the branch pipes in the Y-shaped bifurcation structure at the very end of the cooling channel is similar to, and in particular equal to, the inherent pore diameter of the porous material.

[0043] The diameter of the main pipe of the first-stage Y-shaped branch structure of the cooling channel The total number of levels of the Y-shaped bifurcation structure and the inherent pore diameter of porous materials Constraints: .

[0044] It should be noted that the inherent pore diameter of the present invention The area of ​​the selected statistical cross-section was obtained by measuring a representative statistical cross-section of the porous material matrix. Due to porosity Obtain the total pore area The total perimeter of the pore boundaries was obtained by summing all the pore boundaries within the statistical region through microscopic image analysis. Substitute into the formula The calculation yielded the result.

[0045] In this invention, the trailing edge utilizes a porous material with built-in cooling channels. Coolant channels are designed within the porous material. As the coolant flows through the cooling channels, it uniformly absorbs the temperature of the porous material, thereby lowering its temperature. Furthermore, when the coolant absorbs heat and undergoes a phase change within the porous medium, the excellent convective heat transfer capability of the liquid coolant and the heat sinking effect of the latent heat of the phase change significantly enhance the cooling capacity and reduce coolant consumption.

[0046] After heat transfer through the porous medium via convection, the coolant permeates and mixes with the high-temperature mainstream, thickening the boundary layer on the solid wall surface and thus reducing the heat transferred from the high-temperature mainstream to the solid wall. After flowing out of the cooling channel, the coolant forms a cooling film on the hot surface of the porous material. This combination of evaporative cooling and film cooling achieves efficient coolant utilization and improves the reliability of the cooling system.

[0047] The cooling channels extend towards both the suction and pressure surfaces. By optimizing the distribution of the coolant, the cooling effect on the suction surface of the blades is improved, local high-temperature areas are reduced, and thermal stability is enhanced. This solves the problem of high temperature on the trailing edge suction surface and large temperature difference with the pressure surface in existing technologies.

[0048] Return to reference Figure 1 The present invention also provides a gas turbine guide vane, including a blade body 1 and a porous material trailing edge structure with built-in cooling channels. The blade body 1 and the trailing edge 2 are respectively fixed to the end wall of the upper guide vane and the end wall of the lower guide vane in the blade spanwise direction. A sealing sheet structure 3 is provided between the blade body 1 and the trailing edge structure.

[0049] In the sealing structure 3, sealing plates 6 are provided at the relative positions of the trailing edge 2 and the blade body 1 on the pressure and suction sides. These sealing plates are thin plates made of the same material as the blade body 1. The sealing plates 6 extend along the spanwise direction of the blade and are conformally designed to fit the blade structure. Each sealing plate 6 has its two ends, in the flow direction of the blade, respectively housed in grooves at the relative positions of the blade body 1 and the trailing edge 2. When cold air flows in the internal cooling channel, the sealing plates 6 are blown by the pressure generated by the cold air flow and tightly adhere to the outer surface of the blade, thereby preventing the intrusion of high-temperature combustion gases into the blade. The continuous flow of cold air always occupies the gap between the sealing plate 6 and the sealing surface, preventing combustion gases from penetrating through this gap, thus ensuring a sealed environment and operational safety inside the blade and improving the reliability of the blade.

[0050] Reference Figure 3 The sealing sheet 6 may have gas film holes 7 distributed on it. When cold air flows out from the gas film holes 7, a protective gas film will be formed, which will reduce the temperature of the sealing sheet 6 and the surface of the blade, reduce thermal stress, and further prevent high-temperature combustion gas from entering.

[0051] In a preferred embodiment of the present invention, the sealing plate structure 3 further includes a plurality of baffle columns 8 arranged along the spanwise direction of the blade on both the pressure surface side and the suction surface side of the blade. Two baffle columns 8 at corresponding positions on each side are fixed to the grooves of the blade body and trailing edge structure at both ends of the sealing plate 6, thereby constraining the movement of the sealing plate 6 in the flow direction within the grooves. This ensures that the sealing plate 6 does not excessively swing or deviate in the flow direction under the action of high-speed airflow, avoiding deformation caused by the deviation or swing of the sealing plate 6 under complex aerodynamic loads, thus maintaining the high-efficiency operation of the engine and ensuring the performance stability and reliability of the entire device. On the other hand, the baffle columns 8 also serve to provide strength support for the sealing plate 6, thereby improving the structural strength of the blade.

[0052] Compared with existing gas turbine guide blades, the gas turbine guide blades provided by this invention adopt a porous material trailing edge structure with built-in cooling channels, which combines gas film cooling and evaporative cooling, improves the cooling effect of the blade suction surface, reduces local high temperature areas, reduces coolant consumption and pressure loss, and enhances the structural strength of the blade.

[0053] The following examples further illustrate the porous material trailing edge structure with built-in cooling channels provided by this invention.

[0054] In this example, a simulation analysis is performed on the trailing edge structure of a porous material with built-in cooling channels. The model includes the main gas flow, the porous material layer, and the Y-shaped bifurcated cooling channels. Two-dimensional geometric models were established for both the absence of cooling channels and the presence of built-in cooling channels.

[0055] In this example, the inherent pore diameter of the porous material =0.25mm, material wall thickness 7.5mm. Total number of stages in the Y-shaped bifurcation structure. Total series The branch with the most consecutive bifurcated nodes in the cooling channel network is used as the reference direction, i.e., the 0° direction, with the overall extension direction of the channel from the cooling channel inlet to the tail edge. Each branch angle refers to the angle between the corresponding branch centerline and this direction. The main pipe diameter of the first-stage Y-shaped bifurcation structure of the cooling channel is... mm, along the continuous bifurcation path, the diameters of the branch pipes at each level that serve as the next level of the main pipe are successively as follows: mm mm mm mm mm mm mm. The diameter ratio between two adjacent channels is approximately 0.673, satisfying the 1 / 2 to 3 / 4 diameter constraint specified in this invention; the diameter of the final branch pipe... mm, corresponding to the inherent pore diameter of the porous material being 0.25 mm. Furthermore, the length of the inlet manifold is... mm, the branch pipe lengths of the first to seventh level Y-shaped bifurcation structures are respectively: mm mm mm mm mm mm, mm.

[0056] The first-level Y-shaped bifurcation structure consists of a diameter The main pipe (mm) branches into two primary branches. One primary branch extends towards the suction surface 4 at a 60° angle; the other extends towards the pressure surface 5 at a 50° angle. In the pressure surface branch, the 50° primary branch serves as the main pipe for the second-stage Y-shaped bifurcation structure. This second-stage Y-shaped bifurcation structure branches into two branches. One branch extends to the surface of pressure surface 5 at a 90° angle; the other continues along the trailing edge towards the tail end at a 15° angle. This 15° branch serves as the main pipe for the third-stage Y-shaped bifurcation structure, which branches into two branches at 15° and 30° angles respectively. The 15° branch of the third stage serves as the main pipe for the fourth-stage Y-shaped bifurcation structure, with both branches extending to the surface of pressure surface 5 at 30° and 10° angles respectively. Therefore, three end-outflow branches are formed on the pressure surface 5 side.

[0057] The third-level 30° branch serves as the main pipe of another fourth-level Y-shaped bifurcation structure. This fourth-level Y-shaped bifurcation structure branches into two more branches extending further inward towards the trailing edge, with angles of 10° and 15° respectively. The 10° branch serves as the main pipe of the fifth-level Y-shaped bifurcation structure, with all its fifth-level branches having an angle of 0° and extending to the trailing edge end region. The 15° branch serves as the main pipe of another fifth-level Y-shaped bifurcation structure, with its fifth-level branches having angles of 5° and 0° respectively. The 5° branch of the fifth level serves as the main pipe of the sixth-level Y-shaped bifurcation structure, with all its sixth-level branches having an angle of 0° and extending to the trailing edge end region. The 0° branch of the fifth level serves as the main pipe of another sixth-level Y-shaped bifurcation structure, with all its sixth-level branches having an angle of 35° and extending to the suction surface 4.

[0058] In the suction surface side branch, a 60° primary branch serves as the main pipe for the second-stage Y-shaped bifurcation structure. The second-stage Y-shaped bifurcation structure branches into two branches: one extends to the surface of suction surface 4 at a 90° angle; the other continues forward along the inner edge at a 0° angle. This 0° branch serves as the main pipe for the third-stage Y-shaped bifurcation structure, which branches into two branches: one extends to the surface of suction surface 4 at a 40° angle; the other continues forward at a 0° angle. This 0° branch serves as the main pipe for the fourth-stage Y-shaped bifurcation structure, which branches into two branches: one extends to the surface of suction surface 4 at a 45° angle; the other continues forward at a 5° angle. The 5° branch pipe serves as the main pipe of the fifth-stage Y-shaped bifurcation structure. This fifth-stage Y-shaped bifurcation structure branches into two branches, one extending to the suction surface 4 at a 30° angle, and the other continuing forward at a 5° angle. The 5° branch pipe also serves as the main pipe of the sixth-stage Y-shaped bifurcation structure. This sixth-stage Y-shaped bifurcation structure branches into two branches, one extending to the suction surface 4 at a 50° angle, and the other continuing forward at a 25° angle. The 25° branch pipe serves as the main pipe of the seventh-stage Y-shaped bifurcation structure. Both branches of this seventh-stage Y-shaped bifurcation structure extend to the suction surface 4 at angles of 60° and 50°, respectively. Therefore, a total of nine end-outflow branch pipes are formed on the suction surface 4 side.

[0059] Therefore, the number of end outlet branches extending to the pressure surface 5 is 3, and the number of end outlet branches extending to the suction surface 4 is 9. In this example... .

[0060] To verify the diameter ratio defined in this invention The superiority, limited to the range of 1 / 2 to 3 / 4, is based on the aforementioned six-stage Y-shaped bifurcation channel model, with only the diameter ratio of each stage being changed. Under the same inlet flow rate and the same heat flux density boundary conditions, numerical simulations were conducted to compare the channel pressure drop, maximum temperature difference on the trailing edge surface (suction surface and pressure surface), and film cooling efficiency under different diameter ratios. The results are shown in Table 1.

[0061] Table 1 Based on Different diameter ratios in mm Comparison of trailing edge cooling performance

[0062]

[0063] As can be seen from Table 1: when the diameter ratio When the value is too small (e.g., 0.30, 0.40), the branch pipe contracts sharply relative to the main pipe. According to the relationship between local resistance and cross-sectional area change (flow resistance is inversely proportional to the fourth power of the diameter), the flow resistance of the long branch pipe on the suction side increases exponentially. This causes most of the coolant to accumulate on the near end or pressure side, with almost no coolant covering the end of the suction side at the trailing edge. The temperature difference between the suction side and the pressure side is as high as 160K or more, and the air film efficiency of the suction side is only 0.42~0.48, which is completely unable to meet the uniform cooling requirements of the turbine guide vanes.

[0064] When the diameter ratio When the value is too large (e.g., 0.85, 0.95), the branch pipes do not contract sufficiently relative to the main pipe. The momentum effect at each bifurcation node causes the coolant to tend to rush straight to the near-end outlet along the path of least axial resistance (i.e., the "short-circuit effect"). It cannot effectively force the coolant to turn and enter the ends of the slender branch pipes on both sides. This also causes a vacuum in the liquid supply at the suction surface and tip of the tail edge. The gas film efficiency of the suction surface drops below 0.50, the local temperature rises sharply, and the risk of thermal stress increases significantly.

[0065] Only when When strictly limited to between 1 / 2 and 3 / 4, the contraction rate of the branch pipe can produce an appropriate "throttling and diversion" effect, ensuring sufficient pressure difference to drive the coolant flow to the suction surface and the tip of the trailing edge, without blocking the flow due to excessive resistance. At this time, the temperature difference between the suction surface and the pressure surface at the trailing edge is effectively controlled within 94K, and the film cooling efficiency of the suction surface remains stably above 0.64. Especially when When the efficiency is approximately 0.673, the cooling efficiency of the suction surface and the pressure surface is optimally matched (suction surface air film efficiency 0.73, pressure surface air film efficiency 0.78), which effectively solves the defects of insufficient cooling of the suction surface and large temperature difference between the two sides in the traditional tail edge structure.

[0066] The flow path of the coolant is as follows Figure 4 As shown, the coolant flows into the main pipe of the first-stage Y-shaped bifurcation structure from the cooling channel inlet at the front of the tail edge. It then branches into two branch pipes at the bifurcation node, passing through the second to sixth stages of bifurcation, and finally seeps out from the ends of each branch pipe onto the porous material surface. During this process, the coolant achieves evaporative cooling through permeation into the porous medium, and simultaneously forms a film cooling effect within the channels. Because the number of cooling channels on the suction side is greater than that on the pressure side, and the diameter ratio of each channel is strictly constrained to 1 / 2 to 3 / 4, the coolant supply on the suction side is sufficient to compensate for its higher heat load, achieving a balanced cooling effect on both sides.

[0067] Figure 5 and Figure 6The comparison of film cooling efficiency on the suction and pressure surfaces with and without built-in Y-shaped bifurcated cooling channels is shown. As can be seen from the figures, the porous material with built-in Y-shaped bifurcated cooling channels exhibits improved film cooling efficiency on both the suction and pressure surfaces under the influence of high-temperature combustion gases. The cooling film formed by the coolant on the trailing edge effectively blocks the high-temperature combustion gases, reducing heat transfer to the material's interior. This demonstrates that the Y-shaped bifurcated cooling channel can simultaneously improve the cooling efficiency of both the suction and pressure surfaces, improve the heat flux distribution on the blade surface, reduce localized high-temperature zones, and enhance the blade's thermal stability.

[0068] Simulation results show that the Y-shaped bifurcated cooling channel can improve the cooling effect of the trailing edge pressure surface and suction surface, avoiding the problem of insufficient cooling of the suction surface in previous cooling structures. Furthermore, simulation results also indicate that the Y-shaped bifurcated cooling channel design can optimize the coolant flow path; a reasonable design can reduce flow resistance and pressure loss, decrease coolant consumption, and thus improve engine operating economy.

[0069] Finally, it should be noted that the features mentioned and / or shown in the above description of exemplary embodiments of the present invention can be combined in the same or similar manner with one or more other embodiments, combined with features in other embodiments, or substituted for corresponding features in other embodiments. These combined or substituted technical solutions should also be considered to be included within the scope of protection of the present invention.

Claims

1. A porous material tail edge structure with built-in cooling channels, characterized in that: Sintered porous materials are used to form the trailing edge of gas turbine guide vanes, and cooling channels for coolant flow are provided within the sintered porous materials. The cooling channel has a multi-level Y-shaped bifurcation structure, extending from the front of the tail edge to the pressure surface, suction surface and tail, with the number of cooling channels extending to the suction surface being greater than the number extending to the pressure surface; each Y-shaped bifurcation structure in each level forms a three-way structure at the bifurcation node, and differentiates into two branches from a single main pipe along the coolant flow direction, with the branch pipe of each level of Y-shaped bifurcation structure serving as the main pipe of the next level of Y-shaped bifurcation structure; The cooling channel has a cylindrical structure; the first... The diameter of the main pipe of the Y-shaped bifurcation structure is The diameter of the branch pipe is , No. The diameter of the main pipe of the Y-shaped bifurcation structure is also... It satisfies the following relationship: .

2. The porous material tail edge structure with built-in cooling channels according to claim 1, characterized in that: Number of cooling channels extending to the suction surface The number of cooling channels extending to the pressure surface The relationship between them is: .

3. The porous material trailing edge structure with built-in cooling channels according to claim 1, characterized in that: The diameter of the branch pipe of the final Y-shaped branch structure of the cooling channel is equal to the inherent pore diameter of the porous material.

4. The porous material tail edge structure with built-in cooling channels according to any one of claims 1 to 3, characterized in that: The diameter of the main pipe of the first-stage Y-shaped bifurcation structure of the cooling channel The total number of levels of the Y-shaped bifurcation structure and the inherent pore diameter of porous materials Constraints: .

5. A gas turbine guide vane, characterized in that: The blade includes a blade body and a porous material trailing edge structure with a built-in cooling channel as described in any one of claims 1 to 4. The two ends of the blade body and the trailing edge structure are respectively used to fix to the end wall of the upper guide vane and the end wall of the lower guide vane. The trailing edge structure and the blade body are provided with sealing plates at their respective positions on the pressure side and suction side. The two ends of each sealing plate are respectively accommodated in the grooves at their respective positions on the blade body and the trailing edge structure. The sealing plates can be blown by the pressure generated by the flow of cold air to fit against the outer surface of the blade, thereby preventing the combustion gas from entering the interior of the guide vane.

6. The gas turbine guide vane according to claim 5, characterized in that: It also includes multiple turbulence columns arranged along the blade spanwise on both the pressure side and the suction side. Two turbulence columns at corresponding positions on each side are fixed to the grooves of the blade body and the trailing edge structure at both ends of the sealing sheet, so as to constrain the movement of the sealing sheet in the groove along the flow direction at both ends of the sealing sheet.

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