Double wall cooled turbine blade with combination of triangular winglet and elliptical cylinder cooling structure

Abstract

Double-layer wall cooling turbine blade with combination cooling structure of triangular winglet and elliptical cylinder, the present application relates to a turbine blade, in order to solve the problem of poor cooling effect of turbine blade and affect the heat exchange efficiency, the present application comprises blade inner wall, blade outer wall and multiple cooling structures, the blade outer wall and the blade inner wall are arranged from outside to inside, the cooling channel is formed between the blade inner wall and the blade outer wall, and the tail edge slit is formed in the tail end of the blade outer wall and the blade inner wall respectively, multiple cooling structures are arranged in the cooling channel between the blade inner wall and the blade outer wall, multiple column ribs are arranged in the middle of the tail edge slit of the blade outer wall, and multiple impact holes are arranged in the leading edge of the inner wall.The present application belongs to the technical field of gas turbine.The uniformly distributed combination structure increases the heat exchange area, strengthens the longitudinal vortex between the double-layer wall, and greatly enhances the heat exchange between the double-layer wall at the cost of low flow loss.

Description

Technical Field

[0001] This invention relates to a turbine blade, specifically to a double-walled cooled turbine blade with a combined cooling structure of a triangular winglet and an elliptical cylinder. This invention belongs to the field of gas turbine technology. Background Technology

[0002] Gas turbines are characterized by their light weight, small size, high single-unit power, rapid start-up, low pollution, high thermal efficiency, and good economic performance. As can be seen from the simple cycle of a gas turbine, increasing the initial gas temperature improves specific power and performance. Turbine blades operate in high-temperature, complex-stress, and harsh environments; therefore, their safe and reliable operation is crucial to engine performance. Various performance indicators of the blades have become important indicators for measuring the development level of an engine, especially the turbine blades' ability to withstand high temperatures. In short, the development level of turbine blades has become an important indicator of a country's gas turbine development level.

[0003] Currently, the temperature inlet of gas turbine blades has long exceeded the temperature under load of the materials. Ensuring the safe and reliable operation of the blades is achieved primarily through two approaches: improving the high-temperature resistance of the materials and employing more efficient cooling methods to reduce the blade temperature. Based on available data, the turbine inlet temperature has increased by an average of 22K per year over the past few decades. Of this, 70% is attributable to the adoption of more effective cooling methods, and 30% is due to improvements in the heat resistance of component materials and advancements in manufacturing processes. With the development of cooling methods and the introduction of new heat transfer mechanisms, the turbine inlet temperature will gradually increase.

[0004] Research has revealed that the improvement in turbine inlet temperature brought about by heat-resistant materials is not significant. However, since the adoption of composite cooling methods that enhance convective heat transfer, such as film cooling and impingement cooling, the inlet temperature of gas turbines has seen a remarkably significant increase. Statistics show that in recent years, 70% of the increase in turbine inlet temperature is attributable to the continuous development of turbine blade cooling technology, while the development of heat-resistant materials and advanced processing techniques (such as thermal barrier coatings, single-crystal blades, and advanced alloy materials) account for only about 30%. Therefore, to improve the heat resistance characteristics of hot-end components of gas turbines, it is essential to accelerate the development of turbine blade cooling technology. Summary of the Invention

[0005] In order to improve the heat resistance of hot-end components of gas turbines and solve the problem of poor turbine blade cooling effect that affects heat exchange efficiency, this invention proposes a double-wall cooling turbine blade with a combination cooling structure of triangular winglets and elliptical cylinders.

[0006] The technical solution adopted by the present invention to solve the above problems is as follows:

[0007] The present invention includes an inner wall of a blade, an outer wall of a blade, and multiple cooling structures. The outer wall and the inner wall of the blade are arranged from the outside to the inside, and a cooling channel is formed between the inner wall and the outer wall of the blade. The trailing ends of the outer wall and the inner wall of the blade are respectively formed into trailing edge slits. Multiple cooling structures are arranged in the cooling channel between the inner wall and the outer wall of the blade. Multiple column ribs are arranged in the middle of the trailing edge slit of the outer wall of the blade, and multiple impact holes are arranged at the leading edge of the inner wall.

[0008] Furthermore, the plurality of impact holes located at the leading edge of the inner wall are arranged in a forked pattern.

[0009] Furthermore, the diameter of the impact hole is between 0.5 and 1 times the wall thickness.

[0010] Furthermore, the plurality of column ribs located in the middle of the trailing edge slit on the outer wall of the blade are arranged in a forked pattern, and the forked pattern is not less than three rows.

[0011] Furthermore, the plurality of cooling structures are evenly distributed from top to bottom and from left to right between the inner wall and the outer wall of the blade.

[0012] Furthermore, each cooling structure includes an elliptical cylinder and two triangular winglets. The elliptical cylinder is located between the inner wall and the outer wall of the blade, and the two triangular winglets are symmetrically arranged in a figure-eight shape on both sides of the elliptical cylinder, with one end of the triangular winglets connected to the outer wall.

[0013] Furthermore, the included angle α formed by the extensions of the two triangular winglets is 90°.

[0014] Furthermore, the distance between the inner wall and the outer wall of the blade is between 1 and 2 times the wall thickness.

[0015] The beneficial effects of this invention are:

[0016] 1. The present invention incorporates a turbine blade hybrid cooling structure that combines a triangular structure with an elliptical cylinder between the inner and outer walls of the blade. The double-wall cooling structure with the combination of triangular winglets and elliptical cylinder is evenly distributed in the cooling channel, so as to minimize the flow resistance, reduce the loss caused by the leakage of working fluid from the blade trailing edge, and improve the overall heat transfer efficiency.

[0017] 2. The present invention strengthens the trailing edge of the blade by adding a columnar rib structure to support the outer wall, thereby enhancing the strength of the trailing edge where the wall thickness is thinner. At the same time, the airflow from between the inner and outer walls and from the trailing edge of the inner wall impacts the cylindrical rib, further cooling the high-temperature trailing edge.

[0018] 3. Optimized blade structure can improve airflow dynamics and reduce energy loss, thereby improving turbine efficiency. This blade structure can reduce unevenness in the heat transfer process, making the heat transfer of the working fluid on the blade surface more uniform and improving the overall heat transfer efficiency.

[0019] 4. The present invention provides impact holes at the leading edge of the inner wall of the blade, which can cool the leading edge of the outer wall. The staggered arrangement allows the airflow after impact to flow more evenly to the triangular and columnar rib combination structure. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is the present invention. Figure 1 BB cross-section;

[0022] Figure 3 This is the present invention. Figure 1 CC cross-section;

[0023] Figure 4 This is a three-dimensional structural schematic diagram of the cooling structure combining the triangular winglet and the elliptical cylinder of the present invention.

[0024] Wherein: 1-inner wall of blade; 2-outer wall of blade; 3-impact hole; 4-pillar rib; 5-elliptical cylinder; 6-delta winglet. Detailed Implementation

[0025] Specific implementation method one: Combining Figure 1 This embodiment describes a double-walled cooled turbine blade with a combined cooling structure of a triangular winglet and an elliptical cylinder. It includes an inner wall 1 and an outer wall 2, arranged from the outside to the inside. A cooling channel is formed between the inner wall 1 and the outer wall 2, and trailing edge slits are formed at the tail ends of the outer wall 2 and the inner wall 1, respectively. The double-walled cooled turbine blade also includes multiple cooling structures arranged within the cooling channel between the inner wall 1 and the outer wall 2. Multiple column ribs 4 are provided in the middle of the trailing edge slit of the outer wall 2, and multiple impact holes 3 are provided at the leading edge of the inner wall.

[0026] Specific Implementation Method Two: Combining Figure 2 In this embodiment, the plurality of impact holes 3 located at the leading edge of the inner wall are arranged in a staggered pattern. This staggered arrangement of the impact holes 3 allows for a larger heat exchange surface area, thereby improving heat transfer efficiency. The impact holes 3 can cool the leading edge of the outer wall 2 of the blade, and the staggered arrangement ensures that the airflow after impact flows more evenly to the cooling structure and the column ribs 4.

[0027] The other components and connections in this embodiment are the same as in Specific Embodiment 1.

[0028] Specific implementation method three: Combining Figure 2 This embodiment describes an impact hole 3 whose diameter is between 0.5 and 1 times the wall thickness.

[0029] The other components and connections in this embodiment are the same as in specific embodiment one or two.

[0030] Specific implementation method four: Combination Figures 2 to 3 In this embodiment, the plurality of column ribs 4 located in the middle of the trailing edge slit of the outer wall 2 of the blade are arranged in a forked pattern, and the forked pattern is not less than three rows.

[0031] A columnar rib structure is added to the trailing edge slit of the outer wall 2 of the blade to support the outer wall and enhance the strength of the trailing edge where the wall thickness is thinner. At the same time, the airflow from between the inner and outer walls and from the trailing edge of the inner wall impacts the cylindrical rib, further cooling the high-temperature trailing edge.

[0032] The other components and connections in this embodiment are the same as those in specific embodiments one, two, or three.

[0033] Specific Implementation Method Five: Combining Figures 2 to 3 This embodiment describes a plurality of cooling structures that are evenly distributed from top to bottom and from left to right between the inner wall 1 and the outer wall 2 of the blade.

[0034] The cooling structure, which combines triangular winglets 6 and elliptical cylinders 5, is evenly distributed in the cooling channels, which minimizes flow resistance, reduces losses caused by leakage of working fluid from the blade trailing edge, and improves overall heat transfer efficiency.

[0035] The other components and connections in this embodiment are the same as those in specific embodiments one, two, three, or four.

[0036] Specific Implementation Method Six: Combination Figures 2 to 4 This embodiment describes a cooling structure comprising an elliptical cylinder 5 and two triangular winglets 6. The elliptical cylinder is located between the inner wall 1 and the outer wall 2 of the blade. The two triangular winglets 6 are symmetrically arranged in a figure-eight shape on both sides of the elliptical cylinder 5, and one end of the triangular winglets 6 is connected to the outer wall.

[0037] The maximum height of the delta winglet is 0.75 times the distance between the inner and outer walls of the blade; the chord length of the delta winglet is 5 times the distance between the inner and outer walls; and the thickness is 0.25 times the distance between the inner and outer walls. The major axis of the elliptical cylinder is 3 times the distance between the inner and outer walls, and the minor axis is equal to the distance between the inner and outer walls. All dimensions can be adjusted according to actual conditions.

[0038] A hybrid cooling structure combining a triangular structure and an elliptical cylinder is added between the inner and outer walls of the turbine blades. This structure generates a longitudinal vortex through the triangular structure. Compared with the transverse vortex generated by the commonly used straight ribs, the longitudinal vortex has the advantages of longer duration, higher heat transfer intensity, and lower drag loss. It can also increase the effective heat transfer area of ​​the turbine blade surface, increase the contact area between the blade surface and the fluid, and accelerate the rate of heat transfer, thereby improving heat transfer efficiency and enhancing heat exchange.

[0039] The inner and outer walls 1 of the blade are connected by an elliptical cylinder 5, which supports the blade, enhances its strength, makes the stress distribution more uniform, transfers heat between the inner and outer walls, increases the heat exchange area, improves the heat exchange effect, and, more importantly, can further strengthen the longitudinal vortex generated by the delta winglet 6, thereby enhancing the longitudinal vortex intensity and further enhancing the heat exchange.

[0040] The other components and connections in this embodiment are the same as those in specific embodiments one, two, three, four, or five.

[0041] Specific implementation method seven: Combination Figure 4 In this embodiment, the included angle α formed by the extensions of the two triangular winglets 6 is 90°.

[0042] An elliptical cylinder 5 connects the inner and outer walls of the blade. Triangular winglets 6 are symmetrically distributed on both sides of the cylinder and connected to the outer wall. The winglets form a 45° angle with the main flow, and their vertical feet are located upstream of the airflow. The ellipse is tangent to the leading edge of the winglets, and the lateral distance between the two winglets is equal to the minor axis of the ellipse. The triangular structure generates longitudinal vortices, minimizing flow resistance and improving overall heat transfer efficiency. The generation of these longitudinal vortices increases the heat transfer area of ​​the turbine blades, enhances heat transfer intensity, and increases the heat transfer rate.

[0043] The other components and connections in this embodiment are the same as those in specific embodiments one, two, three, four, five, or six.

[0044] Specific implementation method eight: Combination Figure 1 This embodiment describes a blade where the distance between the inner wall 1 and the outer wall 2 is between 1 and 3 times the wall thickness.

[0045] The other components and connections in this embodiment are the same as those in specific embodiments one, two, three, four, five, six, or seven.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A double-walled cooled turbine blade with a combined cooling structure of a triangular winglet and an elliptical cylinder, comprising an inner wall (1) and an outer wall (2), wherein the outer wall (2) and the inner wall (1) are arranged from the outside to the inside, a cooling channel is formed between the inner wall (1) and the outer wall (2), and trailing edge slits are formed at the trailing ends of the outer wall (2) and the inner wall (1), characterized in that: The double-walled cooled turbine blade with a combination of triangular winglets and elliptical cylinder cooling structure also includes multiple cooling structures. These multiple cooling structures are set in the cooling channel between the inner wall (1) and the outer wall (2) of the blade. Multiple column ribs (4) are provided in the middle of the trailing edge slit of the outer wall (2) of the blade, and multiple impact holes (3) are provided at the leading edge of the inner wall. Multiple cooling structures are evenly distributed from top to bottom and from left to right between the inner wall (1) and the outer wall (2) of the blade; Each of the cooling structures includes an elliptical cylinder (5) and two triangular winglets (6). The elliptical cylinder (5) is located between the inner wall (1) and the outer wall (2) of the blade. The two triangular winglets (6) are symmetrically arranged in a figure-eight shape on both sides of the elliptical cylinder (5), and one end of the triangular winglets (6) is connected to the outer wall. The included angle (a) formed by the extensions of the two triangular winglets (6) is 90°.

2. The double-walled cooled turbine blade with a combined cooling structure of triangular winglets and elliptical cylinders according to claim 1, characterized in that: The plurality of impact holes (3) located at the leading edge of the inner wall are arranged in a forked pattern.

3. The double-walled cooled turbine blade with a combined cooling structure of triangular winglets and elliptical cylinders according to claim 2, characterized in that: The diameter of the impact hole (3) is between 0.5 and 1 times the wall thickness.

4. The double-walled cooled turbine blade with a combined cooling structure of triangular winglets and elliptical cylinders according to claim 1, characterized in that: The multiple columnar ribs (4) located in the middle of the trailing edge slit on the outer wall (2) of the blade are arranged in a forked pattern, and the forked pattern is not less than three rows.

5. The double-walled cooled turbine blade with a combined cooling structure of triangular winglets and elliptical cylinders according to claim 1, characterized in that: The distance between the inner wall (1) and the outer wall (2) of the blade is between 1 and 3 times the wall thickness.

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