A cooling structure and method for a gas turbine turbine vane trailing edge region

Abstract

The application relates to a cooling structure and method for the trailing edge area of a gas turbine turbine vane, belonging to the technical field of gas turbine turbine cooling, which comprises a vane trailing edge pressure surface, a vane trailing edge suction surface and a vane trailing edge half-split joint structure, the two sides of the vane trailing edge are divided into the vane trailing edge pressure surface and the vane trailing edge suction surface, two rows of circular holes are arranged on the vane trailing edge pressure surface, one row of trapezoidal holes is arranged on the vane trailing edge suction surface, and a thermal barrier layer is arranged on the outer surface of the vane trailing edge suction surface. With the improvement of the performance of the gas turbine, the thickness of the vane trailing edge is thinned, the cold gas at the outlet of the half-split joint structure is mixed with high-temperature gas, the temperature at the vane trailing edge is relatively high, and the cooling effect is poor. The trapezoidal holes arranged on the vane trailing edge suction surface can realize pressure increase and speed reduction of the cold gas, increase the residence time of the cold gas, make the unit cold gas take away more heat, improve the utilization rate of the cold gas and reduce the aerodynamic loss.

Description

Technical Field

[0001] This invention relates to a cooling structure for the trailing edge region of a gas turbine turbine stator blade, belonging to the field of gas turbine cooling technology. Background Technology

[0002] To improve the efficiency of gas turbines, the gas temperature is gradually increasing. The inlet temperature of existing gas turbines already far exceeds the heat resistance limit of blade materials. Therefore, protecting the blades from thermal erosion is crucial.

[0003] Currently, the cooling methods for turbine blade leading edges are relatively mature, often employing a combination of impingement cooling and film cooling. Cooling gas flows through impingement cooling holes to form a high-speed jet, impacting the blade's leading edge target surface and cooling the blade. The cooled gas then flows out through film cooling holes arranged along the leading edge, forming a cool gas film on the blade surface, isolating the blade from the high-temperature combustion gas and effectively protecting it. However, cooling methods for blade trailing edges are relatively scarce. As gas turbine performance continues to improve, the thickness of blade trailing edges is constantly decreasing, making the fabrication of fully slotted cooling structures, which offer better cooling performance, difficult. Furthermore, in semi-slotted structures, the cooled gas at the outlet mixes with the high-temperature combustion gas, resulting in higher temperatures at the blade trailing edge and poorer cooling performance.

[0004] Therefore, there is an urgent need to propose a new cooling structure for the trailing edge region of the turbine stator blades in gas turbines to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to address the problems in existing technologies where, with the continuous improvement of gas turbine performance and the decreasing thickness of blade trailing edges, the fabrication of fully slotted cooling structures with good cooling effects becomes difficult. Furthermore, in semi-slotted structures, the mixing of cold air and high-temperature combustion gas at the outlet leads to higher temperatures at the blade trailing edges and poorer cooling performance. A brief overview of this invention is provided below to offer a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0006] The technical solution of this invention:

[0007] Option 1: A cooling structure for the trailing edge region of a gas turbine turbine stator blade, comprising a blade trailing edge pressure surface, a blade trailing edge suction surface, and a blade trailing edge semi-slit structure. The two sides of the blade trailing edge are divided into a blade trailing edge pressure surface and a blade trailing edge suction surface. Two rows of circular holes are arranged on the blade trailing edge pressure surface, with the arrangement direction of the circular holes being the height direction of the blade trailing edge. A row of trapezoidal holes is arranged on the blade trailing edge suction surface. The inner surface of the blade trailing edge suction surface is provided with semi-cylindrical longitudinal ribs and cuboid transverse ribs, and the outer surface of the blade trailing edge suction surface is provided with a thermal barrier layer.

[0008] Preferably, the blade trailing edge semi-slit structure includes a rectangular cold air inlet, a trailing edge semi-slit surface, and a trailing edge separating rib. A rectangular cold air inlet is provided on the trailing edge of the blade. While cutting off part of the blade trailing edge pressure surface, the blade trailing edge suction surface is retained. The cut-off area forms the trailing edge semi-slit surface, and a trailing edge separating rib is provided on the trailing edge semi-slit surface.

[0009] Preferably, the trapezoidal hole includes a first trapezoidal hole and a second trapezoidal hole. The two sides of the first trapezoidal hole gradually expand from the inner surface of the suction surface of the blade trailing edge to the outer surface. The second trapezoidal hole expands from the bottom surface of the second trapezoidal hole on the basis of the gradual expansion of the two sides of the first trapezoidal hole. The trapezoidal holes are arranged in the height direction of the blade trailing edge.

[0010] Preferably, the longitudinal ribs are oriented in the height direction of the blade trailing edge, and the transverse ribs are perpendicular to the longitudinal ribs.

[0011] Preferably, the thermal barrier coating comprises an adhesive layer and a ceramic layer.

[0012] Preferably, the adhesive layer has a thickness of 0.25 mm and the ceramic layer has a thickness of 0.38 mm.

[0013] Option 2: A method for cooling the trailing edge region of a gas turbine turbine stator blade, based on the cooling structure for the trailing edge region of a gas turbine turbine stator blade as described in claim 6, includes the following steps:

[0014] Step 1. When the gas turbine is running, the cool air used to cool the blades flows from the tip of the blade to the root along the height of the trailing edge of the blade. At the pressure surface of the trailing edge of the blade, a portion of the cool air flows out from the circular holes under the suction of the two rows of circular holes and covers the pressure surface of the blade, thus separating the blade from the high-temperature gas.

[0015] Step 2. At the same time, on the inner surface of the suction surface at the trailing edge of the blade, a portion of the cold air flows through the semi-cylindrical longitudinal rib and the cuboid transverse rib, which increases the heat exchange area of ​​the cold air.

[0016] Step 3. Then the cold air flows into the expanding trapezoidal hole. The cold air is pressurized and slowed down in the expanding trapezoidal hole, which increases the residence time of the cold air and allows the unit of cold air to remove more heat.

[0017] Step 4. When the cold air flows through the second trapezoidal hole, the expanded lower surface increases the degree of expansion of the trapezoidal hole, further pressurizing and decelerating the cold air, while guiding the outflowing cold air to better adhere to the suction surface of the blade trailing edge.

[0018] Step 5. The cold air flowing out of the expanding trapezoidal hole covers the suction surface of the blade trailing edge, separating the blade from the high-temperature combustion gas;

[0019] Step 6. The remaining cold air enters the blade trailing edge semi-slit structure through the rectangular cold air inlet, forming a cold air film on the surface 16 of the trailing edge semi-slit, thus separating the combustion gas from the blade trailing edge.

[0020] Step 7. A thermal barrier coating is provided on the outer surface of the suction surface at the trailing edge of the blade to share the heat load on the outer surface of the suction surface at the trailing edge of the blade.

[0021] The present invention has the following beneficial effects:

[0022] 1. The present invention, with the combined action of the internal semi-cylindrical longitudinal ribs and cuboid transverse ribs and the external thermal barrier coating, combined with a row of trapezoidal holes opened on the suction surface of the blade, can meet the protection of the blade. Moreover, the trapezoidal holes are in an expanded form. The effect of the expansion trapezoidal holes causing the pressurization and deceleration of the cold air, which leads to the weakening of heat exchange, will not affect the protection of the blade.

[0023] 2. This invention utilizes various forms of circular and trapezoidal holes, and various forms of turbulence ribs in the cooling channel, namely semi-cylindrical longitudinal ribs and cuboid transverse ribs. At the same time, it sets up a thermal barrier coating and a blade trailing edge semi-slit structure to reduce aerodynamic losses in multiple ways while ensuring the safety of the blade trailing edge area.

[0024] 3. The present invention has a row of expanding trapezoidal holes arranged on the suction surface of the blade trailing edge. The expanding trapezoidal holes can realize the pressure increase and speed reduction of the cold air, increase the residence time of the cold air, so that the unit of cold air can carry away more heat, improve the utilization rate of the cold air, and reduce aerodynamic losses.

[0025] 4. In this invention, when the cold air flows through the second trapezoidal hole, the expanded lower surface can guide the outflowing cold air to better adhere to the suction surface of the blade, thus improving the isolation effect from the combustion gas. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a cooling structure for the trailing edge region of a gas turbine stator blade.

[0027] Figure 2 yes Figure 1 A–A cross-section;

[0028] Figure 3 This is a schematic diagram of the trapezoidal hole structure of the present invention;

[0029] Figure 4 This is a schematic diagram of the thermal barrier layer of the present invention;

[0030] In the figure, 1-blade trailing edge pressure surface, 2-blade trailing edge suction surface, 3-blade trailing edge semi-slit structure, 4-circular hole, 5-trapezoidal hole, 6-first part of trapezoidal hole, 7-side surface, 8-second part of trapezoidal hole, 9-bottom surface, 10-semi-cylindrical longitudinal rib, 11-cubic transverse rib, 12-thermal barrier layer, 13-adhesive layer, 14-ceramic layer, 15-rectangular cold air inlet, 16-trailing edge semi-slit surface, 17-trailing edge separating rib. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0032] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as threaded connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can always be found to achieve the function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a hinged connection can be chosen for detachable connections.

[0033] Specific implementation method one: Combining Figures 1-4 This embodiment describes a cooling structure for the trailing edge region of a gas turbine turbine stator blade, comprising a blade trailing edge pressure surface 1, a blade trailing edge suction surface 2, and a blade trailing edge semi-slit structure 3. The two sides of the blade trailing edge are divided into the blade trailing edge pressure surface 1 and the blade trailing edge suction surface 2. Two rows of circular holes 4 are arranged on the blade trailing edge pressure surface 1, with the arrangement direction of the circular holes 4 being the height direction of the blade trailing edge. A row of trapezoidal holes 5 are arranged on the blade trailing edge suction surface 2. The inner surface of the blade trailing edge suction surface 2 is provided with semi-cylindrical longitudinal ribs 10 and cuboid transverse ribs 11. The direction of the longitudinal ribs 10 is the height direction of the blade trailing edge, and the direction of the transverse ribs 11 is perpendicular to the direction of the longitudinal ribs 10. The outer surface of the blade trailing edge suction surface 2 is provided with a thermal barrier layer 12.

[0034] The trapezoidal hole 5 includes a first trapezoidal hole 6 and a second trapezoidal hole 8. The two sides 7 of the first trapezoidal hole 6 gradually expand from the inner surface of the suction surface 1 at the trailing edge of the blade to the outer surface. The second trapezoidal hole 8 expands from the lower bottom surface 9 of the second trapezoidal hole 8 based on the gradual expansion of the two sides 7 of the first trapezoidal hole 6. The trapezoidal holes 5 are arranged in the height direction of the trailing edge of the blade.

[0035] The blade trailing edge semi-slit structure 3 includes a rectangular cold air inlet 15, a trailing edge semi-slit surface 16, and a trailing edge separating rib 17. A rectangular cold air inlet 15 is provided on the trailing edge of the blade. While cutting off part of the blade trailing edge pressure surface 1, the blade trailing edge suction surface 2 is retained. The cut-off part forms the trailing edge semi-slit surface 16, and the trailing edge separating rib 17 is provided on the trailing edge semi-slit surface 16.

[0036] The thermal barrier coating 12 includes an adhesive layer 13 and a ceramic layer 14. The adhesive layer 13 has a thickness of 0.25 mm, and the ceramic layer 14 has a thickness of 0.38 mm.

[0037] Specific Implementation Method Two: Combining Figures 1-4 This embodiment, based on the cooling structure for the trailing edge region of a gas turbine turbine stator blade described in Specific Embodiment 1, includes the following steps:

[0038] Step 1. When the gas turbine is in operation, the cool air used to cool the blades flows from the tip of the blade to the root along the height direction of the trailing edge of the blade. At the pressure surface 1 of the trailing edge of the blade, a part of the cool air flows out from the circular holes 4 under the suction of the two rows of circular holes 4 and covers the pressure surface 1 of the blade, thus separating the blade from the high temperature gas.

[0039] Step 2. At the same time, on the inner surface of the suction surface 2 at the trailing edge of the blade, a portion of the cold air flows through the semi-cylindrical longitudinal rib 10 and the cuboid transverse rib 11. The semi-cylindrical longitudinal rib 10 and the cuboid transverse rib 11 increase the heat exchange area of ​​the cold air and enhance the heat exchange of the cold air.

[0040] Step 3. Then the cold air flows into the expanding trapezoidal hole 5. The cold air is pressurized and decelerated in the expanding trapezoidal hole 5, which increases the residence time of the cold air, so that the unit cold air can carry away more heat, improve the utilization rate of the cold air, and reduce aerodynamic losses.

[0041] Step 4. When the cold air flows through the second trapezoidal hole 8, the expanding lower bottom surface 9 increases the expansion degree of the trapezoidal hole 8, further pressurizing and decelerating the cold air. At the same time, it guides the outflowing cold air to better adhere to the suction surface 2 at the trailing edge of the blade, resulting in a better separation effect from the combustion gas.

[0042] Step 5. The cold air flowing out from the expanded trapezoidal hole 5 covers the suction surface 2 of the blade trailing edge, thus separating the blade from the high-temperature combustion gas;

[0043] Step 6. The remaining cold air enters the blade trailing edge semi-slit structure 3 through the rectangular cold air inlet 15, forming a cold air film on the surface 16 of the trailing edge semi-slit, thus separating the combustion gas from the blade trailing edge.

[0044] Step 7. On the outer surface of the blade suction surface 2 corresponding to the semi-slit surface 16 of the trailing edge of the blade, since the cooling film of the semi-slit surface 16 of the trailing edge cannot be effectively cooled, and it is difficult to arrange film pores at this position, and the high-temperature gas pressure and flow velocity of the gas flowing through the blade suction surface are low and the heat load is strong, a thermal barrier coating 12 is provided on the outer surface of the blade suction surface 2 to share the heat load of the outer surface of the blade suction surface 2 and enhance the heat erosion resistance of the blade suction surface 2.

[0045] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cooling structure for the trailing edge region of a gas turbine turbine stator blade, characterized in that: It includes a blade trailing edge pressure surface (1), a blade trailing edge suction surface (2), and a blade trailing edge semi-slit structure (3). The two sides of the blade trailing edge are divided into a blade trailing edge pressure surface (1) and a blade trailing edge suction surface (2). Two rows of circular holes (4) are arranged on the blade trailing edge pressure surface (1). The arrangement direction of the circular holes (4) is the height direction of the blade trailing edge. A row of trapezoidal holes (5) is arranged on the blade trailing edge suction surface (2). The inner surface of the blade trailing edge suction surface (2) is provided with a semi-cylindrical longitudinal rib (10) and a cuboid transverse rib (11). The outer surface of the blade trailing edge suction surface (2) is provided with a thermal barrier coating (12). The blade trailing edge semi-slit structure (3) includes a rectangular cold air inlet (15), a trailing edge semi-slit surface (16), and a trailing edge separating rib (17). A rectangular cold air inlet (15) is provided on the trailing edge of the blade. While cutting off part of the blade trailing edge pressure surface (1), the blade trailing edge suction surface (2) is retained. The cut-off part forms the trailing edge semi-slit surface (16), and a trailing edge separating rib (17) is provided on the trailing edge semi-slit surface (16). The trapezoidal hole (5) includes a first trapezoidal hole (6) and a second trapezoidal hole (8). The two sides (7) of the first trapezoidal hole (6) gradually expand from the inner surface of the suction surface (1) of the blade trailing edge to the outer surface. The second trapezoidal hole (8) expands from the bottom surface (9) of the second trapezoidal hole (8) on the basis of the gradual expansion of the two sides (7) of the first trapezoidal hole (6). The trapezoidal holes (5) are arranged in the height direction of the blade trailing edge.

2. The cooling structure for the trailing edge region of a gas turbine turbine stator blade according to claim 1, characterized in that: The longitudinal rib (10) is oriented in the height direction of the blade trailing edge, and the transverse rib (11) is perpendicular to the longitudinal rib (10).

3. A cooling structure for the trailing edge region of a gas turbine turbine stator blade according to claim 2, characterized in that: The thermal barrier coating (12) includes an adhesive layer (13) and a ceramic layer (14).

4. A cooling structure for the trailing edge region of a gas turbine turbine stator blade according to claim 3, characterized in that: The adhesive layer (13) has a thickness of 0.25 mm, and the ceramic layer (14) has a thickness of 0.38 mm.

5. A method for cooling the trailing edge region of a gas turbine turbine stator blade, implemented based on the cooling structure for the trailing edge region of a gas turbine turbine stator blade as described in claim 4, characterized in that, Includes the following steps: Step 1. When the gas turbine is running, the cold air used to cool the blades flows from the tip of the blade to the root along the height direction of the trailing edge of the blade. At the pressure surface (1) of the trailing edge of the blade, a part of the cold air flows out from the circular holes (4) under the suction of the two rows of circular holes (4) and covers the pressure surface (1) of the blade, so that the blade is separated from the high temperature gas. Step 2. At the same time, on the inner surface of the suction surface (2) at the trailing edge of the blade, a portion of the cold air flows through the semi-cylindrical longitudinal rib (10) and the cuboid transverse rib (11), which increases the heat exchange area of ​​the cold air. Step 3. Then the cold air flows into the expansion trapezoidal hole (5). The cold air is pressurized and decelerated in the expansion trapezoidal hole (5), which increases the residence time of the cold air and allows the unit of cold air to carry away more heat. Step 4. When the cold air flows through the second trapezoidal hole (8), the expanded lower bottom surface (9) increases the expansion degree of the trapezoidal hole (8), and the cold air is further pressurized and decelerated. At the same time, the outflowing cold air is guided to better adhere to the suction surface (2) of the blade trailing edge. Step 5. The cold air flowing out from the expanded trapezoidal hole (5) covers the suction surface (2) of the blade trailing edge, thus separating the blade from the high-temperature combustion gas; Step 6. The remaining cold air enters the blade trailing edge semi-slit structure (3) through the rectangular cold air inlet (15), forming a cold air film on the surface (16) of the trailing edge semi-slit, thus separating the combustion gas from the blade trailing edge. Step 7. A thermal barrier coating (12) is provided on the outer surface of the suction surface (2) at the trailing edge of the blade to share the heat load on the outer surface of the suction surface (2) at the trailing edge of the blade.

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