A high-efficiency cooling structure for turbine blade crowns with rotary cooling channels

Abstract

The purpose of this invention is to provide a high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel, belonging to the field of gas turbines. It includes blades, rim plates, tenons, and a crown. The crown is located above the blades, which are fixed to the tenons by the rim plates. A rotary cooling channel is installed inside the crown. The upper and lower surfaces of the crown have film cooling holes, and the pressure side of the blade has film cooling holes on its surface. Part of the cold air entering the blade flows out through the film cooling holes on the blade surfaces, while the other part enters the rotary cooling channel through the film cooling holes on the lower surface of the crown and flows out through the film cooling holes on the upper surface of the crown. This invention, by introducing a rotary cooling channel structure into the turbine blade crown, enhances internal convective heat transfer and simultaneously achieves leakage control. The circular film cooling holes form a surface isolation film, and this dual cooling mechanism significantly improves cooling performance, overcoming the limitations of traditional crowned blades that rely on simple geometric barriers.

Description

Technical Field

[0001] The present invention relates to an engine, specifically a turbine structure. Background Technology

[0002] As the requirements for output power and thrust-to-weight ratio in aero engines continue to increase, turbine inlet temperatures rise significantly. When high-temperature combustion gases flow at high speed through the turbine blade cascade, the blade crown, as the sealing structure at the tip of the blade, creates stagnation on its surface. As the airflow is obstructed and slowed, a large amount of kinetic energy is converted into heat energy. Simultaneously, the additional thermal shock from gas leakage causes the gas temperature near the blade crown surface to rise significantly higher than the mainstream gas temperature. This continuous and concentrated heat transfer to the blade crown easily leads to material degradation, deformation, or even ablation due to high temperatures. This not only damages the blade's sealing effect and exacerbates gas leakage but may also cause blade vibration, fatigue fracture, and other malfunctions, ultimately shortening the engine's service life.

[0003] When high-temperature mainstream combustion gas enters turbine blades, reducing tip leakage losses can effectively improve unit efficiency. Crowned blade tips, due to their ability to reduce leakage flow through the circumferential crown and radial serrations at the blade tip, are already used in low-pressure turbines. However, existing crowned blade tips still face the following technical bottlenecks in engineering applications: 1. The crown serration end region is prone to strong coupling and mixing of unsteady leakage jets and cavity vortices, significantly exacerbating local thermo-mechanical coupling and making the crown region a high-heat-load risk concentration area; 2. The crown cooling gas relies entirely on the blade's internal supply, limiting its circumferential coverage and making cooling layout difficult, hindering the achievement of uniform and effective thermal protection; 3. The crown has a large mass, and during high-speed rotation, the blade experiences excessive centrifugal force, easily leading to structural failure. Turbine rotor blades themselves operate in harsh environments of high temperature, high pressure, and high speed for most of their lifespan. Summary of the Invention

[0004] The purpose of this invention is to provide a high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel that can improve cooling coverage, reduce blade crown heat load, and reduce weight.

[0005] The objective of this invention is achieved as follows: This invention discloses a high-efficiency cooling structure for a turbine blade crown with a rotary cooling channel, characterized by comprising a blade, a rim plate, a tenon, and a blade crown. The blade crown is located above the blade, and the blade is fixed to the tenon by the rim plate. A rotary cooling channel is installed inside the blade crown. The upper surface of the blade crown is provided with upper surface film-forming holes, and the lower surface of the blade crown is provided with lower surface film-forming holes. The pressure side of the blade is provided with blade surface film-forming holes. Part of the cold air entering the blade flows out through the blade surface film-forming holes, and the other part enters the rotary cooling channel through the lower surface film-forming holes of the blade crown and flows out from the upper surface film-forming holes of the blade crown.

[0006] The present invention may also include: 1. The rotary cooling channel is formed by bending a hollow cuboid and spreading it outwards at the center of the blade crown. The bending number is 10-16 times. The air film pores on the upper surface of the blade crown are arranged along the rotary cooling channel. The center of the air film pores on the upper surface of the blade crown is located on the center line of the rotary cooling channel. The air film pores on the upper surface of the blade crown are equidistant from each other. The total area of ​​the air film pores on the upper surface of the blade crown does not exceed 70% of the upper surface area of ​​the rotary cooling channel in which they are located.

[0007] 2. The bends in the rotary cooling channel are at right angles.

[0008] 3. The width of the rotary cooling channel is 0.02 to 0.03 times the blade crown length, the height of the channel is 0.04 to 0.06 times the blade crown length, and the width-to-height ratio is 1 to 2.

[0009] 4. The left end of the rotary cooling channel is 5-15 mm from the leading edge of the blade crown, and the right end is 5-15 mm from the trailing edge of the blade crown.

[0010] 5. The inner wall of the rotary cooling channel is coated with a metal anti-corrosion layer.

[0011] 6. The width of the leaf crown is 0.6 to 0.7 times the length of the leaf crown, and the height is 0.04 to 0.05 times the length of the leaf crown.

[0012] 7. The radius of the air film pores on the upper surface of the leaf crown shall not exceed 0.02 times the leaf crown length, and the spacing between the pores shall not exceed 0.08 times the leaf crown length.

[0013] 8. The volume of the rotary cooling channel shall not be less than 60% of the total volume of the blade crown.

[0014] The advantages of this invention are as follows: By introducing a rotary cooling channel structure into the turbine blade crown, this invention enhances internal convective heat transfer and simultaneously achieves leakage control. The circular air film holes form a surface isolation air film, and the dual cooling mechanism significantly improves cooling performance. This invention breaks through the limitations of traditional crowned blades that rely on simple geometric barriers and has broad prospects for engineering applications.

[0015] The uniform layout of channels and air film pores optimizes temperature distribution, and the compact design achieves lightweight blade crown, reducing the risk of blade breakage due to centrifugal load.

[0016] The design parameters of this invention are highly adjustable and can be flexibly optimized according to different working conditions, thus possessing wide applicability.

[0017] To address the issue of high heat load on the low-pressure turbine blade crown and grating teeth, a film cooling hole is designed within the blade crown using a rotating cooling channel to improve circumferential cooling coverage and reduce the blade crown's heat load.

[0018] To address the issue of the large mass of the blade crown with a grate, a cooling channel was designed to reduce the mass of the original solid blade crown, thereby reducing the problem of blade breakage and structural failure caused by excessive centrifugal force during high-speed rotation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is a schematic diagram of the internal structure of the leaf crown; Figure 4 Comparison of overall temperature field distribution cloud maps for three turbine blade crown cooling structures; Figure 5 Comparison of surface temperature field cloud maps for three turbine blade cooling structures.

[0020] Figure reference numerals: 1. Blade crown grate, 2. Air film pores on the upper surface of the blade crown, 3. Air film pores on the lower surface of the blade crown, 4. Blade, 5. Blade pressure side, 6. Tenon, 7. Edge plate, 8. Blade suction side, 9. Air film pores on the blade surface, 10. Rotary cooling channel, 11. Blade crown, 12. Internal cooling channel of the blade. Detailed Implementation

[0021] The invention will now be described in more detail with reference to the accompanying drawings: Combination Figure 1-5 The present invention discloses a high-efficiency cooling structure for turbine blades with a rotary cooling channel, comprising blades 4, a flange 7, a tenon 6, and a blade crown 11. The blades 4 are fixed to the tenon 6 by the flange 7. The blades 4 are composed of a suction surface 8 and a pressure surface 5. The blade crown 11 is located above the blades 4 and is smoothly connected to the suction surface 8 and the pressure surface 5 of the blades. A rotary cooling channel 10 is installed inside the blade crown 11. The upper surface of the blade crown 11 is provided with upper surface air film holes 2, the lower surface of the blade crown 11 is provided with lower surface air film holes 3, and the pressure side 5 of the blade is provided with blade surface air film holes 9. Part of the cold air entering the interior of the blades 4 flows out through the blade surface air film holes 9, and the other part enters the rotary cooling channel 10 through the lower surface air film holes 3 and flows out from the upper surface air film holes 2.

[0022] Considering the uniformity of cooling airflow within the leaf canopy, the rotary cooling channel 10 is located at the center of the leaf canopy and laid out horizontally.

[0023] Leaf crown 11: length range: 125-135mm, width range: 91.7-92.7mm, leaf crown length 0.6-0.7mm, height range: 5-5.5mm, leaf crown length 0.04-0.05mm.

[0024] The rotary cooling channel 10 has a rectangular cross-sectional shape, with an inner width ranging from 4 to 6 mm and an inner height ranging from 3 to 4 mm, resulting in a width-to-height ratio of 1 to 2. It has no rounded corners. The flow area of ​​the rotary cooling channel 10 is A. C =W×H, Rotary channel flow area range: 9~16mm² 2 .

[0025] The rotary cooling channel 10 has an inner width of 0.02–0.03 times the blade crown length and an inner height of 0.04–0.06 times the blade crown length, with a width-to-height ratio of 1–2.

[0026] The total flow length of the rotary cooling channel 10 ranges from 450 to 550 mm.

[0027] The rotary cooling channel 10 bends along θ=90°, with the number of bends ranging from 10 to 16.

[0028] Based on the inner curvature radius of the channel centerline of 3-5mm (0.02-0.03 leaf crown length) and the straight section length of 20-25mm (0.15-0.20 leaf crown length), they are arranged at equal intervals.

[0029] The left end of the rotary cooling channel 10 is 5-15 mm from the leading edge of the leaf crown and the top edge, and the right end is 5-15 mm from the trailing edge of the leaf crown and the top edge.

[0030] The inlet and outlet cross-sectional dimensions of the rotary cooling channel 10 are consistent with the main body dimensions of the channel. To improve cooling efficiency, the center of the circular air film holes on the rotary cooling channel 10 is located on the centerline of the channel. The radius of the air film holes ranges from 1.5 to 2.5 mm (0.01 to 0.02 mm of the blade crown length), and the hole spacing ranges from 6 to 10 mm (0.05 to 0.07 mm of the blade crown length). They are arranged at equal intervals on the channel, and the hole area does not exceed 70% of the channel area.

[0031] The cooling gas in the rotary cooling channel 10 is supplied by the cooling gas in the internal cooling channel 12 of the blade 4. It flows into the cooling chamber along the air film holes 3 on the lower surface of the blade crown. Under the centrifugal force brought by the rotation, it diffuses evenly in the cooling chamber and flows out from the air film holes 2 on the upper surface of the blade crown.

[0032] The inner wall of the rotary cooling channel 10 can be coated with a metal anti-corrosion layer to prevent internal corrosion of the blades in a high-salt working environment.

[0033] The rotary cooling channel 10 is spread out as evenly as possible within the blade crown 11 to ensure uniform heat exchange between the cooling gas and the blade crown 11.

[0034] Cooling gas is discharged through film cooling holes and mixed with leakage vortices formed in the blade tip gap, reducing the temperature of the blade crown surface and grate, thus achieving the desired effect.

[0035] The specific usage of this invention is as follows: When the high-temperature mainstream combustion gas enters blade 4, it acts on the blade pressure surface, causing the blade to rotate. Under the action of centrifugal force, cooling air enters the internal cooling channel 12 of the blade. Part of the cooling gas flows out along the film cooling holes on the blade surface to cool the blade, and the cooled air after heat exchange mixes with the mainstream combustion gas. Another part of the cooling gas flows into the cooling chamber along the film cooling holes 3 on the lower surface of the blade crown. As mentioned earlier, considering the uniformity of cooling, the circular film cooling holes should be evenly spaced, with the center located on the centerline of the cooling channel. The radius of the film cooling holes should not exceed 2.5 mm (0.02 blade crown length), and the spacing between the holes should not exceed 10 mm (0.08 blade crown length). After sufficient heat exchange in the cooling chamber, the cooled air flows out through the film cooling holes 2 on the upper surface of the blade crown, mixes with the leakage flow between the blade tips, and enters the mainstream combustion gas, achieving the purpose of efficient cooling of the crowned blades of the gas turbine.

[0036] To ensure improved cooling efficiency, the following estimates are made: Blade volume V1 = S × h = 66,000 mm², cooling channel volume V2 = a × S × h = 42,000 mm², and the cooling chamber volume accounts for more than 60% of the total blade volume.

[0037] In addition, by appropriately adjusting the size and layout of the cooling channels and air film holes, it can be applied to multiple scenarios, which are briefly listed below.

[0038] Applied to high-power laser diode heat dissipation modules, by designing the cooling channel as a miniaturized rotating structure (section 1~1.5mm×0.5~1mm), inert cooling gas is ejected from the gas film holes, which can quickly remove the high-density heat during diode operation, suppress thermal drift, and stabilize laser output power.

[0039] It is used for thermal protection of the extended section of rocket nozzles. By using high-temperature resistant niobium alloy to make the channel and nozzle base, the total length of the cooling channel is extended. The gas film holes are arranged axially along the inner wall of the nozzle, which can form a continuous low-temperature gas film to isolate the high-temperature gas, reduce the nozzle wall temperature, avoid ablation and deformation, and improve the reliability of the spacecraft propulsion system.

[0040] It is applied to the thermal management of high-power fast-charging battery packs. By designing the cooling channel into a flat, rotating layout and spraying heat-conducting coolant mist through the air film holes, the large amount of heat generated by the battery during fast charging can be quickly and evenly dissipated, preventing thermal runaway and extending the battery cycle life.

[0041] This invention incorporates several sets of rotating cooling channels 10 embedded inside the blade crown 11. These channels are square pipes with several air outlets on their upper and lower walls. This arrangement allows cooling gas to fully enter the blade crown for heat exchange during impeller rotation, thereby reducing the heat load on the blade tip and the metal surface of the blade crown.

[0042] Numerical simulation was performed using a rotor turbine blade of an aero-engine. The computational mesh was generated using the commercial software Workbench. All meshes were generated using polyhedral unstructured meshes, and local refinement was performed in the near-wall region to ensure that the number of boundary layers was at least 10 layers. At the same time, the dimensionless wall distance (y+) of the first layer of boundary layer mesh cells was ensured to meet the computational requirements, that is, the dimensionless distance y+ value was required to be less than 1. The number of meshes was 4.03 million.

[0043] Numerical calculations were performed using the ANSYS CFX platform, by solving the three-dimensional steady-state Reynolds-averaged Navier-Stokes equations. The convergence criteria for the continuity and momentum equations were set to a residual of 1×10⁻⁴, while the convergence criterion for the energy equation was set to 1×10⁻⁶. An implementable SST k-ε turbulence model was employed in this patent. All numerical calculation models used standardized boundary parameter configurations: inlet total pressure 126.9 kPa, inlet total temperature 297 K, cooling gas total temperature 247 K, cooling medium inlet temperature set to a constant 247 K, and outlet boundary defined as a static pressure condition of 102.7 kPa. Adiabatic conditions were applied to all non-boundary surfaces, and no-slip velocity boundaries were used across the entire wall region.

[0044] in, Figure 4 The image shows a comparison of temperature field distribution cloud maps for three turbine blade cooling structures. The upper left of the image shows the high-efficiency turbine blade cooling structure with a rotary cooling channel of the present invention, the upper right shows the turbine blade cooling structure with straight-through cooling holes and jet cooling, and the lower part shows the conventional turbine blade cooling structure. The cloud maps reflect the three-dimensional temperature distribution, cooling uniformity, and temperature peak characteristics of the three structures under the same thermal boundary. The results show that the rotary cooling channel of the present invention can significantly reduce the surface temperature of the blade and achieve high-efficiency cooling of the blade.

[0045] Figure 5 The comparison of surface temperature field cloud maps for three turbine blade cooling structures is a study of... Figure 4 Local refinement of the overall temperature field.

Claims

1. A high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel, characterized in that: It includes blades, rim plates, tenons, and a blade crown. The blade crown is located above the blades, and the blades are fixed to the tenons by the rim plates. A rotary cooling channel is installed inside the blade crown. The upper surface of the blade crown has upper surface air film pores, and the lower surface of the blade crown has lower surface air film pores. The pressure side of the blade has blade surface air film pores. Part of the cold air entering the blade flows out through the blade surface air film pores, and the other part enters the rotary cooling channel through the lower surface air film pores of the blade crown and flows out from the upper surface air film pores of the blade crown.

2. The turbine blade crown high-efficiency cooling structure with a rotary cooling channel according to claim 1, characterized in that: The rotary cooling channel is formed by bending a hollow cuboid and spreading it outwards at the center of the blade crown. The bending number is 10-16 times. The air film pores on the upper surface of the blade crown are arranged along the rotary cooling channel. The center of the air film pores on the upper surface of the blade crown is located on the center line of the rotary cooling channel. The air film pores on the upper surface of the blade crown are equidistant from each other. The total area of ​​the air film pores on the upper surface of the blade crown does not exceed 70% of the upper surface area of ​​the rotary cooling channel in which they are located.

3. The high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel according to claim 2, characterized in that: The bends in the rotary cooling channel are at right angles.

4. The high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel according to claim 1, characterized in that: The rotary cooling channel has an inner width of 0.02–0.03 times the blade crown length and an inner height of 0.04–0.06 times the blade crown length, with a width-to-height ratio of 1–2.

5. The high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel according to claim 1, characterized in that: The left end of the rotary cooling channel is 5-15 mm from the leading edge of the blade crown, and the right end is 5-15 mm from the trailing edge of the blade crown.

6. The high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel according to claim 1, characterized in that: The inner wall of the rotary cooling channel is coated with a metal anti-corrosion layer.

7. The high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel according to claim 1, characterized in that: The leaf crown width ranges from 0.6 to 0.7 times the leaf crown length, and the height ranges from 0.04 to 0.05 times the leaf crown length.

8. The high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel according to claim 1, characterized in that: The radius of the air film pores on the upper surface of the leaf crown should not exceed 0.02 times the leaf crown length, and the spacing between the pores should not exceed 0.08 times the leaf crown length.

9. A high-efficiency cooling structure for turbine blade crowns with a rotary cooling channel according to claim 1, characterized in that: The volume of the rotary cooling channel shall not be less than 60% of the total volume of the blade crown.

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