A turbine blade film cooling hole structure based on the rubbertear configuration

Abstract

A turbine blade film cooling hole structure based on the configuration of Roubert's tears comprises a straight pipe section, a diffusion section and a water drop section, the straight pipe section, the diffusion section and the water drop section are sequentially arranged, the small diameter end of the diffusion section is connected with the straight pipe section, the large diameter end of the diffusion section is connected with the water drop section, and the connection part of the diffusion section and the water drop section is a smooth transition; the gas inlet of the straight pipe section is used as the gas inlet of the film cooling hole, the gas outlet of the water drop section is used as the gas outlet of the film cooling hole, and the inside cavity of the gas outlet of the water drop section forms a cooling gas buffer cavity; the straight pipe section is arranged obliquely, and the central axis of the straight pipe section and the tangent plane of the cooled plane or the tangent surface of the cooled curved surface of the turbine blade form an included angle of 30-40 degrees. The turbine blade film cooling hole structure can effectively weaken the kidney-shaped vortex intensity of the outlet of the film cooling hole, thereby improving the film cooling efficiency, and can improve the coverage rate of the cooling film in the blade span direction, and through the increased cooling gas storage cavity, the performance of the film cooling can be effectively improved when the main flow changes sharply.

Description

Technical Field

[0001] This invention belongs to the field of turbine blade film cooling technology, and in particular relates to a turbine blade film cooling hole structure based on the Rupert's Tear configuration. Background Technology

[0002] Currently, the film cooling holes on gas turbine blades still mainly adopt the classic cylindrical configuration. However, the outlet of the cylindrical film cooling holes has flow structures such as the windward vortex, the leeward vortex, the opposite vortex pair (kidney vortex), and the horseshoe vortex. Among them, the kidney vortex and the horseshoe vortex will enhance the mixing of the mainstream high-temperature gas and the cold air flow, thus affecting the cooling efficiency.

[0003] Furthermore, since the spanwise dimension of the cylindrical film cooling holes is relatively small, it is difficult to increase the spanwise coverage of the film cooling system by increasing the number of film cooling holes. Even if the number of film cooling holes can be increased, the blade strength will decrease due to the increase in the number of film cooling holes, and the engine turbine efficiency will be reduced by increasing the amount of cooling air used.

[0004] Furthermore, although adding extra structures can suppress vortex intensity and improve cooling efficiency, it will also significantly increase the manufacturing cost of turbine blades and make them more difficult to process.

[0005] In addition, if the spanwise coverage of the air film is to be increased by reducing the size of the air film cooling holes within a limited spanwise dimension, it will also increase the machining difficulty of the turbine blades, and the machining accuracy will be difficult to guarantee.

[0006] In summary, the classic cylindrical configuration of film cooling holes can no longer significantly improve film cooling efficiency and the coverage of the cooling film along the blade span. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a turbine blade film cooling hole structure based on the Rupert's Tear configuration, which can effectively weaken the kidney vortex intensity at the outlet of the film cooling hole, thereby improving the film cooling efficiency. At the same time, it can effectively improve the coverage of the cooling film in the blade spanwise direction. By increasing the cooling gas storage cavity, it can effectively improve the performance of film cooling when the mainstream changes drastically.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a turbine blade film cooling hole structure based on the Rupert's Tear configuration, comprising a straight pipe section, a diffuser section, and a water droplet section, wherein the straight pipe section, diffuser section, and water droplet section are arranged sequentially, the small-diameter end of the diffuser section is connected to the straight pipe section, the large-diameter end of the diffuser section is connected to the water droplet section, and the connection between the diffuser section and the water droplet section is a smooth transition; the air inlet of the straight pipe section serves as the air inlet of the film cooling hole, the air outlet of the water droplet section serves as the air outlet of the film cooling hole, and the inner chamber of the air outlet of the water droplet section forms a cooling air buffer chamber.

[0009] The straight pipe section is inclined, and the central axis of the straight pipe section forms an angle of 30° to 40° with the tangent of the cooled plane or the cooled curved surface of the turbine blade. This angle is the intake angle.

[0010] The diameter of the straight pipe section is set as D1, and D1≤5mm.

[0011] The axial length of the straight pipe section is set as L1, and L1≥3D1.

[0012] The diffuser section has a curvature, and the axial length of the diffuser section is set as L2, where L2 = 2.5D1 to 3D1.

[0013] The maximum diameter of the water droplet segment is set as D3, and D3 = 1.8D1 ~ 2D1.

[0014] The axial length of the water droplet segment is set as L3, and L3 = 2.5D1 to 3D1.

[0015] The total axial length of the diffusion section and the droplet section is 5.5D1.

[0016] The beneficial effects of this invention are:

[0017] The turbine blade film cooling hole structure based on the Rupert's Tear configuration of the present invention can effectively weaken the kidney vortex intensity at the outlet of the film cooling hole, thereby improving the film cooling efficiency. At the same time, it can effectively improve the coverage of the cooling film in the blade spanwise direction. By increasing the cooling gas storage cavity, it can effectively improve the performance of film cooling when the mainstream changes drastically. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the turbine blade film cooling hole structure based on the Rupert's Tear configuration of the present invention (view 1);

[0019] Figure 2 This is a schematic diagram of the turbine blade film cooling hole structure based on the Rupert's Tear configuration of the present invention (perspective 2);

[0020] Figure 3The temperature distribution diagram of the cooled surface of the turbine blade, obtained through simulation test, is shown for the turbine blade film cooling hole structure based on Rupert's Tear configuration of the present invention.

[0021] Figure 4 Temperature distribution diagram of the cooled surface of a turbine blade obtained through simulation experiment for a classic cylindrical air film cooling hole structure;

[0022] In the diagram, I—straight pipe section, II—diffuser section, III—water droplet section, and A—cooling gas buffer chamber. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 , 2 As shown, a turbine blade film cooling hole structure based on the Rupert's Tear configuration includes a straight pipe section I, a diffuser section II, and a teardrop section III. The straight pipe section I, diffuser section II, and teardrop section III are arranged sequentially. The small-diameter end of the diffuser section II is connected to the straight pipe section I, and the large-diameter end of the diffuser section II is connected to the teardrop section III. The connection between the diffuser section II and the teardrop section III is a smooth transition. The air inlet of the straight pipe section I serves as the air inlet of the film cooling hole, and the air outlet of the teardrop section III serves as the air outlet of the film cooling hole. The inner chamber of the air outlet of the teardrop section III forms a cooling air buffer chamber A.

[0025] The straight pipe section I is inclined, and the central axis of the straight pipe section I forms an angle of 30° to 40° with the tangent of the cooled plane or the cooled curved surface of the turbine blade. This angle is the intake angle.

[0026] The diameter of the straight pipe section I is set as D1, and D1≤5mm.

[0027] The axial length of the straight pipe section I is set as L1, and L1≥3D1.

[0028] The diffuser section II has a curvature, and the axial length of the diffuser section II is set as L2, where L2 = 2.5D1 to 3D1.

[0029] The maximum diameter of the water droplet segment III is set as D3, and D3 = 1.8D1 ~ 2D1.

[0030] The axial length of the water droplet segment III is set as L3, and L3 = 2.5D1 to 3D1.

[0031] The total axial length of the diffusion section II and the water droplet section III is 5.5D1.

[0032] The following describes a single use of the present invention with reference to the accompanying drawings:

[0033] In this embodiment, the design method for the turbine blade film cooling hole structure based on the Rupert's Tear configuration is as follows:

[0034] Step 1: First, determine the total axial length of the film cooling holes, and assume that the straight pipe section I, the diffuser section II, and the water droplet section III are coaxially distributed and the diffuser section II has no curvature in the initial state. Then, use spline curves in the drawing software to draw the generatrix of the film cooling holes in the initial state.

[0035] Step 2: In the drawing software, select the central axis of the film cooling hole, and rotate the generatrix around the central axis to form a three-dimensional model of the film cooling hole without curvature.

[0036] Step 3: In the drawing software, bend the 3D model of the air film cooling hole that does not have curvature, and only select the diffuser section II for bending. When bending the diffuser section II, it is necessary to keep the perpendicular distance between each point on the hole wall surface of the diffuser section II and the central axis unchanged until a 3D model of the air film cooling hole with the set curvature is formed.

[0037] Step 4: Combine the established 3D model of the film cooling hole with the set curvature with the 3D model of the turbine blade. Ensure that the central axis of the water droplet section III is parallel to the tangent of the cooled plane or the cooled curved surface of the turbine blade and the mainstream direction. The water droplet section III intersects with the outer wall of the turbine blade to form the air outlet, and the straight pipe section I intersects with the inner wall of the turbine blade to form the air inlet. At the same time, ensure that the central axis of the straight pipe section I forms an angle of 30° to 40° with the tangent of the cooled plane or the cooled curved surface of the turbine blade, that is, the air inlet angle is within the set range.

[0038] Step 5: Optimize the distance between the central axis of water droplet segment III and the tangent of the cooled plane or the cooled curved surface through numerical simulation experiments, and select the distance with the best cooling effect under the design conditions.

[0039] When the turbine blade adopts the turbine blade film cooling hole structure based on the Rupert's Tear configuration of the present invention, the cooling gas first enters the straight pipe section I from the inlet and is rectified in the straight pipe section I. Then it enters the diffuser section II for deceleration and then enters the water droplet section III. A part of the cooling gas is directly ejected from the outlet to form a cooling gas film on the outer wall surface of the turbine blade. Another part of the cooling gas will first pass through the cooling gas buffer chamber A, and then leave the cooling gas buffer chamber A under the jet entrainment effect. Finally, it is also ejected from the outlet and works together with the part of cooling gas that is directly ejected from the outlet to cool the turbine blade.

[0040] When the turbine blades utilize the turbine blade film cooling hole structure based on the Rupert's Tear configuration of the present invention for film cooling, the intensity of the kidney vortex at the outlet can be effectively reduced, thereby increasing the spanwise coverage of the film. Since a cooling gas buffer cavity A is formed in the teardrop segment III, the presence of the cooling gas buffer cavity A can effectively improve the performance of film cooling when the mainstream changes drastically.

[0041] To better illustrate the superiority of the Rupert's Tear-based turbine blade film cooling hole structure over the classic cylindrical film cooling hole structure, simulation experiments were conducted on both under the same blowing ratio and mainstream conditions. Specific simulation results are as follows: Figure 3 and Figure 4 As shown, in Figure 3 As can be seen, the turbine blade film cooling hole structure based on the Rupert's Tear configuration of this invention achieves a significant reduction in the intensity of the kidney-shaped vortex at the outlet of the film cooling hole, and the spanwise distribution range of the cooling film is also significantly expanded, thereby further improving the film cooling efficiency. In contrast, the classic cylindrical film cooling hole structure... Figure 4 As can be seen, a relatively obvious kidney-shaped vortex is formed at the outlet of the air film cooling hole, and the longitudinal distribution range of the cooling air film is also narrower, which seriously restricts the improvement of air film cooling efficiency.

[0042] The solutions described in the embodiments are not intended to limit the scope of patent protection of this invention. All equivalent implementations or modifications that do not depart from the scope of this invention are included in the patent scope of this case.

Claims

1. A turbine blade film cooling hole structure based on Rupert's Tear configuration, characterized in that: The turbine blade comprises a straight pipe section, a diffuser section, and a water droplet section, arranged sequentially. The smaller diameter end of the diffuser section connects to the straight pipe section, and the larger diameter end connects to the water droplet section, with a smooth transition at the junction. The air inlet of the straight pipe section serves as the air inlet for the film cooling holes, and the air outlet of the water droplet section serves as the air outlet for the film cooling holes. The inner chamber of the water droplet section's outlet forms a cooling air buffer chamber. The straight pipe section is inclined, with its central axis forming a 30°–40° angle with the tangent of the cooled plane or curved surface of the turbine blade; this angle is the air inlet angle. The diameter of the straight pipe section is defined as D1, and D1 ≤ 5 mm. The axial length of the straight pipe section is defined as L1, and L1 ≥ 3D1. The diffuser section has curvature, and its axial length is defined as L2. The maximum diameter of the water droplet section is set to D3, and D3 = 1.8D1 ~ 2D1; the axial length of the water droplet section is set to L3, and L3 = 2.5D1 ~ 3D1; the total axial length of the diffuser section and the water droplet section is 5.5D1; the cooling gas first enters the straight pipe section from the inlet and is rectified in the straight pipe section, then enters the diffuser section for deceleration, and then enters the water droplet section. A portion of the cooling gas is directly ejected from the outlet to form a cooling gas film on the outer wall of the turbine blade. Another portion of the cooling gas first passes through the cooling gas buffer chamber, then leaves the cooling gas buffer chamber under the jet entrainment effect, and finally is also ejected from the outlet, and works together with the portion of cooling gas ejected directly from the outlet to cool the turbine blade.

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