Steam turbine blade with air guide structure

Abstract

This utility model discloses a turbine blade with a wind-guiding structure, comprising: an integrally formed blade and a blade root connected in sequence; a plurality of positive guide grooves extending along the blade height direction are provided on the front side of the blade, and a plurality of back guide grooves extending along the blade height direction are provided on the back side of the blade; the positive and back guide grooves are arranged alternately in the blade span direction and at an angle α to the tangent of the blade profile; the outer diameter opening edges of the positive and back guide grooves are provided with serrated teeth. This structure, through the synergistic effect of the inclined grooves on both sides and the outer diameter teeth, forms near-wall directional wind guidance and multi-scale dispersion of the wake, suppressing separation and secondary flow, reducing main frequency pulsation and noise, improving interstage energy utilization, and expanding the stable operating range.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine blade technology, specifically a steam turbine blade with an air guiding structure. Background Technology

[0002] When turbine blades operate under a wide range of conditions, the incoming flow angle of attack, Reynolds number, and outlet pressure pulsations constantly change. This leads to thickening, separation, and secondary flow in the near-wall layers of the pressure and suction surfaces. Furthermore, leakage vortices and strong wake vortex chains are superimposed at the outer diameter end, resulting in aerodynamic losses, increased noise, and a narrowing of the stable operating range. In engineering practice, it is typically desirable to introduce controllable tangential velocity components and re-energy conversion mechanisms in the near-wall region of the blades. This allows the near-wall flow to converge directionally and mix thoroughly with the mainstream, while simultaneously rapidly dispersing the wake at the outer diameter end.

[0003] Existing technologies mainly include the following types of solutions: (1) Smooth surface + integral coating: Reduce surface friction and erosion by depositing corrosion-resistant / hydrophobic coatings on the entire blade or in parts. This type of solution helps with initial wear, but does not provide directional guidance for near-wall flow, makes it difficult to suppress separation and wake frequency pulsation, and has limited efficiency improvement.

[0004] (2) Single-sided straight or short groove texture: A straight groove or a local short groove that is basically parallel to the tangential direction of the profile is opened on one side of the pressure or suction surface to disturb the boundary layer. Since there is no coordinated configuration on both sides, and the groove-mainstream angle is close to zero and the groove depth / width remains unchanged along the blade height, the guiding capacity is weak, and "channelized" boundary layer and additional drag increment are easy to occur; the adaptability at different blade heights is poor.

[0005] (3) Only set sawtooth / notch at the outer diameter end: rely on the toothed edge at the outer diameter end to disperse the wake. This type of structure is not geometrically matched with the blade guide, the inner near-wall flow still lacks organized transport, and the wake still exhibits a strong dominant frequency vortex train.

[0006] In summary, existing solutions generally have the following shortcomings: lack of wind-guiding geometry that links the front and back sides, making it difficult to establish a continuous and stable near-wall flow channel across the entire blade height; the angle between the guide slot arrangement and the tangential of the profile is often insufficient, and the slot depth / width does not gradually change with the blade height, resulting in limited energy supply and mixing effects; the outer diameter end lacks a toothed diffusion design that coordinates with the outflow from the guide slot, and the wake vortex is still large-scale and has a strong dominant frequency.

[0007] Therefore, there is an urgent need for a guide groove system that is staggered on the front and back of the blade and forms a set angle with the tangent of the blade profile. The guide grooves should increase along the blade height parameters and be distributed with differentiated density according to the leading and trailing edge regions. A serrated tooth should be configured at the outer diameter end to work with the outflow inside the groove to disperse the wake. At the same time, geometric consistency should be ensured through integral molding and finishing, and durability should be improved by combining corrosion-resistant / hydrophobic coatings. This will solve the problems of insufficient flow guidance, strong wake pulsation, and poor manufacturing consistency. Utility Model Content

[0008] This utility model aims to solve one of the technical problems existing in the prior art or related technologies.

[0009] Therefore, the technical solution adopted by this utility model is as follows: a turbine blade with an air guiding structure, comprising an integrally formed blade 100 and a blade root 200. The front side of the blade 100 is provided with several positive guide grooves 110 extending along the blade height direction, and the back side is provided with several back guide grooves 120 extending along the blade height direction; the positive and back guide grooves are staggered in the blade span direction and arranged at an angle α tangential to the blade profile; each guide groove forms a serrated tooth 130 at its outer diameter end opening edge. A controllable tangential velocity field is formed by the staggered oblique grooves on both sides, which, in conjunction with the outer diameter end teeth, disperses the wake at multiple scales, thereby obtaining stable near-wall air guiding and diffusion capabilities.

[0010] The blade 100 is provided with a front guide groove 110 and a back guide groove 120 on its front and back sides, respectively. The front and back guide grooves are staggered in the blade span direction and arranged at an angle α with the tangent to the profile. The outer diameter end opening edge of each guide groove forms a serrated tooth 130.

[0011] In a preferred example, the blade is further configured such that the positive guide groove 110 is offset toward the trailing edge, the negative guide groove 120 is offset toward the leading edge, and the toothed opening 130 is continuously arranged along the blade span direction.

[0012] Specific technical effects: The staggered and obliquely placed guide channels on both sides introduce stable tangential momentum input in the near-wall layer, which promotes the directional migration of the near-wall flow and its mixing with the mainstream; the 130mm outer diameter toothed opening splits the large-scale wake vortex, reduces the main frequency pulsation and noise, and achieves geometric synergy between wind guidance and diffusion.

[0013] In a preferred example, the included angle α is set to 10° to 45°; the positive guide groove 110 and the back guide groove 120 are respectively inclined from the end near the leaf root 200 to the end away from the leaf root.

[0014] Specific technical effects: The appropriate angle ensures an effective tangential velocity component between the guide channel and the main flow, while taking into account both root strength and outer diameter air guiding capacity; the inclined setting along the blade height creates a continuously enhanced air guiding effect from the root to the outer diameter.

[0015] In a preferred example, the cross-sections of the forward guide groove 110 and the back guide groove 120 are U-shaped, V-shaped, or rounded trapezoidal, and the groove depth and groove width increase along the blade height direction.

[0016] Specific technical effects: The increasing cross-section and size along the flow path creates capacity expansion and energy replenishment, reduces local pressure drop and additional resistance, avoids secondary separation, and ensures continuous and effective airflow channels.

[0017] In a preferred example, the total number of positive guide grooves 110 and back guide grooves 120 is 6 to 24; the pitch of adjacent guide grooves decreases or remains constant along the blade height direction from the root side to the outer diameter end.

[0018] Specific technical effects: The parameterized setting of quantity and pitch ensures uniform airflow coverage and avoids interference between slots, balancing airflow capacity, strength and manufacturability.

[0019] In a preferred example, the positive guide groove 110 has a higher density near the trailing edge of the blade 100 than near the leading edge; the negative guide groove 120 has a higher density near the leading edge of the blade 100 than near the trailing edge. The increased density is achieved by reducing the pitch or increasing the number of guide grooves, with the transition zone employing a linear or piecewise linear variation.

[0020] Specific technical effects: Differentiated reinforcement is implemented for easily separable areas of the pressure surface and suction surface to improve reattachment capability and reduce local losses.

[0021] In a preferred embodiment, the front and back guide slots are further configured such that they are staggered relative to each other in the middle of the blade 100 via a transition zone, and the ends of the guide slots in the transition zone have a rounded corner with a radius of R0.3 to 1.0 mm. Furthermore, the width of the metal bridge between adjacent ends is not less than 0.8 mm.

[0022] Specific technical effects: staggered and rounded transitions avoid sudden interference caused by the outflow from both sides, reduce stress concentration, and improve the overall reliability of the blades.

[0023] In a preferred example, the blade 100 and the blade root 200 are integrally cast or formed by powder metallurgy, and the guide groove and tooth area are machined or laser remilled.

[0024] Specific technical effects: One-piece molding ensures overall strength and consistency, and subsequent finishing ensures the dimensional accuracy and surface quality of the air guide geometry, resulting in stable batch aerodynamic performance.

[0025] In a preferred embodiment, the blade 100 is further configured such that at least one of a hard corrosion-resistant coating or a hydrophobic coating is applied to the vicinity of the forward guide groove 110, the back guide groove 120, and the tooth 130.

[0026] Specific technical effects: The hard layer improves erosion resistance and wear resistance, while the hydrophobic layer inhibits deposition and wetting. The two work together to maintain the long-term air guiding and diffusion effect of the guide groove and tooth opening, thus extending service life.

[0027] The beneficial effects achieved by this utility model are as follows: 1. In this invention, the forward guide groove 110 and the backward guide groove 120 are staggered in the blade span direction and arranged tangentially to the blade profile at an included angle α. The cross-section and dimensions of the guide grooves increase along the blade height, and their density is configured according to leading / trailing edge zones. This introduces a stable tangential velocity component in the near-wall region of the blade and forms a continuous airflow channel, promoting boundary layer reattachment and weakening separation and secondary flow. The outer diameter end teeth 130 further disperse the detached vortices and enhance mixing and diffusion, significantly reducing wake frequency pulsation and noise. This improves interstage energy utilization and aerodynamic efficiency, and expands the range of stable operating conditions.

[0028] 2. In this invention, the blade 100 and the blade root 200 are integrally formed, and the guide groove and tooth area are machined / laser finished. A hard corrosion-resistant coating or a hydrophobic coating can be applied to the area adjacent to the guide groove and tooth. This integrated structure allows parameters to be flexibly set according to level and operating conditions, ensuring batch consistency and manufacturability. The coating and finished surface improve erosion resistance and anti-fouling ability, maintaining air guiding effect and surface integrity for a long time, thereby improving blade durability and reducing maintenance costs. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present utility model; Figure 2 This is a schematic diagram of the back structure of the blade according to an embodiment of the present invention.

[0030] Figure label: 100. Blade; 110. Positive guide groove; 120. Negative guide groove; 130. Tooth; 200. Leaf root. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features of the present utility model can be combined with each other.

[0032] It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this invention.

[0033] The following describes, with reference to the accompanying drawings, some embodiments of the present invention, providing a turbine blade with an air guiding structure.

[0034] Combination Figures 1-2As shown, the present invention provides a turbine blade with a wind-guiding structure, which is composed of an integrally formed blade 100 and a blade root 200. The front side of the blade 100 is provided with several positive guide grooves 110 along the blade height direction, and the back side of the blade 100 is provided with several back guide grooves 120 along the blade height direction. The positive guide grooves 110 and the back guide grooves 120 are arranged alternately in the blade span direction and at an angle α relative to the profile of the blade 100. Each guide groove has a serrated edge 130 at its outer diameter end, with the angle α ranging from 10° to 45°. The positive guide grooves 110 and the back guide grooves 120 are respectively inclined along the blade height direction from the end closer to the blade root 200 to the end farther from the blade root 200.

[0035] The aforementioned airflow guidance geometry, through the synergy of "inclined guide grooves + outer diameter toothed openings," constructs a near-wall flow directional guidance and wake dispersion structure, which is suitable for medium and low-pressure turbine blades.

[0036] Working effect: Under operating conditions, the incoming flow migrates along the outer diameter direction of the channel under the action of the tangential component velocity of the guide channel. The toothed end 130 of the outer diameter will split the shedding vortex and promote mixing and diffusion, thereby suppressing separation / secondary flow and main frequency wake pulsation, and improving aerodynamic efficiency and operating stability.

[0037] In this embodiment, the positive guide groove 110 and the back guide groove 120 are respectively inclined from one end near the blade root 200 to the end away from the blade root: the positive guide groove 110 is offset towards the trailing edge relative to the tangential direction of the profile, and the back guide groove 120 is offset towards the leading edge relative to the tangential direction of the profile, so as to form complementary wind velocity fields on both sides.

[0038] Specific technical effects: The oblique angle provides stable tangential momentum input, prompting the near-wall flow to reattach and mix with the mainstream, thus weakening the different stall trends of the pressure / suction side.

[0039] In this embodiment, the cross-sections of the forward guide groove 110 and the back guide groove 120 can be U-shaped, V-shaped, or rounded trapezoidal. To achieve flow-width expansion and drag reduction, the groove depth and width increase progressively along the blade height direction. One feasible parameter is: Specific technical effects: The small cross-section at the root facilitates the convergence of near-wall flow without weakening the matrix strength, while the cross-section with gradually increasing outer diameter reduces pressure drop along the flow path and improves the flow conduction capacity, avoiding local Mach number spikes and secondary separation.

[0040] In this embodiment, the total number of forward guide grooves 110 and back guide grooves 120 is 6 to 24. To accommodate different blade heights and spanwise widths, the pitch of adjacent guide grooves can be designed to decrease along the blade height direction or remain constant. For example, the pitch decreases linearly from 4.0 mm to 2.5 mm from the root to the outer diameter along the blade height direction; alternatively, they can be arranged at equal intervals of 3.0 mm.

[0041] Specific technical effects: Reasonable quantity and pitch ensure uniform airflow coverage and avoid mutual interference, guaranteeing the continuity of airflow and the manufacturability of strength.

[0042] In this embodiment, the density of the positive guide groove 110 is higher near the trailing edge of the blade 100 than near the leading edge; the density of the back guide groove 120 is higher near the leading edge of the blade 100 than near the trailing edge. The density can be adjusted by changing the pitch or increasing the number of guide grooves.

[0043] Specific technical effects: Differentiated enhancement is implemented for the different characteristics of the pressure surface (where turbulent boundary layer thickening is easily generated near the trailing edge) and the suction surface (where local separation is easily generated near the leading edge), guiding near-wall flow reattachment and weakening typical detached vortices.

[0044] In this embodiment, to avoid opposing interference between the two guide slots in the middle, the front guide slot 110 and the back guide slot 120 are staggered relative to each other in the middle of the blade 100 through a transition zone. The ends of the guide slots in the transition zone are finished with a rounded corner of R0.3 to 1.0 mm; a metal bridge width of not less than 0.8 mm is maintained between the ends of adjacent guide slots to ensure structural strength.

[0045] Specific technical effects: staggered arrangement and rounded ends reduce flow abrupt changes and local stress concentration, improving the overall reliability and manufacturability of the blades.

[0046] In this embodiment, the blade 100 and the blade root 200 are preferably integrally cast or formed by powder metallurgy; the guide groove and tooth area are finished by five-axis CNC precision machining, electrical discharge machining or laser remilling.

[0047] Specific technical effects: ensuring geometric consistency and surface quality between the guide groove and the toothed edge, and stabilizing the aerodynamic performance and fatigue life of batch parts.

[0048] To improve durability and anti-deposition capabilities, the blade 100 may be coated with at least one of the following in the vicinity of the forward guide groove 110, the back guide groove 120, and the tooth 130: hard corrosion-resistant coating: such as CrN, AlTiN, DLC-H, etc., with a thickness of 10 to 60 μm; hydrophobic coating: such as fluorosilane self-assembled film or DLC thin film, with a thickness of 0.2 to 2.0 μm.

[0049] The coating can be achieved using processes such as PVD / HVOF / PECVD, and is preferentially applied to the bottom of the guide groove and the windward side of the tooth opening. The hard layer resists particle erosion and droplet impact, while the hydrophobic layer reduces wetting and fouling. Together, they maintain long-term airflow efficiency and surface integrity.

[0050] Working mechanism: During unit operation, the incoming flow is directionally transported from the root to the outer diameter along the guide slot under the drive of the tangential momentum of the guide slot; the increasing cross section realizes the expansion of the flow range and energy replenishment, and weakens the boundary layer separation; the staggered distribution on both sides establishes a complementary guide field; the 130mm outer diameter toothed notch splits the large-scale vortex of the wake into a multi-scale vortex street and enhances mixing and diffusion, reducing the main frequency pulsation and noise. As a result, the aerodynamic efficiency and operational stability of the blades are improved over a wide operating range.

[0051] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A steam turbine blade with an air guiding structure, characterized in that, include: The blade (100) and the leaf root (200) are connected in sequence. The front side of the blade (100) is provided with a plurality of positive guide grooves (110) extending along the blade height direction, and the back side of the blade (100) is provided with a plurality of back guide grooves (120) extending along the blade height direction; each of the positive guide grooves (110) and the back guide grooves (120) are arranged alternately in the blade span direction and are arranged at an angle α to the tangent of the blade (100) profile line; each of the positive guide grooves (110) and the back guide grooves (120) has a serrated tooth (130) at the outer diameter end opening edge.

2. The blade according to claim 1, characterized in that, The included angle α is 10° to 45°, and the positive guide groove (110) and the back guide groove (120) are respectively inclined along the leaf height direction from the end near the leaf root (200) to the end away from the leaf root (200).

3. The blade according to claim 1, characterized in that, The cross-sections of the positive guide groove (110) and the back guide groove (120) are U-shaped, V-shaped or rounded trapezoidal, and the groove depth and groove width of each guide groove increase in the direction of blade height.

4. The blade according to claim 1, characterized in that, The total number of the positive guide groove (110) and the back guide groove (120) is 6 to 24. The pitch of adjacent guide grooves decreases or remains constant from the root side to the outer diameter end along the blade height direction.

5. The blade according to claim 1, characterized in that, The density of the positive guide groove (110) near the leading edge of the blade (100) is lower than that near the trailing edge, and the density of the back guide groove (120) near the trailing edge of the blade (100) is lower than that near the leading edge.

6. The blade according to claim 1, characterized in that, The positive guide groove (110) and the back guide groove (120) are arranged opposite each other in the middle of the blade (100) through a transition zone, and the end of the guide groove in the transition zone adopts a rounded transition of R0.3~1.0 mm.

7. The blade according to claim 1, characterized in that, The blade (100) and the blade root (200) are integrally cast or integrally formed by powder metallurgy, and the positive guide groove (110), the back guide groove (120) and the toothed area (130) are machined or laser remilled.

8. The blade according to claim 1, characterized in that, The blade (100) is coated with at least one of a hard corrosion-resistant coating or a hydrophobic coating in the vicinity of the positive guide groove (110), the back guide groove (120), and the tooth (130).

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