Damage-resistant blade structure of steam turbine

Abstract

The invention provides a damage-resistant blade structure of a steam turbine, particularly relates to the technical field of steam turbines, and is used for solving the obvious technical defects of a current traditional steam turbine blade system under complex working conditions. The device comprises blades, a connection damping module, a through-flow corrosion prevention module, a sealing protection module and a monitoring integration module, and all the modules are cooperatively assembled in the axial direction and the circumferential direction of a steam turbine rotor to form an integrated damage-resistant structure. According to the structure, through collaborative design and precise assembly of all the modules, the remarkable technical defects of a traditional turbine blade system under the complex working condition can be effectively overcome.

Description

Technical Field

[0001] This invention relates to the field of steam turbine technology, and more specifically, to a steam turbine anti-damage blade structure. Background Technology

[0002] As the core power equipment in thermal power generation, the turbine's blade system directly undertakes the critical functions of steam energy conversion and power transmission. Operating under complex conditions of high temperature, high pressure, high speed, and steam erosion, it is a core component prone to unit failures. Current traditional turbine blade system structural designs still face the following critical technical challenges in areas such as fatigue damage resistance, steam erosion prevention, sealing efficiency, and condition monitoring: Current traditional steam turbine blade systems have significant technical shortcomings under complex operating conditions: In terms of blade shape, there is high stress concentration at the blade root connection, the segmented welding of the last-stage blades is prone to failure, and there is no effective protection in the high-temperature section and the low-pressure section lacks anti-erosion design, leading to frequent fatigue failures; the connection damping structure has poor adaptability, the damping effect of loose metal and separate shroud is limited, the thermal expansion of the overall disc easily leads to increased clearance, and the simple expansion joint lacks secondary sealing, which exacerbates corrosion and vibration; the flow path anti-corrosion design is imperfect, the last stage lacks an efficient dehumidification structure, resulting in severe erosion, and the fixed radial clearance is difficult to adapt to the operating conditions, easily leading to leakage or friction; the sealing structure has low efficiency, the independent comb-type steam seal has a large clearance and poor wear resistance, lacks coordinated design, and the coating is easy to peel off. Summary of the Invention

[0003] The purpose of this invention is to provide a turbine blade structure that is resistant to damage, which can solve the defects of existing turbine blade systems.

[0004] The embodiments of the present invention are achieved through the following technical solutions: A turbine blade anti-damage structure includes blades, a connection damping module, a flow path anti-corrosion module, a sealing protection module, and a monitoring integration module. These modules are assembled collaboratively along the axial and circumferential directions of the turbine rotor to form an integrated anti-damage structure. The specific connection relationships are as follows: The blade root is circumferentially adapted to the rotor hub to form a stress-relieving connection structure; the blade profile extends along the blade profile axis, and the blade crown is fixed to the top of the blade profile and forms an annular assembly surface along the rotor circumference. The connecting damping module's shroud is circumferentially fitted to the blade crown, and the lattice is radially inserted between the blade profiles of adjacent blades. The coupling structure between the rotor and the blade is fixed axially between the rotor disk and the blade profile to achieve vibration suppression and thermal expansion compensation. The dehumidification channel of the flow-through corrosion prevention module is set along the flow path on the steam inlet side of the last stage blade, and the adaptive gap adjustment structure is assembled along the radial gap between the blade tip and the cylinder inner wall. The steam seal of the sealing and protection module is arranged along the rotor axis on the inner wall of the cylinder and is embedded in the edge structure of the rotor to form a double seal. The built-in sensors of the monitoring integration module are embedded along the surface of the high-stress area of ​​the blade, and the stress monitoring grooves are opened on the wheel disk, corresponding to the sensor positions, so as to realize real-time monitoring of the high-stress area.

[0005] In some embodiments, the blade root is a multi-toothed arc blade root, and the multi-tooth structure is symmetrically distributed along the blade root axis, forming an interference fit with the wheel groove of the rotor hub; the inner wall of the wheel groove is provided with an elastic compensation groove along the circumferential direction, and the elastic compensation groove corresponds to the tooth gap of the multi-toothed arc blade root, so that the connection surface between the blade root and the hub forms a stress relief space.

[0006] In some embodiments, the blade profile is a variable cross-section anti-vibration blade profile, with the cross-sectional profile gradually changing from the blade root to the blade crown along the blade axial direction; the last stage blade adopts a hollow integrated forging structure, with at least one reinforcing rib provided axially inside, and the two ends of the reinforcing rib are respectively fixed to the inner wall of the blade; the blade crown and the blade profile are integrally formed, and a damping cavity is provided circumferentially inside the blade crown, and an elastic alloy sheet is assembled inside the damping cavity, with the two ends of the elastic alloy sheet abutting against the inner wall of the damping cavity.

[0007] In some embodiments, the hollow, integrally forged final stage blade is provided with a cooling steam channel inside. The inlet end of the cooling steam channel is connected to the high-pressure side of the turbine's steam path, and the outlet end is connected to the low-pressure side of the steam path, so that the cooling steam flows along the internal channel of the blade and covers the entire inner wall of the blade.

[0008] In some embodiments, the shroud of the connecting damping module is an integral blade crown structure, and damping plates are provided on the sides of the blade crowns of adjacent blades; the pull plate is an internal rigid pull plate, which is inserted radially into the preset channel of the blade shape, and the two ends of the pull plate are respectively fixed to the inner wall of the channel of the adjacent blade, and the axis of the pull plate is parallel to the axis of the blade crown damping cavity, forming a synergistic damping system.

[0009] In some embodiments, the coupling structure between the rotor and the blade adopts a composite fixing method of hydraulic expansion and laser sealing: during hydraulic expansion, after the blade root is inserted into the wheel groove of the wheel disk, high-pressure oil is injected through the pre-set expansion hole of the wheel disk to make the inner wall of the wheel groove and the blade root form an interference fit; laser sealing is performed along the axial joint between the blade root and the wheel groove, and the weld is continuously distributed along the circumference of the wheel groove; the wheel disk is a fan-shaped split structure, and thermal expansion compensation joints are reserved between the radial end faces of adjacent fan-shaped wheel disks, and the compensation joints are evenly distributed along the circumference of the wheel disk.

[0010] In some embodiments, the dehumidification channel of the flow-through corrosion prevention module is a centrifugal separation structure. The channel inlet is radially opened along the flow path on the steam inlet side of the last stage blade. The inner wall of the channel is provided with a spiral guide groove along the circumference. The guide groove is spirally distributed from the channel inlet to the outlet. The adaptive gap adjustment structure includes an elastic wear-resistant block. The elastic wear-resistant block is fixed to the end face of the blade tip and forms an annular protrusion along the circumference of the blade. The outer end face of the elastic wear-resistant block forms an adaptively adjustable radial gap with the inner wall of the cylinder.

[0011] In some embodiments, the gas seal of the sealing protection module is an integrated structure of elastic sheet and wear-resistant alloy layer. The elastic sheet is arranged in multiple layers along the rotor axis, and the wear-resistant alloy layer is coated on the surface of the elastic sheet facing the blade. The rotor extends radially outward to form a sealing boss. The radial contour of the sealing boss is adapted to the inner contour of the gas seal elastic sheet, so that the sealing boss is embedded between two adjacent layers of elastic sheet to form a double sealing fit.

[0012] In some embodiments, the built-in sensor of the monitoring integration module is a fiber optic grating sensor. The sensor is embedded in a miniature mounting groove opened along the surface of the blade root transition fillet. The miniature mounting groove extends along the blade axis and the groove opening is flush with the blade surface. The stress relief groove of the wheel is opened radially along the wheel. The strain gauge integrated in the groove is integrally formed with the wheel. The detection end of the strain gauge faces the high stress area where the wheel and the blade are connected, and the signal line of the strain gauge extends along the inner wall of the stress relief groove to the outer side of the wheel.

[0013] In some embodiments, the high-temperature section blade adopts a single-crystal structure, and the surface is covered with an in-situ nitriding protective layer along the axial and circumferential directions. The protective layer and the blade profile are metallurgically bonded. The low-pressure section blade is made of duplex steel. The vulnerable areas of the blade, namely the steam inlet edge and the blade tip, are provided with a biomimetic microtexture structure. The microtexture is a micron-level groove array uniformly distributed along the blade surface, and the biomimetic microtexture structure and the blade profile are integrally formed.

[0014] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects: 1. This invention significantly reduces stress concentration at the blade root and blade vibration amplitude through stress relief design of multi-toothed arc blade root and wheel groove elastic compensation groove, hollow integrated forging of the last stage blade, and synergistic damping system of blade crown damping cavity, thereby reducing fatigue cracks, weld cracks and other faults and extending blade service life; the differentiated design of single crystal structure and in-situ nitriding protective layer in high-temperature section, and dual-phase steel and biomimetic micro-texture in low-pressure section further enhances the material's resistance to degradation and the erosion resistance of vulnerable areas.

[0015] 2. The hydraulic expansion joint and laser sealing welding composite fixing method of the coupling structure between the rotor and the blade in this invention, combined with the thermal expansion compensation seam of the fan-shaped split wheel, adapts to temperature deformation and avoids the increase of gap; the built-in rigid pull metal, the blade crown damping plate and the damping cavity form synergistic damping, suppressing blade vibration in multiple dimensions and reducing the risk of swerving noise and vibration damage.

[0016] 3. In this invention, the centrifugal separation dehumidification channel can effectively separate water droplets in the steam and reduce the erosion of the last stage blades; the elastic wear-resistant block at the tip of the blade enables the radial clearance to be adaptively adjusted, avoiding friction and collision while reducing steam leakage; the optimized flow path design reduces flow field turbulence and helps improve the aerodynamic efficiency of the steam turbine.

[0017] 4. This invention reduces the steam seal gap and improves wear resistance by integrating the elastic sheet and wear-resistant alloy layer into a steam seal and the rotor sealing boss for a double sealing fit. This significantly reduces high-pressure steam leakage, reduces energy waste and the risk of blade erosion in the low-pressure section, and reduces secondary failures such as coating peeling.

[0018] 5. In this invention, the fiber optic grating sensor embedded in the high-stress area of ​​the blade and the high-temperature resistant strain gauge integrally formed in the stress relief groove of the rotor disk enable real-time monitoring of the high-stress area, avoid signal interference and monitoring deviation problems of external sensors, provide early warning of potential faults in the blade and rotor disk, and ensure the safe and reliable operation of the unit. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is an internal sectional view of a turbine damage-resistant blade structure installed in a turbine, as provided in an embodiment of the present invention. Figure 2 This is a cross-sectional view of the blades being mounted around the rotor according to an embodiment of the present invention; Figure 3 for Figure 1 A magnified view of part A in the middle; Figure 4 This is a schematic diagram of the structure of two adjacent blades provided in an embodiment of the present invention; Figure 5 This is a side sectional view of the blade provided in an embodiment of the present invention; Figure 6 This is a cross-sectional view of the last-stage blade provided in an embodiment of the present invention.

[0021] Icons: 1. Blade root; 2. Hub; 3. Wheel groove; 4. Elastic compensation groove; 5. Last stage blade; 6. Hollow cavity; 7. Reinforcing rib; 8. Blade crown; 9. Blade shape; 10. Damping cavity; 11. Elastic alloy sheet; 12. Cooling steam channel; 13. Damping sheet; 14. Laggar; 15. Wheel disc; 16. Compensation joint; 17. Expansion joint hole; 18. Dehumidification channel; 19. Elastic wear-resistant block; 20. Elastic sheet; 21. Sealing boss; 22. Miniature mounting groove; 23. Fiber optic grating sensor; 24. Stress relief groove; 25. Strain gauge. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] In the description of this invention, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0026] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Please see Figures 1-6 As shown, the main body of this embodiment is a turbine anti-damage blade structure, which is suitable for medium and large capacity thermal power generation turbines. It is assembled sequentially from the high-pressure cylinder to the low-pressure cylinder along the turbine rotor axis. Each module works in a logical coordination manner with blade type 9 as the core, connection damping as support, flow path corrosion prevention as protection, sealing protection as assurance, and monitoring integration as early warning, forming a complete anti-damage optimization system.

[0028] During the overall assembly, the wheel 15 is first spliced ​​and fixed along the axial direction. Then, the blades are connected to the wheel 15 through a coupling structure to achieve a stable connection. Subsequently, the connection damping module, flow-through corrosion prevention module, and sealing protection module are assembled in sequence. Finally, the sensor of the monitoring integration module is embedded and the signal line is connected to ensure that the functions of each module are coordinated and the structure is compatible.

[0029] Furthermore, the blade includes a blade root 1 and a hub 2. The blade root 1 adopts a multi-tooth arc structure with symmetrical arc teeth. During machining, the surface of the blade root 1 is precision milled using a five-axis CNC machine tool to ensure that the surface roughness meets aerodynamic and assembly requirements. The hub 2's groove 3 precisely matches the multi-tooth structure of the blade root 1. The inner wall of the groove 3 is circumferentially formed with an elastic compensation groove 4 using electrical discharge machining. The width of the compensation groove is consistent with the gap between the teeth of the blade root 1, and the depth is designed to not weaken the overall structural strength of the hub 2.

[0030] During assembly, the blade root 1 is smoothly pressed into the wheel groove 3 by a hydraulic device to form an interference fit. The elastic compensation groove 4 can effectively absorb the stress generated between the blade root 1 and the wheel hub 2 during the assembly process and operation, thus avoiding local stress concentration.

[0031] Furthermore, the blade profile 9 adopts a variable cross-section vibration-resistant design. The gradual curve of the cross-section profile from the blade root 1 to the blade crown 8 is optimized and determined by aerodynamic simulation software to ensure a balance between aerodynamic performance and vibration resistance during blade operation. The blade profile 9 is manufactured using an integral forging followed by CNC milling to ensure that the dimensional deviation of the blade profile 9 meets the design accuracy requirements. The last-stage blade 5 adopts a hollow integrated forging process. During the forging process, a pre-set hollow cavity 6 is formed through an internal mold. Subsequently, at least one axial reinforcing rib 7 is welded inside the hollow cavity 6. The material of the reinforcing rib 7 is consistent with that of the blade profile 9. The two ends of the reinforcing rib 7 are connected to the inner wall of the blade using a full welding process. After welding, the weld area is subjected to ultrasonic penetrant non-destructive testing to ensure that there are no welding defects such as incomplete fusion or cracks.

[0032] Both the blade crown 8 and the blade profile 9 are integrally forged to avoid deformation problems caused by subsequent welding. The damping cavity 10 is milled along the circumferential direction inside the blade crown 8. The cross-section of the damping cavity 10 can be designed as rectangular or trapezoidal. An elastic alloy sheet 11 is installed in the cavity. The elastic alloy sheet 11 is made of an alloy with high elasticity and high temperature resistance, such as Inconel 718. The two ends of the elastic alloy sheet 11 are fixed to the inner wall of the damping cavity 10 by spot welding to ensure that the elastic alloy sheet 11 can adapt to the vibration of the blade during operation, consume vibration energy and suppress vibration.

[0033] Furthermore, the cooling steam passage 12 of the last-stage blade 5 is formed using a drilling and milling composite machining process. The inlet end of the passage is located at the blade root near the turbine disk 15, and is connected to the high-pressure side of the turbine's steam path via a pipe. The outlet end of the passage is located at the blade tip near the blade crown 8, and is connected to the low-pressure side of the steam path. The inner wall of the passage needs to be polished to ensure smooth flow of cooling steam within the passage and that the cooling steam can cover the entire inner wall of the blade, achieving effective cooling of the blade and reducing the operating humidity on the blade surface.

[0034] Furthermore, the connecting damping module includes a shroud and damping plates 13. The shroud adopts an integral structure that surrounds the outer end of the blade crown 8. The circumferential contact surfaces of the blade crowns 8 of adjacent blades are precision ground using a surface grinder to ensure that the flatness of the contact surfaces meets the requirements for tight fit. Damping plates 13 are provided on the sides of adjacent blade crowns 8. The damping plates 13 are made of materials with high friction coefficient and high temperature resistance, such as copper-based alloys or graphite-based composite materials. The damping plates 13 are firmly bonded and fixed to the contact surfaces of the blade crowns 8 using a high-temperature adhesive. After assembly, they fit tightly against the blade crowns 8. The damping plates 13 can generate frictional damping when the blade vibrates, effectively suppressing the vibration amplitude of the blade.

[0035] Furthermore, the built-in rigid lamellar plate 14 is made of stainless steel with high temperature resistance and wear resistance, such as 1Cr11MoV, and is machined into a cylindrical or square cross-section. The surface is chrome-plated to improve wear resistance. A drilling machine is used to machine channels at preset positions on the blade profile 9, with the channel axis parallel to the axis of the damping cavity 10 on the blade crown 8. After inserting the lamellar plate 14 into the channel of the adjacent blade, both ends of the lamellar plate 14 are fixed to the inner wall of the channel using argon arc welding. After welding, the weld area is ground to ensure that the weld does not affect the flow of steam on the blade surface. The lamellar plate 14, damping plate 13, and damping cavity 10 work synergistically to construct a multi-damping system, further reducing the blade vibration amplitude.

[0036] Furthermore, the rotor disc 15 adopts a fan-shaped split structure, which is formed by forging. Thermal expansion compensation joints 16 are pre-reserved on the radial end faces of adjacent fan-shaped rotor discs 15 to accommodate temperature changes during unit start-up, shutdown, and operation. During assembly, the fan-shaped rotor discs 15 are first spliced ​​along the rotor axis and then connected and fixed using flanges and bolts. Flexible high-temperature resistant sealing material, such as ceramic fiber, is filled into the thermal expansion compensation joints 16 to prevent steam leakage from the compensation joints 16.

[0037] The blade is fixed to the wheel disk 15 using a combination of hydraulic expansion and laser sealing. During the hydraulic expansion stage, high-pressure oil is injected into the expansion holes 17 opened radially on the wheel disk 15, causing plastic deformation of the inner wall of the wheel groove 3, achieving a tight fit with the blade root 1. After the expansion is completed, laser sealing is performed along the axial joint between the blade root 1 and the wheel groove 3. The weld is continuously distributed around the wheel groove 3, achieving both sealing and fixing functions, and preventing the blade from loosening during operation.

[0038] Furthermore, the flow-through corrosion prevention module includes a centrifugal separation dehumidification channel 18. The dehumidification channel 18 is located on the cylinder inner wall on the steam inlet side of the last-stage blade 5, and is formed using casting and milling processes. The inlet of the dehumidification channel 18 is radially opened along the flow path, and the inlet direction forms a preset angle with the steam flow direction, thereby ensuring that steam can smoothly enter the channel. The inner wall of the dehumidification channel 18 is circumferentially machined with spiral guide grooves, which are spirally distributed from the inlet to the outlet. After steam enters the channel, under the action of centrifugal force, water droplets in the steam are thrown towards the inner wall of the channel and flow along the spiral guide grooves to the drain outlet. The drain outlet is connected to the condenser, and the dried steam enters the moving blade flow area from the channel outlet, reducing the erosion of the blades by water droplets.

[0039] Furthermore, the adaptive clearance adjustment structure includes an elastic wear-resistant block 19, made of an alloy with high hardness and wear resistance. It is fixed to the end face of the blade tip using argon arc welding, employing a segmented welding process to control welding deformation. After welding, the surface of the wear-resistant block is ground to ensure a continuous annular protrusion along the blade circumference. The initial radial clearance between the outer end face of the elastic wear-resistant block 19 and the cylinder inner wall is set according to the unit's cold operating conditions. During operation, the wear-resistant block undergoes slight deformation due to the thermal expansion and vibration of the blade, automatically compensating for clearance changes. This avoids direct friction between the blade and the cylinder inner wall and reduces steam leakage from the clearance.

[0040] Furthermore, the sealing protection module includes an integrated steam seal, which adopts an integrated structure of elastic sheet 20 plus a wear-resistant alloy layer. The elastic sheet 20 is made of stainless steel with high elasticity and corrosion resistance, such as 1Cr18Ni9Ti, and is processed by stamping. It is arranged in multiple layers along the rotor axis, the number of layers being determined according to the unit's sealing requirements. The radial spacing between adjacent elastic sheets 20 remains uniform. A wear-resistant alloy layer is coated on the side of the elastic sheet 20 facing the blades using a plasma spraying process. The wear-resistant alloy layer is made of WCCo alloy. After spraying, the surface of the wear-resistant alloy layer is ground to ensure that the surface flatness of the coating meets the design requirements.

[0041] The steam seal is fixed to the steam seal groove on the inner wall of the cylinder by bolts. During the assembly process, the gap between the steam seal and the blade needs to be adjusted to ensure that the gap value meets the requirements for sealing and safe operation.

[0042] Furthermore, the blade sealing boss 21 includes a sealing boss formed by the rotor extending radially outward. The cross-section of the sealing boss 21 can be designed as trapezoidal or rectangular, and is formed by milling. The radial height of the boss is adapted to the number of layers of the steam seal elastic sheet 20. After assembly, the sealing boss 21 is embedded between two adjacent layers of steam seal elastic sheet 20, forming a double sealing structure of sealing boss 21 and elastic sheet 20. Steam must pass through the gap between the elastic sheet 20 and the gap between the boss in sequence, which greatly increases the steam leakage resistance and reduces the amount of steam leakage.

[0043] Furthermore, a miniature mounting groove 22 is created at the transition radius of the blade root 1 using laser processing. The groove opening is flush with the blade surface to avoid affecting the blade's aerodynamic performance. The fiber optic grating sensor 23 is embedded in the mounting groove, and a high-temperature resistant adhesive is filled between the sensor and the groove wall. After the adhesive has cured, the groove opening is polished.

[0044] Furthermore, the stress relief groove 24 of the wheel 15 is milled radially along the wheel 15, and the groove depth and width are determined according to the structural strength requirements of the wheel 15 and the size of the strain gauge 25. The strain gauge 25 is selected as a high-temperature resistant type and is fixed in the stress relief groove 24 by an integral molding process. The detection end of the strain gauge 25 faces the high-stress area where the wheel 15 connects with the blade, ensuring accurate acquisition of stress data in the high-stress area. The signal line of the strain gauge 25 extends along the wire hole on the inner wall of the stress relief groove 24 to the junction box on the outside of the wheel 15, and connects to the external monitoring system to realize real-time monitoring of the stress state of the wheel 15.

[0045] Furthermore, during the processing of high-temperature blades, after the single-crystal structure is forged, an in-situ nitriding protective layer is formed on the blade surface through a gas nitriding process. The protective layer is metallurgically bonded to the blade profile 9, covering the entire axial and circumferential regions of the blade. For vulnerable areas such as the steam inlet edge and blade tip of the low-pressure dual-phase steel blade, after the blade profile 9 is milled, a biomimetic micro-texture structure is processed through a laser texturing process. A pulsed laser is used to etch a micron-level groove array on the blade surface. The grooves extend along the steam flow direction or the circumferential direction of the blade and are integrally formed with the blade profile 9, without the need for additional processing afterward.

[0046] Through the collaborative design and precise assembly of its modules, this structure can achieve the following technical effects: Enhanced damage resistance: The combined design of the multi-toothed arc blade root 1, the integrated blade crown 8, and the multiple damping system can effectively reduce blade vibration and local stress concentration, and significantly extend the blade fatigue life. Optimized corrosion resistance: The centrifugal separation dehumidification channel 18 can reduce the water droplet content in the steam, and the elastic wear-resistant block 19 and the blade surface protection structure can improve the blade's resistance to erosion and reduce the blade's corrosion rate. Sealing and efficiency improvement: The dual sealing structure of "elastic sheet 20 + sealing boss 21" can significantly reduce steam leakage, reduce steam energy loss, and improve the relative internal efficiency of the steam turbine. Improved monitoring accuracy: The built-in fiber optic grating sensor 23 and strain gauge 25 can collect real-time status data of the high-stress areas of the blade and the impeller 15, providing rapid early warning response and effectively avoiding sudden failures.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present 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 turbine blade structure for damage resistance, characterized in that, The turbine includes blades, a connecting damping module, a flow-through corrosion prevention module, a sealing protection module, and a monitoring integration module. These modules are assembled axially and circumferentially along the turbine rotor to form an integrated, damage-resistant structure. The specific connection relationships are as follows: The blade root (1) is circumferentially adapted to the rotor hub (2) to form a stress-relieving connection structure; the blade shape (9) extends along the axial direction of the blade shape (9), and the blade crown (8) is fixed to the top of the blade shape (9) and forms an annular assembly surface along the rotor circumference; The connecting damping module's shroud is circumferentially fitted to the blade crown (8), and the laminar flow (14) is radially inserted between the blade profiles (9) of adjacent blades. The coupling structure between the rotor and the blade is fixed axially between the rotor disk (15) and the blade profile (9) to achieve vibration suppression and thermal expansion compensation. The dehumidification channel (18) of the flow-through corrosion prevention module is set along the flow path on the steam inlet side of the last stage blade (5), and the adaptive gap adjustment structure is assembled along the radial gap between the blade tip and the cylinder inner wall. The steam seal of the sealing and protection module is arranged along the rotor axis on the inner wall of the cylinder and is embedded in the edge structure of the rotor to form a double seal. The built-in sensor of the monitoring integration module is embedded along the surface of the high stress area of ​​the blade, and the stress monitoring groove is opened on the wheel disk (15) to correspond to the position of the sensor so as to realize real-time monitoring of the high stress area.

2. The turbine damage-resistant blade structure according to claim 1, characterized in that, The blade root (1) is a multi-tooth circular arc blade root (1), and the multi-tooth structure is symmetrically distributed along the axial direction of the blade root (1), forming an interference fit with the wheel groove (3) of the rotor hub (2); the inner wall of the wheel groove (3) is provided with an elastic compensation groove (4) along the circumferential direction, and the elastic compensation groove (4) corresponds to the tooth gap of the multi-tooth circular arc blade root (1), so that the connection surface between the blade root (1) and the hub (2) forms a stress relief space.

3. The turbine damage-resistant blade structure according to claim 1, characterized in that, The blade profile (9) is a variable cross-section anti-vibration blade profile (9), and the cross-sectional profile gradually changes from the blade root (1) to the blade crown (8) along the blade axis; the last stage blade (5) adopts a hollow integrated forging structure, and at least one reinforcing rib (7) is provided in the interior along the axis, and the two ends of the reinforcing rib (7) are respectively fixed to the inner wall of the blade; the blade crown (8) and the blade profile (9) are integrally formed, and a damping cavity (10) is provided in the interior of the blade crown (8) along the circumferential direction. An elastic alloy sheet (11) is assembled in the damping cavity (10), and the two ends of the elastic alloy sheet (11) abut against the inner wall of the damping cavity (10).

4. The turbine damage-resistant blade structure according to claim 3, characterized in that, The hollow integrated forged final stage blade (5) is provided with a cooling steam channel (12). The inlet end of the cooling steam channel (12) is connected to the high-pressure side of the steam passage of the turbine, and the outlet end is connected to the low-pressure side of the steam passage, so that the cooling steam flows along the internal channel of the blade and covers the entire inner wall of the blade.

5. The turbine damage-resistant blade structure according to claim 1, characterized in that, The connecting damping module is a whole blade crown (8) structure, and damping plates (13) are provided on the sides of the blade crown (8) of adjacent blades; the puller (14) is a built-in rigid puller (14), which is inserted into the preset channel of the blade shape (9) along the radial direction of the blade. The two ends of the puller (14) are fixed to the inner wall of the channel of the adjacent blade, and the axis of the puller (14) is parallel to the axis of the damping cavity (10) of the blade crown (8), forming a synergistic damping system.

6. The turbine damage-resistant blade structure according to claim 1, characterized in that, The coupling structure between the rotor and the blade adopts a composite fixing method of hydraulic expansion and laser sealing: during hydraulic expansion, after the blade root (1) is inserted into the wheel groove (3) of the wheel disk (15), high-pressure oil is injected through the pre-set expansion hole (17) of the wheel disk (15) so that the inner wall of the wheel groove (3) and the blade root (1) form an interference fit; laser sealing is carried out along the axial joint between the blade root (1) and the wheel groove (3), and the weld is continuously distributed along the circumference of the wheel groove (3); the wheel disk (15) is a fan-shaped split structure, and a thermal expansion compensation joint (16) is reserved between the radial end faces of adjacent fan-shaped wheel disks (15), and the compensation joint (16) is evenly distributed along the circumference of the wheel disk (15).

7. The turbine damage-resistant blade structure according to claim 1, characterized in that, The dehumidification channel (18) of the flow-through corrosion prevention module is a centrifugal separation structure. The channel inlet is radially opened along the flow path on the steam inlet side of the last stage blade (5). The inner wall of the channel is provided with a spiral guide groove along the circumference. The guide groove is spirally distributed from the channel inlet to the outlet. The adaptive gap adjustment structure includes an elastic wear-resistant block (19). The elastic wear-resistant block (19) is fixed to the end face of the blade tip and forms an annular protrusion along the circumference of the blade. The outer end face of the elastic wear-resistant block (19) forms an adaptively adjustable radial gap with the inner wall of the cylinder.

8. The turbine damage-resistant blade structure according to claim 1, characterized in that, The sealing protection module's steam seal is an integrated structure of an elastic sheet (20) and a wear-resistant alloy layer. The elastic sheet (20) is arranged in multiple layers along the rotor axis, and the wear-resistant alloy layer is coated on the side surface of the elastic sheet (20) facing the blade. The rotor extends radially outward to form a sealing boss (21). The radial contour of the sealing boss (21) is adapted to the inner contour of the steam seal elastic sheet (20), so that the sealing boss (21) is embedded between two adjacent layers of elastic sheets (20) to form a double sealing fit.

9. The turbine damage-resistant blade structure according to claim 1, characterized in that, The built-in sensor of the monitoring integration module is a fiber optic grating sensor (23). The sensor is embedded in a micro mounting groove (22) opened at the transition rounded corner of the blade root (1). The micro mounting groove (22) extends along the blade axis and the groove opening is flush with the blade surface. The stress relief groove (24) of the wheel (15) is opened radially along the wheel (15). The strain gauge (25) integrated in the groove is integrally formed with the wheel (15). The detection end of the strain gauge (25) faces the high stress area where the wheel (15) is connected to the blade.

10. A turbine damage-resistant blade structure according to any one of claims 1-9, characterized in that, The high-temperature section blade adopts a single crystal structure, and the surface is covered with an in-situ nitriding protective layer along the axial and circumferential directions. The protective layer and the blade shape (9) are metallurgically combined. The low-pressure section blade is made of duplex steel. The vulnerable areas of the blade, namely the steam inlet edge and the blade tip, are provided with a biomimetic micro-texture structure. The micro-texture is a micron-level groove array evenly distributed along the blade surface, and the biomimetic micro-texture structure and the blade shape (9) are integrally formed.

Images