A method and device for dry in-situ magnetic control repair of water turbine blade cavitation erosion

Abstract

This invention discloses a method and apparatus for dry in-situ magnetically controlled repair of cavitation erosion on turbine blades. The method includes: after the turbine is shut down and the accumulated water is drained to create a dry environment, a repair actuator is inserted into the flow channel through a manhole in the volute and moved to the cavitation erosion area on the blade surface; geometric feature data of the cavitation erosion area is collected, and a thixotropic composite repair material containing magnetic particles is prepared; the composite repair material is injected into the cavitation erosion area according to the geometric feature data, and a controllable magnetic field is applied, using the magnetic force to drive the magnetic particles to migrate, thereby making the material dense and compacted and conforming to the blade profile; the compacted composite repair material is cured, and the repair actuator is withdrawn after reaching a preset strength. This invention enables unmanned in-situ repair of cavitation erosion areas on turbine blades, significantly shortening the maintenance cycle and reducing safety risks. The magnetic field compaction technology improves the density of the repair material and the bonding strength with the matrix, effectively ensuring the repair quality.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower equipment maintenance and condition-based maintenance technology, and in particular to a dry in-situ magnetic control repair method and device for turbine blade cavitation. Background Technology

[0002] When hydroelectric turbines operate under long-term high head and high flow velocity conditions, cavitation (cavitation) is prone to occur in localized areas on the blade surface, forming pitted or pitted damage. If the cavitation areas are not repaired in time, they will gradually expand and cause damage to the blade profile. This not only leads to a significant decrease in the hydraulic performance of the turbine but also causes safety hazards such as reduced blade structural strength, seriously affecting the safe and stable operation of the turbine unit and the power generation efficiency of the hydroelectric power station.

[0003] Currently, the methods for repairing cavitation erosion of turbine blades used in engineering are mainly divided into two categories: disassembly and overhaul, and manual in-situ repair. Both have obvious technical defects and application limitations, making it difficult to adapt to the actual needs of lean operation and maintenance of hydropower stations.

[0004] The disassembly and overhaul method requires the entire turbine unit to be disassembled, and the runner is lifted out. The blades are then ground, welded, or sprayed for repair in the maintenance workshop. Although this method can ensure high repair quality, it has the problems of long downtime and complex disassembly and assembly procedures. It not only causes huge power generation losses, but also generates high maintenance and labor costs. It is only suitable for major overhaul scenarios with severe blade damage.

[0005] Manual in-situ repair can be carried out after a short unit shutdown and drainage of water from the volute and runner chamber. Workers enter the flow channel to manually grind, weld, or apply epoxy mortar to the cavitation areas of the blades. This method, which does not require disassembly, makes it suitable for minor and temporary repairs. However, in practical applications, it has several shortcomings. The flow channel is narrow, humid, and presents harsh working conditions, posing a high safety risk. Manual application of repair materials makes it difficult to ensure the compactness of the material filling the cavitation area and the smoothness of the blade surface, resulting in poor profile matching after repair and affecting turbine operating efficiency. Welding repairs can easily introduce thermal stress into the blade substrate, causing damage to the substrate material and reducing the reliability of the blade structure. For cavitation areas of a certain depth and volume, manual operation is difficult to achieve effective filling and compaction, leading to delamination and peeling of the repair layer, resulting in poor durability.

[0006] In addition, existing automated spraying or surface protection technologies are mainly used for thin-layer protection of blade surfaces, which can only achieve surface repair of minor cavitation erosion. They cannot reliably fill and structurally repair cavitation erosion areas with a certain depth and volume, making it difficult to meet the actual needs of deep repair of cavitation erosion areas in engineering.

[0007] In summary, existing repair technologies cannot simultaneously meet the practical engineering requirements of eliminating the need for dismantling the turbine, enabling unmanned operation within the flow channel, precisely filling cavitation areas, and achieving high-density molding of the repair layer. Therefore, there is an urgent need to develop an in-situ repair technology for turbine blade cavitation that is suitable for short-term shutdown maintenance scenarios in hydropower stations. This technology should achieve precise and dense filling and structural repair of cavitation areas without dismantling the turbine or requiring personnel to enter the flow channel. This would ensure repair quality and durability while shortening downtime and reducing maintenance costs, thus meeting the practical application requirements of lean operation and maintenance in hydropower stations. Summary of the Invention

[0008] The main objective of this invention is to provide a dry in-situ magnetic control repair method for cavitation of turbine blades.

[0009] Another objective of this invention is to provide a dry in-situ magnetically controlled repair device for cavitation of turbine blades.

[0010] The third objective of this invention is to provide a computer device.

[0011] A fourth objective of this invention is to provide a non-transitory computer-readable storage medium.

[0012] To achieve the above objectives, a first aspect of the present invention provides a dry in-situ magnetic control repair method for cavitation erosion of turbine blades, comprising:

[0013] After the turbine is shut down and the accumulated water is drained to create a dry environment, the repair actuator is inserted into the flow channel through the manhole of the volute and moved to the cavitation area on the blade surface. Geometric feature data of the cavitation area were collected, and a thixotropic composite repair material containing magnetic particles was prepared. The composite repair material is injected into the cavitation area according to the geometric feature data, and a controllable magnetic field is applied to drive the magnetic particles to migrate so that the material is compacted and fits the blade profile. The compacted composite repair material is cured until it reaches a preset strength, at which point the repair actuator is removed.

[0014] In one embodiment of the present invention, after the turbine is shut down and the accumulated water is drained to form a dry environment, the repair actuator is inserted into the flow channel through the volute manhole and moved to the cavitation erosion area on the blade surface, comprising: The multi-degree-of-freedom telescopic robotic arm is fixed at the manhole door of the turbine casing, and the integrated repair head is installed at the end of the multi-degree-of-freedom telescopic robotic arm. The control terminal drives the multi-degree-of-freedom telescopic robotic arm to extend into the turbine flow channel along the inside of the volute, and adjusts the posture of the integrated repair head to reach the surface of the turbine blade. The integrated repair head is moved to the cavitation area on the blade surface to complete the installation and positioning of the repair actuator.

[0015] In one embodiment of the present invention, the preparation of the thixotropic composite repair material containing magnetic particles includes: Modified epoxy resin or polyurethane resin is selected as the matrix material of component A, and a curing agent that matches the matrix material is selected as component B. Magnetic particles are added to components A and B, wherein the magnetic particles are carbonyl iron powder or ferrite magnetic powder. Wear-resistant aggregates and thixotropic agents are added and mixed to obtain a magnetic polymer composite repair material that is thixotropic paste after mixing.

[0016] In one embodiment of the present invention, collecting geometric feature data of the cavitation erosion region includes: The contour, depth, and volume of the cavitation erosion area on the blade surface are scanned and measured using the three-dimensional scanning module in the integrated repair head. Obtain the location, depth, and volume information of the cavitation erosion area, and build a three-dimensional model of the cavitation erosion area based on this information; The three-dimensional model is used to calculate the amount of repair material needed, and geometric feature data for controlling the injection amount is obtained.

[0017] In one embodiment of the present invention, the step of injecting the composite repair material into the cavitation erosion area according to the geometric feature data and applying a controllable magnetic field to drive the magnetic particles to migrate so that the material is compacted and conforms to the blade profile includes: After the A component and B component are mixed instantly by the mixing and injection module, they are quantitatively injected into the cavitation area according to the geometric feature data, filling it to a level slightly higher than the blade surface. The electromagnetic compaction module in the integrated repair head is activated to generate a local high-intensity magnetic field. The magnetic force is applied to the magnetic particles in the injected composite repair material, guiding the magnetic particles to accumulate towards the blade matrix, thereby achieving densification of the repair material and eliminating internal air bubbles. Based on the fine-tuning of the robotic arm's posture, the flat surface of the repair head is made to fit with the blade profile. The flat surface of the repair head is then used to fit with the blade profile to perform magnetic shaping and repair, resulting in a repair layer that matches the original blade profile.

[0018] In one embodiment of the present invention, the curing treatment of the compacted composite repair material includes: Activate the auxiliary curing module in the integrated repair head to heat or irradiate the repair area, so that the composite repair material reaches its initial setting strength; Once the composite repair material reaches the preset strength, the curing process is completed and the repair actuator is ready to be withdrawn.

[0019] In one embodiment of the present invention, the step of draining the accumulated water after the turbine is shut down to create a dry environment includes: Close the turbine inlet valve, drain the water from the spiral casing and runner chamber, and open the spiral casing manhole. After a short shutdown and draining the water from the volute and impeller chamber, no manual entry into the flow channel is required; instead, a robotic arm can be used to extend into the flow channel for the operation. Confirm that the volute and impeller chamber meet the requirements for dry environment conditions, satisfying the requirement for in-situ repair without disassembling the impeller.

[0020] To achieve the above objectives, a second aspect of the present invention provides a dry in-situ magnetically controlled repair device for cavitation erosion of turbine blades, comprising: A multi-degree-of-freedom telescopic robotic arm is installed at the manhole or inspection port of the turbine casing to extend into the runner flow channel along the inside of the casing. Its end can be adjusted to reach the surface of the turbine blades. An integrated repair head, installed at the end of the multi-degree-of-freedom telescopic robotic arm, integrates a three-dimensional scanning module, a mixing and spraying module, an electromagnetic compaction module, and an auxiliary curing module. It is used to complete the scanning measurement of the cavitation area, the injection of repair material, magnetic field compaction, and curing treatment. A repair material supply system, connected to the integrated repair head, is used to store and transport thixotropic composite repair material containing magnetic particles; The control terminal, located outside the volute, is used for centralized control of the robotic arm's movement, scanning data, material injection volume, electromagnetic field strength, and curing process.

[0021] To achieve the above objectives, a third aspect of this application provides a computer device comprising a processor and a memory; wherein the processor reads executable program code stored in the memory to run a program corresponding to the executable program code, for implementing a dry in-situ magnetic control repair method for cavitation of turbine blades as described in the first aspect embodiment.

[0022] To achieve the above objectives, the fourth aspect of this application proposes a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements a dry in-situ magnetic control repair method for cavitation of turbine blades as described in the first aspect embodiment.

[0023] The embodiments of the present invention have the following beneficial effects: This invention enables blade cavitation repair without disassembling the turbine unit, significantly shortening the unit's maintenance cycle and effectively reducing power generation losses due to downtime. It aligns with the lean operation and maintenance needs of hydropower stations. Furthermore, the entire process eliminates the need for personnel to enter the spiral casing and flow channels, fundamentally avoiding safety hazards associated with confined and humid working environments and significantly reducing the safety risks of maintenance operations. Simultaneously, relying on magnetic field compaction technology to drive the migration and enrichment of magnetic particles within the repair material significantly increases the material's density, enhances the bonding strength between the repair layer and the blade's metal matrix, and ensures stable and reliable repair quality. Moreover, the injection and curing of the repair material are completed in a dry environment, with fully controllable curing conditions. The resulting repair layer possesses excellent wear resistance and cavitation resistance, effectively extending the service life of the repaired blade. In addition, the repair process of this invention is highly adaptable and can be applied to the cavitation repair of blades for various turbine types, demonstrating good technical versatility and promising engineering promotion value and practical application prospects. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 A flowchart of a dry in-situ magnetic control repair method for cavitation of turbine blades provided in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the repair principle provided in an embodiment of the present invention; Figure 3 This is a structural diagram of a dry in-situ magnetically controlled repair device for cavitation of turbine blades provided in an embodiment of the present invention; Figure 4 A schematic diagram of the overall structure of a dry in-situ magnetically controlled repair device system for cavitation of turbine blades provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the cross-sectional structure of the turbine casing provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the integrated repair head structure provided in an embodiment of the present invention. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] The following describes, with reference to the accompanying drawings, a method and apparatus for dry in-situ magnetic control repair of cavitation in turbine blades according to an embodiment of the present invention.

[0028] Example 1 This embodiment provides a dry in-situ magnetic control repair method for cavitation erosion of turbine blades. Taking the repair operation of a mixed-flow turbine in a hydropower station as an example, this embodiment illustrates that the turbine blades have a cavitation erosion area with a diameter of approximately 30 mm and a depth of approximately 5 mm at the water outlet edge. This method can achieve efficient in-situ repair of this cavitation erosion area. Figure 1 As shown, the method includes the following steps: S1, after the turbine is shut down and the accumulated water is drained to form a dry environment, the repair actuator is inserted into the flow channel through the manhole of the volute and moved to the cavitation area on the blade surface.

[0029] Specifically, this step aims to create internal working conditions that do not require disassembly of the main unit. First, a dry working environment is established by sending a shutdown command from the control terminal to the turbine control system to close the turbine inlet valve and cut off the pressurized water supply. Then, the drainage pump set is started to drain the water accumulated in the spiral casing and runner chamber below the maintenance baseline. Operators open the manhole door of the spiral casing to open the maintenance passage, and then collect the internal air humidity data through the environmental monitoring module. The data is compared with the preset drying threshold to confirm that the spiral casing and runner chamber have reached the dry environment conditions, meeting the requirements for in-situ repair without disassembling the runner. The entire process is completed after a short shutdown, without the need for manual entry into the flow channels.

[0030] Further, after completing the dry environment construction, the repair actuator is erected, positioned, and extended. The base of the multi-degree-of-freedom telescopic robotic arm is fixed to the manhole door of the turbine casing using a sealing flange, and a sealing structure is set at the flange connection to ensure that the dry environment inside the casing is not damaged. At the same time, the integrated repair head is installed at the end interface of the robotic arm, completing the overall hardware assembly. Based on the motion planning data from the control terminal, motion commands are sent to drive the multi-degree-of-freedom telescopic robotic arm to extend into the turbine flow channel along the inside of the casing. The angles and extension lengths of each joint of the robotic arm are adjusted to ensure that the integrated repair head avoids obstacles on the inner wall of the flow channel and reaches the surface of the turbine blade after adjusting its posture. Then, through the fine-tuning mechanism at the end of the robotic arm, the central axis of the integrated repair head is aligned with the center of the cavitation erosion area according to the approximate location information of the cavitation erosion area, ensuring that the field of view of the subsequent scanning module covers the damaged area, and the relative position of the repair head and the cavitation erosion area is locked. Thus, the precise erection and positioning of the repair actuator is achieved, and the subsequent operation is ready.

[0031] This step, through a rigorous shutdown, drainage, and environmental verification process, combined with the application of an external multi-degree-of-freedom telescopic robotic arm, ensures that the repair work is carried out in a safe, dry environment, avoids the long downtime and high costs associated with the complete dismantling of the unit, and fundamentally eliminates the safety risks of personnel entering narrow, damp flow channels. The multi-degree-of-freedom adjustment capability of the robotic arm enables the repair head to accurately reach and position complex-shaped blades, providing a stable operating platform for subsequent in-situ magnetic control repair, effectively ensuring the accessibility and operational precision of the repair work.

[0032] S2, Collect geometric feature data of the cavitation area and prepare a thixotropic composite repair material containing magnetic particles.

[0033] Specifically, the core of this step is to accurately acquire spatial information of the area to be repaired and customize the repair medium with magnetic response characteristics, providing data support and material basis for subsequent quantitative filling and magnetic field compaction. When collecting geometric feature data of the cavitation area, the control terminal drives the multi-degree-of-freedom telescopic robotic arm to accurately align the three-dimensional scanning module in the integrated repair head with the cavitation area on the blade surface. The three-dimensional scanning module uses the emitted scanning beam and the received reflected signal as input to scan and measure the surface contour, depression depth, and spatial volume of the cavitation area. After internal data processing, point cloud data containing the location coordinates, maximum depth value, and total volume information of the cavitation area is generated, and a three-dimensional model of the cavitation area is established based on this.

[0034] The control system has a built-in calculation model for quantitative injection of repair materials, which automatically calculates the required pumping volume of repair materials according to the following formula. :

[0035] In the formula, The actual volume of the cavitation pit obtained from the 3D scan (3.5 cm³). The curing shrinkage rate of the material (the empirical value for the magnetic epoxy composite material used in this embodiment is 0.02); The volume compression ratio of the magnetic compaction degassing is the volume reduction caused by eliminating air bubbles inside and at the interface of the material (since the material has thixotropic properties, it is easy to trap microbubbles inside, so the empirical value is taken as 0.05). The surface shaping allowance is used to ensure that the flexible isolation layer of the electromagnetic compaction module can be fitted and shaped without material shortage (1.07 in this embodiment).

[0036] In summary, the control terminal automatically calculates the total amount of repair material required based on the pit volume information and a preset filling redundancy coefficient. For example, when the volume of the cavitation area is measured to be approximately 3.5 cm³, the control system automatically calculates and sets the pumping volume of approximately 4.0 cm³ of repair material, and outputs geometric feature data to control the injection volume, thereby realizing the quantitative calculation of the amount of repair material used.

[0037] Furthermore, the preparation of a thixotropic composite repair material containing magnetic particles is carried out simultaneously. Modified epoxy resin or polyurethane resin can be selected as the matrix material of component A, and a matching curing agent can be selected as component B. The components are mixed according to process requirements to form a basic resin system. Then, carbonyl iron powder or ferrite magnetic powder is added to the basic resin system as magnetic particles, and its mass is controlled to account for 20% to 40% of the total mass of the repair material, so as to ensure sufficient magnetic response and good fluidity. Subsequently, silicon carbide, corundum or tungsten carbide wear-resistant aggregate and fumed silica thixotropic agent are added. After stirring, the components are evenly dispersed, and finally a thixotropic paste-like magnetic polymer composite repair material is obtained. This material has good anti-sagging properties, is suitable for repair construction on complex locations such as blade vertical surfaces and top surfaces, and has uniformly distributed internal magnetic particles, which can achieve effective response and migration under the action of a subsequent magnetic field.

[0038] In this embodiment, a magnetic epoxy composite repair material is selected, namely, modified epoxy resin as component A matrix material, and a matching curing agent as component B, which are mixed according to process requirements to form a basic resin system; carbonyl iron powder is added to the basic resin system as magnetic particles, and its mass ratio is controlled to be 20%~40%; silicon carbide wear-resistant aggregate and fumed silica thixotropic agent are added, and after stirring and dispersing, a thixotropic paste-like magnetic epoxy composite repair material is obtained, which is suitable for the repair construction of the vertical surface of the blade water outlet edge.

[0039] This step, through 3D scanning modeling and automated dosage calculation, achieves digital quantification of the geometric features of the cavitation area, effectively avoiding errors in manual estimation. This ensures the compactness of subsequent filling, reduces material waste, and improves repair accuracy and efficiency. The customized thixotropic composite repair material not only solves the sagging problem in complex surface construction but also provides a key material basis for subsequent magnetic force-driven compaction through the reasonable ratio of magnetic particles. At the same time, the addition of wear-resistant aggregates and thixotropic agents further enhances the wear resistance and cavitation erosion resistance of the repair material, ensuring the bonding strength and service durability between the repair layer and the blade substrate.

[0040] S3, inject the composite repair material into the cavitation area according to the geometric feature data, and apply a controllable magnetic field to drive the magnetic particles to migrate so that the material is compacted and fits the blade profile.

[0041] like Figure 2 As shown, the core of this step is to achieve precise quantitative filling of the repair material in the cavitation erosion area and densification under magnetic field drive, while ensuring precise adhesion between the repair layer and the original blade profile. First, the control system reads the geometric feature data of the cavitation erosion area collected in the previous step and sends it to the mixing and injection module. The mixing and injection module calculates the required material volume based on this data, and immediately mixes the A and B components of the composite repair material into a thixotropic paste. Then, it pumps the repair material quantitatively into the cavitation erosion area to fill it until the filling height is slightly higher than the blade surface, forming a pre-filled repair body.

[0042] Subsequently, the electromagnetic compaction module in the integrated repair head is activated, applying a controllable local high-intensity magnetic field to the injected composite repair material. The magnetic field strength and energizing time of the electromagnetic compaction module are set based on the migration and compaction kinetics model of magnetic particles in thixotropic fluids. To achieve compaction of the material without flow (thixotropic state), the applied magnetic field yield stress is... It must be greater than the initial thixotropic yield stress of the material. The expression is:

[0043] in, The permeability of free space, The magnetization intensity of the magnetic particles inside the material. The magnetic field gradient is used. According to system calculations, when the mass fraction of carbonyl iron powder in the repair material is 20%~40%, a local magnetic induction intensity of at least 0.4T~0.5T needs to be generated on the surface of the repair head in order to overcome the viscous resistance of the epoxy matrix and pull the overall material to shrink densely towards the blade metal matrix.

[0044] Furthermore, the electromagnetic compaction module generates a magnetic field and is continuously energized. This magnetic force drives the magnetic particles within the material to oriented and rearrange towards the blade matrix, causing the entire repair material to shrink and compact. Simultaneously, internal air bubbles are eliminated, forming a dense repair material layer. The time required for magnetically controlled compaction... Depends on the depth of the cavitation pit Equivalent migration velocity of particles under the influence of a magnetic field The expression is:

[0045] in, The depth of the cavitation pit (5 in this embodiment) mm ), The apparent viscosity of the material. Relative permeability For magnetic induction intensity (0.5) T ), The average radius of the magnetic particles is given. The system calculates the time required for material densification and bubble removal based on pre-stored material properties. The theoretical time is approximately 8.5 minutes. To ensure thorough compaction and complete surface bonding and shaping, the control system provides a safety margin, setting the continuous voltage compaction time to 10 minutes.

[0046] Finally, based on the multi-degree-of-freedom telescopic robotic arm, the posture of the integrated repair head is finely adjusted so that the flat surface of the repair head fits tightly with the blade profile. Under the continuous action of the magnetic field, magnetic attraction-type shaping and repair are carried out, so that the surface of the compacted repair material is precisely matched with the original profile of the blade, and finally a repair layer that meets the hydraulic performance requirements of the turbine is formed, completing the glue injection filling and magnetic field compaction and leveling operation.

[0047] In this embodiment, the control system pumps approximately 4.0 cm³ of magnetic epoxy composite repair material into the cavitation area based on the geometric data of the cavitation area obtained by scanning. A 0.5T magnetic field is applied continuously for 10 minutes to complete the magnetic compaction and leveling, ultimately obtaining a repair surface consistent with the blade profile.

[0048] This step utilizes magnetic force to drive the directional migration of magnetic particles, significantly improving the internal density of the repair material, effectively eliminating air bubbles generated during the filling process, and significantly enhancing the bonding strength between the repair layer and the blade's metal substrate. Simultaneously, combined with magnetically controlled leveling and precise posture adjustment of the robotic arm, it ensures that the surface profile of the repair layer closely matches the prototype profile of the blade, completely solving the problems of insufficient flatness and poor profile matching caused by traditional manual application repair. This effectively restores the hydraulic performance of the blade and significantly improves the stability and consistency of the repair quality.

[0049] S4. The compacted composite repair material is cured, and the repair actuator is removed after the preset strength is reached.

[0050] Specifically, the core of this step is to achieve the shaping and curing of the repair material and the safe withdrawal of the repair actuator, which is accomplished through the auxiliary curing module in the integrated repair head. After the electromagnetic compaction module completes the dense compaction of the material in the cavitation area, the control terminal sends a curing start command to the integrated repair head. Upon receiving the command, the integrated repair head activates its built-in auxiliary curing module. This module can use an infrared heating lamp or an ultraviolet curing lamp to emit infrared thermal radiation or ultraviolet light waves to the repair area, continuously heating or irradiating the magnetic polymer composite repair material filling the cavitation area. The heating time data of the infrared heating module comes from the Arrhenius curing kinetic equation of polymer materials, the expression of which is:

[0051] in, To achieve the target heating temperature The time required to reach the initial strength; To be at room temperature The initial setting time of the material at 298K (i.e., 25℃) is approximately 12 hours (i.e., 720 minutes) at room temperature. To repair the activation energy of the curing reaction in the material system; It is the ideal gas constant; This refers to the constant curing temperature formed by the infrared heating module in the repair area.

[0052] The control system is configured to use an infrared heating module to raise and maintain the local temperature of the repaired area at 80℃ (353K). Based on the formula above, under 80℃ thermal excitation, the cross-linking reaction rate is significantly increased, achieving the curing time required for the device to achieve initial strength (Shore hardness > 80D). The curing time has been significantly reduced to approximately 28 minutes. To ensure reliable curing, the system is set to heat for 30 minutes using the infrared heating module. Once the material has cured, the equipment is removed, and the repair work is complete.

[0053] In this embodiment of the invention, the infrared heating module is activated to heat the repair area for 30 minutes. The external energy field stimulates the activity of the curing agent within the composite repair material, causing a cross-linking reaction in the matrix resin. This transforms the material from a thixotropic paste into a solid repair layer with structural support capabilities. During the curing process, the system continuously monitors or predicts the material's strength growth until its mechanical properties reach a preset strength sufficient to support the repair layer's own weight and the hydraulic load during the initial stages of operation. Once the material is confirmed to have cured completely and reached the preset strength, the control terminal deactivates the infrared heating module and generates a withdrawal permission signal. The repair actuator responds to this signal, controlling the multi-degree-of-freedom telescopic robotic arm to perform a withdrawal action, detaching from the repair area and exiting the flow channel through the volute manhole, completing the in-situ repair of the cavitation area.

[0054] This step utilizes an integrated auxiliary curing module, relying on infrared heating or ultraviolet light to accelerate the resin cross-linking reaction, enabling rapid shaping and strength building of the repair material in a dry environment. Simultaneously, based on preset strength, the timing of withdrawal is precisely controlled, effectively preventing deformation or detachment of the repair layer due to equipment removal before complete curing. This significantly improves the integrity and stability of the repair structure, further shortens the turbine shutdown and maintenance cycle, and reduces operation and maintenance costs.

[0055] Example 2 This invention also provides a dry in-situ magnetically controlled repair device for cavitation erosion of turbine blades, such as... Figure 3 As shown, the device includes: A multi-degree-of-freedom telescopic robotic arm is installed at the manhole or inspection port of the turbine casing to extend into the runner flow channel along the inside of the casing. Its end can be adjusted to reach the surface of the turbine blades.

[0056] like Figure 4 The diagram shown is a schematic representation of the overall structure of the device system. Figure 5 The diagram shows a cross-sectional view of the turbine volute. Specifically, a multi-degree-of-freedom telescopic robotic arm is installed at the manhole or inspection port of the turbine volute, used to extend into the runner flow channel along the inside of the volute. This robotic arm has multiple degrees of freedom, and its end effector can be flexibly adjusted to precisely reach the cavitation erosion area on the turbine blade surface. The movement of the robotic arm is controlled by a control terminal through a preset program or manual operation, ensuring precise positioning within the narrow flow channel space.

[0057] The integrated repair head, installed at the end of the multi-degree-of-freedom telescopic robotic arm, integrates a three-dimensional scanning module, a mixing and spraying module, an electromagnetic compaction module, and an auxiliary curing module. It is used to complete the scanning measurement of the cavitation area, the injection of repair material, magnetic field compaction, and curing treatment.

[0058] like Figure 6 The diagram shows a schematic of the integrated repair head structure. Specifically, the integrated repair head is installed at the end of the multi-degree-of-freedom telescopic robotic arm and integrates a three-dimensional scanning module, a mixing and spraying module, an electromagnetic compaction module, and an auxiliary curing module. It is used to complete the scanning measurement of the cavitation area, the injection of repair material, magnetic field compaction, and curing treatment.

[0059] The 3D scanning module is used to perform non-contact scanning and measurement of the cavitation erosion area on the blade surface after the robotic arm reaches the predetermined position, acquiring the contour, depth, and volume data of the cavitation erosion area. This module can use laser scanning or structured light scanning technology, enabling high-precision 3D topography acquisition in a short time.

[0060] The mixing and injection module is connected to the repair material supply system. It is used to instantly mix component A (modified epoxy resin or polyurethane resin) and component B (curing agent), and then quantitatively inject the mixture into the cavitation area based on the geometric feature data obtained by the 3D scanning module. This module has a precise metering function, which can ensure accurate filling of the repair material, and the surface of the material after filling is slightly higher than the original blade profile.

[0061] The electromagnetic compaction module is a small, powerful electromagnet with a flexible insulating layer on its surface. This layer generates a localized, high-intensity magnetic field after the repair material is injected. Under the influence of the magnetic field, magnetic particles (carbonyl iron powder or ferrite magnetic powder) in the repair material accumulate towards the blade matrix, causing the entire material to shrink and compact, while simultaneously eliminating internal air bubbles. By fine-tuning the posture of a robotic arm, the flat surface of the electromagnetic compaction module is aligned with the blade profile, achieving magnetically controlled leveling and resulting in a repair layer that matches the original blade profile.

[0062] The auxiliary curing module can be an infrared heating lamp or an ultraviolet curing lamp, used to heat or irradiate the compacted repair area to accelerate the curing process of the repair material and enable it to reach its initial setting strength in a shorter time.

[0063] A repair material supply system, connected to the integrated repair head, is used to store and transport thixotropic composite repair material containing magnetic particles.

[0064] Specifically, the repair material supply system is connected to the integrated repair head and is used to store and transport thixotropic composite repair material containing magnetic particles. The system includes an A-component storage tank, a B-component storage tank, a mixing and conveying pipeline, and a metering pump. According to instructions from the control terminal, it can transport the material to the mixing and spraying module of the integrated repair head according to a preset ratio.

[0065] The control terminal, located outside the volute, is used for centralized control of the robotic arm's movement, scanning data, material injection volume, electromagnetic field strength, and curing process.

[0066] Specifically, the control terminal is located outside the volute and is used for centralized control of the robotic arm's movement, scanning data, material injection volume, electromagnetic field strength, and curing process. The control terminal is equipped with a human-machine interface that can display the 3D scanning results of the cavitation area, the status of the repair material injection, the magnetic field strength, and the curing progress in real time. Operators can adjust various parameters as needed to achieve automated and precise control of the repair process.

[0067] This embodiment achieves unmanned, in-situ, magnetically controlled repair of turbine blade cavitation through the coordinated operation of the four core components. It eliminates the need to disassemble the runner and allow personnel to enter the flow channel, significantly improving repair efficiency and quality while reducing safety risks and maintenance costs.

[0068] Example 3 To implement the methods of the above embodiments, the present invention also provides a computer device, which includes a memory and a processor; wherein the processor runs a program corresponding to the executable program code by reading executable program code stored in the memory, so as to implement the various steps of the methods described above.

[0069] Example 4 To implement the above embodiments, this application also proposes a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the method described in the foregoing embodiments.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for dry in-situ magnetic control repair of cavitation erosion on turbine blades, characterized in that, Includes the following steps: After the turbine is shut down and the accumulated water is drained to create a dry environment, the repair actuator is inserted into the flow channel through the manhole of the volute and moved to the cavitation area on the blade surface. Geometric feature data of the cavitation area were collected, and a thixotropic composite repair material containing magnetic particles was prepared. The composite repair material is injected into the cavitation area according to the geometric feature data, and a controllable magnetic field is applied to drive the magnetic particles to migrate so that the material is compacted and fits the blade profile. The compacted composite repair material is cured until it reaches a preset strength, at which point the repair actuator is removed.

2. The method according to claim 1, characterized in that, After the turbine is shut down and the accumulated water is drained to create a dry environment, the repair actuator is inserted into the flow channel through the manhole of the volute and moved to the cavitation erosion area on the blade surface, including: The multi-degree-of-freedom telescopic robotic arm is fixed at the manhole door of the turbine casing, and the integrated repair head is installed at the end of the multi-degree-of-freedom telescopic robotic arm. The control terminal drives the multi-degree-of-freedom telescopic robotic arm to extend into the turbine flow channel along the inside of the volute, and adjusts the posture of the integrated repair head to reach the surface of the turbine blade. The integrated repair head is moved to the cavitation area on the blade surface to complete the installation and positioning of the repair actuator.

3. The method according to claim 1, characterized in that, The preparation of the thixotropic composite repair material containing magnetic particles includes: Modified epoxy resin or polyurethane resin is selected as the matrix material of component A, and a curing agent that matches the matrix material is selected as component B. Magnetic particles are added to components A and B, wherein the magnetic particles are carbonyl iron powder or ferrite magnetic powder. Wear-resistant aggregates and thixotropic agents are added and mixed to obtain a magnetic polymer composite repair material that is thixotropic paste after mixing.

4. The method according to claim 1, characterized in that, Collect geometric feature data of the cavitation erosion area, including: The contour, depth, and volume of the cavitation erosion area on the blade surface are scanned and measured using the three-dimensional scanning module in the integrated repair head. Obtain the location, depth, and volume information of the cavitation erosion area, and build a three-dimensional model of the cavitation erosion area based on this information; The three-dimensional model is used to calculate the amount of repair material needed, and geometric feature data for controlling the injection amount is obtained.

5. The method according to claim 1, characterized in that, The step of injecting the composite repair material into the cavitation erosion area according to the geometric feature data and applying a controllable magnetic field to drive the magnetic particles to migrate, thereby making the material dense, compacted, and conforming to the blade profile, includes: After the A component and B component are mixed instantly by the mixing and injection module, they are quantitatively injected into the cavitation area according to the geometric feature data, filling it to a level slightly higher than the blade surface. The electromagnetic compaction module in the integrated repair head is activated to generate a local high-intensity magnetic field. The magnetic force is applied to the magnetic particles in the injected composite repair material, guiding the magnetic particles to accumulate towards the blade matrix, thereby achieving densification of the repair material and eliminating internal air bubbles. Based on the fine-tuning of the robotic arm's posture, the flat surface of the repair head is made to fit with the blade profile. The flat surface of the repair head is then used to fit with the blade profile to perform magnetic shaping and repair, resulting in a repair layer that matches the original blade profile.

6. The method according to claim 1, characterized in that, The curing treatment of the compacted composite repair material includes: Activate the auxiliary curing module in the integrated repair head to heat or irradiate the repair area, so that the composite repair material reaches its initial setting strength; Once the composite repair material reaches the preset strength, the curing process is completed and the repair actuator is ready to be withdrawn.

7. The method according to claim 1, characterized in that, After the turbine is shut down and the accumulated water is drained to create a dry environment, the process includes: Close the turbine inlet valve, drain the water from the spiral casing and runner chamber, and open the spiral casing manhole. After a short shutdown and draining the water from the volute and impeller chamber, no manual entry into the flow channel is required; instead, a robotic arm can be used to extend into the flow channel for the operation. Confirm that the volute and impeller chamber meet the requirements for dry environment conditions, satisfying the requirement for in-situ repair without disassembling the impeller.

8. A dry in-situ magnetic control repair device for cavitation of turbine blades, used to implement the method described in any one of claims 1-7, characterized in that, include: A multi-degree-of-freedom telescopic robotic arm is installed at the manhole or inspection port of the turbine casing to extend into the runner flow channel along the inside of the casing. Its end can be adjusted to reach the surface of the turbine blades. An integrated repair head, installed at the end of the multi-degree-of-freedom telescopic robotic arm, integrates a three-dimensional scanning module, a mixing and spraying module, an electromagnetic compaction module, and an auxiliary curing module. It is used to complete the scanning measurement of the cavitation area, the injection of repair material, magnetic field compaction, and curing treatment. A repair material supply system, connected to the integrated repair head, is used to store and transport thixotropic composite repair material containing magnetic particles; The control terminal, located outside the volute, is used for centralized control of the robotic arm's movement, scanning data, material injection volume, electromagnetic field strength, and curing process.

9. A computer device, characterized in that, Including processor and memory; The processor reads executable program code stored in the memory to run a program corresponding to the executable program code, so as to implement the dry in-situ magnetic control repair method for cavitation of turbine blades as described in any one of claims 1-7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements a dry in-situ magnetic control repair method for cavitation of turbine blades as described in any one of claims 1-7.

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