Vibration suppression and stress reduction design method for mixed-flow water turbine runner blade profile

Abstract

The invention belongs to the technical field of water turbines, and particularly discloses a mixed-flow water turbine runner blade profile vibration suppression and stress reduction design method. According to the method, the target vibration suppression and stress reduction strategy is determined according to the stress concentration area and the characteristic information of the mixed-flow water turbine, the blade outlet edge of the mixed-flow water turbine runner is preprocessed according to the target vibration suppression and stress reduction strategy, and the root of the mixed-flow water turbine runner is cut back; and the stress of the stress concentration area is reduced according to the treated blade outlet edge and the back-cut rotating wheel root. Through the mode, the blade outlet edge is swept back and the boundary blade is thickened by using the vibration suppression and stress reduction strategy of the blade outlet edge dimension, and the root is cut back by using the vibration suppression and stress reduction strategy of the rotating wheel root dimension, so that the optimization of the load distribution of the rotating wheel blade is realized, and the high-frequency vibration is suppressed; therefore, the accuracy and efficiency of stress reduction can be effectively improved, and stress concentration is reduced.

Description

Technical Field

[0001] This application belongs to the field of water turbine technology, and more specifically, relates to a method for designing vibration suppression and stress reduction of the runner blade profile of a mixed-flow water turbine. Background Technology

[0002] As the core equipment for hydropower energy conversion, the structural safety of the runner blades in a mixed-flow turbine directly determines the reliability and lifespan of the unit. During operation, the blades are subjected to complex alternating loads such as centrifugal force, water flow impact loads, and temperature stress. Stress concentration is particularly prone to occur at the outlet edge, becoming a weak point for the initiation and propagation of fatigue cracks, which can lead to unit shutdown or even complete damage. Currently, the common method for reducing stress concentration areas is to uniformly modify the entire blade structure, for example, by thickening all blades. However, this modification process relies on experience-based trial and error iteration, resulting in long development cycles and low efficiency. Therefore, the accuracy and efficiency of this stress reduction method are relatively low. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the purpose of this application is to provide a method for designing vibration suppression and stress reduction of the runner blade profile of a mixed-flow turbine, which aims to solve the problem of low accuracy and efficiency in stress reduction of the prior art.

[0004] To achieve the above objectives, in a first aspect, this application provides a method for designing vibration-damping and stress-reducing profiles of mixed-flow turbine runner blades, comprising: To identify the stress concentration areas during the operation of a mixed-flow turbine; The target vibration suppression and stress reduction strategy is determined based on the stress concentration region and the characteristic information of the mixed-flow turbine. The target vibration suppression and stress reduction strategy includes a vibration suppression and stress reduction strategy at the blade outlet edge dimension and a vibration suppression and stress reduction strategy at the runner root dimension. The blade exit edge of the mixed-flow turbine runner is pre-processed according to the vibration suppression and stress reduction strategy of the blade exit edge dimension, and the root of the mixed-flow turbine runner is back-cut according to the vibration suppression and stress reduction strategy of the runner root dimension. The stress in the stress concentration area is reduced by adjusting the treated blade exit edge and the shear root after back-cutting.

[0005] In one embodiment, the step of preprocessing the blade exit edge of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy based on the blade exit edge dimension includes: The position information of the blades of the mixed-flow turbine runner is obtained, and the middle blades and boundary blades of the mixed-flow turbine runner are determined based on the position information of the blades. According to the vibration suppression and stress reduction strategy based on the exit edge dimension of the blade, the exit edge of each of the intermediate blades is swept back. Obtain a near-standard symmetric airfoil and determine the target thickness data based on the near-standard symmetric airfoil; Based on the vibration suppression and stress reduction strategy of the blade exit edge dimension and the target thickness data, the exit edge of each of the boundary blades is thickened respectively.

[0006] In one embodiment, the step of sweeping back the exit edge of each of the intermediate blades according to the vibration suppression and stress reduction strategy based on the exit edge dimension of the blade includes: Obtain the distance between each of the intermediate blades and the boundary blades, and divide each of the intermediate blades into edge intermediate blades and center intermediate blades according to the distance; Obtain a high-load airfoil and determine the edge sweep degree based on the high-load airfoil; The exit edge of each of the middle blades is swept back according to the degree of edge sweeping; Obtain a low-speed, high-lift airfoil and determine the positive sweep degree based on the low-speed, high-lift airfoil, wherein the positive sweep degree is greater than the edge sweep degree; The exit edge of each of the central blades is swept back according to the degree of positive sweep.

[0007] In one embodiment, the step of back-cutting the root of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy based on the root dimension of the runner includes: Obtain the current location information of the stress concentration area during the operation of the mixed-flow turbine; Determine the cutback start position based on the current position information; The backcut shape, backcut region, and backcut depth are determined based on the vibration suppression and stress reduction strategy at the root dimension of the impeller. The root of the mixed-flow turbine runner is back-cut according to the back-cut starting position, the back-cut shape, the back-cut area, and the back-cut depth.

[0008] In one embodiment, the step of reducing the stress in the stress concentration region based on the treated blade exit edge and the sheared impeller root includes: Obtain the thickness at the middle position of the exit edge of the processed blade; The thickness of the leaf root is adjusted according to the thickness at the intermediate position; All blades of the mixed-flow turbine are determined based on the adjusted blade root and the pre-treated blade outlet edge, and the current thickness of all blades is obtained. The current thickness of all blades is transitioned based on a linear transition strategy; The stress in the stress concentration area is reduced based on all the treated blades and the root of the re-cut impeller.

[0009] In one embodiment, the step of reducing the stress in the stress concentration region based on all processed blades and the shear root after backcutting includes: Finite element simulation was performed on all the processed blades and the root of the runner after back-cutting. Calculate the stress in the stress concentration region at the current moment based on the simulation results; Obtain the stress in the stress concentration region at the previous moment; If the stress in the stress concentration region at the current moment is less than the stress at the previous moment, then the stress reduction in the stress concentration region is completed. The step of reducing the stress in the stress concentration area based on all the processed blades and the root of the re-cut impeller further includes: The target vibration suppression and stress reduction strategy is encapsulated, and a vibration suppression and stress reduction script is generated based on the encapsulation result; In response to a stress reduction command on the user interface, a vibration suppression and stress reduction script is triggered according to the stress reduction command. The stress concentration area of ​​other mixed-flow turbines of the same type as mixed-flow turbines is reduced by triggering a vibration damping and stress reduction script.

[0010] Secondly, this application provides a design device for vibration suppression and stress reduction of the blade profile of a mixed-flow turbine runner, comprising: The acquisition module is used to acquire the stress concentration area during the operation of the mixed-flow turbine; The determination module is used to determine the target vibration suppression and stress reduction strategy based on the stress concentration region and the characteristic information of the mixed-flow turbine, wherein the target vibration suppression and stress reduction strategy includes a vibration suppression and stress reduction strategy at the blade outlet edge dimension and a vibration suppression and stress reduction strategy at the runner root dimension. The processing module is used to preprocess the blade outlet edge of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy of the blade outlet edge dimension, and to back-cut the root of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy of the runner root dimension. The stress reduction module is used to reduce the stress in the stress concentration area based on the processed blade exit edge and the shear root after backcutting.

[0011] Thirdly, this application provides an electronic device, comprising: at least one memory for storing a program; and at least one processor for executing the program stored in the memory, wherein when the program stored in the memory is executed, the processor is configured to execute the method described in the first aspect or any possible implementation thereof.

[0012] Fourthly, this application provides a computer-readable storage medium storing a computer program that, when run on a processor, causes the processor to perform the method described in the first aspect or any possible implementation thereof.

[0013] Fifthly, this application provides a computer program product that, when run on a processor, causes the processor to perform the method described in the first aspect or any possible implementation thereof.

[0014] It is understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0015] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: (1) This application employs different sweeping degrees for different blades, which is targeted. Furthermore, it thickens the exit edge of each boundary blade according to the vibration suppression and stress reduction strategy based on the blade exit edge dimension, rather than thickening all blades. This reduces the intensity of the trailing edge vortex, suppresses the Karman vortex, and ensures the stability of the runner exit wake and the flow stability in the tailrace pipe. Then, combined with the vibration suppression and stress reduction strategy based on the runner root dimension, the root of the mixed-flow turbine runner is back-cut. At this time, the blade profile of the entire mixed-flow turbine is redesigned. By optimizing the load distribution of the runner blades, the stress in the stress concentration area is reduced, which can suppress the crack at the exit edge, reduce the stress concentration at the root, achieve root strengthening and stress gradient control, effectively suppress high-frequency vibration, and improve the accuracy and efficiency of stress reduction.

[0016] (2) In order to effectively improve the efficiency of reducing stress in the stress concentration area of ​​other mixed-flow turbines, after reducing the stress in the stress concentration area of ​​the mixed-flow turbine during operation, this application still adopts the strategy encapsulation method to encapsulate the target vibration suppression and stress reduction strategy into a vibration suppression and stress reduction script. Then, the trigger script is used to directly thicken, sweep back, and cut back the root of the blade outlet edge of other mixed-flow turbines to reduce the stress in the stress concentration area. At this time, it is not necessary to obtain the stress concentration area and redetermine the vibration suppression and stress reduction strategy, thereby effectively improving the efficiency of stress reduction.

[0017] In summary, this application obtains the stress concentration region during the operation of a mixed-flow turbine; determines a target vibration suppression and stress reduction strategy based on the stress concentration region and the characteristic information of the mixed-flow turbine, wherein the target vibration suppression and stress reduction strategy includes a vibration suppression and stress reduction strategy at the blade exit edge dimension and a vibration suppression and stress reduction strategy at the runner root dimension; preprocesses the blade exit edge of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy at the blade exit edge dimension, and performs back-cutting on the root of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy at the runner root dimension; and reduces the stress in the stress concentration region based on the processed blade exit edge and the back-cut runner root. Through the above method, by using the vibration suppression and stress reduction strategy at the blade exit edge dimension to sweep back the blade exit edge and thicken the boundary blades, and by using the vibration suppression and stress reduction strategy at the runner root dimension to back-cut the root, the load distribution of the runner blades is optimized, effectively suppressing high-frequency vibration, thereby effectively improving the accuracy and efficiency of stress reduction and reducing stress concentration. Attached Figure Description

[0018] Figure 1 This is one of the flowcharts illustrating the vibration suppression and stress reduction design method for the runner blade profile of a mixed-flow turbine provided in this application embodiment; Figure 2 This is a schematic diagram showing the position of the blades of the mixed-flow turbine runner provided in an embodiment of this application; Figure 3 This is a schematic diagram showing the location of the root of the mixed-flow turbine runner provided in an embodiment of this application; Figure 4 This is the second flowchart illustrating the design method for vibration suppression and stress reduction of the runner blade profile of a mixed-flow turbine provided in this application embodiment; Figure 5 This is a schematic diagram of the module structure of the mixed-flow turbine runner blade profile vibration suppression and stress reduction design device provided in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] In this article, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The symbol " / " in this article indicates that the related objects are in an "or" relationship; for example, A / B means A or B.

[0021] The terms "first" and "second," etc., used in the specification and claims herein are used to distinguish different objects, not to describe a specific order of objects. For example, "first response message" and "second response message," etc., are used to distinguish different response messages, not to describe a specific order of response messages.

[0022] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0023] Based on this, embodiments of this application provide a method for designing vibration suppression and stress reduction of the turbine runner blade profile, referring to... Figure 1 , Figure 1 This is one of the flowcharts illustrating the vibration suppression and stress reduction design method for the runner blade profile of a mixed-flow turbine provided in this application. In this embodiment, the vibration suppression and stress reduction design method for the runner blade profile of a mixed-flow turbine includes steps S10 to S40: Step S10: Obtain the stress concentration area during the operation of the mixed-flow turbine.

[0024] It should be noted that the stress concentration area refers to the region where stress accumulates during the operation of a mixed-flow turbine. This stress concentration area can be the blade outlet edge, near the root of the upper crown and lower ring. If the stress in this stress concentration area is not reduced in a timely and accurate manner, it can lead to serious consequences such as fatigue cracks and structural failure. Therefore, this embodiment presents a targeted vibration suppression and stress reduction strategy, which transfers the pressure load on the blade surface from the root to the middle and outer edge, reducing the pressure load on the blade outlet edge, optimizing the load distribution of the runner blades, effectively suppressing high-frequency vibration, thereby effectively improving the accuracy and efficiency of stress reduction and reducing stress concentration.

[0025] It should be understood that mixed-flow turbines belong to the reaction turbine category. Their core characteristic is that water flows radially into the runner and then flows out axially within the runner. Energy conversion is achieved through the interaction between the runner blades and the water flow. For example, the potential and kinetic energy of the water flow is converted into the mechanical energy of the runner, which then drives the generator to generate electricity.

[0026] Step S20: Determine the target vibration suppression and stress reduction strategy based on the stress concentration region and the characteristic information of the mixed-flow turbine. The target vibration suppression and stress reduction strategy includes a vibration suppression and stress reduction strategy at the blade outlet edge dimension and a vibration suppression and stress reduction strategy at the runner root dimension.

[0027] It is understandable that the target vibration suppression and stress reduction strategy refers to a strategy that reduces stress in stress concentration areas by suppressing high-frequency vibrations. This target vibration suppression and stress reduction strategy can be determined comprehensively based on the stress concentration area and the characteristic information of the mixed-flow turbine. For mixed-flow turbines with different characteristic information or different stress concentration areas, the determined target vibration suppression and stress reduction strategy will also be different. In this embodiment, the target vibration suppression and stress reduction strategy includes a vibration suppression and stress reduction strategy at the blade outlet edge dimension and a vibration suppression and stress reduction strategy at the runner root dimension. The vibration suppression and stress reduction strategy at the blade outlet edge dimension is used to thicken and sweep back the blade outlet edge of the mixed-flow turbine runner, while the vibration suppression and stress reduction strategy at the runner root dimension is used to cut back the root of the mixed-flow turbine runner.

[0028] Step S30: Preprocess the blade outlet edge of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy of the blade outlet edge dimension, and back-cut the root of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy of the runner root dimension.

[0029] It should be understood that since the root stress is affected by the resultant load of the entire blade, the blade exit edge of the mixed-flow turbine runner can be swept back according to the vibration suppression and stress reduction strategy based on the blade exit edge dimension. This reduces the stress distribution at the root of the exit edge and avoids stress concentration at the exit edge root. Simultaneously, the blade exit edge of the mixed-flow turbine runner can be thickened according to the vibration suppression and stress reduction strategy based on the blade exit edge dimension. Furthermore, the root of the mixed-flow turbine runner can be cut back according to the vibration suppression and stress reduction strategy based on the runner root dimension to achieve a rounded corner or curved surface transition, reducing stress concentration.

[0030] Further, the step of preprocessing the blade exit edge of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy based on the blade exit edge dimension includes: obtaining the position information of the blades of the mixed-flow turbine runner, and determining the intermediate blades and boundary blades of the mixed-flow turbine runner according to the blade position information; sweeping back the exit edge of each of the intermediate blades according to the vibration suppression and stress reduction strategy based on the blade exit edge dimension; obtaining a near-standard symmetric airfoil, and determining the target thickness data according to the near-standard symmetric airfoil; and thickening the exit edge of each of the boundary blades according to the vibration suppression and stress reduction strategy based on the blade exit edge dimension and the target thickness data.

[0031] Understandably, reference Figure 2 , Figure 2This diagram illustrates the blade positions of a mixed-flow turbine runner, using seven blades as an example: Span01, Span02, Span03, Span04, Span05, Span06, and Span07. Based on these positions, the intermediate and boundary blades of the mixed-flow turbine runner can be determined. For instance, the intermediate blades can be Span02, Span03, Span04, Span05, and Span06, while the boundary blades can be Span01 and Span07. To avoid the low-pressure area on the blade back coinciding with the cavitation zone and to reduce cavitation-induced excitation, the exit edges of each intermediate blade can be swept back according to a vibration suppression and stress reduction strategy based on the blade exit edge dimension. The sweep angle corresponding to the sweep degree can be 10-20°, and the initial sweep position is 50%~70% of the blade chord length. This sweep can be axial sweep, and the specific sweep formula can be expressed as:

[0032] in, Indicates the axial coordinates after sweeping. Indicates the sweep angle. The radial coordinate (independent variable) represents any position of the blade. Indicates the radial coordinates of the sweep start point. Indicates the axial reference point.

[0033] It should be noted that the quasi-standard symmetric airfoil refers to an airfoil derived from the classic standard symmetric airfoil after adjustments. The classic standard symmetric airfoil can be NACA 63-012. After determining the target thickness data based on the quasi-standard symmetric airfoil, the exit edge of each boundary blade can be thickened from the inlet to the outlet direction according to the vibration suppression and stress reduction strategy of the blade exit edge dimension and the target thickness data. This improves local strength and fatigue life, increases the cross-sectional area of ​​the transition zone, reduces the stress concentration factor, and delays the initiation of fatigue cracks.

[0034] Further, the step of sweeping the exit edge of each of the intermediate blades according to the vibration suppression and stress reduction strategy based on the exit edge dimension includes: obtaining the distance between each of the intermediate blades and the boundary blades, and dividing each of the intermediate blades into edge-intermediate blades and center-intermediate blades according to the distance; obtaining a high-load airfoil-like configuration, and determining the degree of edge sweep according to the high-load airfoil-like configuration; sweeping the exit edge of each of the edge-intermediate blades according to the degree of edge sweep; obtaining a low-speed high-lift airfoil-like configuration, and determining the degree of positive sweep according to the low-speed high-lift airfoil-like configuration, wherein the degree of positive sweep is greater than the degree of edge sweep; and sweeping the exit edge of each of the center-intermediate blades according to the degree of positive sweep.

[0035] It should be understood that due to the differences in spanwise airflow characteristics and load distribution among different blades, different degrees of sweep are required for the edge-middle blades and the center blades, respectively. Before this, each blade needs to be divided into edge-middle blades and center blades based on distance, referring to... Figure 2 It can be seen that the edge middle blades can be Span02 and Span06, and the center blades can be Span03, Span04, and Span05.

[0036] It should be noted that "high-load-like airfoil" refers to an airfoil derived from a special high-load airfoil, such as the K3311. Similarly, "low-speed high-lift-like airfoil" refers to an airfoil derived from a classic low-speed high-lift airfoil, such as the WORTMANN FX 63-137. After determining the trailing edge sweep degree based on the high-load-like airfoil and the positive sweep degree based on the low-speed high-lift-like airfoil, the exit edges of the middle blades on each side can be swept back according to the trailing edge sweep degree, and the exit edges of the middle blades can be swept back according to the positive sweep degree. This modifies the trailing edge shape and reduces the periodic load caused by wake shedding. Furthermore, the positive sweep degree is greater than the trailing edge sweep degree; that is, the sweep of the exit edge of the middle blade can be called a slight sweep, and the sweep of the exit edge of the middle blade can be called a large sweep.

[0037] It is understandable that by thickening and sweeping the exit edge of the blade, the hydraulic profile can be optimized, the pressure gradient in the blade exit acceleration zone can be reduced, and the pressure change in the water flow in the exit acceleration zone can be smoother, avoiding flow separation, eddy current loss, and cavitation risks caused by excessive pressure gradient. In order to effectively improve the local cavitation margin, this embodiment will also optimize the cavitation-prone area on the back of the blade. Essentially, this is a combination of "active cavitation suppression" and "passive damage mitigation". By optimizing the blade geometry, the minimum pressure on the blade surface is increased, approaching the mainstream pressure. Furthermore, anti-cavitation blade geometry (such as edge chamfering and curved sweepback) design will be considered to slow down the growth of cavitation-induced cracks. The purpose of considering edge chamfering is to suppress cavitation generation, and the purpose of considering curved sweepback is to disperse the low-pressure area.

[0038] Furthermore, the step of back-cutting the root of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy at the runner root dimension includes: obtaining the current position information of the stress concentration area during the operation of the mixed-flow turbine; determining the back-cutting start position based on the current position information; determining the back-cutting shape, back-cutting area, and back-cutting depth according to the vibration suppression and stress reduction strategy at the runner root dimension; and back-cutting the root of the mixed-flow turbine runner according to the back-cutting start position, the back-cutting shape, the back-cutting area, and the back-cutting depth.

[0039] Understandably, in order to achieve rounded corners or curved surface transitions and reduce stress concentration, the root of the mixed-flow turbine runner will be back-cut. The back-cut parameters include, but are not limited to, the back-cut starting position, back-cut shape, back-cut area, and back-cut depth. The back-cut starting position can be determined based on the current location information of the stress concentration area during the operation of the mixed-flow turbine. For example, if the current location information of the stress concentration area is the root near the upper crown and lower ring, then the root is taken as the back-cut starting position, that is, the back-cut is still performed from this root. The back-cut shape can be an arc, the back-cut area can be the area formed along the direction of the blade exit edge from the root to a position of 3-5 times the chord length, and the back-cut depth can be the vertical depth of the arc's chord length.

[0040] It should be noted that the reference Figure 3 , Figure 3 This is a schematic diagram of the root position of the runner of a mixed-flow turbine. Specifically, taking seven blades as an example, namely blades Span01, Span02, Span03, Span04, Span05, Span06, and Span07, the roots of the backcut are the roots of Span01 and Span07, respectively. The backcut is performed on the roots of Span01 and Span07 according to the backcut starting position, backcut shape, backcut area, and backcut depth to achieve rounded corners or curved surface transitions.

[0041] Step S40: Reduce the stress in the stress concentration area based on the treated blade exit edge and the cut-back impeller root.

[0042] Understandably, after the aforementioned thickening, sweeping, and back-cutting processes, the blade profile of the entire mixed-flow turbine was redesigned. By optimizing the load distribution of the runner blades, the stress in the stress concentration area was reduced, which can suppress cracks at the outlet edge, reduce stress concentration at the root, and achieve root strengthening and stress gradient control.

[0043] This embodiment obtains the stress concentration region during the operation of a mixed-flow turbine; based on the stress concentration region and the characteristic information of the mixed-flow turbine, a target vibration suppression and stress reduction strategy is determined. This target strategy includes a vibration suppression and stress reduction strategy at the blade exit edge and a vibration suppression and stress reduction strategy at the runner root. The blade exit edge of the mixed-flow turbine runner is pre-processed according to the blade exit edge vibration suppression and stress reduction strategy, and the root of the mixed-flow turbine runner is back-cut according to the runner root vibration suppression and stress reduction strategy. The stress in the stress concentration region is reduced based on the processed blade exit edge and the back-cut runner root. Through the above method, by using the blade exit edge vibration suppression and stress reduction strategy to sweep back the blade exit edge and thicken the boundary blades, and by using the runner root vibration suppression and stress reduction strategy to back-cut the root, the load distribution of the runner blades is optimized, effectively suppressing high-frequency vibration, thereby effectively improving the accuracy and efficiency of stress reduction and reducing stress concentration.

[0044] In one specific embodiment, this application provides steps for reducing stress in stress concentration regions. Please refer to... Figure 4 , Figure 4 This is the second flowchart illustrating the vibration suppression and stress reduction design method for the runner blade profile of a mixed-flow turbine provided in this application. Step S40 includes steps S401 to S405: Step S401: Obtain the thickness at the middle position of the processed blade exit edge.

[0045] Step S402: Adjust the thickness of the leaf root according to the thickness at the intermediate position.

[0046] It is understandable that the thickness at the middle position refers to the thickness at the very center of the blade's exit edge after treatment. In order to further reduce the intensity of the trailing edge vortex and suppress the Karman vortex, it is also necessary to adjust the thickness of the blade root according to the thickness at the middle position. For example, the thickness of the blade root after adjustment is 1.5 to 2 times the thickness at the middle position of the blade's exit edge.

[0047] Step S403: Determine all blades of the mixed-flow turbine based on the adjusted blade root and the pre-treated blade outlet edge, and obtain the current thickness of all blades.

[0048] Step S404: Perform transition processing on the current thickness of all blades based on a linear transition strategy.

[0049] It is understandable that the linear transition strategy refers to using a linear transition method to transition the thickness of multiple blades, so that the thickness of all blades changes linearly, controlling the strength of the blades to gradually transition, achieving the design goal of equal strength, and thus helping to control the root stress to gradually transition radially.

[0050] Step S405: Reduce the stress in the stress concentration area based on all the processed blades and the root of the recut impeller.

[0051] It should be understood that after the current thickness of all blades is transitioned, the blade profile of the entire mixed-flow turbine is redesigned in conjunction with the cut-back runner root. By optimizing the load distribution of the runner blades, the stress in the stress concentration area is reduced.

[0052] Further, the step of reducing the stress in the stress concentration region based on all processed blades and the cut-back runner root includes: performing finite element simulation on all processed blades and the cut-back runner root; calculating the stress in the stress concentration region at the current moment based on the simulation results; obtaining the stress in the stress concentration region at the previous moment; if the stress in the stress concentration region at the current moment is less than the stress at the previous moment, then the stress reduction in the stress concentration region is completed; wherein, after the step of reducing the stress in the stress concentration region based on all processed blades and the cut-back runner root, the method further includes: encapsulating the target vibration suppression and stress reduction strategy, and generating a vibration suppression and stress reduction script based on the encapsulation result; responding to a stress reduction command on the operation interface, triggering the vibration suppression and stress reduction script based on the stress reduction command; reducing the stress in the stress concentration region of other mixed-flow turbines of the same type as the mixed-flow turbine through the triggered vibration suppression and stress reduction script.

[0053] It should be noted that, in order to verify that the stress in this embodiment can be reduced by designing the blade profile of the mixed-flow turbine runner, after redesigning the blade profile of the entire mixed-flow turbine, finite element simulations are performed on all the processed blades and the runner root after back-cutting. Based on the simulation results, the stress in the stress concentration area at the current moment is calculated, and then it is determined whether the stress in the stress concentration area at the current moment is less than the stress at the previous moment. If so, it indicates that the stress in the stress concentration area has been reduced.

[0054] Understandably, in order to effectively improve the efficiency of reducing stress in the stress concentration areas of other mixed-flow turbines, after determining that the target vibration suppression and stress reduction strategy can effectively reduce stress, the target vibration suppression and stress reduction strategy can be encapsulated into a vibration suppression and stress reduction script. After detecting the stress reduction command from the operation interface, the vibration suppression and stress reduction script can be triggered to directly thicken, sweep back, and cut back the root of the blades of other mixed-flow turbines, thereby reducing the stress in the stress concentration areas. At this time, it is not necessary to obtain the stress concentration areas and redetermine the vibration suppression and stress reduction strategy, thus achieving the effect of effectively improving the efficiency of stress reduction.

[0055] This embodiment obtains the thickness at the midpoint of the processed blade exit edge; adjusts the thickness of the blade root based on the midpoint thickness; determines all blades of the mixed-flow turbine based on the adjusted blade root and the pre-processed blade exit edge, and obtains the current thickness of all blades; performs transition processing on the current thickness of all blades based on a linear transition strategy; and reduces the stress in the stress concentration area based on the processed blades and the recut runner root. Through the above method, after thickening and sweeping the blade exit edge of the mixed-flow turbine runner, the current thickness of all blades is further transitioned based on a linear transition strategy, resulting in a linear transition in the thickness of all blades. This controls the gradual transition of blade strength, achieving the equal strength design goal. Then, combined with the recut runner root, the blade profile of the entire mixed-flow turbine is redesigned. By optimizing the load distribution of the runner blades, the stress in the stress concentration area is reduced, thereby effectively improving the accuracy and efficiency of stress reduction.

[0056] The following describes the vibration suppression and stress reduction design device for the mixed-flow turbine runner blade profile provided in this application. The vibration suppression and stress reduction design device for the mixed-flow turbine runner blade profile described below can be referred to in conjunction with the vibration suppression and stress reduction design method for the mixed-flow turbine runner blade profile described above. Please refer to... Figure 5 , Figure 5 This is a schematic diagram of the module structure of the mixed-flow turbine runner blade profile vibration suppression and stress reduction design device provided in this application embodiment, including: The acquisition module T10 is used to acquire the stress concentration area during the operation of the mixed-flow turbine.

[0057] The determination module T20 is used to determine the target vibration suppression and stress reduction strategy based on the stress concentration region and the characteristic information of the mixed-flow turbine. The target vibration suppression and stress reduction strategy includes a vibration suppression and stress reduction strategy at the blade outlet edge dimension and a vibration suppression and stress reduction strategy at the runner root dimension.

[0058] The processing module T30 is used to preprocess the blade outlet edge of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy of the blade outlet edge dimension, and to back-cut the root of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy of the runner root dimension.

[0059] The stress reduction module T40 is used to reduce the stress in the stress concentration area based on the processed blade exit edge and the shear root after backcutting.

[0060] This embodiment obtains the stress concentration region during the operation of a mixed-flow turbine; based on the stress concentration region and the characteristic information of the mixed-flow turbine, a target vibration suppression and stress reduction strategy is determined. This target strategy includes a vibration suppression and stress reduction strategy at the blade exit edge and a vibration suppression and stress reduction strategy at the runner root. The blade exit edge of the mixed-flow turbine runner is pre-processed according to the blade exit edge vibration suppression and stress reduction strategy, and the root of the mixed-flow turbine runner is back-cut according to the runner root vibration suppression and stress reduction strategy. The stress in the stress concentration region is reduced based on the processed blade exit edge and the back-cut runner root. Through the above method, by using the blade exit edge vibration suppression and stress reduction strategy to sweep back the blade exit edge and thicken the boundary blades, and by using the runner root vibration suppression and stress reduction strategy to back-cut the root, the load distribution of the runner blades is optimized, effectively suppressing high-frequency vibration, thereby effectively improving the accuracy and efficiency of stress reduction and reducing stress concentration.

[0061] It is understood that the detailed functional implementation of each of the above modules can be found in the description of the aforementioned method embodiments, and will not be repeated here.

[0062] It should be understood that the above-described device is used to execute the methods in the above embodiments. The implementation principle and technical effect of the corresponding program modules in the device are similar to those described in the above methods. The working process of the device can be referred to the corresponding process in the above methods, and will not be repeated here.

[0063] Based on the methods in the above embodiments, this application provides an electronic device, please refer to... Figure 6 , Figure 6 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application.

[0064] It should be noted that the system may include: a processor 10, a communication interface 20, a memory 30, and a communication bus 40. The processor 10, communication interface 20, and memory 30 communicate with each other via the communication bus 40. The processor 10 can call logical instructions stored in the memory 30 to execute the methods described in the above embodiments.

[0065] Furthermore, the logical instructions in the aforementioned memory 30 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0066] Based on the methods in the above embodiments, this application provides a computer-readable storage medium storing a computer program that, when run on a processor, causes the processor to execute the methods in the above embodiments.

[0067] Based on the methods in the above embodiments, this application provides a computer program product that, when run on a processor, causes the processor to execute the methods in the above embodiments.

[0068] It is understood that the processor in the embodiments of this application can be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, field-programmable gate arrays, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0069] The method steps in this application embodiment can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor.

[0070] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. Those skilled in the art will readily understand that the above descriptions are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for designing vibration suppression and stress reduction of the turbine runner blade profile in a mixed-flow turbine, characterized in that, include: To identify the stress concentration areas during the operation of a mixed-flow turbine; The target vibration suppression and stress reduction strategy is determined based on the stress concentration region and the characteristic information of the mixed-flow turbine. The target vibration suppression and stress reduction strategy includes a vibration suppression and stress reduction strategy at the blade outlet edge dimension and a vibration suppression and stress reduction strategy at the runner root dimension. The blade exit edge of the mixed-flow turbine runner is pre-processed according to the vibration suppression and stress reduction strategy of the blade exit edge dimension, and the root of the mixed-flow turbine runner is back-cut according to the vibration suppression and stress reduction strategy of the runner root dimension. The stress in the stress concentration area is reduced by adjusting the treated blade exit edge and the shear root after back-cutting.

2. The method as described in claim 1, characterized in that, The step of pre-processing the blade exit edge of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy based on the blade exit edge dimension includes: The position information of the blades of the mixed-flow turbine runner is obtained, and the middle blades and boundary blades of the mixed-flow turbine runner are determined based on the position information of the blades. According to the vibration suppression and stress reduction strategy based on the exit edge dimension of the blade, the exit edge of each of the intermediate blades is swept back. Obtain a near-standard symmetric airfoil and determine the target thickness data based on the near-standard symmetric airfoil; Based on the vibration suppression and stress reduction strategy of the blade exit edge dimension and the target thickness data, the exit edge of each of the boundary blades is thickened respectively.

3. The method as described in claim 2, characterized in that, The step of sweeping back the exit edge of each of the intermediate blades according to the vibration suppression and stress reduction strategy based on the exit edge dimension includes: Obtain the distance between each of the intermediate blades and the boundary blades, and divide each of the intermediate blades into edge intermediate blades and center intermediate blades according to the distance; Obtain a high-load airfoil and determine the edge sweep degree based on the high-load airfoil; The exit edge of each of the middle blades is swept back according to the degree of edge sweeping; Obtain a low-speed, high-lift airfoil and determine the positive sweep degree based on the low-speed, high-lift airfoil, wherein the positive sweep degree is greater than the edge sweep degree; The exit edge of each of the central blades is swept back according to the degree of positive sweep.

4. The method as described in claim 1, characterized in that, The step of back-cutting the root of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy based on the root dimension of the runner includes: Obtain the current location information of the stress concentration area during the operation of the mixed-flow turbine; Determine the cutback start position based on the current position information; The backcut shape, backcut region, and backcut depth are determined based on the vibration suppression and stress reduction strategy at the root dimension of the impeller. The root of the mixed-flow turbine runner is back-cut according to the back-cut starting position, the back-cut shape, the back-cut area, and the back-cut depth.

5. The method according to any one of claims 1 to 4, characterized in that, The step of reducing the stress in the stress concentration area based on the treated blade exit edge and the sheared impeller root includes: Obtain the thickness at the middle position of the exit edge of the processed blade; The thickness of the leaf root is adjusted according to the thickness at the intermediate position; All blades of the mixed-flow turbine are determined based on the adjusted blade root and the pre-treated blade outlet edge, and the current thickness of all blades is obtained. The current thickness of all blades is transitioned based on a linear transition strategy; The stress in the stress concentration area is reduced based on all the treated blades and the root of the re-cut impeller.

6. The method as described in claim 5, characterized in that, The step of reducing the stress in the stress concentration area based on all treated blades and the root of the re-cut impeller includes: Finite element simulation was performed on all the processed blades and the root of the runner after back-cutting. Calculate the stress in the stress concentration region at the current moment based on the simulation results; Obtain the stress in the stress concentration region at the previous moment; If the stress in the stress concentration region at the current moment is less than the stress at the previous moment, then the stress reduction in the stress concentration region is completed. The step of reducing the stress in the stress concentration area based on all the processed blades and the root of the re-cut impeller further includes: The target vibration suppression and stress reduction strategy is encapsulated, and a vibration suppression and stress reduction script is generated based on the encapsulation result; In response to a stress reduction command on the user interface, a vibration suppression and stress reduction script is triggered according to the stress reduction command. The stress concentration area of ​​other mixed-flow turbines of the same type as mixed-flow turbines is reduced by triggering a vibration damping and stress reduction script.

7. A vibration suppression and stress reduction design device for the blade profile of a mixed-flow turbine runner, characterized in that, include: The acquisition module is used to acquire the stress concentration area during the operation of the mixed-flow turbine; The determination module is used to determine the target vibration suppression and stress reduction strategy based on the stress concentration region and the characteristic information of the mixed-flow turbine, wherein the target vibration suppression and stress reduction strategy includes a vibration suppression and stress reduction strategy at the blade outlet edge dimension and a vibration suppression and stress reduction strategy at the runner root dimension. The processing module is used to preprocess the blade outlet edge of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy of the blade outlet edge dimension, and to back-cut the root of the mixed-flow turbine runner according to the vibration suppression and stress reduction strategy of the runner root dimension. The stress reduction module is used to reduce the stress in the stress concentration area based on the processed blade exit edge and the shear root after backcutting.

8. An electronic device, characterized in that, include: At least one memory for storing computer programs; At least one processor is configured to execute a program stored in the memory, wherein when the program stored in the memory is executed, the processor is configured to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is run on the processor, it causes the processor to perform the method as described in any one of claims 1-6.

10. A computer program product, characterized in that, When the computer program product is run on a processor, the processor causes the processor to perform the method as described in any one of claims 1-6.

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