Water turbine component crack operation and maintenance method

Abstract

The invention provides a water turbine part crack operation and maintenance method, and belongs to the technical field of water turbine crack maintenance. The method comprises the following steps: acquiring operation parameters, crack characteristics and far-field stress of a water turbine component, and determining a weight distribution coefficient, a stress intensity factor and the like through stress analysis. According to the method, to-be-evaluated components with weight distribution coefficients, stress intensity factors and the like meeting specific conditions are screened out, processing measures and cost-benefit net present values of the to-be-evaluated components are obtained, risk grade scores of all the measures are determined, a target processing measure with the minimum risk grade score and the cost-benefit net present value exceeding a threshold value is selected, and finally the target processing measure is issued to a user terminal. And a user can maintain the components conveniently. According to the method, the condition of the water turbine component is accurately evaluated by obtaining related parameters and analyzing the bearing force, a scientific basis is provided for decision making, key components are screened according to various parameter standards, the operation and maintenance efficiency is improved, in addition, target processing measures can be determined by comprehensively considering risks and cost benefits, and excessive or insufficient processing is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of water turbine crack maintenance, and in particular to a water turbine component crack maintenance method. Background Art

[0002] The metal parts of the turbine are the key to the stable and efficient operation of the power generation system. During long-term operation, they are prone to damage such as cracks due to mechanical stress and hydraulic erosion. Cracks seriously affect the integrity of the components and increase safety risks. Once discovered, they need to be evaluated and handled in a timely manner. However, in the actual operation of the unit, the timeliness of crack treatment is restricted by many factors, such as unplanned maintenance periods, peak electricity demand, economic benefits, and the need for water level regulation during flood seasons.

[0003] At present, traditional detection methods such as ultrasonic testing, magnetic particle testing, penetration testing and radiographic testing can effectively detect cracks on the surface and inside of components. At the same time, with the advancement of technology, some advanced real-time monitoring technologies are gradually being applied to the operation of turbines, such as integrated real-time monitoring systems, which can monitor cracks in real time without stopping the equipment. In terms of crack treatment, the common practice is to formulate corresponding treatment measures based on experience and rough assessments, such as repairing cracks and replacing damaged parts.

[0004] However, traditional detection methods have the following problems: (1) Since the equipment needs to be shut down, it will affect the power generation of the hydropower station and cause economic losses; (2) Although real-time monitoring technology can monitor during operation, it cannot accurately analyze the combined influence of operating parameters, crack characteristic parameters and far-field stress on complex turbine components; (3) The existing treatment measures lack systematic accuracy and do not fully consider factors such as component weight, stress intensity factor, expansion rate, failure probability, etc. The treatment method is single, and it is difficult to formulate the best and most cost-effective strategy, which is prone to problems of over- or under-treatment. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a method for operating and maintaining cracks in turbine components to solve the above-mentioned problems.

[0006] In order to achieve the above-mentioned object, an embodiment of the present invention provides a method for operating and maintaining cracks in a hydraulic turbine component, comprising: Obtaining operating parameters of multiple components of the turbine, characteristic parameters of cracks and far-field stress of cracks; Based on the operating parameters of each component, the characteristic parameters of the crack and the far-field stress of the crack, the stress analysis of each component is carried out to determine the weight distribution coefficient of each component, the stress intensity factor of the crack, the crack propagation rate and the failure probability; Determine that a component whose weight distribution coefficient is greater than a preset weight distribution coefficient, whose stress intensity factor is greater than a preset stress intensity factor, whose expansion rate is greater than a first preset expansion rate and less than a second preset expansion rate, and whose failure probability is greater than a preset failure probability is a component to be evaluated; Obtain multiple treatment measures and cost-effectiveness net present values ​​of the multiple treatment measures for the component to be evaluated; Determine the risk level score of each treatment measure for each component to be evaluated, and determine the minimum risk level score of each component to be evaluated, and the treatment measure with a cost-effectiveness net present value greater than a preset threshold is the target treatment measure for each component to be evaluated; The target processing measures of each component to be evaluated are sent to the user's terminal device, so that the user can maintain each component to be evaluated according to the target processing measures of each component to be evaluated.

[0007] Optionally, the operating parameters include: multiple evaluation indicators, life expectancy and average lifespan; Different crack shapes have different characteristic parameters of cracks, including: If the crack shape is a circular crack, the characteristic parameters of the crack include the area of ​​the crack; If the crack shape is an elliptical crack, the characteristic parameters of the crack include the major axis radius and the minor axis radius of the crack; If the crack shape is a through crack, the characteristic parameters of the crack include the width and depth of the crack; If the shape of the crack is an edge crack, the characteristic parameters of the crack include the pit depth and pit width of the crack.

[0008] Optionally, based on the operating parameters of each component, the characteristic parameters of the crack and the far-field stress of the crack, a stress analysis is performed on each component to determine the weight distribution coefficient of each component, the stress intensity factor of the crack, the crack propagation rate and the failure probability, including: Based on multiple evaluation indicators of each component, a weight distribution coefficient of each component is obtained; Based on the characteristic parameters of the cracks of each component, the equivalent crack size and geometric correction factor of each component are obtained; Based on the equivalent crack size of each component, the characteristic parameters of the crack, the far-field stress of the crack and the geometric correction factor of the crack, the stress intensity factor of the crack of each component is obtained; Based on the preset maximum far-field stress of each component and the preset minimum far-field stress of the crack, as well as the equivalent crack size of each component, the characteristic parameters of the crack and the geometric correction factor, the maximum stress intensity factor of the crack of each component and the minimum stress intensity factor of the crack of each component are obtained; Based on the maximum stress intensity factor, the minimum stress intensity factor, the first preset material constant and the second preset material constant of the crack of each component, the crack propagation rate of each component is obtained; Based on the expected life and average life of each component, the failure probability of each component is obtained.

[0009] Optionally, based on multiple evaluation indicators of each component, a weight distribution coefficient of each component is obtained, including: The maximum value of each evaluation index, the minimum value of each evaluation index and each evaluation index of each component are normalized using the following formula to obtain each evaluation index of each component after normalization; The following formula is used to calculate the evaluation index of each component after normalization to obtain the weight of each evaluation index of each component; ;in, represents the jth evaluation index of the i-th component, Indicates the number of parts, represents the jth evaluation index of the i-th component after normalization; The following formula is used to calculate the weight of each evaluation index of each component to obtain the information entropy of each evaluation index; ;in, represents the information entropy of the jth evaluation index; The information entropy of each evaluation index is calculated using the following formula to obtain the effective information amount of each evaluation index; ;in, Indicates the effective information amount of each evaluation index; Use the following formula to calculate the effective information volume of each evaluation index and obtain the weight distribution coefficient of each component; ;in, represents the weight distribution coefficient of the i-th component, and n represents the number of evaluation indicators.

[0010] Optionally, the equivalent crack size includes: the radius of an equivalent circular crack, the radius of an equivalent elliptical crack, the depth of an equivalent penetrating crack, and the depth of an equivalent plane crack; The geometric correction factors include: circular crack geometric correction factor, elliptical crack geometric correction factor, penetrating crack geometric correction factor and plane crack geometric correction factor; Based on the characteristic parameters of the cracks of each component, the equivalent crack size and geometric correction factor of each component are obtained, including: For each component: If the shape of the crack is a circular crack, the area of ​​the crack of the component is calculated using the following formula to obtain the radius of the equivalent circular crack of the component, and the preset constant is used as the circular crack geometry correction factor; ;in, represents the radius of the equivalent circular crack of the component, represents the circular crack geometry correction factor, Indicates the area of ​​the crack in the component, represents pi; If the shape of the crack is an elliptical crack, the major axis radius and the minor axis radius of the crack of the component are calculated using the following formula to obtain the radius of the equivalent elliptical crack of the component and the elliptical crack geometric correction factor; ;in, represents the radius of the equivalent elliptical crack of the component, represents the geometric correction factor for elliptical cracks, represents the major axis radius of the crack in the component, The minor axis radius of the crack representing the component; If the crack shape is a penetrating crack, the width and depth of the crack of the component are calculated using the following formula to obtain the depth of the equivalent penetrating crack of the component; ;in, Indicates the depth of the equivalent through-crack of the component, represents the geometric correction factor of penetrating cracks, Indicates the depth of the crack in the component, Indicates the width of the crack in the component; If the shape of the crack is an edge crack, the pit depth and pit width of the crack of the component are calculated using the following formula to obtain the depth of the equivalent plane crack of the component; ;in, represents the depth of the equivalent plane crack of the component, represents the plane crack geometry correction factor, Indicates the depth of the crack pit in the component, Indicates the width of the pit in a crack in a component.

[0011] Optionally, based on the equivalent crack size of each component, the characteristic parameters of the crack, the far-field stress of the crack and the geometric correction factor of the crack, the stress intensity factor of the crack of each component is obtained, including: For each component: The equivalent crack size of the component, the characteristic parameters of the crack, the geometric correction factor, and the far-field stress of the crack are calculated using the following formula to obtain the stress intensity factor of the crack of each component; ;in, The stress intensity factor representing the crack in the component, represents the far-field stress of the crack, represents pi, represents the equivalent crack size of the component, A geometric correction factor representing cracks in a component.

[0012] Optionally, based on the maximum stress intensity factor, the minimum stress intensity factor, the first preset material constant and the second preset material constant of the crack of each component, the crack propagation rate of each component is obtained, including: For each component: The maximum stress intensity factor, the minimum stress intensity factor, the first preset material constant and the second preset material constant of the crack of the component are calculated using the following formula to obtain the crack propagation rate of the component; ;in, Indicates the crack growth rate of the component, a first predetermined material constant representing a crack in the component, The maximum stress intensity factor representing a crack in a component, The minimum stress intensity factor for a crack in a component is, A second predetermined material constant representing a crack in the component.

[0013] Optionally, based on the expected life and average life of each component, the failure probability of each component is obtained, including: For each component: The expected life and average life of a component are calculated using the following formula to obtain the failure probability of the component; ;in, represents the failure probability of a component, Indicates the expected life of the component, Indicates the average life of a component.

[0014] Optionally, determining the risk level score of each treatment measure for each component to be evaluated includes: For each component: Matching each treatment measure of the crack of the component to be evaluated with a pre-constructed risk level score table to obtain a severity score, an occurrence probability score, and a detection probability score of each treatment measure of the crack of the component to be evaluated; wherein the pre-constructed risk level score table is used to characterize the mapping relationship between the treatment measure of the crack of the component to be evaluated and the severity score, the occurrence probability score, and the detection probability score; The product of the severity score, the occurrence probability score and the detection probability score of each treatment measure for the crack of the component to be evaluated is calculated to obtain the risk level score of each treatment measure for the crack of the component to be evaluated.

[0015] Optionally, the turbine component crack operation and maintenance method further includes: For each component: If the weight distribution coefficient of the component is less than the preset weight distribution coefficient, the component is controlled to stop running after a first preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient and the stress intensity factor is less than the preset stress intensity factor, controlling the component to stop running after a second preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, and the expansion rate is less than the first preset expansion rate, then the component is controlled to stop running after a third preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, and the expansion rate is greater than the second preset expansion rate, the control component stops running immediately; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, the expansion rate is greater than the first preset expansion rate and less than the second preset expansion rate, and the failure probability is less than the preset failure probability, then the component is controlled to stop running after the fourth preset running time; Among them, the first preset running time>the second preset running time>the third preset running time>the fourth preset running time.

[0016] Beneficial effects of the present invention: (1) Accurate analysis and evaluation: The operating parameters, crack characteristic parameters and far-field stress of turbine components are obtained, and the weight distribution coefficient, stress intensity factor, expansion rate and failure probability are determined through force analysis. The component condition is comprehensively and accurately evaluated to provide a scientific basis for decision-making, which is more scientific and accurate than traditional judgment based on experience or a single factor.

[0017] (2) Screening of key components: Determine the components to be evaluated according to the set parameter standards, focus on the key points, avoid indiscriminate treatment, improve operation and maintenance efficiency, and save time and resources.

[0018] (3) Optimize treatment strategy: Obtain the treatment measures and cost-effectiveness net present value of the components to be evaluated, determine the risk level score, find the target treatment measures with the lowest risk and the required cost-effectiveness net present value, take into account both risk and cost-effectiveness, and avoid excessive or insufficient treatment.

[0019] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 It is a schematic flow chart of a method for operating and maintaining cracks in a turbine component provided by an embodiment of the present invention; Figure 2 It is a flow chart of a method for operating and maintaining cracks in a turbine component provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0021] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0023] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0024] Embodiment 1 Please refer to Figure 1 and 2 The present invention provides a method for operating and maintaining cracks in a turbine component, the method comprising the following steps: S100, obtaining operating parameters of multiple components of the turbine, characteristic parameters of the crack, and far-field stress of the crack; The operating parameters of the components of the water turbine include: a plurality of evaluation indicators of the components of the water turbine, the expected life of the components of the water turbine and the average life of the components of the water turbine.

[0025] The multiple evaluation indicators of turbine components refer to standards for measuring component performance and reliability from different angles, including but not limited to: reliability, cost, maintenance requirements, impact on efficiency, material strength, durability, and ability to control water flow, etc.

[0026] The expected life of turbine components refers to the length of time that the components can work normally until they need to be replaced, predicted through calculations and experiments during the design phase based on factors such as material properties, design structure, and operating conditions.

[0027] The average life of turbine components refers to the average of the actual service life of turbine components used under a large number of the same or similar working conditions. This data is usually derived from historical statistical data or on-site follow-up surveys, reflecting the durability of components under actual conditions.

[0028] The far-field stress of a crack in a turbine component refers to the stress far away from the front end of the crack. These stresses are usually uniformly distributed and are the stresses that the component is subjected to when there is no crack.

[0029] For ease of understanding, multiple evaluation indicators of components of a water turbine are given as examples below, as shown in Table 1 below: Table 1 Evaluation indexes of turbine components

[0030] For ease of understanding, the expected life of components of a water turbine, the average life of components of a water turbine, and the far-field stress of cracks of components of a water turbine are given as examples below, as shown in Table 2 below: Table 2 Parameters of turbine components

[0031] It is understandable that, since cracks have different shapes, the characteristic parameters of cracks of different shapes are also different. For example, the characteristic parameters of a circular crack only include the radius, while the characteristic parameters of an elliptical crack include the major axis radius and the minor axis radius.

[0032] In one embodiment, different crack shapes have different characteristic parameters of the crack, including: If the crack shape is a circular crack, the characteristic parameters of the crack include the area of ​​the crack; If the crack shape is an elliptical crack, the characteristic parameters of the crack include the major axis radius and the minor axis radius of the crack; If the crack shape is a through crack, the characteristic parameters of the crack include the width and depth of the crack; If the shape of the crack is an edge crack, the characteristic parameters of the crack include the pit depth and pit width of the crack.

[0033] The characteristic parameters of the crack are given as an example below, as shown in Table 3 below: Table 3 Characteristic parameters of cracks in turbines

[0034] S200, performing stress analysis on each component based on operating parameters of each component, characteristic parameters of the crack, and far-field stress of the crack, and determining a weight distribution coefficient of each component, a stress intensity factor of the crack, a crack propagation rate, and a failure probability; In one embodiment, step S200 includes: S210, obtaining a weight distribution coefficient of each component based on multiple evaluation indicators of each component; Specifically, step S210 includes: S211, using the following formula, normalizing each evaluation index of each component to obtain each evaluation index of each component after normalization; Specifically, the maximum value of each evaluation index, the minimum value of each evaluation index and each evaluation index of each component are calculated using the following formula to obtain each evaluation index of each component after normalization; ;in, represents the jth evaluation index of the i-th component after normalization, represents the jth evaluation index of the i-th component, represents the maximum value of the jth evaluation index, represents the minimum value of the jth evaluation index; For ease of understanding, the evaluation indicators of each component after normalization are calculated based on the data in Table 1 above, as shown in Table 4 below: Table 4 Multiple evaluation indicators of turbine components after normalization

[0035] S212, using the following formula, calculating each evaluation index of each component after normalization to obtain the weight of each evaluation index of each component; ;in, represents the jth evaluation index of the i-th component, Indicates the number of parts; S213, using the following formula, calculating the weight of each evaluation index of each component to obtain the information entropy of each evaluation index; ;in, represents the information entropy of the jth evaluation index; S214, using the following formula, calculating the information entropy of each evaluation indicator to obtain the effective information amount of each evaluation indicator; ;in, Indicates the effective information amount of each evaluation index; For ease of understanding, after the normalized index data in Table 2 are combined for specific gravity calculation, the specific gravity is calculated according to step S213 to obtain the information entropy of each evaluation index, and then the information entropy of each evaluation index is calculated according to step S214 to obtain the difference coefficient of each evaluation index, as shown in Table 5 below: Table 5 Information entropy and difference coefficient of evaluation indexes of turbines

[0036] S215, using the following formula, calculate the effective information amount of each evaluation index to obtain the weight distribution coefficient of each component; ;in, represents the weight distribution coefficient of the i-th component, and n represents the number of evaluation indicators.

[0037] For ease of understanding, the weight distribution coefficients of each component can be obtained by combining the information entropy and difference coefficient of each evaluation index in Table 3 above, as shown in Table 6 below: Table 6 Weight distribution coefficients of turbine components

[0038] S220, obtaining an equivalent crack size and a geometric correction factor of each component based on characteristic parameters of the crack of each component; It is understandable that, as mentioned above, since cracks have different shapes and the characteristic parameters of cracks of different shapes are also different, cracks of different shapes have different equivalent crack sizes and geometric correction factors.

[0039] The equivalent crack size includes: the radius of the equivalent circular crack, the radius of the equivalent elliptical crack, the depth of the equivalent penetrating crack and the depth of the equivalent plane crack.

[0040] The geometric correction factors include: circular crack geometric correction factor, elliptical crack geometric correction factor, penetrating crack geometric correction factor and plane crack geometric correction factor.

[0041] Specifically, step S220 includes: For each component: S221, if the shape of the crack is a circular crack, use the following formula to calculate the area of ​​the crack of the component to obtain the radius of the equivalent circular crack of the component, and use a preset constant as a circular crack geometry correction factor; ;in, represents the radius of the equivalent circular crack of the component, represents the circular crack geometry correction factor, Indicates the area of ​​the crack in the component, represents pi; S222, if the shape of the crack is an elliptical crack, use the following formula to calculate the major axis radius and the minor axis radius of the crack of the component to obtain the radius of the equivalent elliptical crack of the component and the elliptical crack geometric correction factor; ;in, represents the radius of the equivalent elliptical crack of the component, represents the geometric correction factor for elliptical cracks, represents the major axis radius of the crack in the component, The minor axis radius of the crack representing the component; S223, if the shape of the crack is a penetrating crack, the width and depth of the crack of the component are calculated using the following formula to obtain the depth of the equivalent penetrating crack of the component; ;in, Indicates the depth of the equivalent through-crack of the component, represents the geometric correction factor of penetrating cracks, Indicates the depth of the crack in the component, Indicates the width of the crack in the component; S224, if the shape of the crack is an edge crack, the pit depth and pit width of the crack of the component are calculated using the following formula to obtain the depth of the equivalent plane crack of the component; ;in, represents the depth of the equivalent plane crack of the component, represents the plane crack geometry correction factor, Indicates the depth of the crack pit in the component, Indicates the width of the pit in a crack in a component.

[0042] For ease of understanding, the equivalent crack sizes and geometric correction factors of different crack types of turbine components can be obtained by combining the data in Table 3 above, as shown in Table 7 below: Table 7 Crack size of turbine components

[0043] S230, obtaining a stress intensity factor of the crack of each component based on an equivalent crack size of each component, a characteristic parameter of the crack, a far-field stress of the crack, and a geometric correction factor of the crack; Specifically, step S230 includes: For each component: The equivalent crack size of the component, the characteristic parameters of the crack, the geometric correction factor, and the far-field stress of the crack are calculated using the following formula to obtain the stress intensity factor of the crack of each component; ;in, The stress intensity factor representing the crack in the component, represents the far-field stress of the crack, represents pi, represents the equivalent crack size of the component, A geometric correction factor representing cracks in a component.

[0044] For ease of understanding, the stress intensity factors of cracks in various components of the turbine are calculated by combining the data in Table 7 above, as shown in Table 8 below: Table 8 Stress intensity factors of cracks in various components of turbines

[0045] S240, obtaining a maximum stress intensity factor of the crack of each component and a minimum stress intensity factor of the crack of each component based on a preset maximum far-field stress of each component and a preset minimum far-field stress of the crack, and based on an equivalent crack size of each component, a characteristic parameter of the crack and a geometric correction factor; It is understandable that step S240 is consistent with step S230 in calculation logic, except that the far-field stress of the crack is replaced by the maximum far-field stress of the crack and the minimum far-field stress of the crack, and other parameter values ​​remain unchanged, so that the maximum stress intensity factor of the crack of each component and the minimum stress intensity factor of the crack of each component can be calculated, which will not be repeated here.

[0046] S250, obtaining a crack propagation rate of each component based on a maximum stress intensity factor, a minimum stress intensity factor, a first preset material constant, and a second preset material constant of the crack of each component; Specifically, step S250 includes: For each component: The maximum stress intensity factor, the minimum stress intensity factor, the first preset material constant and the second preset material constant of the crack of the component are calculated using the following formula to obtain the crack propagation rate of the component; ;in, Indicates the crack growth rate of the component, a first predetermined material constant representing a crack in the component, The maximum stress intensity factor representing a crack in a component, The minimum stress intensity factor for a crack in a component is, A second predetermined material constant representing a crack in the component.

[0047] For ease of understanding, the maximum stress intensity factor, the minimum stress intensity factor, the first preset material constant and the second preset material constant of cracks of components of a water turbine are given as an example below, as shown in the following Table 9: Table 9 Calculation parameters of stress intensity of cracks in turbine components

[0048] S260, based on the expected life and average life of each component, obtain the failure probability of each component.

[0049] Specifically, step S260 includes: For each component: The expected life and average life of a component are calculated using the following formula to obtain the failure probability of the component; ;in, represents the failure probability of a component, Indicates the expected life of the component, Indicates the average life of a component.

[0050] For ease of understanding, the failure probability of each component of the turbine is calculated by combining the data in Table 2, as shown in Table 10 below: Table 10 Failure probability calculation parameters of turbine components

[0051] S300, determining that a component whose weight distribution coefficient is greater than a preset weight distribution coefficient, whose stress intensity factor is greater than a preset stress intensity factor, whose expansion rate is greater than a first preset expansion rate and less than a second preset expansion rate, and whose failure probability is greater than a preset failure probability is a component to be evaluated; For ease of understanding, the following examples are given in conjunction with the data in Tables 6, 8, 9 and 10: Assume that the preset weight distribution coefficient is 0.12, the preset stress intensity factor is 300MPa√m, and the first preset expansion rate is 10 -4 mm / cycle, the second preset expansion rate is 10 -6 mm / cycle, and the default failure probability is 0.5.

[0052] Guide vane 1 (crack): The weight distribution coefficient is 0.1374, which is greater than the preset value of 0.12; the stress intensity factor is 300.51 MPa√m, which is greater than the preset value of 300 MPa√m; the expansion rate is 2×10 -8 m / cycle, at the first preset expansion rate of 10 -7 m / cycle and second default expansion rate 10 -9 m / cycle; the failure probability is 0.55, which is greater than the preset 0.5. This component meets all the set conditions, so the guide vane 1 (crack) is the component to be evaluated.

[0053] Guide vane 2: The weight distribution coefficient is 0.1540, which is greater than the preset value of 0.12, but the stress intensity factor is 250.30 MPa√m, which is less than the preset value of 300 MPa√m. It does not meet the condition that "the stress intensity factor is greater than the preset stress intensity factor", so guide vane 2 is not a component to be evaluated.

[0054] Guide vane 3: The weight distribution coefficient is 0.1112, which is less than the preset 0.12 and does not meet the condition that “the weight distribution coefficient is greater than the preset weight distribution coefficient”, so guide vane 3 is not a component to be evaluated.

[0055] Guide vane 4: The weight distribution coefficient is 0.1004, which is less than the preset weight distribution coefficient of 0.12 and does not meet the condition that “the weight distribution coefficient is greater than the preset weight distribution coefficient”, so the guide vane 4 is not a component to be evaluated.

[0056] Guide vane 5: The weight distribution coefficient is 0.1167, which is less than the preset 0.12 and does not meet the condition that “the weight distribution coefficient is greater than the preset weight distribution coefficient”, so guide vane 5 is not a component to be evaluated.

[0057] Other component 1: The weight distribution coefficient is 0.1332, which is greater than the preset 0.12, but the stress intensity factor is 270.32MPa√m, which is less than the preset 300MPa√m. It does not meet the condition of "the stress intensity factor is greater than the preset stress intensity factor", so other component 1 is not a component to be evaluated.

[0058] Other components 2: The weight distribution coefficient is 0.1391, which is greater than the preset 0.12, but the stress intensity factor is 260.28MPa√m, which is less than the preset 300MPa√m. It does not meet the condition of "the stress intensity factor is greater than the preset stress intensity factor", so other components 2 are not components to be evaluated.

[0059] Other component 3: The weight distribution coefficient is 0.1080, which is less than the preset 0.12 and does not meet the condition of "the weight distribution coefficient is greater than the preset weight distribution coefficient", so other component 3 is not a component to be evaluated.

[0060] S400, obtaining multiple treatment measures for the component to be evaluated and the cost-effectiveness net present values ​​of the multiple treatment measures; The treatment measures for turbine components refer to a series of operating methods and means adopted to ensure the normal operation, improve performance and extend service life of various turbine components in response to different conditions that arise during their operation.

[0061] The cost-benefit net present value of turbine components is an important indicator used to evaluate whether a turbine component investment project is economically feasible. It reflects the actual economic value of the project by considering the cost and benefits of the project throughout its life cycle and discounting the future cash flow to the current moment at a certain discount rate.

[0062] It should be noted that the treatment measures for various components of the turbine may be consistent or inconsistent, and the embodiment of the present invention does not specifically limit this.

[0063] The following exemplary treatment measures for cracks in components of a water turbine are given as shown in Table 11 below: Table 11 Treatment measures for cracks in turbine components

[0064] In one embodiment, the cost-benefit net present value can be calculated by the following formula: ;in, represents the net present value of cost-benefit, represents the income in year t, represents the cost in year t, Represents the discount rate.

[0065] For ease of understanding, the following example is given in conjunction with Table 12: Table 12 Parameters for calculating the cost-effectiveness net present value of treatment measures

[0066] S500, determining the risk level score of each treatment measure of each component to be evaluated, and determining the treatment measure with the minimum risk level score of each component to be evaluated and the cost-benefit net present value greater than a preset threshold as the target treatment measure for each component to be evaluated; In one embodiment, determining the risk level score of each treatment measure for each component to be evaluated includes: For each component: S510, matching each treatment measure of the crack of the component to be evaluated with a pre-constructed risk level score table to obtain a severity score, an occurrence probability score, and a detection probability score of each treatment measure of the crack of the component to be evaluated; wherein the pre-constructed risk level score table is used to characterize the mapping relationship between the treatment measure of the crack of the component to be evaluated and the severity score, the occurrence probability score, and the detection probability score; Table 12 Pre-built risk level score table

[0067] It is understandable that the severity score, occurrence probability score and detection probability score of the treatment measures for cracks of a certain component are given here only as examples.

[0068] S520, calculating the product of the severity score, the occurrence probability score and the detection probability score of each treatment measure for the crack of the component to be evaluated, and obtaining the risk level score of each treatment measure for the crack of the component to be evaluated.

[0069] For ease of understanding, the following is an example of calculation based on Table 12 above: Measure 1: 7*4*5=140; Measure 2: 8*3*4=96; Measure 3: 6*5*3=90.

[0070] Specifically, taking guide vane 1 (crack) as an example, its cost-benefit net present value is 649,200 yuan, which is greater than 0, and the risk level score of measure 3 among the three treatment measures for guide vane 1 (crack) is 90 points, which is the smallest score, so measure 3 is taken as the target treatment measure for guide vane 1 (crack).

[0071] S600: Send the target processing measures of each component to be evaluated to the user's terminal device, so that the user can maintain each component to be evaluated according to the target processing measures of each component to be evaluated.

[0072] In one or more of the above embodiments, the turbine component crack operation and maintenance method further includes: For each component: If the weight distribution coefficient of the component is less than the preset weight distribution coefficient, the component is controlled to stop running after a first preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient and the stress intensity factor is less than the preset stress intensity factor, controlling the component to stop running after a second preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, and the expansion rate is less than the first preset expansion rate, then the component is controlled to stop running after a third preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, and the expansion rate is greater than the second preset expansion rate, the control component stops running immediately; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, the expansion rate is greater than the first preset expansion rate and less than the second preset expansion rate, and the failure probability is less than the preset failure probability, then the component is controlled to stop running after the fourth preset running time; Among them, the first preset running time>the second preset running time>the third preset running time>the fourth preset running time.

[0073] For ease of understanding, the following examples are given in conjunction with the data in Tables 6, 7, 8 and 9: like Figure 2 As shown, it is assumed that the first preset time length is one week, the second preset time length is 72 hours, the third preset time length is 48 hours, and the fourth preset time length is 24 hours.

[0074] (1) Guide vane 1 (crack): Weight coefficient: 0.1374, which is greater than the preset weight distribution coefficient of 0.12.

[0075] Stress intensity factor: 300.51MPa√m, which is greater than the preset stress intensity factor of 300MPa√m.

[0076] Expansion rate: 2×10⁻ 8 m / cycle, at the first preset expansion rate of 10⁻ 7 m / cycle and second preset expansion rate 10⁻ 9 m / cycle.

[0077] Failure probability: 0.55, which is greater than the preset failure probability of 0.5.

[0078] Handling method: Marked as a part to be evaluated.

[0079] (2) Guide vane 2: Weight coefficient: 0.1540, which is greater than the preset weight distribution coefficient of 0.12.

[0080] Stress intensity factor: 250.30MPa√m, which is less than the preset stress intensity factor of 300MPa√m.

[0081] Treatment method: The control components stop operating after 72 hours of operation.

[0082] (3) Guide vane 3: Weight coefficient: 0.1112, which is less than the preset weight distribution coefficient of 0.12.

[0083] Solution: The control component stops operating after running for one week.

[0084] (4) Guide vane 4: Weight coefficient: 0.1004, which is less than the preset weight distribution coefficient of 0.12.

[0085] Solution: The control component stops running after one week of operation.

[0086] (5) Guide vane 5: Weight coefficient: 0.1167, which is less than the preset weight distribution coefficient of 0.12.

[0087] Solution: The control component stops running after one week of operation.

[0088] (6) Other parts 1: Weight coefficient: 0.1332, which is greater than the preset weight distribution coefficient of 0.12.

[0089] Stress intensity factor: 270.32MPa√m, which is less than the preset stress intensity factor of 300MPa√m.

[0090] Treatment method: The control components stop operating after 72 hours of operation.

[0091] (7) Other parts 2: Weight coefficient: 0.1391, which is greater than the preset weight distribution coefficient of 0.12.

[0092] Stress intensity factor: 260.28MPa√m, which is less than the preset stress intensity factor of 300MPa√m.

[0093] Treatment method: The control components stop operating after 72 hours of operation.

[0094] (8) Other parts 3: Weight coefficient: 0.1080, which is less than the preset weight distribution coefficient of 0.12.

[0095] Solution: The control component stops running after one week of operation.

[0096] Beneficial effects of the present invention: (1) Accurate analysis and evaluation: The operating parameters, crack characteristic parameters and far-field stress of turbine components are obtained, and the weight distribution coefficient, stress intensity factor, expansion rate and failure probability are determined through force analysis. The component condition is comprehensively and accurately evaluated to provide a scientific basis for decision-making, which is more scientific and accurate than traditional judgment based on experience or a single factor.

[0097] (2) Screening of key components: Determine the components to be evaluated according to the set parameter standards, focus on the key points, avoid indiscriminate treatment, improve operation and maintenance efficiency, and save time and resources.

[0098] (3) Optimize treatment strategy: Obtain the treatment measures and cost-effectiveness net present value of the components to be evaluated, determine the risk level score, find the target treatment measures with the lowest risk and the required cost-effectiveness net present value, take into account both risk and cost-effectiveness, and avoid excessive or insufficient treatment.

[0099] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0100] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for operating and maintaining cracks in turbine components, characterized in that: include: Obtaining operating parameters of multiple components of the turbine, characteristic parameters of cracks and far-field stress of cracks; Based on the operating parameters of each component, the characteristic parameters of the crack and the far-field stress of the crack, the stress analysis of each component is carried out to determine the weight distribution coefficient of each component, the stress intensity factor of the crack, the crack propagation rate and the failure probability; Determine that a component whose weight distribution coefficient is greater than a preset weight distribution coefficient, whose stress intensity factor is greater than a preset stress intensity factor, whose expansion rate is greater than a first preset expansion rate and less than a second preset expansion rate, and whose failure probability is greater than a preset failure probability is a component to be evaluated; Obtain multiple treatment measures and cost-effectiveness net present values ​​of the multiple treatment measures for the component to be evaluated; Determine the risk level score of each treatment measure for each component to be evaluated, and determine the minimum risk level score of each component to be evaluated, and the treatment measure with a cost-effectiveness net present value greater than a preset threshold is the target treatment measure for each component to be evaluated; The target processing measures of each component to be evaluated are sent to the user's terminal device, so that the user can maintain each component to be evaluated according to the target processing measures of each component to be evaluated.

2. The method for operating and maintaining cracks in turbine components according to claim 1, characterized in that: Operational parameters include: multiple evaluation indicators, life expectancy and average lifespan; Different crack shapes have different characteristic parameters of cracks, including: If the crack shape is a circular crack, the characteristic parameters of the crack include the area of ​​the crack; If the crack shape is an elliptical crack, the characteristic parameters of the crack include the major axis radius and the minor axis radius of the crack; If the crack shape is a through crack, the characteristic parameters of the crack include the width and depth of the crack; If the shape of the crack is an edge crack, the characteristic parameters of the crack include the pit depth and pit width of the crack.

3. The method for operating and maintaining cracks in turbine components according to claim 2, characterized in that: Based on the operating parameters of each component, the characteristic parameters of the crack and the far-field stress of the crack, the stress analysis of each component is carried out to determine the weight distribution coefficient of each component, the stress intensity factor of the crack, the crack propagation rate and the failure probability, including: Based on multiple evaluation indicators of each component, a weight distribution coefficient of each component is obtained; Based on the characteristic parameters of the cracks of each component, the equivalent crack size and geometric correction factor of each component are obtained; Based on the equivalent crack size of each component, the characteristic parameters of the crack, the far-field stress of the crack and the geometric correction factor of the crack, the stress intensity factor of the crack of each component is obtained; Based on the preset maximum far-field stress of each component and the preset minimum far-field stress of the crack, as well as the equivalent crack size of each component, the characteristic parameters of the crack and the geometric correction factor, the maximum stress intensity factor of the crack of each component and the minimum stress intensity factor of the crack of each component are obtained; Based on the maximum stress intensity factor, the minimum stress intensity factor, the first preset material constant and the second preset material constant of the crack of each component, the crack propagation rate of each component is obtained; Based on the expected life and average life of each component, the failure probability of each component is obtained.

4. The method for operating and maintaining cracks in turbine components according to claim 3, characterized in that: Based on multiple evaluation indicators of each component, the weight distribution coefficient of each component is obtained, including: The maximum value of each evaluation index, the minimum value of each evaluation index and each evaluation index of each component are normalized using the following formula to obtain each evaluation index of each component after normalization; The following formula is used to calculate the evaluation index of each component after normalization to obtain the weight of each evaluation index of each component; ;in, represents the jth evaluation index of the i-th component, Indicates the number of parts, represents the jth evaluation index of the i-th component after normalization; The following formula is used to calculate the weight of each evaluation index of each component to obtain the information entropy of each evaluation index; ;in, represents the information entropy of the jth evaluation index; The information entropy of each evaluation index is calculated using the following formula to obtain the effective information amount of each evaluation index; ;in, Indicates the effective information amount of each evaluation index; Use the following formula to calculate the effective information volume of each evaluation index and obtain the weight distribution coefficient of each component; ;in, represents the weight distribution coefficient of the i-th component, and n represents the number of evaluation indicators.

5. The method for operating and maintaining cracks in turbine components according to claim 3, characterized in that: The equivalent crack size includes: the radius of the equivalent circular crack, the radius of the equivalent elliptical crack, the depth of the equivalent penetrating crack and the depth of the equivalent plane crack; The geometric correction factors include: circular crack geometric correction factor, elliptical crack geometric correction factor, penetrating crack geometric correction factor and plane crack geometric correction factor; Based on the characteristic parameters of the cracks of each component, the equivalent crack size and geometric correction factor of each component are obtained, including: For each component: If the shape of the crack is a circular crack, the area of ​​the crack of the component is calculated using the following formula to obtain the radius of the equivalent circular crack of the component, and the preset constant is used as the circular crack geometry correction factor; ;in, represents the radius of the equivalent circular crack of the component, represents the circular crack geometry correction factor, Indicates the area of ​​the crack in the component, represents pi; If the shape of the crack is an elliptical crack, the major axis radius and the minor axis radius of the crack of the component are calculated using the following formula to obtain the radius of the equivalent elliptical crack of the component and the elliptical crack geometric correction factor; ;in, represents the radius of the equivalent elliptical crack of the component, represents the geometric correction factor for elliptical cracks, represents the major axis radius of the crack in the component, The minor axis radius of the crack representing the component; If the crack shape is a penetrating crack, the width and depth of the crack of the component are calculated using the following formula to obtain the depth of the equivalent penetrating crack of the component; ;in, Indicates the depth of the equivalent through-crack of the component, represents the geometric correction factor of penetrating cracks, Indicates the depth of the crack in the component, Indicates the width of the crack in the component; If the shape of the crack is an edge crack, the pit depth and pit width of the crack of the component are calculated using the following formula to obtain the depth of the equivalent plane crack of the component; ;in, represents the depth of the equivalent plane crack of the component, represents the plane crack geometry correction factor, Indicates the depth of the crack pit in the component, Indicates the width of the pit in a crack in a component.

6. The method for operating and maintaining cracks in turbine components according to claim 3, characterized in that: Based on the equivalent crack size of each component, the characteristic parameters of the crack, the far-field stress of the crack and the geometric correction factor of the crack, the stress intensity factor of the crack of each component is obtained, including: For each component: The equivalent crack size of the component, the characteristic parameters of the crack, the geometric correction factor, and the far-field stress of the crack are calculated using the following formula to obtain the stress intensity factor of the crack of each component; ;in, The stress intensity factor representing the crack in the component, represents the far-field stress of the crack, represents pi, represents the equivalent crack size of the component, A geometric correction factor representing cracks in a component.

7. The method for operating and maintaining cracks in turbine components according to claim 3, characterized in that: Based on the maximum stress intensity factor, the minimum stress intensity factor, the first preset material constant and the second preset material constant of the crack of each component, the crack propagation rate of each component is obtained, including: For each component: The maximum stress intensity factor, the minimum stress intensity factor, the first preset material constant and the second preset material constant of the crack of the component are calculated using the following formula to obtain the crack propagation rate of the component; ;in, Indicates the crack growth rate of the component, a first predetermined material constant representing a crack in the component, The maximum stress intensity factor representing a crack in a component, The minimum stress intensity factor for a crack in a component is, A second predetermined material constant representing a crack in the component.

8. The method for operating and maintaining cracks in turbine components according to claim 3, characterized in that: Based on the expected life and average life of each component, the failure probability of each component is obtained, including: For each component: The expected life and average life of a component are calculated using the following formula to obtain the failure probability of the component; ;in, represents the failure probability of a component, Indicates the expected life of the component, Indicates the average life of a component.

9. The method for operating and maintaining cracks in turbine components according to claim 1, characterized in that: Determine the risk level score for each treatment measure for each component to be evaluated, including: For each component: Matching each treatment measure of the crack of the component to be evaluated with a pre-constructed risk level score table to obtain a severity score, an occurrence probability score, and a detection probability score of each treatment measure of the crack of the component to be evaluated; wherein the pre-constructed risk level score table is used to characterize the mapping relationship between the treatment measure of the crack of the component to be evaluated and the severity score, the occurrence probability score, and the detection probability score; The product of the severity score, the occurrence probability score and the detection probability score of each treatment measure for the crack of the component to be evaluated is calculated to obtain the risk level score of each treatment measure for the crack of the component to be evaluated.

10. The method for operating and maintaining cracks in turbine components according to claim 1, characterized in that: The method further comprises: For each component: If the weight distribution coefficient of the component is less than the preset weight distribution coefficient, the component is controlled to stop running after a first preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient and the stress intensity factor is less than the preset stress intensity factor, controlling the component to stop running after a second preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, and the expansion rate is less than the first preset expansion rate, then the component is controlled to stop running after a third preset running time; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, and the expansion rate is greater than the second preset expansion rate, the control component stops running immediately; If the weight distribution coefficient of the component is greater than the preset weight distribution coefficient, the stress intensity factor is greater than the preset stress intensity factor, the expansion rate is greater than the first preset expansion rate and less than the second preset expansion rate, and the failure probability is less than the preset failure probability, then the component is controlled to stop running after the fourth preset running time; Among them, the first preset running time>the second preset running time>the third preset running time>the fourth preset running time.

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