Method for operating and maintaining cracks in turbine components

Abstract

The application provides a kind of water turbine component crack operation and maintenance method, belongs to water turbine crack maintenance technical field.The method includes: obtaining water turbine component operating parameter, crack characteristics and far field stress, and determining weight distribution coefficient, stress intensity factor and the like by stress analysis.Screen out the components to be evaluated whose weight distribution coefficient, stress intensity factor and the like meet specific conditions, obtain their treatment measures and cost-benefit net present value, determine the risk level score of each measure, and select the minimum risk level score and cost-benefit net present value exceeding the threshold value as the target treatment measure.Finally, the target treatment measure is issued to the user terminal, so that the user can maintain the component.The application accurately evaluates the condition of water turbine component by obtaining relevant parameters and stress analysis, provides a scientific basis for decision-making, also screens key components according to various parameter standards, improves operation and maintenance efficiency, and can also determine the target treatment measure by comprehensively considering risk and cost-benefit, to avoid over-treatment or insufficient treatment.

Description

Technical Field

[0001] The present 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] Turbine metal components are crucial for the stable and efficient operation of power generation systems. Over extended periods of operation, they are susceptible to damage such as cracks due to mechanical stress and hydraulic erosion. Cracks seriously impact component integrity and increase safety risks, necessitating prompt assessment and treatment upon discovery. However, in actual turbine operation, the timing of crack treatment is constrained by various factors, including unplanned maintenance periods, peak power demand, economic considerations, and the need for water level regulation during flood seasons.

[0003] Currently, traditional inspection methods such as ultrasonic testing, magnetic particle testing, penetrant testing, and radiographic testing can effectively detect cracks on and within components. Furthermore, with technological advancements, advanced real-time monitoring technologies are increasingly being applied to turbine operation. For example, integrated real-time monitoring systems can monitor cracks in real time without shutting down the equipment. When it comes to crack treatment, the common approach is to develop appropriate measures based on experience and rough assessments, such as repairing cracks or replacing damaged components.

[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 effects 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 optimal and 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] To achieve the above objectives, an embodiment of the present invention provides a method for operating and maintaining cracks in a hydraulic turbine component, comprising:

[0007] Obtaining operating parameters of multiple components of the turbine, characteristic parameters of cracks, and far-field stresses of cracks;

[0008] 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 growth rate and the failure probability;

[0009] Determine as a component to be evaluated 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;

[0010] Obtain multiple treatment measures and cost-effectiveness net present values ​​of the components to be evaluated;

[0011] 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 net present value of cost-effectiveness greater than a preset threshold is the target treatment measure for each component to be evaluated;

[0012] 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.

[0013] Optionally, the operating parameters include: multiple evaluation indicators, life expectancy and average lifespan;

[0014] Different crack shapes have different characteristic parameters of cracks, including:

[0015] If the crack shape is a circular crack, the characteristic parameters of the crack include the area of ​​the crack;

[0016] 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;

[0017] If the crack shape is a penetrating crack, the characteristic parameters of the crack include the width and depth of the crack;

[0018] 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.

[0019] Optionally, a stress analysis is performed on each component based on the operating parameters of each component, the characteristic parameters of the crack, and the far-field stress of the crack to determine the weight distribution coefficient of each component, the stress intensity factor of the crack, the crack growth rate, and the failure probability, including:

[0020] Based on multiple evaluation indicators of each component, a weight distribution coefficient of each component is obtained;

[0021] Based on the characteristic parameters of the cracks of each component, the equivalent crack size and geometric correction factor of each component are obtained;

[0022] 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;

[0023] 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 preset maximum far-field stress of each component and the preset minimum far-field stress of the crack, and based on the equivalent crack size of each component, the characteristic parameter of the crack and the geometric correction factor;

[0024] The crack propagation rate of each component is obtained based on the maximum stress intensity factor of the crack of each component, the minimum stress intensity factor of the crack of each component, the first preset material constant and the second preset material constant.

[0025] The failure probability of each component is obtained based on the expected life of each component and the average life.

[0026] Optionally, the weight distribution coefficient of each component is obtained based on a plurality of evaluation indexes of each component, including:

[0027] The maximum value of each evaluation index, the minimum value of each evaluation index and each evaluation index of each component are normalized by using the following formula to obtain the normalized each evaluation index of each component;

[0028] The proportion of each evaluation index of each component is calculated by using the following formula based on the normalized each evaluation index of each component;

[0029] ; wherein, represents the jth evaluation index of the ith component, represents the number of components, represents the jth evaluation index of the ith component after normalization;

[0030] The information entropy of each evaluation index is calculated by using the following formula based on the proportion of each evaluation index of each component;

[0031] ; wherein, represents the information entropy of the jth evaluation index;

[0032] The effective information amount of each evaluation index is calculated by using the following formula based on the information entropy of each evaluation index;

[0033] ; wherein, represents the effective information amount of each evaluation index;

[0034] The weight distribution coefficient of each component is calculated by using the following formula based on the effective information amount of each evaluation index;

[0035] ; wherein, represents the weight distribution coefficient of the ith component, and n represents the number of evaluation indexes.

[0036] 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;

[0037] 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;

[0038] 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:

[0039] For each component:

[0040] If the crack is circular, the area of ​​the crack in 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;

[0041] ;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;

[0042] If the crack shape is an elliptical crack, the major axis radius and 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;

[0043] ;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;

[0044] If 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 equivalent penetrating crack depth of the component;

[0045] ;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;

[0046] If the crack is an edge crack, the following formula is used to calculate the pit depth and pit width of the crack in the component to obtain the depth of the equivalent plane crack of the component;

[0047] ;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 in the component, Indicates the width of the crack in the component.

[0048] 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:

[0049] For each component:

[0050] The following formula is used to calculate 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 to obtain the stress intensity factor of the crack of each component;

[0051] ;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.

[0052] Optionally, obtaining the crack growth rate of each component 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 includes:

[0053] For each component:

[0054] 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 growth rate of the component;

[0055] ;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 the crack in the component, The minimum stress intensity factor for cracks in components is expressed as, A second predetermined material constant representing a crack in the component.

[0056] Optionally, the failure probability of each component is obtained based on the expected life and the average life of each component, including:

[0057] For each component:

[0058] The expected life and the average life of the component are calculated by using the following formula to obtain the failure probability of the component:

[0059] wherein, represents the failure probability of the component, represents the expected life of the component, represents the average life of the component.

[0060] Optionally, the risk level score of each treatment measure of each component to be evaluated is determined, including:

[0061] For each component:

[0062] The treatment measures of the crack of the component to be evaluated are matched with the pre-constructed risk level score table to obtain the severity score, the occurrence probability score and the detection probability score of the treatment measures of the crack of the component to be evaluated; wherein the pre-constructed risk level score table is used to represent the mapping relationship between the treatment measures of the crack of the component to be evaluated and the severity score, the occurrence probability score and the detection probability score;

[0063] The product of the severity score, the occurrence probability score and the detection probability score of the treatment measures of the crack of the component to be evaluated is calculated to obtain the risk level score of the treatment measures of the crack of the component to be evaluated.

[0064] Optionally, the water turbine component crack operation and maintenance method further includes:

[0065] For each component:

[0066] 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;

[0067] 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, the component is controlled to stop running after a second preset running time;

[0068] 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 a first preset expansion rate, the component is controlled to stop running after a third preset running time;

[0069] 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;

[0070] 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, the component is stopped running after the fourth preset running time.

[0071] Wherein, the first preset running time > the second preset running time > the third preset running time > the fourth preset running time.

[0072] The beneficial effects of the present application are:

[0073] (1) Precise analysis and evaluation: Obtain the operating parameters of the water turbine component, crack characteristic parameters and far-field stress, determine the weight distribution coefficient, stress intensity factor, expansion rate and failure probability through stress analysis, comprehensively and accurately evaluate the component condition, and provide scientific basis for decision-making, which is more scientific and accurate than traditional experience or single factor judgment.

[0074] (2) Screening of key components: Determine the components to be evaluated according to the set parameter standard, focus on the key points, avoid indiscriminate treatment, improve the operation and maintenance efficiency, and save time and resources.

[0075] (3) Optimize treatment strategy: Obtain the treatment measures and cost-benefit net present value of the component to be evaluated, determine the risk level score, find out the target treatment measures with the minimum risk and cost-benefit net present value, and consider the risk and cost-benefit, so as to avoid over-treatment or insufficient treatment.

[0076] Other features and advantages of the embodiments of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0077] The accompanying drawings are used to provide further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific embodiments, but do not constitute a limitation on the embodiments of the present application. In the drawings:

[0078] Figure 1 is a flowchart of the water turbine component crack operation and maintenance method provided by an embodiment of the present application;

[0079] Figure 2 is a flowchart of the water turbine component crack operation and maintenance method provided by another embodiment of the present application. DETAILED DESCRIPTION

[0080] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein 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.

[0081] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art 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.

[0082] In the description of the embodiments of this application, the technical terms "first," "second," etc. are used only to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise specifically defined.

[0083] Example 1

[0084] Please refer to Figure 1 and 2 The present invention provides a method for repairing cracks in turbine components, the method comprising the following steps:

[0085] S100, obtaining operating parameters of multiple components of the turbine, characteristic parameters of the crack, and far-field stress of the crack;

[0086] 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.

[0087] The multiple evaluation indicators of turbine components refer to standards for measuring component performance and reliability from different perspectives, including but not limited to: reliability, cost, maintenance requirements, impact on efficiency, material strength, durability, and ability to control water flow, etc.

[0088] The expected life of a turbine component refers to the length of time the component can operate normally until it needs to be replaced, as predicted through calculations and experiments during the design phase based on factors such as material properties, design structure, and operating conditions.

[0089] The average lifespan of turbine components refers to the average actual service life of turbine components used under a large number of identical or similar operating conditions. This data is usually derived from historical statistics or on-site follow-up surveys and reflects the durability of components under real-world conditions.

[0090] 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.

[0091] For ease of understanding, the following examples provide multiple evaluation indicators for components of a hydraulic turbine, as shown in Table 1:

[0092] Table 1 Evaluation indexes of turbine components

[0093]

[0094] For ease of understanding, the expected life of components of a hydraulic turbine, the average life of components of a hydraulic turbine, and the far-field stress of cracks in components of a hydraulic turbine are given as examples below, as shown in Table 2 below:

[0095] Table 2 Parameters of turbine components

[0096]

[0097] 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.

[0098] In one embodiment, different crack shapes have different characteristic parameters of the crack, including:

[0099] If the crack shape is a circular crack, the characteristic parameters of the crack include the area of ​​the crack;

[0100] 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;

[0101] If the crack shape is a penetrating crack, the characteristic parameters of the crack include the width and depth of the crack;

[0102] 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.

[0103] The characteristic parameters of the crack are given as an example below, as shown in Table 3 below:

[0104] Table 3 Characteristic parameters of turbine cracks

[0105]

[0106] S200, performing a stress analysis on each component based on operating parameters of each component, characteristic parameters of the crack, and far-field stress of the crack, to determine a weight distribution coefficient of each component, a stress intensity factor of the crack, a crack growth rate, and a failure probability;

[0107] In one embodiment, step S200 includes:

[0108] S210, obtaining a weight distribution coefficient for each component based on multiple evaluation indicators of each component;

[0109] Specifically, step S210 includes:

[0110] S211, using the following formula, normalize the evaluation index of each component to obtain the normalized evaluation index of each component;

[0111] 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;

[0112] ;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, Indicates the minimum value of the j-th evaluation index;

[0113] 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:

[0114] Table 4 Multiple evaluation indicators of turbine components after normalization

[0115]

[0116] 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;

[0117] ;in, represents the jth evaluation index of the i-th component, Indicates the number of components;

[0118] S213, using the following formula, calculate the weight of each evaluation index of each component to obtain the information entropy of each evaluation index;

[0119] ;in, represents the information entropy of the jth evaluation index;

[0120] S214, using the following formula to calculate the information entropy of each evaluation indicator to obtain the effective information volume of each evaluation indicator;

[0121] ;in, Indicates the effective information amount of each evaluation index;

[0122] For ease of understanding, after calculating the proportion of the normalized index data in Table 2 above, the information entropy of each evaluation index can be obtained by calculating the proportion according to step S213. Then, the information entropy of each evaluation index can be calculated according to step S214 to obtain the difference coefficient of each evaluation index, as shown in Table 5 below:

[0123] Table 5 Information entropy and difference coefficient of evaluation indicators of hydraulic turbines

[0124]

[0125] S215, using the following formula, calculate the effective information amount of each evaluation indicator to obtain the weight distribution coefficient of each component;

[0126] ;in, represents the weight distribution coefficient of the i-th component, and n represents the number of evaluation indicators.

[0127] For ease of understanding, the information entropy and difference coefficient of each evaluation index in Table 3 are combined to calculate the weight distribution coefficient of each component, as shown in Table 6 below:

[0128] Table 6 Weight distribution coefficients of turbine components

[0129]

[0130] S220, obtaining an equivalent crack size and a geometric correction factor of each component based on characteristic parameters of the crack of each component;

[0131] 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.

[0132] 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.

[0133] 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.

[0134] Specifically, step S220 includes:

[0135] For each component:

[0136] S221, if the crack is circular, calculate the area of ​​the crack of the component using the following formula to obtain the radius of the equivalent circular crack of the component, and use a preset constant as a circular crack geometry correction factor;

[0137] ;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;

[0138] S222. If the crack is elliptical, calculate the major axis radius and minor axis radius of the crack of the component using the following formula to obtain the radius of the equivalent elliptical crack of the component and the elliptical crack geometric correction factor.

[0139] ;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;

[0140] S223, if the crack is a penetrating crack, calculate the width and depth of the crack of the component using the following formula to obtain the equivalent penetrating crack depth of the component;

[0141] ;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;

[0142] S224, if the crack is an edge crack, calculate the pit depth and pit width of the crack in the component using the following formula to obtain the depth of the equivalent plane crack of the component;

[0143] ;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 in the component, Indicates the width of the crack in the component.

[0144] 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:

[0145] Table 7 Crack size of turbine components

[0146]

[0147] S230, obtaining a stress intensity factor of the crack of each component based on the equivalent crack size of each component, characteristic parameters of the crack, far-field stress of the crack, and geometric correction factor of the crack;

[0148] Specifically, step S230 includes:

[0149] For each component:

[0150] The following formula is used to calculate 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 to obtain the stress intensity factor of the crack of each component;

[0151] ;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.

[0152] For ease of understanding, the stress intensity factors of cracks in various components of the turbine are calculated based on the data in Table 7 above, as shown in Table 8 below:

[0153] Table 8 Stress intensity factors of cracks in various components of turbines

[0154]

[0155] S240: Obtaining a maximum stress intensity factor 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, as well as an equivalent crack size of each component, characteristic parameters of the crack, and a geometric correction factor;

[0156] 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.

[0157] S250, obtaining the crack propagation rate of each component 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;

[0158] Specifically, step S250 comprises:

[0159] For each component:

[0160] 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 by using the following formula to obtain the crack propagation rate of the component:

[0161] ; wherein, represents the crack propagation rate of the component, represents the first preset material constant of the crack of the component, represents the maximum stress intensity factor of the crack of the component, represents the minimum stress intensity factor of the crack of the component, represents the second preset material constant of the crack of the component.

[0162] 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 the crack of the component of the water turbine are exemplarily given as shown in Table 9 below:

[0163] Table 9 Stress intensity calculation parameters of the crack of the component of the water turbine

[0164]

[0165] S260, obtaining the failure probability of each component based on the expected life and the average life of each component.

[0166] Specifically, step S260 comprises:

[0167] For each component:

[0168] The expected life and the average life of the component are calculated by using the following formula to obtain the failure probability of the component:

[0169] ; wherein, represents the failure probability of the component, represents the expected life of the component, represents the average life of the component.

[0170] For ease of understanding, the failure probability of each component of the water turbine is calculated in combination with the data in Table 2 as shown in Table 10 below:

[0171] Table 10 Parameters for calculating the failure probability of turbine components

[0172]

[0173] S300, determining as a component to be evaluated a component having a weight distribution coefficient greater than a preset weight distribution coefficient, a stress intensity factor greater than a preset stress intensity factor, an expansion rate greater than a first preset expansion rate and less than a second preset expansion rate, and a failure probability greater than a preset failure probability;

[0174] For ease of understanding, the following examples are given with reference to the data in Tables 6, 8, 9, and 10:

[0175] Assume that the preset weight distribution coefficient is 0.12, the preset stress intensity factor is 300 MPa√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.

[0176] Guide vane 1 (crack): The weight distribution coefficient is 0.1374, which is greater than the preset 0.12; the stress intensity factor is 300.51 MPa√m, which is greater than the preset 300 MPa√m; the expansion rate is 2×10 -8 m / cycle, at the first default expansion rate of 10 -7 m / cycle and the second default expansion rate is 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 guide vane 1 (crack) is the component to be evaluated.

[0177] Guide vane 2: The weight distribution coefficient is 0.1540, which is greater than the preset value of 0.12. However, the stress intensity factor is 250.30 MPa√m, which is less than the preset value of 300 MPa√m. This does not meet the condition that the stress intensity factor is greater than the preset stress intensity factor. Therefore, guide vane 2 is not a component to be evaluated.

[0178] Guide vane 3: The weight distribution coefficient is 0.1112, which is less than the preset value of 0.12. This does not satisfy the condition that the weight distribution coefficient is greater than the preset weight distribution coefficient. Therefore, guide vane 3 is not a component to be evaluated.

[0179] Guide vane 4: The weight distribution coefficient is 0.1004, which is less than the preset weight distribution coefficient of 0.12. It does not meet the condition of "the weight distribution coefficient is greater than the preset weight distribution coefficient", so the guide vane 4 is not a component to be evaluated.

[0180] Guide vane 5: The weight distribution coefficient is 0.1167, which is less than the preset value of 0.12. This does not satisfy the condition that the weight distribution coefficient is greater than the preset weight distribution coefficient. Therefore, guide vane 5 is not a component to be evaluated.

[0181] Other component 1: The weight distribution coefficient is 0.1332, which is greater than the preset value of 0.12. However, the stress intensity factor is 270.32 MPa√m, which is less than the preset value of 300 MPa√m. This does not meet the condition that the stress intensity factor is greater than the preset stress intensity factor. Therefore, other component 1 is not a component to be evaluated.

[0182] Other component 2: The weight distribution coefficient is 0.1391, which is greater than the preset value of 0.12. However, the stress intensity factor is 260.28 MPa√m, which is less than the preset value of 300 MPa√m. This does not meet the condition that the stress intensity factor is greater than the preset stress intensity factor. Therefore, other component 2 is not a component to be evaluated.

[0183] 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". Therefore, other component 3 is not a component to be evaluated.

[0184] S400, obtaining multiple treatment measures and cost-benefit net present values ​​of the components to be evaluated;

[0185] The treatment measures for turbine components refer to a series of operating methods and means taken to ensure the normal operation, improve performance and extend service life of various turbine components in response to different conditions that may occur during operation.

[0186] The net present value (NPV) of the cost-benefit ratio of turbine components is an important indicator used to assess the economic feasibility of turbine component investment projects. It reflects the actual economic value of a project by considering its costs and benefits over its entire life cycle and discounting future cash flows to the present moment at a specific discount rate.

[0187] 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.

[0188] The following exemplary treatment measures for cracks in components of a hydraulic turbine are given as shown in Table 11 below:

[0189] Table 11 Treatment measures for cracks in turbine components

[0190]

[0191] In one embodiment, the cost-benefit net present value can be calculated using the following formula:

[0192] ;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.

[0193] For easier understanding, the following example is given in conjunction with Table 12:

[0194] Table 12 Parameters for calculating the net present value of cost-effectiveness of treatment measures

[0195]

[0196] S500, determining the risk level score of each treatment measure for each component to be evaluated, and determining the treatment measure with the minimum risk level score of each component to be evaluated and a net present value of cost-benefit greater than a preset threshold as the target treatment measure for each component to be evaluated;

[0197] In one embodiment, determining the risk level score of each treatment measure for each component to be evaluated includes:

[0198] For each component:

[0199] S510: Match each treatment measure for 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 for each treatment measure for the crack of the component to be evaluated; wherein the pre-constructed risk level score table is used to represent a mapping relationship between the treatment measure for the crack of the component to be evaluated and the severity score, the occurrence probability score, and the detection probability score;

[0200] Table 12 Pre-built risk level score table

[0201]

[0202] 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.

[0203] 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, to obtain a risk level score for each treatment measure for the crack of the component to be evaluated.

[0204] For ease of understanding, the following is an example of calculation based on Table 12 above:

[0205] Measure 1: 7*4*5=140; Measure 2: 8*3*4=96; Measure 3: 6*5*3=90.

[0206] Specifically, taking guide vane 1 (crack) as an example, its cost-benefit net present value is 649,200 yuan, which is greater than 0. Moreover, among the three treatment measures for guide vane 1 (crack), the risk level score of measure 3 is 90 points, which is the smallest score. Therefore, measure 3 is selected as the target treatment measure for guide vane 1 (crack).

[0207] 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.

[0208] In one or more of the above embodiments, the method for repairing and maintaining cracks in a turbine component further includes:

[0209] For each component:

[0210] 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;

[0211] 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 operating after a second preset operating time;

[0212] 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 operating after a third preset operating time;

[0213] 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;

[0214] 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 operating after a fourth preset operating time;

[0215] The first preset running time>the second preset running time>the third preset running time>the fourth preset running time.

[0216] For ease of understanding, the following examples are given with reference to the data in Tables 6, 7, 8, and 9:

[0217] 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.

[0218] (1) Guide vane 1 (crack):

[0219] Weight coefficient: 0.1374, which is greater than the preset weight distribution coefficient of 0.12.

[0220] Stress intensity factor: 300.51 MPa√m, which is greater than the preset stress intensity factor of 300 MPa√m.

[0221] Expansion rate: 2×10⁻ 8 m / cycle, at the first preset expansion rate of 10⁻ 7 m / cycle and the second preset expansion rate 10⁻ 9 m / cycle.

[0222] Failure probability: 0.55, which is greater than the preset failure probability of 0.5.

[0223] Handling method: Marked as a part to be evaluated.

[0224] (2) Guide vane 2:

[0225] Weight coefficient: 0.1540, which is greater than the preset weight distribution coefficient of 0.12.

[0226] Stress intensity factor: 250.30 MPa√m, which is less than the preset stress intensity factor of 300 MPa√m.

[0227] Treatment method: The control components stop operating after 72 hours of operation.

[0228] (3) Guide vane 3:

[0229] Weight coefficient: 0.1112, which is less than the preset weight distribution coefficient of 0.12.

[0230] Solution: Stop the control unit from running after one week.

[0231] (4) Guide vane 4:

[0232] Weight coefficient: 0.1004, which is smaller than the preset weight distribution coefficient of 0.12.

[0233] Solution: Stop the control unit from running after one week.

[0234] (5) Guide vane 5:

[0235] Weight coefficient: 0.1167, which is smaller than the preset weight distribution coefficient of 0.12.

[0236] Solution: Stop the control unit from running after one week.

[0237] (6) Other components 1:

[0238] Weight coefficient: 0.1332, which is greater than the preset weight distribution coefficient of 0.12.

[0239] Stress intensity factor: 270.32 MPa√m, which is less than the preset stress intensity factor of 300 MPa√m.

[0240] Treatment method: The control components stop operating after 72 hours of operation.

[0241] (7) Other components 2:

[0242] Weight coefficient: 0.1391, which is greater than the preset weight distribution coefficient of 0.12.

[0243] Stress intensity factor: 260.28 MPa√m, which is less than the preset stress intensity factor of 300 MPa√m.

[0244] Treatment method: The control components stop operating after 72 hours of operation.

[0245] (8) Other components 3:

[0246] Weight coefficient: 0.1080, which is smaller than the preset weight distribution coefficient of 0.12.

[0247] Solution: Stop the control unit from running after one week.

[0248] Beneficial effects of the present invention:

[0249] (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 single factors.

[0250] (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.

[0251] (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 cost-effectiveness net present value that meets the standard, take into account both risk and cost-effectiveness, and avoid excessive or insufficient treatment.

[0252] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0253] The above are merely 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 modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all 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: Obtain operating parameters, crack characteristic parameters, and far-field stresses of multiple turbine components. Operating parameters include multiple evaluation indicators, life expectancy, and average lifespan. Multiple evaluation indicators are standards for measuring component performance and reliability from different perspectives, including reliability, cost, maintenance requirements, impact on efficiency, material strength, durability, and flow control capabilities. 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 growth rate and the failure probability; Determine as a component to be evaluated 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; Obtain multiple treatment measures and cost-effectiveness net present values ​​of the components 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 net present value of cost-effectiveness greater than a preset threshold is the target treatment measure for each component to be evaluated; Sending 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; 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 growth 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; Obtaining a maximum stress intensity factor and a minimum stress intensity factor of the crack of each component based on a preset maximum far-field stress and a preset minimum far-field stress of the crack of each component, and based on an equivalent crack size, characteristic parameters of the crack, and a geometric correction factor of each component; Obtaining a crack growth 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; Based on the expected life and average life of each component, the failure probability of each component is obtained.

2. The method for operating and repairing cracks in turbine components according to claim 1, characterized in that: Different crack shapes have different characteristic parameters of cracks, including: If the crack is a circular crack, the characteristic parameters of the crack include the area of ​​the crack; If the crack 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 is a penetrating crack, the characteristic parameters of the crack include the width and depth of the crack; If 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 repairing cracks in turbine components according to claim 2, 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 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 set the preset constant As a geometric correction factor for circular cracks; ;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 crack is an elliptical crack, the major axis radius and 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 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 and the penetrating crack geometric correction factor; ;in, Indicates the depth of the equivalent through-crack of the component, represents the through-crack geometry correction factor, Indicates the depth of the crack in the component, Indicates the width of the crack in the component; If the crack is an edge crack, the following formula is used to calculate the pit depth and pit width of the crack of the component to obtain the depth of the equivalent plane crack and the plane crack geometric correction factor 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 in the component, Indicates the width of the crack in the component.

4. The method for operating and maintaining cracks in turbine components according to claim 1, 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 following formula is used to calculate 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 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.

5. The method for operating and maintaining cracks in turbine components according to claim 1, 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 growth 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 growth 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 the crack in the component, The minimum stress intensity factor for cracks in a component, A second predetermined material constant representing a crack in the component.

6. The method for operating and repairing cracks in turbine components according to claim 1, 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: Use the following formula to calculate the expected life and average life of the component to obtain the failure probability of the component; ;in, represents the failure probability of the component, Indicates the expected life of the component, Indicates the average life of a component.

7. The method for operating and repairing 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 for 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 for each treatment measure for the crack of the component to be evaluated; wherein the pre-constructed risk level score table is used to represent the mapping relationship between the treatment measure for 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.

8. The method for operating and repairing 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 operating after a second preset operating 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 operating after a third preset operating 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 operating after a fourth preset operating time; The first preset running time>the second preset running time>the third preset running time>the fourth preset running time.

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