Water delivery and supply pipeline safety risk evaluation method and system based on CFD-AHP

Abstract

The invention discloses a water conveying and supplying pipeline safety risk evaluation method and system based on CFD-AHP, and relates to the technical field of engineering safety and risk management. The computational fluid dynamics (CFD) is adopted for scene simulation, pipeline burst flow and impact force data under different working conditions are obtained, and a basis is provided for determination of pipeline failure key indexes. Based on a CFD simulation result, a multi-level security risk evaluation system is constructed, the multi-level security risk evaluation system comprises a target layer, a criterion layer and an evaluation layer, and the weight of each evaluation index is calculated through an analytic hierarchy process (AHP). And comprehensively analyzing the evaluation indexes by using a fuzzy comprehensive evaluation method to finally obtain a comprehensive evaluation result of the safety risk of the water delivery and supply pipeline. The CFD technology and the AHP method are combined, the scientific and systematic water conveying and supplying pipeline safety risk evaluation method is innovatively provided, the reliability and comprehensiveness of safety evaluation are improved, and a solid scientific basis is provided for safety management and maintenance of the pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering safety and risk management, and in particular to a water supply pipeline safety risk assessment method and system based on CFD-AHP. Background Art

[0002] With the acceleration of urbanization and the continuous growth of population, water supply pipelines, as an important part of urban infrastructure, are of vital importance to the normal operation of cities and the quality of life of residents. However, in the long-term operation of water supply pipelines, various failure events may occur, such as pipeline rupture and leakage, due to the complex influence of internal and external environments. These failure events will not only cause direct economic losses, but also have serious impacts on the surrounding environment and society. Therefore, how to scientifically and accurately evaluate the safety risks of water supply pipelines and then take effective prevention and control measures has become an important research topic in the field of engineering safety and risk management.

[0003] At present, the methods for safety assessment of water supply pipelines mainly include empirical judgment method, statistical analysis method and numerical simulation method. The empirical judgment method relies on the experience and intuition of experts. Although it can provide rapid assessment results in some cases, it is highly subjective, difficult to quantify, and has low accuracy and reliability. The statistical analysis method collects and analyzes a large amount of historical data to establish a failure probability model and a loss assessment model. It has certain scientificity and objectivity, but its applicability is limited in the absence of sufficient data. The development of computational fluid dynamics (CFD) technology has provided a powerful tool for the numerical simulation of water supply pipelines. CFD technology can simulate the flow of fluid inside the pipeline, obtain the flow rate and water flow impact force data of the pipeline under different working conditions, and thus accurately calculate the failure index of the pipeline. However, CFD technology can only simulate some indicators such as burst flow and impact force, and cannot make a comprehensive judgment on the safety risk of water supply pipelines. On the other hand, as a multi-criteria decision-making method, the Analytic Hierarchy Process (AHP) can perform hierarchical analysis on complex problems, and systematically evaluate the importance of each evaluation index by constructing a judgment matrix and calculating weights. However, some indexes based on burst flow and impact force lack reliable basis. Therefore, how to combine CFD technology with the AHP method, comprehensively utilize the advantages of numerical simulation and multi-criteria decision-making, and provide a scientific and accurate water supply pipeline safety risk assessment method is an urgent problem to be solved by technicians in this field. Summary of the invention

[0004] The purpose of the present invention is to propose a water supply pipeline safety risk assessment method and system based on CFD-AHP to improve the reliability and accuracy of water supply pipeline safety risk assessment and provide a scientific basis for pipeline safety management and maintenance.

[0005] According to a first aspect of an embodiment of the present disclosure, a water supply pipeline safety risk assessment method based on CFD-AHP is provided, comprising the following steps:

[0006] Obtain pipeline burst flow and water flow impact force data;

[0007] Construct a water supply pipeline safety risk assessment system, which includes the target layer, the criterion layer and the assessment layer;

[0008] Combine AHP to determine the weights of each indicator in the water supply pipeline safety risk assessment system;

[0009] Based on the weights of various indicators, a fuzzy comprehensive evaluation method is used to comprehensively evaluate the safety risks of water supply pipelines. The evaluation process includes determining the evaluation set, constructing a fuzzy evaluation matrix, and fuzzy comprehensive evaluation. The construction of the fuzzy evaluation matrix is ​​based on pipeline burst flow and water flow impact force data.

[0010] According to a second aspect of an embodiment of the present disclosure, a water supply pipeline safety risk assessment system based on CFD-AHP is provided, comprising:

[0011] Failure index acquisition module, which obtains pipeline burst flow and water flow impact force data;

[0012] The system establishment module builds a water supply pipeline safety risk assessment system, which includes the target layer, the criterion layer and the assessment layer;

[0013] The indicator weight acquisition module combines AHP to determine the weights of each indicator in the water supply pipeline safety risk assessment system;

[0014] The evaluation module uses a fuzzy comprehensive evaluation method based on the weights of each indicator to comprehensively evaluate the safety risks of water supply pipelines. The evaluation process includes determining the evaluation set, constructing a fuzzy evaluation matrix, and fuzzy comprehensive evaluation. The construction of the fuzzy evaluation matrix is ​​based on pipeline burst flow and water flow impact force data.

[0015] According to a third aspect of an embodiment of the present disclosure, an electronic device is provided, comprising a memory, a processor, and a computer program stored and running on the memory, wherein when the processor executes the program, the method for safety risk assessment of water supply pipelines based on CFD-AHP is implemented.

[0016] According to a fourth aspect of an embodiment of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the method for evaluating the safety risk of a water supply pipeline based on CFD-AHP is implemented.

[0017] Compared with the prior art, the above technical scheme adopted by the present invention has the following advantages: the present invention combines computational fluid dynamics (CFD) with the analytic hierarchy process (AHP) to propose a scientific and systematic water supply pipeline safety risk assessment method. Through CFD technology, detailed scenario simulation of the pipeline under different working conditions is carried out to accurately obtain pipeline burst flow and impact force data (and also provide alternative methods), and a multi-level risk assessment system is constructed in combination with the AHP method to comprehensively analyze the safety risks of the pipeline. This method effectively integrates qualitative and quantitative evaluation indicators and improves the reliability and accuracy of risk assessment. The fuzzy comprehensive evaluation technology performs a comprehensive calculation on the CFD simulation results and the weights determined by AHP, providing a scientific basis for the safety management and maintenance of the pipeline. Compared with traditional risk assessment methods, the present invention can more comprehensively identify potential risks, optimize the assessment process, and enhance the safety and operational stability of the pipeline system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0019] Figure 1 This is a flow chart of the water supply pipeline safety risk assessment method based on CFD-AHP. Specific implementation methods

[0021] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0022] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] It should be noted that the flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the methods and systems according to various embodiments of the present disclosure. It should be noted that each box in the flowchart or block diagram can represent a module, a program segment, or a part of a code, and the module, program segment, or a part of a code may include one or more executable instructions for implementing the logical functions specified in each embodiment. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the flowchart and / or block diagram, and the combination of boxes in the flowchart and / or block diagram can be implemented using a dedicated hardware-based system that performs a specified function or operation, or can be implemented using a combination of dedicated hardware and computer instructions.

[0025] Embodiment 1:

[0026] This embodiment provides a water supply pipeline safety risk assessment method based on CFD-AHP, comprising the following steps:

[0027] S1. Obtain pipeline burst flow and water flow impact force data;

[0028] Method 1: Use CFD technology to simulate the water supply pipeline and obtain pipeline burst flow and water flow impact force data under different working conditions. Specifically:

[0029] Establish model: For possible failure events of water supply and transmission pipelines, a three-dimensional pipeline model, soil-water interaction model and flooding process model are established based on the operating pressure, flow rate, pipeline length above the pressure elevation of the burst point, soil covering and other factors of the water supply pipeline;

[0030] Design scenarios: Design a variety of operating scenarios, including different flow rates, pressures, burst locations, etc., to simulate pipeline bursts under these scenarios;

[0031] Simulation operation: In CFD simulation, each scenario of the design is simulated to obtain the internal fluid flow of the pipeline under the corresponding scenario and the external behavior of the water flow after the burst;

[0032] Obtain failure indicators: Extract key parameters from the simulation results to obtain the burst flow rate of the pipeline under different working conditions and the water flow impact force data.

[0033] Method 2: In the absence of CFD calculation conditions, a simplified hydrodynamic method can be used to estimate the key variables. The burst water flow rate can be obtained by using the height difference Δz between the center point of the section of the pipe section at both ends of the burst and the center point of the section of the burst, the length of the two pipe sections L, the pipe diameter (D), etc., including:

[0034] First obtain the pipeline specific resistance:

[0035]

[0036] Where: D is the pipe diameter, in meters; S0 is the pipe specific resistance;

[0037] Then obtain the head loss along the way:

[0038] A) When water hammer is not considered:

[0039]

[0040] Where: h f is the head loss along the way, in m; Δz is the position head difference, in m; is the pressure head difference, in m;

[0041] B. Consider the water hammer:

[0042]

[0043] The water hammer wave velocity of the exposed steel pipe can be approximately taken as 1000m / s, and the water hammer pressure value is simplified to:

[0044] ΔH=100v

[0045] Where: ΔH is the water hammer pressure value, in m; v is the water flow velocity in the pipe, in m / s;

[0046] Finally, the burst flow is obtained:

[0047]

[0048] Where: Q is the burst water flow rate, unit is m 3 / s; L is the pipeline length, in meters.

[0049] A simplified method is used to obtain the water flow impact force, specifically:

[0050] The water flow impact force per unit length is:

[0051]

[0052] Where: F is the impact force of water flow per unit length on the pipe wall at a certain section in the pipe, in N; v is the flow velocity of water flow at a certain section in the pipe, in m / s; ρ is the density of water, in 1000 kg / m 3 ; S is the area of ​​a certain cross section in the pipeline, in m 2 ;

[0053] The impact force per unit area of ​​a unit length of water flow at a certain cross section is:

[0054] F i =v 2

[0055] Where: F i It is the horizontal or vertical impact force at a certain section in the pipeline, in kPa;

[0056] When the flow velocity v of a certain section of the pipe is unknown, the following formula is used for simplified estimation:

[0057]

[0058] Where: α is the impact coefficient, which is related to the opening direction of the burst flow, and can generally be taken as about 1.3; Q is the burst water flow, in m 3 / s; D is the pipe diameter, in m;

[0059] The comprehensive water flow impact force is obtained by using the horizontal water flow impact force and the vertical water flow impact force:

[0060]

[0061] S2. Construct a water supply pipeline safety risk assessment system, which includes a target layer, a criterion layer and an assessment layer;

[0062] Specifically, the target layer includes the safety risks of water supply pipelines; the criterion layer includes the severity level of pipeline failure consequences C1 and the failure probability level C2; the evaluation layer includes personnel deaths N1, direct economic losses N2, social impact N3, changes in foundation and external environment N4, operation and maintenance capabilities N5, dispatching and operation management N6 and investigation of the actual operation health status of the pipeline N7;

[0063] S3. Determine the weight of each indicator of the water supply pipeline safety risk assessment system in combination with AHP;

[0064] Construct a judgment matrix: Compare the indicators of the evaluation layer with those of the criterion layer, and obtain the importance of the evaluation indicators by comparing the quantitative values ​​between the indicators.

[0065] Specifically, according to the severity and possibility of failure of the indicators at the criterion level, the indicators at the evaluation level are compared pairwise, and the importance of the evaluation indicators is obtained by comparing the quantitative values ​​between the indicators (Table 1). The pairwise comparison results are used to construct a judgment matrix, which is an n×n matrix, where n is the number of indicators at the evaluation level. The matrix form is shown in Table 2, where element a ij Indicates the importance of the ith indicator relative to the jth indicator. For example, for the indicators "personnel deaths" and "direct economic losses" in the evaluation layer, if it is considered that "personnel deaths" are significantly more important than "direct economic losses", a can be given. 12 Assigned value is 5, then a 21 (i.e. “direct economic losses” relative to “fatalities”) is 1 / 5.

[0066] Table 1 Quantitative value regulations for comparison between indicators

[0067] Factor i is better than factor j Quantization value Equally important 1 Slightly important 3 Strong and important 5 Strongly important 7 Extremely important 9 The middle value of two adjacent judgments 2，4，6，8 reciprocal <![CDATA[a ij =1 / a ji ]]>

[0068] Table 2 Matrix form

[0069] N1 N2 N3 N4 N5 N6 N7 N1 1 <![CDATA[a 12 ]]> <![CDATA[a 13 ]]> <![CDATA[a 14 ]]> <![CDATA[a 15 ]]> <![CDATA[a 16 ]]> <![CDATA[a 17 ]]> N2 <![CDATA[a 21 ]]> 1 <![CDATA[a 23 ]]> <![CDATA[a 24 ]]> <![CDATA[a 25 ]]> <![CDATA[a 26 ]]> <![CDATA[a 27 ]]> N3 <![CDATA[a 31 ]]> <![CDATA[a 32 ]]> 1 <![CDATA[a 34 ]]> <![CDATA[a 35 ]]> <![CDATA[a 36 ]]> <![CDATA[a 37 ]]> N4 <![CDATA[a 41 ]]> <![CDATA[a 42 ]]> <![CDATA[a 43 ]]> 1 <![CDATA[a 45 ]]> <![CDATA[a 46 ]]> <![CDATA[a 47 ]]> N5 <![CDATA[a 51 ]]> <![CDATA[a 52 ]]> <![CDATA[a 53 ]]> <![CDATA[a 54 ]]> 1 <![CDATA[a 56 ]]> <![CDATA[a 57 ]]> N6 <![CDATA[a 61 ]]> <![CDATA[a 62 ]]> <![CDATA[a 63 ]]> <![CDATA[a 64 ]]> <![CDATA[a 65 ]]> 1 <![CDATA[a 67 ]]> N7 <![CDATA[a 71 ]]> <![CDATA[a 72 ]]> <![CDATA[a 73 ]]> <![CDATA[a 74 ]]> <![CDATA[a 75 ]]> <![CDATA[a 76 ]]> 1

[0070] Obtaining relative weights: First obtain the eigenvector and maximum eigenvalue of the judgment matrix, normalize the eigenvector, and obtain the weight of each indicator;

[0071] Specifically, each column of the judgment matrix is ​​normalized to obtain the sum of the elements of each column, and then each element is divided by the sum of the column to obtain the normalized judgment matrix, as follows:

[0072]

[0073] Sum each row of the normalized judgment matrix and divide it by n to get the weight vector w, forming the weight vector W:

[0074]

[0075] W=[w1...w i ]

[0076] Where: A i ' j is the i-th component of the normalized eigenvector, A ij is the i-th component of the original eigenvector, is the sum of all components of the eigenvector, w i is the weight of the ith indicator and satisfies W is a set of weight vectors.

[0077] Consistency test; according to the maximum eigenvalue λ of the judgment matrixmax , and get the consistency index CI and the average random consistency index RI:

[0078] Specifically, the weight vector w and eigenvalue λ of the judgment matrix A need to satisfy the following characteristic equation:

[0079] A·w=λ·w

[0080] Among them, λ is the eigenvalue, w is the corresponding weight vector, and the maximum eigenvalue λ is obtained according to the judgment matrix max .

[0081] Obtaining consistency indicators Where n is the dimension of the judgment matrix;

[0082] Get the consistency ratio Among them, RI is the random consistency index. The RI value is different for different n values. Table 3 shows the reference value of the random consistency index RI.

[0083] Table 3 Reference values ​​of random consistency index RI

[0084] n 1 2 3 4 5 6 7 8 9 10 RI 0 0 0.58 0.90 1.12 1.24 1.32 1.41 1.45 1.49

[0085] If the CR value is less than 0.1, the weight value is confirmed, otherwise the matrix is ​​re-adjusted.

[0086] S4. Based on the weights of various indicators, a fuzzy comprehensive evaluation method is used to comprehensively evaluate the safety risks of water supply pipelines. The evaluation process includes determining the evaluation set, constructing a fuzzy evaluation matrix, and fuzzy comprehensive evaluation. The construction of the fuzzy evaluation matrix is ​​based on the pipeline burst flow and water flow impact force data.

[0087] Determine the evaluation set: Determine four evaluation sets of "major risk, relatively large risk, general risk, and low risk" according to the water supply and transmission pipeline safety risk assessment level;

[0088] Table 4 Water supply pipeline safety risk assessment set

[0089]

[0090] Construct a fuzzy evaluation matrix: Based on the pipeline burst flow and water flow impact force data, determine the membership function of each evaluation index at different evaluation levels; standardize each evaluation index, and combine the membership values ​​of each evaluation index at different evaluation levels to form a fuzzy evaluation matrix; assuming there are m evaluation indicators and n evaluation levels, the form of the fuzzy evaluation matrix R is as follows:

[0091]

[0092] Among them, r mnIt represents the membership of the mth evaluation index on the nth evaluation level;

[0093] Specifically, taking the "personnel death" indicator as an example, the impact threshold is determined according to the evaluation level of the water supply pipeline safety risk. Assume that there are the following four evaluation levels and their corresponding impact thresholds:

[0094] Low risk: impact force ≤ v1

[0095] General risk: v1<impact force≤v2

[0096] Greater risk: v2<impact force≤v3

[0097] Major risk: Impact > v3

[0098] According to the impact force data, the membership function of the "personnel death" indicator at different risk levels is set. The triangular membership function is used to describe the membership:

[0099]

[0100] The impact force data in the CFD simulation results are standardized and converted into membership values. For a given impact force value v, its membership values ​​at the four evaluation levels of "low risk", "general risk", "relatively high risk" and "significant risk" are calculated respectively; the standardized membership values ​​are summarized to construct a fuzzy evaluation matrix. Each row of the fuzzy evaluation matrix corresponds to an evaluation index, and each column corresponds to an evaluation level. For example, for the "personnel death" index, its fuzzy evaluation matrix can be expressed as:

[0101] R 人员死亡 =[u 低风险 (v)u 一般风险 (v)u 较大风险 (v)u 重大风险 (v)]

[0102] Fuzzy comprehensive evaluation: Use the weights of the evaluation indicators and the fuzzy evaluation matrix to perform fuzzy comprehensive operations and obtain the comprehensive evaluation result vector B:

[0103] B=W·R

[0104] Among them, the comprehensive evaluation result vector B is in the following form:

[0105] B=[b1 b2…b n ]

[0106] According to the comprehensive evaluation result vector B, the safety risk level of the water supply pipeline is determined, and the maximum membership principle is adopted, that is, the risk level with the largest comprehensive evaluation value is selected as the final evaluation result.

[0107] Embodiment 2:

[0108] This embodiment provides a water supply pipeline safety risk assessment system based on CFD-AHP, including:

[0109] Failure index acquisition module, which obtains pipeline burst flow and water flow impact force data;

[0110] The system establishment module builds a water supply pipeline safety risk assessment system, which includes the target layer, the criterion layer and the assessment layer;

[0111] The indicator weight acquisition module combines AHP to determine the weights of each indicator in the water supply pipeline safety risk assessment system;

[0112] The evaluation module uses a fuzzy comprehensive evaluation method based on the weights of each indicator to comprehensively evaluate the safety risks of water supply pipelines. The evaluation process includes determining the evaluation set, constructing a fuzzy evaluation matrix, and fuzzy comprehensive evaluation. The construction of the fuzzy evaluation matrix is ​​based on pipeline burst flow and water flow impact force data.

[0113] Embodiment three:

[0114] An electronic device includes a memory, a processor, and a computer program stored and running on the memory, wherein the processor implements the above-mentioned water supply pipeline safety risk assessment method based on CFD-AHP when executing the program, including:

[0115] Obtain pipeline burst flow and water flow impact force data;

[0116] Construct a water supply pipeline safety risk assessment system, which includes the target layer, the criterion layer and the assessment layer;

[0117] Combine AHP to determine the weights of each indicator in the water supply pipeline safety risk assessment system;

[0118] Based on the weights of various indicators, a fuzzy comprehensive evaluation method is used to comprehensively evaluate the safety risks of water supply pipelines. The evaluation process includes determining the evaluation set, constructing a fuzzy evaluation matrix, and fuzzy comprehensive evaluation. The construction of the fuzzy evaluation matrix is ​​based on pipeline burst flow and water flow impact force data.

[0119] Embodiment 4:

[0120] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned water supply pipeline safety risk assessment method based on CFD-AHP, including:

[0121] Obtain pipeline burst flow and water flow impact force data;

[0122] Construct a water supply pipeline safety risk assessment system, which includes the target layer, the criterion layer and the assessment layer;

[0123] Combine AHP to determine the weights of each indicator in the water supply pipeline safety risk assessment system;

[0124] Based on the weights of various indicators, a fuzzy comprehensive evaluation method is used to comprehensively evaluate the safety risks of water supply pipelines. The evaluation process includes determining the evaluation set, constructing a fuzzy evaluation matrix, and fuzzy comprehensive evaluation. The construction of the fuzzy evaluation matrix is ​​based on pipeline burst flow and water flow impact force data.

[0125] Those skilled in the art should understand that the modules or steps of the present disclosure can be implemented by a general-purpose computer device, or alternatively, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. The present disclosure is not limited to any specific combination of hardware and software.

[0126] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0127] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A water supply pipeline safety risk assessment method based on CFD-AHP, characterized in that: The following steps are involved: Obtain pipeline burst flow and water flow impact force data; Construct a water supply pipeline safety risk assessment system, which includes the target layer, the criterion layer and the assessment layer; Combine AHP to determine the weights of each indicator in the water supply pipeline safety risk assessment system; Based on the weights of various indicators, a fuzzy comprehensive evaluation method is used to comprehensively evaluate the safety risks of water supply pipelines. The evaluation process includes determining the evaluation set, constructing a fuzzy evaluation matrix, and fuzzy comprehensive evaluation. The construction of the fuzzy evaluation matrix is ​​based on pipeline burst flow and water flow impact force data.

2. According to claim 1, a water supply pipeline safety risk assessment method based on CFD-AHP is characterized in that: Use CFD technology to simulate water supply pipelines and obtain pipeline burst flow and water flow impact force data under different working conditions, including: In view of the possible failure events of water supply pipelines, a three-dimensional pipeline model, soil-water interaction model and flooding process model are established based on the operating pressure, flow rate, pipeline length above the pressure elevation of the burst point and soil cover factors of the water supply pipeline; Design various scenarios with different flow rates, pressures, and burst locations to simulate pipeline bursts under these scenarios; In the CFD simulation, each scenario of the design is simulated to obtain the internal fluid flow of the pipeline and the external behavior of the water flow after the burst in the corresponding scenario; Extract key parameters from the simulation results to obtain the burst flow rate of the pipeline under different working conditions and the water flow impact force data.

3. According to the CFD-AHP-based water supply pipeline safety risk assessment method of claim 1, it is characterized in that: A simplified hydrodynamic method is used to estimate the key variables to obtain the pipeline burst flow, specifically: First obtain the pipeline specific resistance: Where: D is the pipe diameter, in meters; S0 is the pipe specific resistance; Then obtain the head loss along the way: A) When water hammer is not considered: Where: h f is the head loss along the way, in m; △z is the position head difference, in m; is the pressure head difference, in m; B. Consider the water hammer: Among them, the water hammer pressure value is simplified to: △H=100v Where: △H is the water hammer pressure value, unit is m; v is the water flow velocity in the pipe, unit is m / s; Finally, the burst flow is obtained: Where: Q is the burst water flow rate, unit is m 3 / s; L is the pipeline length, in meters.

4. The water supply pipeline safety risk assessment method based on CFD-AHP according to claim 1 is characterized in that: A simplified method is used to obtain the water flow impact force, specifically: The water flow impact force per unit length is: Where: F is the impact force of water flow per unit length on the pipe wall at a certain section in the pipe, in N; v is the flow velocity of water flow at a certain section in the pipe, in m / s; ρ is the density of water, in 1000 kg / m 3 ; S is the area of ​​a certain cross section in the pipeline, in m 2 ; The impact force per unit area of ​​a unit length of water flow at a certain cross section is: F i =v 2 Where: F i It is the horizontal or vertical impact force at a certain section in the pipeline, in kPa; When the flow velocity v of a certain section of the pipe is unknown, the following formula is used for simplified estimation: Where: α is the impact force coefficient, which is related to the opening direction of the burst flow; Q is the burst water flow, in m 3 / s; D is the pipe diameter, in m; The comprehensive water flow impact force is obtained by using the horizontal water flow impact force and the vertical water flow impact force:

5. The water supply pipeline safety risk assessment method based on CFD-AHP according to claim 1 is characterized in that: The target layer includes the safety risks of water supply pipelines; the criterion layer includes the severity level of pipeline failure consequences and the failure possibility level; the evaluation layer includes deaths of personnel, direct economic losses, social impacts, changes in infrastructure and external environment, operation and maintenance capabilities, scheduling and operation management, and investigation of the actual operating health status of the pipeline.

6. The water supply pipeline safety risk assessment method based on CFD-AHP according to claim 1 is characterized in that: Combined with AHP, the weights of various indicators in the water supply pipeline safety risk assessment system are determined, including: According to the indicators of the criterion layer, the indicators of the evaluation layer are compared, and the importance of the evaluation indicators is obtained by comparing the quantitative values ​​between the indicators; First, obtain the eigenvector and maximum eigenvalue of the judgment matrix, normalize the eigenvector, and obtain the weight of each indicator as follows: Where: A i ' j is the i-th component of the normalized eigenvector, A ij is the i-th component of the original eigenvector, is the sum of all components of the eigenvector, n is the number of evaluation indicators, and w i is the weight of the ith indicator, W is the set of weight vectors; According to the maximum eigenvalue λ of the judgment matrix max , and get the consistency index CI and the average random consistency index RI: Where: CR is the consistency ratio; λ max is the maximum eigenvalue obtained by eigenvalue decomposition; RI is the random consistency index. If the CR value is less than 0.1, the weight value is confirmed, otherwise the matrix is ​​re-adjusted.

7. The water supply pipeline safety risk assessment method based on CFD-AHP according to claim 1 is characterized in that: The fuzzy comprehensive evaluation method is used to comprehensively evaluate the safety risks of water supply pipelines, specifically: Determine the "major risk, relatively high risk, general risk, and low risk" evaluation set based on the water supply and transmission pipeline safety risk assessment level; Based on the pipeline burst flow and water flow impact force data, the membership function of each evaluation index at different evaluation levels is determined; each evaluation index is standardized, and the membership values ​​of each evaluation index at different evaluation levels are combined to form a fuzzy evaluation matrix; assuming that there are m evaluation indicators and n evaluation levels, the form of the fuzzy evaluation matrix R is as follows: Among them, r mn It represents the membership of the mth evaluation index on the nth evaluation level; Using the weights of the evaluation indicators and the fuzzy evaluation matrix, fuzzy comprehensive operations are performed to obtain the comprehensive evaluation result vector B: B=W·R.

8. A water supply pipeline safety risk assessment system based on CFD-AHP, characterized in that: include: Failure index acquisition module, which obtains pipeline burst flow and water flow impact force data; The system establishment module builds a water supply pipeline safety risk assessment system, which includes the target layer, the criterion layer and the assessment layer; The indicator weight acquisition module combines AHP to determine the weights of each indicator in the water supply pipeline safety risk assessment system; The evaluation module uses a fuzzy comprehensive evaluation method based on the weights of each indicator to comprehensively evaluate the safety risks of water supply pipelines. The evaluation process includes determining the evaluation set, constructing a fuzzy evaluation matrix, and fuzzy comprehensive evaluation. The construction of the fuzzy evaluation matrix is ​​based on pipeline burst flow and water flow impact force data.

9. An electronic device comprising a memory, a processor and a computer program stored and running on the memory, characterized in that: When the processor executes the program, the water supply pipeline safety risk assessment method based on CFD-AHP is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, the CFD-AHP-based water supply pipeline safety risk assessment method is implemented.

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