A method and device for determining the pressure state of a transient flow of a burst pipe in a pressurized pipe network, and a medium

Abstract

The present application relates to the technical field of municipal engineering, and discloses a method, device and medium for determining the pressure state of transient flow of a burst pipe in a pressurized pipe network, wherein the present application can convert the burst pipe event of the pressurized pipe network from the time domain to the frequency domain for analysis by calculating the Laplace frequency domain variable of the to-be-simulated burst pipe event, avoids the interpolation operation on time and space in the traditional method, reduces a large amount of calculation and memory burden, and the solutions on different frequencies are independent of each other, parallel computing can be adopted, and therefore the calculation efficiency is greatly improved. Further, by constructing the initial hydraulic boundary condition, the hydraulic state of each node when the burst pipe event occurs is accurately described, and then the steady-state hydraulic simulation before and after the burst pipe is respectively performed, and the accuracy of the simulation result is ensured. Finally, by constructing and solving the frequency domain equation of the transient flow of the pressurized pipe network, the accuracy of the obtained time sequence of the pressure change of the transient flow of the burst pipe in the pressurized pipe network is close to that of MOC, and the calculation efficiency is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of municipal engineering, and in particular to a method and device for determining the pressure state of transient flow of a burst pipe in a pressurized pipe network, and a medium. BACKGROUND

[0002] In the operation process of a pressurized pipe network system, once a burst pipe occurs, the internal pressure of the pipe will rapidly decrease, thereby causing a transient flow event. A high-frequency pressure sensing device deployed in the pipe network can monitor this transient flow event in real time and collect corresponding data. Further, by means of an inverse problem analysis method, the specific location of the burst pipe and the size of the burst pipe can be theoretically inferred by analyzing these monitoring data. However, the effective implementation of the inverse problem analysis method highly depends on an efficient and accurate transient flow mathematical model to achieve accurate simulation and calculation of the transient flow pressure.

[0003] At present, in the related field, the method of characteristics (MOC) is widely used due to its advantages of accurate results and easy programming. However, this method has a significant defect, that is, it performs poorly in terms of solving efficiency. On the one hand, when using MOC for calculation, the interpolation process of time and space will cause a large number of calculation tasks, and also has a high memory occupation requirement, which undoubtedly increases the calculation cost and system burden. On the other hand, the calculation process based on MOC can only be sequentially advanced in time grid, and cannot realize parallel computing, which to some extent limits the improvement of calculation efficiency.

[0004] In order to improve the calculation performance of transient flow pressure simulation, frequency domain analysis (FDA) becomes a feasible research direction. Under certain assumptions, the nonlinear part in the control equation is transformed into a linear form through certain mathematical transformation. After linearization, the linearized control equation is converted to the frequency domain by means of Fourier transform or Laplace transform, and then solved analytically in the frequency domain. Compared with the traditional method, frequency domain solving has obvious advantages: first, solving in the frequency domain does not require spatial interpolation operation, reducing the complex calculation steps; second, since the solutions at different frequencies are independent of each other, parallel computing is possible, which can fully utilize multi-core computing resources and greatly improve the calculation efficiency.

[0005] However, in the special scenario of burst pipe in a pressurized pipe network, the linearization assumption of the control equation relied on by the frequency domain analysis cannot be established. The failure of this assumption will cause a great error in the calculation of the burst pipe pressure by using FDA, seriously affecting the accuracy and reliability of the calculation results. SUMMARY

[0006] Therefore, the present application provides a method and device for determining the pressure state of a transient flow of a burst pipe in a pressurized pipe network and a medium, to solve the problems of low calculation accuracy and low calculation efficiency of the existing precise simulation calculation method for transient flow pressure.

[0007] In a first aspect, the present application provides a method for determining the pressure state of a transient flow of a burst pipe in a pressurized pipe network, which comprises:

[0008] The method comprises the following steps: obtaining a set of pipe network parameters of the pressurized pipe network system, a time period and a time interval of a to-be-simulated burst pipe event, the set of pipe network parameters comprising a plurality of pipe parameters, a plurality of constant flow node parameters, a plurality of constant pressure node parameters and a plurality of orifice outflow node parameters; calculating Laplace frequency domain variables of the to-be-simulated burst pipe event according to the time period and the time interval; constructing initial hydraulic boundary conditions of each node in the to-be-simulated burst pipe event according to the set of pipe network parameters; performing steady-state hydraulic simulation before and after the burst pipe respectively according to the set of pipe network parameters, to obtain a plurality of node steady-state vectors before the burst pipe, a plurality of first pipe segment steady-state vectors and a plurality of second pipe segment steady-state vectors after the burst pipe; constructing a pressurized pipe network transient flow frequency domain equation according to the set of pipe network parameters, the Laplace frequency domain variables, a plurality of hydraulic boundary conditions, the plurality of node steady-state vectors, the plurality of first pipe segment steady-state vectors and the plurality of second pipe segment steady-state vectors; solving the pressurized pipe network transient flow frequency domain equation and determining a pressurized pipe network burst pipe transient flow pressure change time sequence, the pressurized pipe network burst pipe transient flow pressure change time sequence being used to reflect the pressure change state of the pressurized pipe network burst pipe transient flow.

[0009] The method for determining the pressure state of a burst pipe transient flow of a pressurized pipe network provided by the application can accurately describe the structure, operating state and time range of a burst pipe event of a pressurized pipe network by obtaining a pipe network parameter set of the pressurized pipe network system, a time period and a time interval of a simulated burst pipe event, so that the simulation is more in line with the actual situation. Further, by calculating Laplace frequency domain variables of the simulated burst pipe event, the burst pipe event of the pressurized pipe network can be converted from the time domain to the frequency domain for analysis, avoiding the interpolation operation of time and space in the traditional method, reducing a large amount of calculation and memory burden, and the solutions at different frequencies are independent of each other, parallel computing can be used, thereby greatly improving the calculation efficiency. Further, the initial hydraulic boundary conditions of each node in the simulated burst pipe event are constructed according to the pipe network parameter set, the hydraulic state of each node when the burst pipe event occurs is accurately described, and then steady-state hydraulic simulation before and after the burst pipe is performed respectively, thereby ensuring the accuracy of the simulation results. Finally, the pressurized pipe network transient flow frequency domain equation is constructed by comprehensively utilizing the pipe network parameter set, the Laplace frequency domain variable, the hydraulic boundary condition and the steady-state vector, and the equation is solved, thereby maintaining the calculation accuracy equivalent to MOC, and then the pressurized pipe network burst pipe transient flow pressure change time sequence clearly reflecting the change state of the pressurized pipe network burst pipe transient flow pressure can be obtained, and the real-time simulation of the pressurized pipe network burst pipe transient pressure is realized. Therefore, by implementing the application, the accuracy of the obtained pressurized pipe network burst pipe transient flow pressure change time sequence approaches MOC while the calculation efficiency is greatly improved.

[0010] In an alternative embodiment, the Laplace frequency domain variable of the simulated burst pipe event is calculated according to the time period and the time interval, comprising:

[0011] The length of the pressure simulation result sequence of each pressurized pipe network node is calculated according to the time period and the time interval; the time sequence of the simulated burst pipe event is determined according to the length of the pressure simulation result sequence; and the Laplace frequency domain variable of the simulated burst pipe event is calculated according to the time sequence.

[0012] The method for determining the pressure state of the pipe burst transient flow of the pressurized pipe network provided by the application clearly defines the time range and time resolution of simulation through the time period and time interval, and then can determine the pressure simulation result of each node of the pressurized pipe network at each time point in the subsequent entire simulation process, so as to obtain a complete pressure simulation result sequence. Further, the time information related to the to-be-simulated pipe burst event is extracted from the pressure simulation result sequence of each node of the pressurized pipe network and forms a time sequence of the pipe burst event, which can focus more on the time process of the occurrence and development of the pipe burst event, removes the interference of other irrelevant information, and then can more clearly study the characteristics of the pipe burst event in the time dimension. Finally, the Laplace frequency domain variable is calculated through the time sequence, which can convert the pipe burst event of the pressurized pipe network from the time domain to the frequency domain for analysis, avoids the interpolation operation of time and space in the traditional method, reduces a large amount of calculation and memory burden, and the solutions at different frequencies are independent of each other, parallel computing can be adopted, so that the calculation efficiency is greatly improved.

[0013] In an optional implementation, steady-state hydraulic simulations before and after pipe burst are respectively performed according to the pipe network parameter set to obtain a plurality of node steady-state vectors before pipe burst, a plurality of first pipe segment steady-state vectors, and a plurality of second pipe segment steady-state vectors after pipe burst, including:

[0014] A first steady-state hydraulic model before pipe burst and a second steady-state hydraulic model after pipe burst are obtained; based on the pipe network parameter set, the first steady-state hydraulic model is solved to obtain a plurality of node steady-state vectors before pipe burst and a plurality of first pipe segment steady-state vectors; based on the pipe network parameter set, the second steady-state hydraulic model is solved to obtain a plurality of second pipe segment steady-state vectors after pipe burst.

[0015] The method for determining the pressure state of the pipe burst transient flow of the pressurized pipe network provided by the application can comprehensively and accurately describe the pressure, flow and other hydraulic parameters of each node of the pressurized pipe network before and after pipe burst and the flow and other information of each pipe segment by solving the first steady-state hydraulic model before pipe burst and the second steady-state hydraulic model after pipe burst, respectively, which provides an important basis for subsequent analysis of the influence of pipe burst on the hydraulic characteristics of the pipe network and helps to more accurately construct the transient flow frequency domain equation.

[0016] In an optional implementation, a transient flow frequency domain equation of the pressurized pipe network is constructed according to the pipe network parameter set, the Laplace frequency domain variable, a plurality of hydraulic boundary conditions, a plurality of node steady-state vectors, a plurality of first pipe segment steady-state vectors and a plurality of second pipe segment steady-state vectors, including:

[0017] constructing a pipe network association matrix according to the pipe network parameter set; constructing a pipe segment hyperbolic function vector and a pipe segment impedance vector according to the pipe network parameter set, the Laplace frequency domain variable, the plurality of node steady state vectors, the plurality of first pipe segment steady state vectors and the plurality of second pipe segment steady state vectors; and constructing a transient flow frequency domain equation of the pressure pipe network according to the pipe network association matrix, the plurality of hydraulic boundary conditions, the pipe segment hyperbolic function vector and the pipe segment impedance vector.

[0018] The method for determining the pressure state of the pipe network burst transient flow provided by the application can clearly reflect the connection relationship and topological structure between each pipe and node in the pipe network by constructing the pipe network association matrix according to the pipe network parameter set. Further, the pipe segment hyperbolic function vector and the pipe segment impedance vector are constructed, the physical parameters, frequency domain characteristics and steady state operation state of the pipe network are comprehensively considered, and then the hydraulic characteristics of the pipe segment in the pipe network burst transient process can be accurately reflected. Finally, the transient flow frequency domain equation of the pressure pipe network is constructed by combining the pipe network association matrix, the hydraulic boundary condition, the pipe segment hyperbolic function vector and the pipe segment impedance vector, the topological structure, hydraulic characteristics, boundary condition and frequency domain characteristics of the pipe network are comprehensively considered, and then the physical process of the pipe network burst transient flow can be accurately described, and an effective mathematical model is provided for solving the pressure change of the transient flow.

[0019] In an alternative embodiment, the transient flow frequency domain equation of the pressure pipe network is constructed according to the pipe network association matrix, the plurality of hydraulic boundary conditions, the pipe segment hyperbolic function vector and the pipe segment impedance vector, comprising:

[0020] constructing a decay index sequence; performing frequency domain conversion on the plurality of initial hydraulic boundary conditions by using the decay index sequence to obtain a plurality of target hydraulic boundary conditions; and constructing the transient flow frequency domain equation of the pressure pipe network according to the pipe network association matrix, the pipe segment hyperbolic function vector, the pipe segment impedance vector and the plurality of target hydraulic boundary conditions.

[0021] The method for determining the pressure state of the pipe network burst transient flow provided by the application can convert the time domain boundary condition into the expression form of the frequency domain by constructing the decay index sequence and performing frequency domain conversion on the plurality of initial hydraulic boundary conditions by using the sequence, and then the boundary condition can be matched with the frequency domain equation, and suitable boundary conditions are provided for solving the frequency domain equation. Further, by comprehensively considering the structure, hydraulic characteristics and boundary conditions of the pipe network and other factors, the transient flow frequency domain equation of the pressure pipe network constructed can more accurately simulate the actual situation of the pipe network burst transient flow, and the simulation accuracy and reliability are improved.

[0022] In an alternative embodiment, the transient flow frequency domain equation of the pressure pipe network is solved and the pressure change time sequence of the pipe network burst transient flow is determined, comprising:

[0023] The transient flow frequency domain equation of the pressurized pipe network is solved, and the transient flow frequency domain result of the pressurized pipe network is obtained.

[0024] The method for determining the pressure state of the pipe burst transient flow of the pressurized pipe network provided by the application is solved by the frequency domain, avoids the complex spatial interpolation and serial calculation in the traditional method, and improves the calculation efficiency. Further, the calculation result of the frequency domain is restored to the actual time scale, so that the time sequence of the pressure change of the pipe burst transient flow of the pressurized pipe network can directly reflect the change of the pressure of the pipe burst transient flow of the pressurized pipe network with time, and provides a direct reference basis for the actual operation and management of the pipe network.

[0025] In the second aspect, the application provides a device for determining the pressure state of the pipe burst transient flow of the pressurized pipe network, and the device comprises:

[0026] The acquisition module is configured to acquire a pipe network parameter set of the pressurized pipe network system, a time period of a to-be-simulated pipe burst event, and a time interval. The pipe network parameter set comprises a plurality of pipe parameters, a plurality of constant flow node parameters, a plurality of constant pressure node parameters, and a plurality of orifice outflow node parameters. The calculation module is configured to calculate Laplace frequency domain variables of the to-be-simulated pipe burst event according to the time period and the time interval. The first construction module is configured to construct initial hydraulic boundary conditions of each node in the to-be-simulated pipe burst event according to the pipe network parameter set. The simulation module is configured to respectively perform steady-state hydraulic simulation before and after the pipe burst according to the pipe network parameter set, to obtain a plurality of node steady-state vectors before the pipe burst, a plurality of first pipe segment steady-state vectors, and a plurality of second pipe segment steady-state vectors after the pipe burst. The second construction module is configured to construct a pressurized pipe network transient flow frequency domain equation according to the pipe network parameter set, the Laplace frequency domain variables, a plurality of hydraulic boundary conditions, the plurality of node steady-state vectors, the plurality of first pipe segment steady-state vectors, and the plurality of second pipe segment steady-state vectors. The solving module is configured to solve the pressurized pipe network transient flow frequency domain equation and determine a time sequence of the pressure change of the pipe burst transient flow of the pressurized pipe network. The time sequence of the pressure change of the pipe burst transient flow of the pressurized pipe network is used to reflect the pressure change state of the pipe burst transient flow of the pressurized pipe network.

[0027] In the third aspect, the application provides a computer device, which comprises a memory and a processor. The memory and the processor are communicatively connected to each other. The memory stores computer instructions. The processor executes the computer instructions, thereby executing the method for determining the pressure state of the pipe burst transient flow of the pressurized pipe network according to the first aspect or any of the corresponding embodiments.

[0028] In the fourth aspect, the application provides a computer readable storage medium, which stores computer instructions. The computer instructions are used to make a computer execute the method for determining the pressure state of the pipe burst transient flow of the pressurized pipe network according to the first aspect or any of the corresponding embodiments.

[0029] In a fifth aspect, the present application provides a computer program product comprising computer instructions for causing a computer to perform the burst pipe transient flow pressure state determination method of the first aspect above or any of its corresponding embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0031] Figure 1 is a flowchart of a burst pipe transient flow pressure state determination method according to an embodiment of the present application;

[0032] Figure 2 is a flowchart of another burst pipe transient flow pressure state determination method according to an embodiment of the present application;

[0033] Figure 3 is a flowchart of still another burst pipe transient flow pressure state determination method according to an embodiment of the present application;

[0034] Figure 4 is a pipe network topology diagram according to an embodiment of the present application;

[0035] Figure 5 is a structural block diagram of a burst pipe transient flow pressure state determination device according to an embodiment of the present application;

[0036] Figure 6 is a hardware structure schematic diagram of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0038] The embodiment of the present application provides a kind of pressure pipe network burst pipe transient flow pressure state determination method, by converting pressure pipe network burst pipe event from time domain to frequency domain for analysis, avoid the interpolation operation of time and space in traditional method, reduce a lot of calculation and memory burden, and the solution on different frequency is independent of each other, can adopt parallel computing, to greatly improve the calculation efficiency.

[0039] According to the embodiment of the present application, a pressure pipe network burst pipe transient flow pressure state determination method embodiment is provided, it should be noted that the steps shown in the flowchart of the drawing can be executed in a computer system, such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from here.

[0040] A pressure pipe network burst pipe transient flow pressure state determination method is provided in the present embodiment, which can be used in electronic devices, such as computers, mobile phones, tablets, etc. Figure 1 The flowchart of the pressure pipe network burst pipe transient flow pressure state determination method according to the embodiment of the present application is shown in Figure 1 The flowchart includes the following steps:

[0041] Step S101, obtain the pipe network parameter set of pressure pipe network system, the time period and time interval of the to-be-simulated burst pipe event.

[0042] Among them, the pipe network parameter set can include a plurality of pipe parameters, a plurality of constant flow node parameters, a plurality of constant pressure node parameters and a plurality of orifice outflow node parameters.

[0043] Specifically, a plurality of pipe parameters are used to describe the physical characteristics of each pipe in the pipe network. Assuming that there are ξ pipes in the pressure pipe network system, the pipes in the pipe network can be denoted as p, p = 1, 2, …, ξ. For pipe p, the plurality of pipe parameters can include pipe starting node, ending node, pipe length l p , diameter D p , Darcy-Weisbach friction factor f p , transient flow wave speed a p , pipe cross-sectional area A p .

[0044] Among them, the pipe starting node and the ending node are used to determine the position and connection relationship of the pipe in the pipe network; the pipe length l p and the diameter D p are used to affect the flow resistance and flow rate of water flow in the pipe; the Darcy-Weisbach friction factor f p is used to reflect the friction effect of the inner wall of the pipe on the water flow, which affects the energy loss; the transient flow wave speed a p is used to determine the speed of transient flow propagation; the pipe cross-sectional area Ap Flow rate calculation related, used to describe the pipe water capacity.

[0045] Further, the fixed flow node represents the node whose outflow is known in the steady state and transient process. Assuming that there are α fixed flow nodes in the pipe network, the fixed flow nodes in the pipe network can be denoted as i, i = 1, 2, …, α. For the fixed flow node i, the fixed flow node parameter records the outflow of the node in the steady state before pipe burst which reflects the outflow of each fixed flow node in the pipe network before pipe burst, and is an important basis for determining the initial hydraulic state of the pipe network, and is used to set boundary conditions and calculate related parameters in subsequent steady-state hydraulic simulation and frequency domain equation construction.

[0046] Further, the fixed pressure node represents the node whose pressure is known in the steady state and transient process. Assuming that there are β fixed pressure nodes in the pipe network, the fixed pressure nodes in the pipe network can be denoted as j, j = 1, 2, …, β. For the fixed pressure node j, the fixed pressure node parameter records the pressure of the node in the steady state before pipe burst which reflects the pressure state of each fixed pressure node in the pipe network before pipe burst, and is also used to set boundary conditions and calculate in subsequent steady-state hydraulic simulation and frequency domain equation construction.

[0047] Further, the orifice outflow node represents the node whose outflow and service head can be considered to satisfy the following relationship (1) of orifice outflow in the steady state and transient process:

[0048]

[0049] In the formula: φ represents the outflow of the orifice outflow node; ψ represents the service head of the orifice outflow node; θ represents the orifice outflow coefficient of the orifice outflow node. In particular, the node at which pipe burst occurs is an orifice outflow node, and the pipe burst event is simulated by a sudden increase in the orifice outflow coefficient of the orifice outflow node at the pipe burst.

[0050] Assuming that there are γ orifice outflow nodes in the pipe network, the orifice outflow nodes in the pipe network can be denoted as k, k = 1, 2, …, γ. For the orifice outflow node k, the orifice outflow node parameter records the orifice outflow coefficient of the node in the steady state before pipe burst which is used to describe the orifice outflow characteristics and set boundary conditions in pipe burst simulation and frequency domain equation construction.

[0051] Further, in order not to lose generality, the pipe burst node to be simulated is the orifice outflow node numbered 1, and is set as After the pipe burst is fully developed, the orifice outflow coefficient of the node is

[0052] Further, the pipe burst event to be simulated represents a manually set pipe burst scenario in the pressurized pipe network system, including information such as the location where the pipe burst occurs, the severity of the pipe burst (simulated by changes in the orifice outflow coefficient), and the like. In this embodiment, the node at which the pipe burst occurs is set as an orifice outflow node, and the pipe burst event is simulated by changing the orifice outflow coefficient of the node.

[0053] Further, the time period T of the pipe burst event to be simulated represents the duration set for simulating the pipe burst process, which is used to determine the time span of the entire simulation process, and affects the integrity and accuracy of the simulation results.

[0054] When simulating the pipe burst event, the time period T can be determined by comprehensively considering the complexity of the pressure change in the pipe network after the pipe burst and the pressure change process expected to be observed. If T is too short, the entire process of the pressure change after the pipe burst may not be captured completely; if T is too long, although more comprehensive information can be obtained, the calculation amount and calculation time will be increased. In this embodiment, the time period T is set as an integer multiple of the time interval Δt.

[0055] Further, the time interval Δt represents the time difference between adjacent two simulation time points in the simulation of the pipe burst process, which determines the time resolution of the simulation results, and affects the accuracy and calculation amount of the simulation data.

[0056] Step S102, according to the time period and the time interval, calculating the Laplace frequency domain variable of the pipe burst event to be simulated.

[0057] The Laplace frequency domain variable represents a complex number sequence, which can convert the pressurized pipe network pipe burst transient flow problem from the time domain to the frequency domain for analysis.

[0058] Specifically, by calculating the Laplace frequency domain variable of the pipe burst event to be simulated, the pipe burst event of the pressurized pipe network can be converted from the time domain to the frequency domain for analysis, avoiding the interpolation operation of time and space in the traditional method, reducing a large amount of calculation and memory burden, and the solutions at different frequencies are independent of each other, which can be calculated in parallel, thereby greatly improving the calculation efficiency.

[0059] Step S103, constructing initial hydraulic boundary conditions of each node in the pipe burst event to be simulated according to the pipe network parameter set.

[0060] The initial hydraulic boundary conditions of each node in the pipe burst event to be simulated can include initial hydraulic boundary conditions of the constant flow node, initial hydraulic boundary conditions of the constant pressure node, and initial hydraulic boundary conditions of the orifice outflow node.

[0061] First, the outflow of each constant flow node in the pipe burst event is set as a function of time t as shown in the following relationship (2):

[0062]

[0063] wherein: u i denotes the outflow of the fixed-flow node i at the steady state before the burst event. i,: (t) denotes the change of the outflow of the fixed-flow node i.

[0064] Further, the time series (vector) of the change of the outflow of the fixed-flow node i can be determined, as shown in the following relation (3):

[0065] u i,1 = [u i,n ,…,u i,N ](3)

[0066] wherein:

[0067] u i,n = u i (t n ) (4)

[0068] t n = (n-1)Δt (5)

[0069] Through the above process, the initial hydraulic boundary condition of the fixed-flow node reflecting the change of the outflow of the fixed-flow node with time during the burst event can be constructed.

[0070] Secondly, the head of each fixed-pressure node in the burst event is set as a function of time t as shown in the following relation (6):

[0071]

[0072] wherein: r j denotes the head of the fixed-pressure node j at the steady state before the burst event. j,: (t) denotes the change of the head of the fixed-pressure node j.

[0073] Further, the time series (vector) of the change of the head of the fixed-pressure node j can be determined, as shown in the following relation (7):

[0074] r j,1 = [r j,n ,…,r j,N ](7)

[0075] wherein: r j,n = r j (t n ).

[0076] Through the above process, the initial hydraulic boundary condition of the constant pressure node reflecting the change of the water head of the constant pressure node with time during the burst pipe process can be constructed.

[0077] Finally, the orifice outflow coefficient of each orifice outflow node in the burst pipe event is set as a function of time As shown in the following relationship (8):

[0078]

[0079] In the formula: θk represents the orifice outflow coefficient of the orifice outflow node k in the steady state before the burst pipe occurs; θk(t) represents the change amount of the orifice outflow coefficient of the orifice outflow node k. k (t) represents the change amount of the orifice outflow coefficient of the orifice outflow node k.

[0080] Further, the time sequence (vector) of the change amount of the orifice outflow coefficient of the orifice outflow node k can be determined, as shown in the following relationship (9):

[0081] θ k,: = [θ k,1 ,…,θ k,n ,…,θ k,N ](9)

[0082] Where: θ k,n = θ k (t n ).

[0083] Through the above process, the initial hydraulic boundary condition of the constant pressure node reflecting the change of the water head of the constant pressure node with time during the burst pipe process can be constructed.

[0084] In step S104, steady-state hydraulic simulation before and after the burst pipe is performed according to the pipe network parameter set, respectively, to obtain a plurality of node steady-state vectors before the burst pipe, a plurality of first pipe segment steady-state vectors, and a plurality of second pipe segment steady-state vectors after the burst pipe.

[0085] Wherein, the plurality of node steady-state vectors before the burst pipe represent the relevant parameter vectors of each node when the pipe network system is in a stable state before the burst pipe event occurs, which can include:

[0086] (1) The piezometer head vector of the steady state before the burst pipe of the constant flow node As shown in the following relationship (10):

[0087]

[0088] In the formula: Hpi represents the piezometer head of the steady state before the burst pipe of the i-th constant flow node.

[0089] (2) The outflow vector of the steady state before the burst pipe of the orifice outflow node The following relationship (11) is shown:

[0090]

[0091] In the formula: represents the steady-state outflow of the kth orifice outflow node before the pipe burst.

[0092] (3) The service head vector of the orifice outflow node before the pipe burst The following relationship (12) is shown:

[0093]

[0094] In the formula: represents the service head value of the kth orifice outflow node before the pipe burst.

[0095] (4) The orifice outflow coefficient vector of the orifice outflow node before the pipe burst The following relationship (13) is shown:

[0096]

[0097] Further, the pipe section is a part of the connection node, and therefore, the first pipe section steady-state vector represents the flow vector of each pipe section before the pipe burst event occurs The following relationship (14) is shown:

[0098]

[0099] In the formula: represents the steady-state flow of the pth pipe section before the pipe burst.

[0100] Further, the second pipe section steady-state vector represents the flow vector of each pipe section after the pipe burst event occurs The following relationship (15) is shown:

[0101]

[0102] In the formula: represents the flow of the pth pipe section after the pipe burst.

[0103] Step S105, according to the pipe network parameter set, the Laplace frequency domain variable, a plurality of hydraulic boundary conditions, a plurality of node steady-state vectors, a plurality of first pipe section steady-state vectors, and a plurality of second pipe section steady-state vectors, a transient flow frequency domain equation of the pressure pipe network is constructed.

[0104] The transient flow of the pressurized pipe network represents the fluctuation of pressure and flow rate of fluid in the pipe network due to sudden change of flow rate (such as pipe explosion, rapid opening and closing of valves, etc.); and the frequency domain equation of the transient flow of the pressurized pipe network represents a mathematical model for converting the transient flow problem of the pressurized pipe network from the time domain to the frequency domain for analysis.

[0105] Specifically, in the conventional time domain analysis method, the calculation amount is large and the memory occupation is high when dealing with such problems. In the embodiment, by comprehensively considering the parameter set of the pipe network, the Laplace frequency domain variable, the hydraulic boundary condition and the steady-state vector and constructing the frequency domain equation of the transient flow of the pressurized pipe network, the transient flow problem in the time domain can be converted to the frequency domain for solving through Laplace transform, thereby effectively reducing the subsequent calculation amount and memory burden, and parallel computing can be used, which greatly improves the calculation efficiency.

[0106] Step S106: solving the frequency domain equation of the transient flow of the pressurized pipe network and determining the time sequence of the pressure change of the pipe explosion transient flow of the pressurized pipe network.

[0107] Specifically, by solving the frequency domain equation of the transient flow of the pressurized pipe network, the calculation accuracy equivalent to MOC is maintained, and the time sequence of the pressure change of the pipe explosion transient flow of the pressurized pipe network which clearly reflects the change state of the pressure of the pipe explosion transient flow of the pressurized pipe network can be obtained, thereby realizing the real-time simulation of the transient pressure of the pipe explosion of the pressurized pipe network.

[0108] The method for determining the pressure state of the pipe network transient flow of the burst pipe provided in the embodiment can accurately describe the structure, operation state of the pipe network and time range of the burst pipe event by obtaining the pipe network parameter set of the pipe network system, time period and time interval of the simulated burst pipe event, so that the simulation is more in line with the actual situation. Further, the method can convert the burst pipe event of the pipe network from the time domain to the frequency domain for analysis by calculating the Laplace frequency domain variable of the simulated burst pipe event, avoids the interpolation operation on time and space in the traditional method, reduces a large amount of calculation and memory burden, and the solutions on different frequencies are independent of each other, parallel computing can be used, so that the calculation efficiency is greatly improved. Further, the initial hydraulic boundary condition of each node in the simulated burst pipe event is constructed according to the pipe network parameter set, the hydraulic state of each node when the burst pipe event occurs is accurately described, and then the steady-state hydraulic simulation before and after the burst pipe is performed respectively, so that the accuracy of the simulation result is ensured. Finally, the pipe network transient flow frequency domain equation of the pipe network is constructed by comprehensively using the pipe network parameter set, the Laplace frequency domain variable, the hydraulic boundary condition and the steady-state vector, and the pipe network transient flow frequency domain equation is solved, the calculation precision equivalent to MOC is maintained, and then the pipe network transient flow pressure change time sequence clearly reflecting the change state of the pipe network transient flow pressure of the burst pipe of the pipe network is obtained, and the real-time simulation of the burst pipe transient pressure of the pipe network is realized. Therefore, by implementing the method, the precision of the obtained pipe network transient flow pressure change time sequence of the burst pipe approaches MOC, and the calculation efficiency is greatly improved.

[0109] In the embodiment, a method for determining the pressure state of the pipe network transient flow of the burst pipe is provided, which can be used in electronic devices such as computers, mobile phones, tablet computers and the like. Figure 2 The method for determining the pressure state of the pipe network transient flow of the burst pipe according to the embodiment of the application is shown in the flowchart as Figure 2 The method for determining the pressure state of the pipe network transient flow of the burst pipe according to the embodiment of the application is shown in the flowchart as

[0110] In step S201, the pipe network parameter set of the pipe network system, the time period and the time interval of the simulated burst pipe event are obtained. For details, please refer to step S101 of the embodiment shown in Figure 1 The method for determining the pressure state of the pipe network transient flow of the burst pipe according to the embodiment of the application is shown in the flowchart as

[0111] In step S202, the Laplace frequency domain variable of the simulated burst pipe event is calculated according to the time period and the time interval.

[0112] Specifically, step S202 includes the following steps.

[0113] In step S2021, the length of the pressure simulation result sequence of each pipe network node is calculated according to the time period and the time interval.

[0114] Specifically, the pressure simulation result of each pipe network node in the pipe network is a sequence with a length of N. The length N is shown in the following relationship (16).

[0115]

[0116] Therefore, by the time period T and the time interval Δt, the length N of the pressure simulation result sequence of each pressurized pipe network node can be calculated.

[0117] In step S2022, the time sequence of the to-be-simulated pipe burst event is determined according to the length of the pressure simulation result sequence.

[0118] Wherein, the time sequence of the to-be-simulated pipe burst event represents the sequence (vector) of the time corresponding to the simulation result.

[0119] Specifically, after determining the length of the pressure simulation result sequence, the time sequence t of the to-be-simulated pipe burst event can be further determined, as shown in the following relation (17):

[0120] t = [t1, …, t n ,…,t N ](17)

[0121] Wherein, t N can be obtained by the above relation (5).

[0122] In step S2023, the Laplace frequency domain variable of the to-be-simulated pipe burst event is calculated according to the time sequence.

[0123] Wherein, the Laplace frequency domain variable ζ is also a sequence (vector) with a length of N.

[0124] Specifically, the Laplace frequency domain variable ζ of the to-be-simulated pipe burst event is as shown in the following relation (18):

[0125] ζ = [ζ1, …, ζ m ,…,ζ N ](18)

[0126] Wherein, ζ m is as shown in the following relation (19):

[0127]

[0128] In the formula: denotes the imaginary unit σ represents the convergence index of the Laplace transform, which can be selected according to the following relation (20):

[0129]

[0130] The Laplace frequency domain variable is calculated through time series, which can convert the pipe burst event of the pressure pipe network from time domain to frequency domain for analysis, avoids the interpolation operation of time and space in the traditional method, reduces a large amount of calculation and memory burden, and the solutions on different frequencies are independent of each other, parallel computing can be used, so that the calculation efficiency is greatly improved.

[0131] In step S203, initial hydraulic boundary conditions of each node in the to-be-simulated pipe burst event are constructed according to the pipe network parameter set. For details, please refer to Figure 1 In step S103 of the embodiment shown, no further description is given here.

[0132] In step S204, steady-state hydraulic simulation is performed before and after the pipe burst according to the pipe network parameter set, to obtain a plurality of node steady-state vectors before the pipe burst, a plurality of first pipe segment steady-state vectors, and a plurality of second pipe segment steady-state vectors after the pipe burst.

[0133] Specifically, the above step S204 includes:

[0134] In step S2041, a first steady-state hydraulic model before the pipe burst and a second steady-state hydraulic model after the pipe burst are obtained.

[0135] The first steady-state hydraulic model comprehensively considers the flow of fluid in the pipe network, energy loss, and the interaction relationship of each node and pipe segment, and can present the hydraulic characteristics of the pipe network in a stable state in the form of a mathematical equation; the second steady-state hydraulic model can reflect the influence of the pipe burst on the fluid flow, pressure distribution, and hydraulic parameters of each node and pipe segment in the pipe network.

[0136] Specifically, according to various parameters of the pipe network, such as pipeline parameters (including starting node, ending node, length, diameter, friction coefficient, transient flow wave speed, cross-sectional area, etc.), constant flow node parameters (outflow of the node in the steady state before the pipe burst), constant pressure node parameters (water head of the pressure measuring point in the steady state before the pipe burst), orifice outflow node parameters (orifice outflow coefficient of the node in the steady state before the pipe burst), etc., a professional hydraulic analysis software, such as EPANET, WaterGEMs, etc., can be used to establish a first steady-state hydraulic model that can describe the stable operation state of the pipe network before the pipe burst.

[0137] Further, after setting the position of the pipe burst and related parameters (such as setting the pipe burst position as an orifice outflow node and changing the orifice outflow coefficient to simulate the severity of the pipe burst), the same or similar hydraulic analysis software is used to establish a second steady-state hydraulic model that can reflect the state of the pipe network after the pipe burst, when the pipe network system reaches a certain stable state again, according to the pipe network parameter set and the change of the hydraulic state of the pipe network after the pipe burst.

[0138] Step S2042, based on the pipe network parameter set, the first steady-state hydraulic model is solved to obtain a plurality of node steady-state vectors and a plurality of first pipe segment steady-state vectors before the pipe burst.

[0139] Specifically, the pipe network parameter set is input into the first steady-state hydraulic model for solving, and a plurality of node steady-state vectors shown in the above relational expressions (10) to (13) and a first pipe segment steady-state vector of each pipe segment shown in the relational expression (14) can be obtained.

[0140] Step S2043, based on the pipe network parameter set, the second steady-state hydraulic model is solved to obtain a plurality of second pipe segment steady-state vectors after the pipe burst.

[0141] Specifically, the pipe network parameter set is input into the second steady-state hydraulic model for solving, and a second pipe segment steady-state vector of each pipe segment shown in the above relational expression (15) can be obtained.

[0142] Step S205, according to the pipe network parameter set, the Laplace frequency domain variable, a plurality of hydraulic boundary conditions, a plurality of node steady-state vectors, a plurality of first pipe segment steady-state vectors and a plurality of second pipe segment steady-state vectors, a transient flow frequency domain equation of the pressure pipe network is constructed. For details, please refer to step S105 of the embodiment shown in Figure 1 Step S106 of the embodiment shown in

[0143] Step S206, the transient flow frequency domain equation of the pressure pipe network is solved and a pipe burst transient flow pressure change time sequence of the pressure pipe network is determined. For details, please refer to step S106 of the embodiment shown in Figure 1 Step S106 of the embodiment shown in

[0144] The pressure state determination method for pipe burst transient flow of the pressure pipe network provided in the embodiment clearly defines the time range and time resolution of simulation through the time period and time interval, and then can determine the pressure simulation result of each node of the pressure pipe network at each time point in the subsequent entire simulation process, so as to obtain a complete pressure simulation result sequence. Further, the time information related to the to-be-simulated pipe burst event is extracted from the pressure simulation result sequence of each node of the pressure pipe network and forms a time sequence of the pipe burst event, which can focus more on the time process of the occurrence and development of the pipe burst event, removes the interference of other irrelevant information, and then can more clearly study the characteristics of the pipe burst event in the time dimension. Finally, the Laplace frequency domain variable is calculated through the time sequence, which can convert the pipe burst event of the pressure pipe network from the time domain to the frequency domain for analysis, avoids the interpolation operation of time and space in the traditional method, reduces a large amount of calculation and memory burden, and the solutions on different frequencies are independent of each other, parallel computing can be adopted, so that the calculation efficiency is greatly improved. Further, the first steady-state hydraulic model before the pipe burst and the second steady-state hydraulic model after the pipe burst are solved respectively, which can comprehensively and accurately describe the pressure, flow and other hydraulic parameters of each node of the pressure pipe network and the flow and other information of each pipe section before and after the pipe burst, provides an important basis for analyzing the influence of the pipe burst on the hydraulic characteristics of the pipe network, and helps to more accurately construct the transient flow frequency domain equation.

[0145] In the embodiment, a pressure pipe network pipe burst transient flow pressure state determination method is provided, which can be used for electronic devices such as computers, mobile phones, tablet computers and the like. Figure 3 The flowchart of the pressure pipe network pipe burst transient flow pressure state determination method according to the embodiment of the application is shown in Figure 3 The flowchart includes the following steps:

[0146] In step S301, the pipe network parameter set of the pressure pipe network system, the time period and the time interval of the to-be-simulated pipe burst event are obtained. For details, refer to step S101 of the embodiment shown in Figure 1 The details are not repeated here.

[0147] In step S302, the Laplace frequency domain variable of the to-be-simulated pipe burst event is calculated according to the time period and the time interval. For details, refer to step S202 of the embodiment shown in Figure 2 The details are not repeated here.

[0148] In step S303, the initial hydraulic boundary condition of each node in the to-be-simulated pipe burst event is constructed according to the pipe network parameter set. For details, refer to step S103 of the embodiment shown in Figure 1 The details are not repeated here.

[0149] Step S304, according to the pipe network parameter set, respectively, before and after the pipe explosion steady-state hydraulic simulation, get a plurality of node steady-state vector before the pipe explosion, a plurality of first pipe segment steady-state vector and a plurality of second pipe segment steady-state vector after the pipe explosion. Details, please refer to Figure 2 Step S204 of the embodiment shown, not here again.

[0150] Step S305, according to the pipe network parameter set, Laplace frequency domain variable, a plurality of hydraulic boundary conditions, a plurality of node steady-state vector, a plurality of first pipe segment steady-state vector and a plurality of second pipe segment steady-state vector, construct the transient flow frequency domain equation of the pressure pipe network.

[0151] Specifically, the above step S305 includes:

[0152] Step S3051, according to the pipe network parameter set, construct the pipe network association matrix.

[0153] Specifically, for pipe p and constant flow node i, the following size ξ × α association matrix M 1D And M 1U The elements in the matrix are shown in the following relationship (21) and (22) respectively:

[0154]

[0155] Further, for pipe p and constant pressure node j, the following size ξ × β association matrix M 2D And M 2U The elements in the matrix are shown in the following relationship (23) and (24) respectively:

[0156]

[0157] Further, for pipe p and orifice outflow node k, the following size ξ × γ association matrix M 3D And M 3U The elements in the matrix are shown in the following relationship (25) and (26) respectively:

[0158]

[0159] The pipe network association matrix is constructed by the pipe network parameter set, which can clearly reflect the connection relationship and topological structure between each pipe and node in the pipe network.

[0160] Step S3052, according to the pipe network parameter set, Laplace frequency domain variable, a plurality of node steady-state vector, a plurality of first pipe segment steady-state vector and a plurality of second pipe segment steady-state vector, construct the pipe segment hyperbolic function vector and pipe segment impedance vector.

[0161] Specifically, the hyperbolic function vector c :,mThe following relationship (27) is shown:

[0162] c :,m = [cosh(μ 1,m l1),…cosh(μ p,m l p ),…,cosh(μ ξ,m l ξ )] T (27)

[0163] In the formula: μ p,m represents the transfer constant corresponding to the mth frequency domain variable of the pipeline p, as shown in the following relationship (28):

[0164]

[0165] In the formula: R p,m represents the friction term corresponding to the mth frequency domain variable of the pipeline p, as shown in the following relationship (29):

[0166]

[0167] In the formula: Δq p represents the flow difference between the steady state after the pipe explosion and the steady state before the pipe explosion of the pipeline p, as shown in the following relationship (30):

[0168]

[0169] Similarly, the hyperbolic function vector s :,m corresponding to the mth frequency domain variable is shown in the following relationship (31):

[0170] s :,m = [sinh(μ 1,m l1),…sinh(μ p,m l p ),…,sinh(μ ξ,m l ξ ] T (31)

[0171] Further, the impedance vector z :,m corresponding to the mth frequency domain variable is shown in the following relationship (32):

[0172] z :,m = [z 1,m ,…,z p,m ,…,z ξ,m ] T (32)

[0173] In the formula: z p,m represents the impedance corresponding to the mth frequency domain variable of the pipeline p, as shown in the following relationship (33):

[0174]

[0175] wherein g represents the acceleration of gravity.

[0176] Further, substituting the known pipe network parameter set, the Laplace frequency domain variable, the plurality of node steady state vectors, the plurality of first pipe segment steady state vectors and the plurality of second pipe segment steady state vectors into the above corresponding relationship respectively, the corresponding pipe segment hyperbolic function vector and the pipe segment impedance vector can be constructed.

[0177] In step S3053, the transient flow frequency domain equation of the pressurized pipe network is constructed according to the pipe network association matrix, the plurality of hydraulic boundary conditions, the pipe segment hyperbolic function vector and the pipe segment impedance vector.

[0178] Specifically, by comprehensively considering the topological structure, hydraulic characteristics, boundary conditions and frequency domain characteristics of the pipe network, the corresponding transient flow frequency domain equation of the pressurized pipe network is constructed, which can accurately describe the physical process of the pipe burst transient flow of the pressurized pipe network and provide an effective mathematical model for solving the transient flow pressure change.

[0179] In some optional embodiments, the above step S3053 comprises:

[0180] In step a1, an attenuation index sequence is constructed.

[0181] In step a2, the plurality of initial hydraulic boundary conditions are frequency domain converted by using the attenuation index sequence to obtain a plurality of target hydraulic boundary conditions.

[0182] In step a3, the transient flow frequency domain equation of the pressurized pipe network is constructed according to the pipe network association matrix, the pipe segment hyperbolic function vector, the pipe segment impedance vector and the plurality of target hydraulic boundary conditions.

[0183] Specifically, the attenuation index sequence is constructed as shown in the following relationship (34):

[0184] y = [y1, …, y n , y N ](34)

[0185] wherein y n is as shown in the following relationship (35):

[0186] y n = exp(-σ·t n ) (35)

[0187] wherein exp represents an exponential function.

[0188] Further, the multiplication of vectors according to corresponding elements is represented by and the hydraulic boundary condition u i,:Transforming into the frequency domain, the following relationship (36) is shown:

[0189]

[0190] Wherein: represents the boundary condition vector of the fixed-flow node i in the frequency domain, i.e., the target hydraulic boundary condition, as shown in the following relationship (37):

[0191]

[0192] In the formula: represents the outflow-related value of the fixed-flow node i corresponding to the mth frequency domain variable in the frequency domain.

[0193] Further, the boundary condition r j,: Transforming into the frequency domain, the following relationship (38) is shown:

[0194]

[0195] In the formula: represents the boundary condition vector of the fixed-pressure node j in the frequency domain, i.e., the target hydraulic boundary condition, as shown in the following relationship (38):

[0196]

[0197] In the formula: represents the head-related value of the fixed-pressure node j corresponding to the mth frequency domain variable in the frequency domain.

[0198] Further, the boundary condition θ k,: Transforming into the frequency domain, the following relationship (40) is shown:

[0199]

[0200] In the formula: represents the boundary condition vector of the orifice outflow node k in the frequency domain, i.e., the target hydraulic boundary condition, as shown in the following relationship (41):

[0201]

[0202] In the formula: represents the orifice outflow coefficient-related value of the orifice outflow node k corresponding to the mth frequency domain variable in the frequency domain.

[0203] Finally, the corresponding transient flow frequency domain equation of the pressure pipe network can be constructed, as shown in the following relationship (42):

[0204] A m x m = b m (42)

[0205] where A m is shown in the following relation (43):

[0206]

[0207] where Φ, Ψ, C m , S m and Z m are diagonal matrices, respectively shown in the following relations (44) to (48):

[0208]

[0209]

[0210] C m = diag(c :,m ) (46)

[0211] S m = diag(s :,m ) (47)

[0212] Z m = diag(z :,m ) (48)

[0213] Further, Λ m is also a diagonal matrix, which is the correction coefficient corresponding to the mth frequency domain variable of each orifice outflow node, shown in the following relation (49):

[0214] Λ m = diag(λ :,m ) (49)

[0215] where λ :,m = [λ 1,m ,…, λ k,m ,…, λ γ,m ] T .

[0216] Further, λ k,m is shown in the following relation (50):

[0217]

[0218] Further, b m is shown in the following relation (51):

[0219]

[0220] where:

[0221]

[0222] Further, Θ is a diagonal matrix, as shown in the following relation (55):

[0223]

[0224] Further, x m is a solution vector, as shown in the following relation (56):

[0225]

[0226] wherein:

[0227]

[0228] In the formula: represents the change in downstream flow of the pipeline p corresponding to the mth frequency domain variable; represents the change in upstream flow of the pipeline p corresponding to the mth frequency domain variable; represents the change in head of the pipeline p corresponding to the mth frequency domain variable; represents the change in service head of the pipeline p corresponding to the mth frequency domain variable.

[0229] Step S306, solving the frequency domain equation of the transient flow of the pressurized pipe network and determining the pressure change time sequence of the pipe burst transient flow of the pressurized pipe network.

[0230] Specifically, the above step S306 includes:

[0231] Step S3061, solving the frequency domain equation of the transient flow of the pressurized pipe network to obtain the frequency domain result of the transient flow of the pressurized pipe network.

[0232] Specifically, by solving the frequency domain equation of the transient flow of the pressurized pipe network, the corresponding frequency domain result x m of the transient flow of the pressurized pipe network can be obtained.

[0233] Step S3062, time domain conversion of the frequency domain structure of the transient flow of the pressurized pipe network to obtain the pressure change time sequence of the pipe burst transient flow of the pressurized pipe network.

[0234] Specifically, the frequency domain result is converted back to the time domain to obtain the pressure result at each node in the pipe network, as shown in the following relations (61) to (62):

[0235]

[0236] Further, the pressure of each node is as shown in the following relations (63) to (64):

[0237]

[0238] wherein, denotes a pressure variation time sequence of the sought constant-flow node i; denotes a pressure variation time sequence of the sought orifice outflow node k.

[0239] The method for determining the pressure state of the burst pipe transient flow of the pressurized pipe network provided by the embodiment can clearly reflect the connection relationship and topological structure between each pipe and node in the pipe network by constructing a pipe network association matrix based on a set of pipe network parameters. Further, by constructing a pipe section hyperbolic function vector and a pipe section impedance vector, the physical parameters, frequency domain characteristics and steady state operating conditions of the pipe network are comprehensively considered, and thus the hydraulic characteristics of the pipe section in the burst pipe transient process can be accurately reflected. Further, by constructing a decay index sequence and using the sequence to convert multiple initial hydraulic boundary conditions in the frequency domain, the boundary conditions in the time domain can be converted into an expression form in the frequency domain, and thus the boundary conditions can be matched with the frequency domain equation, thereby providing suitable boundary conditions for solving the frequency domain equation. Further, by comprehensively considering the structure, hydraulic characteristics and boundary conditions of the pipe network and other factors, the frequency domain equation of the burst pipe transient flow of the pressurized pipe network constructed can more accurately simulate the actual situation of the burst pipe transient flow of the pressurized pipe network, and the simulation accuracy and reliability are improved. Further, by solving in the frequency domain, the complex spatial interpolation and serial calculation in the traditional method are avoided, and the calculation efficiency is improved. Further, the calculation results in the frequency domain are restored to the actual time scale, so that the pressure variation time sequence of the burst pipe transient flow of the pressurized pipe network can intuitively reflect the change of the pressure of the burst pipe transient flow of the pressurized pipe network with time, thereby providing a direct reference basis for the actual operation and management of the pipe network.

[0240] In an example, a numerical experiment using a medium-sized real pipe network is used to verify the method for determining the pressure state of the burst pipe transient flow of the pressurized pipe network provided by the embodiment.

[0241] Specifically, the pipe network is located in a town in an eastern coastal area, and the total length of the pipe network is 45.83 km, and the topological structure is as shown in Figure 4 The pipe network contains a total of 126 outflow nodes, 149 pipes, and 1 constant-pressure node. The length of the pipe is between 24 m and 1238.4 m, and the diameter is between 100 mm and 400 mm. The Darcy-Weisbach friction factor of the pipe ranges from 0.0142 to 0.0554. Before the pipe burst occurs, the total outflow of the nodes of the entire pipe network is 145 L / s, and the outflow of each node is between 0 L / s and 4.35 L / s.

[0242] It is assumed that the pipe burst occurs at node J 124, and the pipe burst flow is 4.1 L / s, as shown in Figure 4The middle triangle is shown. Including the burst pipe node itself, a total of 8 nodes in the pipe network are selected as example nodes to show the effectiveness of the fast calculation method of the burst pipe pressure state. When selecting example nodes, they are evenly distributed in the pipe network and can represent the conditions of each part of the pipe network (for example Figure 4 The middle circle is shown). By using the traditional MOC and the fast calculation method of the burst pipe pressure state proposed in this paper, the time series of the burst pipe pressure of the example nodes are calculated respectively, and the two are compared. The total time length of the simulated pipe pressure change is 30s, and the simulation time interval is 0.004s.

[0243] It can be seen from the comparison that the results of the burst pipe transient flow pressure state determination method provided in this embodiment are highly consistent with the traditional MOC results, but the calculation efficiency of the method proposed in this paper is greatly improved, and the calculation time can be reduced by an order of magnitude.

[0244] In this embodiment, a burst pipe transient flow pressure state determination device for a pressurized pipe network is also provided, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be described again. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware is also possible and is conceived.

[0245] This embodiment provides a burst pipe transient flow pressure state determination device for a pressurized pipe network, as shown in Figure 5 The device comprises:

[0246] The acquisition module 501 is configured to acquire a pipe network parameter set of the pressurized pipe network system, a time period of a to-be-simulated burst pipe event, and a time interval. The pipe network parameter set comprises a plurality of pipe parameters, a plurality of constant flow node parameters, a plurality of constant pressure node parameters, and a plurality of orifice outflow node parameters.

[0247] The calculation module 502 is configured to calculate Laplace frequency domain variables of the to-be-simulated burst pipe event according to the time period and the time interval.

[0248] The first construction module 503 is configured to construct initial hydraulic boundary conditions of each node in the to-be-simulated burst pipe event according to the pipe network parameter set.

[0249] The simulation module 504 is configured to perform steady-state hydraulic simulation before and after the burst pipe respectively according to the pipe network parameter set, to obtain a plurality of node steady-state vectors before the burst pipe, a plurality of first pipe segment steady-state vectors, and a plurality of second pipe segment steady-state vectors after the burst pipe.

[0250] The second construction module 505 is configured to construct the frequency domain equation of transient flow of the pressurized pipe network according to the pipe network parameter set, the Laplace frequency domain variable, the plurality of hydraulic boundary conditions, the plurality of node steady-state vectors, the plurality of first pipe segment steady-state vectors and the plurality of second pipe segment steady-state vectors.

[0251] The solving module 506 is configured to solve the frequency domain equation of transient flow of the pressurized pipe network and determine a time series of pressure change of the pipe burst transient flow of the pressurized pipe network, the time series of pressure change of the pipe burst transient flow of the pressurized pipe network reflecting a state of pressure change of the pipe burst transient flow of the pressurized pipe network.

[0252] In some optional embodiments, the calculation module 502 includes:

[0253] The first calculation sub-module is configured to calculate a length of the pressure simulation result sequence of each node of the pressurized pipe network according to the time period and the time interval.

[0254] The determination sub-module is configured to determine a time sequence of the to-be-simulated pipe burst event according to the length of the pressure simulation result sequence.

[0255] The second calculation sub-module is configured to calculate the Laplace frequency domain variable of the to-be-simulated pipe burst event according to the time sequence.

[0256] In some optional embodiments, the simulation module 504 includes:

[0257] The acquisition sub-module is configured to acquire a first steady-state hydraulic model before pipe burst and a second steady-state hydraulic model after pipe burst.

[0258] The first solving sub-module is configured to solve the first steady-state hydraulic model based on the pipe network parameter set to obtain the plurality of node steady-state vectors and the plurality of first pipe segment steady-state vectors before pipe burst.

[0259] The second solving sub-module is configured to solve the second steady-state hydraulic model based on the pipe network parameter set to obtain the plurality of second pipe segment steady-state vectors after pipe burst.

[0260] In some optional embodiments, the second construction module 505 includes:

[0261] The first construction sub-module is configured to construct a pipe network incidence matrix according to the pipe network parameter set.

[0262] The second construction sub-module is configured to construct a pipe segment hyperbolic function vector and a pipe segment impedance vector according to the pipe network parameter set, the Laplace frequency domain variable, the plurality of node steady-state vectors, the plurality of first pipe segment steady-state vectors and the plurality of second pipe segment steady-state vectors.

[0263] The third construction sub-module is configured to construct the frequency domain equation of transient flow of the pressurized pipe network according to the pipe network incidence matrix, the plurality of hydraulic boundary conditions, the pipe segment hyperbolic function vector and the pipe segment impedance vector.

[0264] In some optional embodiments, the third construction submodule comprises:

[0265] The first construction unit is configured to construct the decay exponential sequence.

[0266] The conversion unit is configured to convert the plurality of initial hydraulic boundary conditions in the frequency domain to obtain a plurality of target hydraulic boundary conditions by using the decay exponential sequence.

[0267] The second construction unit is configured to construct a transient flow frequency domain equation of the pressurized pipe network according to the pipe network association matrix, the pipe segment hyperbolic function vector, the pipe segment impedance vector, and the plurality of target hydraulic boundary conditions.

[0268] In some optional embodiments, the solution module 506 comprises:

[0269] The third solution submodule is configured to solve the transient flow frequency domain equation of the pressurized pipe network to obtain a transient flow frequency domain result of the pressurized pipe network.

[0270] The conversion submodule is configured to convert the transient flow frequency domain structure of the pressurized pipe network to obtain a pipe burst transient flow pressure change time sequence of the pressurized pipe network.

[0271] Further function descriptions of the above-mentioned modules and units are the same as those of the corresponding embodiments, and will not be repeated here.

[0272] The pressurized pipe network pipe burst transient flow pressure state determination apparatus in the embodiment is presented in the form of a functional unit. The unit herein refers to an ASIC (Application Specific Integrated Circuit, Application Specific Integrated Circuit) circuit, a processor and a memory executing one or more software or fixed programs, and / or other devices that can provide the above-mentioned functions.

[0273] The embodiment of the present application also provides a computer device with the above-mentioned Figure 5 pressurized pipe network pipe burst transient flow pressure state determination apparatus.

[0274] Please refer to Figure 6 , Figure 6 is a structural schematic diagram of a computer device provided by an optional embodiment of the present application, as Figure 6As shown, the computer device includes one or more processors 10, memory 20, and interfaces 30 for external devices such as a keyboard and a mouse and peripheral devices such as disk devices or other storage devices. One or more busses 10 can be used to implement the interface between the various circuits and components of the computer device. It will be appreciated that the bus 10 can be implemented using any one or more of a variety of bus structures, such as a Peripheral Component Interconnect (PCI) bus, a Bluetooth bus, an Industry Standard Architecture (ISA) bus, an Enhanced ISA bus, an Accelerated Graphics Port (AGP) bus, a Video Electronics Standards Association (VESA) local bus, a Micro Channel Architecture (MCA) bus, a Universal Serial Bus (USB), and the like. Figure 6 The processor 10 is used in the embodiments as an example.

[0275] The processor 10 can be a central processing unit, a network processor, or a combination thereof. The processor 10 can further include a hardware chip. The hardware chip can be an application specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device can be a complex programmable logic device, a field programmable logic device, a general array logic, or any combination thereof.

[0276] The memory 20 stores instructions that can be executed by the at least one processor 10, so that the at least one processor 10 can perform the method shown in the above embodiments.

[0277] The memory 20 can include a program region and a data region. The program region can store an operating system and application programs required by at least one function. The data region can store data created by the use of the computer device, and the like. In addition, the memory 20 can include a high-speed random access memory, and can further include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state memory device. In some alternative embodiments, the memory 20 can optionally include a memory disposed remotely with respect to the processor 10, and these remote memories can be connected to the computer device through a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0278] The memory 20 can include a volatile memory, such as a random access memory, and can also include a non-volatile memory, such as a flash memory, a hard disk, or a solid state disk. The memory 20 can further include a combination of the above-mentioned kinds of memories.

[0279] The computer device further includes a communication interface 30 for communication with other devices or communication networks.

[0280] The embodiments of the present application further provide a computer readable storage medium, and the method according to the embodiments of the present application can be implemented in hardware, firmware, or recorded in a storage medium, or stored in a remote storage medium or a non-transitory machine readable storage medium and downloaded to a local storage medium through network, so that the method described herein can be processed by such software on a storage medium using a general purpose computer, a special purpose processor, or programmable or special hardware. The storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid state disk, etc. Further, the storage medium can also include a combination of the above-mentioned memories. It can be understood that the computer, the processor, the microprocessor controller, or the programmable hardware includes a storage component that can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method shown in the above embodiments is implemented.

[0281] Part of the present application can be applied as a computer program product, for example, computer program instructions, when executed by a computer, the operation of the computer can invoke or provide the method and / or technical solutions according to the present application. Those skilled in the art should understand that the form of computer program instructions in computer readable medium includes but is not limited to source file, executable file, installation package file, etc. Correspondingly, the way of computer program instructions executed by computer includes but is not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Here, the computer readable medium can be any available computer readable storage medium or communication medium accessible to the computer.

[0282] Although the embodiments of the present application are described in conjunction with the accompanying drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A method for determining the transient flow pressure state of a burst pipe in a pressurized pipeline network, characterized in that, The method includes: Obtain the pipeline parameter set of the pressurized pipeline network system, the time period and time interval of the pipe burst event to be simulated, wherein the pipeline parameter set includes multiple pipe parameters, multiple constant flow node parameters, multiple constant pressure node parameters and multiple orifice outflow node parameters; Calculate the Laplace frequency domain variable of the simulated tube burst event based on the time period and the time interval; Construct the initial hydraulic boundary conditions for each node in the simulated pipe burst event based on the pipeline network parameter set; Based on the pipeline parameter set, steady-state hydraulic simulations were performed before and after the pipe burst, resulting in multiple node steady-state vectors before the pipe burst, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors after the pipe burst. Based on the pipeline network parameter set, the Laplace frequency domain variables, multiple hydraulic boundary conditions, multiple node steady-state vectors, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors, a pressurized pipeline network transient flow frequency domain equation is constructed. The frequency domain equation of the transient flow in the pressurized pipeline network is solved and the time series of transient flow pressure change in the pressurized pipeline network bursting is determined. The time series of transient flow pressure change in the pressurized pipeline network bursting is used to reflect the transient flow pressure change state of the pressurized pipeline network bursting. The transient flow frequency domain equations of the pressurized pipeline network are constructed based on the pipeline network parameter set, the Laplace frequency domain variables, the plurality of hydraulic boundary conditions, the plurality of node steady-state vectors, the plurality of first pipe segment steady-state vectors, and the plurality of second pipe segment steady-state vectors, including: Construct a pipeline network association matrix based on the pipeline network parameter set; Based on the pipeline parameter set, the Laplace frequency domain variable, the multiple node steady-state vectors, the multiple first pipe segment steady-state vectors, and the multiple second pipe segment steady-state vectors, construct the pipe segment hyperbolic function vector and the pipe segment impedance vector; Based on the pipeline network correlation matrix, the plurality of hydraulic boundary conditions, the hyperbolic function vector of the pipe segment, and the impedance vector of the pipe segment, the transient flow frequency domain equation of the pressurized pipeline network is constructed. The hyperbolic function vector of the pipe segment is expressed by the following relation: In the formula: Indicates the first The hyperbolic function vector corresponding to each frequency domain variable; , , They represent the 1st and the 2nd respectively. The and the first The length of each pipe; Indicates pipeline No. The transfer constants corresponding to each frequency domain variable are expressed by the following relationship: In the formula: This indicates the first simulated pipe burst event. One Laplace frequency domain variable; Indicates transient flow wave velocity; Indicates pipeline No. The friction term corresponding to each frequency domain variable is expressed by the following relationship: In the formula: Indicates pipeline The difference in flow rate between the steady state after the pipe burst and the steady state before the pipe burst; This represents the Darcy-Weisbach coefficient of friction. Indicates pipeline The diameter; Indicates pipeline The cross-sectional area of ​​the pipe; Indicates the first Steady-state flow rate before pipe rupture in a single pipe section; Indicates the first Flow rate after a pipe section bursts; Specifically, the transient flow frequency domain equations of the pressurized pipe network are constructed based on the pipe network correlation matrix, the plurality of hydraulic boundary conditions, the hyperbolic function vector of the pipe segment, and the impedance vector of the pipe segment, including: Construct a decay exponent sequence; The frequency domain transformation of the plurality of initial hydraulic boundary conditions is performed using the attenuation exponent sequence to obtain a plurality of target hydraulic boundary conditions; Based on the network correlation matrix, the hyperbolic function vector of the pipe segment, the impedance vector of the pipe segment, and the multiple target hydraulic boundary conditions, the transient flow frequency domain equation of the pressurized network is constructed. The transient current frequency domain equation of the pressurized pipeline network is expressed as the following relationship: In the formula: Represents the solution vector; This can be expressed as the following relation: In the formula: , , , and It is a diagonal matrix; and A network correlation matrix that reflects the connection relationships between pipelines and flow-regulating nodes; and A network correlation matrix representing the connection relationships between pipes and orifice outlet nodes; For each orifice outflow node The correction coefficients corresponding to each frequency domain variable are expressed by the following formula: in, ; The following relation applies: In the formula: This represents the orifice outflow coefficient in steady state before the pipe burst at the first orifice outflow node; Indicates the first One orifice outlet node; This represents the orifice outflow coefficient of the first orifice outflow node after the pipe burst has fully developed.

2. The method according to claim 1, characterized in that, Based on the time period and the time interval, calculate the Laplace frequency domain variables of the simulated tube burst event, including: Calculate the length of the pressure simulation result sequence for each pressurized pipeline node based on the time period and the time interval; The time series of the pipe rupture event to be simulated is determined based on the length of the pressure simulation result sequence. Based on the time series, calculate the Laplace frequency domain variable of the simulated tube burst event.

3. The method according to claim 1, characterized in that, Based on the pipeline parameter set, steady-state hydraulic simulations were performed before and after the pipe burst, yielding multiple node steady-state vectors before the burst, multiple first-segment steady-state vectors, and multiple second-segment steady-state vectors after the burst, including: Obtain the first steady-state hydraulic model before the pipe burst and the second steady-state hydraulic model after the pipe burst; Based on the pipeline parameter set, the first steady-state hydraulic model is solved to obtain the steady-state vectors of the multiple nodes and the steady-state vectors of the multiple first pipe segments before the pipe burst. Based on the pipeline parameter set, the second steady-state hydraulic model is solved to obtain the steady-state vectors of the multiple second pipe segments after the pipe burst.

4. The method according to claim 1, characterized in that, Solving the frequency domain equations of the transient flow in the pressurized pipeline network and determining the time series of pressure changes during the transient flow of the pressurized pipeline network bursting includes: Solve the frequency domain equations of the transient flow in the pressurized pipeline network to obtain the frequency domain results of the transient flow in the pressurized pipeline network; The transient flow frequency domain structure of the pressurized pipeline network is transformed into the time domain to obtain the time series of transient flow pressure changes in the pressurized pipeline network during pipe bursts.

5. A device for determining the transient flow pressure state of a burst pipe in a pressurized pipeline network, characterized in that, The device includes: The acquisition module is used to acquire the pipeline parameter set of the pressurized pipeline network system, the time period and time interval of the pipe burst event to be simulated, and the pipeline parameter set includes multiple pipe parameters, multiple constant flow node parameters, multiple constant pressure node parameters and multiple orifice outflow node parameters; The calculation module is used to calculate the Laplace frequency domain variable of the simulated tube burst event based on the time period and the time interval. The first construction module is used to construct the initial hydraulic boundary conditions of each node in the simulated pipe burst event based on the pipeline parameter set. The simulation module is used to perform steady-state hydraulic simulations before and after the pipe burst based on the pipeline parameter set, and to obtain multiple node steady-state vectors before the pipe burst, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors after the pipe burst. The second construction module is used to construct the transient flow frequency domain equation of the pressurized pipeline network based on the pipeline network parameter set, the Laplace frequency domain variables, multiple hydraulic boundary conditions, multiple node steady-state vectors, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors. The solution module is used to solve the frequency domain equation of the transient flow of the pressurized pipeline network and determine the time series of the transient flow pressure change of the pressurized pipeline network burst pipe. The time series of the transient flow pressure change of the pressurized pipeline network burst pipe is used to reflect the pressure change state of the transient flow of the pressurized pipeline network burst pipe. The second building module includes: The first construction submodule is used to construct a pipeline network association matrix based on the pipeline network parameter set; The second construction submodule is used to construct the hyperbolic function vector and the impedance vector of the pipe segment based on the pipeline parameter set, the Laplace frequency domain variable, the multiple node steady-state vectors, the multiple first pipe segment steady-state vectors and the multiple second pipe segment steady-state vectors; The third construction submodule is used to construct the transient flow frequency domain equation of the pressurized pipe network based on the pipe network correlation matrix, the plurality of hydraulic boundary conditions, the hyperbolic function vector of the pipe segment, and the impedance vector of the pipe segment; The hyperbolic function vector of the pipe segment is expressed by the following relation: In the formula: Indicates the first The hyperbolic function vector corresponding to each frequency domain variable; , , They represent the 1st and the 2nd respectively. The and the first The length of each pipe; Indicates pipeline No. The transfer constants corresponding to each frequency domain variable are expressed by the following relationship: In the formula: This indicates the first simulated pipe burst event. One Laplace frequency domain variable; Indicates transient flow wave velocity; Indicates pipeline No. The friction term corresponding to each frequency domain variable is expressed by the following relationship: In the formula: Indicates pipeline The difference in flow rate between the steady state after the pipe burst and the steady state before the pipe burst; This represents the Darcy-Weisbach coefficient of friction. Indicates pipeline The diameter; Indicates pipeline The cross-sectional area of ​​the pipe; Indicates the first Steady-state flow rate before pipe rupture in a single pipe section; Indicates the first Flow rate after a pipe section bursts; The third construction submodule includes: The first building unit is used to construct the decaying exponential sequence; A conversion unit is used to perform frequency domain conversion on the plurality of initial hydraulic boundary conditions using the attenuation exponent sequence to obtain a plurality of target hydraulic boundary conditions; The second construction unit is used to construct the transient flow frequency domain equation of the pressurized pipe network based on the pipe network correlation matrix, the pipe segment hyperbolic function vector, the pipe segment impedance vector, and the multiple target hydraulic boundary conditions. The transient current frequency domain equation of the pressurized pipeline network is expressed as the following relationship: In the formula: Represents the solution vector; This can be expressed as the following relation: In the formula: , , , and It is a diagonal matrix; and A network correlation matrix that reflects the connection relationships between pipelines and flow-regulating nodes; and A network correlation matrix representing the connection relationships between pipes and orifice outlet nodes; For each orifice outflow node The correction coefficients corresponding to each frequency domain variable are expressed by the following formula: in, ; The following relation applies: In the formula: This represents the orifice outflow coefficient in steady state before the pipe burst at the first orifice outflow node; Indicates the first One orifice outlet node; This represents the orifice outflow coefficient of the first orifice outflow node after the pipe burst has fully developed.

6. A computer device, characterized in that, include: The system includes a memory and a processor, which are interconnected. The memory stores computer instructions, and the processor executes the computer instructions to perform the method for determining the transient flow pressure state of a burst pipe in a pressurized pipeline network as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to execute the method for determining the transient flow pressure state of a burst pipe in a pressurized pipeline network as described in any one of claims 1 to 4.

8. A computer program product, characterized in that, Includes computer instructions, which are used to cause a computer to execute the method for determining the transient flow pressure state of a burst pipe in a pressurized pipeline network as described in any one of claims 1 to 4.

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