Method and device for determining transient flow pressure state of pipe explosion of pressure pipe network and medium

Abstract

The invention relates to the technical field of municipal engineering, and discloses a method and device for determining the transient flow pressure state of pipe explosion of a pressure pipe network and a medium. By calculating the Laplacian frequency domain variable of a pipe explosion event to be simulated, the pipe explosion event of the pressure pipe network can be converted from a time domain to a frequency domain to be analyzed, and the transient flow pressure state of the pressure pipe network is determined. According to the method, interpolation operation on time and space in a traditional method is avoided, a large amount of calculation and memory burdens are reduced, solutions at different frequencies are mutually independent, parallel calculation can be adopted, and therefore the calculation efficiency is greatly improved. Furthermore, by constructing initial hydraulic boundary conditions, the hydraulic state of each node when a pipe explosion event occurs is accurately described, then steady-state hydraulic simulation before and after pipe explosion is carried out respectively, and the accuracy of a simulation result is guaranteed. And finally, by constructing and solving a pressure pipe network transient flow frequency domain equation, the precision of the obtained pressure pipe network burst transient flow pressure change time sequence approaches to MOC, and meanwhile, the calculation efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal engineering, and particularly relates to a method, device and medium for determining the transient flow pressure state of a pressurized pipe network burst. Background Art

[0002] During the operation of a pressurized pipe network system, once a pipe burst suddenly occurs, the internal pressure of the pipe will drop rapidly, thereby triggering a transient flow event. The high-frequency pressure sensing devices deployed in the pipe network can monitor this transient flow event in real time and collect corresponding data. Further, by using the inverse problem analysis method to deeply analyze these monitoring data, theoretically, the specific location and scale of the pipe burst can be inferred. 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] Currently, in the related field, the method of characteristic (MOC) is widely used due to its advantages such as 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 process of interpolating time and space will cause a large number of calculation tasks and also has a high memory occupancy requirement, which undoubtedly increases the calculation cost and system burden; on the other hand, the calculation process based on MOC can only be advanced serially in sequence according to the time grid and cannot achieve parallel calculation, which to a certain extent limits the improvement of calculation efficiency.

[0004] In order to improve the calculation performance of transient flow pressure simulation, frequency domain analysis (FDA) has become a feasible research direction. Under specific assumption conditions, through certain mathematical transformations, the nonlinear part in the control equation is transformed into a linear form. After the linearization process is completed, with the help of Fourier transform or Laplace transform, the linearized control equation is transformed into the frequency domain space, and then solved analytically in the frequency domain. Compared with the traditional method, frequency domain solution has obvious advantages: firstly, solving in the frequency domain does not require spatial interpolation operations, reducing complex calculation steps; secondly, since the solutions at different frequencies are independent of each other, this makes parallel calculation possible, can make full use of multi-core computing resources, and greatly improves the calculation efficiency.

[0005] However, in the special scenario of a pressurized pipe network burst, the linearization assumption of the control equation relied on by frequency domain analysis is difficult to hold. The failure of this assumption condition will cause a large error when using FDA to calculate the burst pressure, seriously affecting the accuracy and reliability of the calculation results. Summary of the Invention

[0006] In view of this, the present invention provides a method, device and medium for determining the transient flow pressure state of a pressurized pipe network burst, so as to solve the problems of low calculation accuracy and low calculation efficiency of the existing accurate simulation calculation method for transient flow pressure.

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

[0008] Obtain the pipe network parameter set of the pressurized pipe network system, the time period and time interval of the to-be-simulated burst event, where the pipe network parameter set includes a plurality of pipe parameters, a plurality of fixed flow node parameters, a plurality of fixed pressure node parameters, and a plurality of orifice outflow node parameters; calculate the Laplace frequency domain variable of the to-be-simulated burst event according to the time period and time interval; construct the initial hydraulic boundary conditions of each node in the to-be-simulated burst event according to the pipe network parameter set; perform steady-state hydraulic simulations before and after the burst respectively according to the pipe network parameter set to obtain a plurality of node steady-state vectors before the burst, a plurality of first pipe section steady-state vectors, and a plurality of second pipe section steady-state vectors after the burst; construct a transient flow frequency domain equation of the pressurized pipe network 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; solve the transient flow frequency domain equation of the pressurized pipe network and determine the time series of the transient flow pressure change of the pressurized pipe network burst, and the time series of the transient flow pressure change of the pressurized pipe network burst is used to reflect the transient flow pressure change state of the pressurized pipe network burst.

[0009] The method for determining the transient flow pressure state of a pressurized pipe network burst provided by the present invention can accurately describe the structure, operating state of the pressurized pipe network and the time range of the pipe burst event by obtaining the pipe network parameter set of the pressurized pipe network system, the time period and time interval for simulating the pipe burst event, making the simulation more in line with the actual situation. Further, by calculating the Laplace frequency domain variables of the pipe burst event to be simulated, the pipe burst event of the pressurized pipe network can be analyzed by converting it from the time domain to the frequency domain, avoiding the interpolation operations for 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, and parallel computing can be adopted, thus greatly improving the computing efficiency. Further, according to the pipe network parameter set, the initial hydraulic boundary conditions of each node in the pipe burst event to be simulated are constructed, accurately describing the hydraulic state of each node when the pipe burst event occurs, and then the steady-state hydraulic simulations before and after the pipe burst are respectively carried out to ensure the accuracy of the simulation results. Finally, by comprehensively using the pipe network parameter set, Laplace frequency domain variables, hydraulic boundary conditions and steady-state vectors, a transient flow frequency domain equation of the pressurized pipe network is constructed and solved, maintaining a computing accuracy equivalent to that of the MOC, and then a time series of the transient flow pressure change of the pressurized pipe network burst that clearly reflects the change state of the transient flow pressure of the pressurized pipe network burst can be obtained, realizing the instant simulation of the transient pressure of the pressurized pipe network burst. Therefore, by implementing the present invention, while the accuracy of the obtained time series of the transient flow pressure change of the pressurized pipe network burst approaches that of the MOC, the computing efficiency is greatly improved.

[0010] In an optional implementation manner, calculating the Laplace frequency domain variables of the pipe burst event to be simulated according to the time period and time interval includes:

[0011] Calculating the sequence length of the pressure simulation results of each node of the pressurized pipe network according to the time period and time interval; determining the time series of the pipe burst event to be simulated according to the sequence length of the pressure simulation results; and calculating the Laplace frequency domain variables of the pipe burst event to be simulated according to the time series.

[0012] The method for determining the transient flow pressure state of a pressurized pipe network provided by the present invention clearly defines the simulation time range and time resolution through time periods and time intervals, and can thus determine the pressure simulation results of each node in the pressurized pipe network at each time point during the subsequent entire simulation process, thereby obtaining a complete sequence of pressure simulation results. Further, extracting the time information related to the pipe burst event to be simulated from the sequence of pressure simulation results of each node in the pressurized pipe network and forming a time series of the pipe burst event can focus more on the time process of the occurrence and development of the pipe burst event, removing the interference of other irrelevant information, and thus enabling a clearer study of the characteristics of the pipe burst event in the time dimension. Finally, calculating the Laplace frequency domain variables through the time series can transform the pipe burst event in the pressurized pipe network from the time domain to the frequency domain for analysis, avoiding the interpolation operations of time and space in traditional methods, reducing a large amount of calculation and memory burdens, and the solutions at different frequencies being independent of each other, allowing parallel computing, thereby greatly improving the computing efficiency.

[0013] In an alternative embodiment, steady-state hydraulic simulations are respectively performed before and after the pipe burst according to the pipe network parameter set to obtain multiple node steady-state vectors, multiple first pipe section steady-state vectors before the pipe burst, and multiple second pipe section steady-state vectors after the pipe burst, including:

[0014] Obtain a first steady-state hydraulic model before the pipe burst and a second steady-state hydraulic model after the pipe burst; based on the pipe network parameter set, solve the first steady-state hydraulic model to obtain multiple node steady-state vectors and multiple first pipe section steady-state vectors before the pipe burst; based on the pipe network parameter set, solve the second steady-state hydraulic model to obtain multiple second pipe section steady-state vectors after the pipe burst.

[0015] The method for determining the transient flow pressure state of a pressurized pipe network provided by the present invention can comprehensively and accurately describe the hydraulic parameters such as the pressure and flow rate of each node in the pressurized pipe network before and after the pipe burst, as well as the flow rate and other information of each pipe section by respectively solving the first steady-state hydraulic model before the pipe burst and the second steady-state hydraulic model after the pipe burst, providing an important basis for subsequent analysis of the impact of the pipe burst on the hydraulic characteristics of the pipe network and helping to more accurately construct the transient flow frequency domain equation.

[0016] In an alternative embodiment, a transient flow frequency domain equation of the pressurized pipe network is constructed according to the pipe network parameter set, Laplace frequency domain variables, multiple hydraulic boundary conditions, multiple node steady-state vectors, multiple first pipe section steady-state vectors, and multiple second pipe section steady-state vectors, including:

[0017] Construct a pipe network incidence matrix according to the pipe network parameter set; construct a pipe segment hyperbolic function vector and a pipe segment impedance vector according to the pipe network parameter set, Laplace frequency domain variables, multiple node steady-state vectors, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors; construct a frequency domain equation for transient flow in a pressurized pipe network according to the pipe network incidence matrix, multiple hydraulic boundary conditions, the pipe segment hyperbolic function vector, and the pipe segment impedance vector.

[0018] The method for determining the transient flow pressure state in a pressurized pipe network with pipe burst provided by the present invention constructs a pipe network incidence matrix through the pipe network parameter set, which can clearly reflect the connection relationship and topological structure between each pipeline and node in the pipe network. Further, by constructing a pipe segment hyperbolic function vector and a pipe segment impedance vector, the physical parameters, frequency domain characteristics, and steady-state operation state of the pipe network are comprehensively considered, and thus the hydraulic characteristics of the pipe segment during the pipe burst transient process can be accurately reflected. Finally, by combining the pipe network incidence matrix, hydraulic boundary conditions, pipe segment hyperbolic function vector, and pipe segment impedance vector and constructing a frequency domain equation for transient flow in a pressurized pipe network, the topological structure, hydraulic characteristics, boundary conditions, and frequency domain characteristics of the pipe network are comprehensively considered, and thus the physical process of transient flow in a pressurized pipe network with pipe burst can be accurately described, providing an effective mathematical model for solving the transient flow pressure change.

[0019] In an optional implementation manner, constructing a frequency domain equation for transient flow in a pressurized pipe network according to the pipe network incidence matrix, multiple hydraulic boundary conditions, the pipe segment hyperbolic function vector, and the pipe segment impedance vector includes:

[0020] Construct an attenuation exponent sequence; perform frequency domain conversion on multiple initial hydraulic boundary conditions by using the attenuation exponent sequence to obtain multiple target hydraulic boundary conditions; construct a frequency domain equation for transient flow in a pressurized pipe network according to the pipe network incidence matrix, the pipe segment hyperbolic function vector, the pipe segment impedance vector, and the multiple target hydraulic boundary conditions.

[0021] The method for determining the transient flow pressure state in a pressurized pipe network with pipe burst provided by the present invention constructs an attenuation exponent sequence and performs frequency domain conversion on multiple initial hydraulic boundary conditions by using this sequence, which can convert the boundary conditions in the time domain into the expression form in the frequency domain, and thus the boundary conditions can be made to match the frequency domain equation, providing appropriate boundary conditions for the solution of the frequency domain equation. Further, by comprehensively considering various factors such as the structure, hydraulic characteristics, and boundary conditions of the pipe network, the constructed frequency domain equation for transient flow in a pressurized pipe network can more accurately simulate the actual situation of transient flow in a pressurized pipe network with pipe burst, improving the accuracy and reliability of the simulation.

[0022] In an optional implementation manner, solving the frequency domain equation for transient flow in a pressurized pipe network and determining the time series of transient flow pressure change in a pressurized pipe network with pipe burst includes:

[0023] Solve the frequency-domain equation of transient flow in a pressurized pipeline network to obtain the frequency-domain results of transient flow in the pressurized pipeline network. Convert the frequency-domain structure of transient flow in the pressurized pipeline network to the time domain to obtain the time series of pressure changes in transient flow during pipeline rupture in the pressurized pipeline network.

[0024] The method for determining the pressure state of transient flow during pipeline rupture in a pressurized pipeline network provided by the present invention avoids complex spatial interpolation and serial calculation in traditional methods through frequency-domain solution, improving the calculation efficiency. Further, restoring the calculation results in the frequency domain to the actual time scale enables the time series of pressure changes in transient flow during pipeline rupture in the pressurized pipeline network to intuitively reflect the change of pressure in transient flow during pipeline rupture in the pressurized pipeline network, providing a direct reference basis for the actual operation and management of the pipeline network.

[0025] In a second aspect, the present invention provides a device for determining the pressure state of transient flow during pipeline rupture in a pressurized pipeline network, the device comprising:

[0026] An acquisition module for acquiring a pipeline network parameter set of a pressurized pipeline network system, a time period and a time interval of a pipeline rupture event to be simulated, the pipeline network parameter set including a plurality of pipeline parameters, a plurality of fixed-flow node parameters, a plurality of fixed-pressure node parameters, and a plurality of orifice outflow node parameters; a calculation module for calculating the Laplace frequency-domain variables of the pipeline rupture event to be simulated according to the time period and the time interval; a first construction module for constructing the initial hydraulic boundary conditions of each node in the pipeline rupture event to be simulated according to the pipeline network parameter set; a simulation module for respectively performing steady-state hydraulic simulations before and after the pipeline rupture according to the pipeline network parameter set to obtain a plurality of node steady-state vectors, a plurality of first pipeline segment steady-state vectors before the pipeline rupture, and a plurality of second pipeline segment steady-state vectors after the pipeline rupture; a second construction module for constructing a frequency-domain equation of transient flow in the pressurized pipeline network according to the pipeline network parameter set, the Laplace frequency-domain variables, a plurality of hydraulic boundary conditions, a plurality of node steady-state vectors, a plurality of first pipeline segment steady-state vectors, and a plurality of second pipeline segment steady-state vectors; a solution module for solving the frequency-domain equation of transient flow in the pressurized pipeline network and determining the time series of pressure changes in transient flow during pipeline rupture in the pressurized pipeline network, the time series of pressure changes in transient flow during pipeline rupture in the pressurized pipeline network being used to reflect the pressure change state of transient flow during pipeline rupture in the pressurized pipeline network.

[0027] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, which are communicatively connected to each other, wherein the memory stores computer instructions, and the processor executes the computer instructions to execute the method for determining the pressure state of transient flow during pipeline rupture in a pressurized pipeline network according to the first aspect or any corresponding embodiment thereof.

[0028] In a fourth aspect, the present invention provides a computer-readable storage medium, on which computer instructions are stored, and the computer instructions are used to cause a computer to execute the method for determining the pressure state of transient flow during pipeline rupture in a pressurized pipeline network according to the first aspect or any corresponding embodiment thereof.

[0029] In a fifth aspect, the present invention provides a computer program product, including computer instructions for causing a computer to execute the method for determining the pressure state of transient flow in a pressurized pipe network burst according to the first aspect or any corresponding embodiment thereof described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 is a schematic flowchart of the method for determining the pressure state of transient flow in a pressurized pipe network burst according to an embodiment of the present invention;

[0032] Figure 2 is a schematic flowchart of another method for determining the pressure state of transient flow in a pressurized pipe network burst according to an embodiment of the present invention;

[0033] Figure 3 is a schematic flowchart of yet another method for determining the pressure state of transient flow in a pressurized pipe network burst according to an embodiment of the present invention;

[0034] Figure 4 is a topological structure diagram of a pipe network according to an embodiment of the present invention;

[0035] Figure 5 is a structural block diagram of a device for determining the pressure state of transient flow in a pressurized pipe network burst according to an embodiment of the present invention;

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

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0038] An embodiment of the present invention provides a method for determining the transient flow pressure state of a pressurized pipe network. By analyzing the pipe burst event of the pressurized pipe network in the frequency domain instead of the time domain, it avoids the interpolation operations of time and space in traditional methods, reduces a large amount of calculation and memory burden, and the solutions at different frequencies are independent of each other, so parallel computing can be adopted, thus greatly improving the computing efficiency.

[0039] According to an embodiment of the present invention, there is provided an embodiment of a method for determining the transient flow pressure state of a pressurized pipe network. It should be noted that the steps shown in the flowchart of the accompanying drawings 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 a different order than here.

[0040] In this embodiment, a method for determining the transient flow pressure state of a pressurized pipe network is provided, which can be used in electronic devices such as computers, mobile phones, and tablet computers. Figure 1 It is a flowchart of a method for determining the transient flow pressure state of a pressurized pipe network according to an embodiment of the present invention, as Figure 1 shown, and this process includes the following steps:

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

[0042] Among them, the pipe network parameter set may include multiple pipe parameters, multiple fixed-flow node parameters, multiple fixed-pressure node parameters, and multiple orifice outflow node parameters.

[0043] Specifically, multiple pipe parameters are used to describe the physical characteristics of each pipe in the pipe network. Suppose there are ξ pipes in the pressurized pipe network system, then the pipes in the pipe network can be denoted as p, where p = 1, 2,..., ξ. For pipe p, multiple pipe parameters may include the starting node and ending node of the pipe, the pipe length l p , diameter D p , Darcy-Weisbach friction coefficient f p , transient flow wave speed a p , pipe cross-sectional area A p .

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

[0045] Furthermore, a fixed-flow node represents a node with a known outflow in both steady-state and transient processes. Assuming there are α fixed-flow nodes in the pipe network, the fixed-flow nodes in the pipe network can be denoted as i, where i = 1, 2, …, α. For the fixed-flow node i, the fixed-flow node parameter records the outflow before the pipe burst in the steady state. It is used to reflect the water flow out situation of each fixed-flow node in the pipe network before the pipe burst, and is an important basis for determining the initial hydraulic state of the pipe network. It is used to set boundary conditions and calculate relevant parameters in subsequent steady-state hydraulic simulation and frequency-domain equation construction.

[0046] Furthermore, a fixed-pressure node represents a node with a known piezometric head at the pressure measurement point in both steady-state and transient processes. Assuming there are β fixed-pressure nodes in the pipe network, the fixed-pressure nodes in the pipe network can be denoted as j, where j = 1, 2, …, β. For the fixed-pressure node j, the fixed-pressure node parameter records the piezometric head before the pipe burst in the steady state. It is used for the pressure state of each fixed-pressure node in the pipe network before the pipe burst, and is also used to set boundary conditions and calculations in subsequent steady-state hydraulic simulation and frequency-domain equation construction.

[0047] Furthermore, an orifice outflow node represents a node in both steady-state and transient processes, for which it can be considered that the outflow and service head satisfy the following relation (1) of orifice outflow:

[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 where the 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 location.

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

[0051] Furthermore, without loss of generality, let the pipe burst node to be simulated be the orifice outflow node numbered 1, and set After the pipe burst is fully developed, the orifice outflow coefficient of the node is

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

[0053] Further, the time period T of the to-be-simulated pipe burst event represents the set duration 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 expected pressure change process 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 computational amount and calculation time will increase. 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 two adjacent simulation moments during the simulation of the pipe burst process, which determines the time resolution of the simulation results and affects the accuracy and computational amount of the simulation data.

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

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

[0058] Specifically, by calculating the Laplace frequency domain variable of the to-be-simulated pipe burst event, the pipe burst event in the pressurized pipe network can be transformed from the time domain to the frequency domain for analysis, avoiding the interpolation operations 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, and parallel computing can be adopted, thereby greatly improving the computational efficiency.

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

[0060] Among them, the initial hydraulic boundary conditions in the to-be-simulated pipe burst event may include the initial hydraulic boundary conditions of the constant flow node, the initial hydraulic boundary conditions of the constant pressure node, and the initial hydraulic boundary conditions of the orifice outflow node.

[0061] First, set the function of the outflow rate of each constant flow node with respect to time t in the pipe burst event As shown in the following relational expression (2):

[0062]

[0063] In the formula: represents the outflow at the steady state before the pipe burst occurs at the constant-flow node i; u i (t) represents the change in the outflow at the constant-flow node i.

[0064] Furthermore, the time series (vector) of the change in the outflow at the constant-flow node i can be determined, as shown in the following relational expression (3):

[0065] u i,: = [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 constant-flow node can be constructed to reflect the change in the outflow of the constant-flow node over time during the pipe burst process.

[0070] Secondly, set the function of the water head of each constant-pressure node with respect to time t during the pipe burst event as shown in the following relational expression (6):

[0071]

[0072] In the formula: represents the water head at the steady state before the pipe burst occurs at the constant-pressure node j; r j (t) represents the change in the water head of the constant-pressure node j.

[0073] Furthermore, the time series (vector) of the change in the water head of the constant-pressure node j can be determined, as shown in the following relational expression (7):

[0074] r j,: = [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 can be constructed to reflect the variation of the water head of the constant-pressure node with time during the pipe burst process.

[0077] Finally, set the function of the orifice outflow coefficient of each orifice outflow node with respect to time during the pipe burst event as shown in the following relation (8):

[0078]

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

[0080] Furthermore, the time series (vector) of the change in the orifice outflow coefficient at the orifice outflow node k can be determined, as shown in the following relation (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 orifice outflow node can be constructed to reflect the influence of the change in the orifice outflow coefficient of the orifice outflow node on the hydraulic characteristics of the pipe network during the pipe burst process.

[0084] Step S104: Perform steady-state hydraulic simulations before and after the pipe burst respectively according to the pipe network parameter set, and obtain multiple node steady-state vectors, multiple first pipe segment steady-state vectors before the pipe burst, and multiple second pipe segment steady-state vectors after the pipe burst.

[0085] Among them, the multiple node steady-state vectors before the pipe burst represent the relevant parameter vectors of each node when the pipe network system is in a stable state before the pipe burst event, and may include:

[0086] (1) The piezometric head vector of the constant-flow node at the steady state before the pipe burst as shown in the following relation (10):

[0087]

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

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

[0090]

[0091] Wherein: represents the steady-state outflow rate before pipe burst at the k-th orifice outflow node.

[0092] (3) Steady-state service head vector before pipe burst at the orifice outflow node As shown in the following relationship (12):

[0093]

[0094] Wherein: represents the steady-state service head value before pipe burst at the k-th orifice outflow node.

[0095] (4) Steady-state orifice outflow coefficient vector before pipe burst at the orifice outflow node As shown in the following relationship (13):

[0096]

[0097] Furthermore, a pipe segment is a part connecting nodes. Therefore, the first pipe segment steady-state vector represents the flow rate vector of each pipe segment before the pipe burst event As shown in the following relationship (14):

[0098]

[0099] Wherein: represents the steady-state flow rate before pipe burst at the p-th pipe segment.

[0100] Furthermore, the second pipe segment steady-state vector represents the flow rate vector of each pipe segment after the pipe burst event As shown in the following relationship (15):

[0101]

[0102] Wherein: represents the flow rate after pipe burst at the p-th pipe segment.

[0103] Step S105, construct a frequency-domain equation for transient flow in a pressurized pipe network according to the pipe network parameter set, 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.

[0104] Among them, the transient flow in a pressurized pipe network refers to the pressure and flow velocity fluctuations caused by sudden changes in the flow velocity of the fluid in the pipe network (such as pipe bursts, rapid opening and closing of valves, etc.); the frequency-domain equation of the transient flow in a pressurized pipe network represents a mathematical model that transforms the transient flow problem in a pressurized pipe network from the time domain to the frequency domain for analysis.

[0105] Specifically, when dealing with such problems, the traditional time-domain analysis method has a large amount of calculation and high memory occupancy. In this embodiment, by comprehensively considering the pipe network parameter set, Laplace frequency-domain variables, hydraulic boundary conditions, and steady-state vectors and constructing the frequency-domain equation of the transient flow in a pressurized pipe network, the transient flow problem in the time domain can be transformed to the frequency domain for solution through Laplace transform. Furthermore, it can effectively reduce the subsequent calculation amount and memory burden, and parallel computing can also be adopted to greatly improve the computing efficiency.

[0106] Step S106: Solve the frequency-domain equation of the transient flow in a pressurized pipe network and determine the time series of the pressure change of the transient flow in the pressurized pipe network due to a pipe burst.

[0107] Specifically, by solving the frequency-domain equation of the transient flow in a pressurized pipe network, a calculation accuracy equivalent to that of the MOC is maintained. Furthermore, a time series of the pressure change of the transient flow in the pressurized pipe network due to a pipe burst that clearly reflects the change state of the pressure of the transient flow in the pressurized pipe network due to a pipe burst can be obtained, realizing the instant simulation of the transient pressure of the pipe burst in the pressurized pipe network.

[0108] The method for determining the transient flow pressure state of a pressurized pipe network burst provided in this embodiment can accurately describe the structure, operating state of the pressurized pipe network, and the time range of the pipe burst event by obtaining the pipe network parameter set of the pressurized pipe network system, the time period and time interval for simulating the pipe burst event, making the simulation more in line with the actual situation. Further, by calculating the Laplace frequency-domain variables of the pipe burst event to be simulated, the pipe burst event of the pressurized pipe network can be transformed from the time domain to the frequency domain for analysis, avoiding the interpolation operations 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, and parallel computing can be used, thus greatly improving the computing efficiency. Further, according to the pipe network parameter set, the initial hydraulic boundary conditions of each node in the pipe burst event to be simulated are constructed, accurately describing the hydraulic state of each node when the pipe burst event occurs, and then the steady-state hydraulic simulations before and after the pipe burst are respectively carried out to ensure the accuracy of the simulation results. Finally, by comprehensively using the pipe network parameter set, Laplace frequency-domain variables, hydraulic boundary conditions, and steady-state vectors to construct the transient flow frequency-domain equation of the pressurized pipe network and solve it, the calculation accuracy equivalent to that of MOC is maintained, and then a time series of the transient flow pressure change of the pressurized pipe network burst that clearly reflects the change state of the transient flow pressure of the pressurized pipe network burst can be obtained, realizing the instant simulation of the transient pressure of the pressurized pipe network burst. Therefore, by implementing the present invention, while the accuracy of the obtained time series of the transient flow pressure change of the pressurized pipe network burst approaches that of MOC, the computing efficiency is greatly improved.

[0109] In this embodiment, a method for determining the transient flow pressure state of a pressurized pipe network burst is provided, which can be used in electronic devices such as computers, mobile phones, and tablet computers. Figure 2 It is a flowchart of the method for determining the transient flow pressure state of a pressurized pipe network burst according to an embodiment of the present invention, as Figure 2 shown, and this process includes the following steps:

[0110] Step S201, obtain the pipe network parameter set of the pressurized pipe network system, the time period and time interval of the pipe burst event to be simulated. For details, please refer to Figure 1 Step S101 of the shown embodiment, which will not be elaborated here.

[0111] Step S202, calculate the Laplace frequency-domain variables of the pipe burst event to be simulated according to the time period and time interval.

[0112] Specifically, the above step S202 includes:

[0113] Step S2021, calculate the sequence length of the pressure simulation results of each pressurized pipe network node according to the time period and time interval.

[0114] Specifically, the pressure simulation results of each pressurized pipe network node in the pipe network are sequences of length N. Among them, the length N is shown in the following relational expression (16):

[0115]

[0116] Therefore, through 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 and obtained.

[0117] Step S2022: Determine the time sequence of the pipe burst events to be simulated according to the length of the pressure simulation result sequence.

[0118] Among them, the time sequence of the pipe burst events to be simulated represents the sequence (vector) of the moments corresponding to the simulation results.

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

[0120] t = [t1, …, t n , …, t N (17)

[0121] Among them, t N can be obtained through the above relational expression (5).

[0122] Step S2023: Calculate the Laplace frequency domain variables of the pipe burst events to be simulated according to the time sequence.

[0123] Among them, 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 pipe burst events to be simulated is shown in the following relational expression (18):

[0125] ζ = [ζ1, …, ζ m , …, ζ N (18)

[0126] Among them, ζ m is shown in the following relational expression (19):

[0127]

[0128] In the formula: represents the imaginary unit σ represents the convergence exponent of the Laplace transform and can be selected according to the following relational expression (20):

[0129]

[0130] Calculating Laplace frequency-domain variables through time series can transform the burst events in the pressurized pipe network from the time domain to the frequency domain for analysis, avoiding the interpolation operations of time and space in traditional methods, reducing a large amount of calculation and memory burden, and the solutions at different frequencies are independent of each other, so parallel computing can be adopted, thus greatly improving the calculation efficiency.

[0131] Step S203: Construct the initial hydraulic boundary conditions of each node in the to-be-simulated burst event according to the pipe network parameter set. For details, please refer to Figure 1 Step S103 of the embodiment shown, which will not be elaborated here.

[0132] Step S204: Perform steady-state hydraulic simulations before and after the burst respectively according to the pipe network parameter set, and obtain multiple node steady-state vectors, multiple first pipe section steady-state vectors before the burst, and multiple second pipe section steady-state vectors after the burst.

[0133] Specifically, the above step S204 includes:

[0134] Step S2041: Obtain the first steady-state hydraulic model before the burst and the second steady-state hydraulic model after the burst.

[0135] Among them, the first steady-state hydraulic model comprehensively considers the flow of fluids in the pipe network, energy losses, and the interaction relationships between each node and pipe section, and can present the hydraulic characteristics of the pipe network in a stable state in the form of mathematical equations; the second steady-state hydraulic model can reflect the impact of the burst on the fluid flow, pressure distribution, and hydraulic parameters of each node and pipe section in the pipe network.

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

[0137] Furthermore, after setting the location and related parameters of the burst (such as setting the burst location as an orifice outflow node and changing its orifice outflow coefficient to simulate the severity of the burst), based on the pipe network parameter set and combined with the changes in the hydraulic state of the pipe network after the burst, the same or similar hydraulic analysis software can be used to establish the second steady-state hydraulic model that can reflect the pipe network system when it reaches a certain stable state after the burst.

[0138] Step S2042: Based on the pipe network parameter set, solve the first steady-state hydraulic model to obtain multiple node steady-state vectors and multiple first pipe section steady-state vectors before pipe burst.

[0139] Specifically, input the pipe network parameter set into the first steady-state hydraulic model for solution, and multiple node steady-state vectors shown in the above relationships (10) to (13) and the first pipe section steady-state vectors of each pipe section shown in relationship (14) can be obtained.

[0140] Step S2043: Based on the pipe network parameter set, solve the second steady-state hydraulic model to obtain multiple second pipe section steady-state vectors after pipe burst.

[0141] Specifically, input the pipe network parameter set into the second steady-state hydraulic model for solution, and the second pipe section steady-state vectors of each pipe section shown in the above relationship (15) can be obtained.

[0142] Step S205: According to the pipe network parameter set, Laplace frequency-domain variables, multiple hydraulic boundary conditions, multiple node steady-state vectors, multiple first pipe section steady-state vectors, and multiple second pipe section steady-state vectors, construct a frequency-domain equation for transient flow in a pressurized pipe network. For details, please refer to Figure 1 Step S105 of the embodiment shown, which will not be elaborated here.

[0143] Step S206: Solve the frequency-domain equation for transient flow in a pressurized pipe network and determine the time series of transient flow pressure changes in the pressurized pipe network during pipe burst. For details, please refer to Figure 1 Step S106 of the embodiment shown, which will not be elaborated here.

[0144] The method for determining the transient flow pressure state of a pressurized pipe network burst provided in this embodiment clearly defines the simulation time range and time resolution through the time period and time interval. Furthermore, during the subsequent entire simulation process, the pressure simulation results of each node in the pressurized pipe network can be determined at each time point, thereby obtaining a complete sequence of pressure simulation results. Further, by extracting the time information related to the to-be-simulated pipe burst event from the sequence of pressure simulation results of each node in the pressurized pipe network and forming a time series of the pipe burst event, it is possible to focus more on the time process of the occurrence and development of the pipe burst event, eliminate the interference of other irrelevant information, and thus be able to more clearly study the characteristics of the pipe burst event in the time dimension. Finally, by calculating the Laplace frequency domain variables through the time series, the pipe burst event in the pressurized pipe network can be transformed from the time domain to the frequency domain for analysis, avoiding the interpolation operations in 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, and parallel computing can be adopted, thereby greatly improving the computing efficiency. Further, by separately solving the first steady-state hydraulic model before the pipe burst and the second steady-state hydraulic model after the pipe burst, it is possible to comprehensively and accurately describe the hydraulic parameters such as the pressure and flow rate of each node in the pressurized pipe network before and after the pipe burst, as well as the flow rate and other information of each pipe segment, providing an important basis for subsequent analysis of the impact of the pipe burst on the hydraulic characteristics of the pipe network, and contributing to more accurately constructing the transient flow frequency domain equation.

[0145] In this embodiment, a method for determining the transient flow pressure state of a pressurized pipe network burst is provided, which can be used in electronic devices such as computers, mobile phones, and tablet computers. Figure 3 It is a flowchart of the method for determining the transient flow pressure state of a pressurized pipe network burst according to an embodiment of the present invention, as Figure 3 shown, and this process includes the following steps:

[0146] Step S301, obtain the pipe network parameter set of the pressurized pipe network system, the time period and time interval of the to-be-simulated pipe burst event. For details, please refer to Figure 1 step S101 of the embodiment shown herein, which will not be elaborated herein.

[0147] Step S302, calculate the Laplace frequency domain variables of the to-be-simulated pipe burst event according to the time period and time interval. For details, please refer to Figure 2 step S202 of the embodiment shown herein, which will not be elaborated herein.

[0148] Step S303, construct the initial hydraulic boundary conditions of each node during the to-be-simulated pipe burst event according to the pipe network parameter set. For details, please refer to Figure 1 step S103 of the embodiment shown herein, which will not be elaborated herein.

[0149] Step S304: Perform steady-state hydraulic simulations before and after pipe burst respectively according to the pipe network parameter set, to obtain multiple node steady-state vectors, multiple first pipe segment steady-state vectors before pipe burst, and multiple second pipe segment steady-state vectors after pipe burst. For details, please refer to Figure 2 Step S204 of the embodiment shown, which will not be elaborated here.

[0150] Step S305: Construct a frequency-domain equation for transient flow in a pressurized pipe network according to the pipe network parameter set, 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.

[0151] Specifically, the above Step S305 includes:

[0152] Step S3051: Construct a pipe network incidence matrix according to the pipe network parameter set.

[0153] Specifically, for pipe p and fixed-flow node i, the following incidence matrix M with dimensions ξ×α can be defined 1D and M 1U , and the elements in the matrix are shown in the following relational expressions (21) and (22) respectively:

[0154]

[0155] Furthermore, for pipe p and fixed-pressure node j, the following incidence matrix M with dimensions ξ×β can be defined 2D and M 2U , and the elements in the matrix are shown in the following relational expressions (23) and (24) respectively:

[0156]

[0157] Furthermore, for pipe p and orifice outflow node k, the following incidence matrix M with dimensions ξ×γ can be defined 3D and M 3U , and the elements in the matrix are shown in the following relational expressions (25) and (26) respectively:

[0158]

[0159] Constructing a pipe network incidence matrix through the pipe network parameter set can clearly reflect the connection relationship and topological structure between each pipe and node in the pipe network.

[0160] Step S3052: Construct a hyperbolic function vector and an impedance vector for the pipe segments according to the pipe network parameter set, Laplace frequency-domain variables, multiple node steady-state vectors, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors.

[0161] Specifically, the hyperbolic function vector c corresponding to the mth frequency-domain variable :,mAs shown in the following relational expression (27):

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

[0163] Where: μ p,m represents the transfer constant corresponding to the m-th frequency domain variable of pipeline p, as shown in the following relational expression (28):

[0164]

[0165] Where: R p,m represents the friction term corresponding to the m-th frequency domain variable of pipeline p, as shown in the following relational expression (29):

[0166]

[0167] Where: Δq p represents the flow rate difference between the steady state after pipeline p bursts and the steady state before bursting, as shown in the following relational expression (30):

[0168]

[0169] Similarly, the hyperbolic function vector s :,m corresponding to the m-th frequency domain variable, as shown in the following relational expression (31):

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

[0171] Furthermore, the impedance vector z :,m corresponding to the m-th frequency domain variable, as shown in the following relational expression (32):

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

[0173] Where: z p,m represents the impedance corresponding to the m-th frequency domain variable of pipeline p, as shown in the following relational expression (33):​

[0174]

[0175] Where: g represents the acceleration due to gravity.

[0176] Furthermore, by substituting the known pipe network parameter set, Laplace frequency-domain variables, multiple node steady-state vectors, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors into the corresponding relational expressions above, the corresponding pipe segment hyperbolic function vectors and pipe segment impedance vectors can be constructed.

[0177] Step S3053: Construct a frequency-domain equation for transient flow in a pressurized pipe network based on the pipe network incidence matrix, multiple hydraulic boundary conditions, pipe segment hyperbolic function vectors, and pipe segment impedance vectors.

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

[0179] In some alternative embodiments, the above step S3053 includes:

[0180] Step a1: Construct a sequence of attenuation exponents.

[0181] Step a2: Perform frequency-domain conversion on multiple initial hydraulic boundary conditions using the sequence of attenuation exponents to obtain multiple target hydraulic boundary conditions.

[0182] Step a3: Construct a frequency-domain equation for transient flow in a pressurized pipe network based on the pipe network incidence matrix, pipe segment hyperbolic function vectors, pipe segment impedance vectors, and multiple target hydraulic boundary conditions.

[0183] Specifically, construct a sequence of attenuation exponents as shown in the following relational expression (34):

[0184] y = [y1,…,y n ,…,y N (34)

[0185] where y n is as shown in the following relational expression (35):

[0186] y n = exp(-σ·t n ) (35)

[0187] Where: exp represents the exponential function.

[0188] Furthermore, use to represent element-wise multiplication of vectors, and for the hydraulic boundary condition u of the constant flow node i,:Convert to the frequency domain as shown in the following relational expression (36):

[0189]

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

[0191]

[0192] In the formula: Denote the relevant value of the outflow corresponding to the m-th frequency domain variable of the constant-flow node i in the frequency domain.

[0193] Furthermore, convert the boundary condition r of the constant-pressure node j j,: to the frequency domain as shown in the following relational expression (38):

[0194]

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

[0196]

[0197] In the formula: Denote the relevant value of the water head corresponding to the m-th frequency domain variable of the constant-pressure node j in the frequency domain.

[0198] Furthermore, convert the boundary condition θ of the orifice outflow node k k,: to the frequency domain as shown in the following relational expression (40):

[0199]

[0200] In the formula: Denote 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 relational expression (41):

[0201]

[0202] In the formula: Denote the relevant value of the orifice outflow coefficient corresponding to the m-th frequency domain variable of the orifice outflow node k in the frequency domain.

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

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

[0205] wherein, A m is as shown in the following relational expression (43):

[0206]

[0207] wherein, Φ, Ψ, C m , S m and Z m are diagonal matrices, and are respectively as shown in the following relational expressions (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] Furthermore, Λ m is also a diagonal matrix, which is the correction coefficient corresponding to the m-th frequency domain variable of each orifice outflow node, as shown in the following relational expression (49):

[0214] Λ m = diag(λ :,m ) (49)

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

[0216] Furthermore, the value of λ k,m is as shown in the following relational expression (50):

[0217]

[0218] Furthermore, b m is as shown in the following relational expression (51):

[0219]

[0220] Wherein:

[0221] ​

[0222] Furthermore, Θ is a diagonal matrix, as shown in the following relational expression (55):

[0223]

[0224] Furthermore, x m is a solution vector, as shown in the following relational expression (56):

[0225]

[0226] wherein:

[0227]

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

[0229] Step S306: Solve the frequency domain equation of the transient flow in the pressurized pipe network and determine the time series of the transient flow pressure change in the pressurized pipe network during a pipe burst.

[0230] Specifically, the above-mentioned step S306 includes:

[0231] Step S3061: Solve the frequency domain equation of the transient flow in the pressurized pipe network to obtain the frequency domain result of the transient flow in the pressurized pipe network.

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

[0233] Step S3062: Perform a time domain conversion on the frequency domain structure of the transient flow in the pressurized pipe network to obtain the time series of the transient flow pressure change in the pressurized pipe network during a pipe burst.

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

[0235]

[0236] Furthermore, the pressure at each node is as shown in the following relational expressions (63) to (64):

[0237]

[0238] wherein, Denote the time series of the pressure change of the constant-flow node \(i\) to be determined; Denote the time series of the pressure change of the orifice outflow node \(k\) to be determined.

[0239] The method for determining the transient flow pressure state of a pressurized pipe network burst provided in this embodiment constructs a pipe network incidence matrix through a set of pipe network parameters, which can clearly reflect the connection relationship and topological structure between each pipe and node in the pipe network. Further, by constructing the hyperbolic function vector of the pipe section and the impedance vector of the pipe section, 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 during the burst transient process can be accurately reflected. Further, by constructing an attenuation index sequence and using this sequence to perform frequency domain conversion on multiple initial hydraulic boundary conditions, the boundary conditions in the time domain can be converted into the expression form in the frequency domain, and thus the boundary conditions can be matched with the frequency domain equation, providing appropriate boundary conditions for the solution of the frequency domain equation. Further, by comprehensively considering various factors such as the structure, hydraulic characteristics, and boundary conditions of the pipe network, the constructed frequency domain equation of the transient flow in the pressurized pipe network can more accurately simulate the actual situation of the transient flow of the pressurized pipe network burst, improving the accuracy and reliability of the simulation. Further, through frequency domain solution, the complex spatial interpolation and serial calculation in the traditional method are avoided, improving the calculation efficiency. Further, restoring the calculation result in the frequency domain to the actual time scale enables the time series of the pressure change of the transient flow of the pressurized pipe network burst to intuitively reflect the change of the pressure of the transient flow of the pressurized pipe network burst over time, 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 transient flow pressure state of a pressurized pipe network burst provided in this embodiment.

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

[0242] Assume that the burst occurs at node J124, and the burst flow rate is 4.1 L / s, as Figure 4As shown by the middle triangle. The burst pipe node itself is included, and a total of 8 nodes in the pipe network are selected as example nodes to demonstrate the effectiveness of the rapid calculation method for the pressure state of burst pipes. When selecting the example nodes, they are evenly distributed in the pipe network and can represent various parts of the pipe network (such as Figure 4 as shown by the middle circle). By using the traditional MOC and the rapid calculation method for the pressure state of burst pipes proposed in this paper, the time series of the pressure change of burst pipes at the example nodes are calculated respectively, and the two are compared. The total duration of the simulated pipeline pressure change is 30 s, and the simulation time interval is 0.004 s.

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

[0244] In this embodiment, a device for determining the pressure state of transient flow in a pressurized pipe network with burst pipes is also provided. This device is used to implement the above-mentioned embodiments and preferred implementation manners, and those that have been described will not be repeated. As used below, the term "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0245] This embodiment provides a device for determining the pressure state of transient flow in a pressurized pipe network with burst pipes, as Figure 5 shown. This device includes:

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

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

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

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

[0250] A second construction module 505 for constructing a frequency-domain equation for transient flow in a pressurized pipe network according to a pipe network parameter set, 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.

[0251] A solution module 506 for solving the frequency-domain equation for transient flow in a pressurized pipe network and determining a time series of pressure changes in transient flow due to pipe burst in the pressurized pipe network, where the time series of pressure changes in transient flow due to pipe burst in the pressurized pipe network is used to reflect the state of pressure changes in transient flow due to pipe burst in the pressurized pipe network.

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

[0253] A first calculation sub-module for calculating the length of the pressure simulation result sequence for each node in the pressurized pipe network according to a time period and a time interval.

[0254] A determination sub-module for determining a time series of pipe burst events to be simulated according to the length of the pressure simulation result sequence.

[0255] A second calculation sub-module for calculating the Laplace frequency-domain variables of the pipe burst events to be simulated according to the time series.

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

[0257] An acquisition sub-module for acquiring a first steady-state hydraulic model before pipe burst and a second steady-state hydraulic model after pipe burst.

[0258] A first solution sub-module for solving the first steady-state hydraulic model based on the pipe network parameter set to obtain multiple node steady-state vectors and multiple first pipe segment steady-state vectors before pipe burst.

[0259] A second solution sub-module for solving the second steady-state hydraulic model based on the pipe network parameter set to obtain multiple second pipe segment steady-state vectors after pipe burst.

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

[0261] A first construction sub-module for constructing a pipe network incidence matrix according to the pipe network parameter set.

[0262] A second construction sub-module for constructing a pipe segment hyperbolic function vector and a pipe segment impedance vector according to the pipe network parameter set, Laplace frequency-domain variables, multiple node steady-state vectors, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors.

[0263] A third construction sub-module for constructing a frequency-domain equation for transient flow in a pressurized pipe network according to the pipe network incidence matrix, multiple hydraulic boundary conditions, the pipe segment hyperbolic function vector, and the pipe segment impedance vector.

[0264] In some alternative embodiments, the third construction sub-module includes:

[0265] A first construction unit for constructing a decay exponential sequence.

[0266] A conversion unit for performing frequency-domain conversion on a plurality of initial hydraulic boundary conditions by using the decay exponential sequence to obtain a plurality of target hydraulic boundary conditions.

[0267] A second construction unit for constructing a frequency-domain equation for transient flow in a pressurized pipe network according to a pipe network incidence matrix, a hyperbolic function vector of pipe segments, an impedance vector of pipe segments, and a plurality of target hydraulic boundary conditions.

[0268] In some alternative embodiments, the solving module 506 includes:

[0269] A third solving sub-module for solving the frequency-domain equation for transient flow in a pressurized pipe network to obtain a frequency-domain result of transient flow in a pressurized pipe network.

[0270] A conversion sub-module for performing time-domain conversion on the frequency-domain structure of transient flow in a pressurized pipe network to obtain a time series of pressure changes of transient flow during pipe burst in a pressurized pipe network.

[0271] The further function descriptions of the above-mentioned various modules and units are the same as those in the corresponding embodiments above, and will not be elaborated here.

[0272] The device for determining the transient flow pressure state during pipe burst in a pressurized pipe network in this embodiment is presented in the form of functional units. Here, the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and a memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0273] The embodiment of the present invention also provides a computer device having the above Figure 5 shown device for determining the transient flow pressure state during pipe burst in a pressurized pipe network.

[0274] Please refer to Figure 6 , Figure 6 which is a schematic structural diagram of a computer device provided by an alternative embodiment of the present invention. As shown in Figure 6As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting the components, including a high-speed interface and a low-speed interface. Each component communicates with each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in the memory or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some alternative embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories. Similarly, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a set of blade servers, or a multi-processor system). Figure 6 In [the figure], a processor 10 is taken as an example.

[0275] The processor 10 can be a central processing unit, a network processor, or a combination thereof. Among them, the processor 10 can further include a hardware chip. The above-mentioned hardware chip can be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The above-mentioned programmable logic device can be a complex programmable logic device, a field programmable gate array, a generic array logic, or any combination thereof.

[0276] Among them, the memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiments.

[0277] The memory 20 can include a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of the computer device, etc. In addition, the memory 20 can include a high-speed random access memory, and can also include a non-transitory memory, such as at least one disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some alternative embodiments, the memory 20 can optionally include a memory remotely set relative to the processor 10, and these remote memories can be connected to the computer device through a network. Examples of the above-mentioned network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

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

[0279] The computer device further includes a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0280] Embodiments of the present invention also provide a computer-readable storage medium. The method according to the embodiments of the present invention can be implemented in hardware, firmware, or be implemented as computer code that can be recorded on a storage medium, or be implemented as computer code that is originally stored in a remote storage medium or a non-transitory machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored as such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, 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 drive, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or 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] A part of the present invention can be applied as a computer program product, such as computer program instructions. When executed by a computer, through the operation of the computer, the method and / or technical solution according to the present invention can be called or provided. Those skilled in the art should understand that the forms of existence of computer program instructions in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Herein, 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 invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for determining the transient flow pressure state of a pressurized pipe network during pipe burst, characterized in that, The method includes: Obtaining a pipe network parameter set of a pressurized pipe network system, a time period and a time interval of a pipe burst event to be simulated, where the pipe network parameter set includes a plurality of pipe parameters, a plurality of fixed-flow node parameters, a plurality of fixed-pressure node parameters, and a plurality of orifice outflow node parameters; Calculating the Laplace frequency-domain variable of the pipe burst event to be simulated according to the time period and the time interval; Constructing initial hydraulic boundary conditions of each node in the pipe burst event to be simulated according to the pipe network parameter set; Performing steady-state hydraulic simulations before and after the pipe burst respectively 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 section steady-state vectors, and a plurality of second pipe section steady-state vectors after the pipe burst; Constructing a transient flow frequency-domain equation 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 section steady-state vectors, and the plurality of second pipe section steady-state vectors; Solving the transient flow frequency-domain equation of the pressurized pipe network and determining a time series of transient flow pressure changes in the pressurized pipe network burst, where the time series of transient flow pressure changes in the pressurized pipe network burst is used to reflect the transient flow pressure change state of the pressurized pipe network burst.

2. The method according to claim 1, characterized in that, Calculating the Laplace frequency-domain variable of the pipe burst event to be simulated according to the time period and the time interval, including: Calculating the length of the pressure simulation result sequence of each node of the pressurized pipe network according to the time period and the time interval; Determining the time series of the pipe burst event to be simulated according to the length of the pressure simulation result sequence; Calculating the Laplace frequency-domain variable of the pipe burst event to be simulated according to the time series.

3. The method according to claim 1, wherein Performing steady-state hydraulic simulations before and after the pipe burst respectively 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 section steady-state vectors, and a plurality of second pipe section steady-state vectors after the pipe burst, including: Obtaining a first steady-state hydraulic model before the pipe burst and a second steady-state hydraulic model after the pipe burst; Solving 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 section steady-state vectors before the pipe burst; Solving the second steady-state hydraulic model based on the pipe network parameter set to obtain the plurality of second pipe section steady-state vectors after the pipe burst.

4. The method according to claim 1, wherein Constructing a transient flow frequency-domain equation 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 section steady-state vectors, and the plurality of second pipe section steady-state vectors, including: Constructing a pipe network incidence matrix according to the pipe network parameter set; Constructing a pipe section hyperbolic function vector and a pipe section 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 section steady-state vectors, and the plurality of second pipe section steady-state vectors; Constructing the transient flow frequency-domain equation of the pressurized pipe network according to the pipe network incidence matrix, the plurality of hydraulic boundary conditions, the pipe section hyperbolic function vector, and the pipe section impedance vector.

5. The method according to claim 4, characterized in that, Construct the transient flow frequency domain equation of the pressurized pipe network according to the pipe network incidence matrix, the multiple hydraulic boundary conditions, the hyperbolic function vector of the pipe segments, and the impedance vector of the pipe segments, including: Construct a sequence of attenuation exponents; Perform frequency domain conversion on the multiple initial hydraulic boundary conditions by using the sequence of attenuation exponents to obtain multiple target hydraulic boundary conditions; Construct the transient flow frequency domain equation of the pressurized pipe network according to the pipe network incidence matrix, the hyperbolic function vector of the pipe segments, the impedance vector of the pipe segments, and the multiple target hydraulic boundary conditions.

6. The method according to claim 1, wherein Solve the transient flow frequency domain equation of the pressurized pipe network and determine the time series of the transient flow pressure change during pipe burst in the pressurized pipe network, including: Solve the transient flow frequency domain equation of the pressurized pipe network to obtain the transient flow frequency domain result of the pressurized pipe network; Perform time domain conversion on the transient flow frequency domain structure of the pressurized pipe network to obtain the time series of the transient flow pressure change during pipe burst in the pressurized pipe network.

7. A device for determining the transient flow pressure state of a pressurized pipe network burst, characterized in that, The device includes: An acquisition module, configured to acquire a pipe network parameter set of a pressurized pipe network system, a time period and a time interval of a pipe burst event to be simulated, where the pipe network parameter set includes multiple pipe parameters, multiple fixed flow node parameters, multiple fixed pressure node parameters, and multiple orifice outflow node parameters; A calculation module, configured to calculate the Laplace frequency domain variable of the pipe burst event to be simulated according to the time period and the time interval; A first construction module, configured to construct the initial hydraulic boundary conditions of each node in the pipe burst event to be simulated according to the pipe network parameter set; A simulation module, configured to perform steady-state hydraulic simulations before and after pipe burst respectively according to the pipe network parameter set to obtain multiple node steady-state vectors before pipe burst, multiple first pipe segment steady-state vectors, and multiple second pipe segment steady-state vectors after pipe burst; A second construction module, configured to construct the transient flow frequency domain equation of the pressurized pipe network according to the pipe network parameter set, the Laplace frequency domain variable, the multiple hydraulic boundary conditions, the multiple node steady-state vectors, the multiple first pipe segment steady-state vectors, and the multiple second pipe segment steady-state vectors; A solution module, configured to solve the transient flow frequency domain equation of the pressurized pipe network and determine the time series of the transient flow pressure change during pipe burst in the pressurized pipe network, where the time series of the transient flow pressure change during pipe burst in the pressurized pipe network is used to reflect the transient flow pressure change state during pipe burst in the pressurized pipe network.

8. A computer device, characterized in that, Includes: A memory and a processor, which are communicatively connected to each other, where the memory stores computer instructions, and the processor executes the computer instructions to execute the method for determining the transient flow pressure state during pipe burst in the pressurized pipe network according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, Computer instructions are stored on the computer-readable storage medium, and the computer instructions are used to cause a computer to execute the method for determining the transient flow pressure state during pipe burst in the pressurized pipe network according to any one of claims 1 to 6.

10. A computer program product, characterized in that, Includes computer instructions, and the computer instructions are used to cause a computer to execute the method for determining the transient flow pressure state during pipe burst in the pressurized pipe network according to any one of claims 1 to 6.

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