Open channel leakage monitoring method, device, equipment and medium
By deploying water level sensors at key sections of open channels and performing numerical calculations using hydrodynamic models, the upstream and downstream flow relationships can be estimated, solving the problems of low efficiency and large errors in open channel leakage detection and achieving efficient and accurate leakage judgment.
Patent Information
- Application Number
- CN202511630414.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-07
- Publication Date
- 2026-02-06
AI Technical Summary
Existing technologies are insufficient for efficiently and accurately detecting leaks in open channels. They rely mainly on manual inspections and have large measurement errors in flow meters, making them unsuitable for the complexity and turbulent characteristics of water flow in open channels.
By deploying water level sensors at key sections of open channels to acquire real-time water level data and geometric parameters, the Preissmann implicit scheme and Newton-Raphson iterative method are used to solve nonlinear equations, calculate the upstream and downstream flow relationship, and combine a dynamic threshold judgment mechanism to achieve automated judgment of leakage status.
It achieves efficient, accurate, and low-cost automated judgment of open channel leakage status, overcomes the misjudgment problem caused by water flow lag, improves judgment accuracy and environmental adaptability, and reduces system cost.
Smart Images
Figure CN121479098A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to computer technology, in particular to a kind of open channel leakage monitoring method, device, equipment and medium. BACKGROUND
[0002] As a common water conveyance facility, open channel is widely used in irrigation, water supply and other fields. Due to material aging, foundation settlement and other reasons, open channel is prone to leakage, resulting in waste of water resources and engineering safety hazards.
[0003] Currently, leakage detection techniques are mostly for pipeline systems, using pressure sensors, acoustic detection and other methods. However, these methods are developed based on the pressure flow characteristics of pipelines and cannot be directly applied to open channels. Open channel flow is a free flow with a free water surface, and is influenced by factors such as cross-section shape and flow pattern, making the flow pattern complex and variable. In actual engineering, leakage is mainly detected by manual inspection, which is inefficient and unreliable. Although flow meters are sometimes used for monitoring, the complex flow in open channels, especially in areas such as gates and bends where turbulence is strong, results in large measurement errors and makes it difficult to accurately identify leakage. SUMMARY
[0004] Therefore, the purpose of the present application is to provide an open channel leakage monitoring method, device, equipment and medium, which can efficiently, accurately and cost-effectively automatically determine the leakage state of an open channel. The specific scheme is as follows:
[0005] In a first aspect, the present application discloses an open channel leakage monitoring method, comprising:
[0006] obtaining real-time water level data and geometric parameters of a target open channel; the real-time water level data includes instantaneous water level of a first cross-section and instantaneous water level of a second cross-section; the geometric parameters include cross-section shape, channel bottom slope and roughness;
[0007] determining the initial control equation corresponding to the target open channel based on the real-time water level data and the geometric parameters, discretizing the initial control equation according to the Preissmann implicit format to obtain a corresponding nonlinear equation system, and solving the nonlinear equation system based on the Newton-Raphson iteration method to obtain a target control equation;
[0008] determining the first instantaneous flow of the first cross-section at a first time and the second instantaneous flow of the second cross-section at a second time based on the target control equation, the instantaneous water level of the first cross-section and the instantaneous water level of the second cross-section;
[0009] comparing the absolute deviation between the first instantaneous flow and the second instantaneous flow with a preset threshold, and determining whether the target open channel has leaked according to the corresponding comparison result.
[0010] Optionally, the real-time water level data and the geometric parameters of the target open channel are acquired, comprising:
[0011] installing water level sensors to a first cross section and a second cross section of the target open channel respectively to collect real-time water level data based on the water level sensors; the first cross section is a control cross section located upstream of the target open channel; the second cross section is a control cross section located downstream of the target open channel;
[0012] receiving the real-time water level data sent by the water level sensors through cables or wirelessly, and determining the geometric parameters of the target open channel.
[0013] Optionally, the initial control equation corresponding to the target open channel is determined based on the real-time water level data and the geometric parameters, comprising:
[0014] a friction slope is determined based on the roughness through a friction slope calculation formula; the friction slope calculation formula is:
[0015] ;
[0016] wherein, Sf is the friction slope; n is the roughness; A is the water cross section area; Q is the flow; R is the hydraulic radius;
[0017] the initial control equation corresponding to the target open channel is determined based on the real-time water level data, the geometric parameters and the friction slope; the initial control equation is:
[0018] ;
[0019] ;
[0020] wherein, A is the water cross section area; Q is the flow; t is the time; x is the flow process; g is the gravity acceleration; h is the water level; S0 is the channel bottom slope; Sf is the friction slope.
[0021] Optionally, the initial control equation is discretized according to the Preissmann implicit format to obtain a corresponding nonlinear equation group, and the nonlinear equation group is solved based on the Newton-Raphson iteration method to obtain a target control equation, comprising:
[0022] the target open channel is discretized in space into a plurality of calculation cross sections, and a time step is determined;
[0023] the initial control equation is discretized on each of the calculation cross sections and the time step to obtain a corresponding nonlinear equation group;
[0024] the nonlinear equation group is solved based on the Newton-Raphson iteration method until the solution converges to obtain a target control equation.
[0025] Optionally, the determining the first instantaneous flow at the first time of the first section and the second instantaneous flow at the second time of the second section based on the target control equation, the instantaneous water level of the first section and the instantaneous water level of the second section comprises:
[0026] solving the target control equation based on the instantaneous water level of the first section to obtain the first instantaneous flow at the first time of the first section;
[0027] determining a target flow velocity based on a ratio between the first instantaneous flow and the water passage section area;
[0028] determining a distance between the first section and the second section, and determining a flow propagation time based on a ratio between the target flow velocity and the distance;
[0029] determining the second time by summing the flow propagation time and the first time;
[0030] determining a target instantaneous water level of the second section at the second time;
[0031] solving the target control equation based on the target instantaneous water level to obtain the second instantaneous flow at the second time of the second section.
[0032] Optionally, before the comparing the absolute deviation between the first instantaneous flow and the second instantaneous flow with the preset threshold, the method further comprises:
[0033] determining a target product between a standard deviation of flow deviation under the same water level in a historical time period and a preset statistical confidence coefficient, and determining the preset threshold based on a sum between a mean value of flow deviation under the same water level in the historical time period and the target product;
[0034] or, determining the preset threshold according to a percentage of a theoretical flow value.
[0035] Optionally, the comparing the absolute deviation between the first instantaneous flow and the second instantaneous flow with the preset threshold, and determining whether the target open channel has leakage according to a corresponding comparison result comprises:
[0036] determining each absolute deviation between each of the first instantaneous flow and the corresponding second instantaneous flow based on a preset data acquisition frequency;
[0037] determining a continuous number of times that each of the absolute deviations is greater than the preset threshold;
[0038] if the continuous number of times is greater than a target number of times, determining that the target open channel has leakage;
[0039] Otherwise, it is determined that the target open channel does not leak.
[0040] In a second aspect, the present application discloses an open channel leakage monitoring device, comprising:
[0041] a data and parameter acquisition module, configured to acquire real-time water level data and geometric parameters of the target open channel; the real-time water level data comprises instantaneous water levels of the first section and the second section; the geometric parameters comprise a section shape, a channel bottom slope and a roughness;
[0042] a target control equation acquisition module, configured to determine an initial control equation corresponding to the target open channel based on the real-time water level data and the geometric parameters, discretize the initial control equation according to a Preissmann implicit format to obtain a corresponding nonlinear equation group, and solve the nonlinear equation group based on a Newton-Raphson iteration method to obtain a target control equation;
[0043] an instantaneous flow rate determination module, configured to determine a first instantaneous flow rate of the first section at a first time and a second instantaneous flow rate of the second section at a second time based on the target control equation, the instantaneous water levels of the first section and the second section;
[0044] a judgment module, configured to compare an absolute deviation between the first instantaneous flow rate and the second instantaneous flow rate with a preset threshold, and determine whether the target open channel leaks according to a corresponding comparison result.
[0045] In a third aspect, the present application discloses an electronic device, comprising:
[0046] a memory, configured to store a computer program;
[0047] a processor, configured to execute the computer program to implement the open channel leakage monitoring method as described above.
[0048] In a fourth aspect, the present application discloses a computer readable storage medium, and the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the open channel leakage monitoring method as described above.
[0049] The application firstly acquires real-time water level data and geometric parameters of the target open channel; the real-time water level data includes instantaneous water levels of a first section and a second section; the geometric parameters include a section shape, a channel bottom slope and a roughness; an initial control equation corresponding to the target open channel is determined based on the real-time water level data and the geometric parameters, the initial control equation is discretized according to a Preissmann implicit format to obtain a corresponding nonlinear equation group, and the nonlinear equation group is solved based on a Newton-Raphson iteration method to obtain a target control equation; a first instantaneous flow of the first section at a first time and a second instantaneous flow of the second section at a second time are determined based on the target control equation, the instantaneous water levels of the first section and the second section; and finally, an absolute deviation between the first instantaneous flow and the second instantaneous flow is compared with a preset threshold, and whether the target open channel leaks is determined according to a corresponding comparison result. It can be seen that, in the application, water level data is acquired by arranging water level sensors at key sections of the open channel, geometric parameters of the open channel are combined, and numerical calculation is performed by using a control equation. The corresponding relationship between the flows of the upstream and downstream sections at the same time is calculated by the control equation, so that the real-time flow value is indirectly and accurately obtained. Finally, a flow deviation threshold judgment mechanism is established, and efficient, accurate and low-cost automatic judgment of the leakage state of the open channel is realized. In this way, by using the water level parameter which is easy to accurately measure and is less affected by the turbulence of the open channel as the monitoring basis, the problem of large error in directly measuring the flow in the complex open channel flow field is effectively avoided, and reliable data source is provided for the leakage judgment. The time lag effect of the water flow is simulated and compensated by using the hydrodynamic model (control equation) for numerical calculation, the accurate comparison of the upstream and downstream flows at the correct time point in the physical sense is realized, and the misjudgment problem caused by the lag of water flow propagation is solved. The dynamic threshold judgment mechanism is adopted, the threshold value can be adaptively adjusted according to the historical operation data or the real-time hydraulic condition, the defect of poor adaptability of the fixed threshold value in the open channel flow change scene is overcome, and the judgment accuracy and environmental adaptability are significantly improved. BRIEF DESCRIPTION OF DRAWINGS
[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on the provided drawings.
[0051] Figure 1 A flow chart of an open channel leakage monitoring method disclosed by the present application is shown in the figure;
[0052] Figure 2 A flow chart of a specific open channel leakage monitoring method disclosed by the present application is shown in the figure;
[0053] Figure 3 A structure diagram of a open channel leakage monitoring device is disclosed in the present application.
[0054] Figure 4 An electronic device structure diagram is disclosed in the present application. DETAILED DESCRIPTION
[0055] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.
[0056] In some current technologies, the technical core relies on stable and closed pressure flow field to ensure the accuracy of ultrasonic velocity measurement. The characteristics of non-pressure flow, turbulent flow and unsteady flow in the open channel lead to extremely uneven flow distribution, resulting in significant errors in ultrasonic flow measurement based on the time difference method, and low data reliability. Water flow in the pipeline is transmitted rapidly, and the lag effect can be ignored. However, the water conveying distance in the open channel is long, and the change of upstream flow needs a certain time to be reflected in the downstream section. The existing technology directly compares the difference of instantaneous flow, without considering the time lag effect, which is easy to misjudge the normal water flow evolution process as leakage in the open channel. In order to realize accurate measurement, high-precision ultrasonic transducers and high-speed data acquisition cards are required, which is high in equipment cost. The open channel has a harsh field environment, which puts high requirements on the reliability, durability and maintenance cost of the equipment, and it is difficult to be deployed on a large scale. In order to solve the above technical problems, the present application discloses an open channel leakage monitoring method, device, equipment and medium, which can realize efficient, accurate and low-cost automatic judgment of the open channel leakage state.
[0057] Referring to Figure 1 The embodiments of the present application disclose an open channel leakage monitoring method, which comprises:
[0058] Step S11, acquiring real-time water level data and geometric parameters of the target open channel; the real-time water level data comprises instantaneous water level of the first section and instantaneous water level of the second section; the geometric parameters comprise section shape, channel bottom slope and roughness.
[0059] In this embodiment, first, water level sensors are installed to the first section and the second section of the target open channel respectively to collect real-time water level data based on the water level sensors; the first section is a control section located upstream of the target open channel; the second section is a control section located downstream of the target open channel; real-time water level data sent by the water level sensors through a cable or a wireless way is received, and the geometric parameters of the target open channel are determined. The two sections should be selected in a relatively stable channel section. The sensors transmit the collected water level signals (Ha, Hb) to the data collector through a cable or a wireless way. After the data collector preliminarily processes the signals, the signals are sent to the data processing center through a communication network (such as 4G / 5G, LoRa). Then, the computing program deployed on the server or the cloud receives the real-time water level data (such as the instantaneous water level of the upper section Ha(t) and the instantaneous water level of the lower section Hb(t+Δt)) and the geometric parameters (section shape, channel bottom slope S0, roughness n (which is an important index in the calculation of hydraulics and represents the size of the resistance of the channel wall to water flow) and the like) from the data collector. The open channel refers to an open water flow channel, which is commonly used in water conservancy projects such as irrigation channels and drainage ditches.
[0060] In step S12, the initial control equation corresponding to the target open channel is determined based on the real-time water level data and the geometric parameters, the initial control equation is discretized according to the Preissmann implicit format to obtain a corresponding nonlinear equation group, and the nonlinear equation group is solved based on the Newton-Raphson iteration method to obtain a target control equation.
[0061] In this embodiment, the friction slope is determined based on the roughness through a friction slope calculation formula; the friction slope calculation formula is:
[0062] ;
[0063] Wherein, Sf is the friction slope; n is the roughness; A is the water section area; Q is the flow; R is the hydraulic radius;
[0064] The initial control equation corresponding to the target open channel is determined based on the real-time water level data, the geometric parameters and the friction slope; the initial control equation is:
[0065] ;
[0066] ;
[0067] Wherein, A is the water section area; Q is the flow; t is the time; x is the flow process; g is the gravity acceleration; h is the water level; S0 is the channel bottom slope; Sf is the friction slope.
[0068] Then, the target open channel is discretized in space into a plurality of calculation sections, and a time step is determined; the initial control equation is discretized on each of the calculation sections and the time step to obtain a corresponding nonlinear equation set; the nonlinear equation set is solved based on a Newton-Raphson iteration method until the solution converges to obtain a target control equation. Specifically, the control equation in the present application is the Saint-Venant equation set. Therefore, the basic control equation of one-dimensional open channel unsteady flow includes a continuity equation and a momentum equation (Saint-Venant equation set):
[0069] Continuity equation: ;
[0070] Momentum equation: ;
[0071] where A is the water cross-section area; Q is the flow rate; t is the time; x is the flow process; g is the gravitational acceleration; h is the water level; S0 is the channel bottom slope; Sf is the friction slope, which is calculated using the Manning formula: where n is the Manning roughness coefficient, and R is the hydraulic radius.
[0072] Then, the control equation is discretized using the Preissmann implicit scheme. This scheme has the characteristics of good numerical stability and is suitable for unsteady flow calculation. The channel is discretized in space into a plurality of calculation sections, and a time step is divided in time. The continuity equation and the momentum equation are discretized on each calculation unit and time step to form a nonlinear algebraic equation set about unknown quantities (water level h and flow rate Q). The Newton-Raphson iteration method is used to solve the nonlinear equation set until the solution converges, and finally the target control equation is obtained.
[0073] Step S13, determining the first instantaneous flow rate of the first section at the first time and the second instantaneous flow rate of the second section at the second time based on the target control equation, the instantaneous water level of the first section, and the instantaneous water level of the second section.
[0074] In the present embodiment, the target control equation is solved based on the instantaneous water level of the first section to obtain the first instantaneous flow rate of the first section at the first time; the target flow rate is determined based on the ratio between the first instantaneous flow rate and the water cross-section area; the distance between the first section and the second section is determined, and the water flow propagation time is determined according to the ratio between the target flow rate and the distance; the second time is determined through the sum of the water flow propagation time and the first time; the target instantaneous water level of the second section at the second time is determined; and the target control equation is solved based on the target instantaneous water level to obtain the second instantaneous flow rate of the second section at the second time.
[0075] In this process, first, the initial and boundary conditions are set: the measured water level of upstream section A at T1 time Ha(T1) is taken as the upstream boundary condition of the model. The measured water level of downstream section B Hb(t) is taken as the downstream boundary condition. Then, the instantaneous flow Q1 is simulated: based on the boundary conditions at T1 time, the model directly calculates the instantaneous flow Q1 of upstream section A at T1 time by solving the Saint-Venant equation set. After that, the dynamic calculation of flow propagation time Δt: in the forward simulation process of the model, the time Δt required for the water flow to propagate from section A to section B is calculated. The Δt is dynamically determined by the current hydraulic conditions (flow, water level, channel geometric characteristics), which reflects the propagation characteristics of the dynamic wave, and its calculation accuracy is much better than the simple static estimation of "distance / average flow rate". In the process of calculating the flow propagation time Δt, the hysteresis of the water flow is considered. The traditional monitoring flow is to collect the data of A and B points at the same time. Since the channel is a long distance water conveyance, the water flow propagation time is tens of minutes or even several hours. If the upstream section A flow decreases, the B point flow will change several tens of minutes or even several hours later. If the traditional difference value is calculated by collecting data through the flowmeter, it will be misjudged. However, the application can calculate the flow and flow rate through the water dynamics based on the collected water level, and calculate the time (Δt) of the water flow from A to B by dividing the distance between A and B by the flow rate. That is to say, the data collected at A and B sections for calculating whether there is leakage is not at the same time, and the historical library needs to be read through the calculation of the water flow propagation time, and the flow difference is compared. Finally, the corresponding time is determined and Q2 is calculated: the model calculates the flow Q2 of the downstream section B at the corresponding time T2=T1+Δt (the flow and flow rate can be calculated through the collected water level, and the time (Δt) of the water flow from A to B is calculated by dividing the distance between A and B by the flow rate). This Q2 is physically the flow value that the water flow (flow Q1) from section A at T1 time should exhibit after Δt time reaches section B. Further, the flow pair (Q1, Q2) is strictly related in hydrodynamics and has accurately eliminated the time lag effect. Q2 corresponds to T2 time, but Q1 at T1 time originates from the same water flow, providing a synchronous and reliable comparison basis for leakage judgment. In summary, the application solves the one-dimensional Saint-Venant equation set to simulate the whole process of unsteady flow in open channels. The model takes the upstream and downstream of the channel as a whole hydraulic system, and naturally and inherently simulates the dynamic process and time required for the water flow to propagate from the upstream section to the downstream section while calculating the section flow. In this way, the open channel hydrodynamic model (such as the Saint-Venant equation set) is used as a calculation engine to convert water level data into reliable flow data, and the calculation process fully considers the unsteady, time-lagging and turbulent characteristics of the open channel flow.
[0076] Step S14, comparing the absolute deviation between the first instantaneous flow and the second instantaneous flow with a preset threshold value, and judging whether the target open channel leaks according to the corresponding comparison result.
[0077] In this embodiment, before comparing the absolute deviation between the first instantaneous flow and the second instantaneous flow with a preset threshold value, the target product between the standard deviation of the flow deviation under the same water level in the historical time period and the preset statistical confidence coefficient is determined, and the preset threshold value is determined based on the sum between the mean value of the flow deviation under the same water level in the historical time period and the target product; or, the preset threshold value is determined according to the percentage of the theoretical flow value. Specifically, the system continuously stores the flow deviation ΔQ calculated under the no-leakage alarm state and the corresponding working condition information in the past N days (for example, 7 days). Then, the system matches the ΔQ data set under the same or similar working condition from the historical database according to the working condition of the real-time data. Based on the data subset, the mean value μ and the standard deviation σ are calculated. The dynamic threshold value is automatically determined by the formula Q=μ+k*σ. Wherein, k is a preset statistical confidence coefficient. The threshold value can also be set as a percentage (for example, 10%) of the theoretical flow value. In this way, the adaptability to different working conditions is improved.
[0078] Then, each absolute deviation between each first instantaneous flow and the corresponding second instantaneous flow is determined based on the preset data acquisition frequency; the continuous number of times that each absolute deviation is greater than the preset threshold value is determined; if the continuous number of times is greater than a target number of times, it is determined that the target open channel leaks; otherwise, it is determined that the target open channel does not leak. Wherein, the absolute deviation ΔQ(t)=|Q1-Q2| of the flow calculated at the upstream and downstream sections is calculated. ΔQ(t) is compared with the dynamic threshold value Q. If ΔQ(t) continuously exceeds Q for a preset stable number of times T (for example, 5 times in a row, the system is always operating and monitoring, and the calculation of the absolute deviation ΔQ(t) is based on the data acquisition frequency, for example, the system calculates once every 5 minutes if the data is acquired once every 5 minutes), it is determined that the channel segment leaks. Leakage alarm information is generated and sent to the management personnel through the platform interface, short message, email and other ways. If the threshold value is not continuously exceeded, the system will not alarm, which is considered as normal interference at this time. In this way, the dynamic threshold value judgment mechanism is adopted, the threshold value can be automatically adjusted according to the historical operation data or the real-time hydraulic conditions, the defect that the fixed threshold value has poor adaptability in the open channel flow change scene is overcome, and the judgment accuracy and environmental adaptability are significantly improved. Moreover, this technical path does not need to rely on high-cost precise flow monitoring equipment, only needs to lay ordinary water level sensors and combine with the back-end model algorithm to realize, significantly reduces the system cost and maintenance difficulty, and is conducive to large-scale application and promotion.
[0079] It can be seen that, by arranging water level sensors at key sections of the open channel to obtain water level data, combining the geometric parameters of the open channel, and using control equations for numerical calculation, the corresponding relationship between the flow rates of the upstream and downstream sections at the same time is calculated through the control equations, so that the real-time flow rate value is indirectly and accurately obtained. Finally, by establishing a flow rate deviation threshold judgment mechanism, efficient, accurate and low-cost automatic judgment of the leakage state of the open channel is realized. In this way, by using the water level parameter which is easy to accurately measure and less affected by the turbulence of the open channel as the monitoring basis, the problem of large error in directly measuring the flow rate in a complex open channel flow field is effectively avoided, providing a reliable data source for leakage judgment. The use of a hydrodynamic model (control equation) for numerical calculation internally simulates and compensates for the time lag effect of water flow, accurately compares the upstream and downstream flow rates at the correct time point in a physical sense, and solves the problem of misjudgment caused by water flow propagation lag. The dynamic threshold judgment mechanism is adopted, and the threshold value can be adaptively adjusted according to historical operation data or real-time hydraulic conditions, overcoming the poor adaptability of fixed threshold values in the open channel flow change scenario, and significantly improving the judgment accuracy and environmental adaptability.
[0080] The architecture of the open channel leakage monitoring system of the present application mainly includes three modules: a water level data acquisition module, a data processing and flow rate calculation module, and a leakage judgment and output module. The core process diagram is as shown in Figure 2
[0081] First, the water level data acquisition module: including at least two water level sensors and a data collector. The water level sensors are fixedly installed at the upstream reference section (A) and the downstream control section (B) of the open channel respectively. These two sections should be selected in the channel section with relatively stable flow state. The sensors transmit the collected water level signals (Ha, Hb) to the data collector through cables or wireless means. After the data collector performs preliminary processing on the signals, the signals are sent to the data processing center through a communication network (such as 4G / 5G, LoRa).
[0082] The data processing and flow rate calculation module: composition: a calculation program deployed on a server or in the cloud. It receives real-time water level data (such as the instantaneous water level of the upper section Ha(t) and the instantaneous water level of the lower section Hb(t+Δt)) from the data collector and the geometric parameters of the open channel (section shape, channel bottom slope S0, roughness n, etc.). Then, the model realizes accurate calculation and time synchronization comparison of the upstream and downstream flow rates by using the hydrodynamic model. The model solves the control equation of the open channel unsteady flow by numerical method, restores the complete flow rate process from the water level data, and dynamically calculates the water flow propagation time. Specifically, the basic control equation of one-dimensional open channel unsteady flow includes the continuity equation and the momentum equation (Saint-Venant equation set):
[0083] Continuity equation: ;
[0084] Momentum equation: ;
[0085] where A is the cross-sectional area of water; Q is the flow rate; t is the time; x is the flow process; g is the acceleration of gravity; h is the water level; S0 is the channel bottom slope; Sf is the friction slope, calculated using the Manning formula: where n is the Manning roughness coefficient, and R is the hydraulic radius.
[0086] The Preissmann implicit scheme is used to discretize the control equation. This scheme has good numerical stability and is suitable for non-constant flow calculation. The channel is discretized into several calculation sections in space and time steps in time. The continuity equation and momentum equation are discretized at each calculation unit and time step to form a nonlinear algebraic equation set about the unknown quantities (water level h and flow rate Q). The Newton-Raphson iteration method is used to solve the nonlinear equation set until the solution converges, and the target control equation is finally obtained.
[0087] When using the model to calculate, the measured water level Ha(T1) of the upstream section A at time T1 is used as the upstream boundary condition of the model. The measured water level Hb(t) of the downstream section B is used as the downstream boundary condition. Based on the boundary conditions at time T1, the Saint-Venant equation set is solved to directly calculate the instantaneous flow rate Q1 of the upstream section A at time T1. In the forward simulation process of the model, the time Δt required for the water flow to propagate from section A to section B is calculated. This Δt is dynamically determined by the current hydraulic conditions (flow rate, water level, channel geometric characteristics). The model calculates the flow rate Q2 of the downstream section B at the corresponding time T2=T1+Δt. This Q2 is physically the flow rate value that the water flow (flow rate Q1) from section A at time T1 should exhibit after Δt time reaches section B. The flow rate pair (Q1, Q2) is obtained, which is strictly related in hydrodynamics and has accurately eliminated the time lag effect.
[0088] Leakage judgment and output module: composition: judgment logic unit and alarm output unit integrated in the data processing program. Calculate the absolute deviation ΔQ(t)=|Q1-Q2| of the upstream and downstream section calculation flow rate. Compare ΔQ(t) with the dynamic threshold value Q. This threshold value is not a fixed value, and can be dynamically updated according to historical normal operation data (such as the mean and variance of the flow rate deviation at the same time and similar water level in the past 7 days), or set to a percentage (such as 10%) of the theoretical flow rate value. If ΔQ(t) continuously exceeds Q for a preset number of times T (for example, 5 times in a row), it is determined that leakage occurs in the section. Leakage alarm information is generated and sent to management personnel through platform interface, SMS, email, etc.
[0089] In this way, the application obtains water level data by arranging water level sensors at key sections of the open channel, combines the geometric parameters of the open channel, and uses a hydrodynamic model for numerical calculation. The model can fully consider the hysteresis effect of water flow propagation, calculate the corresponding relationship between the flow rates of the upstream and downstream sections at the same time, and thus indirectly and accurately obtain the real-time flow rate. Finally, a flow rate deviation threshold judgment mechanism is established to realize efficient, accurate and low-cost automatic judgment of the leakage state of the open channel.
[0090] Referring to Figure 3 As shown in the drawings, the embodiment of the application discloses an open channel leakage monitoring device, which comprises:
[0091] A data and parameter acquisition module 11 is configured to acquire real-time water level data and geometric parameters of a target open channel. The real-time water level data includes instantaneous water levels of a first section and a second section. The geometric parameters include a section shape, a channel bottom slope and a roughness.
[0092] A target control equation acquisition module 12 is configured to determine an initial control equation corresponding to the target open channel based on the real-time water level data and the geometric parameters, discretize the initial control equation according to a Preissmann implicit format to obtain a corresponding nonlinear equation group, and solve the nonlinear equation group based on a Newton-Raphson iteration method to obtain a target control equation.
[0093] An instantaneous flow rate determination module 13 is configured to determine a first instantaneous flow rate of the first section at a first time and a second instantaneous flow rate of the second section at a second time based on the target control equation, the instantaneous water levels of the first section and the second section.
[0094] A judgment module 14 is configured to compare an absolute deviation between the first instantaneous flow rate and the second instantaneous flow rate with a preset threshold, and determine whether the target open channel has leakage according to a corresponding comparison result.
[0095] In some specific embodiments, the data and parameter acquisition module 11 can be specifically configured to install water level sensors to a first section and a second section of the target open channel respectively to acquire real-time water level data based on the water level sensors, the first section is a control section located upstream of the target open channel, the second section is a control section located downstream of the target open channel, and real-time water level data sent by the water level sensors through a cable or a wireless mode is received, and geometric parameters of the target open channel are determined.
[0096] In some specific embodiments, the target control equation acquisition module 12 can be specifically configured to determine a friction slope based on the roughness through a friction slope calculation formula. The friction slope calculation formula is as follows:
[0097] ;
[0098] wherein Sf is the friction slope; n is the roughness; A is the cross-sectional area of flow; Q is the flow rate; and R is the hydraulic radius.
[0099] determine an initial control equation corresponding to the target open channel based on the real-time water level data, the geometric parameters, and the friction slope; the initial control equation is:
[0100] ;
[0101] ;
[0102] wherein A is the cross-sectional area of flow; Q is the flow rate; t is the time; x is the flow process; g is the acceleration of gravity; h is the water level; S0 is the channel bottom slope; and Sf is the friction slope.
[0103] In some specific embodiments, the target control equation acquisition module 12 can be specifically configured to discretize the target open channel in space into a plurality of calculation sections, and determine a time step; discretize the initial control equation on each calculation section and the time step to obtain a corresponding nonlinear equation group; and solve the nonlinear equation group based on the Newton-Raphson iteration method until the solution converges to obtain the target control equation.
[0104] In some specific embodiments, the instantaneous flow rate determination module 13 can be specifically configured to solve the target control equation based on the instantaneous water level of the first section to obtain a first instantaneous flow rate of the first section at a first time; determine a target flow rate based on the ratio between the first instantaneous flow rate and the cross-sectional area of flow; determine the distance between the first section and the second section, and determine a water flow propagation time based on the ratio between the target flow rate and the distance; determine a second time by summing the water flow propagation time and the first time; determine a target instantaneous water level of the second section at the second time; and solve the target control equation based on the target instantaneous water level to obtain a second instantaneous flow rate of the second section at the second time.
[0105] In some specific embodiments, the device can be further configured to determine a target product between the standard deviation of the flow rate deviation at the same water level in the historical time period and a preset statistical confidence coefficient, determine the preset threshold based on the sum between the mean value of the flow rate deviation at the same water level in the historical time period and the target product, or determine the preset threshold according to the percentage of the theoretical flow rate value.
[0106] In some specific embodiments, the determining module 14 can be specifically configured to determine each absolute deviation between each of the first instantaneous flow and the corresponding second instantaneous flow based on a preset data acquisition frequency; determine a continuous number of times that each of the absolute deviations is greater than the preset threshold; if the continuous number of times is greater than a target number of times, determine that the target open channel has occurred leakage; otherwise, determine that the target open channel has not occurred leakage.
[0107] Further, the embodiment of the present application further discloses an electronic device, Figure 4 The electronic device 20 is shown in a structural diagram according to an example embodiment, and the content in the diagram should not be considered as any limitation on the use range of the present application.
[0108] Figure 4 The electronic device 20 is shown in a structural diagram according to an example embodiment, and the content in the diagram should not be considered as any limitation on the use range of the present application.
[0109] In the embodiment, the power supply 23 is configured to provide working voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol followed by the communication interface 24 can be any communication protocol applicable to the technical solution of the present application, which is not limited here; the input and output interface 25 is configured to obtain external input data or output data to the outside, and the specific interface type can be selected according to the specific application needs, which is not limited here.
[0110] In addition, the memory 22 as a carrier of resource storage can be a read-only memory, a random access memory, a magnetic disk or an optical disk, etc., and the resources stored thereon can include an operating system 221, a computer program 222, etc., and the storage mode can be temporary storage or permanent storage.
[0111] The operating system 221 is configured to manage and control each hardware device and the computer program 222 on the electronic device 20, and can be Windows Server, Netware, Unix, Linux, etc. In addition to the computer program capable of completing the open channel leakage monitoring method executed by the electronic device 20 disclosed in any of the preceding embodiments, the computer program 222 can further include a computer program capable of completing other specific work.
[0112] Further, the application also discloses a computer readable storage medium for storing a computer program, wherein the computer program is executed by a processor to realize the open channel leakage monitoring method disclosed above. For the specific steps of the method, refer to the corresponding content disclosed in the foregoing embodiments, which will not be repeated here.
[0113] The various embodiments are described in the specification by progressive stages, and each embodiment focuses on the differences from other embodiments. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts refer to the method part.
[0114] The skilled person can further realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in the above description in general terms. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the application.
[0115] The steps of the method or algorithm described in combination with the embodiments disclosed herein can be directly implemented by hardware, a software module executed by a processor, or a combination of both. The software module can be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
[0116] Finally, it should be noted that, in this document, relationship terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.
[0117] The technical solutions provided by the present application are described in detail above, and the principles and implementation manners of the present application are described by using specific examples. The above description of the examples is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed, and the above description of the content of the specification should not be understood as a limitation on the present application.
Claims
1. A method for monitoring leakage in open channels, characterized in that, include: Acquire real-time water level data and geometric parameters of the target open channel; the real-time water level data includes the instantaneous water level of the first cross-section and the instantaneous water level of the second cross-section; the geometric parameters include the cross-sectional shape, channel bottom slope, and roughness. Based on the real-time water level data and the geometric parameters, the initial control equations corresponding to the target open channel are determined. The initial control equations are discretized according to the Preissmann implicit scheme to obtain the corresponding nonlinear equation set. The nonlinear equation set is solved based on the Newton-Raphson iterative method to obtain the target control equations. Based on the target control equation, the instantaneous water level of the first cross-section and the instantaneous water level of the second cross-section, the first instantaneous flow rate of the first cross-section at the first moment and the second instantaneous flow rate of the second cross-section at the second moment are determined. The absolute deviation between the first instantaneous flow rate and the second instantaneous flow rate is compared with a preset threshold, and the target open channel is judged to have leaked based on the comparison result.
2. The open channel leakage monitoring method according to claim 1, characterized in that, The acquisition of real-time water level data and geometric parameters of the target open channel includes: Water level sensors are installed at the first and second sections of the target open channel to collect real-time water level data; the first section is a control section located upstream of the target open channel; the second section is a control section located downstream of the target open channel. Receive real-time water level data transmitted by the water level sensor via cable or wireless means, and determine the geometric parameters of the target open channel.
3. The open channel leakage monitoring method according to claim 1, characterized in that, The determination of the initial control equations corresponding to the target open channel based on the real-time water level data and the geometric parameters includes: The friction slope is determined based on the roughness using the friction slope calculation formula; the friction slope calculation formula is as follows: ； Where Sf is the friction gradient; n is the roughness coefficient; A is the cross-sectional area of the water passage; Q is the flow rate; and R is the hydraulic radius. Based on the real-time water level data, the geometric parameters, and the friction slope, the initial control equations corresponding to the target open channel are determined; the initial control equations are: ； ； Where A is the cross-sectional area of the water passage; Q is the flow rate; t is the time; x is the flow rate; g is the gravitational acceleration; h is the water level; S0 is the slope of the channel bottom; and Sf is the friction slope.
4. The open channel leakage monitoring method according to claim 1, characterized in that, The initial control equations are discretized according to the Preissmann implicit scheme to obtain the corresponding nonlinear equation system. The nonlinear equation system is then solved using the Newton-Raphson iterative method to obtain the target control equations, including: The target open channel is spatially discretized into several calculation sections, and the time step is determined. The initial control equations are discretized at each of the aforementioned calculation sections and time steps to obtain the corresponding nonlinear equation sets. The nonlinear equations are solved using the Newton-Raphson iterative method until the solution converges, thus obtaining the target governing equations.
5. The open channel leakage monitoring method according to claim 1, characterized in that, The determination of the first instantaneous flow rate at the first cross-section at a first moment and the second instantaneous flow rate at the second cross-section at a second moment based on the target control equation, the instantaneous water level at the first cross-section, and the instantaneous water level at the second cross-section includes: The target control equation is solved based on the instantaneous water level of the first cross-section to obtain the first instantaneous flow rate of the first cross-section at the first moment; The target flow velocity is determined based on the ratio between the first instantaneous flow rate and the cross-sectional area of the water passage; Determine the distance between the first cross-section and the second cross-section, and determine the water flow propagation time based on the ratio between the target flow velocity and the distance; The second moment is determined by the sum of the water flow propagation time and the first moment; Determine the target instantaneous water level at the second cross-section at the second moment; The target control equation is solved based on the target instantaneous water level to obtain the second instantaneous flow rate of the second cross-section at the second time.
6. The open channel leakage monitoring method according to claim 1, characterized in that, Before comparing the absolute deviation between the first instantaneous flow rate and the second instantaneous flow rate with a preset threshold, the method further includes: Determine the target product between the standard deviation of the flow rate deviation at the same water level within a historical time period and a preset statistical confidence coefficient, and determine the preset threshold based on the sum of the mean of the flow rate deviation at the same water level within a historical time period and the target product; Alternatively, the preset threshold can be determined as a percentage of the theoretical flow rate.
7. The method for monitoring leakage in open channels according to any one of claims 1 to 6, characterized in that, The step of comparing the absolute deviation between the first instantaneous flow rate and the second instantaneous flow rate with a preset threshold, and determining whether the target open channel has leaked based on the comparison result, includes: The absolute deviations between each of the first instantaneous flow rates and the corresponding second instantaneous flow rates are determined based on a preset data acquisition frequency. Determine the number of consecutive times that each absolute deviation is greater than the preset threshold; If the number of consecutive occurrences exceeds the target number, then the target open channel is determined to be leaking. Otherwise, it is determined that no leakage has occurred in the target open channel.
8. A leakage monitoring device for open channels, characterized in that, include: The data and parameter acquisition module is used to acquire real-time water level data and geometric parameters of the target open channel; the real-time water level data includes the instantaneous water level of the first cross-section and the instantaneous water level of the second cross-section; the geometric parameters include the cross-sectional shape, channel bottom slope, and roughness. The target control equation acquisition module is used to determine the initial control equation corresponding to the target open channel based on the real-time water level data and the geometric parameters, discretize the initial control equation according to the Preissmann implicit scheme to obtain the corresponding nonlinear equation system, and solve the nonlinear equation system based on the Newton-Raphson iterative method to obtain the target control equation. The instantaneous flow determination module is used to determine the first instantaneous flow rate of the first cross-section at a first moment and the second instantaneous flow rate of the second cross-section at a second moment based on the target control equation, the instantaneous water level of the first cross-section, and the instantaneous water level of the second cross-section. The judgment module is used to compare the absolute deviation between the first instantaneous flow rate and the second instantaneous flow rate with a preset threshold, and to determine whether the target open channel has leaked based on the comparison result.
9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor for executing a computer program to implement the open channel leakage monitoring method as described in any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, A computer-readable storage medium stores a computer program that, when executed by a processor, implements the open channel leakage monitoring method as described in any one of claims 1 to 7.