TWI704314B - A method for constructing partially cut pipe network hydraulic model - Google Patents

Abstract

The present invention relates to a method for constructing partially cut pipe network hydraulic model. It comprises the following steps of connecting a plurality of inlet/outlet nodes of a hydraulic model to a virtual pool; calculating first flow time variation mode of the virtual pool; measuring second flow time variation mode and second pressure time variation mode of a plurality of inlet/outlet nodes of a water supply network and subtracting a leakage flow from the second flow time variation mode to obtain the third flow time variation mode; comparing the first flow time variation mode and the third flow time variation mode for correcting a basic water-using flow and a water-using mode of the hydraulic model; analyzing pressure difference of the hydraulic model for correcting pipe roughness coefficient of the hydraulic model; and analyzing a pressure value of the plurality of nodes of the corrected hydraulic model and an actual measured pressure value to obtain a water leakage point of the water supply network.

Description

A method of constructing partially cut pipe network hydraulic model

The present invention relates to a method for constructing a partially cut hydraulic model of a pipe network, which can simulate the actual pipeline environment of the water supply pipe network, and modify it according to the measured flow time change pattern and pressure time change pattern of the water supply pipe network The environmental parameters of the hydraulic model are used to predict the location of water leakage in the water supply network.

According to statistics, the global average leakage rate is 35%, so how to effectively reduce the leakage rate has become an important issue for the water supply industry in the 21st century. In this regard, the International Water Association (IWA) proposed a complete set of water supply pipeline network leakage control strategies. According to the leakage control strategy, the large-scale water supply pipeline network can be cut into many metering zones, which is called District Metered DMA (District Metered Area), and install a flow meter at the water inlet, estimate the amount of water leakage through the difference between the flow meter at the water inlet and the water meter of all users, and find the leakage point of the water supply pipe network.

Chinese Patent Announcement No. CN 107355688 "A LeakView urban water supply pipe network leakage control management system", which forms the water supply pipe network into a first-level partition, a second-level partition, DMA, and a user-end multi-level water unit partition management mode. Each water unit passes water The balance test is scientifically managed, and the pressure response mechanism of the leakage of the water supply pipe network is used to formulate a pressure regulation strategy with the best water-saving effect and economic matching. On-line monitoring of leakage and noise uses terminal noise monitoring equipment to replace artificial hearing leakage, and the noise is used as data Through the comparison and analysis of key data, the suspected missing areas are found.

The previous patent is mainly to provide proper water pressure when the pipe network leakage is found, so that the user has enough water to use. However, the judgment of the leakage point is based on the noise analysis and the monitoring equipment for the leakage operation. It needs to be additionally installed in the pipe network to collect the noise data of each pipeline. The equipment will increase the overall cost, and the noise will be easily affected by the environment and lose the accuracy of the analysis.

Today, the inventor is based on the fact that the above-mentioned existing pipe network leakage analysis method still has many shortcomings in actual implementation and use, so it is a tireless spirit, supplemented by his rich professional knowledge and years of practical experience, and Improve, and develop the present invention accordingly.

The main purpose of the present invention is to provide a partially cut pipe network hydraulic model construction method, which constructs the water supply pipe network into a hydraulic model through the principle of fluid mechanics, and compares the water supply pipe network's flow and pressure time change pattern with the hydraulic model The time change mode of flow and pressure is used to modify the simulation parameters of the hydraulic model to simulate the leakage position of the water supply network.

In order to achieve the above-mentioned implementation objectives, the present invention is a method for constructing a partially cut pipe network hydraulic model. The analysis method is to establish a hydraulic model from a partially cut water supply pipe network (such as DMA), and connect a plurality of water inlet/outlet nodes of the hydraulic model A virtual pool; the simulation analysis of the hydraulic model is carried out with the preset model parameters, and the first flow time change mode of one of the inlet/outlet ports of the virtual pool is calculated; one of the plural inlet/outlet nodes of the water supply pipe network is measured or predicted The second flow time change mode and the second pressure time change mode, the second flow time change mode is subtracted from the water leakage flow of the water supply pipe network to obtain a third flow time change mode; the first flow time change mode and the third flow time The change mode is compared to modify a plurality of basic water flow rates and a water mode preset by the hydraulic model; the pressure difference analysis is performed on a plurality of nodes of the hydraulic model to modify a pipeline roughness coefficient preset by the hydraulic model; and Hydraulic model Model, simulates the pressure values of multiple nodes and analyzes and compares them with the actual pressure values to obtain the water leakage point of the water supply pipe network, and calculate the fourth flow rate of one of the outlets of the virtual pool according to the hydraulic model after the correction in step 6 Time change mode; wherein according to the second flow time change mode and the fourth flow time change mode, in conjunction with the second pressure time change mode, the water leakage sensitivity N1 can be obtained by analysis.

In an embodiment of the present invention, the preset model parameters are a plurality of basic water flow rates, water usage patterns, pipeline sizes, pipeline roughness coefficients, and operating equipment parameters and operating conditions.

In an embodiment of the present invention, the water supply pipe network has a plurality of nodes, a plurality of water inlet/outlet nodes, and a plurality of flow meters or pressure gauges arranged at the plurality of water inlet/outlet nodes.

In an embodiment of the present invention, the second flow rate time change mode and the second pressure time change mode are obtained by a plurality of flow meters and pressure measurement.

In one embodiment of the present invention, through machine learning, time series models, or flowmeters or pressure gauges installed at a plurality of water inlet/outlet nodes, the time variation mode of the virtual pool pressure of the hydraulic model is predicted or measured.

In an embodiment of the present invention, the second flow rate time variation mode can be obtained by calculation through a time series model or a neural network prediction model.

In one embodiment of the present invention, the hydraulic model system can further analyze the water age distribution and water age indicators of the water supply pipe network.

In one embodiment of the present invention, the virtual pool connected to a plurality of water inlet/outlet nodes in the hydraulic model can be replaced by a virtual water pump or a virtual water node; wherein the virtual water pump is installed by the flow rate of an inlet node Obtain the flow and pressure relationship curve of the virtual pump based on the data of the meter and pressure measurement, and then use the flow and pressure relationship curve to simulate the pipe network; the virtual water node is measured by a flow meter installed at an outlet node Data, obtain the water flow time change curve of the virtual water node, and then The pipe network is simulated based on the time change curve of the water flow.

In one embodiment of the present invention, two modified and adjacent hydraulic models are replaced with a connecting node for the virtual pool, virtual water pump or virtual water use node on the boundary, and the two modified hydraulic models are replaced by the connecting node. The pipeline connection.

(1): Water supply network

(11): Leakage point

(2): Hydraulic model

(3): Water inlet/outlet node

(4): Node

Figure 1: A schematic diagram of the water supply pipe network of the preferred embodiment of the present invention.

Figure 2: A schematic diagram of a large-scale pipe network hydraulic model of the preferred embodiment of the present invention.

Figure 3: A diagram of the regional pipe network cut out of the large pipe network of the preferred embodiment of the present invention.

Figure 4: A diagram of the preset water consumption mode of the preferred embodiment of the present invention.

Figure 5: Time change diagram of the water inlet/outlet flow of the virtual pool of the water supply pipe network in the preferred embodiment of the present invention.

Figure 6: Time change diagram of the water inlet/outlet pressure of the virtual pool of the water supply pipe network in the preferred embodiment of the present invention.

Figure 7: Modified water mode diagram of the preferred embodiment of the present invention.

Figure 8: The water age analysis double inlet/outlet node pipe network diagram of the preferred embodiment of the present invention.

Figure ninth: a comparison diagram of the node pressure difference of the preferred embodiment of the present invention.

Figure 10: Comparison of node water age in the preferred embodiment of the present invention.

The purpose of the present invention and its structural and functional advantages will be described based on the structure shown in the following drawings and specific embodiments, so that the review committee can have a deeper and specific understanding of the present invention.

Please refer to the first figure. A method for constructing a partially cut pipe network hydraulic model (the third figure) of the present invention includes step one: establish a hydraulic model (2) from the partially cut water supply pipe network (1), and combine the hydraulic Multiple water inlet/outlet nodes (3) of model (2) are connected to a virtual water Pool; Step 2: Use the preset model parameters to simulate the hydraulic model (2) by setting multiple basic water flow rates, water usage patterns, pipeline sizes, pipeline roughness coefficients, and operating equipment parameters and operating conditions Analyze and calculate the first flow time change pattern of one of the water inlets/outlets of the virtual pool. The basic water flow is calculated by multiplying the average hourly water consumption of each user by the total number of users. The water consumption mode refers to multiple nodes (4). The flow rate changes over time; Step 3: Measure or predict a second flow rate time change mode and a second pressure time change mode of a plurality of water inlet/outlet nodes (3) of the water supply pipe network (1), and set The flow time change mode subtracts the leakage flow of the water supply pipe network (1) to obtain a third flow time change mode; Step 4: Compare the first flow time change mode with the third flow time change mode to modify the hydraulic model (2 ) Pre-set multiple basic water flow rates and a water use mode; Step 5: Perform pressure difference analysis on multiple nodes (4) of the hydraulic model (2) to correct a preset pipeline roughness coefficient of the hydraulic model (2); And step 6: According to the revised hydraulic model (2), the pressure values of multiple nodes (4) are simulated and compared with the measured pressure values to obtain the water leakage point (11) of the water supply network (1).

Then according to the revised hydraulic model in step 6, calculate the fourth flow time change mode of one of the virtual water inlet/outlet of the virtual pool. The second flow time change mode and the fourth flow time change mode are matched with the second pressure time change mode. The system can analyze the water leakage sensitivity, which is an important indicator of water pressure management in the water supply network (1); and this hydraulic model (2) can also further analyze the water age distribution of the water supply network (1).

Among them, the water supply pipe network (1) also has a plurality of flow meters and pressure gauges installed in a plurality of water inlet/outlet nodes (3), and the hydraulic model (2) can be installed in a plurality of The flow meter or pressure gauge of the water inlet/outlet node (3) predicts or measures the time change mode of the virtual pool pressure of the hydraulic model (2).

In addition, in the hydraulic model (2), the virtual pool connected to the multiple water inlet/outlet nodes (3) can be replaced by a virtual water pump or a virtual water node; among them, the virtual water pump is installed The flowmeter and pressure measurement data of a water inlet node are used to obtain the flow and pressure relationship curve of the virtual water pump, and then the flow and pressure relationship curve is used to simulate the pipe network; the virtual water node is installed at an outlet node The data measured by the flowmeter is used to obtain the water flow time change curve of the virtual water use node, and then use the water flow time change curve to simulate the pipe network. In addition, two modified and adjacent hydraulic models (2) can be replaced with a connecting node to replace the virtual pool on the boundary, and the pipelines of the two modified cutting models can be connected by the connecting node.

In addition, the following specific examples can further prove the scope of practical application of the present invention, but it is not intended to limit the scope of the present invention in any form.

Please refer to the first and second figures, where the water supply pipe network (1) can be an area cut out of a large pipe network, and the water supply pipe network (1) with a leaking point (11) is located in the The point E between the node (4) N9 and N5 is the water leakage point (11). The hydraulic model (2) analysis method of the pipe network leakage of the present invention is to find the water leakage point in the water supply pipe network (1) (11); First of all, the third picture is a regional pipe network cut out of a large pipe network, which is based on the hydraulic model (2) to simulate the style of the water supply pipe network (1), because the location of the leaking point (11) is not known , So the figure does not include the simulation of the water leakage point, where the water inlet/outlet node (3) will be connected to a virtual pool. Through the time series model and machine learning, the pressure gauge can predict or measure the virtual pool pressure of the hydraulic model (2) Time change mode, in conjunction with a plurality of preset basic water flow, water use mode, pipeline size, pipeline roughness coefficient, and operating equipment parameters and operating conditions, perform the hydraulic model (2) simulation of the cut water supply network (1).

When implementing time series statistical analysis, the time series model uses the pressure data of 19 consecutive Mondays to perform polynomial regression analysis, and its correlation coefficient R ² =0.8948, which is quite satisfactory. The regression equation is used to predict the pressure on the 20th Monday. Comparing the data with the actual pressure data on the 20th Monday, the average error of the 20th Monday is only 0.01984% and the standard deviation is only 0.01339%. Refer to Table 1.

The neural network prediction model uses the perceptron neural network to predict the pressure mode. For example, the pressure data of the previous Monday (one per hour, a total of 24) is the input vector, so that the input layer has a total of 24 neurons, and Set the hidden layer to 3 neurons, and the output layer has 24 neurons. The output layer represents the pressure data of the next Monday every hour. The pressure data of 18 consecutive Mondays can be used as the learning data of the neural network. , And then use the pressure data of the 19th Monday as the input vector after completing the neural network learning to predict the pressure data of the 20th Monday. The average error is only 0.03886% and the standard deviation is only 0.0336%. Table 2.

The water consumption mode can be seen in the fourth figure. It can be found that users continue to use water from 6 o'clock every day, and the water consumption starts to decline after 23:00; the basic water flow is calculated by multiplying the average hourly water consumption per household by the number of users. , Assuming that there are 100 users at the water inlet/outlet node 3, and the average daily water consumption per household = 0.8m ³ , the basic water flow is equal to (100*0.8)/24.

Since the parameters of the hydraulic model (2) have not been corrected, the actual flow and pressure changes between it and the water supply pipe network (1) still have errors. In order to correct them one by one, the present invention is divided into four scenarios, scenario A represents the real water supply Pipe network (1), with water leakage points (11); scenario B is the hydraulic model (2) of water supply pipe network (1), without water leakage points (11), basic water consumption, water use pattern, and pipeline roughness coefficients are all It has not been corrected; scenario C is the hydraulic model (2) of the water supply pipe network (1), it has no water leakage point (11), the basic water consumption and water use pattern have been corrected, and the pipeline roughness coefficient has not been corrected; scenario D is the water supply pipe network ( The hydraulic model (2) of 1) has no water leakage point (11). The basic water consumption, water consumption pattern and pipeline roughness coefficient have all been corrected. The following four scenarios are explained separately.

Scenario A: Taking the water supply pipe network (1) in the first figure as the object, it measures or predicts the water supply based on the flowmeter and pressure gauge of the plural water inlet/outlet nodes (3) installed in the water supply pipe network (1) A second flow time change pattern and a second pressure time change pattern of a plurality of water inlet/outlet nodes (3) of the pipe network (1) are shown in the fifth and sixth diagrams.

Scenario B: Scenario B is mainly used to modify the water use pattern. First, scenario A obtains the net flow Q _{Ai at} time i and the water leakage Q _Li at time i, and scenario B obtains the net flow Q _{Bi at} time i , And add up all the flow differences within a 24-hour range (one data every 10 minutes) to obtain the flow deviation value ΔQ between scenario A and scenario B. The calculation process is as follows: Formula 1.

That is, the second flow time change mode is first subtracted from the water leakage flow of the water supply pipe network (1) to obtain a third flow time change mode, and then compare the difference with the second flow time change mode, and then convert the flow deviation value to 24 The total volume deviation within hours (one data every 10 minutes), the total volume deviation is divided by the total number of users, then divided by 24 hours, as the correction coefficient, each node (4) the number of users multiplied by the correction coefficient, get the node ( 4) The basic water flow correction value, plus the basic water flow before the correction of each node (4) in the hydraulic model (2) of scenario B above, the corrected basic water flow of each node (4) can be obtained. The results are shown in the table 3. Divide the third flow time change pattern by the corrected basic water flow to obtain the corrected water use pattern as shown in Figure 7.

Situation C

Correct the basic water consumption and water usage mode according to scenario B, and then continue to correct the pipeline roughness coefficient. Because the pipelines of the same length are at the same flow rate, the pressure loss will be different due to the different pipeline roughness coefficients, so the pressure value of node (4) is used The deviation from the actual pressure value of the water supply network (1) is used to correct the pipeline roughness coefficient. Since scenario A contains leaks (11) and scenario C does not contain leaks (11), it is necessary to correct scenario A before correcting the pipeline roughness coefficient. The pipeline roughness coefficient correction method of the present invention first presets multiple sets of pipeline roughness coefficients (Hazen-Williams Coefficient, HWC), respectively 80, 90, 100, 110, and compares the roughness coefficients of different pipelines. In this case, find the roughness coefficient with the smallest average value of pressure difference △P, that is, analyze the pressure difference of multiple nodes (4) of the hydraulic model (2). The calculation process is shown in formula 2, and the results are shown in Table 4. .

In formula 4, i represents 144 data at different times, and j represents 10 nodes (4).

As shown in Table 4, it can be clearly seen that when the pipeline roughness coefficient HWC is 100, the average pressure difference is the smallest, which represents an optimized pipeline roughness coefficient of 100.

Situation D

After the parameters of Scenario B and Scenario C are corrected, the hydraulic model (2) is the hydraulic model closest to the real pipe network, except that it lacks the simulation of the leakage point. If you want to find the leakage point (11) through the hydraulic model (2) Position, the water leakage Q _{L of} scenario A needs to be deducted, and then the pressure difference measured by each node (4) of the hydraulic model (2) and the water supply network (1) pressure gauge is compared. The node with the largest difference and the most frequent occurrence ( 4), which means that the water leakage point (11) is located upstream of the node (4).

Calculate the pressure value of the pipe network node (4) every 10 minutes within a 24-hour period, select the node (4) with the largest pressure difference calculated each time, and count the node (4) with the most occurrences, which is the downstream position where the water leakage occurs. The results of node (4) are shown in the ninth figure. After statistics, the maximum pressure difference of node (4) N5 appears 143 times, and the maximum pressure difference of node (4) N6 appears once, which represents water leakage Point (11) is located upstream of node (4) N5, which is the water leakage point (11) E between N9 and N5 in the first figure.

Situation E

In order to obtain the water leakage sensitivity, a scenario E is added, a simulated water leakage point (the water leakage point in scenario D) is added to the hydraulic model (2), and its discharge coefficient and pressure exponent are set. .

According to the FAVAD formula of the International Water Association, (L _t1 /L _t2 )=(P _t1 /P _t2 ) ^N1 , to calculate the leakage sensitivity N1, first calculate the difference between the inflow and outflow node flow values of the situation D and the situation E at time t, namely Is the leakage flow rate L _t at time t, and then calculate the average pressure of all nodes (4) in the context E at time t, which is the pipe network pressure value P _t at time t, and calculate L _t and P _t every 10 minutes in a 24-hour range , And then enter the FAVAD formula, you can get 144 N1 values, and the average is the water leakage sensitivity (N1).

Situation F

Furthermore, the parameter-corrected hydraulic model (2) can also be used to analyze the water age of the water supply pipe network (1). According to the water age distribution, whether the location of the water supply pipe network (1) inlet/outlet node (3) is selected appropriately The water age distribution can also be used as an important reference for the implementation of zone metering leakage control technology when cutting the water supply area; the water age index refers to the sum of the average water age of each node (4) of the pipe network within 24 hours, and then Divided by the number of nodes (4), it is the average water age of the overall node (4) of the pipe network. Table 5 shows the calculation results of the water age index of the hydraulic model of the third figure and the eighth figure of the double inlet/outlet node hydraulic model , From Table 5 and Figure 10, it can be seen that the water age distribution of the dual inlet/outlet node hydraulic model is better than that of the hydraulic model.

It can be seen from the above-mentioned implementation description that, compared with the prior art, the present invention Ming has the following advantages:

1. A method of constructing a partially cut pipe network hydraulic model of the present invention is to build a partially cut pipe network into a hydraulic model, and through the parameter correction of the above scenarios B and C, to build a correct simulation environment.

2. A method of constructing a partially cut pipe network hydraulic model of the present invention. After correcting the various parameters of the hydraulic model, the node pressure value of the hydraulic model is analyzed and compared with the measured pressure value through scenario D, and the maximum pressure difference can be found , The location of the leaking point is known.

3. Scenario E of the method for constructing a partially cut pipe network hydraulic model of the present invention proposes an effective method for calculating the 24-hour N1 value using a hydraulic model, which is more reasonable and accurate than the traditional estimation of the N1 value based only on night water leakage.

4. A method of constructing a partially cut pipe network hydraulic model of the present invention proposes a partially cut pipe network hydraulic model to analyze the influence of different inlet/outlet points of the pipe network on the water age distribution, and proposes a water age index as an evaluation criterion.

In summary, the method for constructing a partially cut pipe network hydraulic model of the present invention can indeed achieve the expected use effect through the embodiments disclosed above, and the present invention has not been disclosed before the application. Comply with the provisions and requirements of the Patent Law. If you file an application for a patent for invention in accordance with the law, you are kindly requested to review it and grant a quasi-patent.

However, the above-mentioned illustrations and descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. Those who are familiar with the art will do other things based on the characteristic scope of the present invention. Equivalent changes or modifications should be regarded as not departing from the design scope of the present invention.

(1): Water supply network

(11): Leakage point

(3): Water inlet/outlet node

(4): Node

Claims (9)

A method for constructing a partially cut pipe network hydraulic model. The steps include: Step 1: Build a hydraulic model from the partially cut water supply pipe network, and connect multiple inlet/outlet nodes of the hydraulic model to a virtual pool; Step 2: Carry out the simulation analysis of the hydraulic model with the preset model parameters, and calculate the first flow time change mode of one of the outlets of the virtual pool; Step 3: Measure or predict the water inlet/outlet nodes of the water supply network A second flow time change mode and a second pressure time change mode, the second flow time change mode is subtracted from the water leakage flow of the water supply pipe network to obtain a third flow time change mode; Step 4: The first flow time The change mode is compared with the third flow time change mode to correct the basic water flow and a water use mode preset in the hydraulic model; Step 5: Perform pressure difference analysis on multiple nodes of the hydraulic model to modify the hydraulic model in advance Set a pipeline roughness coefficient; and Step 6: According to the corrected hydraulic model, simulate the pressure values of the multiple nodes and analyze and compare them with the measured pressure values to obtain the water leakage point of the water supply network, and then correct it according to step 6 Then the hydraulic model calculates a fourth flow time change mode of one of the virtual pool outlets; wherein the time change according to the second flow The chemical mode and the fourth flow time change mode, in conjunction with the second pressure time change mode, can analyze and obtain the water leakage sensitivity N1. For example, the method for constructing a partially cut hydraulic model of a pipe network as described in item 1 of the scope of patent application, wherein the preset model parameters are the plurality of basic water flow rates, the water use mode, the pipeline size, the pipeline roughness coefficient and the parameters of the operating equipment And operating conditions. For example, the method for constructing a partially cut hydraulic model of a pipe network described in item 1 of the scope of patent application, wherein the water supply pipe network has the plurality of nodes, the plurality of water inlet/outlet nodes, and the plurality of water inlet/outlet nodes arranged at the plurality of Flow meter or pressure gauge. For example, the method for constructing a partially cut pipe network hydraulic model described in the scope of patent application, wherein the second flow rate time change mode and the second pressure time change mode are obtained by the plurality of flow meters and pressure measurement. For example, the partially cut pipe network hydraulic model construction method described in item 3 of the scope of patent application, through machine learning, time series model, or the flowmeter or pressure gauge installed at multiple water inlet/outlet nodes, predict or measure the Time change mode of virtual pool pressure of hydraulic model. For example, the method for constructing a partially cut hydraulic model of a pipe network described in the scope of the patent application, wherein the second flow rate time change mode can be obtained by calculation through a time series model or a neural network prediction model. For example, the method for constructing a partially cut hydraulic model of a pipe network described in the scope of patent application, wherein the hydraulic model can further analyze the water age distribution and water age indicators of the water supply pipe network. For example, the method for constructing a hydraulic model of a partially cut pipe network described in the scope of the patent application, in which a plurality of virtual pools connected to the water inlet/outlet nodes in the hydraulic model can be replaced by a virtual water pump or a virtual water node; wherein the virtual water pump, The flow rate and pressure relationship curve of the virtual water pump is obtained by the flowmeter installed at a water inlet node and the pressure measurement data, and then the pipeline network simulation is performed with the flow rate and pressure relationship curve; the virtual water node is borrowed From the data measured by the flowmeter installed at a water outlet node, the water flow time change curve of the virtual water node is obtained, and then the water flow time change curve is used to simulate the pipe network. For example, the method for constructing a hydraulic model of a partially cut pipe network as described in item 8 of the scope of patent application, in which two modified and adjacent hydraulic models are replaced with a connecting node for the virtual pool, the virtual water pump, or the virtual water Node, and use the connection node to connect the pipelines of the two revised hydraulic models.

Images