CN112628613A - Method and system for monitoring pipeline leakage, positioning leakage and calculating leakage amount - Google Patents

Method and system for monitoring pipeline leakage, positioning leakage and calculating leakage amount Download PDF

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CN112628613A
CN112628613A CN202011557179.2A CN202011557179A CN112628613A CN 112628613 A CN112628613 A CN 112628613A CN 202011557179 A CN202011557179 A CN 202011557179A CN 112628613 A CN112628613 A CN 112628613A
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pipeline
leakage
pressure
outlet
inlet
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杨保文
韩斌
刘爱国
杨罗娜
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Qingdao Denang Innovation Technology Co Ltd
Acoustic Systems Inc
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17D—PIPE-LINE SYSTEMS; PIPE-LINES
    • F17D5/00—Protection or supervision of installations
    • F17D5/02—Preventing, monitoring, or locating loss
    • F17D5/06—Preventing, monitoring, or locating loss using electric or acoustic means
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    • G06F30/28—Design optimisation, verification or simulation using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/08—Fluids
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/14—Pipes
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces

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Abstract

The invention provides a method for monitoring pipeline leakage, positioning leakage and calculating leakage amount, which comprises the following steps: step 1: acquiring and obtaining the operating parameters of a pipeline to be detected; step 2: establishing a mathematical model to obtain a calculated value of the pipeline parameter on the length of the pipeline; and step 3: comparing the parameter calculation value with the monitoring value; and 4, step 4: after the pipeline is judged to leak, the leaking position is positioned by adopting a negative pressure wave method; and 5: calculating the leakage amount; on the basis of a large number of experiments and CFD verification, the method independently develops a bent pipe hydraulic loss sub-model, a temperature-to-pipe diameter influence sub-model, a reducing-gradually-expanding pipe sub-model, a pressure wave velocity sub-model and the like, breaks the limitation of the three-dimensional pipeline in one-dimensional calculation, and has better calculation accuracy and calculation efficiency. The leakage quantity calculation model which is independently developed is embedded, and the leakage positioning and leakage quantity early warning functions are provided when the pipeline leakage monitoring is carried out.

Description

Method and system for monitoring pipeline leakage, positioning leakage and calculating leakage amount
Technical Field
The invention relates to the technical field of pipeline leakage, in particular to a method and a system for pipeline leakage monitoring, leakage positioning and leakage amount calculation.
Background
Pipeline transportation is combined with waterway transportation, road transportation, railway transportation and air transportation as five transportation modes, and is mainly applied to conveying liquid, gas, slurry and the like. With the rapid development of national economy in China in the last decade, the role of pipeline transportation in economic development is more and more important.
With the increase of pipelines and the extension of the running time of equipment, the pipelines leak due to careless construction, corrosion and erosion, artificial damage and the like. The leakage of the pipeline not only causes huge economic loss, but also causes serious environmental pollution, resource waste and serious safety accidents.
Therefore, how to position the leakage position in time and accurately in pipeline transportation is a crucial role in the safety of pipeline transportation and is also a main task of real-time monitoring, and most of the existing pipeline leakage monitoring technologies can only perform leakage positioning and have large positioning errors.
Disclosure of Invention
The present invention is directed to a method and system for monitoring leakage of a pipeline, locating leakage, and calculating leakage amount, so as to solve the problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for monitoring pipeline leakage, positioning leakage and calculating leakage amount comprises the following steps:
step 1: acquiring and obtaining the operating parameters of a pipeline to be detected;
step 2: establishing a mathematical model of the pipeline fluid according to the operation parameters collected in the step 1 and based on the pipeline structure and a pipeline fluid conservation equation, and obtaining a pipeline parameter calculation value on the pipeline length;
and step 3: comparing the parameter calculation value with the monitoring value, if the difference value between the parameter calculation value and the monitoring value is greater than a set threshold value, judging that the pipeline to be detected leaks, and giving an alarm; if the difference value between the two values is smaller than the set threshold value, returning to the step 1, continuously acquiring the operation parameters of the pipeline to be tested, simulating the operation of the pipeline, and acquiring a calculated value of the pipeline parameters;
and 4, step 4: after the pipeline is judged to leak, the leaking position is positioned by adopting a negative pressure wave method; calculating the leakage position according to the time difference of transmitting the pressure wave to two ends, which is acquired by a preset monitoring point;
and 5: and calculating the leakage amount according to the leakage amount calculation submodel.
Preferably, step 2 comprises the following substeps:
s21: establishing a mathematical model of the pipeline fluid through a continuous equation and a momentum equation of a conveying medium, and solving the mathematical model by adopting a semi-implicit iterative numerical calculation method;
the expression of the constructed pipeline fluid conservation equation containing the leakage state is as follows:
Figure BDA0002858952020000021
Figure BDA0002858952020000022
in the formula (1) and the formula (2), rho is density, v is speed, t is time, P is pressure, lambda is an on-way resistance coefficient, D is the diameter of the pipeline, alpha is the inclination angle of the pipeline, and g is a gravity constant;
and (3) carrying out spatial and temporal dispersion on the above equations, and sorting to obtain a matrix form of AX ═ B, wherein:
Figure BDA0002858952020000023
Figure BDA0002858952020000031
s22: embedding an elbow calculation sub-model; mainly comprises the following steps:
ζ ═ a × B; wherein,
Figure BDA0002858952020000032
Figure BDA0002858952020000033
ζ＝[0.131+0.159(D/R)3.5](θ/180)； (5)
in the formula (3), the formula (4) and the formula (5), D is the diameter of the pipeline, R is the radius of the bent pipe, theta is the angle of the bent pipe, and zeta is the hydraulic loss of the elbow;
s23: the influence of embedding ambient temperature change to pipeline diameter, and then to the submodel that the fluid velocity influences in the pipeline, the degree of deformation that the pipeline received environment expend with heat and contract with cold can be calculated by following formula:
Figure BDA0002858952020000034
in the formula (6), alphaLThe linear thermal expansion coefficient of an object is shown, T is the temperature, and 1 is the variation;
s24: establishing an embedded pressure wave transmission speed sub-model; the propagation speed of the pressure wave in the medium is the sound speed of the medium, and the calculation formula is as follows:
Figure BDA0002858952020000041
in the formula (7), a is the pressure wave velocity, K is the bulk modulus of the fluid, and ρ is the density of the liquidDegree, E is the modulus of elasticity of the pipe material, D is the pipe diameter, E is the pipe wall thickness, C1Is a correction factor related to the pipe constraint condition;
s25: establishing a resistance calculation sub-model of the embedded gradually-reduced and gradually-expanded pipe, wherein the resistance coefficient of the gradually-expanded pipe can be obtained by the following formula:
Figure BDA0002858952020000042
Figure BDA0002858952020000043
Figure BDA0002858952020000044
wherein K ═ aln (re) + b;
the drag coefficient of the reducer can be obtained by the following formula:
Figure BDA0002858952020000045
Figure BDA0002858952020000046
Figure BDA0002858952020000047
when 0 & lttheta & lt 30 DEG:
A1/A2<4:
Figure BDA0002858952020000048
A1/A2≥4:
Figure BDA0002858952020000051
when theta is more than or equal to 30 degrees:
A1/A2＜4：
Figure BDA0002858952020000052
A1/A2≥4：
Figure BDA0002858952020000053
a1＝-0.001θ+0.0082；
when theta is more than or equal to 30 degrees and less than or equal to 50 degrees:
b1＝0.0076θ+0.1725；
when 50 DEG.ltoreq.theta:
b1＝0.0266θ-0.7743。
setting the threshold value in step 3 as the set threshold pressure difference Δ PthWhen | Pcal-Pmon|＞ΔPthI.e. a leak is judged to have occurred.
Preferably, the specific leak location method in step 4 is as follows: two monitoring points are arranged on the pipeline to be detected, and when leakage occurs, the time when the monitoring point 1 receives a negative pressure wave signal is t1The time when the monitoring point 2 receives the negative pressure wave signal is t2The time difference between the two is delta t ═ t2-t1According to the negative pressure wave method, the calculation formula of the leakage position is as follows:
Figure BDA0002858952020000054
in the formula (8), L is the length of the pipeline, X is the distance from the leakage point to the head end, a is the pressure wave velocity, and V is the flow velocity of the fluid in the pipeline.
Preferably, in the step 5, a submodel is calculated according to the leakage amount, and the principle of a water hammer formula is used as an entry point of leakage calculation; the formula for calculating the leakage amount is as follows:
Figure BDA0002858952020000061
in formula (9), MLFor mass flow, A is the pipeline cross-sectional area, a is the pressure wave velocity, and Δ P is the pressure difference before and after the leak.
The operation parameters in step 1 at least include inlet pressure, inlet flow, inlet medium temperature, inlet ambient temperature, outlet pressure, outlet flow, outlet medium temperature, outlet ambient temperature, pipe node pressure, pipe node medium temperature, and pipe node ambient temperature.
The operation parameters in the step 1 comprise the length L of the pipeline to be measured, the diameter D of the pipeline to be measured, the pipeline composition structure, the pressure wave velocity a, the density rho of the pipeline conveying medium, the inlet pressure, the inlet flow, the outlet pressure and the outlet flow.
A system for monitoring pipeline leakage, positioning leakage and calculating leakage amount comprises a pipeline real-time monitoring device, a programmable logic controller, a terminal server, a central database, a leakage-free simulation workstation, a leakage-free simulation automatic backup server, a leakage simulation workstation, a leakage-free simulation automatic backup server and a display server;
the programmable logic controller collects the measurement parameters of the real-time monitoring device of the pipeline to be measured in a centralized manner;
the front end of the terminal server is connected with the programmable logic controller, and the rear end of the terminal server is connected with the central database and is used for acquiring acquisition parameters and transmitting the acquisition parameters into the central database;
the central database is used as a data storage device and is used for storing all monitoring and calculating data in the whole system;
the leakage-free simulation workstation is used for simulating a leakage-free running state of the pipeline, and the leakage simulation workstation is used for simulating a leakage running state of the pipeline;
the non-leakage simulation automatic backup server and the leakage simulation automatic backup server are used for backing up and storing simulation calculation data of the pipeline to be tested;
the display server is installed in the pipeline control room and is used for displaying monitoring and simulation data, forecasting warnings and leakage information.
Preferably, the pipeline real-time monitoring device comprises an inlet pressure sensor, an inlet flow meter, an inlet medium temperature sensor, an inlet environment temperature sensor, a pipeline node pressure sensor, a pipeline node medium temperature sensor, a pipeline node environment temperature sensor, an outlet pressure sensor, an outlet flow meter, an outlet medium temperature sensor and an outlet environment temperature sensor; the inlet pressure sensor, the inlet flowmeter, the inlet medium temperature sensor and the inlet environment temperature sensor are arranged at the inlet position of the pipeline to be measured and are used for measuring the inlet pressure, the flow, the medium temperature and the environment temperature of the pipeline; the pipeline joint pressure sensor, the medium temperature sensor and the environment temperature sensor are arranged at preset joint positions of the pipeline to be measured and are used for measuring the pressure, the medium temperature and the environment temperature of the middle section of the pipeline to be measured; the installation positions and the installation quantity of the pipeline node pressure sensor, the medium temperature sensor and the environment temperature sensor are determined according to the length and the structural complexity of the pipeline; the outlet pressure sensor, the outlet flowmeter, the outlet medium temperature sensor and the outlet environment temperature sensor are arranged at the outlet position of the pipeline to be measured and are used for measuring the pressure, the flow, the medium temperature and the environment temperature at the outlet of the pipeline to be measured.
Compared with the prior art, the invention provides a method and a system for monitoring pipeline leakage, positioning leakage and calculating leakage amount, which have the following beneficial effects: on the basis of a large number of experiments and CFD verification, the hydraulic loss sub-model of the bent pipe, the temperature-to-pipe diameter influence sub-model, the reducing-gradually-expanding pipe sub-model, the pressure wave velocity sub-model and the like are independently developed, the limitation of the three-dimensional pipeline in one-dimensional calculation is broken, and the calculation precision and the calculation efficiency are good. The leakage quantity calculation model which is independently developed is embedded, and the leakage positioning and leakage quantity early warning functions are provided when the pipeline leakage monitoring is carried out.
Additional features and advantages of the invention will be set forth in the description which follows, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
FIG. 1 is a block diagram of a system configuration according to an embodiment of the present invention;
FIG. 2 is a process flow diagram of the real-time pipeline monitoring system of the present invention;
FIG. 3 is a system flow diagram of a pipeline simulation calculation program;
FIG. 4 is a schematic view of a bend configuration of a transport conduit;
FIG. 5 is a schematic view of a divergent structure of a transport pipe;
FIG. 6 is a schematic view of a pipe reducer structure;
FIG. 7 is a schematic diagram of the leakage location by the negative pressure wave method;
FIG. 8 is a main page of a visualization interface of the present invention;
FIG. 9 is a calculation result display diagram of a visualization interface according to the present invention;
FIG. 10 is a diagram illustrating a calculation result of a visualization interface according to the present invention;
FIG. 11 is a calculation result display diagram of a visualization interface according to the present invention;
FIG. 12 is a calculation result display diagram of a visualization interface according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1-12, the present application mainly includes three parts, wherein, the first part is a real-time pipeline monitoring device;
in this embodiment, the following are mainly arranged: the system comprises an inlet pressure sensor, an inlet flow meter, an inlet medium temperature sensor, an inlet environment temperature sensor, an outlet flow meter, an outlet medium temperature sensor and an outlet environment temperature sensor. In the present embodiment, the pipeline length is 10km, and two monitoring points are arranged at positions of 1km and 9km according to the pipeline length, namely, a pressure sensor, a medium temperature sensor and an ambient temperature sensor are arranged at the monitoring positions. All sensors transmit monitoring data to a terminal server through a PLC (programmable logic controller), and then transmit the monitoring data to a central data memory; the significance of the step is to monitor the operation parameters of the pipeline in real time, provide input parameters for the subsequent analog calculation and leakage monitoring of the pipeline and judge and compare data sources.
The second part is a pipeline simulation calculation system, specifically, for a pipeline to be detected, firstly analyzing a pipeline structure and establishing a pipeline model; describing the motion state of the medium fluid of the pipeline through a continuous equation and a momentum equation of the medium fluid; and carrying out semi-implicit dispersion on the time and space items to obtain a numerical matrix of the pipeline simulation calculation. In this embodiment, all the pipelines are divided into 2000 control bodies, and the calculation interval Δ t of the space is 0.02 s.
The pipeline simulation calculation system reads the real-time monitoring parameters of the pipeline in the central database and uses the parameters as input values and boundary conditions of the pipeline simulation calculation. And (3) solving the pressure and flow of all the control bodies under the current time item through the workstation, further iterating to obtain the pressure value under the next time item, and repeating the steps to calculate the parameters such as the pressure and flow at all the moments and on all the control bodies.
The third part is an interface display part; the invention provides a display server which is arranged in a control room for displaying a webpage interface and a movable APP interface, wherein the display server reads calculation and monitoring parameters from a central database for displaying results; please refer to fig. 8. Fig. 8 is a main interface displayed, the pipeline monitoring system will mainly stay on the interface when in operation, the middle box is a result graph of the pipeline to be detected, the position of the monitoring point and the basic structure parameter of the pipeline are marked in the graph, if leakage occurs, a leakage early warning mark appears at the corresponding leakage position, and information such as the leakage position and the leakage amount is displayed.
Referring to fig. 9-12, fig. 9 shows the calculated pressure and flow rate of the pipeline varying with the distance between the pipelines when the pipeline leaks, and the calculated pressure and flow rate varying with the distance between the pipelines when there is no leakage are two straight lines, and when a leakage occurs, the pressure and flow rate at the leakage point will decrease due to the existence of the negative pressure wave, and the range of the pressure decrease will expand due to the diffusion of the negative pressure wave, and the flow rate after the leakage point will suddenly drop.
Fig. 10 is a calculation result display diagram of a visualization interface according to the present invention, in which the left graph shows the variation of the difference between the calculated pressure in the pipeline leakage state and the calculated pressure in the non-leakage state with the pipeline distance, and the right graph shows the variation of the difference between the calculated flow in the pipeline leakage state and the calculated flow in the non-leakage state with the pipeline distance. The difference between the pressure and the flow rate in the no-leak state is substantially 0, and when a leak occurs, the pressure difference at the leak position increases and spreads to both ends of the pipe, and the same tendency also occurs in the flow rate difference.
The left graph of fig. 11 shows the monitored pressure at two monitoring points as a function of time, and the right graph shows the monitored flow at two monitoring points as a function of time. As can be seen from the figure, the leakage state is judged to occur when the pressure difference between the two monitoring points reaches a certain threshold value.
FIG. 12 is a graphical representation of the results of calculations for a visualization interface of the present invention, wherein the left graph shows the leakage flow rate over time. The leakage flow is 0 in the non-leakage state, and the calculated leakage flow can be displayed in the leakage state.
Specifically, the method comprises the following steps:
a method for monitoring pipeline leakage, positioning leakage and calculating leakage amount comprises the following steps:
step 1: acquiring and obtaining the operating parameters of a pipeline to be detected;
step 2: establishing a mathematical model of the pipeline fluid according to the operation parameters collected in the step 1 and based on the pipeline structure and a pipeline fluid conservation equation, and obtaining a pipeline parameter calculation value on the pipeline length;
and step 3: comparing the parameter calculation value with the monitoring value, if the difference value between the parameter calculation value and the monitoring value is greater than a set threshold value, judging that the pipeline to be detected leaks, and giving an alarm; if the difference value between the two values is smaller than the set threshold value, returning to the step 1, continuously acquiring the operation parameters of the pipeline to be tested, simulating the operation of the pipeline, and acquiring a calculated value of the pipeline parameters;
and 4, step 4: after the pipeline is judged to leak, the leaking position is positioned by adopting a negative pressure wave method; calculating the leakage position according to the time difference of the acquired parameters of the preset monitoring points and the transmission speed of the pressure wave in the pipeline;
and 5: and calculating the leakage amount according to the leakage amount calculation submodel.
Wherein, the step 2 comprises the following substeps:
s21: establishing a mathematical model of the pipeline fluid through a continuous equation and a momentum equation of a conveying medium, and solving the mathematical model by adopting a semi-implicit iterative numerical calculation method;
the expression of the constructed pipeline fluid conservation equation containing the leakage state is as follows:
Figure BDA0002858952020000101
Figure BDA0002858952020000102
in the formula (1) and the formula (2), rho is density, v is speed, t is time, P is pressure, lambda is an on-way resistance coefficient, D is the diameter of the pipeline, alpha is the inclination angle of the pipeline, and g is a gravity constant;
and (3) carrying out spatial and temporal dispersion on the above equations, and sorting to obtain a matrix form of AX ═ B, wherein:
Figure BDA0002858952020000111
Figure BDA0002858952020000112
s22: embedding an elbow calculation sub-model; mainly comprises the following steps:
ζ ═ a × B; wherein,
Figure BDA0002858952020000113
Figure BDA0002858952020000114
ζ＝[0.131+0.159(D/R)3.5](θ/180)； (5)
in the formula (3), the formula (4) and the formula (5), D is the diameter of the pipeline, R is the radius of the bent pipe, theta is the angle of the bent pipe, and zeta is the hydraulic loss of the elbow;
s23: the influence of embedding ambient temperature change to pipeline diameter, and then to the submodel that the fluid velocity influences in the pipeline, the degree of deformation that the pipeline received environment expend with heat and contract with cold can be calculated by following formula:
Figure BDA0002858952020000121
in the formula (6), alphaLThe linear thermal expansion coefficient of an object is shown, T is the temperature, and l is the variation;
s24: establishing an embedded pressure wave transmission speed sub-model; the propagation speed of the pressure wave in the medium is the sound speed of the medium, and the calculation formula is as follows:
Figure BDA0002858952020000122
in the formula (7), a is the pressure wave velocity, K is the bulk modulus of the fluid, ρ is the density of the liquid, E is the elastic modulus of the pipe material, D is the pipe diameter, E is the pipe wall thickness, and C is1Is a correction factor related to the pipe constraint condition;
s25: establishing a resistance calculation sub-model of the embedded gradually-reduced and gradually-expanded pipe, wherein the resistance coefficient of the gradually-expanded pipe can be obtained by the following formula:
Figure BDA0002858952020000123
Figure BDA0002858952020000124
Figure BDA0002858952020000125
wherein K ═ aln (re) + b;
the drag coefficient of the reducer can be obtained by the following formula:
Figure BDA0002858952020000126
Figure BDA0002858952020000131
Figure BDA0002858952020000132
when 0 is more than or equal to theta and less than 30 degrees:
A1/A2＜4：
Figure BDA0002858952020000133
A1/A2≥4：
Figure BDA0002858952020000134
when theta is more than or equal to 30 degrees:
A1/A2＜4：
Figure BDA0002858952020000135
A1/A2≥4：
Figure BDA0002858952020000136
a1＝-0.001θ+0.0082；
when theta is more than or equal to 30 degrees and less than or equal to 50 degrees:
b1＝0.0076θ+0.1725；
when 50 DEG.ltoreq.theta:
b1＝0.0266θ-0.7743。
setting the threshold value in step 3 as the set threshold pressure difference Δ PthWhen | Pcal-Pmon|＞ΔPthI.e. a leak is judged to have occurred.
The specific leakage positioning method in the step 4 comprises the following steps: two monitoring points are arranged on the pipeline to be detected, and when leakage occurs, the time when the monitoring point 1 receives a negative pressure wave signal is t1The time when the monitoring point 2 receives the negative pressure wave signal is t2The time difference between the two is delta t ═ t2-t1According to the negative pressure wave method, the calculation formula of the leakage position is as follows:
Figure BDA0002858952020000141
in the formula (8), L is the length of the pipeline, X is the distance from the leakage point to the head end, a is the pressure wave velocity, and V is the flow velocity of the fluid in the pipeline.
In step 5, calculating a sub-model according to the leakage amount, and taking the principle of a water hammer formula as an entry point of leakage calculation; the formula for calculating the leakage amount is as follows:
Figure BDA0002858952020000142
in formula (9), MLFor mass flow, A is the cross-sectional area of the pipeline,a is the pressure wave velocity and Δ P is the differential pressure before and after the leak point.
The operation parameters in step 1 at least include inlet pressure, inlet flow, inlet medium temperature, inlet ambient temperature, outlet pressure, outlet flow, outlet medium temperature, outlet ambient temperature, pipe node pressure, pipe node medium temperature, and pipe node ambient temperature.
The operation parameters in the step 1 comprise the length L of the pipeline to be measured, the diameter D of the pipeline to be measured, the pipeline composition structure, the pressure wave velocity a, the density rho of the pipeline conveying medium, the inlet pressure, the inlet flow, the outlet pressure and the outlet flow.
A system for monitoring pipeline leakage, positioning leakage and calculating leakage amount,
the system comprises a pipeline real-time monitoring device, a programmable logic controller, a terminal server, a central database, a non-leakage simulation workstation, a non-leakage simulation automatic backup server, a leakage simulation workstation, a non-leakage simulation automatic backup server and a display server;
the programmable logic controller collects the measurement parameters of the real-time monitoring device of the pipeline to be measured in a centralized manner;
the front end of the terminal server is connected with the programmable logic controller, and the rear end of the terminal server is connected with the central database and is used for acquiring acquisition parameters and transmitting the acquisition parameters into the central database;
the central database is used as a data storage device and is used for storing all monitoring and calculating data in the whole system;
the leakage-free simulation workstation is used for simulating a leakage-free running state of the pipeline, and the leakage simulation workstation is used for simulating a leakage running state of the pipeline;
the non-leakage simulation automatic backup server and the leakage simulation automatic backup server are used for backing up and storing simulation calculation data of the pipeline to be tested;
the display server is installed in the pipeline control room and is used for displaying monitoring and simulation data, forecasting warnings and leakage information.
The pipeline real-time monitoring device comprises an inlet pressure sensor, an inlet flowmeter, an inlet medium temperature sensor, an inlet environment temperature sensor, a pipeline node pressure sensor, a pipeline node medium temperature sensor, a pipeline node environment temperature sensor, an outlet pressure sensor, an outlet flowmeter, an outlet medium temperature sensor and an outlet environment temperature sensor; the inlet pressure sensor, the inlet flowmeter, the inlet medium temperature sensor and the inlet environment temperature sensor are arranged at the inlet position of the pipeline to be measured and are used for measuring the inlet pressure, the flow, the medium temperature and the environment temperature of the pipeline; the pipeline joint pressure sensor, the medium temperature sensor and the environment temperature sensor are arranged at preset joint positions of the pipeline to be measured and are used for measuring the pressure, the medium temperature and the environment temperature of the middle section of the pipeline to be measured; the installation positions and the installation quantity of the pipeline node pressure sensor, the medium temperature sensor and the environment temperature sensor are determined according to the length and the structural complexity of the pipeline; the outlet pressure sensor, the outlet flowmeter, the outlet medium temperature sensor and the outlet environment temperature sensor are arranged at the outlet position of the pipeline to be measured and are used for measuring the pressure, the flow, the medium temperature and the environment temperature at the outlet of the pipeline to be measured.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (9)

1. A method for monitoring pipeline leakage, positioning leakage and calculating leakage amount is characterized in that: the method comprises the following steps:
step 1: acquiring and obtaining the operating parameters of a pipeline to be detected;
step 2: establishing a mathematical model of the pipeline fluid according to the operation parameters collected in the step 1 and based on the pipeline structure and a pipeline fluid conservation equation, and obtaining a pipeline parameter calculation value on the pipeline length;
and step 3: comparing the parameter calculation value with the monitoring value, if the difference value between the parameter calculation value and the monitoring value is greater than a set threshold value, judging that the pipeline to be detected leaks, and giving an alarm; if the difference value between the two values is smaller than the set threshold value, returning to the step 1, continuously acquiring the operation parameters of the pipeline to be tested, simulating the operation of the pipeline, and acquiring a calculated value of the pipeline parameters;
and 4, step 4: after the pipeline is judged to leak, the leaking position is positioned by adopting a negative pressure wave method; calculating the leakage position according to the time difference of transmitting the pressure wave to two ends, which is acquired by a preset monitoring point;
and 5: and calculating the leakage amount according to the leakage amount calculation submodel.
2. The method of claim 1, wherein the method comprises the steps of: the step 2 comprises the following substeps:
s21: establishing a mathematical model of the pipeline fluid through a continuous equation and a momentum equation of a conveying medium, and solving the mathematical model by adopting a semi-implicit iterative numerical calculation method;
the expression of the constructed pipeline fluid conservation equation containing the leakage state is as follows:
Figure FDA0002858952010000011
Figure FDA0002858952010000012
in the formula (1) and the formula (2), rho is density, v is speed, t is time, P is pressure, lambda is an on-way resistance coefficient, D is the diameter of the pipeline, alpha is the inclination angle of the pipeline, and g is a gravity constant;
and (3) carrying out spatial and temporal dispersion on the above equations, and sorting to obtain a matrix form of AX ═ B, wherein:
Figure FDA0002858952010000021
Figure FDA0002858952010000022
s22: embedding an elbow calculation sub-model; mainly comprises the following steps:
ζ ═ a × B; wherein,
Figure FDA0002858952010000023
Figure FDA0002858952010000024
ζ＝[0.131+0.159(D/R)3.5](θ/180)； (5)
in the formula (3), the formula (4) and the formula (5), D is the diameter of the pipeline, R is the radius of the bent pipe, theta is the angle of the bent pipe, and zeta is the hydraulic loss of the elbow;
s23: the influence of embedding ambient temperature change to pipeline diameter, and then to the submodel that the fluid velocity influences in the pipeline, the degree of deformation that the pipeline received environment expend with heat and contract with cold can be calculated by following formula:
Figure FDA0002858952010000031
in the formula (6), alphaLThe linear thermal expansion coefficient of an object is shown, T is the temperature, and l is the variation;
s24: establishing an embedded pressure wave transmission speed sub-model; the propagation speed of the pressure wave in the medium is the sound speed of the medium, and the calculation formula is as follows:
Figure FDA0002858952010000032
in the formula (7), a is the pressure wave velocity, K is the bulk modulus of the fluid, ρ is the density of the liquid, E is the elastic modulus of the pipe material, D is the pipe diameter, E is the pipe wall thickness, and C is1For correction factors related to pipe constraints；
S25: establishing a resistance calculation sub-model of the embedded gradually-reduced and gradually-expanded pipe, wherein the resistance coefficient of the gradually-expanded pipe can be obtained by the following formula:
Figure FDA0002858952010000033
Figure FDA0002858952010000034
Figure FDA0002858952010000035
wherein K ═ aln (re) + b;
the drag coefficient of the reducer can be obtained by the following formula:
Figure FDA0002858952010000036
Figure FDA0002858952010000037
Figure FDA0002858952010000038
when 0 & lttheta & lt 30 DEG:
A1/A2<4:
Figure FDA0002858952010000041
A1/A2≥4:
Figure FDA0002858952010000042
when theta is more than or equal to 30 degrees:
A1/A2<4:
Figure FDA0002858952010000043
A1/A2≥4:
Figure FDA0002858952010000044
a1＝-0.001θ+0.0082；
when theta is more than or equal to 30 degrees and less than or equal to 50 degrees:
b1＝0.0076θ+0.1725；
when 50 DEG.ltoreq.theta:
b1＝0.0266θ-0.7743。
3. the method of claim 1, wherein the method comprises the steps of: setting the threshold value in step 3 as the set threshold pressure difference Δ PthWhen | Pcal-Pmon|>ΔPthI.e. a leak is judged to have occurred.
4. The method of claim 1, wherein the method comprises the steps of: the specific leakage positioning method in the step 4 comprises the following steps: two monitoring points are arranged on the pipeline to be detected, and when leakage occurs, the time when the monitoring point 1 receives a negative pressure wave signal is t1The time when the monitoring point 2 receives the negative pressure wave signal is t2The time difference between the two is delta t ═ t2-t1According to the negative pressure wave method, the calculation formula of the leakage position is as follows:
Figure FDA0002858952010000051
in the formula (8), L is the length of the pipeline, X is the distance from the leakage point to the head end, a is the pressure wave velocity, and V is the flow velocity of the fluid in the pipeline.
5. The method of claim 1, wherein the method comprises the steps of: in step 5, calculating a sub-model according to the leakage amount, and taking the principle of a water hammer formula as an entry point of leakage calculation; the formula for calculating the leakage amount is as follows:
Figure FDA0002858952010000052
in formula (9), MLFor mass flow, A is the pipeline cross-sectional area, a is the pressure wave velocity, and Δ P is the pressure difference before and after the leak.
6. The method of claim 1, wherein the method comprises the steps of: the operation parameters in step 1 at least include inlet pressure, inlet flow, inlet medium temperature, inlet ambient temperature, outlet pressure, outlet flow, outlet medium temperature, outlet ambient temperature, pipe node pressure, pipe node medium temperature, and pipe node ambient temperature.
7. The method of claim 6, wherein the method comprises the steps of: the operation parameters in the step 1 comprise the length L of the pipeline to be measured, the diameter D of the pipeline to be measured, the pipeline composition structure, the pressure wave velocity a, the density rho of the pipeline conveying medium, the inlet pressure, the inlet flow, the outlet pressure and the outlet flow.
8. The utility model provides a system for pipeline leakage monitoring, leak location and leakage volume calculation which characterized in that: the system comprises a pipeline real-time monitoring device, a programmable logic controller, a terminal server, a central database, a non-leakage simulation workstation, a non-leakage simulation automatic backup server, a leakage simulation workstation, a non-leakage simulation automatic backup server and a display server;
the programmable logic controller collects the measurement parameters of the real-time monitoring device of the pipeline to be measured in a centralized manner;
the front end of the terminal server is connected with the programmable logic controller, and the rear end of the terminal server is connected with the central database and is used for acquiring acquisition parameters and transmitting the acquisition parameters into the central database;
the central database is used as a data storage device and is used for storing all monitoring and calculating data in the whole system;
the leakage-free simulation workstation is used for simulating a leakage-free running state of the pipeline, and the leakage simulation workstation is used for simulating a leakage running state of the pipeline;
the non-leakage simulation automatic backup server and the leakage simulation automatic backup server are used for backing up and storing simulation calculation data of the pipeline to be tested;
the display server is installed in the pipeline control room and is used for displaying monitoring and simulation data, forecasting warnings and leakage information.
9. The system of claim 8, wherein the system comprises: the pipeline real-time monitoring device comprises an inlet pressure sensor, an inlet flowmeter, an inlet medium temperature sensor, an inlet environment temperature sensor, a pipeline node pressure sensor, a pipeline node medium temperature sensor, a pipeline node environment temperature sensor, an outlet pressure sensor, an outlet flowmeter, an outlet medium temperature sensor and an outlet environment temperature sensor; the inlet pressure sensor, the inlet flowmeter, the inlet medium temperature sensor and the inlet environment temperature sensor are arranged at the inlet position of the pipeline to be measured and are used for measuring the inlet pressure, the flow, the medium temperature and the environment temperature of the pipeline; the pipeline joint pressure sensor, the medium temperature sensor and the environment temperature sensor are arranged at preset joint positions of the pipeline to be measured and are used for measuring the pressure, the medium temperature and the environment temperature of the middle section of the pipeline to be measured; the installation positions and the installation quantity of the pipeline node pressure sensor, the medium temperature sensor and the environment temperature sensor are determined according to the length and the structural complexity of the pipeline; the outlet pressure sensor, the outlet flowmeter, the outlet medium temperature sensor and the outlet environment temperature sensor are arranged at the outlet position of the pipeline to be measured and are used for measuring the pressure, the flow, the medium temperature and the environment temperature at the outlet of the pipeline to be measured.
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