Positioning method for leakage of conveying pipeline

Abstract

The invention relates to the technical field of pipeline medium leakage determination, and discloses a method for positioning leakage of a conveying pipeline, which comprises the following steps of: calculating a hydraulic slope i < 1 > of an upstream pump station and a hydraulic slope i < 2 > of a downstream pump station through flow data acquired from the pump stations; according to the outbound pressure data of the upstream pump station, the outbound pressure head h1 of the upstream pump station is calculated, and according to the inbound pressure data of the downstream pump station, the inbound pressure head h2 of the downstream pump station is calculated; respectively determining a leakage point upstream pressure head line equation and a leakage point downstream pressure head line equation by taking the along-line distance length S as an abscissa in a coordinate system and taking the along-line pressure head H as an ordinate in the coordinate system, and solving an intersection point coordinate by combining the leakage point upstream pressure head line equation and the leakage point downstream pressure head line equation; the distance between a leakage point and an upstream pump station is obtained, so that the position of the leakage point and a pressure head are determined, corresponding measures are taken for controlling leakage in time, and loss and waste caused by leakage of a large amount of fluid are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of determining pipeline medium leakage, and in particular to a method for locating pipeline leakage. Background Art

[0002] Pipeline transportation is a mode of transportation that uses pipelines as a means of transportation to transport liquid or gas materials over long distances. It is widely used in the transportation of oil, natural gas and some chemicals. Pipeline transportation systems are usually composed of pipelines, pumping stations, valves, control equipment and monitoring equipment. Pipelines are the main part of the transportation system and are usually made of metal (such as steel, stainless steel, etc.), plastic or other materials. Pumping stations are used to provide the power required for transporting materials. Since the flow of fluids in pipelines needs to overcome resistance, the flow rate of the fluid will gradually decrease. In order to ensure that the fluid can continue to flow in the pipeline, especially in long-distance pipelines, it is necessary to set up multiple pumping stations along the transportation pipeline to provide power for the fluid. Valves and control equipment are mainly used to adjust the flow, pressure and direction of materials, as well as shutdown operations in emergency situations. Monitoring equipment is mainly used to monitor the operating status of pipelines and the flow of materials.

[0003] During pipeline transportation, the pipeline may leak due to material aging, corrosion or mechanical damage. After the leak occurs, quickly locating the pipeline leak point is crucial to timely control and repair the leak.

[0004] In the prior art, the location of pipeline leakage points is usually determined by manual inspection, which is slow, has high labor costs, and cannot control and repair leakage in a timely manner, resulting in a large amount of fluid loss and waste due to leakage. Summary of the invention

[0005] The purpose of the present invention is to provide a method for locating leakage in a conveying pipeline, so as to solve the problem in the prior art that the leakage point is slowly located and the leakage cannot be controlled and repaired in time, resulting in loss and waste of conveying fluid.

[0006] In order to achieve the above object, the present invention provides a method for locating a leakage in a conveying pipeline, which comprises the following steps:

[0007] Step S1: synchronously and regularly collect flow data, inlet pressure data and outlet pressure data from each pump station along the pipeline;

[0008] Step S2: define two pumping stations adjacent to the leakage point as an upstream pumping station and a downstream pumping station along the pipeline transportation direction; read the flow data of the upstream pumping station and calculate the hydraulic gradient i1 of the upstream pumping station; read the flow data of the downstream pumping station and calculate the hydraulic gradient i2 of the downstream pumping station;

[0009] Step S3: reading the outgoing pressure data of the upstream pump station, and calculating the outgoing pressure head h1 of the upstream pump station; reading the incoming pressure data of the downstream pump station, and calculating the incoming pressure head h2 of the downstream pump station;

[0010] Step S4: define the distance length S along the line as the horizontal coordinate in the coordinate system, define the pressure head H along the line as the vertical coordinate in the coordinate system, take the hydraulic gradient i1 of the upstream pumping station as the slope, take the outlet pressure head h1 of the upstream pumping station as the intercept, and establish the pressure head line equation upstream of the leakage point in the above coordinate system;

[0011] In the coordinate system, a fixed point A is drawn with the distance between the downstream pump station and the upstream pump station as the horizontal coordinate value, the inlet pressure head h2 of the downstream pump station as the vertical coordinate value, and the hydraulic gradient i2 of the downstream pump station is used as the slope, and the pressure head line equation downstream of the leakage point is established through the fixed point A;

[0012] Step S5: Combine the pressure head line equation upstream of the leakage point and the pressure head line equation downstream of the leakage point to calculate the horizontal coordinate value of the intersection point. The horizontal coordinate value is the distance between the leakage point and the upstream pump station, and the position of the leakage point is determined.

[0013] Further, step S2 includes step S2-1 and step S2-2;

[0014] Step S2-1: Calculate the hydraulic gradient i1 of the upstream pump station by the following formula:

[0015]

[0016] Where λ1 is the resistance coefficient along the upstream pump station;

[0017] V1 is the flow rate of the fluid in the upstream pump station, in m / s;

[0018] d is the pipe diameter, in meters;

[0019] g is the acceleration due to gravity, which is 9.8 m / s 2 ;

[0020] Step S2-2: Calculate the hydraulic gradient i2 of the downstream pump station by the following formula:

[0021]

[0022] Where λ2 is the resistance coefficient along the downstream pump station;

[0023] V2 is the flow rate of the fluid in the downstream pump station, in m / s;

[0024] d is the pipe diameter, in meters;

[0025] g is the acceleration due to gravity, which is 9.8 m / s 2 .

[0026] Furthermore, step S2-1 also includes step S2-1-1;

[0027] Step S2-1-1: The flow rate V1 of the fluid in the upstream pump station is calculated by the following formula:

[0028]

[0029] Where q1 is the flow rate of the upstream pump station, in m 3 / h;

[0030] π is the ratio of the circumference of a circle, which is 3.14;

[0031] d is the pipe diameter, in meters;

[0032] The flow rate q1 of the upstream pump station is obtained by setting a flow meter in the upstream pump station to measure the flow rate data of the upstream pump station;

[0033] Step S2-2 also includes step S2-2-1;

[0034] Step S2-2-1: The flow rate V2 of the fluid in the downstream pump station is calculated by the following formula:

[0035]

[0036] Where q2 is the flow rate of the downstream pump station, in m 3 / h;

[0037] π is the ratio of the circumference of a circle, which is 3.14;

[0038] d is the pipe diameter, in meters;

[0039] The flow rate q2 of the downstream pumping station is obtained by setting a flow meter in the downstream pumping station to measure the flow data of the downstream pumping station.

[0040] Furthermore, the step S2-1 further includes step S2-1-2,

[0041] Step S2-1-2: Calculate the Reynolds number Re of the fluid in the upstream pump station by the following formula: 上 :

[0042]

[0043] Where V1 is the flow rate of the fluid in the upstream pump station, in m / s;

[0044] d is the pipe diameter, in meters;

[0045] ν is the kinematic viscosity of the fluid, in m 2 / s;

[0046] The lower critical Reynolds number Re1 is calculated by the following formula:

[0047]

[0048] Where d is the pipe diameter, in meters;

[0049] e is the absolute roughness of the pipe, in mm;

[0050] The upper critical Reynolds number Re2 is calculated by the following formula:

[0051]

[0052] Where d is the pipe diameter, in meters;

[0053] e is the absolute roughness of the pipe, in mm;

[0054] The Reynolds number Re of the fluid in the upstream pump station 上 Compare with the lower critical Reynolds number Re1 and the upper critical Reynolds number Re2;

[0055] If 上 <2000, it is judged that the fluid in the upstream pump station is in a laminar flow state, and the corresponding flow resistance coefficient λ1 of the upstream pump station is calculated by the following formula:

[0056]

[0057] If 2000≤Re 上 <Re1, it is judged that the fluid in the upstream pump station is in the turbulent hydraulic smooth area, and when 2000≤Re 上 <10 5 When , the corresponding upstream pump station along the resistance coefficient λ1 is calculated by the following formula:

[0058]

[0059] When 10 5 <Re 上 When <Re1, the corresponding resistance coefficient λ1 of the upstream pump station is calculated by the following formula:

[0060]

[0061] If Re1≤Re 上 <Re2, it is judged that the fluid in the upstream pump station is in the turbulent mixed friction zone, and the corresponding resistance coefficient λ1 of the upstream pump station is calculated by the following formula:

[0062]

[0063] Where d is the pipe diameter, in meters;

[0064] e is the absolute roughness of the pipe, in mm.

[0065] If 上 ≥Re2, it is judged that the fluid in the upstream pump station is in the turbulent complete roughness area, and the corresponding longitudinal resistance coefficient λ1 of the upstream pump station is calculated by the following formula:

[0066]

[0067] Where d is the pipe diameter, in meters;

[0068] e is the absolute roughness of the pipe, in mm.

[0069] Furthermore, the step S2-2 also includes step S2-2-2;

[0070] Step S2-2-2: Calculate the Reynolds number Re of the fluid in the downstream pump station by the following formula: 下 :

[0071]

[0072] Where V2 is the flow rate of the fluid in the downstream pump station, in m / s;

[0073] d is the pipe diameter, in meters;

[0074] ν is the kinematic viscosity of the fluid, in m 2 / s;

[0075] The lower critical Reynolds number Re1 is calculated by the following formula:

[0076]

[0077] Where d is the pipe diameter, in meters;

[0078] e is the absolute roughness of the pipe, in mm;

[0079] The upper critical Reynolds number Re2 is calculated by the following formula:

[0080]

[0081] Where d is the pipe diameter, in meters;

[0082] e is the absolute roughness of the pipe, in mm;

[0083] The Reynolds number Re of the fluid in the downstream pump station 下 Compare with the lower critical Reynolds number Re1 and the upper critical Reynolds number Re2;

[0084] If 下<2000, it is judged that the fluid in the downstream pump station is in a laminar flow state, and the corresponding flow resistance coefficient λ2 of the downstream pump station is calculated by the following formula:

[0085]

[0086] If 2000≤Re 下 <Re1, it is judged that the fluid in the downstream pump station is in the turbulent hydraulic smooth area;

[0087] And when 2000≤Re 下 <10 5 When the downstream pump station has a resistance coefficient λ1, the following formula is used to calculate the resistance coefficient λ1 along the downstream pump station:

[0088]

[0089] When 10 5 <Re 下 When <Re1, the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula:

[0090]

[0091] If Re1≤Re 下 <Re2, it is judged that the fluid in the downstream pump station is in the turbulent mixed friction zone, and the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula:

[0092]

[0093] Where d is the pipe diameter, in meters;

[0094] e is the absolute roughness of the pipe, in mm.

[0095] If 下 ≥Re2, it is judged that the fluid in the downstream pump station is in the turbulent complete roughness area, and the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula:

[0096]

[0097] Where d is the pipe diameter, in meters;

[0098] e is the absolute roughness of the pipe, in mm.

[0099] Further, the step S3 includes step S3-1 and step S3-2;

[0100] Step S3-1: Calculate the outlet pressure h1 of the upstream pump station by the following formula:

[0101]

[0102] In the formula, p 上 It is the outlet pressure data of the upstream pump station, in MPa; it is read by setting a pressure sensor at the outlet of the upstream pump station;

[0103] ρ is the density of the fluid transported in the pipeline, in kg / m 3 ;

[0104] h 上 is the elevation of the upstream pumping station, in m;

[0105] Step S3-2: Calculate the inlet pressure h2 of the downstream pump station by the following formula:

[0106]

[0107] In the formula, p 下 It is the inlet pressure data of the downstream pump station, in MPa; it is read by setting a pressure sensor at the inlet of the downstream pump station;

[0108] ρ is the density of the fluid transported in the pipeline, in kg / m 3 ;

[0109] h 下 is the elevation of the downstream pumping station, in meters.

[0110] Furthermore, step S1-1 is included between step S1 and step S2;

[0111] Step S1-1: In two pumping stations adjacent to the leakage point, if at the same time, the flow rate of the upstream pumping station increases and the flow rate of the downstream pumping station decreases, it is determined that a leakage occurs between the upstream pumping station and the downstream pumping station, and step S2 is continued; otherwise, it is considered that no leakage occurs between the upstream pumping station and the downstream pumping station, and step S2 is not performed.

[0112] Furthermore, it also includes:

[0113] Step S6: Combine the pressure head line equation upstream of the leak point and the pressure head line equation downstream of the leak point to find the ordinate value of the intersection point. The ordinate value is the pressure head h of the leak point. 泄 .

[0114] Compared with the prior art, the method for locating a pipeline leakage provided by the present invention has the following beneficial effects:

[0115] The present invention provides a method for locating pipeline leakage. The method calculates the hydraulic gradient i1 of the upstream pump station through the flow data of the upstream pump station of the leakage point; and calculates the outlet pressure head h1 of the upstream pump station according to the outlet pressure data of the upstream pump station; the hydraulic gradient i1 of the upstream pump station represents the ratio between the pressure head size of the fluid in the upstream pump station after the upstream pump station and the distance length between the location and the upstream pump station; the hydraulic gradient i2 of the downstream pump station is calculated through the flow data of the downstream pump station of the leakage point. ; and according to the outlet pressure data of the downstream pump station, calculate the inlet pressure head h2 of the downstream pump station; the hydraulic gradient i2 of the downstream pump station represents the ratio between the pressure head size of the fluid in the downstream pump station before the downstream pump station and the distance length between the point and the downstream pump station; if there is no leakage between the upstream pump station and the downstream pump station, the hydraulic gradient i1 of the upstream pump station should be consistent with the hydraulic gradient i2 of the downstream pump station, but after the leakage occurs, the pressure head changes due to the pipeline leakage, and the hydraulic gradient changes from the leakage point. will change; a coordinate system is established by taking the length of the distance S along the line as the horizontal coordinate in the coordinate system, defining the pressure head H along the line as the vertical coordinate in the coordinate system, and then taking the hydraulic gradient i1 of the upstream pumping station as the slope, and taking the outlet pressure head h1 of the upstream pumping station as the intercept, an equation of the upstream pressure head line of the leakage point is established in the coordinate system; the content represented by the equation of the upstream pressure head line of the leakage point is the pressure head size corresponding to each point along the line with the upstream pumping station as the starting point; in the same coordinate system, the distance length between the downstream pumping station and the upstream pumping station is taken as the horizontal coordinate The fixed point A is plotted with the inlet pressure head h2 of the downstream pump station as the ordinate value, and the hydraulic gradient i2 of the downstream pump station is used as the slope. The pressure head line equation downstream of the leakage point is established through the fixed point A; the horizontal coordinate value of the intersection point is calculated by the pressure head line equation upstream of the leakage point and the pressure head line equation downstream of the leakage point, so as to obtain the distance between the leakage point and the upstream pump station, and realize the positioning of the leakage point, so as to facilitate timely control and subsequent recovery of the leakage, thereby avoiding the loss and waste of a large amount of fluid due to leakage due to failure to timely control and repair the leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0116] Figure 1 is a flow chart of the steps of a positioning method according to an embodiment of the present invention;

[0117] Figure 2 It is a function graph corresponding to the pressure head line equation upstream of the leakage point and the pressure head line equation downstream of the leakage point in the embodiment of the present invention.

[0118] In the figure, 1, upstream pumping station; 2, downstream pumping station; 3, leakage point; 100, pressure head line equation upstream of the leakage point; 200, pressure head line equation downstream of the leakage point. DETAILED DESCRIPTION

[0119] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0120] like Figure 1-2 As shown, a method for locating a pipeline leakage according to an embodiment of the present invention comprises the following steps:

[0121] Step S1: synchronously and regularly collect flow data, inlet pressure data and outlet pressure data from each pump station along the pipeline;

[0122] Step S2: define two pumping stations adjacent to the leakage point as upstream pumping station 1 and downstream pumping station 2 along the pipeline transportation direction; read the flow data of upstream pumping station 1, and calculate the hydraulic gradient i1 of upstream pumping station 1; read the flow data of downstream pumping station 2, and calculate the hydraulic gradient i2 of downstream pumping station 2;

[0123] Step S3: reading the outgoing pressure data of the upstream pump station 1, and calculating the outgoing pressure head h1 of the upstream pump station 1; reading the incoming pressure data of the downstream pump station 2, and calculating the incoming pressure head h2 of the downstream pump station 2;

[0124] Step S4: define the distance length S along the line as the horizontal coordinate in the coordinate system, define the pressure head H along the line as the vertical coordinate in the coordinate system, take the hydraulic gradient i1 of the upstream pumping station 1 as the slope, take the outlet pressure head h1 of the upstream pumping station 1 as the intercept, and establish the pressure head line equation upstream of the leakage point in the above coordinate system;

[0125] In the coordinate system, a fixed point A is drawn with the distance between the downstream pump station 2 and the upstream pump station 1 as the horizontal coordinate value, the inlet pressure head h2 of the downstream pump station 2 as the vertical coordinate value, and the hydraulic gradient i2 of the downstream pump station 2 is used as the slope, and the pressure head line equation downstream of the leakage point is established through the fixed point A;

[0126] Step S5: Combine the pressure head line equation upstream of the leakage point and the pressure head line equation downstream of the leakage point to calculate the horizontal coordinate value of the intersection point. The horizontal coordinate value is the distance between the leakage point 3 and the upstream pump station 1, and the position of the leakage point is determined.

[0127] Based on the above technical solution, the hydraulic gradient i1 of the upstream pumping station 1 is calculated through the flow data of the upstream pumping station 1 of the leakage point 3; and the outlet pressure head h1 of the upstream pumping station 1 is calculated according to the outlet pressure data of the upstream pumping station 1; the hydraulic gradient i1 of the upstream pumping station 1 represents the ratio between the pressure head size of the fluid in the upstream pumping station 1 at various points along the line after the upstream pumping station 1 and the distance length between the point and the upstream pumping station 1; the hydraulic gradient i2 of the downstream pumping station 2 is calculated through the flow data of the downstream pumping station 2 of the leakage point 3; and according to the outlet pressure data of the downstream pumping station 2 The inlet pressure data of the downstream pump station 2 is used to calculate the inlet pressure head h2 of the downstream pump station 2; the hydraulic gradient i2 of the downstream pump station 2 represents the ratio between the pressure head size of the fluid in the downstream pump station 2 before the downstream pump station 2 and the distance between the point and the downstream pump station 2; if there is no leakage between the upstream pump station 1 and the downstream pump station 2, the hydraulic gradient i1 of the upstream pump station 1 should be consistent with the hydraulic gradient i2 of the downstream pump station 2, but after the leakage occurs, the pressure head changes due to the pipeline leakage, and the hydraulic gradient will change from the leakage point 3; A coordinate system is established by taking the length of the distance S along the line as the horizontal coordinate in the coordinate system, defining the pressure head H along the line as the vertical coordinate in the coordinate system, and then taking the hydraulic gradient i1 of the upstream pumping station 1 as the slope and the outlet pressure head h1 of the upstream pumping station 1 as the intercept, to establish the upstream pressure head line equation 100 of the leakage point in the coordinate system; the content represented by the upstream pressure head line equation 100 is the pressure head size corresponding to each point along the line starting from the upstream pumping station 1; in the same coordinate system, the distance length between the downstream pumping station 2 and the upstream pumping station 1 is the horizontal coordinate value and the downstream pumping station 1 is the vertical coordinate value. 2 is used as the ordinate value to draw the fixed point A, and the hydraulic gradient i2 of the downstream pump station is used as the slope, and the downstream pressure head line equation 200 of the leakage point is established through the fixed point A; by jointly calculating the horizontal coordinate value of the intersection point of the upstream pressure head line equation 100 of the leakage point and the downstream pressure head line equation 200 of the leakage point, the distance between the leakage point 3 and the upstream pump station 1 can be obtained, and the leakage point 3 can be located, which is convenient for timely control and subsequent recovery of the leakage, thereby avoiding the loss and waste of a large amount of fluid due to leakage due to failure to timely control and repair the leakage.

[0128] Further, in order to standardize the calculation and acquisition method of the hydraulic gradient i1 of the upstream pump station 1 and the hydraulic gradient i2 of the downstream pump station 2, so as to ensure the establishment of the correct pressure head line equation upstream of the leakage point and the pressure head line equation downstream of the leakage point, step S2 includes step S2-1 and step S2-2;

[0129] Step S2-1: Calculate the hydraulic gradient i1 of the upstream pump station 1 by the following formula:

[0130]

[0131] Where λ1 is the resistance coefficient along the upstream pump station 1;

[0132] V1 is the flow rate of the fluid in the upstream pump station 1, in m / s;

[0133] d is the pipe diameter, in meters;

[0134] g is the acceleration due to gravity, which is 9.8 m / s 2 ;

[0135] Step S2-2: Calculate the hydraulic gradient i2 of the downstream pump station 2 by the following formula:

[0136]

[0137] In the formula, λ2 is the resistance coefficient along the way corresponding to the downstream pump station 2;

[0138] V2 is the flow rate of the fluid in the downstream pump station 2, in m / s;

[0139] d is the pipe diameter, in meters;

[0140] g is the acceleration due to gravity, which is 9.8 m / s 2 .

[0141] Further, in order to obtain the flow rate V1 of the fluid in the upstream pumping station 1 and the flow rate V2 of the fluid in the downstream pumping station 2 by timing and synchronizing the flow data collected from each pumping station along the pipeline; step S2-1 also includes step S2-1-1;

[0142] Step S2-1-1: The flow rate V1 of the fluid in the upstream pump station 1 is calculated by the following formula:

[0143]

[0144] Where q1 is the flow rate of upstream pump station 1, in m 3 / h;

[0145] π is the ratio of the circumference of a circle, which is 3.14;

[0146] d is the pipe diameter, in meters;

[0147] The flow rate q1 of the upstream pump station 1 is obtained by setting a flow meter in the upstream pump station 1 to measure the flow rate data of the upstream pump station 1;

[0148] Step S2-2 also includes step S2-2-1;

[0149] Step S2-2-1: The flow rate V2 of the fluid in the downstream pump station 2 is calculated by the following formula:

[0150]

[0151] Where q2 is the flow rate of downstream pump station 2, in m3 / h;

[0152] π is the ratio of the circumference of a circle, which is 3.14;

[0153] d is the pipe diameter, in meters;

[0154] The flow rate q2 of the downstream pumping station 2 is obtained by setting a flow meter in the downstream pumping station 2 to measure the flow rate data of the downstream pumping station 2 .

[0155] Furthermore, since the resistance coefficient λ1 corresponding to the upstream pump station 1 is related to the corresponding flow state, different flow states correspond to different calculation methods; the step S2-1 also includes step S2-1-2,

[0156] Step S2-1-2: Calculate the Reynolds number Re of the fluid in the upstream pump station 1 by the following formula: 上 :

[0157]

[0158] Where V1 is the flow rate of the fluid in the upstream pump station 1, in m / s;

[0159] d is the pipe diameter, in meters;

[0160] ν is the kinematic viscosity of the fluid, in m 2 / s;

[0161] The lower critical Reynolds number Re1 is calculated by the following formula:

[0162]

[0163] Where d is the pipe diameter, in meters;

[0164] e is the absolute roughness of the pipe, in mm;

[0165] And the upper critical Reynolds number Re2 is calculated by the following formula:

[0166]

[0167] Where d is the pipe diameter, in meters;

[0168] e is the absolute roughness of the pipe, in mm;

[0169] The Reynolds number Re of the fluid in the upstream pump station 1 上 Compare with the lower critical Reynolds number Re1 and the upper critical Reynolds number Re2;

[0170] If 上<2000, it is judged that the fluid in the upstream pump station is in a laminar flow state, and the corresponding flow resistance coefficient λ1 of the upstream pump station is calculated by the following formula:

[0171]

[0172] If 2000≤Re 上 <Re1, it is judged that the fluid in the upstream pump station is in the turbulent hydraulic smooth area, and when 2000≤Re 上 <10 5 When , the corresponding upstream pump station along the line resistance coefficient λ1 is calculated by the following formula:

[0173]

[0174] When 10 5 <Re 上 When <Re1, the corresponding resistance coefficient λ1 of the upstream pump station is calculated by the following formula:

[0175]

[0176] If Re1≤Re 上 <Re2, it is judged that the fluid in the upstream pump station is in the turbulent mixed friction zone, and the corresponding upstream pump station along the resistance coefficient λ1 is calculated by the following formula:

[0177]

[0178] Where d is the pipe diameter, in meters;

[0179] e is the absolute roughness of the pipe, in mm.

[0180] If 上 ≥Re2, it is judged that the fluid in the upstream pump station is in the turbulent complete roughness area, and the corresponding longitudinal resistance coefficient λ1 of the upstream pump station is calculated by the following formula:

[0181]

[0182] Where d is the pipe diameter, in meters;

[0183] e is the absolute roughness of the pipe, in mm.

[0184] Preferably, when using a computer for calculation, when Re1<Re 上 <Re2, that is, when the fluid in the upstream pump station is in the turbulent mixed friction zone, the Colebrook formula can be used to calculate the corresponding along-the-line resistance coefficient λ1 of the upstream pump station; the Colebrook formula is a key equation in fluid mechanics for determining the friction coefficient of fluid flow in a pipeline, which will not be described here; it uses implicit function iterative calculation to make the result more accurate.

[0185] Furthermore, since the resistance coefficient λ2 corresponding to the downstream pump station 2 is related to the corresponding flow state, different flow states correspond to different calculation methods; the step S2-2 also includes step S2-2-2;

[0186] Step S2-2-2: Calculate the Reynolds number Re of the fluid in the downstream pump station 2 by the following formula: 下 :

[0187]

[0188] Where V2 is the flow rate of the fluid in the downstream pump station 2, in m / s;

[0189] d is the pipe diameter, in meters;

[0190] ν is the kinematic viscosity of the fluid, in m 2 / s;

[0191] The lower critical Reynolds number Re1 is calculated by the following formula:

[0192]

[0193] Where d is the pipe diameter, in meters;

[0194] e is the absolute roughness of the pipe, in mm;

[0195] The upper critical Reynolds number Re2 is calculated by the following formula:

[0196]

[0197] Where d is the pipe diameter, in meters;

[0198] e is the absolute roughness of the pipe, in mm;

[0199] The Reynolds number Re of the fluid in the downstream pump station 2 下 Compare with the lower critical Reynolds number Re1 and the upper critical Reynolds number Re2;

[0200] If 下 <2000, it is judged that the fluid in the downstream pump station is in a laminar flow state, and the corresponding flow resistance coefficient λ2 of the downstream pump station is calculated by the following formula:

[0201]

[0202] If 2000≤Re 下 <Re1, it is judged that the fluid in the downstream pump station is in the turbulent hydraulic smooth area;

[0203] And when 2000≤Re下 <10 5 When the downstream pump station has a resistance coefficient λ1, the following formula is used to calculate the resistance coefficient λ1 along the downstream pump station:

[0204]

[0205] When 10 5 <Re 下 When <Re1, the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula:

[0206]

[0207] If Re1≤Re 下 <Re2, it is judged that the fluid in the downstream pump station is in the turbulent mixed friction zone, and the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula:

[0208]

[0209] Where d is the pipe diameter, in meters;

[0210] e is the absolute roughness of the pipe, in mm.

[0211] If 下 ≥Re2, it is judged that the fluid in the downstream pump station is in the turbulent complete roughness area, and the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula:

[0212]

[0213] Where d is the pipe diameter, in meters;

[0214] e is the absolute roughness of the pipe, in mm.

[0215] Preferably, when using a computer for calculation, when Re1<Re 下 <Re2, that is, when the fluid in the downstream pump station is in the turbulent mixed friction zone, the Colebrook formula can be used to calculate the corresponding along-the-line resistance coefficient λ2 of the downstream pump station; the Colebrook formula is a key equation in fluid mechanics for determining the friction coefficient of fluid flow in a pipeline, which will not be described here; it uses implicit function iterative calculation to make the result more accurate.

[0216] Further, in order to specifically realize the calculation of the outlet pressure head h1 of the upstream pumping station 1 and the inlet pressure head h2 of the downstream pumping station 2 by timing and synchronizing the inlet pressure data and the outlet pressure data collected from each pumping station along the pipeline; the step S3 includes step S3-1 and step S3-2;

[0217] Step S3-1: Calculate the outlet pressure h1 of the upstream pump station 1 by the following formula:

[0218]

[0219] In the formula, p 上 It is the outlet pressure data of the upstream pump station 1, in MPa; it is read by setting a pressure sensor at the outlet of the upstream pump station 1;

[0220] ρ is the density of the fluid transported in the pipeline, in kg / m 3 ;

[0221] h 上 is the elevation of the upstream pumping station, in m;

[0222] Step S3-2: Calculate the inlet pressure h2 of the downstream pump station 2 by the following formula:

[0223]

[0224] In the formula, p 下 The inlet pressure data of the downstream pump station 2 is in MPa. It is read by setting a pressure sensor at the inlet of the downstream pump station 2.

[0225] ρ is the density of the fluid transported in the pipeline, in kg / m 3 ;

[0226] h 下 is the elevation of the downstream pumping station, in meters.

[0227] Furthermore, step S1-1 is included between step S1 and step S2;

[0228] Step S1-1: In two pumping stations adjacent to the leakage point, if at the same time, the flow rate of the upstream pumping station 1 increases and the flow rate of the downstream pumping station 2 decreases, it is determined that a leakage occurs between the upstream pumping station 1 and the downstream pumping station 2, and the process proceeds to step S2; otherwise, it is considered that no leakage occurs between the upstream pumping station 1 and the downstream pumping station 2, and step S2 is not performed. Thus, the flow rate data collected by each pumping station along the pipeline is synchronously and regularly used to determine whether there is a leakage, thereby avoiding misjudgment of leakage.

[0229] Furthermore, the positioning method further comprises step S6: jointly calculating the pressure head line equation upstream of the leakage point and the pressure head line equation downstream of the leakage point to obtain the ordinate value of the intersection point, wherein the ordinate value is the pressure head h of the leakage point. 泄 , so that the staff can obtain the pressure head information of the leakage point, which is convenient for subsequent leakage control and repair.

[0230] Preferably, the pressure head h at the leakage point can be 泄The difference between the elevation of the leakage point and the pressure of the leakage point can be used to obtain the leakage situation, so that the staff can take different control and repair measures accordingly.

[0231] The calculation process of the present invention is described below in conjunction with a specific data record:

[0232] The following table shows the elevation data corresponding to the three pumping stations set up along a pipeline, as well as the flow data, inlet pressure data, and outlet pressure data collected at two times:

[0233]

[0234] It is known that the absolute roughness of the conveying pipeline is e = 0.15 mm, and the density of the conveying fluid is ρ = 800 kg / m 3 , kinematic viscosity ν = 2 × 10 -6 m 2 / s;

[0235] Step S1: collect flow data, inlet pressure data and outlet pressure data from each pump station along the pipeline at a regular and synchronous time; the collected records are shown in the table above;

[0236] Step S1-1: At the same time, the flow rate of the second pump station is 40m 3 / h, the flow rate of the three pump stations is 30m 3 / h, it is determined that leakage occurs between pumping station 2 and pumping station 3, and pumping station 2 is defined as the upstream pumping station and pumping station 3 is defined as the downstream pumping station;

[0237] Step S2-1-1: The flow rate V1 of the fluid in the upstream pump station is calculated by the following formula:

[0238]

[0239] Step S2-1-2: Calculate the Reynolds number Re of the fluid in the upstream pump station by the following formula: 上 :

[0240]

[0241] The lower critical Reynolds number Re1 is calculated by the following formula:

[0242]

[0243] The upper critical Reynolds number Re2 is calculated by the following formula:

[0244]

[0245] Among them, Re1<Re 上 <Re2, the corresponding upstream pump station resistance coefficient λ1 is calculated by the following formula:

[0246]

[0247] Step S2-1: Calculate the hydraulic gradient i1 of the upstream pump station by the following formula:

[0248]

[0249] Step S2-2-1: The flow rate V2 of the fluid in the downstream pump station is calculated by the following formula:

[0250]

[0251] Step S2-2-2: Calculate the Reynolds number Re of the fluid in the downstream pump station by the following formula: 下 :

[0252]

[0253] The lower critical Reynolds number Re1 is calculated by the following formula:

[0254]

[0255] The upper critical Reynolds number Re2 is calculated by the following formula:

[0256]

[0257] Among them, Re1<Re 下 <Re2, the corresponding downstream pump station along the resistance coefficient λ2 is calculated by the following formula:

[0258]

[0259] Step S2-1: Calculate the hydraulic gradient i2 of the downstream pump station by the following formula:

[0260]

[0261] Step S3-1: Calculate the outlet pressure h1 of the upstream pump station by the following formula:

[0262]

[0263] Step S3-2: Calculate the inlet pressure h2 of the downstream pump station by the following formula:

[0264]

[0265] Step S4: define the distance length S along the line as the horizontal coordinate in the coordinate system, define the pressure head H along the line as the vertical coordinate in the coordinate system, take the hydraulic gradient i1 of the upstream pumping station as the slope, take the outlet pressure head h1 of the upstream pumping station as the intercept, and establish the pressure head line equation upstream of the leakage point in the above coordinate system;

[0266] In the coordinate system, the fixed point A is drawn with the distance between the downstream pumping station and the upstream pumping station as the horizontal coordinate value and the inlet pressure head h2 of the downstream pumping station as the vertical coordinate value, and the hydraulic gradient i2 of the downstream pumping station is used as the slope. The pressure head line equation downstream of the leakage point is established through the fixed point A.

[0267] In actual use, the distance length S along the upstream pump station is defined as 0, and the pressure head line equation upstream of the leakage point is:

[0268] H=-0.025S+729.6(a)

[0269] It is known that the distance between the downstream pump station and the upstream pump station is 10000m, and the inlet pressure head of the downstream pump station is h2=545.5m. It can be determined that the coordinates of the fixed point A on the pressure head line equation downstream of the leakage point are (10000, 545.5). Through this coordinate value, the pressure head line equation downstream of the leakage point is rewritten into the slope-intercept equation corresponding to the pressure head line equation upstream of the leakage point, that is, the pressure head line equation downstream of the leakage point is:

[0270] H=-0.0145S+690.8(b)

[0271] Plot the function graphs of equations (a) and (b) in the same coordinate system and solve the simultaneous equations (a) and (b) to obtain:

[0272] S=3693

[0273] H=637

[0274] That is: the distance between the leakage point and the upstream pumping station is 3693m, and the pressure head at the leakage point is 637m.

[0275] In summary, the embodiment of the present invention provides a method for locating pipeline leakage, which calculates the hydraulic gradient i1 of the upstream pump station 1 through the flow data of the upstream pump station 1 of the leakage point 3; and calculates the outlet pressure head h1 of the upstream pump station 1 according to the outlet pressure data of the upstream pump station 1; the hydraulic gradient i1 of the upstream pump station 1 represents the ratio between the pressure head size of the fluid in the upstream pump station 1 at various points along the line after the upstream pump station 1 and the distance length between the point and the upstream pump station 1; the hydraulic gradient i1 of the downstream pump station 2 of the leakage point 3 is calculated. The hydraulic gradient i2 of the downstream pump station 2 is calculated according to the inlet pressure data of the downstream pump station 2. The hydraulic gradient i2 of the downstream pump station 2 represents the ratio between the pressure head size at each point along the line and the distance between the point and the downstream pump station 2 before the downstream pump station 2. If there is no leakage between the upstream pump station 1 and the downstream pump station 2, the hydraulic gradient i1 of the upstream pump station 1 should be consistent with the hydraulic gradient i2 of the downstream pump station 2. However, after the leakage occurs, the pressure head changes due to the pipeline leakage. From the leakage point 3, the hydraulic gradient i2 of the downstream pump station 2 changes. The slope will change; a coordinate system is established by taking the length of the distance S along the line as the horizontal coordinate in the coordinate system, defining the pressure head H along the line as the vertical coordinate in the coordinate system, and then taking the hydraulic gradient i1 of the upstream pumping station 1 as the slope, and taking the outlet pressure head h1 of the upstream pumping station 1 as the intercept, an upstream pressure head line equation 100 of the leakage point is established in the coordinate system; the upstream pressure head line equation 100 represents the pressure head size corresponding to each point along the line starting from the upstream pumping station 1; in the same coordinate system, the distance length between the downstream pumping station 2 and the upstream pumping station 1 is the horizontal coordinate value, and the The inlet pressure head h2 of the downstream pump station 2 is used as the ordinate value to draw the fixed point A, and the hydraulic gradient i2 of the downstream pump station is used as the slope, and the downstream pressure head line equation 200 of the leakage point is established through the fixed point A; the horizontal coordinate value of the intersection is calculated by jointly calculating the upstream pressure head line equation 100 of the leakage point and the downstream pressure head line equation 200 of the leakage point, so as to obtain the distance between the leakage point 3 and the upstream pump station 1, and realize the positioning of the leakage point 3, so as to facilitate timely control and subsequent recovery of the leakage, thereby avoiding the loss and waste of a large amount of fluid due to leakage due to failure to timely control and repair the leakage.

[0276] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for locating a pipeline leak, characterized in that: The following steps are involved: Step S1: synchronously and regularly collect flow data, inlet pressure data and outlet pressure data from each pump station along the pipeline; Step S2: define two pumping stations adjacent to the leakage point as an upstream pumping station and a downstream pumping station along the pipeline transportation direction; read the flow data of the upstream pumping station and calculate the hydraulic gradient i1 of the upstream pumping station; read the flow data of the downstream pumping station and calculate the hydraulic gradient i2 of the downstream pumping station; Step S3: reading the outgoing pressure data of the upstream pump station, and calculating the outgoing pressure head h1 of the upstream pump station; reading the incoming pressure data of the downstream pump station, and calculating the incoming pressure head h2 of the downstream pump station; Step S4: define the distance length S along the line as the horizontal coordinate in the coordinate system, define the pressure head H along the line as the vertical coordinate in the coordinate system, take the hydraulic gradient i1 of the upstream pumping station as the slope, take the outlet pressure head h1 of the upstream pumping station as the intercept, and establish the pressure head line equation upstream of the leakage point in the above coordinate system; In the coordinate system, a fixed point A is drawn with the distance between the downstream pump station and the upstream pump station as the horizontal coordinate value, the inlet pressure head h2 of the downstream pump station as the vertical coordinate value, and the hydraulic gradient i2 of the downstream pump station is used as the slope, and the pressure head line equation downstream of the leakage point is established through the fixed point A; Step S5: Combine the pressure head line equation upstream of the leakage point and the pressure head line equation downstream of the leakage point to calculate the horizontal coordinate value of the intersection point, which is the distance between the leakage point and the upstream pump station, to determine the location of the leakage point.

2. The positioning method according to claim 1, characterized in that: Step S2 includes step S2-1 and step S2-2; Step S2-1: Calculate the hydraulic gradient i1 of the upstream pump station by the following formula: Where λ1 is the resistance coefficient along the upstream pump station; V1 is the flow rate of the fluid in the upstream pump station, in m / s; d is the pipe diameter, in meters; g is the acceleration due to gravity, which is 9.8 m / s 2 ; Step S2-2: Calculate the hydraulic gradient i2 of the downstream pump station by the following formula: Where λ2 is the resistance coefficient along the downstream pump station; V2 is the flow rate of the fluid in the downstream pump station, in m / s; d is the pipe diameter, in meters; g is the acceleration due to gravity, which is 9.8 m / s 2 .

3. The positioning method according to claim 2, characterized in that: Step S2-1 also includes step S2-1-1; Step S2-1-1: The flow rate V1 of the fluid in the upstream pump station is calculated by the following formula: Where q1 is the flow rate of the upstream pump station, in m 3 / h; π is the ratio of the circumference of a circle, which is 3.14; d is the pipe diameter, in meters; The flow rate q1 of the upstream pump station is obtained by setting a flow meter in the upstream pump station to measure the flow rate data of the upstream pump station; Step S2-2 also includes step S2-2-1; Step S2-2-1: The flow rate V2 of the fluid in the downstream pump station is calculated by the following formula: Where q2 is the flow rate of the downstream pump station, in m 3 / h; π is the ratio of the circumference of a circle, which is 3.14; d is the pipe diameter, in meters; The flow rate q2 of the downstream pumping station is obtained by setting a flow meter in the downstream pumping station to measure the flow data of the downstream pumping station.

4. The positioning method according to claim 3, characterized in that: The step S2-1 also includes step S2-1-2, Step S2-1-2: Calculate the Reynolds number Re of the fluid in the upstream pump station by the following formula: 上 : Where V1 is the flow rate of the fluid in the upstream pump station, in m / s; d is the pipe diameter, in meters; ν is the kinematic viscosity of the fluid, in m 2 / s; The lower critical Reynolds number Re1 is calculated by the following formula: Where d is the pipe diameter, in meters; e is the absolute roughness of the pipe, in mm; The upper critical Reynolds number Re2 is calculated by the following formula: Where d is the pipe diameter, in meters; e is the absolute roughness of the pipe, in mm; The Reynolds number Re of the fluid in the upstream pump station 上 Compare with the lower critical Reynolds number Re1 and the upper critical Reynolds number Re2; If 上 <2000, it is judged that the fluid in the upstream pump station is in a laminar flow state, and the corresponding flow resistance coefficient λ1 of the upstream pump station is calculated by the following formula: If 2000≤Re 上 <Re1, it is judged that the fluid in the upstream pump station is in the turbulent hydraulic smooth area, and when 2000≤Re 上 <10 5 When , the corresponding upstream pump station along the resistance coefficient λ1 is calculated by the following formula: When 10 5 <Re 上 When <Re1, the corresponding resistance coefficient λ1 of the upstream pump station is calculated by the following formula: If Re1≤Re 上 <Re2, it is judged that the fluid in the upstream pump station is in the turbulent mixed friction zone, and the corresponding resistance coefficient λ1 of the upstream pump station is calculated by the following formula: Where d is the pipe diameter, in meters; e is the absolute roughness of the pipe, in mm. If 上 ≥Re2, it is judged that the fluid in the upstream pump station is in the turbulent complete roughness area, and the corresponding longitudinal resistance coefficient λ1 of the upstream pump station is calculated by the following formula: Where d is the pipe diameter, in meters; e is the absolute roughness of the pipe, in mm.

5. The positioning method according to claim 3, characterized in that: The step S2-2 also includes step S2-2-2; Step S2-2-2: Calculate the Reynolds number Re of the fluid in the downstream pump station by the following formula: 下 : Where V2 is the flow rate of the fluid in the downstream pump station, in m / s; d is the pipe diameter, in meters; ν is the kinematic viscosity of the fluid, in m 2 / s; The lower critical Reynolds number Re1 is calculated by the following formula: Where d is the pipe diameter, in meters; e is the absolute roughness of the pipe, in mm; And the upper critical Reynolds number Re2 is calculated by the following formula: Where d is the pipe diameter, in meters; e is the absolute roughness of the pipe, in mm; The Reynolds number Re of the fluid in the downstream pump station 下 Compare with the lower critical Reynolds number Re1 and the upper critical Reynolds number Re2; If 下 <2000, it is judged that the fluid in the downstream pump station is in a laminar flow state, and the corresponding flow resistance coefficient λ2 of the downstream pump station is calculated by the following formula: If 2000≤Re 下 <Re1, it is judged that the fluid in the downstream pump station is in the turbulent hydraulic smooth area; And when 2000≤Re 下 <10 5 When the downstream pump station has a resistance coefficient λ1, the following formula is used to calculate the resistance coefficient λ1 along the downstream pump station: When 10 5 <Re 下 When <Re1, the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula: If Re1≤Re 下 <Re2, it is judged that the fluid in the downstream pump station is in the turbulent mixed friction zone, and the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula: Where d is the pipe diameter, in meters; e is the absolute roughness of the pipe, in mm. If 下 ≥Re2, it is judged that the fluid in the downstream pump station is in the turbulent complete roughness area, and the corresponding resistance coefficient λ2 of the downstream pump station is calculated by the following formula: Where d is the pipe diameter, in meters; e is the absolute roughness of the pipe, in mm.

6. The positioning method according to claim 1, characterized in that: The step S3 includes step S3-1 and step S3-2; Step S3-1: Calculate the outlet pressure h1 of the upstream pump station by the following formula: In the formula, p 上 It is the outlet pressure data of the upstream pump station, in MPa; it is read by setting a pressure sensor at the outlet of the upstream pump station; ρ is the density of the fluid transported in the pipeline, in kg / m 3 ; h 上 is the elevation of the upstream pumping station, in meters; Step S3-2: Calculate the inlet pressure h2 of the downstream pump station by the following formula: In the formula, p 下 It is the inlet pressure data of the downstream pump station, in MPa; it is read by setting a pressure sensor at the inlet of the downstream pump station; ρ is the density of the fluid transported in the pipeline, in kg / m 3 ; h 下 is the elevation of the downstream pumping station, in meters.

7. The positioning method according to claim 1, characterized in that: Step S1-1 is also included between step S1 and step S2; Step S1-1: In two pumping stations adjacent to the leakage point, if at the same time, the flow rate of the upstream pumping station increases and the flow rate of the downstream pumping station decreases, it is determined that a leakage occurs between the upstream pumping station and the downstream pumping station, and step S2 is continued; otherwise, it is considered that no leakage occurs between the upstream pumping station and the downstream pumping station, and step S2 is not performed.

8. The positioning method according to claim 1, characterized in that: Also includes: Step S6: Combine the pressure head line equation upstream of the leak point and the pressure head line equation downstream of the leak point to find the ordinate value of the intersection point. The ordinate value is the pressure head h of the leak point. 泄 .

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