Pipeline water hammer experimental device and experimental method and water hammer prediction model establishment method

Abstract

The present invention discloses a pipeline water hammer experimental device, comprising a pipeline and a detection assembly arranged on the pipeline, wherein the pipeline comprises a connecting section, a liquid column forming section, and a detection section connected in sequence, wherein the horizontal height of the liquid column forming section is lower than the connecting section and the detection section, and the liquid column forming section comprises a first connecting pipe, a second connecting pipe, and a liquid column pipe, wherein the first connecting pipe is connected to the connecting section, the second connecting pipe is connected to the detection section, and the liquid column pipe is connected between the first connecting pipe and the second connecting pipe; the liquid column pipe comprises a plurality of first pipe units connected in sequence, and the detection section comprises a plurality of second pipe units connected in sequence; the detection assembly is used to detect the temperature, pressure, speed, pressure change, and pipeline pressure drop during the movement of the liquid column. The pipeline water hammer experimental device of the present invention can use high-temperature steam to drive the liquid column to move, accurately reproducing the movement state of the liquid mass in a real steam pipeline.

Description

Technical Field

[0001] The present invention specifically relates to a pipeline water hammer experimental device, a method for conducting a pipeline water hammer experiment based on the experimental device, and a method for establishing a pipeline water hammer prediction model. Background Art

[0002] Pipeline systems are widely used in the power, chemical, and oil extraction and transportation industries. In high-pressure steam pipeline systems, when equipment is shut down due to pipeline maintenance or failure, condensate can collect in low-lying areas of the pipeline and in front of valves. When the system is restarted, the valve suddenly opens, and the liquid in the pipeline continuously accelerates under the driving pressure, forming a high-speed liquid column segment (liquid mass) that moves downstream in the pipeline. When this high-speed liquid column strikes components such as valves, orifice plates, and elbows in the pipeline, it generates tremendous impact force and systemic pressure fluctuations, a phenomenon known as water hammer. Severe water hammer can damage the pipeline system.

[0003] When protecting steam pipelines from the pressure fluctuations caused by water hammer, the key issue is how to accurately simulate and predict the occurrence of water hammer within steam pipelines. Traditional water hammer experimental devices and prediction methods fail to account for the high temperature of high-pressure steam, the shedding of liquid at the tail of the liquid slug during its movement within the steam pipeline, and the pressure drop of the driving gas at the tail of the liquid slug. This leads to certain deviations in the simulation and prediction of water hammer in high-temperature steam pipelines, and their limited accuracy in reproducing actual operating conditions, making it impossible to provide accurate theoretical guidance for actual engineering design and implementation. Summary of the Invention

[0004] In view of this, the present invention provides a pipeline water hammer experimental device and a prediction method based on the experimental device.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A pipeline water hammer experimental device includes a pipeline and a detection assembly arranged on the pipeline, the pipeline includes a connecting section, a liquid column forming section, and a detection section connected in sequence, the horizontal height of the liquid column forming section is lower than the connecting section and the detection section, the liquid column forming section includes a first connecting pipe, a second connecting pipe, and a liquid column pipe, the first connecting pipe is connected to the connecting section, the second connecting pipe is connected to the detection section, and the liquid column pipe is connected between the first connecting pipe and the second connecting pipe; the liquid column pipe includes a plurality of first pipe units connected in sequence, and the detection section includes a plurality of second pipe units connected in sequence; the detection assembly is used to detect temperature, pressure, speed, pressure change and pipeline pressure drop during the movement of the liquid column.

[0007] According to some preferred embodiments of the present invention, the detection assembly includes one or more of a pressure detection mechanism, a capacitance tomography sensor, an ultrasonic Doppler testing mechanism, and a capacitance velocimetry mechanism; the capacitance tomography sensor, ultrasonic Doppler testing mechanism, and capacitance velocimetry mechanism are disposed on the detection section. The ultrasonic Doppler testing mechanism includes an ultrasonic Doppler sensor, a pressure sensor, and a temperature sensor.

[0008] According to some preferred embodiments of the present invention, the pressure detection mechanism is used to measure the pressure changes and pipeline pressure drop during the movement of the liquid column segment; the capacitance tomography sensor, ultrasonic Doppler testing mechanism and capacitance speed measurement mechanism are used to capture the temperature, pressure and speed of the liquid column in the pipeline during the movement.

[0009] According to some preferred embodiments of the present invention, the pressure detection mechanism includes a pressure gauge, a pressure-stabilizing tank and a pressure-guiding pipe connected between the pressure gauge and the pipeline. The pressure-guiding pipe is U-shaped, the pressure-stabilizing tank is arranged between one end of the pressure-guiding pipe and the pipeline, and the pressure gauge is arranged at the other end of the pressure-guiding pipe. The horizontal height of the pressure gauge is lower than the horizontal height of the pressure-stabilizing tank.

[0010] According to some preferred embodiments of the present invention, the pressure detection mechanism includes a first pressure detection mechanism arranged on the connecting section, a second pressure detection mechanism arranged on the liquid column pipeline, and a third pressure detection mechanism, a fourth pressure detection mechanism, a fifth pressure detection mechanism, a sixth pressure detection mechanism, and a seventh pressure detection mechanism arranged in sequence on the detection section.

[0011] According to some preferred implementation aspects of the present invention, the first connecting pipe and the second connecting pipe are arranged in a vertical direction, and the liquid column pipe is arranged in a horizontal direction.

[0012] According to some preferred implementation aspects of the present invention, a water inlet is provided on the first connecting pipe; a drain outlet is provided on the liquid column pipe; and a liquid level gauge is provided on the liquid column forming section.

[0013] According to some preferred embodiments of the present invention, the connecting section includes a front section pipeline and a pneumatic valve and a manual valve arranged on the front section pipeline; the connecting section connects the high-pressure steam source and the liquid column forming section.

[0014] The present invention also provides a method for conducting a pipeline water hammer test based on the above-mentioned experimental device, comprising the following steps:

[0015] Conduct airtightness inspection and calibration of experimental equipment;

[0016] injecting water into the pipeline of the liquid column forming section to form an initial liquid column;

[0017] Open the pneumatic valve and manual valve on the front section of the pipeline to release high-pressure steam and generate water hammer phenomenon;

[0018] Close the pneumatic valves and manual valves on the front section of the pipeline and collect data from each detection component;

[0019] Open the pneumatic valve and manual valve on the front section of the pipeline to release the residual pressure in the pipeline, and the single test is completed;

[0020] Replace the number of first pipe units on the liquid column pipe and / or the number of second pipe units on the detection section, adjust the parameters, repeat the above steps and collect corresponding data to conduct water hammer experiments under different working conditions.

[0021] According to some preferred embodiments of the present invention, the parameters include the length of the initial liquid column, the temperature of the driving steam, and the pressure of the driving steam.

[0022] The present invention also provides a method for establishing a pipeline water hammer prediction model, comprising the following steps:

[0023] According to the friction of the pipe wall and the mass shedding along the slug, the motion equation of the liquid column is obtained:

[0024]

[0025] Where v is the velocity of the liquid column, F 0t is the upstream driving pressure, F wt is the wall friction, θ is the pipe installation angle of the detection section, m t is the mass of the liquid column;

[0026] The movement distance S of the liquid column t The relationship with speed is shown as follows:

[0027] S t =∫0 t v dt

[0028] Assuming that the driving pressure decreases linearly with time, the driving pressure at the tail of the liquid column is:

[0029]

[0030] In the formula, the rate of change is K p , determined by the experimental data above, D is the pipe diameter, t is the time, and F0 is the driving pressure of steam;

[0031] The wall friction can be expressed by the shear stress τ:

[0032] F wt =τL t πD

[0033] The length of the liquid column Lt The functional relationship is:

[0034] L t =L0-βS t

[0035] Where β is an empirical coefficient, which is determined by experimental testing of the pipeline water hammer test device.

[0036] According to some preferred embodiments of the present invention, the mass m of the liquid column segment is t Calculated by the following formula:

[0037] m t =πD 2 ρL t / 4

[0038] D is the pipe diameter, L is t is the length of the liquid column, ρ is the liquid density of the liquid column, and the subscript t represents the variable at different time points.

[0039] According to some preferred embodiments of the present invention, the wall shear stress τ is calculated by the following formula:

[0040]

[0041] Where C r is the wall friction coefficient.

[0042] According to some preferred embodiments of the present invention, the wall friction coefficient C r Calculated by the following formula:

[0043]

[0044] Where, Reynolds number μ is the dynamic viscosity coefficient of the fluid.

[0045] According to some preferred embodiments of the present invention, the impact pressure F P Calculated by the following formula:

[0046] F P =0.3ρv 2

[0047] Where ρ is the liquid density of the liquid column, and v is the velocity of the liquid column.

[0048] Due to the adoption of the above technical solution, compared with the existing technology, the benefits of the present invention are as follows: the pipeline water hammer experimental device of the present invention can use high-temperature steam to drive the movement of the liquid column and accurately restore the movement state of the liquid mass in the actual steam pipeline; match the collected data of each detection component to establish a water hammer prediction model, conduct a thorough study on the liquid falling off the tail of the liquid mass and the pressure drop of the driving gas at the tail of the liquid mass, propose a deterministic water hammer occurrence condition judgment criterion and a calculation method for the impact force of the liquid mass, thereby improving the accuracy of water hammer prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 Schematic diagram of the structure of a pipeline water hammer experimental device in a preferred embodiment of the present invention;

[0051] Figure 2 A schematic structural diagram of a pressure detection mechanism in a preferred embodiment of the present invention;

[0052] In the accompanying drawings, there are connecting section 1, liquid column forming section 2, first connecting pipe 21, second connecting pipe 22, first pipe unit 23, water injection port 25, drain port 26, liquid level gauge 27, detection section 3, second pipe unit 31, first pressure detection mechanism 41, second pressure detection mechanism 42, third pressure detection mechanism 43, fourth pressure detection mechanism 44, fifth pressure detection mechanism 45, sixth pressure detection mechanism 46, seventh pressure detection mechanism 47, capacitance tomography sensor 5, ultrasonic Doppler test mechanism 6, capacitance speed measurement mechanism 7, pressure regulating tank 81, pressure guiding pipe 82, manual valve 83, pressure gauge 84, water receiving box 9, exhaust pipe 10. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0054] The present invention comprises a steam pipeline water hammer experimental device and a method for establishing a steam pipeline water hammer prediction model. In the device, the gas driving the liquid column is replaced with high-temperature steam, accurately reproducing the motion state of the liquid column segment in a real steam pipeline. In the prediction method, numerical simulation is used to thoroughly study and analyze the liquid shedding at the tail of the liquid column segment and the pressure drop of the driving gas at the tail of the liquid column segment, thereby improving the accuracy of water hammer prediction. Furthermore, during measurement, the liquid column segment velocity measured by capacitance velocimetry is cross-verified with the water hammer pressure measured by a pressure detection mechanism, enhancing the feasibility and accuracy of the experiment.

[0055] Example 1 Pipeline water hammer experimental device

[0056] like Figure 1 and 2 As shown, the pipeline water hammer experimental device of this embodiment includes a pipeline and a detection component arranged on the pipeline. The pipeline includes a connecting section 1, a liquid column forming section 2, and a detection section 3 connected in sequence. The horizontal height of the liquid column forming section 2 is lower than the connecting section 1 and the detection section 3. The connecting section 1 includes a front section pipeline and a pneumatic valve and a manual valve (not shown in the figure) arranged on the front section pipeline; the connecting section 1 connects the upstream high-pressure steam source (pressure ≥ 0.6MPa; temperature ≥ 150°C) and the liquid column forming section 2. There is a reducing pipe on the front section pipeline, which can be applied to pipeline devices of different diameters. An elbow pipe is arranged after the reducing pipe to connect the front section pipeline and the liquid column forming section 2. The radius of the elbow pipe is 1.5 times the diameter of the pipeline. A plurality of detection components are arranged on the downstream pipeline after the manual valve.

[0057] The detection assembly is used to detect the temperature, pressure, velocity, pressure changes, and pipeline pressure drop during the movement of the liquid column. Specifically, the detection assembly includes a pressure detection mechanism, a capacitance tomography sensor 5 (ECT), an ultrasonic Doppler testing mechanism 6 (including an ultrasonic Doppler sensor UD, a pressure sensor, and a temperature sensor), and a capacitance velocity measurement mechanism 7. The capacitance tomography sensor 5, ultrasonic Doppler sensor, and capacitance velocity measurement mechanism 7 are arranged on the detection section 3 and directly inside the pipeline.

[0058] The pressure detection mechanism accurately measures the changes in pressure P during the movement of the liquid column and the pressure drop in the pipeline. The ECT and ultrasonic Doppler testing mechanisms capture the temperature T (measured by a temperature sensor) and pressure P (measured by a pressure sensor) of the liquid column in the pipeline during its movement. The ultrasonic Doppler sensor UD and the capacitance velocimetry device capture the velocity v of the liquid column in the pipeline during its movement. The liquid column velocity measured by capacitance velocimetry is cross-validated with the pressure measured by the pressure detection mechanism, improving the feasibility and accuracy of the experiment. Furthermore, the data measured in the experiment can be used to modify the parameters of the water hammer prediction model, thereby improving the accuracy of the water hammer prediction method.

[0059] The liquid column formation section 2 is generally U-shaped and includes a first connecting pipe 21, a second connecting pipe 22, and a liquid column pipe. The first connecting pipe 21 is connected to the connection section 1, and the second connecting pipe 22 is connected to the detection section 3. The liquid column pipe is connected between the first connecting pipe 21 and the second connecting pipe 22. The first connecting pipe 21 and the second connecting pipe 22 are arranged in a vertical direction, the liquid column pipe is arranged in a horizontal direction, and the detection section 3 is arranged horizontally and has an installation angle θ. The first connecting pipe 21 is provided with a water inlet 25; the liquid column pipe is provided with a drain outlet 26; and the liquid column formation section 2 is provided with a liquid level gauge 27, which can observe and control the length of the initial liquid column.

[0060] The liquid column pipeline includes a plurality of first pipeline units 23 connected in sequence. The plurality of detachably connected first pipeline units 23 are used to form initial liquid columns of different lengths. The detection section 3 includes a plurality of second pipeline units 31 connected in sequence. By changing the number of first pipeline units 23 and / or second pipeline units 31, different experimental parameters can be matched to conduct experiments under different working conditions. A water receiving box 9 and an exhaust pipe 10 are provided at the tail end of the detection section 3. A bend is provided between the second pipeline unit 31 and the water receiving box 9, and a pressure detection mechanism is provided at the bend.

[0061] The pressure detection mechanism includes a pressure gauge 84, a pressure-stabilizing tank 81 connected between the pressure gauge 84 and the pipeline, a pressure-conducting pipe 82, and a manual valve 83. The pressure-conducting pipe 82 is U-shaped, the pressure-stabilizing tank 81 is set between one end of the pressure-conducting pipe 82 and the pipeline, and the pressure gauge 84 is set at the other end of the pressure-conducting pipe 82. The horizontal height of the pressure gauge 84 is lower than the horizontal height of the pressure-stabilizing tank 81. The pressure-stabilizing tank 81 is connected to the pipeline and is filled with liquid. The liquid in the pressure-stabilizing tank 81 can isolate the pressure gauge 84 from the high-temperature steam, preventing the high-temperature steam from damaging the pressure gauge 84. The pressure-conducting pipe 82 can transmit the pressure generated inside the pipeline, and the pressure gauge 84 can measure the corresponding internal pressure. The manual valve 83 can control the working state of the pressure-stabilizing tank 81. At the same time, the manual valve 83 can be closed before the experiment begins to facilitate the filling of liquid into the pressure-stabilizing tank 81.

[0062] The pressure detection mechanism includes a first pressure detection mechanism 41 provided on the connecting section 1, a second pressure detection mechanism 42 provided on the liquid column pipeline, and a third pressure detection mechanism 43, a fourth pressure detection mechanism 44, a fifth pressure detection mechanism 45, a sixth pressure detection mechanism 46, and a seventh pressure detection mechanism 47 provided in sequence on the detection section 3. The third pressure detection mechanism 43 and the seventh pressure detection mechanism 47 are provided at the head and tail of the detection section 3, respectively. The pressure detection mechanism measures the pressure at the corresponding point of the liquid column as it moves within the pipeline. The pressure measurement at different experimental positions of the liquid column section is used for recording and calculation.

[0063] Example 2 Pipeline Water Hammer Test Method

[0064] This embodiment provides a method for conducting a pipeline water hammer experiment based on the experimental apparatus in Example 1, which mainly includes the following steps:

[0065] Conduct airtightness inspection and calibration of experimental equipment;

[0066] injecting water into the pipe of liquid column forming section 2 to form an initial liquid column;

[0067] Open the pneumatic valve and manual valve on the front section of the pipeline to release high-pressure steam (driving steam) and generate water hammer phenomenon;

[0068] Close the pneumatic valves and manual valves on the front section of the pipeline and collect data from each detection component;

[0069] Open the pneumatic valve and manual valve on the front section of the pipeline to release the residual pressure in the pipeline, and the single test is completed;

[0070] Replace the number of first pipe units 23 on the liquid column pipeline and / or the number of second pipe units 31 on the detection section 3, adjust parameters such as the initial liquid column length, the temperature of the driving steam, and the pressure of the driving steam, repeat the above steps and collect corresponding data to conduct water hammer experiments under different working conditions.

[0071] Specifically, the pipeline water hammer test method in this embodiment includes the following steps:

[0072] Step 1: Before the experiment begins, close the pneumatic valve and manual valve upstream of the device, fill the device with air at a certain pressure, and measure the pressure of the filling gas using the pressure gauge 84. Keep the pressure in the device from dropping within half an hour to ensure the sealing of the device.

[0073] Step 2: Calibrate each detection component in the device with full tube, half tube and empty tube to verify the consistency of each detection component and improve the accuracy of the experiment.

[0074] Step 3: At the beginning of the experiment, open all valves except the upstream manual valve, pneumatic valve and the drain valve 26 of the liquid column forming section 2, and fill the liquid column forming section 2 with the corresponding volume of liquid through the water injection port 25 to form the initial liquid column L.

[0075] Then, the water injection port 25 is closed, and the upstream manual valve and the pneumatic valve are opened in sequence to release high-pressure steam, causing water hammer.

[0076] Quickly close the pneumatic valve, then the manual valve, and record the data from each test component. This data includes the driving steam pressure F0, measured by the steam source (steam storage tank) pressure gauge 84; the pressure P at each measuring point, measured by the pressure detection mechanism or pressure sensor; the temperature T, measured by the temperature sensor in the ultrasonic Doppler test mechanism 6; and the velocity v of the liquid column, measured by the ultrasonic Doppler sensor UD and the capacitance velocity measurement mechanism 7. These data can be mutually verified.

[0077] After the water hammer phenomenon occurs, open the pneumatic valve to release the residual pressure in front of the pneumatic valve, and the single experiment is completed.

[0078] Step 4: Replace the first pipe unit 23 of the liquid column pipeline in liquid column formation section 2 and the second connecting pipe 22 of detection section 3. Adjust the initial liquid column length L, driving steam temperature T, and driving steam pressure F0. Repeat steps 2 and 3 to conduct water hammer experiments under different operating conditions. The experimental data obtained can be used to modify the parameters in the water hammer prediction model, thereby improving the accuracy of the water hammer prediction method.

[0079] Example 3: Method for Establishing a Pipeline Water Hammer Prediction Model

[0080] This embodiment provides a method for establishing a pipeline water hammer prediction model, comprising the following steps:

[0081] According to the friction force of the pipe wall and the mass shedding of the slug (liquid column) along the way, the motion equation of the liquid column is obtained as follows:

[0082]

[0083] Where v is the velocity of the liquid column segment, which is measured by the ultrasonic Doppler sensor UD and the capacitance velocity measurement mechanism, and F 0t is the driving pressure of upstream steam, F wt is the wall friction, θ is the installation inclination angle of the detection section pipeline, m t is the mass of the liquid column, which is calculated as follows:

[0084] m t =πD 2 ρL t / 4

[0085] Where D is the pipe diameter, L is t is the length of the liquid column segment, ρ is the density of the liquid in the liquid column segment, and the subscript t represents the variable at different time points. Note that because the pipe outlet is open, the resistance caused by the compressed air at the front of the liquid column is very small when the liquid column segment moves at high speed and can be ignored.

[0086] Movement distance S of the liquid column segment t The relationship with speed is:

[0087] S t=∫0 t v dt (2)

[0088] Assume that the driving pressure decreases linearly with time, and the rate of change is K p , determined by the data measured in the above experiment, specifically by recording the change of the steam source (steam tank) pressure value over time and then obtaining the change rate.

[0089] Then the driving pressure at the tail of the liquid column is:

[0090]

[0091] The wall friction can be expressed by the shear stress τ as shown below:

[0092] F wt =τL t πD (4)

[0093] The wall shear stress can be given by:

[0094]

[0095] Among them, C r is the wall friction coefficient, which is calculated by the following formula:

[0096]

[0097] Among them, the Reynolds number μ is the dynamic viscosity coefficient of the fluid.

[0098] Liquid column length L t The functional relationship is:

[0099] L t =L0-βS t (7)

[0100] Among them, β is the empirical coefficient, which is determined based on the calibration results before the experiment and the results of multiple field experimental data.

[0101] According to the above liquid column length L t The calculation formula and field experimental results show that under the conditions of this experimental device, when the movement distance of the liquid column segment is greater than 5 times the initial length of the liquid column, the liquid column segment will be completely broken due to the shedding of the tail liquid.

[0102] Liquid column impact pressure (i.e. water hammer impact pressure) F P It can be given by the following formula:

[0103] F P =0.3ρv 2 (8)

[0104] By the impact pressure FP From the calculation formula, it can be seen that when the liquid density ρ is less than 200kg / m 3 When the water hammer is strong, the impact pressure generated by the water hammer is small, the impact phenomenon is not obvious, and the liquid density will gradually decrease with the decrease of the water content of the section.

[0105] Therefore, when the movement distance S t Less than 5 times the length of the initial liquid column or the liquid density ρ is greater than 200 kg / m 3 When , it is predicted that water hammer will occur at the downstream elbow of the seventh pressure detection mechanism, otherwise it is predicted that water hammer will not occur at the elbow. When water hammer is predicted to occur, it is iterated according to formulas (2) to (7). When the liquid column moves a distance S t The moment when the distance between the measuring section and the elbow is greater than the moment when the water hammer occurs, the velocity v at this moment is substituted into formula (8) to obtain the water hammer impact pressure F P .

[0106] The technical solution of the present invention replaces the gas that drives the movement of the liquid mass (in this device, the liquid column segment) with high-temperature steam in the device, which can accurately restore the movement state of the liquid mass in the actual steam pipe; in terms of the prediction method, through a method that combines theoretical calculation models with experimental test data calibration, the pressure drop of the liquid falling off the tail of the liquid mass and the driving gas at the tail of the liquid mass are fully studied, and a deterministic water hammer occurrence condition judgment criterion and a calculation method for the impact force of the liquid mass are proposed, thereby improving the accuracy of water hammer prediction.

[0107] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for establishing a pipeline water hammer prediction model, characterized in that: The steps include: According to the friction of the pipe wall and the mass shedding along the slug, the motion equation of the liquid column is obtained: Where v is the velocity of the liquid column, F 0t is the driving pressure of steam, F wt is the wall friction, θ is the pipe installation angle of the detection section, m t is the mass of the liquid column; The movement distance S of the liquid column t The relationship with speed is shown as follows: Assuming that the driving pressure decreases linearly with time, the driving pressure at the tail of the liquid column is: Where K p is the rate of change, D is the pipe diameter, t is the time, and F0 is the driving pressure of steam; The wall friction can be expressed by the shear stress τ: F wt =τL t pD The length of the liquid column is L t The functional relationship is: L t =L0-βS t Wherein, β is an empirical coefficient determined by experimental testing of a pipeline water hammer experimental device; the pipeline water hammer experimental device comprises a pipeline and a detection assembly arranged on the pipeline, the pipeline comprises a connecting section, a liquid column forming section, and a detection section connected in sequence, the horizontal height of the liquid column forming section is lower than the connecting section and the detection section, the liquid column forming section comprises a first connecting pipe, a second connecting pipe, and a liquid column pipe, the first connecting pipe is connected to the connecting section, the second connecting pipe is connected to the detection section, and the liquid column pipe is connected between the first connecting pipe and the second connecting pipe; the liquid column pipe comprises a plurality of first pipe units connected in sequence, and the detection section comprises a plurality of second pipe units connected in sequence; the detection assembly is used to detect temperature, pressure, velocity, pressure change, and pipeline pressure drop during the movement of the liquid column; The detection assembly includes one or more of a pressure detection mechanism, a capacitance tomography sensor, an ultrasonic Doppler testing mechanism, and a capacitance velocimetry mechanism; the capacitance tomography sensor, the ultrasonic Doppler testing mechanism, and the capacitance velocimetry mechanism are disposed on the detection section; the velocity of the liquid column segment measured by the capacitance velocimetry and the pressure of the liquid column segment measured by the pressure detection mechanism are mutually verified to improve the feasibility and accuracy of the experiment; at the same time, the data measured in the experiment can be used to correct the parameters in the water hammer prediction method model, thereby improving the accuracy of the water hammer prediction method model; The pressure detection mechanism is used to measure the pressure change of the liquid column segment during movement and the pipeline pressure drop; the capacitance tomography sensor, ultrasonic Doppler testing mechanism and capacitance velocity measurement mechanism are used to capture the temperature, pressure and velocity of the liquid column in the pipeline during movement; the ultrasonic Doppler testing mechanism includes an ultrasonic Doppler sensor, a pressure sensor and a temperature sensor; Change rate K p Determined by the data measured in the following steps: Conduct air tightness inspection and calibration of pipeline water hammer test equipment; injecting water into the pipeline of the liquid column forming section to form an initial liquid column; Open the pneumatic valve and manual valve on the front section of the pipeline to release high-pressure steam and generate water hammer phenomenon; Close the pneumatic valves and manual valves on the front section of the pipeline and collect data from each detection component; Open the pneumatic valve and manual valve on the front section of the pipeline to release the residual pressure in the pipeline, and the single test is completed; Adjust the number of first pipe units on the liquid column pipe and / or the number of second pipe units on the detection section, adjust the parameters, repeat the above steps and collect corresponding data to conduct water hammer experiments under different working conditions.

2. The establishment method according to claim 1, characterized in that The pressure detection mechanism includes a pressure gauge, a pressure-stabilizing tank and a pressure-guiding pipe connected between the pressure gauge and the pipeline. The pressure-guiding pipe is U-shaped, the pressure-stabilizing tank is arranged between one end of the pressure-guiding pipe and the pipeline, and the pressure gauge is arranged at the other end of the pressure-guiding pipe. The horizontal height of the pressure gauge is lower than the horizontal height of the pressure-stabilizing tank.

3. The establishment method according to claim 1 or 2, characterized in that: The pressure detection mechanism includes a first pressure detection mechanism arranged on the connecting section, a second pressure detection mechanism arranged on the liquid column pipeline, and a third pressure detection mechanism, a fourth pressure detection mechanism, a fifth pressure detection mechanism, a sixth pressure detection mechanism, and a seventh pressure detection mechanism arranged in sequence on the detection section.

4. The establishment method according to claim 1, characterized in that The first connecting pipe and the second connecting pipe are arranged in a vertical direction, and the liquid column pipe is arranged in a horizontal direction.

5. The establishment method according to claim 4, characterized in that: A water inlet is provided on the first connecting pipe; a water outlet is provided on the liquid column pipe; and a liquid level gauge is provided on the liquid column forming section.

6. The establishment method according to claim 4, characterized in that: The connecting section includes a front section pipeline and a pneumatic valve and a manual valve arranged on the front section pipeline; the connecting section is connected to the high-pressure steam source and the liquid column forming section.

7. The establishment method according to claim 1, characterized in that: The parameters include the initial liquid column length, the temperature of the driving steam, and the pressure of the driving steam.

8. The establishment method according to claim 1, characterized in that: The mass of the liquid column segment m t Calculated by the following formula: m t =πD 2 ρL t / 4 Where D is the pipe diameter, L is t is the length of the liquid column, ρ is the liquid density of the liquid column, and the subscript t represents the variable at different time points.

9. The establishment method according to claim 1, characterized in that: The wall shear stress τ is calculated by the following formula: Where C r is the wall friction coefficient.

10. The establishment method according to claim 9, characterized in that: Wall friction coefficient C r Calculated by the following formula: Where, Reynolds number μ is the dynamic viscosity coefficient of the fluid.

11. The establishment method according to claim 1, characterized in that: The impact pressure F of the liquid column P Calculated by the following formula: F P =0.3ρv 2 Where ρ is the liquid density of the liquid column, and v is the velocity of the liquid column.

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