A pipeline slug motion and impact experimental system

Abstract

The invention relates to a pipeline slug movement and impact test system, which is characterized by comprising an inlet section, a U-shaped pipe section, a slug horizontal movement section and an experimental section which are connected in sequence, wherein the U-shaped pipe section connected to the inlet section is a slug filling area; the U-shaped pipe horizontal pipeline is detachable; the slug horizontal movement section is detachable; a pressure transmitter and at least two conductivity probes are arranged on the slug horizontal movement section; the conductivity probe is used to realize the monitoring of the conductivity of each measuring point in the pipeline, and the time difference generated by the conductivity change between the conductivity probes and the interval between the conductivity probes are used to calculate the average movement speed of the slug in the pipeline; the pipeline of the experimental section comprises an end elbow connected to the slug horizontal movement section, a strain gauge is arranged at the end elbow, and the strain gauge is used to collect impact pressure data; a pressure transmitter is also arranged at the elbow to measure the impact pressure of the slug on the elbow.

Description

Technical Field

[0001] The invention relates to the technical field of fluid mechanics devices, and in particular to a pipeline slug motion and impact experimental system. Background Art

[0002] Under the action of high-pressure steam, the water masses formed by steam condensation can cause strong impacts on discontinuous parts of the system, causing damage. Since the problem was raised, there have been relatively abundant physical models and experimental studies. However, no universal mathematical model exists for the movement of water masses in the pipe or the impact on discontinuous parts of the pipe. Although the experimental data obtained have been integrated into the design process of the pipeline system, the current software and models are still unable to fully simulate the complex gas-liquid mixed flow and high-speed impact problem. Summary of the invention

[0003] The purpose of the present invention is to provide a pipeline slug motion and impact test system with high experimental results accuracy, more in line with actual conditions, and capable of realizing various experimental conditions. The technical solution of the present invention is as follows:

[0004] A pipeline slug movement and impact test system, characterized in that it comprises an inlet section, a U-shaped pipe section, a slug horizontal movement section and a test section which are connected in sequence, wherein:

[0005] The inlet section connected to the high-pressure steam source is provided with a quick-start ball valve 1, a first pressure transmitter 5 and a water inlet valve 2; the quick-start ball valve 1 is used to control the introduction of high-pressure steam; the first pressure transmitter 5 is connected to the pipeline through the first liquid guide tank 10, and the first pressure transmitter 5 is used to monitor the pressure of the high-pressure steam;

[0006] The U-shaped pipe section connected to the inlet section is a slug filling area, including two U-shaped pipe vertical sections and a U-shaped pipe horizontal pipeline connected between the two U-shaped pipe vertical sections, and is provided with a second pressure transmitter 6 and a drain valve; the second pressure transmitter 6 is connected to the pipeline through a second liquid guide tank 11, and the second pressure transmitter 6 is used to monitor the slug pressure; the U-shaped pipe horizontal pipeline is detachable, and is composed of a plurality of pipe units, and the pipe units are increased or decreased according to the test requirements;

[0007] The horizontal movement section of the slug is detachable and consists of a number of pipeline units. The number of pipeline units is increased or decreased according to the test requirements. A third pressure transmitter, a fourth pressure transmitter and at least two conductivity probes are arranged on the horizontal movement section of the slug. The third pressure transmitter and the fourth pressure transmitter are connected to the pipeline through corresponding liquid conduction tanks respectively. The conductivity probe is used to monitor the conductivity of each measuring point in the pipeline. The time difference generated by the conductivity change between the conductivity probes and the interval between the conductivity probes are used to calculate the average movement speed of the slug in the pipeline.

[0008] Experimental section: The pipeline of the experimental section includes an end elbow connected to the horizontal movement section of the slug, and a strain gauge 15 is arranged at the end elbow, and the strain gauge 15 is used to collect impact pressure data; a fifth pressure transmitter 9 is also arranged at the elbow, and the fifth pressure transmitter 6 is connected to the end elbow through the fifth liquid guide tank 14, which is used to measure the impact pressure of the slug on the elbow.

[0009] Furthermore, the pipeline slug movement and impact test system further comprises a liquid level measuring device 20 for measuring the liquid level of the vertical section of the U-shaped pipe. The length of the horizontal movement section of the slug is less than 5 times the initial length of the slug.

[0010] The beneficial effects of the present invention are as follows: a high-pressure steam driving device is arranged upstream, and a high-pressure steam driven slug experiment can be carried out; the slug filling section is a detachable U-shaped tube, and a disassembly experiment can be carried out according to different working conditions; pressure transmitters and conductivity probes are arranged along the process, and the movement state of the slug in the pipeline can be accurately restored, and the pressure difference and pressure drop at various locations in the pipeline can be accurately measured; the experimental section is equipped with a pressure transmitter and an impact pressure measuring device to simultaneously collect two kinds of data, which can improve the experimental accuracy and at the same time achieve mutual verification of the two data, thereby improving the credibility of the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the present invention.

[0012] The reference numerals are as follows: ball valve 1; water inlet valve 2; drain valve 3; drain valve 4; first pressure transmitter 5; second pressure transmitter 6; third pressure transmitter 7; fourth pressure transmitter 8; fifth pressure transmitter 9; first liquid guide tank 10; second liquid guide tank 11; third liquid guide tank 12; fourth liquid guide tank 13; fifth liquid guide tank 14; strain gauge 15; conductivity probe 16; conductivity probe 17; pipe support 18; pipe support 19; liquid level measuring device 20; pipe support 21; signal amplifier 22; signal collector 23 DETAILED DESCRIPTION

[0013] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0014] like Figure 1 The pipe is made of stainless steel. The length of the pipe in the figure is not in proportion. The number of measuring devices and connecting devices and the length of the pipe are determined according to different working conditions. The figure is only for reference.

[0015] The area of ​​box ① is the inlet section. The pipe sections are connected by several flanges. The left end is connected to the high-pressure steam source. The high-pressure steam is controlled by the quick-start ball valve 1. The quick-start ball valve can be operated manually or electrically to achieve precise adjustment of the opening rate and valve opening. A first pressure transmitter 5 is arranged behind the quick-start ball valve. The first pressure transmitter 5 is connected to the first liquid guide tank 10. The water in the liquid guide tank can transmit the steam pressure and isolate the temperature of the steam, avoiding direct contact between the steam and the pressure transmitter, which plays a protective role for the pressure transmitter. The pressure transmitter monitors the pressure of the high-pressure steam in real time. The water inlet valve 2 can control the volume of the initial liquid in the pipeline. The inlet section is connected to the vertical section of the U-shaped pipe through a flange. The inlet section is fixed by a pipe bracket (not shown in the figure).

[0016] Box ② is a U-shaped pipe section, which is the initial slug filling area. Before the experiment begins, a known volume of liquid is filled into the pipe from the inlet valve 2 of the inlet section to form an initial static slug in the U-shaped pipe. A second pressure transmitter 6 is arranged in the filling area. The second pressure transmitter 6 is connected to the second liquid guide tank 11. The function of the liquid guide tank is the same as above. The second pressure transmitter 6 can be used to monitor the initial pressure of the slug and the pressure during the movement. The horizontal pipe in the filling area is designed to be detachable and consists of pipe units of unit length. The pipe units are connected by flanges. The unit length is 1m and can be increased or decreased according to the test requirements. Before the experiment, the length of the initial slug in the U-shaped pipe can be adjusted by drain valves 3 and 4. Before and after the experiment, the liquid in the device can also be emptied by drain valves 3 and 4. The vertical section of the U-shaped pipe on the right is connected to the horizontal moving section of the slug through a flange. The horizontal pipe of the U-shaped pipe is fixed by pipe brackets 18 and 19.

[0017] The area in box ③ is the horizontal movement section of the slug. The length of the pipeline can be increased or decreased as needed. The pipeline units are connected by flanges, but they are required to be less than 5 times the initial length of the slug to avoid the slug being broken before reaching the terminal elbow. Several pressure transmitters (such as the third pressure transmitter 7 and the fourth pressure transmitter 8 in the figure) and conductivity probes (such as the conductivity probe 16 and the conductivity probe 17 in the figure) are arranged on the horizontal movement section. Each pressure transmitter is connected to a liquid guide tank (such as the third liquid guide tank 12 and the fourth liquid guide tank 13 in the figure). The function of the liquid guide tank is the same as above. There is a certain interval between the conductivity probes, which respectively realizes the real-time monitoring and transmission of the conductivity of each measuring point in the pipeline. When the slug front reaches the conductivity probe, the conductivity probe can monitor the change of conductivity. According to the time difference between the changes of the two conductivity probes and the interval between the conductivity probes, the average movement speed of the slug in the pipeline can be calculated. A liquid level measuring device 20 is arranged near the U-shaped pipe, and the bottom of the device is connected to the horizontal section of the U-shaped pipe through a pipeline, which can measure the liquid level of the vertical section of the U-shaped pipe and control the length of the initial segment plug. The horizontal moving section is fixed by a pipeline bracket 21.

[0018] Box ④ is the test section, and the strain gauge 15 is fixed at the elbow of the test section. The strain gauge 15 can collect the strain generated by the elbow of the test section due to the impact pressure, and amplify the electrical signal generated by the strain gauge through the signal amplifier 22, and finally transmit it to the signal collector 23 to be converted into impact pressure data.

[0019] At the beginning of the experiment, after a certain length of clean water is filled in the slug filling area, the quick-opening ball valve 1 is opened, and the high-pressure steam drives the static slug to move at high speed in the empty pipe until it hits the end elbow and flows into the water collection tank. The sensors along the pipeline transmit the measured data to the computer for analysis and calculation, and the change rules of characteristic parameters such as slug movement speed, slug length, slug gas content, pressure at each point, pressure drop along the way, and impact pressure are obtained.

[0020] (1) First determine the length of the pipeline, including the length of the slug filling section and the horizontal movement section. After connecting the pipeline and the experimental instrument, check that the pipeline bracket is firmly fixed and the pipeline has completed the pressure test and leakage test in accordance with relevant requirements. Check whether the instrument, sensor, etc. are working properly.

[0021] (2) Fill the corresponding volume of water into the pipe through the water inlet valve 2 and let it stand for two minutes to eliminate bubbles.

[0022] (3) Confirm the pressure at the high-pressure steam end, adjust the opening of the quick-opening ball valve 1 to 100%, close the quick-opening ball valve 1 after the steam drives the static segment plug to complete the impact process, and open the drain valve 3 and drain valve 4 to discharge the residual liquid in the pipeline. To ensure the repeatability of the experiment, each working condition is operated multiple times. The experimental data of each measuring point are processed to obtain relevant characteristic parameters.

[0023] (4) Repeat step (2), change the opening of the quick-start ball valve 1, and repeat the experimental process of step (3).

[0024] (5) After completion, conduct the next set of experiments and repeat the above steps.

[0025] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A pipeline slug motion and impact test system, characterized in that: It includes an inlet section, a U-shaped pipe section, a slug horizontal movement section and a test section which are connected in sequence, wherein: The inlet section connected to the high-pressure steam source is provided with a quick-start ball valve (1), a first pressure transmitter (5) and a water inlet valve (2); the quick-start ball valve (1) is used to control the introduction of high-pressure steam; the first pressure transmitter (5) is connected to the pipeline through the first liquid guide tank (10), and the first pressure transmitter (5) is used to monitor the pressure of the high-pressure steam; The U-shaped pipe section connected to the inlet section is a slug filling area, including two U-shaped pipe vertical sections and a U-shaped pipe horizontal pipeline connected between the two U-shaped pipe vertical sections, and is provided with a second pressure transmitter (6) and a drain valve; the second pressure transmitter (6) is connected to the pipeline through a second liquid guide tank (11), and the second pressure transmitter (6) is used to monitor the slug pressure; the U-shaped pipe horizontal pipeline is detachable and consists of a plurality of pipe units, and the pipe units are increased or decreased according to test requirements; The horizontal movement section of the slug is detachable and consists of a number of pipeline units. The number of pipeline units is increased or decreased according to the test requirements. A third pressure transmitter, a fourth pressure transmitter and at least two conductivity probes are arranged on the horizontal movement section of the slug. The third pressure transmitter and the fourth pressure transmitter are connected to the pipeline through corresponding liquid conduction tanks respectively. The conductivity probe is used to monitor the conductivity of each measuring point in the pipeline. The time difference generated by the conductivity change between the conductivity probes and the interval between the conductivity probes are used to calculate the average movement speed of the slug in the pipeline. The experimental section, the pipeline of the experimental section includes an end elbow connected to the horizontal movement section of the slug, a strain gauge (15) is arranged at the end elbow, and the strain gauge (15) is used to collect impact pressure data; a fifth pressure transmitter (9) is also arranged at the elbow, and the fifth pressure transmitter (9) is connected to the end elbow through a fifth liquid guide tank (14) and is used to measure the impact pressure of the slug on the elbow.

2. The pipeline slug movement and impact test system according to claim 1, characterized in that: The pipeline segment movement and impact experimental system also includes a liquid level measuring device (20) for measuring the liquid level of the vertical section of the U-shaped pipe.

3. The pipeline slug movement and impact test system according to claim 1, characterized in that: The length of the horizontal moving section of the slug is less than 5 times the initial length of the slug.

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