CN114894436A

CN114894436A - Pipeline slug motion and impact experiment system

Info

Publication number: CN114894436A
Application number: CN202210560377.7A
Authority: CN
Inventors: 侯庆志; 范怀诚; 林磊; 苏志伟; 谭超
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2022-05-23
Filing date: 2022-05-23
Publication date: 2022-08-12

Abstract

The invention relates to a pipeline slug movement and impact experiment system which is characterized by comprising an inlet section, a U-shaped pipe section, a slug horizontal movement section and an experiment section which are sequentially communicated, wherein the U-shaped pipe section communicated with 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 conductance probes are arranged on the slug horizontal movement section; the conductance probes are used for monitoring the conductivity of each measuring point in the pipeline, calculating the average movement speed of the section plug in the pipeline according to the time difference generated by the conductivity change among the conductance probes and the interval among the conductance probes; the pipeline of the experimental section comprises a tail end elbow communicated with the slug horizontal movement section, and a strain gauge is arranged at the tail end elbow and used for collecting impact pressure data; and the elbow is also provided with a pressure transmitter for measuring the impact pressure of the slug on the elbow.

Description

Pipeline slug motion and impact experiment system

Technical Field

The invention relates to the technical field of fluid mechanics devices, in particular to a pipeline slug movement and impact experiment system.

Background

Under the action of high-pressure steam, water mass formed by steam condensation can cause strong impact on discontinuous parts in the system, so that the discontinuous parts are damaged. Since this problem has been addressed, physical models and experimental studies have been relatively abundant, however, no universally applicable mathematical model exists, whether for the movement of water masses within pipes or the impact of non-continuous portions of pipes. Although the obtained experimental data are integrated in the design process of the pipeline system, the current software and model still cannot fully simulate the complicated gas-liquid mixed flow and high-speed impact problem.

Disclosure of Invention

The invention aims to provide a pipeline slug movement and impact experiment system which is high in accuracy of experiment results, more suitable for actual conditions and capable of realizing various experiment conditions. The technical scheme of the invention is as follows:

a pipeline slug motion and impact experiment system is characterized by comprising an inlet section, a U-shaped pipe section, a slug horizontal motion section and an experiment section which are sequentially communicated, wherein,

the inlet section connected with the high-pressure steam source is provided with a quick-opening ball valve 1, a first pressure transmitter 5 and a water inlet valve 2; the quick-start ball valve 1 is used for controlling the introduction of high-pressure steam; the first pressure transmitter 5 is connected to the pipeline through a first liquid guiding tank 10, and the first pressure transmitter 5 is used for monitoring the pressure of the high-pressure steam;

the U-shaped pipe section communicated with the inlet section is a slug filling area and comprises a U-shaped pipe horizontal pipeline connected between two U-shaped pipe vertical sections through the two U-shaped pipe vertical sections, and a second pressure transmitter 6 and a water drain valve are arranged; the second pressure transmitter 6 is connected to the pipeline through a second liquid guiding tank 11, and the second pressure transmitter 6 is used for monitoring the slug pressure; the U-shaped pipe horizontal pipeline is detachable and consists of a plurality of pipeline units, and the pipeline units are increased or decreased according to the test requirements;

the slug horizontal movement section is detachable and consists of a plurality of pipeline units, and the pipeline units are increased or decreased according to the test requirements; a third pressure transmitter, a fourth pressure transmitter and at least two conductance probes are arranged on the slug horizontal movement section, and the third pressure transmitter and the fourth pressure transmitter are respectively connected to the pipeline through corresponding liquid guiding tanks; the conductance probes are used for monitoring the conductivity of each measuring point in the pipeline, calculating the average movement speed of the section plug in the pipeline according to the time difference generated by the conductivity change among the conductance probes and the interval among the conductance probes;

the pipeline of the experimental section comprises a tail end elbow communicated with the slug horizontal movement section, a strain gauge 15 is arranged at the tail end elbow, and the strain gauge 15 is used for collecting impact pressure data; a fifth pressure transmitter 9 is also arranged at the elbow, and a fifth pressure transmitter 6 is connected to the tail end elbow through a fifth liquid guiding tank 14 and is used for measuring the impact pressure of the slug on the elbow.

Further, the pipe slug motion and impact experiment 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 slug moving section is less than 5 times the initial length of the slug.

The invention has the beneficial effects that: the upper reaches are provided with high-pressure steam drive arrangement, can carry out the experiment of high-pressure steam drive slug, the slug filling section is for dismantling U type pipe, can dismantle the experiment according to different operating modes, along the journey be provided with pressure transmitter and conductance probe, can accurate reduction slug motion state in the pipeline, pressure difference and pressure drop everywhere in the accurate measurement pipeline, the experiment section is gathered two kinds of data simultaneously by pressure transmitter and impulse pressure measuring device, can also accomplish two data and verify each other when improving the experiment precision, improve the credibility of experiment.

Drawings

FIG. 1 is a schematic view of the structure of the present invention.

The reference numerals are explained below: starting a ball valve 1; a water inlet valve 2; a water drain valve 3; a water drain valve 4; a first pressure transmitter 5; a second pressure transmitter 6; a third pressure transmitter 7; a fourth pressure transmitter 8; a fifth pressure transmitter 9; a first liquid guiding tank 10; a second liquid guiding tank 11; a third liquid guiding tank 12; a fourth liquid guiding tank 13; a fifth liquid lead tank 14; a strain gauge 15; a conductance probe 16; a conductance probe 17; a pipe bracket 18; a pipe support 19; a liquid level measuring device 20; a pipe support 21; a signal amplifier 22; signal collector 23

Detailed Description

The foregoing and other objects, features, and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.

As shown in fig. 1. The pipeline is made of stainless steel, the length of the pipeline is not to scale in the drawing, the number of the measuring devices and the connecting devices and the length of the pipeline are determined according to different working conditions, and the pipeline is only referred to as a device in the drawing.

The area of the square frame is an inlet section, the pipe sections are connected through a plurality of flanges, the left end of the square frame is connected with a high-pressure steam source, the introduction of high-pressure steam is controlled through a quick-opening ball valve 1, the quick-opening ball valve can be operated manually or electrically to realize accurate adjustment of opening speed and valve opening, a first pressure transmitter 5 is arranged behind the quick-opening ball valve, the first pressure transmitter 5 is connected with a first liquid guiding tank 10, water in the liquid guiding tank can transmit steam pressure and isolate the temperature of the steam, the steam is prevented from being in direct contact with the pressure transmitter, the pressure transmitter is protected, the pressure transmitter monitors the pressure of the high-pressure steam in real time, a water inlet valve 2 can control the volume of initial liquid in the pipe, and the inlet section is connected with the vertical section of the U-shaped pipe through the flanges. The inlet section is secured by a pipe bracket (not shown).

And a square frame II is a U-shaped pipeline section which is an initial slug filling area, liquid with a known volume is filled into the pipeline from the inlet section water inlet valve 2 before the experiment begins, and an initial static slug is formed in the U-shaped pipeline. Second pressure transmitter 6 is arranged in the filling area, second pressure transmitter 6 is connected with second liquid guiding tank 11, the liquid guiding tank is used as above, second pressure transmitter 6 can be used for monitoring the initial pressure of the slug and the pressure in the motion process, a horizontal pipeline in the filling area is designed to be detachable and consists of pipeline units with unit length, flange connection is adopted between the pipeline units, the unit length is 1m, and the visual test requirements are increased or reduced. Can adjust the length of initial slug in the U type pipe through valve 3, 4 drain valves before the experiment, also can be through drain valve 3, 4 drain valve emptiers in the device before the experiment, the U type pipe vertical section on right side passes through the flange and is connected with slug horizontal motion section. The U-shaped pipe horizontal pipeline is fixed through a pipeline bracket 18 and a pipeline bracket 19.

The area III is a slug horizontal movement section, the length of the pipeline can be increased or decreased according to the situation, the pipeline units are connected through flanges, but the initial length of the slug is required to be less than 5 times, so that the slug is prevented from being broken when the slug does not reach the tail end elbow. The horizontal motion segment is provided with a plurality of pressure transmitters (such as a third pressure transmitter 7 and a fourth pressure transmitter 8 in the figure) and conductance probes (such as a conductance probe 16 in the figure and a conductance probe 17 in the figure), each pressure transmitter is connected with a liquid guiding tank (such as a third liquid guiding tank 12 and a fourth liquid guiding tank 13 in the figure), the liquid guiding tanks have the same function, and certain intervals are formed among the conductance probes to respectively realize real-time monitoring and transmission of the conductivity of each measuring point in the pipeline. A liquid level measuring device 20 is arranged at a position close to the U-shaped pipe, the bottom of the device is connected with the horizontal section of the U-shaped pipe through a pipeline, the liquid level of the vertical section of the U-shaped pipe can be measured, and the length of an initial slug is controlled. The horizontal movement section is fixed by a pipe bracket 21.

The frame IV is an experimental section, the strain gauge 15 is fixed at the elbow of the experimental section, the strain gauge 15 can collect the strain of the elbow of the experimental section caused by the impact pressure, the signal amplifier 22 amplifies the electric signal generated by the strain gauge and finally transmits the electric signal to the signal collector 23 to be converted into the impact pressure data.

When the experimental process begins, after clean water with a certain length is filled in a section plug filling area, the quick-opening ball valve 1 is opened, and the high-pressure steam drives the static section plug to move at a high speed in the hollow pipe until the static section plug collides with the tail end elbow and then flows into the water collecting tank. The sensors along the pipeline transmit the measured data to a computer for analysis and calculation to obtain the change rules of the characteristic parameters such as the motion speed of the slug, the length of the slug, the gas content of the slug, the pressure of each point, the pressure drop along the way, the impact pressure and the like.

(1) The length of the pipeline, including the length of the slug filling section and the length of the horizontal motion section, is first determined. After the pipeline and the experimental instrument are connected, the pipeline bracket is checked to be fixed firmly, and the pipeline completes a pressure test and a leakage test according to relevant requirements. And checking whether the instruments, the sensors and the like work normally or not.

(2) Corresponding volume of water is filled into the pipeline through the water inlet valve 2, and the pipeline is kept still for two minutes to eliminate bubbles.

(3) And (3) confirming the pressure of the high-pressure steam end, adjusting the opening of the quick-opening ball valve 1 to 100%, closing the quick-opening ball valve 1 after the steam drives the static slug to finish the impact process, and opening the drain valve 3 and the drain valve 4 to discharge residual liquid in the pipeline. To ensure the repeatability of the experiment, each operating condition was operated multiple times. And processing the experimental data of each measuring point to obtain related characteristic parameters.

(4) And (5) repeating the step (2), changing the opening of the quick-start ball valve 1, and repeating the experiment process of the step (3).

(5) And after the test is finished, carrying out the test of the next set of working conditions, and repeating the operation.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiment according to the present invention are within the scope of the present invention.

Claims

1. A pipeline slug motion and impact experiment system is characterized by comprising an inlet section, a U-shaped pipe section, a slug horizontal motion section and an experiment section which are sequentially communicated, wherein,

the inlet section connected with the high-pressure steam source is provided with a quick-opening ball valve (1), a first pressure transmitter (5) and a water inlet valve (2); the quick-start ball valve (1) is used for controlling the introduction of high-pressure steam; the first pressure transmitter (5) is connected to the pipeline through a first liquid guiding tank (10), and the first pressure transmitter (5) is used for monitoring the pressure of the high-pressure steam;

the U-shaped pipe section communicated with the inlet section is a slug filling area and comprises a U-shaped pipe horizontal pipeline connected between two U-shaped pipe vertical sections through the two U-shaped pipe vertical sections, and a second pressure transmitter (6) and a water drain valve are arranged; the second pressure transmitter (6) is connected to the pipeline through a second liquid guiding tank (11), and the second pressure transmitter (6) is used for monitoring the slug pressure; the U-shaped pipe horizontal pipeline is detachable and consists of a plurality of pipeline units, and the pipeline units are increased or decreased according to the test requirements;

the pipeline of the experimental section comprises a tail end elbow communicated with the slug horizontal movement section, a strain gauge (15) is arranged at the tail end elbow, and the strain gauge (15) is used for collecting impact pressure data; and a fifth pressure transmitter (9) is also arranged at the elbow, and the fifth pressure transmitter (6) is connected to the tail end elbow through a fifth liquid guiding tank (14) and is used for measuring the impact pressure of the slug on the elbow.

2. The pipe slug motion and impact testing system according to claim 1, further comprising a liquid level measuring device (20) for measuring the liquid level of the vertical section of the U-shaped pipe.

3. The pipe slug motion and impact experimentation system according to claim 1, wherein the length of the slug horizontal motion section is less than 5 times the initial slug length.