Pipeline flow flash evaporation characteristic research device and method

Abstract

The invention discloses a pipeline flow flash evaporation characteristic research device and method, and relates to the technical field of fluid mechanics, and the device comprises a gas supply device which is connected with an experiment pipeline system and is used for enabling an experiment pipeline to be filled with high-pressure liquefied gas; the experimental pipeline system is used for heating an experimental pipeline and releasing the pressure when the current pressure is equal to the pressure required by the experiment; the data acquisition device is connected with the experimental pipeline system and is used for observing the temperature of an experimental pipeline to reach the experimental temperature and observing whether the current pressure reaches the pressure required by an experiment or not; and after the pressure is released, observing the pressure data, and after the pressure data is not reduced any more, stopping recording the data so as to complete the pressure release experiment. The flow flash evaporation phenomenon caused by pressure relief of the high-pressure liquefaction pipeline is simulated, the leakage disaster-causing process of the high-pressure liquefaction pipeline can be known easily, and the safe operation level of the pipeline is improved.

Description

Technical Field

[0001] This application relates to the technical field of fluid mechanics, and particularly to a device and method for studying the flashing characteristics of pipeline flow. Background Art

[0002] As a common chemical equipment, pressure pipelines are usually used to transport raw materials and products between chemical equipment, or to transport the media of thermodynamic cycle systems and refrigeration systems, and as long-distance transportation pipelines. Pressure pipelines are often used to transport high-pressure liquefied gases, such as liquefied petroleum gas, liquefied ethane, liquefied ethylene, liquefied carbon dioxide, etc. These chemicals not only have the risks of combustion, explosion and toxicity, but also have boiling points far lower than normal temperature, so they are gases under normal temperature and pressure.

[0003] The boiling point of a substance is positively correlated with the pressure it is under. When the pressure increases to a certain extent, its boiling point rises and exceeds the temperature of its surrounding environment, and the substance will change from a gas to a liquid. This is the principle of high-pressure liquefaction. However, when the pressure of a high-pressure liquefaction pipeline suddenly drops (such as in a leakage accident), the boiling point of the liquid in the pipeline will quickly drop below the liquid temperature, and the liquid enters a superheated state. The superheated state is a very unstable state, and superheated liquids usually undergo violent phase changes such as boiling and flashing, resulting in serious consequences such as shock wave overpressure, low temperature, brittle and ductile fracture of the pipeline, and high-concentration accumulation of dangerous substances. This not only damages the pipeline system itself, but also has a negative impact on the surrounding environment and personnel. Therefore, it is urgently necessary to improve the understanding and solution ability of the phase change control problem caused by the sudden reduction of pipeline pressure when high-pressure liquefied gas leaks during pipeline transmission.

[0004] The above content is only used to assist in understanding the technical solution of this application, and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of this application is to provide a device and method for studying the flashing characteristics of pipeline flow, aiming to solve the technical problem of how to improve the understanding and solution ability of the flow flashing phenomenon caused by the sudden reduction of pipeline pressure when high-pressure liquefied gas leaks during pipeline transmission.

[0006] To achieve the above purpose, this application proposes a device for studying the flashing characteristics of pipeline flow, and the device includes: A gas supply device, which is connected to the experimental pipeline system and is used to fill the experimental pipeline with high-pressure liquefied gas; An experimental pipeline system, which is used to heat the experimental pipeline and release pressure when the current experimental pipeline pressure is equal to the required experimental pressure; A data acquisition device, which is connected to the experimental pipeline system, is used to observe the temperature of the experimental pipeline to reach the experimental temperature and to observe whether the current pressure of the experimental pipeline reaches the pressure required for the experiment; after pressure relief, observe the pressure data, and stop recording the data after the pressure data no longer decreases to complete the pressure relief experiment.

[0007] In one embodiment, the gas supply device includes a high-pressure liquefied gas insertion cylinder, a high-pressure liquefied gas general cylinder, a liquid booster pump, a gas guide pipe, a first pneumatic ball valve and a second pneumatic ball valve. The liquid booster pump is installed at the connection between the high-pressure liquefied gas insertion cylinder and the first pneumatic ball valve. The other end of the first pneumatic ball valve is connected to the gas guide pipe. The high-pressure liquefied gas general cylinder is connected to the gas guide pipe through the second pneumatic ball valve. The gas supply device is connected to the experimental pipeline of the experimental pipeline system through the gas guide pipe, and the first pneumatic ball valve of the high-pressure liquefied gas insertion cylinder is used to fill the experimental pipeline with high-pressure liquefied gas.

[0008] In one embodiment, the experimental pipeline system includes: an experimental pipeline, which is composed of several groups of short pipes connected by joints; a movable window, a movable relief port and a needle valve are provided on the experimental pipeline. The joints and the movable window are provided with several through holes for installing sensors; a heating tape, a heat insulating material and a refrigeration device are also provided on the outer surface of the experimental pipeline, and the experimental pipeline is heated by the heating tape.

[0009] In one embodiment, the heating tape is wound around the outer surface of the experimental pipeline to increase the temperature of the high-pressure liquefied gas; the refrigeration device includes a refrigerator and a silica gel hose. The coolant of the refrigerant flows into the silica gel hose, and the silica gel hose is wound around the outer surface of the experimental pipeline to reduce the temperature of the high-pressure liquefied gas through the coolant inside the silica gel hose; the heat insulating material wraps the heating tape or the refrigeration device and is wound around the outer surface of the experimental pipeline to perform heat insulation treatment on the experimental pipeline and adjust the temperature of the high-pressure liquefied gas in the experimental pipeline to reach the experimental expected temperature.

[0010] In one embodiment, the data acquisition device includes a temperature sensor, a pressure sensor, a data acquisition instrument, a high-speed camera and a control computer; the temperature sensor and the pressure sensor are both installed at several through holes of the joints and the movable window. The data acquisition instrument collects the data of the temperature sensor and the pressure sensor and is connected to the control computer through a special data cable, which is used to observe the temperature of the experimental pipeline to reach the experimental temperature and to observe whether the current pressure of the experimental pipeline reaches the pressure required for the experiment.

[0011] In one embodiment, the needle valve is fixedly connected directly above the nearest set of short pipes at the connection between the experimental pipeline and the gas supply device. The needle valve is used to control the flow rate of the high-pressure liquefied gas to adjust the pressure of the experimental pipeline to the pressure required for the experiment.

[0012] In one embodiment, the movable relief port is movably connected to any short pipe of the experimental pipeline. A groove is provided at the middle position of the movable relief port. The bottom of the groove is used to install orifice plates with different apertures and shapes. The orifice plate is provided with relief holes. The groove is installed with a third pneumatic ball valve through threaded connection. The movable relief port controls the pressure relief of the high-pressure liquefied gas at the pressure required for the experiment through the third pneumatic ball valve.

[0013] In one embodiment, the movable viewing window is movably connected to any short pipe of the experimental pipeline. The movable viewing window includes a flange, a high-transparency organic glass, and a main structure. The center of the flange is provided with an opening, and the high-transparency organic glass is fixedly connected to the main structure through bolts; the high-speed camera is installed directly in front of the movable viewing window to observe the high-pressure liquefied gas in the experimental pipeline, and the pressure data of the high-pressure liquefied gas is observed through the data acquisition instrument. After the pressure data no longer decreases, stop recording the data to complete the pressure relief experiment.

[0014] In one embodiment, the data acquisition device further includes a power distribution cabinet. The power distribution cabinet is respectively connected to the data acquisition instrument and the control computer. The power distribution cabinet is also connected to the heating tape and the refrigeration equipment of the experimental pipeline system for supplying power to the connection devices of the data acquisition device and the experimental pipeline system.

[0015] In addition, to achieve the above object, the present application also proposes a research method for the flow flashing characteristics of pipelines. The method includes: Open the first pneumatic ball valve of the high-pressure liquefied gas insertion cylinder of the gas supply device to fill the experimental pipeline with high-pressure liquefied gas; Heat the experimental pipeline through the heating tape, and observe the temperature through the data acquisition instrument of the data acquisition device to reach the experimental temperature; Observe through the data acquisition instrument whether the current pressure of the experimental pipeline reaches the pressure required for the experiment; When the current pressure of the experimental pipeline is equal to the pressure required for the experiment, open the pneumatic ball valve on the movable pressure relief valve of the experimental pipeline system to conduct pressure relief; Observe the pressure data through the data acquisition device. After the pressure data no longer decreases, stop recording the data to complete the pressure relief experiment.

[0016] In addition, to achieve the above object, the present application also provides a research device for the flash evaporation characteristics of pipeline flow, the device comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, the computer program being configured to implement the steps of the research method for the flash evaporation characteristics of pipeline flow as described above.

[0017] In addition, to achieve the above object, the present application also provides a storage medium, the storage medium being a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the research method for the flash evaporation characteristics of pipeline flow as described above are implemented.

[0018] In addition, to achieve the above object, the present application also provides a computer program product, the computer program product comprising a computer program, and when the computer program is executed by a processor, the steps of the research method for the flash evaporation characteristics of pipeline flow as described above are implemented.

[0019] The technical solution of the present invention simulates the process of flash evaporation caused by a sudden decrease in pipeline pressure due to pressure leakage in a high-pressure liquefied pipeline by setting a gas supply device, an experimental pipeline system, and a data acquisition device. During the simulation of the experimental pipeline, the experimental pipeline system is supplied with gas by the gas supply device. The experimental pipeline system accommodates the high-pressure liquefied gas provided by the gas supply device. The high-pressure liquefied gas is heated to the expected experimental temperature by the heating tape of the experimental pipeline system. Whether the current pressure of the experimental pipeline reaches the required experimental pressure is observed by a data acquisition instrument. When the current pressure of the experimental pipeline is equal to the required experimental pressure, a sudden pressure drop caused by a small hole leakage on the pipeline wall is simulated through a movable relief port provided on the experimental pipeline system, and the flash evaporation phenomenon is observed through a movable window. The data acquisition device is used to observe the temperature and pressure of the high-pressure liquefied gas in the experimental pipeline system and record the experimental data when the pressure of the high-pressure liquefied gas leaks. In this way, the research device for the flash evaporation characteristics of pipeline flow of the technical solution of the present application can simulate the phenomenon of flash evaporation caused by a sudden pressure drop due to pressure leakage of high-pressure liquefied gas in a high-pressure liquefied pipeline. At the same time, dynamically adjusting the positions of the sensors, the windows, and the relief ports is beneficial to further understanding the disaster-causing process of high-pressure liquefied pipeline leakage, collecting more detailed data, optimizing pipeline design, improving safety measures, and enhancing the safe operation level of the pipeline. For the flash evaporation phenomenon caused by pipeline leakage during the transmission of existing high-pressure liquefied gas pipelines, it is beneficial to further understand the disaster-causing process of high-pressure liquefied pipeline leakage. Through the accumulation and analysis of experimental data, it can provide guidance for pipeline operation and maintenance, reduce potential safety risks, and enhance the safe operation level of the pipeline. Description of the Drawings

[0020] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application and, together with the specification, are used to explain the principles of this application.

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a schematic structural diagram of an embodiment of the research device for the flash evaporation characteristics of pipeline flow in this application; Figure 2a It is a schematic structural diagram of a short pipe and a joint in an embodiment of the research device for the flash evaporation characteristics of pipeline flow in this application; Figure 2b and Figure 2c It is a partial enlarged view of the schematic structural diagram of a joint in an embodiment of the research device for the flash evaporation characteristics of pipeline flow in this application; Figure 3 It is a first schematic structural diagram of a movable relief port in an embodiment of the research device for the flash evaporation characteristics of pipeline flow in this application; Figure 4 It is a second schematic structural diagram of a movable relief port in an embodiment of the research device for the flash evaporation characteristics of pipeline flow in this application; Figure 5 It is a first schematic structural diagram of a movable viewing window in an embodiment of the research device for the flash evaporation characteristics of pipeline flow in this application; Figure 6 It is a second schematic structural diagram of a movable viewing window in an embodiment of the research device for the flash evaporation characteristics of pipeline flow in this application; Figure 7 It is a third schematic structural diagram of a movable viewing window in an embodiment of the research device for the flash evaporation characteristics of pipeline flow in this application.

[0023] Explanation of the reference numerals in the accompanying drawings: 100, gas supply device; 1, high-pressure liquefied gas insertion steel cylinder; 2, high-pressure liquefied gas ordinary steel cylinder; 3, liquid booster pump; 4, gas guide pipe; 5, first pneumatic ball valve; 6, second pneumatic ball valve; 11, third pneumatic ball valve; 200, experimental pipeline system; 7, needle valve; 8, short pipe and joint; 81, short pipe; 8100, thread; 8110, threaded sleeve; 8120, gasket; 82, joint; 8200, sensor jack; 8300, groove; 8400, orifice plate; 9, movable viewing window; 10, movable relief port; 300. Data acquisition device; 15. Power distribution cabinet; 16. Control computer; 17. T temperature sensor; 18. P pressure sensor; 19. Data acquisition instrument; 20. High-speed camera.

[0024] The realization of the purpose, functional features and advantages of this application will be further described in conjunction with the embodiments with reference to the accompanying drawings. Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0027] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0028] This application proposes a device for studying the characteristics of flashing in pipeline flow. The device for studying the characteristics of flashing in pipeline flow includes: A gas supply device, which is connected to the experimental pipeline system and is used to fill the experimental pipeline with high-pressure liquefied gas; An experimental pipeline system, which is used to heat the experimental pipeline and release pressure when the current pressure of the experimental pipeline is equal to the required pressure for the experiment; A data acquisition device, which is connected to the experimental pipeline system and is used to observe the temperature of the experimental pipeline to reach the experimental temperature and observe whether the current pressure of the experimental pipeline reaches the required pressure for the experiment; after the pressure is released, observe the pressure data, and stop recording the data after the pressure data no longer decreases to complete the pressure release experiment.

[0029] In the simulation process of the pressure leakage of the experimental pipeline in the technical solution of this application, the experimental pipeline system is supplied with gas by a gas supply device. The experimental pipeline system accommodates the high-pressure liquefied gas provided by the gas supply device. The high-pressure liquefied gas is heated to the expected experimental temperature by the heating tape of the experimental pipeline system. Whether the current pressure of the experimental pipeline reaches the required experimental pressure is observed through a data acquisition instrument. When the current pressure of the experimental pipeline is equal to the required experimental pressure, a small hole leakage on the pipeline wall surface is simulated through a movable discharge port provided on the experimental pipeline system, resulting in a sudden drop in pressure, and the flow flashing phenomenon is observed through a movable window. The data acquisition device is used to observe the temperature and pressure of the high-pressure liquefied gas in the experimental pipeline system and record the experimental data when the pressure leakage of the high-pressure liquefied gas occurs.

[0030] It should be noted that the flow flashing refers to the process in which when the pressure of the high-pressure liquefied gas leaks, due to the sudden drop in pressure, the liquid rapidly changes into a gas state. This process may be accompanied by a sharp temperature drop and an increase in flow rate, thereby causing damage to the pipeline structure and even triggering safety accidents.

[0031] In one embodiment, as Figure 1 shown, in the simulation process of the experimental pipeline, the gas supply device 100 includes a high-pressure liquefied gas inserting cylinder 1, a high-pressure liquefied gas ordinary cylinder 2, a liquid booster pump 3, a gas guide pipe 4, a first pneumatic ball valve 5, and a second pneumatic ball valve 6. The liquid booster pump 3 is installed at the connection between the high-pressure liquefied gas inserting cylinder 1 and the first pneumatic ball valve 5. The other end of the first pneumatic ball valve 5 is connected to the gas guide pipe 4. The high-pressure liquefied gas ordinary cylinder 2 is connected to the gas guide pipe 4 through the second pneumatic ball valve 6. The gas supply device 100 is connected to the experimental pipeline of the experimental pipeline system through the gas guide pipe 4. The first pneumatic ball valve 5 for the high-pressure liquefied gas inserting cylinder 1 fills the experimental pipeline with high-pressure liquefied gas.

[0032] It should be noted that the high-pressure liquefied gas at least includes liquefied petroleum gas, liquefied ethane, liquefied ethylene, and liquefied carbon dioxide, which are gases under normal temperature and pressure, and the boiling point of a substance is positively correlated with the pressure it is under. Power on the test bench, check whether the first pneumatic ball valve 5 and the second pneumatic ball valve 6 can be opened and closed normally, confirm whether the data acquisition device can operate normally, close the first pneumatic ball valve 5 and the second pneumatic ball valve 6, and conduct an airtightness test. Specifically, for the airtightness test, open the ordinary steel cylinder 2 of high-pressure liquefied gas, open the second pneumatic ball valve 6, observe the pressure change monitored by the data acquisition instrument 19. After the pressure no longer rises, let it stand for 10 minutes, and during this period, pay attention to whether the pressure drops, so as to confirm whether there is an air leakage phenomenon in the experimental device; when the airtightness inspection result of the experimental device meets the standard, close the ordinary steel cylinder 2 of high-pressure liquefied gas, close the second pneumatic ball valve 6, open the third pneumatic ball valve 11, discharge the gas in the pipeline, observe the pressure change here, and after the pressure no longer drops, close the third pneumatic ball valve 11.

[0033] Furthermore, the experimental pipeline system 200 includes: an experimental pipeline, which is composed of several groups of short pipes 81 connected by joints 82; a movable window 9, a movable relief port 10, and a needle valve 7 are provided on the experimental pipeline; several through holes are provided on the joint 82 and the movable window 9 for installing sensors; a heating tape 12, a heat-insulating material 14, and a refrigeration device 13 are also provided on the outer surface of the experimental pipeline, and the experimental pipeline is heated by the heating tape 12.

[0034] It should be noted that as Figure 2a shown, the inner diameter specifications of the short pipe 81 and the joint 82 are the same. Short pipes 81 of various specification lengths can be provided, and different specification lengths and quantities of short pipes 81 and joints 82 are selected according to actual experimental needs to customize the length of the experimental pipeline and the spatial density of sensor arrangement, thereby enhancing the flexibility of data acquisition and the universality of research conclusions; the short pipe 81 and the joint 82 can be connected by threads 8100, where Figure 2b is Figure 2a a partial enlarged view of the joint. The thread 8100 at the connection between the short pipe 81 and the joint 82 is provided by a thread sleeve 8110. As Figure 2c shown, the internal structure of the thread sleeve 8110 can be observed, and the interface can be sealed by a gasket 8120 made of polytetrafluoroethylene. The joint 82 is provided with several sensor jacks 8200.

[0035] Furthermore, the heating tape 12 is wound around the outer surface of the experimental pipeline to raise the temperature of the high-pressure liquefied gas; the refrigeration device 13 includes a refrigerator and a silica gel hose. The coolant of the refrigerant flows into the silica gel hose, and the silica gel hose is wound around the outer surface of the experimental pipeline to lower the temperature of the high-pressure liquefied gas through the coolant inside the silica gel hose; the heat insulation material 14 wraps the heating tape 12 or the refrigeration device 13 and is wound around the outer surface of the experimental pipeline to perform heat insulation treatment on the experimental pipeline and adjust the temperature of the high-pressure liquefied gas in the experimental pipeline to the expected experimental temperature.

[0036] Specifically, the coolant of the refrigerator can use calcium chloride solution (concentration 30%, freezing point about -55°C). The coolant flows from the refrigerator into the silica gel hose, cools the experimental pipeline, and then enters the refrigerator through the silica gel hose circuit to complete a heat exchange cycle. The heat insulation material 14 can adopt nitrile rubber heat insulation cotton. For example, when performing a cooling operation, open the heat insulation material 14, remove the heating tape 12, and wind the silica gel hose of the refrigeration device around the experimental pipeline for cooling. If a heating operation is to be performed, turn on the heating tape 12 to heat the experimental pipeline. During this period, observe the data acquisition instrument 19. When the temperature rises to the required experimental temperature, turn off the heating tape 12, which helps to avoid data errors caused by the influence of the external temperature on the experimental pipeline.

[0037] Furthermore, as Figure 1 shown, the data acquisition device includes a T temperature sensor 17, a P pressure sensor 18, a data acquisition instrument 19, a high-speed camera 20, and a control computer 16; both the T temperature sensor 17 and the P pressure sensor 18 are installed at several through holes of the joint 82 and the movable window 9. The data acquisition instrument 19 collects the data of the T temperature sensor 17 and the P pressure sensor 18 and is connected to the control computer 16 through a special data cable to observe the temperature of the experimental pipeline to reach the experimental temperature and observe whether the current pressure of the experimental pipeline reaches the required experimental pressure.

[0038] It should be noted that the T temperature sensor 17 can select a PT100 thermal resistor, which is applicable to -200°C to 400°C; the P pressure sensor 18 can select an HM28 sapphire pressure transmitter from HELM in Germany, with a range of 0 to 15 MPa and an accuracy of 0.25% FS, which is applicable to -60°C to 150°C; the data acquisition instrument 19 is an Agilent Technologies 34980A and a KeysightU2300A; the control computer 16 monitors the sensor data in real time through software, obtains the current temperature and current pressure of the high-pressure liquefied gas, and adjusts the current pressure to the required experimental pressure through the first pneumatic ball valve 5.

[0039] Furthermore, the needle valve 7 is fixedly connected directly above the nearest set of short pipes 81 at the connection between the experimental pipeline and the gas supply device. The needle valve 7 is used to control the flow rate of the high-pressure liquefied gas to adjust the pressure in the experimental pipeline to the pressure required for the experiment.

[0040] It should be noted that the needle valve 7 can be used for fine-tuning the pressure of the experimental pipeline and for emergency pressure relief. During the experiment, when precise control of the pressure inside the pipeline is required, the operator can control the flow rate of the high-pressure liquefied gas by slowly rotating the knob of the needle valve 7, thereby finely adjusting the pressure inside the pipeline to the set value required for the experiment; when there is an abnormal increase in the pipeline pressure or other emergency situations, the operator can quickly open the needle valve 7 and rapidly reduce the pressure inside the pipeline by rotating the knob by a large margin to prevent the pipeline from bursting or other safety accidents from occurring.

[0041] Specifically, by observing the pressure currently reflected by the data acquisition instrument 19, if the current pressure is equal to the pressure required for the experiment, then open the needle valve 7 and slowly relieve the pressure to the pressure required for the experiment; if the current pressure is lower than the pressure required for the experiment, then open the high-pressure liquefied gas insertion cylinder 1 and the liquid booster pump 3, observe the outlet pressure of the liquid booster pump 3, and when the outlet pressure of the liquid booster pump 3 reaches the first experimental pressure, open the pneumatic ball valve 5. At this time, the liquid booster pump 3 replenishes the pressure of the experimental pipeline. Observe the pressure reflected by the data acquisition instrument 19 here. When the pressure rises to the first experimental pressure, close the first pneumatic ball valve 5, the liquid booster pump 3, and the high-pressure liquefied gas insertion cylinder 1; let it stand for 5 minutes. When the pressure is stable, confirm whether the pressure inside the experimental pipeline is equal to the pressure required for the experiment.

[0042] Furthermore, as Figure 3 shown, the movable relief port 10 is movably connected to any short pipe 81 of the experimental pipeline. A groove 8300 is provided at the middle position of the movable relief port 10. As Figure 4 shown, the bottom of the groove 8300 is used to install orifice plates 8400 with different apertures and shapes. The orifice plates are provided with relief holes. The groove 8300 is connected and installed with a third pneumatic ball valve 11 through a thread 8100. The movable relief port 10 controls the pressure relief of the high-pressure liquefied gas to the pressure required for the experiment through the third pneumatic ball valve 11.

[0043] It should be noted that the movable relief port 10 is made of 304 stainless steel and has a circular pipe inside, with a cross-sectional area identical to that of the short pipe 81 and the joint 82. By placing the orifice plate 8400 in the groove at the top of the movable relief port 10, the purpose is to make the orifice plate 8400 as close as possible to the pipe wall surface, so as to more accurately and realistically simulate the leakage situation of a hole in the pipe wall, resulting in a sudden drop in the pressure of the liquefied gas in the pipe. If the high-pressure liquefied fluid first flows through the third pneumatic ball valve 11 and then through the orifice plate to communicate with the outside, the flow flashing phenomenon caused by the sudden pressure drop may occur inside the third pneumatic ball valve 11 and cannot be observed and recorded.

[0044] Furthermore, as Figure 5 shown, the movable window 9 is movably connected to any short pipe 81 of the experimental pipe. Among them, in the side view of the movable window 9 as Figure 6 shown, the movable window 9 includes a flange 901, a high-transparency organic glass 902, and a main structure 903. The center of the flange 901 is provided with an opening, and the high-transparency organic glass 902 is fixedly connected to the main structure 903 by bolts; the high-speed camera 20 is installed directly in front of the movable window 9 for observing the high-pressure liquefied gas in the experimental pipe, and the pressure data of the high-pressure liquefied gas is observed through the data acquisition instrument 19. After the pressure data no longer decreases, the data recording is stopped to complete the pressure relief experiment.

[0045] It should be noted that, in the other side view of the movable window 9 as Figure 7 shown, the cross-section of the pipe inside the main structure 903 is rectangular, which is used to observe the flow conditions on the upper and lower walls of the experimental pipe. The rectangular area is the same as the cross-sectional area of the short pipe and the joint 8 to ensure the same mass flow rate at all parts of the experimental pipe; the height (h) and width (l) of the protruding part of the high-transparency organic glass 902 are equal to the height (h) and width (l) of the window opening on the main structure 903 and the opening of the flange 901, and the thickness of the protruding part is the same as the wall thickness of the window opening on the main structure 903, which is beneficial to the smoothness of the inner wall surface of the pipe inside the main mechanism 903; the four through holes of the movable window 9 for installing sensors are respectively fixed in the vertical direction directly above and directly below. In this way, before the actual experiment, the movable window 9 can freely adjust its installation position in the experimental pipe, and after the installation is completed, the experimental materials can be filled into the experimental pipe to enable a dead-angle-free observation of the liquid in the experimental pipe in the observation area.

[0046] Specifically, by adjusting the high-speed camera, the final confirmation before the experiment is carried out, and the control computer 16, T temperature sensor 17, P pressure sensor 18, and data acquisition instrument 19 are set to record data; during the pressure relief, observe the pressure data reflected by the data acquisition instrument 19. When the pressure no longer decreases, stop data recording and back up the data to complete the relief experiment. At the same time, open the thermal insulation material 14, remove the heating tape 12, and wind the silica gel hose of the refrigeration device 13 around the experimental pipeline for temperature reduction treatment.

[0047] Furthermore, the data acquisition device further includes a power distribution cabinet 15. The power distribution cabinet 15 is respectively connected to the data acquisition instrument 19 and the control computer 16. The power distribution cabinet 15 is also connected to the heating tape 12 and the refrigeration device 13 of the experimental pipeline system for supplying power to the connection devices of the data acquisition device and the experimental pipeline system.

[0048] It should be noted that the power distribution cabinet 15 controls the start and stop of the heating tape 12 and the refrigeration device 13 through software, providing a stable and reliable power supply for the experiment.

[0049] In an embodiment, the research experimental steps for the flow flashing characteristics of high-pressure liquefied pipelines include: Combine the experimental pipeline and install a relief orifice plate and a relief ball valve; Install the data acquisition device: Install the T temperature sensor 17 and the P pressure sensor 18 at several through holes of the joint 82 and the movable window 9, connect each sensor to the data acquisition instrument 19, connect the data acquisition instrument 19 to the control computer 16, and set up a high-speed camera 20 in front of the movable window 9; Conduct an airtightness inspection, wind the heating tape 12 and cover the thermal insulation material 14: The heating tape 12 is a fiberglass electric heating tape, wound outside the experimental pipeline. The thermal insulation material 14 is nitrile rubber heat insulation cotton, and the nitrile rubber heat insulation cotton is wrapped around the experimental pipeline to insulate the experimental pipeline from the outside; Fill the pipeline with experimental materials: Open the high-pressure liquefied gas insertion steel cylinder 1, open the first pneumatic ball valve 5, and the liquid flows into the pipeline. Here, observe the pressure change through the data acquisition instrument 19. After the pressure stops rising, let it stand for 2 minutes, and then close the first pneumatic ball valve 5 and the high-pressure liquefied gas insertion steel cylinder 1; Adjust the experimental temperature: Turn on the heating tape 12 to heat the experimental pipeline. Here, observe the data acquisition instrument 19. When the temperature rises to the expected experimental temperature, turn off the heating tape 12; Adjust the pressure of the experimental pipeline to the required pressure for the experiment; Record the experimental data: By adjusting the high-speed camera, conduct the final confirmation before the experiment, and set the control computer 16, T temperature sensor 17, P pressure sensor 18, and data acquisition instrument 19 to record data; Perform pressure relief: Open the third pneumatic ball valve 11 to perform pressure relief; Complete the relief experiment and perform temperature reduction treatment: Observe the pressure data reflected by the data acquisition instrument 19. When the pressure no longer decreases, stop data recording and back up the data to complete the relief experiment. At the same time, open the thermal insulation material 14, remove the heating tape 12, wind the silica gel hose of the refrigeration equipment 13 around the experimental pipeline, and perform temperature reduction treatment.

[0050] In this embodiment, by combining the experimental pipeline, it is ensured that the use conditions can be accurately controlled according to the experimental requirements; through airtightness inspection, the safety and reliability of the experimental device during the transmission of high-pressure liquefied gas are ensured to prevent gas leakage; by winding the heating tape and covering the thermal insulation material, the temperature conditions in the actual experimental process can be simulated to study the influence of temperature on the flow characteristics of high-pressure liquefied gas; through various sensors and data acquisition instruments, the temperature and pressure changes during the experimental process can be monitored and recorded in real time; by adjusting the pressure and temperature of the experimental pipeline, the flow characteristics and phase change behavior of high-pressure liquefied gas in the pipeline can be studied, such as the flashing phenomenon of high-pressure liquefied gas; through the movable viewing window and high-speed camera with freely adjustable positions, the flow state and phase change process of the liquid in the pipeline can be visually observed, which helps to improve the understanding of fluid behavior; by installing a relief orifice plate and a relief ball valve, the pressure in the pipeline can be safely controlled to simulate leakage or pressure reduction situations and study the behavior and changes of high-pressure liquefied gas under these conditions; by simulating the process of flow flashing caused by a sudden drop in pressure in the high-pressure liquefied pipeline, it is beneficial to further understand the disaster-causing process of high-pressure liquefied pipeline leakage and improve the safe operation level of the pipeline.

[0051] This application also proposes a research method for pipeline flow flashing characteristics based on a pipeline flow flashing characteristics research device, which is applied to the pipeline flow flashing characteristics research device. The research method for pipeline flow flashing characteristics based on the pipeline flow flashing characteristics research device includes: Open the pneumatic ball valve of the high-pressure liquefied gas insertion cylinder of the gas supply device to fill the experimental pipeline with high-pressure liquefied gas; Heat the experimental pipeline through the heating tape, and observe the temperature through the data acquisition instrument of the data acquisition device to reach the experimental temperature; Observe whether the current pressure of the experimental pipeline reaches the required experimental pressure through the data acquisition instrument; When the current pressure of the experimental pipeline is equal to the required experimental pressure, open the pneumatic ball valve on the movable pressure relief valve of the experimental pipeline system to perform pressure relief; Observe the pressure data through the data acquisition device. After the pressure data no longer decreases, stop recording the data and complete the pressure relief experiment.

[0052] The research method of the pipeline flow flashing characteristics of the pipeline flow flashing characteristics research device involved in this application simulates the process of flow flashing caused by a sudden pressure drop due to the pressure release of high-pressure liquefied gas in a high-pressure liquefied pipeline by setting up a gas supply device, an experimental pipeline system, and a data acquisition device. During the simulation of the experimental pipeline, the experimental pipeline system is supplied with gas by the gas supply device. The experimental pipeline system accommodates the high-pressure liquefied gas provided by the gas supply device. The high-pressure liquefied gas is heated to the expected experimental temperature by the heating tape of the experimental pipeline system. Whether the current pressure of the experimental pipeline reaches the required experimental pressure is observed through a data acquisition instrument. When the current pressure of the experimental pipeline is equal to the required experimental pressure, a movable relief port can be used to simulate a small hole leakage on the pipeline wall surface, resulting in a sudden pressure drop, and a high-speed camera installed at the movable viewing window is used to observe the flow flashing phenomenon. The data acquisition device is used to collect and monitor the experimental data of the experimental pipeline system. Through the research on the disaster-causing process of pressure release, the behavior of high-pressure liquefied pipelines during sudden pressure drops can be better understood, providing a scientific basis for improving the safe operation of pipelines.

[0053] Thus, the research method of the pipeline flow flashing characteristics of the pipeline flow flashing characteristics research device involved in the technical solution of this application can simulate the process of flow flashing caused by a sudden pressure drop in a high-pressure liquefied pipeline. By using a movable relief port to simulate a small hole leakage on the pipeline wall surface, the leakage situation that may occur in an actual pipeline can be reproduced, so as to study the sudden pressure drop and flow flashing phenomenon caused by the leakage. The design of the movable viewing window allows researchers to directly observe the flow flashing phenomenon. Combined with the data acquisition device, key parameters during the experimental process, such as pressure, temperature, flow rate, etc., can be recorded in real time. Aiming at the lack of the ability to solve the phase change control problem when the pipeline pressure suddenly decreases in the prior art, it is beneficial to further understand the disaster-causing process of high-pressure liquefied pipeline leakage. Through the accumulation and analysis of experimental data, it can provide guidance for pipeline operation and maintenance, reduce potential safety risks, and improve the safe operation level of pipelines.

[0054] The above are only partial embodiments of this application, and do not limit the patent scope of this application accordingly. Any equivalent structural transformation made under the technical concept of this application by using the content of the specification and drawings of this application, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of this application.

Claims

1. A device for studying the flashing characteristics of pipeline flow, characterized in that The research device for the flash evaporation characteristics of pipeline flow includes: A gas supply device, which is connected to the experimental pipeline system and is used to fill the experimental pipeline with high-pressure liquefied gas. An experimental pipeline system, which is used to heat the experimental pipeline and release pressure when the current pressure of the experimental pipeline is equal to the required pressure for the experiment. A data acquisition device, which is connected to the experimental pipeline system and is used to observe the temperature of the experimental pipeline to reach the experimental temperature, and to observe whether the current pressure of the experimental pipeline reaches the required pressure for the experiment; after the pressure is released, observe the pressure data, and stop recording data after the pressure data no longer decreases, thus completing the pressure release experiment.

2. The research device for the flash evaporation characteristics of pipeline flow according to claim 1, characterized in that, The gas supply device includes a high-pressure liquefied gas inserting cylinder, a high-pressure liquefied gas ordinary cylinder, a liquid booster pump, a gas guide pipe, a first pneumatic ball valve and a second pneumatic ball valve. The liquid booster pump is installed at the connection between the high-pressure liquefied gas inserting cylinder and the first pneumatic ball valve. The other end of the first pneumatic ball valve is connected to the gas guide pipe. The high-pressure liquefied gas ordinary cylinder is connected to the gas guide pipe through the second pneumatic ball valve. The gas supply device is connected to the experimental pipeline of the experimental pipeline system through the gas guide pipe, and the first pneumatic ball valve of the high-pressure liquefied gas inserting cylinder is used to fill the experimental pipeline with high-pressure liquefied gas.

3. The research device for the flash evaporation characteristics of pipeline flow according to claim 2, characterized in that, The experimental pipeline system includes: An experimental pipeline, which is composed of several groups of short pipes connected by joints; a movable window, a movable relief port and a needle valve are provided on the experimental pipeline. The joints and the movable window are both provided with several through holes for installing sensors; a heating tape, heat insulation material and refrigeration equipment are also provided on the outer surface of the experimental pipeline, and the experimental pipeline is heated by the heating tape.

4. The device for studying the flashing characteristics of pipeline flow according to claim 3, characterized in that The heating tape is wound around the outer surface of the experimental pipeline and is used to increase the temperature of the high-pressure liquefied gas; the refrigeration equipment includes a refrigerator and a silica gel hose. The coolant of the refrigerant flows into the silica gel hose, and the silica gel hose is wound around the outer surface of the experimental pipeline and is used to reduce the temperature of the high-pressure liquefied gas through the coolant inside the silica gel hose; the heat insulation material wraps the heating tape or the refrigeration equipment and is wound around the outer surface of the experimental pipeline to perform heat insulation treatment on the experimental pipeline and adjust the temperature of the high-pressure liquefied gas in the experimental pipeline to the expected experimental temperature.

5. The research device for the flashing characteristics of pipeline flow according to claim 3 or 4, characterized in that, The data acquisition device includes a temperature sensor, a pressure sensor, a data acquisition instrument, a high-speed camera and a control computer; the temperature sensor and the pressure sensor are both installed at several through holes of the joints and the movable window. The data acquisition instrument collects the data of the temperature sensor and the pressure sensor and is connected to the control computer through a special data cable, and is used to observe the temperature of the experimental pipeline to reach the experimental temperature, and to observe whether the current pressure of the experimental pipeline reaches the required pressure for the experiment.

6. The device for studying the flashing characteristics of pipeline flow according to claim 5, wherein The needle valve is fixedly connected directly above the nearest group of short pipes at the connection between the experimental pipeline and the gas supply device, and the needle valve is used to control the flow rate of the high-pressure liquefied gas to adjust the pressure of the experimental pipeline to the required pressure for the experiment.

7. The research device for the flash evaporation characteristics of pipeline flow according to claim 6, characterized in that, The movable relief opening is movably connected to any short pipe of the experimental pipeline. A groove is provided at the middle position of the movable relief opening. The bottom of the groove is used to install orifice plates with different apertures and shapes. The orifice plate is provided with a relief hole. The groove is installed with a third pneumatic ball valve through threaded connection. The movable relief opening controls the pressure relief of the required pressure for the experiment of the high-pressure liquefied gas through the third pneumatic ball valve.

8. The device for studying the flashing characteristics of pipeline flow according to claim 5, characterized in that The movable viewing window is movably connected to any short pipe of the experimental pipeline. The movable viewing window includes a flange, a high-transparency organic glass, and a main structure. A central opening is provided on the flange, and the high-transparency organic glass is fixedly connected to the main structure through bolts. The high-speed camera is installed directly in front of the movable viewing window to observe the high-pressure liquefied gas in the experimental pipeline. And the pressure data of the high-pressure liquefied gas is observed through the data acquisition instrument. After the pressure data no longer decreases, stop recording the data to complete the pressure relief experiment.

9. The research device for the flash evaporation characteristics of pipeline flow according to claim 5, wherein, The data acquisition device further includes a power distribution cabinet. The power distribution cabinet is respectively connected to the data acquisition instrument and the control computer. The power distribution cabinet is also connected to the heating tape and the refrigeration equipment of the experimental pipeline system for supplying power to the connection equipment of the data acquisition device and the experimental pipeline system.

10. A method for studying the pipeline flow flashing characteristics based on a research device for pipeline flow flashing characteristics, characterized in that, The method for studying the pipeline flow flashing characteristics of the device for studying pipeline flow flashing characteristics is applied to the device for studying pipeline flow flashing characteristics according to any one of claims 1 to 9. The method for studying pipeline flow flashing characteristics includes: Open the first pneumatic ball valve of the high-pressure liquefied gas insertion cylinder of the gas supply device to fill the experimental pipeline with high-pressure liquefied gas; Heat the experimental pipeline through the heating tape, and observe the temperature through the data acquisition instrument of the data acquisition device to reach the experimental temperature; Observe through the data acquisition instrument whether the current pressure of the experimental pipeline reaches the required pressure for the experiment; When the current pressure of the experimental pipeline is equal to the required pressure for the experiment, open the pneumatic ball valve on the movable pressure relief valve of the experimental pipeline system to conduct pressure relief; Observe the pressure data through the data acquisition device. After the pressure data no longer decreases, stop recording the data to complete the pressure relief experiment.

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