System and method for acquiring propagation velocity change rule in pressure wave attenuation process

Abstract

The invention relates to the field of pipeline transportation flow safety, and discloses a system and a method for acquiring a propagation velocity change rule in a pressure wave attenuation process, and the system comprises a pipeline system which comprises an annular pipeline formed by connecting a plurality of straight pipes and bent pipes end to end, an external thread interface is reserved on the pipe wall, and a branch pipeline is arranged on one side of the annular pipeline; the pressure wave generation system, the pressure wave detection system, the temperature and pressure control system and the temperature and pressure detection system are all in threaded connection to the annular pipeline through external thread connectors so as to obtain the propagation speed change rule in the pressure wave attenuation process. The change rule of the pressure wave propagation speed along with the amplitude can be obtained, and the accuracy and reliability of pipeline anomaly detection are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline transportation flow safety, and in particular to a pipeline system and method for studying changes in propagation velocity during pressure wave attenuation under different environmental conditions. Background Art

[0002] In deepwater oil and gas production sites and modern urban infrastructure, fluid transport pipeline systems (water supply, oil and gas pipelines) are key to maintaining daily operations. Due to their widespread distribution and long-term use, they face problems such as pipeline aging and accumulation of abnormalities, such as leakage, blockage and pipeline wall corrosion. These abnormalities not only lead to a large amount of water resources and energy losses, but also may cause environmental damage and public safety risks.

[0003] Pressure wave detection technology is an effective method for detecting pipeline anomalies. This technology generates high-pressure waves that can propagate along the pipe through the rapid flow changes of the fluid in the pipe. Based on the principle of wave propagation and reflection, a signal inversion model is established to detect abnormal conditions in the pipeline by analyzing the collected data. Pressure waves have the advantages of high propagation speed, long distance, low attenuation, and high tolerance to background noise, which are very suitable for long-distance pipeline detection. In the past three decades, pressure wave-based technology has been widely developed to detect various pipeline anomalies and evaluate the overall condition of the pipeline wall.

[0004] Although significant progress has been made in pressure wave-based detection technology, there are still deficiencies in the study of pressure wave propagation characteristics. In particular, the mechanism and model of the attenuation of pressure wave propagation velocity with amplitude have not been fully studied. In practical applications, the attenuation of pressure waves is not only affected by the pipeline material and structure, but may also be affected by fluid properties and environmental conditions. Therefore, in-depth research on the variation of pressure wave propagation velocity with amplitude is crucial to improve the accuracy and reliability of pipeline anomaly detection. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a system and method for obtaining the law of change of propagation velocity during pressure wave attenuation, which can obtain the law of change of pressure wave propagation velocity with amplitude, thereby improving the accuracy and reliability of pipeline anomaly detection.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a system for obtaining the law of change of propagation velocity during pressure wave attenuation, which includes: a pipeline system, a pressure wave generating system, a pressure wave detection system, a temperature and pressure control system and a temperature and pressure detection system; the pipeline system includes a ring pipeline composed of multiple straight pipes and curved pipes connected end to end, an external threaded interface is left on the pipe wall, and a branch pipeline is arranged on one side of the ring pipeline; the pressure wave generating system, the pressure wave detection system, the temperature and pressure control system and the temperature and pressure detection system are all threadedly connected to the ring pipeline through the external threaded interface to obtain the law of change of propagation velocity during pressure wave attenuation.

[0007] Further, the pressure wave generating system comprises: The normally closed solenoid valve is installed on the branch pipeline through an external threaded interface. The short-term opening action of the normally closed solenoid valve generates a short-term leakage and a negative pressure wave in the annular pipeline. The normally open electromagnetic ball valve is arranged in the middle of the pipeline on the right side of the interface between the branch pipeline and the annular pipeline. By closing the valve before the normally closed electromagnetic valve opens, the generated pressure wave can move in one direction, and before the pressure wave moves to the other end of the normally open electromagnetic ball valve, the normally open electromagnetic ball valve is restored to a fully open state to form a pressure wave that propagates in one direction and continuously decays in the annular pipeline.

[0008] Further, a sound absorbing material is applied on the closing surface of the normally open type electromagnetic ball valve.

[0009] Further, the pressure wave detection system includes: a first dynamic pressure sensor, a second dynamic pressure sensor, a temperature sensor and a data acquisition system arranged on the annular pipeline; When the pressure wave is transmitted along the annular pipeline to the first dynamic pressure sensor and the second dynamic pressure sensor, the two dynamic pressure sensors record the dynamic pressure changes at their detection positions and transmit the data detected by the two sensors to the data acquisition system at the same time; The data acquisition system collects the signals detected by the first dynamic pressure sensor and the second dynamic pressure sensor, uses digital signal processing to obtain the time difference between the pressure wave reaching the first dynamic pressure sensor and the second dynamic pressure sensor, and measures the distance between the detection points of the first dynamic pressure sensor and the second dynamic pressure sensor in advance, and calculates the average speed of the pressure wave when passing through the first dynamic pressure sensor and the second dynamic pressure sensor; then, based on the dynamic pressure changes detected by the first dynamic pressure sensor and the second dynamic pressure sensor, the amplitude attenuation degree of the pressure wave at this time is obtained, and the relationship between the amplitude attenuation degree of the pressure wave and the propagation speed of the pressure wave is established.

[0010] Further, the temperature and pressure control system includes: a chiller, a water inlet pipe, a water bath jacket, a water outlet pipe, an exhaust pipe and an air injection pipe; The water bath jacket is arranged on the outside of the annular pipeline, and the entire annular pipeline is wrapped in the water bath jacket; The chiller is connected to the water bath jacket through the water inlet pipe and the water outlet pipe to control the temperature of the cooling medium in the water bath jacket; the cooling medium in the water bath jacket is in direct contact with the annular pipeline and performs heat exchange; The gas injection pipe and the exhaust pipe are installed on the annular pipeline through external thread interfaces on the annular pipeline.

[0011] Furthermore, one end of the gas injection pipe is connected to the gas cylinder, and the other end of the gas injection pipe is connected to the annular pipeline; a pressure reducing valve is provided on the gas injection pipe; and a back pressure valve is provided on the exhaust pipe; A second check valve and a first check valve are respectively arranged on the gas injection pipe and the gas exhaust pipe.

[0012] Further, the temperature and pressure detection system includes: a temperature sensor and a pressure sensor; The temperature sensor and the pressure sensor respectively detect the temperature and pressure of the fluid in the annular pipeline in real time, and cooperate with the temperature and pressure control system to regulate the temperature and pressure of the fluid in the annular pipeline.

[0013] A method for obtaining a law of change in propagation velocity during pressure wave attenuation is implemented based on the system for obtaining a law of change in propagation velocity during pressure wave attenuation, and includes: Keep the normally closed solenoid valve closed, keep the normally open solenoid ball valve fully open, and connect the branch line to the waste gas bottle; Connect the gas injection pipe to the gas cylinder, open the valve on the gas cylinder, slowly adjust the pressure reducing valve, and inject the corresponding gas into the annular pipeline to the specified pressure; Turn on the chiller to cool the gas in the ring pipeline to the specified temperature; Close the normally open solenoid valve, then control the normally closed solenoid valve to open briefly, and immediately close the normally closed solenoid valve, and then control the normally open solenoid valve to open; coordinate the timing and duration of the valve opening and closing to achieve one-way propagation of the pressure wave and avoid hindering the circulation of the pressure wave in the annular pipeline; When the pressure wave circulates and propagates in the annular pipeline, the first dynamic pressure sensor and the second dynamic pressure sensor transmit the collected dynamic pressure signal to the data acquisition system and complete the calculation of the pressure wave propagation speed; establish a functional relationship model between the pressure wave amplitude and the propagation speed, and perform parameter fitting to obtain an accurate curve describing the change of the pressure wave amplitude with the propagation speed; After the experiment, connect the waste gas bottle to the exhaust pipe, and slowly adjust the back pressure valve to discharge the gas in the annular pipeline to normal pressure.

[0014] Furthermore, the coolant used between the water bath jacket and the chiller is preferably a 50% by volume ethylene glycol solution.

[0015] Furthermore, the branch pipe and the ring pipe are made of carbon steel of API 5L X60 PSL1 and above.

[0016] The present invention adopts the above technical solution, which has the following advantages: 1. The present invention links a normally closed solenoid valve with a normally open solenoid ball valve. Before the normally closed solenoid valve opens to generate a pressure wave, the normally open solenoid ball valve is temporarily closed to block the transmission of the pressure wave in one direction. Before the pressure wave is about to reach a cycle through the annular pipeline, the open state of the normally open solenoid valve is restored, thereby generating a unidirectional circulating and continuously attenuated pressure wave in the annular pipeline, thereby effectively simplifying the difficulty of analyzing the dynamic pressure sensor signal. At the same time, there is no obvious blockage in the pipe, reducing the interference caused by the reflection of the pressure wave.

[0017] 2. The present invention is equipped with a temperature and pressure control system, which can realize the study of the propagation velocity of the pressure wave under different conditions, and is helpful to explore the changing law of the propagation velocity of the pressure wave. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall structure of a system for obtaining the law of change of propagation velocity during the attenuation of pressure waves in an embodiment of the present invention; Reference numerals: 1. Chiller; 2. Water inlet pipe; 3. Water bath jacket; 4. Annular pipeline; 5. Back pressure valve; 6. First check valve; 7. First dynamic pressure sensor; 8. Second dynamic pressure sensor; 9. Temperature sensor; 10. Data acquisition system; 11. Water outlet pipe; 12. Normally closed solenoid valve; 13. Normally open solenoid ball valve; 14. Pressure sensor; 15. Second check valve; 16. Pressure reducing valve; 17. Gas cylinder; 18. Exhaust pipe; 19. Gas injection pipe; 20. Branch pipeline. DETAILED DESCRIPTION

[0019] In order to study the change of pressure wave propagation velocity with amplitude attenuation, the present invention provides a system and method for obtaining the law of change of propagation velocity during pressure wave attenuation, so as to realize the study of pressure wave propagation velocity under different conditions, which is helpful to explore the law of change of pressure wave propagation velocity and improve the accuracy and reliability of pipeline anomaly detection.

[0020] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0022] Embodiment 1: In this embodiment of the present invention, a system for obtaining the law of propagation velocity change during the attenuation of pressure waves is provided. In this embodiment, Figure 1 As shown, the system includes: a pipeline system, a pressure wave generating system, a pressure wave detecting system, a temperature and pressure control system and a temperature and pressure detecting system.

[0023] The pipeline system includes a ring pipeline 4 formed by connecting a plurality of straight pipes and curved pipes end to end, with an external threaded interface left on the pipe wall, and a branch pipeline 20 is arranged on one side of the ring pipeline 4; The pressure wave generating system, the pressure wave detecting system, the temperature and pressure control system and the temperature and pressure detecting system are all threadedly connected to the annular pipeline 4 through an external thread interface to obtain the changing law of the propagation speed during the attenuation of the pressure wave.

[0024] In the above embodiment, optionally, eight 1 / 2 NPT external thread interfaces are left on the pipe wall of the annular pipeline 4 for connecting sensors, solenoid valves and inlet and outlet valves.

[0025] In the above embodiment, the pressure wave generating system includes: The normally closed solenoid valve 12 is arranged on the branch pipeline 20 through an external threaded interface. The normally closed solenoid valve 12 briefly opens the valve to generate a short-term leakage, thereby generating a negative pressure wave in the annular pipeline 4.

[0026] The normally open electromagnetic ball valve 13 is arranged in the middle of the pipeline on the right side of the interface between the branch pipeline 20 and the annular pipeline 4. By closing the valve before the normally closed electromagnetic valve 12 opens the valve, the generated pressure wave can move in one direction. Before the pressure wave moves to the other end of the normally open electromagnetic ball valve 13, the normally open electromagnetic ball valve 13 is restored to a fully open state, thereby forming a unidirectionally propagating and continuously attenuating pressure wave in the annular pipeline.

[0027] The sound absorbing material is applied on the closing surface of the normally open electromagnetic ball valve 13 to weaken the reflection of the pressure wave and the vibration of the pressure wave propagating through the valve body to the other end.

[0028] Optionally, the sound-absorbing material covering the closing surface of the normally open electromagnetic ball valve 13 is preferably an inorganic fiber material, such as glass wool.

[0029] In the above embodiment, the pressure wave detection system includes: a first dynamic pressure sensor 7, a second dynamic pressure sensor 8, a temperature sensor 9 and a data acquisition system 10 arranged on the annular pipeline 4. When the pressure wave is transmitted along the annular pipeline 4 to the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8, the two dynamic pressure sensors will record the dynamic pressure changes at their detection positions and transmit the data detected by the two to the data acquisition system 10.

[0030] The data acquisition system 10 acquires the signals detected by the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8, and obtains the time difference between the pressure wave reaching the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8 by digital signal processing. , and measure in advance the distance between the detection points of the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8 , calculate the average velocity of the pressure wave when it passes through the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8 .

[0031]

[0032] Then, the amplitude attenuation degree of the pressure wave at this time is obtained according to the dynamic pressure changes detected by the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8, and the relationship between the amplitude attenuation degree of the pressure wave and the propagation speed of the pressure wave is further established.

[0033] In this embodiment, the distance between the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8 is set to 5 m, which is convenient for calculating the propagation velocity of the pressure wave.

[0034] In the above embodiment, the temperature and pressure control system includes: a chiller 1 , a water inlet pipe 2 , a water bath jacket 3 , a water outlet pipe 11 , an exhaust pipe 18 and an air injection pipe 19 .

[0035] The water bath jacket 3 is arranged on the outside of the annular pipeline 4 , and the entire annular pipeline 4 is wrapped in the water bath jacket 3 .

[0036] The chiller 1 is connected to the water bath jacket 3 through the water inlet pipe 2 and the water outlet pipe 11 to control the temperature of the cooling medium in the water bath jacket 3. The cooling medium in the water bath jacket 3 is in direct contact with the annular pipeline 4 and performs heat exchange to control the temperature of the fluid in the annular pipeline 4.

[0037] The gas injection pipe 19 and the exhaust pipe 18 are installed on the annular pipeline 4 through external thread interfaces on the annular pipeline 4 .

[0038] In this embodiment, one end of the gas injection pipe 19 is connected to the gas cylinder 17, and the other end of the gas injection pipe 19 is connected to the annular pipeline 4. The gas injection pipe 19 is provided with a pressure reducing valve 16, and the high-pressure gas in the gas cylinder 17 is allowed to enter the annular pipeline 4 by adjusting the opening of the pressure reducing valve 16 to control the gas pressure in the pipeline. The exhaust pipe 18 is provided with a back pressure valve 5. When the test is completed or the gas pressure in the annular pipeline 4 is too high, the gas is discharged into the waste gas bottle by adjusting the back pressure valve 5 on the exhaust pipe 18 to control the gas pressure in the pipeline.

[0039] A second check valve 15 and a first check valve 6 are respectively provided on the gas injection pipe 19 and the gas exhaust pipe 18 to prevent gas leakage.

[0040] In the above embodiment, the temperature and pressure detection system includes: a temperature sensor 9 and a pressure sensor 14. The temperature sensor 9 and the pressure sensor 14 respectively detect the temperature and pressure of the fluid in the annular pipeline 4 in real time, and cooperate with the temperature and pressure control system to regulate the temperature and pressure of the fluid in the annular pipeline 4.

[0041] Embodiment 2: In this embodiment of the present invention, a method for obtaining the law of change of propagation velocity during pressure wave attenuation is provided. The method is implemented based on the system for obtaining the law of change of propagation velocity during pressure wave attenuation in the above embodiments. In this embodiment, the method includes the following steps: 1) Keep the normally closed solenoid valve 12 closed and the normally open solenoid ball valve 13 fully open; and connect the branch line 20 to the waste gas bottle to collect the gas overflowed in the subsequent short-term leakage operation.

[0042] 2) Connect the gas injection pipe 19 to the gas cylinder 17, open the valve on the gas cylinder 17, slowly adjust the pressure reducing valve 16, and inject the corresponding gas into the annular pipeline 4 to the specified pressure.

[0043] 3) Turn on the chiller 1 to cool the gas in the ring pipeline 4 to the specified temperature.

[0044] 4) Close the normally open electromagnetic ball valve 13, then control the normally closed electromagnetic valve 12 to produce a short valve opening action, and immediately close the normally closed electromagnetic valve 12, and then control the normally open electromagnetic ball valve 13 to open. Coordinate the timing and duration of the valve opening and closing to achieve unidirectional propagation of the pressure wave and avoid hindering the circulation propagation of the pressure wave in the annular pipeline 4.

[0045] 5) When the pressure wave circulates and propagates in the annular pipeline 4, the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8 transmit the collected dynamic pressure signal to the data acquisition system 10 and complete the calculation of the pressure wave propagation velocity. A functional relationship model between the pressure wave amplitude and the propagation velocity is established, and parameter fitting is performed to obtain an accurate curve describing the change of the pressure wave amplitude with the propagation velocity.

[0046] 6) After the experiment, connect the waste gas bottle to the exhaust pipe 18, and slowly adjust the back pressure valve 5 to discharge the gas in the annular pipeline 4 to normal pressure.

[0047] In the above embodiment, the coolant used between the water bath jacket 3 and the chiller 1 is preferably a 50% by volume ethylene glycol solution to obtain better cold storage performance.

[0048] In the above embodiment, the branch pipeline 20 and the annular pipeline 4 are preferably made of carbon steel of grade API 5L X60 PSL1 or above.

[0049] In the above embodiment, the distance between the first dynamic pressure sensor 7 and the second dynamic pressure sensor 8 is set to 5 m, which is convenient for calculating the pressure wave propagation velocity.

[0050] In the above embodiment, the total length of the annular pipeline 4 is set to 50m. Taking the sound speed of 340m / s at room temperature as an example, it takes about 147ms for the pressure wave to propagate one circle along the pipe, which facilitates the cooperation between the normally closed solenoid valve 12 and the normally open solenoid ball valve 13 to generate a unidirectional pressure wave.

[0051] In the above embodiment, the duration of the short-term opening of the normally closed electromagnetic valve 12 is set to 10ms. After the valve of the normally closed electromagnetic valve 12 is closed, the normally open electromagnetic ball valve 13 maintains the closed valve state for 50ms before opening. This allows the sound-absorbing material to fully absorb the pressure wave and leaves enough time to fully open the normally open electromagnetic ball valve 13, thereby avoiding the influence of the ball valve on the propagation of the pressure wave.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for obtaining the law of change of propagation velocity during pressure wave attenuation, characterized in that: include: Pipeline system, pressure wave generating system, pressure wave detecting system, temperature and pressure control system and temperature and pressure detecting system; The pipeline system comprises a plurality of straight pipes and curved pipes connected end to end to form an annular pipeline (4), an external threaded interface is left on the pipe wall, and a branch pipeline (20) is arranged on one side of the annular pipeline (4); The pressure wave generating system, the pressure wave detecting system, the temperature and pressure control system and the temperature and pressure detecting system are all threadedly connected to the annular pipeline (4) via an external thread interface to obtain the law of change of propagation speed during the attenuation process of the pressure wave.

2. The system for obtaining the law of change of propagation velocity during pressure wave attenuation according to claim 1, characterized in that: The pressure wave generating system includes: A normally closed electromagnetic valve (12) is arranged on the branch pipeline (20) via an external threaded interface, and a short-term leakage is generated by a short-term opening action of the normally closed electromagnetic valve (12), thereby generating a negative pressure wave in the annular pipeline (4); The normally open electromagnetic ball valve (13) is arranged in the middle of the pipeline on the right side of the interface between the branch pipeline (20) and the annular pipeline (4); by closing the valve before the normally closed electromagnetic valve (12) opens the valve, the generated pressure wave is allowed to move in one direction, and before the pressure wave moves to the other end of the normally open electromagnetic ball valve (13), the normally open electromagnetic ball valve (13) is restored to a fully open state, so as to form a pressure wave that propagates in one direction and continuously decays in the annular pipeline.

3. The system for obtaining the law of change of propagation velocity during pressure wave attenuation as claimed in claim 2, characterized in that: Apply sound absorbing material to the closing surface of the normally open type solenoid ball valve (13).

4. The system for obtaining the variation law of propagation velocity during the attenuation of pressure waves according to claim 1, characterized in that: The pressure wave detection system comprises: a first dynamic pressure sensor (7), a second dynamic pressure sensor (8), a temperature sensor (9) and a data acquisition system (10) arranged on the annular pipeline (4); When the pressure wave is transmitted along the annular pipeline (4) to the first dynamic pressure sensor (7) and the second dynamic pressure sensor (8), the two dynamic pressure sensors record the dynamic pressure changes at their detection positions and transmit the data detected by the two sensors to the data acquisition system (10); The data acquisition system (10) acquires the signals detected by the first dynamic pressure sensor (7) and the second dynamic pressure sensor (8), obtains the time difference between the pressure wave reaching the first dynamic pressure sensor (7) and the second dynamic pressure sensor (8) by digital signal processing, measures the distance between the detection points of the first dynamic pressure sensor (7) and the second dynamic pressure sensor (8) in advance, calculates the average speed of the pressure wave when passing through the first dynamic pressure sensor (7) and the second dynamic pressure sensor (8), and then obtains the amplitude attenuation degree of the pressure wave at this time based on the dynamic pressure changes detected by the first dynamic pressure sensor (7) and the second dynamic pressure sensor (8), and establishes the relationship between the amplitude attenuation degree of the pressure wave and the propagation speed of the pressure wave.

5. The system for obtaining the variation law of propagation velocity during the attenuation of pressure waves according to claim 1, characterized in that: The temperature and pressure control system comprises: a chiller (1), a water inlet pipe (2), a water bath jacket (3), a water outlet pipe (11), an exhaust pipe (18) and an air injection pipe (19); The water bath jacket (3) is arranged on the outside of the annular pipeline (4), and the entire annular pipeline (4) is wrapped in the water bath jacket (3); The chiller (1) is connected to the water bath jacket (3) via a water inlet pipe (2) and a water outlet pipe (11) to control the temperature of the cooling medium in the water bath jacket (3); the cooling medium in the water bath jacket (3) is in direct contact with the annular pipeline (4) to perform heat exchange; The gas injection pipe (19) and the exhaust pipe (18) are installed on the annular pipeline (4) through the external threaded interface on the annular pipeline (4).

6. The system for obtaining the law of change of propagation velocity during the attenuation of pressure waves as claimed in claim 5, characterized in that: One end of the gas injection pipe (19) is connected to the gas cylinder (17), and the other end of the gas injection pipe (19) is connected to the annular pipeline (4); a pressure reducing valve (16) is provided on the gas injection pipe (19); and a back pressure valve (5) is provided on the exhaust pipe (18); A second check valve (15) and a first check valve (6) are also provided on the gas injection pipe (19) and the gas exhaust pipe (18), respectively.

7. The system for obtaining the variation law of propagation velocity during the attenuation of pressure waves according to claim 1, characterized in that: The temperature and pressure detection system comprises: a temperature sensor (9) and a pressure sensor (14); The temperature sensor (9) and the pressure sensor (14) respectively detect the temperature and pressure of the fluid in the annular pipeline (4) in real time, and cooperate with the temperature and pressure control system to regulate the temperature and pressure of the fluid in the annular pipeline (4).

8. A method for obtaining a law of change in propagation velocity during pressure wave attenuation, based on the system for obtaining a law of change in propagation velocity during pressure wave attenuation as claimed in any one of claims 1 to 7, characterized in that: include: Keep the normally closed solenoid valve (12) closed, keep the normally open solenoid ball valve (13) fully open, and connect the branch pipe (20) to the waste gas bottle; Connect the gas injection pipe (19) to the gas cylinder (17), open the valve on the gas cylinder (17), slowly adjust the pressure reducing valve (16), and inject the corresponding gas into the annular pipeline (4) to a specified pressure; Turn on the chiller (1) to cool the gas in the annular pipeline (4) to a specified temperature; The normally open electromagnetic ball valve (13) is closed, and then the normally closed electromagnetic valve (12) is controlled to produce a short valve opening action, and the normally closed electromagnetic valve (12) is immediately closed, and then the normally open electromagnetic ball valve (13) is controlled to open; the timing and duration of the valve opening and closing are coordinated to achieve unidirectional propagation of the pressure wave and avoid hindering the circulation propagation of the pressure wave in the annular pipeline (4); When the pressure wave circulates and propagates in the annular pipeline (4), the first dynamic pressure sensor (7) and the second dynamic pressure sensor (8) transmit the collected dynamic pressure signals to the data acquisition system (10) and complete the calculation of the pressure wave propagation speed; establish a functional relationship model between the pressure wave amplitude and the propagation speed, and perform parameter fitting to obtain an accurate curve describing the change of the pressure wave amplitude with the propagation speed; After the experiment, the waste gas bottle is connected to the exhaust pipe (18), and the gas in the annular pipeline (4) is discharged to normal pressure by slowly adjusting the back pressure valve (5).

9. The method for obtaining the variation law of propagation velocity during the attenuation of pressure waves according to claim 8, characterized in that: The coolant used between the water bath jacket and the chiller is preferably a 50% by volume ethylene glycol solution.

10. The method for obtaining the variation law of propagation velocity during the attenuation of pressure waves according to claim 8, characterized in that: The branch pipe and ring pipe are made of carbon steel of API 5L X60 PSL1 and above.

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