A test system for simulating water hammer and thermal shock coupling effect of LNG flexible pipeline on-off valve

Abstract

The application relates to the technical field of LNG pipeline test equipment, and discloses a test system for simulating the coupling effect of water hammer and thermal shock of an LNG flexible pipeline switch valve, which comprises low-temperature pressure gauges YB1-YB6, low-temperature flowmeters LL1-LL2, temperature sensors W1-W4, stop valves F1-F4, an electric switch valve F5, a pneumatic regulating valve F6, a pressure relief valve F7, a safety valve F8, a gas exhaust valve F9, a liquid discharge valve F10, an LNG storage tank C01, a low-temperature pump B01, a refrigerating unit ZL01, a heating module JR01, a constant-temperature buffer tank G01, a flexible test pipeline GDD01, a control box K1, a display storage module SS1 and a data acquisition module CJ01. The utility model is adapted to the low-temperature working condition of LNG, can synchronously simulate the water hammer effect and the thermal shock effect caused by the action of the switch valve, has the advantages of compact structure, simple operation, accurate data acquisition and the like, and can provide test support for the safe design of the LNG flexible pipeline.

Description

Technical Field

[0001] This application relates to the field of LNG pipeline testing equipment technology, and in particular to a testing system for simulating the coupling effect of water hammer and thermal shock on / off valves in LNG flexible pipelines. Background Technology

[0002] LNG flexible pipelines are widely used in LNG receiving terminals, transport ships, and refueling stations due to their advantages such as high flexibility, convenient installation, and vibration resistance. In actual operation, rapid valve switching can easily trigger water hammer effects in the pipeline, causing sudden increases and decreases in pressure. At the same time, the low-temperature characteristics of LNG and the thermal shock caused by changes in ambient temperature and fluctuations in LNG temperature can generate thermal stress in the pipeline material. The coupled effect of these two factors can easily lead to pipeline fatigue damage, seal failure, and other safety hazards.

[0003] Existing testing equipment mostly simulates water hammer or thermal shock effects separately, lacking a dedicated testing system capable of simultaneously simulating the coupled effects of the two. Furthermore, ordinary water hammer test benches are not suitable for the cryogenic conditions of LNG, making it difficult to realistically reproduce actual operating scenarios. Therefore, there is an urgent need to design a testing system adapted to cryogenic conditions that can simultaneously simulate the coupled effects of water hammer and thermal shock, providing support for the structural optimization and safety assessment of LNG flexible pipelines. Utility Model Content

[0004] This invention addresses the problem that existing equipment cannot synchronously simulate coupling effects and adapt to low-temperature operating conditions by providing a test system for simulating the coupling effect of water hammer and thermal shock on the switching valve of an LNG flexible pipeline.

[0005] The objective of this utility model is mainly achieved through the following solution:

[0006] A test system for simulating the coupling effect of water hammer and thermal shock in the switching valve of a flexible LNG pipeline includes a cryogenic detection component, a valve assembly, a medium circulation and temperature control component, a control and acquisition component, and a flexible test carrier.

[0007] The low-temperature detection component is used to collect pressure, flow and temperature data in the pipeline in real time, including a first low-temperature pressure gauge, a second low-temperature pressure gauge, a third low-temperature pressure gauge, a fourth low-temperature pressure gauge, a fifth low-temperature pressure gauge, a sixth low-temperature pressure gauge, a first low-temperature flow meter, a second low-temperature flow meter, a first temperature sensor, a second temperature sensor, a third temperature sensor and a fourth temperature sensor.

[0008] The valve assembly is used for pipeline on / off, flow regulation and pressure protection, including a first shut-off valve, a second shut-off valve, a third shut-off valve, a fourth shut-off valve, an electric switching valve, a pneumatic regulating valve, a pressure relief valve, a safety valve, a venting valve and a drain valve;

[0009] The medium circulation and temperature control components are used to provide a stable cryogenic LNG medium and realize circulation and temperature gradient regulation, including LNG storage tank, cryogenic pump, refrigeration unit, heating module and constant temperature buffer tank;

[0010] The control and acquisition component is used to control the operation of each component and data processing, including a control box, a display and storage module, and a data acquisition module;

[0011] The flexible test carrier is used to bear the coupling effect test of water hammer and thermal shock, and is a flexible test pipeline.

[0012] Preferably, the LNG storage tank is equipped with a vent valve at the top and a drain valve at the bottom, and is connected to a refrigeration unit;

[0013] The LNG storage tank is connected to the input end of the cryogenic pump via a first pipeline, on which a first shut-off valve, a first cryogenic pressure gauge, and a first temperature sensor are installed in sequence. The output end of the cryogenic pump is connected to a constant temperature buffer tank via a second pipeline, on which a second shut-off valve, a first cryogenic flow meter, a second cryogenic pressure gauge, and a second temperature sensor are installed in sequence.

[0014] The constant temperature buffer tank has a built-in heating module; the constant temperature buffer tank is connected to one end of the flexible test pipeline through a third pipeline, on which an electric switch valve is installed, and a third low temperature pressure gauge and a third temperature sensor are respectively installed on both sides; the other end of the flexible test pipeline is connected to the LNG storage tank through a fourth pipeline to form a closed loop circulation, on which a second low temperature flow meter, a third shut-off valve, a fourth low temperature pressure gauge, and a fourth temperature sensor are installed in sequence.

[0015] Preferably, the pneumatic regulating valve is connected in parallel to both ends of the electric switching valve; one end of the pressure relief valve is connected to the third pipeline, and the other end is connected to the exhaust gas recovery branch, for releasing the overpressure generated by water hammer impact; the safety valve is installed on the top of the constant temperature buffer tank to prevent the pressure inside the tank from being too high.

[0016] Preferably, the data acquisition module is electrically connected to the first low-temperature pressure gauge, the second low-temperature pressure gauge, the third low-temperature pressure gauge, the fourth low-temperature pressure gauge, the fifth low-temperature pressure gauge, the sixth low-temperature pressure gauge, the first low-temperature flow meter, the second low-temperature flow meter, the first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor, respectively, for real-time acquisition of pressure, flow, and temperature data. The data acquisition module is also communicatively connected to the display and storage module to realize the display, storage, and export of data.

[0017] The control box is electrically connected to the cryogenic pump, refrigeration unit, heating module, electric switching valve, and pneumatic regulating valve, respectively, and is used to control the start and stop of each component, parameter adjustment, and the operating speed control of the switching valve.

[0018] Preferably, the flexible test pipeline is an LNG-specific flexible hose with an inner diameter of 50-100mm, a pressure resistance of 2.0MPa, and a temperature range of -196℃ to 60℃.

[0019] Preferably, the heating module is a low-temperature resistant electric heating tube with adjustable power from 0 to 5 kW. When used with a refrigeration unit, it can achieve temperature gradient adjustment within the range of -162℃ to -120℃, with a temperature control accuracy of ±1℃.

[0020] Preferably, the electric switching valve is of low temperature explosion-proof type, and the switching time is adjustable from 0.1 to 5 seconds to simulate the water hammer effect at different switching speeds.

[0021] The first, second, third, fourth, fifth, and sixth low-temperature pressure gauges are all shock-resistant low-temperature pressure gauges with a measurement range of 0-2.5 MPa and an accuracy of 0.4 grade.

[0022] The first, second, third, and fourth temperature sensors all use PT100 platinum resistance thermometers with a measurement accuracy of ±0.1℃.

[0023] In summary, compared with the prior art, this utility model has the following beneficial technical effects: the utility model is reasonably designed, cost-controllable, safe and reliable, and easy to operate. It can accurately simulate the coupling effect of water hammer and thermal shock caused by the valve switching action of LNG flexible pipeline, is suitable for low temperature working conditions, and can collect multi-dimensional test data. It provides reliable test support for the material selection, structural optimization and safety assessment of LNG flexible pipeline, and has strong practicality and promotion value. Attached Figure Description

[0024] Figure 1 This is a schematic diagram showing the connection of the valve assembly, the medium circulation and temperature control components, and the flexible test carrier in this utility model;

[0025] Figure 2 This is a connection diagram of the low-temperature detection component and the control and acquisition component in this utility model.

[0026] Attached diagram labels: A - First pipeline; B - Second pipeline; C - Third pipeline; D - Fourth pipeline;

[0027] YB1 - First low-temperature pressure gauge; YB2 - Second low-temperature pressure gauge; YB3 - Third low-temperature pressure gauge; YB4 - Fourth low-temperature pressure gauge; YB5 - Fifth low-temperature pressure gauge; YB6 - Sixth low-temperature pressure gauge;

[0028] LL1 - First cryogenic flow meter; LL2 - Second cryogenic flow meter;

[0029] W1 - First temperature sensor; W2 - Second temperature sensor; W3 - Third temperature sensor; W4 - Fourth temperature sensor;

[0030] F1 - First shut-off valve; F2 - Second shut-off valve; F3 - Third shut-off valve; F4 - Fourth shut-off valve; F5 - Electric on / off valve; F6 - Pneumatic regulating valve; F7 - Pressure relief valve; F8 - Safety valve; F9 - Vent valve; F10 - Drain valve;

[0031] C01-LNG storage tank; B01-Cryogenic pump; ZL01-Refrigeration unit; JR01-Heating module; G01-Constant temperature buffer tank; GDD01-Flexible test pipeline;

[0032] K1 - Control box; SS1 - Display and storage module; CJ01 - Data acquisition module. Detailed Implementation

[0033] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of this utility model is not limited to the following embodiments, and any modifications and / or alterations made to this utility model will fall within the protection scope of this utility model.

[0034] like Figure 1 , 2 As shown, this utility model discloses a technical solution: a test system for simulating the coupling effect of water hammer and thermal shock in the switching valve of an LNG flexible pipeline. The system includes a cryogenic detection component, a valve assembly, a medium circulation and temperature control component, a control and acquisition component, and a flexible test carrier. The cryogenic detection component is used to collect real-time pressure, flow, and temperature data within the pipeline. The valve assembly is used for pipeline on / off control, flow regulation, and pressure protection. The medium circulation and temperature control component provides a stable cryogenic LNG medium and achieves circulation and temperature gradient regulation. The control and acquisition component controls the operation of each component and processes data. The flexible test pipeline GDD01 serves as the test carrier to bear the coupling effect.

[0035] The LNG storage tank C01 is equipped with a vent valve F9 at the top and a drain valve F10 at the bottom. Vent valve F9 releases volatile gases from the tank to prevent pressure buildup, while drain valve F10 is used for tank cleaning and residual liquid discharge, ensuring convenient equipment maintenance. LNG storage tank C01 has a volume of 500L, is made of stainless steel, and has a pressure resistance of 2.0MPa. It can be wrapped with a 50mm thick polyurethane insulation layer. LNG storage tank C01 is connected to the refrigeration unit ZL01, which is a liquid nitrogen-assisted refrigeration unit with a cooling capacity of 5kW and a temperature control accuracy of ±1℃. It is used to maintain the LNG medium temperature inside the tank at a stable -162℃±5℃, suitable for cryogenic LNG conditions. A fourth shut-off valve F4 and a fifth cryogenic pressure gauge YB5 are connected in series between the refrigeration unit ZL01 and the LNG storage tank. On the connecting pipeline of storage tank C01, the fourth shut-off valve F4 is used to control the on / off of the refrigeration branch, which facilitates the separate maintenance of the refrigeration unit. The fifth low-temperature pressure gauge YB5 is used to monitor the medium pressure of the refrigeration branch and provide real-time feedback on the pressure status at the output end of the refrigeration unit. Together with F4, it realizes pressure monitoring during the maintenance of the refrigeration branch and avoids the low-temperature control effect being affected by abnormal pressure.

[0036] LNG storage tank C01 is connected to the input end of cryogenic pump B01 through the first pipeline A. The first pipeline A is sequentially equipped with a first shut-off valve F1, a first cryogenic pressure gauge YB1, and a first temperature sensor W1. The first shut-off valve F1 is used to isolate LNG storage tank C01 from cryogenic pump B01, which facilitates equipment maintenance. The first cryogenic pressure gauge YB1 is used to monitor the pressure at the output end of the storage tank, and the first temperature sensor W1 collects the temperature of the medium at the tank outlet in real time. The output of cryogenic pump B01 is connected to constant temperature buffer tank G01 via a second pipeline B. The second pipeline B is sequentially equipped with a second shut-off valve F2, a first cryogenic flow meter LL1, a second cryogenic pressure gauge YB2, and a second temperature sensor W2. Cryogenic pump B01 is a cryogenic explosion-proof centrifugal pump, model ISW-50-160, with a head of 0-50m, a flow rate of 0-50m³ / h, and a temperature resistance of -196℃ to 80℃, providing power for media circulation. The first cryogenic flow meter LL1 monitors the pump outlet flow, the second cryogenic pressure gauge YB2 monitors the pump outlet pressure, and the second temperature sensor W2 collects the temperature of the medium before it enters the buffer tank. The constant temperature buffer tank G01 has a built-in heating module JR01, used to fine-tune the medium temperature to create a temperature gradient and simulate thermal shock. The outer wall of the tank is also equipped with an insulation layer to reduce temperature loss. The constant temperature buffer tank G01 has a volume of 200L, is made of stainless steel, and has a pressure resistance of 2.0MPa.

[0037] The constant temperature buffer tank G01 is connected to one end of the flexible test pipeline GDD01 via the third pipeline C. An electric switch valve F5 is installed on the third pipeline C, and a third cryogenic pressure gauge YB3 and a third temperature sensor W3 are respectively arranged on both sides of the electric switch valve F5. The other end of the flexible test pipeline GDD01 is connected to the LNG storage tank C01 via the fourth pipeline D, forming a closed loop. A second cryogenic flow meter LL2, a third shut-off valve F3, a fourth cryogenic pressure gauge YB4, and a fourth temperature sensor W4 are installed sequentially on the fourth pipeline D. The third cryogenic pressure gauge YB3 and the fourth cryogenic pressure gauge YB4 monitor the pressure changes on both sides of the electric switch valve F5, capturing the pressure fluctuations during water hammer impact. The third temperature sensor W3 and the fourth temperature sensor W4 collect the medium temperature on both sides of the switch valve and record the temperature change pattern under thermal shock. The second cryogenic flow meter LL2 is used to monitor the return flow rate, and works with the first cryogenic flow meter LL1 to achieve balanced monitoring of the circulating flow rate.

[0038] Pneumatic regulating valve F6 is connected in parallel across electric switching valve F5 to regulate pipeline flow and pressure balance, preventing excessive flow fluctuations when the switching valve operates. Pressure relief valve F7 is connected at one end to the third pipeline C (located between thermostatic buffer tank G01 and electric switching valve F5), and at the other end to the exhaust gas recovery branch to release overpressure caused by water hammer impact, protecting pipeline and equipment safety. Safety valve F8 is installed at the top of thermostatic buffer tank G01, with an opening pressure set at 1.2 MPa to prevent safety accidents caused by excessive pressure inside the tank. The sixth low-temperature pressure gauge YB6 is installed at the reserved interface at the bottom or side of thermostatic buffer tank G01 to monitor the bottom pressure of the medium inside the tank.

[0039] The data acquisition module CJ01 is electrically connected to the first to sixth cryogenic pressure gauges YB1-YB6, the first to second cryogenic flow meters LL1-LL2, and the first to fourth temperature sensors W1-W4, respectively. It is an NI cDAQ-9178 model and equipped with a data acquisition card. The sampling frequency is adjustable from 0-100Hz. It is used to acquire pressure, flow, and temperature data in real time. The data acquisition module CJ01 is connected to the display and storage module SS1 via RS485 communication to realize real-time data display, local storage, and USB export, which facilitates subsequent data analysis. The display and storage module SS1 is an industrial panel PC with built-in data storage software, supporting real-time data display, local storage (1TB storage capacity), and USB export (Excel format).

[0040] The control box K1 is electrically connected to the cryogenic pump B01, the refrigeration unit ZL01, the heating module JR01, the electric switching valve F5, and the pneumatic regulating valve F6. It adopts a PLC controller (model S7-1200) and is equipped with a 7-inch touch screen operation interface, which can realize the start and stop control of each component, parameter setting (switching valve speed, temperature, flow) and status display, making the operation convenient and intuitive.

[0041] Specifically, the flexible test pipeline GDD01 uses a special flexible hose for LNG, with an inner diameter of 50-100mm, a pressure resistance of 2.0MPa, and a temperature range of -196℃ to 60℃. The hose is connected by quick connectors at both ends, which facilitates the replacement of samples of different specifications and materials, and improves the versatility of the test.

[0042] The heating module JR01 is a low-temperature resistant electric heating tube with adjustable power from 0 to 5kW. When used with the refrigeration unit ZL01, it can achieve temperature gradient adjustment within the range of -162℃ to -120℃, with a temperature control accuracy of ±1℃, and can accurately simulate different degrees of thermal shock effects.

[0043] The electric on / off valve F5 is a low-temperature explosion-proof type with an adjustable switching time of 0.1-5s, used to simulate the water hammer effect under different switching speeds; the first to sixth low-temperature pressure gauges YB1-YB6 are shock-resistant low-temperature pressure gauges, model YTN-100, with a measuring range of 0-2.5MPa, an accuracy of 0.4 grade, and a temperature resistance of -196℃ to 80℃. They are shock-resistant and can adapt to pipeline vibration conditions; the first to second low-temperature flow meters LL1-LL2 are Coriolis mass flow meters with a measuring range of 0-50m³ / h, an accuracy of ±0.2%, and a temperature resistance of -196℃ to 100℃; the first to fourth temperature sensors W1-W4 are PT100 platinum resistance thermometers with a measuring range of -200℃ to 100℃, an accuracy of ±0.1℃, and a threaded installation method to ensure stable temperature measurement.

[0044] Pipelines A, B, C, and D all use 304 stainless steel cryogenic tubing with an outer diameter of 80mm and a wall thickness of 5mm. They are resistant to temperatures ranging from -196℃ to 100℃. All joints on the pipelines are cryogenic welded joints or quick-connect joints, and the sealing material is polytetrafluoroethylene (PTFE) to ensure cryogenic sealing performance and prevent LNG leakage and cold energy loss. The outside of the pipelines is wrapped with a 30mm thick rock wool insulation layer to reduce cold energy loss and reduce the impact of ambient temperature on the test.

[0045] In the valve assembly, the first to fourth shut-off valves F1-F4 and the pneumatic regulating valve F6 are all cryogenic stainless steel valves, with a temperature resistance of -196℃ to 100℃ and a pressure resistance of 2.5MPa; the electric switching valve F5 is an explosion-proof cryogenic electric valve, model Q941F-25P, with a steplessly adjustable switching time of 0.1-5s, suitable for LNG media; the pressure relief valve F7 is a pilot-operated cryogenic pressure relief valve with a set opening pressure of 0.8MPa; the safety valve F8 is a spring-loaded cryogenic safety valve with an opening pressure of 1.2MPa; the vent valve F9 and the drain valve F10 are cryogenic ball valves, which are easy to operate and seal.

[0046] During the experiment, the medium was first added and the cryogenic temperature was maintained. The circulation system was then started until it reached a stable state. Test parameters (valve switching speed, temperature gradient, flow rate) were set via control box K1. The data acquisition module CJ01 was activated, controlling the electric switching valve F5 to simultaneously collect pressure, temperature, and flow rate data. Through multiple sets of variable tests, the changing patterns of the coupling effect between water hammer and thermal shock were analyzed. During the experiment, the pressure relief valve F7 and the safety valve F8 provided dual protection, effectively avoiding the risk of overpressure and ensuring experimental safety.

[0047] The initial state of this invention is that all valves are closed, an appropriate amount of LNG is added to the LNG storage tank, and the refrigeration unit is started to maintain the low temperature. Then, the following coupling effects can be studied:

[0048] (1) Test on the coupling effect of water hammer and thermal shock at different valve switching speeds

[0049] Preparation: Open the vent valve F9 and inject an appropriate amount of LNG into the LNG storage tank C01. Start the refrigeration unit ZL01 and stabilize the medium temperature at -162℃. Open the first shut-off valve F1, the second shut-off valve F2, and the third shut-off valve F3. Close the drain valve F10 and the pressure relief valve F7. Start the cryogenic pump B01 and adjust the flow rate to the set value (e.g., 20 m³ / h). Run the pump until the pipeline medium circulation is stable.

[0050] Action process:

[0051] 1. Set the opening and closing time of the electric switch valve F5 (e.g., 0.5s, 1s, 2s) through the control box K1.

[0052] 2. Start the data acquisition module CJ01, set the sampling frequency to 50Hz, and begin collecting pressure, temperature, and flow data;

[0053] 3. Control the electric switch valve F5 to close quickly via control box K1, and at the same time record the pressure change on both sides of the switch valve (third low temperature pressure gauge YB3, fourth low temperature pressure gauge YB4) and the temperature change (third temperature sensor W3, fourth temperature sensor W4).

[0054] 4. After the pipeline pressure and temperature stabilize, open the electric switch valve F5 to maintain the circulation state;

[0055] 5. Adjust the switching time of the electric switching valve F5, repeat steps 2-4, collect multiple sets of data, and analyze the variation law of coupling effect under different switching speeds.

[0056] (2) Test on the coupling effect of water hammer and thermal shock under different temperature gradients

[0057] Preparation: Open the vent valve F9 and inject an appropriate amount of LNG into the LNG storage tank C01. Start the refrigeration unit ZL01 and stabilize the medium temperature at -162℃. Open the first shut-off valve F1, the second shut-off valve F2, and the third shut-off valve F3, and close the drain valve F10 and the pressure relief valve F7. Start the cryogenic pump B01, adjust the flow rate to the set value, and run it until the circulation is stable. Fine-tune the medium temperature in the constant temperature buffer tank G01 through the heating module JR01 to form a set temperature gradient (such as -162℃ to -140℃, -162℃ to -130℃).

[0058] Action process:

[0059] 1. Set the opening and closing time of the electric switch valve F5 to a fixed value (e.g., 1 second), and start the data acquisition module CJ01;

[0060] 2. Control the electric switch valve F5 to close quickly and record the parameter changes under the coupling of water hammer impact pressure and temperature gradient;

[0061] 3. After the pipeline stabilizes, adjust the heating module JR01 to change the temperature gradient, and repeat steps 1-2.

[0062] 4. Collect multiple sets of experimental data under different temperature gradients and analyze the effect of temperature changes on the coupling effect.

[0063] (3) Test on the coupling effect of water hammer and thermal shock under different medium flow rates

[0064] Preparation: Same as (1) preparation, maintain the medium temperature at -162℃, and fix the switching time of electric switch valve F5 to 1s.

[0065] Action process:

[0066] 1. Adjust the pipeline circulation flow rate (e.g., 15 m³ / h, 20 m³ / h, 25 m³ / h) using cryogenic pump B01, and start data acquisition module CJ01;

[0067] 2. Control the electric switch valve F5 to close quickly, and record the water hammer pressure and thermal shock coupling parameters at the corresponding flow rate;

[0068] 3. After the pipeline stabilizes, adjust the flow rate to the next set value and repeat steps 1-2;

[0069] 4. Compare and analyze the differences in coupling effects under different flow rates to provide a basis for pipeline flow control.

[0070] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A test system for simulating the coupling effect of water hammer and thermal shock in a flexible LNG pipeline switching valve, characterized in that: This includes low-temperature detection components, valve assemblies, media circulation and temperature control components, control and data acquisition components, and flexible test carriers; The low-temperature detection component is used to collect pressure, flow rate and temperature data in the pipeline in real time, including a first low-temperature pressure gauge (YB1), a second low-temperature pressure gauge (YB2), a third low-temperature pressure gauge (YB3), a fourth low-temperature pressure gauge (YB4), a fifth low-temperature pressure gauge (YB5), a sixth low-temperature pressure gauge (YB6), a first low-temperature flow meter (LL1), a second low-temperature flow meter (LL2), a first temperature sensor (W1), a second temperature sensor (W2), a third temperature sensor (W3) and a fourth temperature sensor (W4). The valve assembly is used for pipeline on / off, flow regulation and pressure protection, including a first shut-off valve (F1), a second shut-off valve (F2), a third shut-off valve (F3), a fourth shut-off valve (F4), an electric switching valve (F5), a pneumatic regulating valve (F6), a pressure relief valve (F7), a safety valve (F8), a venting valve (F9) and a drain valve (F10). The medium circulation and temperature control components are used to provide a stable cryogenic LNG medium and realize circulation and temperature gradient regulation, including an LNG storage tank (C01), a cryogenic pump (B01), a refrigeration unit (ZL01), a heating module (JR01), and a constant temperature buffer tank (G01). The control and acquisition component is used to control the operation of each component and data processing, including the control box (K1), the display and storage module (SS1), and the data acquisition module (CJ01). The flexible test carrier is used to bear the coupling effect test of water hammer and thermal shock, and is a flexible test pipeline (GDD01).

2. The test system for simulating the coupling effect of water hammer and thermal shock in a flexible LNG pipeline switching valve according to claim 1, characterized in that: The LNG storage tank (C01) is equipped with a vent valve (F9) at the top and a drain valve (F10) at the bottom, and is connected to the refrigeration unit (ZL01); The LNG storage tank (C01) is connected to the input end of the cryogenic pump (B01) via a first pipeline (A). A first shut-off valve (F1), a first cryogenic pressure gauge (YB1), and a first temperature sensor (W1) are installed sequentially on the first pipeline (A). The output end of the cryogenic pump (B01) is connected to the constant temperature buffer tank (G01) via a second pipeline (B). A second shut-off valve (F2), a first cryogenic flow meter (LL1), a second cryogenic pressure gauge (YB2), and a second temperature sensor (W2) are installed sequentially on the second pipeline (B). The constant temperature buffer tank (G01) has a built-in heating module (JR01); the constant temperature buffer tank (G01) is connected to one end of the flexible test pipeline (GDD01) through the third pipeline (C), and an electric switch valve (F5) is installed on the third pipeline (C), with a third low temperature pressure gauge (YB3) and a third temperature sensor (W3) respectively on both sides; the other end of the flexible test pipeline (GDD01) is connected to the LNG storage tank (C01) through the fourth pipeline (D) to form a closed loop circulation, and a second low temperature flow meter (LL2), a third shut-off valve (F3), a fourth low temperature pressure gauge (YB4), and a fourth temperature sensor (W4) are installed sequentially on the fourth pipeline (D).

3. The test system for simulating the coupling effect of water hammer and thermal shock in a flexible LNG pipeline switching valve according to claim 2, characterized in that: The pneumatic regulating valve (F6) is connected in parallel across the electric switching valve (F5); one end of the pressure relief valve (F7) is connected to the third pipeline (C), and the other end is connected to the exhaust gas recovery branch, used to release the overpressure generated by water hammer impact; the safety valve (F8) is installed on the top of the constant temperature buffer tank (G01) to prevent the pressure inside the tank from being too high.

4. The test system for simulating the coupling effect of water hammer and thermal shock in a flexible LNG pipeline switching valve according to claim 2, characterized in that: The data acquisition module (CJ01) is electrically connected to the first low-temperature pressure gauge (YB1), the second low-temperature pressure gauge (YB2), the third low-temperature pressure gauge (YB3), the fourth low-temperature pressure gauge (YB4), the fifth low-temperature pressure gauge (YB5), the sixth low-temperature pressure gauge (YB6), the first low-temperature flow meter (LL1), the second low-temperature flow meter (LL2), the first temperature sensor (W1), the second temperature sensor (W2), the third temperature sensor (W3), and the fourth temperature sensor (W4) respectively, for real-time acquisition of pressure, flow rate, and temperature data. The data acquisition module (CJ01) is also communicatively connected to the display and storage module (SS1) to realize the display, storage, and export of data. The control box (K1) is electrically connected to the cryogenic pump (B01), refrigeration unit (ZL01), heating module (JR01), electric switching valve (F5), and pneumatic regulating valve (F6), and is used to control the start and stop of each component, parameter adjustment, and the operating speed control of the switching valve.

5. The test system for simulating the coupling effect of water hammer and thermal shock in a flexible LNG pipeline switching valve according to claim 1, characterized in that: The flexible test pipeline (GDD01) is an LNG-specific flexible hose with an inner diameter of 50-100mm, a pressure resistance of 2.0MPa, and a temperature range of -196℃ to 60℃.

6. The test system for simulating the coupling effect of water hammer and thermal shock in a flexible LNG pipeline switching valve according to claim 1, characterized in that: The heating module (JR01) is a low-temperature resistant electric heating tube with an adjustable power of 0-5kW. When used in conjunction with the refrigeration unit (ZL01), it can achieve temperature gradient adjustment within the range of -162℃ to -120℃, with a temperature control accuracy of ±1℃.

7. The test system for simulating the coupling effect of water hammer and thermal shock in a flexible LNG pipeline switching valve according to claim 1, characterized in that: The electric switching valve (F5) is a low-temperature explosion-proof type with an adjustable switching time of 0.1-5s, used to simulate the water hammer effect at different switching speeds. The first low-temperature pressure gauge (YB1), the second low-temperature pressure gauge (YB2), the third low-temperature pressure gauge (YB3), the fourth low-temperature pressure gauge (YB4), the fifth low-temperature pressure gauge (YB5), and the sixth low-temperature pressure gauge (YB6) are all shock-resistant low-temperature pressure gauges with a measurement range of 0-2.5MPa and an accuracy of 0.4 grade. The first temperature sensor (W1), the second temperature sensor (W2), the third temperature sensor (W3), and the fourth temperature sensor (W4) all use PT100 platinum resistance thermometers with a measurement accuracy of ±0.1℃.

Images