An experimental device and method for lead-bismuth flow-induced vibration

Abstract

The present invention provides a lead-bismuth flow-induced vibration experimental device and method. The main loop of the experimental device of the present invention is inclined at an appropriate angle with the horizontal line as a whole except for the experimental section, so as to fully recover the liquid lead-bismuth alloy. The experimental loop uses a buffer tank for vibration isolation. The flange is connected to the shell of the experimental section through a flange, which is convenient for the replacement of different rod bundle structures. Moreover, the fiber optic strain gauge and the acceleration sensor can measure strain and acceleration simultaneously, and can realize the measurement of low-frequency strain and high-frequency strain. The lead-bismuth liquid storage system includes three identical subsystems, and the heat-conducting oil in the heat-conducting oil tank in the heating subsystem is used to uniformly heat the lead-bismuth liquid storage tank, and then the lead-bismuth in the lead-bismuth liquid storage tank is melted and the temperature of the lead-bismuth is controlled.

Description

Technical Field

[0001] The present invention belongs to the technical field of research on the mechanism of flow-induced vibration experiments in special liquid-phase media, and particularly relates to a lead-bismuth flow-induced vibration experiment device and method. Background Art

[0002] Lead-cooled fast reactors have become one of the six most promising reactor types of the fourth generation internationally due to their high efficiency, compact structure, and breedability. The literature ("Research on the Thermal-Hydraulic Model of a Helical Tube Once-Through Steam Generator in a Lead-Bismuth Fast Reactor", Proceedings of the 16th National Conference on Reactor Thermal-Hydraulics and the 2019 Academic Annual Conference of the Key Laboratory of Nuclear Reactor Thermal-Hydraulics Technology of CNNC) points out that the steam generators of lead-bismuth reactors generally use helical tube steam generators, which can be regarded as the flow of lead-bismuth across tube bundles. Historically, flow-induced vibration has caused accidents such as wear and rupture of steam generators in other reactor types such as pressurized water reactors, seriously reducing the safety and economy of the reactors. In addition, there will also be flow-induced fuel rod vibration phenomena in the axial flow of the reactor core, causing fretting wear of the reactor core fuel rods and reducing the life of the fuel rods. Although there are many studies on flow-induced vibration in water media, there are huge differences between lead-bismuth fluids and water fluids, and the relevant mechanisms and theoretical models are not the same. Therefore, it is necessary to study the mechanism of lead-bismuth flow-induced vibration to ensure the safety and reliability of materials such as steam generators and fuel rods designed.

[0003] Existing lead-bismuth alloy loops at home and abroad focus on the research of natural circulation ability (CN103413579A), oxygen control and corrosion (CN208847634U, CN103914088A), and bubble pump circulation ability (CN106837769A), while experimental research on lead-bismuth flow-induced vibration is still relatively lacking.

[0004] The patent "CN103592094 A A Flow-Induced Tube Bundle Vibration Experiment Device" is only applicable to water media. Compared with water media, lead-bismuth alloy has the characteristics of high temperature, strong corrosiveness, volatile toxic gases, and high Reynolds number. Its flow-induced vibration experiment needs to effectively overcome these difficulties, and the current water or air flow-induced vibration experiment system is not applicable to it. Summary of the Invention

[0005] The purpose of the present invention is to provide a lead-bismuth flow-induced vibration experiment device and method to overcome the problems that the existing flow-induced vibration experiment system is not applicable or does not meet the research requirements of lead-bismuth flow-induced vibration.

[0006] A lead-bismuth flow-induced vibration experimental device, comprising a lead-bismuth flow-induced vibration device, a lead-bismuth liquid storage device, a vacuum device and an argon device; the lead-bismuth flow-induced vibration device includes a lead-bismuth pump, a vibration isolation hose R1, an expansion tank, a buffer tank, an experimental section, a vibration isolation hose R2 and a heat exchanger. The lead-bismuth pump is connected to the expansion tank through the vibration isolation hose R1. A water pump is connected between the lead-bismuth pump and the expansion tank, and a valve A1 is arranged in front of the water pump; the expansion tank is connected to the buffer tank, the buffer tank is connected to the inlet of the experimental section, one end of the outlet of the experimental section is connected to the heat exchanger, and the other end of the outlet of the experimental section is connected to the bottom of the lead-bismuth liquid storage device; the top of the lead-bismuth liquid storage device is respectively connected to the vacuum device and the argon device, the top of the lead-bismuth liquid storage device is also connected to the top of the expansion tank, and the vacuum device and the argon device are respectively connected to the top of the expansion tank.

[0007] Further, a large valve A2 and a temperature sensor T2 are arranged between the expansion tank and the buffer tank. A pipeline connected to the pipeline connecting the expansion tank and the buffer tank is connected, and a valve A3 and a temperature sensor T3 are installed; a temperature sensor T1 and a pressure sensor P1 are arranged on the expansion tank.

[0008] Further, a pressure sensor P2 and a temperature sensor T4 are arranged between the buffer tank and the experimental section.

[0009] Further, a valve A4 and a temperature sensor T7 are installed between the experimental section and the heat exchanger, a temperature sensor T5 is installed on the experimental section, a pressure sensor P3 and a temperature sensor T6 are installed at the connection section of the lower end of the experimental section and the pipeline, and a valve A5 is installed between the experimental section and the lead-bismuth liquid storage device.

[0010] Further, the lead-bismuth liquid storage device includes three identical subsystems. Each subsystem includes a lead-bismuth liquid storage tank, heat-conducting oil and a heat-conducting oil tank. The heat-conducting oil is in the heat-conducting oil tank, and the heat-conducting oil tank is installed in the lead-bismuth liquid storage tank. Each subsystem is provided with a valve.

[0011] Further, a valve A8 and a valve A7 are arranged on the pipeline connecting the top of the lead-bismuth liquid storage device and the top of the expansion tank.

[0012] Further, the vacuum device includes a vacuum pump, and a valve A15 is arranged in front of the vacuum pump.

[0013] Further, the argon device consists of 8 bottles of argon and a main pipe. The argon is connected to the main pipe, and the main pipe is connected to the pipeline between the valve A8 and the valve A7, and a valve A14 is arranged.

[0014] Further, a valve A10 and a vacuum gauge P4 are provided on the pipeline connecting the top of the lead-bismuth liquid storage device to the vacuum device, and a valve A9 and a vacuum gauge P5 are provided on the pipeline connecting the top of the bismuth liquid storage device to the argon device. The pipeline of the vacuum device is connected between valve A9 and valve A10.

[0015] A lead-bismuth flow-induced vibration experimental method includes the following steps:

[0016] Step 1: Conduct a water flow-induced vibration experiment;

[0017] Close all valves of the experimental system; open large valve A2, valve A1, valve A4, valve A9, valve A15, and the vacuum pump; then use a water pump to inject water into the experimental loop, and observe whether the reading of pressure sensor P1 changes during this period; when the reading of P1 changes, turn off the water pump, then close valve A1 to stop water injection; then sequentially close valve A15, valve A9, and the vacuum pump; turn on the lead-bismuth pump and obtain the required flow rate by adjusting large valve A2; then conduct steady-state debugging, and during this period, take away the excess heat generated by the water driven by the lead-bismuth pump through the heat exchanger to maintain the water in the experiment at the required temperature; after the loop operates stably for two minutes, conduct real-time acquisition of experimental data. Pressure sensor P2 and pressure sensor P3 respectively measure the inlet and outlet pressures of the experimental section, and temperature sensors T4, T5, and T6 respectively measure the inlet temperature of the experimental section, the temperature of the experimental section, and the outlet temperature of the experimental section; after the experiment is completed, turn off the lead-bismuth pump; then open valve A6 to drain the water in the loop; after the water in the loop is drained, close all valves and cut off the power supply, and the water flow-induced vibration experiment ends;

[0018] Step 2: Conduct a lead-bismuth flow-induced vibration experiment;

[0019] Turn on the tracing heating outside the pipeline through which lead-bismuth will flow in the experimental system, preheat the pipeline to 200 °C, and at the same time heat and melt the lead-bismuth in the lead-bismuth storage tank and heat it to the required temperature; Open the small valve A3, valve A4, valve A9, valve A15, and turn on the vacuum pump to remove the air in the loop; Then open valve A11, valve A12, valve A13, and valve A5; Turn on the argon device, open valve A14, gradually open and adjust valve A8, pressurize the gas space above the liquid lead-bismuth in the lead-bismuth storage tank, and gradually press the lead-bismuth into the experimental loop. During this period, observe whether the reading of the pressure sensor P1 changes; When the reading of the pressure sensor P1 changes, that is, when the liquid level reaches P1, stop pressurizing the argon device and close valve A5, valve A8, and valve A14; Then open valve A10. Keep the vacuum device on during the experiment and keep the inside of the storage tank under negative pressure; Then turn on the lead-bismuth pump and adjust the small valve A2 to obtain the required lead-bismuth flow rate; Then turn off the tracing heating, and the lead-bismuth in the lead-bismuth storage tank should always remain in the liquid phase; Then conduct steady-state debugging. During this period, adjust the heat exchanger to remove the excess heat generated by the lead-bismuth pump driving the lead-bismuth and maintain the lead-bismuth in the experiment at the required temperature; After the loop operates steadily for two minutes, conduct real-time acquisition of experimental data. The pressure sensor P2 and the pressure sensor P3 measure the inlet and outlet pressures of the experimental section respectively, and the temperature sensors T4, T5, and T6 measure the inlet temperature of the experimental section, the temperature of the experimental section, and the outlet temperature of the experimental section respectively; During the whole experiment, monitor whether the local temperature is lower than the lead-bismuth solidification temperature through each temperature sensor in the experimental loop; After the experiment is completed, close the secondary loop of the heat exchanger, turn on the tracing heating, and at the same time turn off the lead-bismuth pump; Then close valve A9 and open valve A5; Then turn on the argon device, open valve A14, gradually open and adjust valve A7, pressurize the top of the expansion tank of the experimental loop, and press the lead-bismuth back into the expansion tank. During this period, calculate the lead-bismuth liquid level from the pressures measured by the pressure sensors at the top and bottom of the lead-bismuth storage tank 10 to determine the recovery amount of lead-bismuth. After the lead-bismuth is completely recovered, turn off the argon device, valve A14, valve A7, and valve A5 in sequence, and then turn off valve A15, vacuum pump 7, and valve A10 in sequence, and cut off the power supply to end the experiment.

[0020] The beneficial effects of the present invention are as follows:

[0021] The main loop of this experimental device is inclined at an appropriate angle with the horizontal line as a whole except for the experimental section to fully recover the liquid lead-bismuth alloy, and the experimental loop uses a buffer box for vibration isolation.

[0022] The experimental section includes a flange and a rod / tube bundle welded to the flange, an optical fiber strain gauge, an acceleration sensor, a thermometer and an experimental section housing installed in the rod / tube bundle. The flange is connected to the experimental section housing through a flange, which facilitates the replacement of different rod bundle structures. The optical fiber strain gauge and the acceleration sensor can measure strain and acceleration simultaneously, and can realize the measurement of low-frequency strain and high-frequency strain.

[0023] The heat exchanger exports the heat generated by the lead-bismuth centrifugal pump doing work on the lead-bismuth medium to control the temperature of the lead-bismuth in the loop. A safety valve is installed on the heat exchanger to prevent overpressure caused by the flashing of the cooling water in the heat exchanger.

[0024] The lead-bismuth liquid storage system includes three identical subsystems. By heating the heat-conducting oil in the heat-conducting oil tank in the subsystem, the lead-bismuth liquid storage tank can be uniformly heated, and then the lead-bismuth in the lead-bismuth liquid storage tank can be melted and the temperature of the lead-bismuth can be controlled.

[0025] There are thermocouple penetration ports at the top of the lead-bismuth liquid storage tank of the subsystem, which are respectively used to measure the temperature of the lead-bismuth alloy at different heights in the tank. The liquid level height of the lead-bismuth in the lead-bismuth liquid storage tank can be obtained by converting the pressures measured by two pressure sensors at the bottom and one pressure sensor at the top of the lead-bismuth liquid storage tank of the subsystem.

[0026] The three subsystems include one redundant subsystem. The three subsystems are filled with lead-bismuth with a capacity not exceeding two lead-bismuth liquid storage tanks. When the pressure sensors and temperature sensors of one of the subsystems fail, the lead-bismuth is transferred to the other two subsystems to replace the failed pressure sensors and temperature sensors. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of a lead-bismuth flow-induced vibration experimental system of the present invention. Detailed Embodiments

[0028] The present invention will be further described below with reference to the drawings.

[0029] As Figure 1 shown, 1 is a water pump, 2 is a lead-bismuth pump, 3 is an expansion tank, 4 is a buffer tank, 5 is an experimental section, 6 is a heat exchanger, 7 is a vacuum pump, 8 is an argon gas tank, 9 is a main pipe, 10 is a lead-bismuth liquid storage tank, 11 is heat-conducting oil, 12 is a heat-conducting oil tank, A2 is a large valve, A3 is a small valve, A1, A4, A5, A6, A7, A8, A9, A11, A12, A13, A14, A15 are valves, T1, T2, T3, T4, T5, T6, T7 are temperature sensors, P1, P2, P3 are pressure sensors, and P4, P5 are vacuum gauges.

[0030] The present invention relates to an experimental device and method for lead-bismuth flow-induced vibration. The system consists of a lead-bismuth pump 2, a vibration isolation hose R1, an expansion tank 3, a buffer tank 4, an experimental section 5, a vibration isolation hose R2, and a heat exchanger 6, which are connected in sequence to form the main loop of the experimental system. Among them, a branch is separated between the outlet of the experimental section 5 and the vibration isolation hose R2 and connected to the bottom of the lead-bismuth liquid storage system. The top of the lead-bismuth liquid storage device is respectively connected to a vacuum device and an argon device. The vacuum device and the argon device are respectively connected to the top of the expansion tank 3. A branch is separated between R1 and the lead-bismuth pump 2 and connected to a water pump 1. All connections are pipe connections.

[0031] Among them, the lead-bismuth liquid storage device, the vacuum device, and the argon device serve as auxiliary systems. The lead-bismuth liquid storage device consists of three identical subsystems. Each subsystem is composed of a lead-bismuth storage tank 10, heat-conducting oil 11, and a heat-conducting oil tank 12; the vacuum device consists of a vacuum pump 7, vacuum gauges P4, P5, and valves A9, A10, A15; the argon device consists of 8 bottles of argon plus a main pipe 9, and valves A7, A8, A14.

[0032] The main loop of the experimental system, except for the experimental section, is inclined at an appropriate angle to the horizontal line to fully recover the liquid lead-bismuth alloy.

[0033] Vibration isolation is achieved through the buffer tank 4.

[0034] The experimental section 5 includes a flange and a rod / tube bundle welded to the flange, an optical fiber strain gauge, an acceleration sensor, a thermometer, and an experimental section housing installed in the rod / tube bundle. Among them, the flange is connected to the experimental section housing through a flange, which is convenient for replacing different rod bundle structures. And the optical fiber strain gauge and the acceleration sensor can measure strain and acceleration simultaneously, and can realize the measurement of low-frequency strain and high-frequency strain.

[0035] The heat exchanger 6 exports the heat generated by the work done by the lead-bismuth centrifugal pump on the lead-bismuth medium to achieve temperature control of the lead-bismuth in the loop. A safety valve is installed on the heat exchanger 6 to prevent overpressure caused by the flashing of the cooling water in the heat exchanger.

[0036] The lead-bismuth liquid storage system includes three identical subsystems. By heating the heat-conducting oil 11 in the heat-conducting oil tank 12 in the subsystem, the lead-bismuth storage tank 10 can be uniformly heated, and then the lead-bismuth in the lead-bismuth storage tank 10 can be melted and the temperature of the lead-bismuth can be controlled.

[0037] Two thermocouple penetration ports are opened at the top of the subsystem lead-bismuth storage tank 10, which are respectively used to measure the temperature of the lead-bismuth alloy at different heights in the tank. And the liquid level height of the lead-bismuth in the lead-bismuth storage tank 10 is obtained by converting the pressures measured by two pressure sensors at the bottom and one pressure sensor at the top of the subsystem. Among them, the two pressure sensors at the bottom are redundantly designed.

[0038] The three subsystems include a redundant subsystem. The three subsystems are filled with no more than two lead-bismuth storage tanks 10 in capacity of lead-bismuth. When the pressure sensors and temperature sensors of one of the subsystems fail, the lead-bismuth is transferred to the other two subsystems to replace the failed pressure sensors and temperature sensors.

[0039] The vacuum device is used in the experiment to remove the gas in the experimental loop, so as to achieve deoxidation of the loop and thus avoid the reaction between lead-bismuth and oxygen, and to form a negative pressure in the upper space of the lead-bismuth storage tank 10 during the experiment so that the lead-bismuth can flow back to the lead-bismuth storage tank 10 in case of an accident.

[0040] The argon device presses the lead-bismuth into the experimental loop before the experiment and presses the lead-bismuth back into the lead-bismuth storage tank 10 after the experiment.

[0041] First, conduct the water flow-induced vibration experiment, and control the flow rate with the large valve A2; after the water flow-induced vibration experiment is completed, then conduct the lead-bismuth flow-induced vibration experiment, and control the flow rate with the small valve A3. To respectively achieve the flow-induced vibration experiments with water medium and lead-bismuth medium.

[0042] The experimental method of an experimental system for lead-bismuth flow-induced vibration of the present invention is as follows:

[0043] The experimental system for lead-bismuth flow-induced vibration first conducts the water flow-induced vibration experiment and then conducts the lead-bismuth flow-induced vibration experiment.

[0044] Conduct the water flow-induced vibration experiment: First, close all the valves of the experimental system; then open the large valve A2, valves A1, A4, A9, A15; turn on the vacuum pump 7 to pump a certain vacuum in the loop to remove the loop gas; then inject water into the experimental loop with the water pump 1, and observe whether the reading of the pressure sensor P1 changes during this period; when the reading of P1 changes, turn off the water pump 1, close the valve A1, and stop injecting water; then sequentially close the valves A15, A9, and the vacuum pump 7; turn on the lead-bismuth pump 2 and obtain the required flow rate by adjusting the large valve A2; then conduct steady-state debugging, and during this period, take away the excess heat generated by the water driven by the lead-bismuth pump 2 by adjusting the heat exchanger 6 to maintain the water in the experiment at the required temperature; after the loop operates stably for two minutes, conduct real-time acquisition of experimental data. The pressure sensors P2 and P3 respectively measure the inlet and outlet pressures of the experimental section 5, and the temperature sensors T4, T5, and T6 respectively measure the inlet temperature of the experimental section 5, the temperature of the experimental section 5, and the outlet temperature of the experimental section 5; after the experiment is completed, turn off the lead-bismuth pump 2; then open the valve A6 to drain the water in the loop; after the water in the loop is drained, close all the valves, cut off the power supply, and the water flow-induced vibration experiment ends.

[0045] Carry out the lead-bismuth flow-induced vibration experiment: Before conducting the lead-bismuth flow-induced vibration experiment, turn on the heating tape outside the pipeline through which the lead-bismuth in the experimental system will flow, preheat the pipeline to 200 °C, and at the same time heat and melt the lead-bismuth in the lead-bismuth storage tank 10 and heat it to the required temperature; then open the small valve A3, valves A4, A9, A15, and turn on the vacuum pump 7 to remove the air in the loop; then open valves A11, A12, A13, A5; then turn on the argon gas device, open valve A14, gradually open and adjust valve A8 to pressurize the gas space above the liquid lead-bismuth in the lead-bismuth storage tank 10, and gradually press the lead-bismuth into the experimental loop. During this period, observe whether the reading of the pressure sensor P1 changes; when the reading of P1 changes, that is, when the liquid level reaches P1, stop pressurizing the argon gas device and close valves A5, A8, A14; then open valve A10, and keep the vacuum device on during the experiment to remove the air in the experimental loop and keep the inside of the storage tank under negative pressure so that the lead-bismuth can flow back into the storage tank in case of an accident; then turn on the lead-bismuth pump 2 and obtain the required lead-bismuth flow rate by adjusting the small valve A2; then turn off the heating of the heating tape, and the lead-bismuth in the lead-bismuth storage tank 10 remains in the liquid phase; then carry out steady-state debugging. During this period, adjust the heat exchanger 6 to take away the excess heat generated by the lead-bismuth pump driving the lead-bismuth and maintain the lead-bismuth in the experiment at the required temperature; after the loop runs steadily for two minutes, carry out real-time acquisition of experimental data. The pressure sensors P2 and P3 measure the inlet and outlet pressures of the experimental section 5 respectively, and the temperature sensors T4, T5, T6 measure the inlet temperature of the experimental section 5, the temperature of the experimental section 5, and the outlet temperature of the experimental section 5 respectively; during the whole experimental process, monitor whether the local temperature is lower than the lead-bismuth solidification temperature through the temperature sensors in the experimental loop. When the local temperature is too low, turn on the heating tape to prevent blockage accidents; after the experiment is completed, close the secondary loop of the heat exchanger 6, turn on the heating of the heating tape, and at the same time turn off the lead-bismuth pump 2; then close valve A9; then open valve A5; then turn on the argon gas device, open valve A14, gradually open and adjust valve A7 to pressurize the top of the expansion tank of the experimental loop and press the lead-bismuth back into the expansion tank. During this period, calculate the lead-bismuth liquid level based on the pressures measured by the pressure sensors at the top and bottom of the lead-bismuth storage tank 10 to determine the recovery amount of the lead-bismuth. After the lead-bismuth is completely recovered, turn off the argon gas device, A14, valve A7, A5 in sequence, and then turn off valves A15, vacuum pump 7, valve A10 in sequence, cut off the power supply, and the experiment ends.

[0046] Treatment plan in case of equipment failure: When there is a break and leakage in the loop during the experiment: First, open valve A5, then turn off the lead-bismuth pump, then close valve A9, and keep valve A10 open until the lead-bismuth is recovered without leakage; when a pressure sensor or temperature sensor in a subsystem of the lead-bismuth storage system fails, use the argon gas device to press all the lead-bismuth into the other two subsystems, and then replace the failed pressure sensor and temperature sensor.

[0047] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A lead-bismuth flow-induced vibration experimental device, characterized in that, it includes a lead-bismuth flow-induced vibration device, a lead-bismuth liquid storage device, a vacuum device and an argon device; the lead-bismuth flow-induced vibration device includes a lead-bismuth pump (2), a vibration isolation hose R1, an expansion tank (3), a buffer tank (4), an experimental section (5), a vibration isolation hose R2 and a heat exchanger (6), the lead-bismuth pump (2) is connected to the expansion tank (3) through the vibration isolation hose R1, a water pump (1) is connected between the lead-bismuth pump (2) and the expansion tank (3), and a valve A1 is arranged in front of the water pump (1); the expansion tank (3) is connected to the buffer tank (4), the buffer tank (4) is connected to the inlet of the experimental section (5), one end of the outlet of the experimental section (5) is connected to the heat exchanger (6), and the other end of the outlet of the experimental section (5) is connected to the bottom of the lead-bismuth liquid storage device; the top of the lead-bismuth liquid storage device is respectively connected to the vacuum device and the argon device, the top of the lead-bismuth liquid storage device is also connected to the top of the expansion tank (3), the vacuum device and the argon device are respectively connected to the top of the expansion tank (3); the lead-bismuth liquid storage device includes three identical subsystems, and each subsystem of the lead-bismuth liquid storage device includes a lead-bismuth storage tank (10), heat-conducting oil (11) and a heat-conducting oil tank (12), the heat-conducting oil (11) is in the heat-conducting oil tank (12), and the heat-conducting oil tank (12) is installed in the lead-bismuth storage tank (10).

2. The lead-bismuth flow-induced vibration experimental device according to claim 1, characterized in that, a large valve A2 and a temperature sensor T2 are arranged between the expansion tank (3) and the buffer tank (4), a pipeline connected to the pipeline connecting the expansion tank (3) and the buffer tank (4) is connected, and a valve A3 and a temperature sensor T3 are installed; a temperature sensor T1 and a pressure sensor P1 are arranged on the expansion tank (3).

3. The lead-bismuth flow-induced vibration experimental device according to claim 1 or 2, characterized in that, a pressure sensor P2 and a temperature sensor T4 are arranged between the buffer tank (4) and the experimental section (5).

4. The lead-bismuth flow-induced vibration experimental device according to claim 3, characterized in that, a valve A4 and a temperature sensor T7 are installed between the experimental section (5) and the heat exchanger (6), a temperature sensor T5 is installed on the experimental section (5), a pressure sensor P3 and a temperature sensor T6 are installed at the connection section of the lower end of the experimental section (5) and the pipeline, and a valve A5 is installed between the experimental section (5) and the lead-bismuth liquid storage device.

5. The lead-bismuth flow-induced vibration experimental device according to claim 4, characterized in that, a valve A8 and a valve A7 are arranged on the pipeline connecting the top of the lead-bismuth liquid storage device and the top of the expansion tank (3).

6. The lead-bismuth flow-induced vibration experimental device according to claim 5, characterized in that, the vacuum device includes a vacuum pump (7), and a valve A15 is arranged in front of the vacuum pump (7).

7. The lead-bismuth flow-induced vibration experimental device according to claim 6, characterized in that, The argon gas device consists of 8 bottles of argon gas (8) and a main pipe (9). The argon gas (8) is connected to the main pipe (9), and the main pipe (9) is connected to the pipeline between valve A8 and valve A7, and is provided with valve A14.

8. A lead-bismuth flow-induced vibration experimental device according to claim 7, characterized in that, valve A10 and vacuum gauge P4 are provided on the connection pipeline between the top of the lead-bismuth liquid storage device and the vacuum device, valve A9 and vacuum gauge P5 are provided on the connection pipeline between the top of the bismuth liquid storage device and the argon gas device, and the vacuum device pipeline is connected between valve A9 and valve A10.

9. An experimental method for a lead-bismuth flow-induced vibration experimental device according to claim 8, characterized in that, it includes the following steps: Step 1: Conduct a water flow-induced vibration experiment; Close all valves of the experimental system; open large valve A2, valve A1, valve A4, valve A9, valve A15 and vacuum pump (7); then use water pump (1) to inject water into the experimental loop, and observe whether the reading of pressure sensor P1 changes during this period; when the reading of P1 changes, close water pump (1), then close valve A1, and stop water injection; then close valve A15, valve A9 and vacuum pump (7) in sequence; open lead-bismuth pump (2), and obtain the required flow rate by adjusting large valve A2; then conduct steady-state debugging, and during this period, take away the excess heat generated by the water driven by lead-bismuth pump (2) by adjusting heat exchanger (6) to maintain the water in the experiment at the required temperature; after the loop operates steadily for two minutes, conduct real-time acquisition of experimental data, pressure sensor P2 and pressure sensor P3 respectively measure the inlet and outlet pressures of experimental section (5), and temperature sensors T4, T5 and T6 respectively measure the inlet temperature of experimental section (5), the temperature of experimental section (5), and the outlet temperature of experimental section (5); after the experiment is completed, close lead-bismuth pump (2); then open valve A6 to drain the water in the loop; after the water in the loop is drained, close all valves, cut off the power supply, and the water flow-induced vibration experiment ends; Step 2: Conduct a lead-bismuth flow-induced vibration experiment; Turn on the tracing heating outside the pipeline through which lead-bismuth in the experimental system will flow, preheat the pipeline to 200 °C, and at the same time heat and melt the lead-bismuth in the lead-bismuth storage tank (10) and heat it to the required temperature; open the small valve A3, valve A4, valve A9, valve A15, and turn on the vacuum pump (7) to remove the air in the loop; then open valve A11, valve A12, valve A13, and valve A5; turn on the argon device, open valve A14, gradually open and adjust valve A8 to pressurize the gas space above the liquid lead-bismuth in the lead-bismuth storage tank (10), and gradually press the lead-bismuth into the experimental loop. During this period, observe whether the reading of the pressure sensor P1 changes; when the reading of the pressure sensor P1 changes, that is, when the liquid level reaches P1, stop pressurizing the argon device and close valve A5, valve A8, and valve A14; then open valve A10. Keep the vacuum system on during the experiment and keep the inside of the storage tank under negative pressure; then turn on the lead-bismuth pump (2) and obtain the required lead-bismuth flow rate by adjusting the small valve A2; then turn off the tracing heating, and the lead-bismuth in the lead-bismuth storage tank (10) should always remain in the liquid phase; then conduct steady-state debugging. During this period, take away the excess heat generated by the lead-bismuth pump driving the lead-bismuth through the heat exchanger (6) to maintain the lead-bismuth in the experiment at the required temperature; after the loop runs steadily for two minutes, conduct real-time acquisition of experimental data. The pressure sensor P2 and the pressure sensor P3 respectively measure the inlet and outlet pressures of the experimental section (5), and the temperature sensors T4, T5, and T6 respectively measure the inlet temperature of the experimental section (5), the temperature of the experimental section (5), and the outlet temperature of the experimental section (5); during the whole experiment, monitor whether the local temperature is lower than the lead-bismuth solidification temperature through each temperature sensor in the experimental loop; after the experiment is completed, close the secondary loop of the heat exchanger (6), turn on the tracing heating, and at the same time turn off the lead-bismuth pump (2); then close valve A9 and open valve A5; then turn on the argon device, open valve A14, gradually open and adjust valve A7 to pressurize the top of the expansion tank of the experimental loop, and press the lead-bismuth back into the expansion tank. During this period, convert the pressure measured by the pressure sensors at the top and bottom of the lead-bismuth storage tank (10) to obtain the lead-bismuth liquid level to determine the recovery amount of lead-bismuth. After the lead-bismuth is completely recovered, turn off the argon device, valve A14, valve A7, and valve A5 in sequence, and then turn off valve A15, the vacuum pump (7), and valve A10 in sequence, and cut off the power supply, and the experiment ends.

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