High-temperature supercritical carbon dioxide steady-state jet flow experimental device and method

Abstract

The invention discloses a high-temperature supercritical carbon dioxide steady-state jet flow experiment device and method, and the device comprises a liquid storage tank, a liquid booster pump, a plunger pump, a first mass flow meter, a second mass flow meter, a heating section, a first electric control valve, a first-stage cooler, a second-stage condenser, a back pressure valve, and a main loop system composed of related pipe fittings and equipment. The gas supply system consists of a carbon dioxide gas cylinder group, a gas storage tank, a gas booster pump and related pipe fittings and equipment; and the jet experiment section consists of a spray pipe, a second electric control valve, an electric stop valve and related pipe fittings and equipment. The invention further provides an experimental method of the device. According to the invention, the steady-state jet flow experiment research of supercritical carbon dioxide under the high-temperature condition can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear reactor thermal-hydraulic experiments, and particularly relates to a high-temperature supercritical carbon dioxide steady jet experiment device and method. Background Art

[0002] Supercritical carbon dioxide has characteristics such as high density, low viscosity, good heat transfer performance, and easy compressibility near the pseudo-critical parameters. As an energy conversion working fluid applied to the Brayton cycle power generation system, it can significantly improve the energy conversion efficiency, reduce the equipment volume, and enhance the system safety, which is the development direction of future advanced energy system innovation. In addition, supercritical carbon dioxide can also be used as a nuclear reactor coolant due to its excellent nuclear physical properties and stability. However, in the actual operation of these systems, the loss-of-pressure accident is a potential safety hazard that cannot be ignored.

[0003] The loss-of-pressure accident is usually caused by material corrosion, mechanical damage, structural defects, or operational errors, resulting in pipeline rupture or equipment failure. The high-speed jet formed by the leakage of high-pressure and high-temperature supercritical carbon dioxide will cause serious thermal shock to the surrounding equipment, pipelines, and structural materials. The high-pressure and high-temperature supercritical carbon dioxide high-speed jet directly impacts the equipment surface, accompanied by high-frequency vibration and severe temperature gradient, resulting in a significant increase in the thermal stress of the material. This thermal shock will not only accelerate the aging and fatigue of the material, but may also cause instantaneous rupture or failure of the equipment, thus endangering the overall safety of the system.

[0004] To address this potential risk, understanding the jet behavior characteristics of high-temperature supercritical carbon dioxide in the loss-of-pressure accident and its thermal damage mechanism to the surrounding equipment is the key technical challenge for ensuring the safe operation of the Brayton cycle system and the nuclear reactor system. Therefore, carrying out the research on the thermal shock effect of the high-temperature supercritical carbon dioxide loss-of-pressure accident has important theoretical significance and practical application value. Summary of the Invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a high-temperature supercritical carbon dioxide steady jet experiment device and method, to provide an experimental device and method for studying the experimental phenomena of high-temperature supercritical carbon dioxide jet impact. The experimental device of the present invention can carry out the steady jet experiment of supercritical carbon dioxide under high-temperature conditions, and study the influence laws of parameters such as system pressure, temperature, and break morphology on the jet impact characteristics of high-temperature supercritical carbon dioxide.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A high-temperature supercritical carbon dioxide steady jet experiment device, comprising a main loop system, a condensation system, and an electric heating system;

[0008] The main circuit system includes a liquid storage tank 1, a liquid booster pump 2, a plunger pump 3, a first mass flowmeter 4, a regulating valve 5, a heating section 6, a first electric regulating valve 7, a primary cooler 8, a secondary condenser 9, a back pressure valve 10, and a second mass flowmeter 11. The bottom outlet of the liquid storage tank 1 is connected to the inlet of the liquid booster pump 2. The outlet of the liquid booster pump 2 is connected to the inlet of the plunger pump 3. The outlet of the plunger pump 3 is connected to the inlet of the first mass flowmeter 4. The outlet of the first mass flowmeter 4 is connected to one end of the regulating valve 5. The other end of the regulating valve 5 is connected to the inlet of the heating section 6. The outlet of the heating section 6 is connected to one end of the first electric regulating valve 7. The other end of the first electric regulating valve 7 is connected to the inlet of the primary cooler 8. The outlet of the primary cooler 8 is connected to the inlet of the secondary condenser 9. The outlet of the secondary condenser 9 is connected to one end of the back pressure valve 10. The other end of the back pressure valve 10 is connected to the inlet of the second mass flowmeter 11. The outlet of the second mass flowmeter 11 is connected to the side inlet of the liquid storage tank 1.

[0009] The gas supplementing system includes a carbon dioxide gas cylinder group 12, a gas storage tank 13, and a gas booster pump 14. The carbon dioxide gas cylinder group 12 is connected to the inlet of the gas storage tank 13. The outlet of the gas storage tank 13 is connected to the inlet of the gas booster pump 14. The outlet of the gas booster pump 14 is connected to the top inlet of the liquid storage tank 1.

[0010] The jet experiment section includes a nozzle 17, a second electric regulating valve 16, and an electric stop valve 15. One end of the electric stop valve 15 is connected to the outlet of the heating section 6. The other end of the electric stop valve 15 is connected to one end of the second electric regulating valve 16. The other end of the second electric regulating valve 16 is connected to the nozzle 17.

[0011] Preferably, the gas supplementing system supplements carbon dioxide to the main circuit system through the carbon dioxide gas cylinder group 12, the gas storage tank 13, and the gas booster pump 14, maintains the pressure of the liquid storage tank 1, and realizes the steady operation of the high-temperature supercritical carbon dioxide steady-state jet experiment device.

[0012] Preferably, the main circuit system increases the pressure of carbon dioxide at the bottom outlet of the liquid storage tank 1 through the liquid booster pump 2, ensures that the carbon dioxide at the inlet of the plunger pump 3 is in a subcooled state, and prevents cavitation.

[0013] Preferably, the first mass flowmeter 4 of the main circuit system is located in front of the heating section 6, and the second mass flowmeter 11 is located behind the secondary condenser 9. The fluids measured by the first mass flowmeter 4 and the second mass flowmeter 11 are both single-phase liquids, and high-precision mass flowmeters can be used.

[0014] Preferably, the jet flow rate of the jet test section is indirectly obtained through the first mass flowmeter 4 and the second mass flowmeter 11 of the main loop system; when the high-temperature supercritical carbon dioxide steady jet experimental device operates stably, the flow rate value measured by the first mass flowmeter 4 minus the flow rate value measured by the second mass flowmeter 11 is the jet flow rate of the nozzle 17 test section.

[0015] Preferably, the main loop system uses a primary cooler 8 and a secondary condenser 9 to fractionally condense a part of the high-temperature supercritical carbon dioxide at the outlet of the heating section 6 into a liquid state, and the liquid carbon dioxide returns to the liquid storage tank 1 through a back pressure valve 10 and the second mass flowmeter 11 to continue cooling the carbon dioxide supplemented by the gas replenishing system.

[0016] Preferably, the main loop system, the container, pipelines and valves of the nozzle 17 test section are wrapped with aerogel thermal insulation cotton for effective thermal insulation.

[0017] For the experimental method corresponding to the experimental device, before the experiment, the experimental device is filled with water for leak detection, hydrostatic test and airtightness test to ensure that there is no leakage in the loop under high pressure;

[0018] Carbon dioxide gas is filled into the gas storage tank 13 through the carbon dioxide gas cylinder group 12. When the pressure of the gas storage tank 13 is balanced with the pressure of the carbon dioxide gas cylinder group 12, the connection of the carbon dioxide gas cylinder group 12 is disconnected;

[0019] Start the gas booster pump 14 to fill carbon dioxide gas into the liquid storage tank 1. When the carbon dioxide in the liquid storage tank 1 is liquefied after being pressurized, turn off the gas booster pump 14;

[0020] Turn on the primary cooler 8 and the secondary condenser 9;

[0021] Start the liquid booster pump 2 and the plunger pump 3, adjust the working frequency of the plunger pump 3 so that the liquid carbon dioxide passes through the primary cooler 8 and the secondary condenser 9 in sequence and returns to the liquid storage tank 1, so that the temperature of the carbon dioxide liquid in the liquid storage tank 1 is reduced to reach the experimental target working condition temperature;

[0022] Adjust the working frequency of the plunger pump 3 and adjust the back pressure valve 10 to make the pressure of the main loop system reach the experimental target working condition pressure;

[0023] Adjust the regulating valve 5 and adjust the first electric regulating valve 7 to make the carbon dioxide mass flow rate of the main loop system greater than the predicted value of the jet flow rate under the experimental target working condition;

[0024] Start the heating section 6, gradually and slowly increase the heating power of the heating section 6, and ensure that each power increase does not exceed 5% of the current heating power until the temperature of the supercritical carbon dioxide at the outlet of the heating section 6 reaches the experimental target working condition temperature;

[0025] Adjust the primary cooler 8 and the secondary condenser 9 to ensure that supercritical carbon dioxide condenses into a liquid state;

[0026] After the main loop system is stable, start the gas booster pump 14, open the electric stop valve 15, slowly adjust the second electric control valve 16, gradually increase the jet flow rate of the nozzle 17 until the critical jet flow rate is reached. At the same time, adjust the back pressure valve 10 and the first electric control valve 7 to make the pressure of the main loop system the pressure of the experimental target working condition. After the experimental device reaches stability, start recording the experimental data;

[0027] After the experiment is completed, gradually and slowly reduce the heating power of the heating section 6 until it reaches 0;

[0028] Adjust the back pressure valve 10 and the first electric control valve 7 to reduce the pressure of the main loop system;

[0029] Close the electric stop valve 15, the second electric control valve 16, the gas booster pump 14, the liquid booster pump 2 and the plunger pump 3, and the primary cooler 8 and the secondary condenser 9 in sequence, and the experiment ends.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The experimental device and method of the present invention realize the supercritical carbon dioxide jet experiment under high temperature conditions, and achieve the steady-state jet of supercritical carbon dioxide through the air supplement system and the control of the electric control valve.

[0032] 2. The jet flow rate value is indirectly measured by using two mass flow meters. The first mass flow meter 4 of the main loop system is located in front of the heating section 6, and the second mass flow meter 11 is located behind the secondary condenser 9. The fluids measured by the first mass flow meter 4 and the second mass flow meter 11 are both single-phase liquids, and high-precision mass flow meters can be used for measurement, which is more accurate than the method of directly measuring the high-temperature gas flow rate value.

[0033] 3. A part of the high-temperature supercritical carbon dioxide at the outlet of the heating section 6 is jetted into the atmosphere through the nozzle, and another part of the high-temperature supercritical carbon dioxide is condensed into a liquid state through the primary cooler 8 and the secondary condenser 9 in stages. The liquid carbon dioxide returns to the liquid storage tank 1 and continues to cool the carbon dioxide supplemented by the air supplement system, so as to keep the temperature of the liquid storage tank 1 stable and ensure that the inlet of the plunger pump 3 is liquid carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall experimental device. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be described in detail below with reference to the drawings and examples:

[0036] As shown in the attachedFigure 1 As shown, the present invention relates to a high-temperature supercritical carbon dioxide steady-state jet experimental device, including a main circuit system, an air supply system, and a jet experimental section; the main circuit system includes a liquid storage tank 1, a liquid booster pump 2, a plunger pump 3, a first mass flow meter 4, a second mass flow meter 11, a regulating valve 5, a heating section 6, a first electric regulating valve 7, a primary cooler 8, a secondary condenser 9, a back pressure valve 10 and a second mass flow meter 11; wherein the bottom outlet of the liquid storage tank 1 is connected to the inlet of the liquid booster pump 2; the outlet of the liquid booster pump 2 is connected to the inlet of the plunger pump 3, and the carbon dioxide pressure at the bottom outlet of the liquid storage tank 1 is increased by the liquid booster pump 2 to ensure that the carbon dioxide at the inlet of the plunger pump 3 is in a supercooled state to prevent cavitation; the outlet of the plunger pump 3 is connected to the inlet of the first mass flow meter 4; the first mass flow meter 4 is connected to the outlet of the first mass flow meter 4; The outlet of meter 4 is connected to one end of regulating valve 5; the other end of regulating valve 5 is connected to the inlet of heating section 6; the outlet of heating section 6 is connected to one end of first electric regulating valve 7; the other end of first electric regulating valve 7 is connected to the inlet of primary cooler 8; the outlet of primary cooler 8 is connected to the inlet of secondary condenser 9; the outlet of secondary condenser 9 is connected to one end of back pressure valve 10; the other end of back pressure valve 10 is connected to the inlet of second mass flowmeter 11; the outlet of second mass flowmeter 11 is connected to the side inlet of liquid storage tank 1; the main loop system condenses part of high-temperature supercritical carbon dioxide at the outlet of heating section 6 into liquid by stages through primary cooler 8 and secondary condenser 9, and the liquid carbon dioxide returns to liquid storage tank 1 through back pressure valve 10 and second mass flowmeter 11, and continues to cool the carbon dioxide supplemented by the air replenishment system.

[0037] The gas replenishment system includes a carbon dioxide cylinder group 12, a gas storage tank 13 and a gas booster pump 14; through the carbon dioxide cylinder group 12, the gas storage tank 13 and the gas booster pump 14, carbon dioxide is replenished for the main loop system to maintain the pressure of the liquid storage tank 1, so as to achieve the steady-state operation of the experimental device of the present invention. The carbon dioxide cylinder group 12 is connected to the inlet of the gas storage tank 13; the outlet of the gas storage tank 13 is connected to the inlet of the gas booster pump 14; the outlet of the gas booster pump 14 is connected to the top inlet of the liquid storage tank 1.

[0038] The jet test section includes a nozzle 17, a second electric regulating valve 16 and an electric stop valve 15; one end of the electric stop valve 15 is connected to the outlet of the heating section 6, and the other end of the electric stop valve 15 is connected to one end of the second electric regulating valve 16; the other end of the second electric regulating valve 16 is connected to the nozzle 17. The jet flow rate of the jet test section is indirectly obtained through the first mass flowmeter 4 and the second mass flowmeter 11 of the main loop system; when the experimental device of the present invention is in steady state operation, the flow value measured by the first mass flowmeter 4 minus the flow value measured by the second mass flowmeter 11 is the jet flow rate of the test section of the nozzle 17.

[0039] like Figure 1As shown in the figure, the present invention relates to an experimental method for a high-temperature supercritical carbon dioxide steady jet experimental device: Before the experiment starts, the experimental device is filled with water for leak detection, hydraulic pressure test, and airtightness test to ensure that there is no leakage in the loop under the preset working conditions; carbon dioxide gas is filled into the gas storage tank 13 through the carbon dioxide gas cylinder group 12. When the pressure of the gas storage tank 13 is balanced with the pressure of the carbon dioxide gas cylinder group 12, the connection of the carbon dioxide gas cylinder group 12 is disconnected; the gas booster pump 14 is started to fill carbon dioxide gas into the liquid storage tank 1. When the carbon dioxide in the liquid storage tank 1 is liquefied after being pressurized, the gas booster pump 14 is closed; the primary cooler 8 and the secondary condenser 9 are turned on; the liquid booster pump 2 and the plunger pump 3 are started, and the working frequency of the plunger pump 3 is adjusted so that the liquid carbon dioxide passes through the primary cooler 8 and the secondary condenser 9 in sequence and returns to the liquid storage tank 1, reducing the temperature of the carbon dioxide liquid in the liquid storage tank 1 to reach the experimental target working condition temperature; the working frequency of the plunger pump 3 is adjusted, and the back pressure valve 10 is adjusted to make the pressure of the main loop system reach the experimental target working condition pressure; the regulating valve 5 is adjusted, and the first electric regulating valve 7 is adjusted to make the carbon dioxide mass flow rate in the main loop system greater than the predicted value of the jet flow rate under the experimental target working condition, so that a part of the carbon dioxide can be condensed into a liquid state after passing through the primary cooler 8 and the secondary condenser 9. The liquid carbon dioxide returns to the liquid storage tank 1 to continue cooling the carbon dioxide supplemented by the air replenishment system, keeping the temperature of the liquid storage tank 1 stable and ensuring that the inlet of the plunger pump 3 is liquid carbon dioxide; the heating section 6 is started, and the heating power of the heating section 6 is gradually and slowly increased. Each time the power is increased, it is ensured that it does not exceed 5% of the current heating power to avoid sudden increase in system pressure caused by rapid phase change of carbon dioxide due to too fast heating. During the heating process, the system pressure is stabilized by adjusting the back pressure valve 10; until the temperature of the supercritical carbon dioxide at the outlet of the heating section 6 reaches the experimental target working condition temperature; the primary cooler 8 and the secondary condenser 9 are adjusted to ensure that the supercritical carbon dioxide is condensed into a liquid state, so that the fluids measured by the first mass flowmeter 4 and the second mass flowmeter 11 are both single-phase liquids, and high-precision mass flowmeters can be used for measurement, which is more accurate than the method of directly measuring the high-temperature gas flow rate value; after the main loop system is stable, the gas booster pump 14 is turned on, the electric stop valve 15 is opened, the second electric regulating valve 16 is slowly adjusted, and the jet flow rate of the nozzle 17 is gradually increased until the critical jet flow rate is reached. At the same time, the back pressure valve 10 is adjusted, and the first electric regulating valve 7 is adjusted to make the pressure of the main loop system the experimental target working condition pressure. After the experimental device reaches stability, the experimental data is started to be recorded; after the experiment is completed, the heating power of the heating section 6 is gradually and slowly reduced until it is 0; the back pressure valve 10 is adjusted, and the first electric regulating valve 7 is adjusted to reduce the pressure of the main loop system; the electric stop valve 15, the second electric regulating valve 16, the gas booster pump 14, the liquid booster pump 2 and the plunger pump 3, and the primary cooler 8 and the secondary condenser 9 are closed in sequence, and the experiment ends.

Claims

1. A high-temperature supercritical carbon dioxide steady-state jet experimental device, characterized in that: It includes a main loop system, a gas charging system and a jet experiment section; The main loop system includes a liquid storage tank (1), a liquid booster pump (2), a plunger pump (3), a first mass flowmeter (4), a regulating valve (5), a heating section (6), a first electric regulating valve (7), a primary cooler (8), a secondary condenser (9), a back pressure valve (10) and a second mass flowmeter (11); the bottom outlet of the liquid storage tank (1) is connected to the inlet of the liquid booster pump (2); the outlet of the liquid booster pump (2) is connected to the inlet of the plunger pump (3); the outlet of the plunger pump (3) is connected to the inlet of the first mass flowmeter (4); the outlet of the first mass flowmeter (4) is connected to one end of the regulating valve (5); the other end of the regulating valve (5) is connected to the inlet of the heating section (6); the outlet of the heating section (6) is connected to one end of the first electric regulating valve (7); the other end of the first electric regulating valve (7) is connected to the inlet of the primary cooler (8); the outlet of the primary cooler (8) is connected to the inlet of the secondary condenser (9); the outlet of the secondary condenser (9) is connected to one end of the back pressure valve (10); the other end of the back pressure valve (10) is connected to the inlet of the second mass flowmeter (11); the outlet of the second mass flowmeter (11) is connected to the side inlet of the liquid storage tank (1); The gas charging system includes a carbon dioxide gas cylinder group (12), a gas storage tank (13) and a gas booster pump (14); the carbon dioxide gas cylinder group (12) is connected to the inlet of the gas storage tank (13); the outlet of the gas storage tank (13) is connected to the inlet of the gas booster pump (14); the outlet of the gas booster pump (14) is connected to the top inlet of the liquid storage tank (1); The jet experiment section includes a nozzle (17), a second electric regulating valve (16) and an electric stop valve (15); one end of the electric stop valve (15) is connected to the outlet of the heating section (6), and the other end of the electric stop valve (15) is connected to one end of the second electric regulating valve (16); the other end of the second electric regulating valve (16) is connected to the nozzle (17).

2. The high-temperature supercritical carbon dioxide steady-state jet experimental device according to claim 1, characterized in that: The gas charging system supplements carbon dioxide to the main loop system through the carbon dioxide gas cylinder group (12), the gas storage tank (13) and the gas booster pump (14), maintains the pressure of the liquid storage tank (1), and realizes the steady operation of the high-temperature supercritical carbon dioxide steady jet experiment device.

3. The high-temperature supercritical carbon dioxide steady-state jet experimental device according to claim 1, wherein: The main loop system increases the carbon dioxide pressure at the bottom outlet of the liquid storage tank (1) through the liquid booster pump (2), ensures that the carbon dioxide at the inlet of the plunger pump (3) is in a subcooled state, and prevents cavitation.

4. A high-temperature supercritical carbon dioxide steady jet experimental device according to claim 1, characterized in that: The first mass flowmeter (4) of the main loop system is located in front of the heating section (6), and the second mass flowmeter (11) is located behind the secondary condenser (9). The fluids measured by the first mass flowmeter (4) and the second mass flowmeter (11) are both single-phase liquids, and are measured by a mass flowmeter with an accuracy of 0.1%.

5. A high-temperature supercritical carbon dioxide steady-state jet experimental device according to claim 1, characterized in that: The jet flow rate of the jet experiment section is indirectly obtained through the first mass flowmeter (4) and the second mass flowmeter (11) of the main loop system; when the high-temperature supercritical carbon dioxide steady jet experiment device operates steadily, the flow rate value measured by the first mass flowmeter (4) minus the flow rate value measured by the second mass flowmeter (11) is the jet flow rate of the nozzle (17) test section.

6. The high-temperature supercritical carbon dioxide steady-state jet experimental device according to claim 1, wherein: The main circuit system condensates a part of the high-temperature supercritical carbon dioxide at the outlet of the heating section (6) into liquid state through a primary cooler (8) and a secondary condenser (9). The liquid carbon dioxide returns to the liquid storage tank (1) through a back pressure valve (10) and a second mass flowmeter (11), and continues to cool the carbon dioxide supplemented by the gas makeup system.

7. A high-temperature supercritical carbon dioxide steady jet experimental device according to claim 1, characterized in that: The main circuit system, the containers, pipelines and valves of the test section of the nozzle (17) are wrapped with aerogel thermal insulation cotton for effective heat insulation.

8. The experimental method corresponding to the experimental device according to any one of claims 1 to 7, characterized in that: Before the experiment, the experimental device is filled with water for leak detection, hydrostatic test and airtightness test to ensure that there is no leakage in the loop under high pressure. Carbon dioxide gas is filled into the gas storage tank (13) through a carbon dioxide gas cylinder group (12). When the pressure of the gas storage tank (13) is balanced with the pressure of the carbon dioxide gas cylinder group (12), the connection of the carbon dioxide gas cylinder group (12) is disconnected. The gas booster pump (14) is started to fill carbon dioxide gas into the liquid storage tank (1). When the carbon dioxide in the liquid storage tank (1) is liquefied after being pressurized, the gas booster pump (14) is closed. The primary cooler (8) and the secondary condenser (9) are turned on. The liquid booster pump (2) and the plunger pump (3) are started, and the working frequency of the plunger pump (3) is adjusted so that the liquid carbon dioxide passes through the primary cooler (8) and the secondary condenser (9) in sequence and returns to the liquid storage tank (1), reducing the temperature of the carbon dioxide liquid in the liquid storage tank (1) to reach the experimental target working condition temperature. The working frequency of the plunger pump (3) is adjusted, and the back pressure valve (10) is adjusted to make the pressure of the main circuit system reach the experimental target working condition pressure. The regulating valve (5) is adjusted, and the first electric regulating valve (7) is adjusted to make the carbon dioxide mass flow rate of the main circuit system greater than the estimated value of the jet flow rate under the experimental target working condition. The heating section (6) is started, and the heating power of the heating section (6) is gradually and slowly increased. Each time the power is increased, it is ensured that the increase does not exceed 5% of the current heating power until the temperature of the supercritical carbon dioxide at the outlet of the heating section (6) reaches the experimental target working condition temperature. The primary cooler (8) and the secondary condenser (9) are adjusted to ensure that the supercritical carbon dioxide is condensed into liquid state. After the main circuit system is stable, the gas booster pump (14) is started, the electric stop valve (15) is opened, the second electric regulating valve (16) is slowly adjusted, and the jet flow rate of the nozzle (17) is gradually increased until the critical jet flow rate is reached. At the same time, the back pressure valve (10) is adjusted, and the first electric regulating valve (7) is adjusted to make the pressure of the main circuit system the experimental target working condition pressure. When the experimental device reaches stability, the experimental data is started to be recorded. After the experiment is completed, the heating power of the heating section (6) is gradually and slowly reduced until it is 0. The back pressure valve (10) is adjusted, and the first electric regulating valve (7) is adjusted to reduce the pressure of the main circuit system. The electric stop valve (15), the second electric regulating valve (16), the gas booster pump (14), the liquid booster pump (2) and the plunger pump (3), the primary cooler (8) and the secondary condenser (9) are closed in sequence, and the experiment ends.

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