Thermal behavior experiment system and method for narrow rectangular channel under reflooding cooling condition

Abstract

The invention provides a thermal behavior experiment system and method under a narrow rectangular channel reflooding cooling condition. The system comprises a heating water storage tank, a nitrogen tank, a steam tank, a shield pump, a preheating section, a first direct-current power supply, a second direct-current power supply, a narrow rectangular channel test section, a steam-water separator, a surge tank, a flow control valve, a silencer and an electromagnetic valve. The experimental working medium is deionized water, and re-submerging cooling experiments under different system pressures, working medium supercooling degrees, heating wall surface heat flux densities, working medium submerging speeds, heating wall surface initial temperatures and channel interior initial liquid levels can be carried out on an experimental section of a narrow rectangular channel structure. The device is suitable for narrow rectangular channel structures with different sizes, and can be used for carrying out re-submerging experiments on experiment sections with single-plate double-channel, double-plate three-channel and more channels. The system pressure and the inlet flow in the submerging process can be kept stable, and it can be ensured that the supercooling degree of a working medium, the heating wall surface temperature and the initial liquid level are controllable.

Description

Technical Field

[0001] The present invention relates to the technical field of reflood cooling experiments, and particularly to a thermal-hydraulic behavior experimental system and method under the condition of reflood cooling in a narrow rectangular channel. Background Art

[0002] Due to the complexity of its physical mechanism and the important application value in industrial fields such as nuclear energy, refrigeration, and rocket engines, the submergence cooling of highly overheated surfaces has always attracted much attention. To better study the physical phenomena in the submergence cooling process, the currently feasible and mainstream way is to continuously deepen the understanding of the evolution mechanism of the submergence cooling process through a series of experiments. Most of the currently mature experimental methods are aimed at rod bundles, circular tubes, and annular channels. The submergence cooling experiment of highly overheated surfaces in a narrow rectangular channel not only requires the realization of flow transient regulation, pressure feedback control, and the rapid matching regulation of various thermal-hydraulic parameters in a short time, but also requires the realization of high-temperature heating and wall temperature transient measurement in the narrow internal space of the structure. The experimental difficulty is relatively high, and the experimental method still has deficiencies.

[0003] Therefore, it is necessary to develop a thermal-hydraulic behavior experimental method for reflood cooling in a narrow rectangular channel. This experimental method has the ability to carry out corresponding reflood experiments on narrow rectangular channels, has high-precision control of corresponding thermal-hydraulic parameters, ensures real-time monitoring of key parameters in the experimental process, ensures good insulation performance of the experimental section, loop power supply, preheating section, etc., and ensures the safety of experimental personnel. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a thermal-hydraulic behavior experimental system and method under the condition of reflood cooling in a narrow rectangular channel.

[0005] A thermal-hydraulic behavior experimental system under the condition of reflood cooling in a narrow rectangular channel includes: a heating water storage tank, a nitrogen gas tank, a steam tank, a canned motor pump, a preheating section, a first DC power supply, a second DC power supply, a narrow rectangular channel test section, a steam-water separator, a pressure stabilizing tank, a flow control valve, a muffler, and a solenoid valve;

[0006] The nitrogen gas tank is connected to the heating water storage tank; the heating water storage tank, the steam tank, and the flow control valve form a steam circulation loop; the heating water storage tank is also sequentially connected to the canned motor pump, the preheating section, and the flow control valve to form a water circulation loop; both ends of the preheating section are connected to the first DC power supply; the flow control valve is also connected to the solenoid valve; the solenoid valve is connected to the narrow rectangular channel test section; both ends of the narrow rectangular channel test section are connected to the second DC power supply; the narrow rectangular channel test section is connected to the steam-water separator; the steam-water separator is connected to the pressure stabilizing tank; the pressure stabilizing tank is connected to the muffler.

[0007] In one embodiment, it further includes: a first drain valve, a first temperature sensor, a first pressure sensor, and a first exhaust valve;

[0008] The first drain valve, the first temperature sensor, the first pressure sensor, and the first exhaust valve are connected to the heating water storage tank.

[0009] In one embodiment, it further includes: a second temperature sensor, a second pressure sensor, and a second exhaust valve;

[0010] The second temperature sensor, the second pressure sensor, and the second exhaust valve are connected to the steam tank.

[0011] In one embodiment, it further includes: a second drain valve;

[0012] The second drain valve is connected to the narrow rectangular channel test section.

[0013] In one embodiment, it further includes: a third exhaust valve;

[0014] The third exhaust valve is connected to the steam-water separator.

[0015] In one embodiment, it further includes: a filter, a first electric valve, a second electric valve, a first flowmeter, a first flow sensor, a first stop valve, a second stop valve, a second flow sensor, a second flowmeter, a third electric valve, a third stop valve, a fourth stop valve, a droplet collector, a third flow sensor, a third flowmeter, and a fourth electric valve;

[0016] The filter is arranged between the heating water storage tank and the canned motor pump; the first electric valve, the second electric valve, the first flowmeter, and the first flow sensor are connected in sequence and arranged between the canned motor pump and the preheating section; the first stop valve is arranged between the heating water storage tank and the flow control valve; the second stop valve, the second flow sensor, the second flowmeter, the third electric valve, and the third stop valve are connected in sequence and arranged between the flow control valve and the steam tank; the fourth stop valve is arranged between the flow control valve and the solenoid valve; the droplet collector is connected at the outlet of the steam-water separator, between the steam-water separator and the pressure stabilizing tank; the third flow sensor, the third flowmeter, and the fourth electric valve are connected in sequence and arranged between the pressure stabilizing tank and the muffler.

[0017] In one embodiment, it further includes: a third temperature sensor, a third pressure sensor, a fourth temperature sensor, a fourth pressure sensor, a fifth temperature sensor, a fifth pressure sensor, and a sixth temperature sensor;

[0018] The third temperature sensor and the third pressure sensor are connected between the first stop valve and the flow control valve; the fourth temperature sensor and the fourth pressure sensor are connected between the fourth stop valve and the solenoid valve; the fifth temperature sensor and the fifth pressure sensor are connected between the narrow rectangular channel test section and the steam-water separator; the sixth temperature sensor is connected to the narrow rectangular channel test section.

[0019] A thermal-hydraulic behavior experimental method under the condition of re-flooding of a narrow rectangular channel, which is used for the thermal-hydraulic behavior experimental system under the condition of re-flooding of a narrow rectangular channel as described above, includes:

[0020] Before testing the thermal-hydraulic behavior experimental system under the condition of re-flooding of a narrow rectangular channel, debug the thermal-hydraulic behavior experimental system under the condition of re-flooding of a narrow rectangular channel and set it to the initial state;

[0021] Start the canned motor pump, and make the medium in the heating water storage tank fill the loop through the flow control valve. The nitrogen gas tank continuously supplies inert gas to the heating water storage tank; start the solenoid valve, control the water circulation loop to close, and obtain the closed flow data; close the solenoid valve, control the water circulation loop to open, and obtain the open flow data; obtain the flow difference according to the closed flow data and the open flow data; adjust the flow resistance of the water circulation loop to meet the preset requirements;

[0022] In response to the medium flooding the experimental body, drain the cooled medium in the narrow rectangular channel test section, record the flow resistance adjustment data of the water circulation loop, and simultaneously collect the two-phase flow pattern evolution images of the medium;

[0023] Control the medium to circulate in the water circulation loop, heat the preheating section through the first DC power supply to bring the experimental environment to the experimental condition, and obtain the preset inlet subcooling degree;

[0024] Generate steam through the steam tank, control the steam circulation loop to open, introduce the steam into the narrow rectangular channel test section, and heat the narrow rectangular channel test section through the second DC power supply; obtain the wall temperature data of the experimental body;

[0025] In response to the wall temperature data of the experimental body reaching the initial wall temperature of the experimental condition, close the water circulation loop and the steam circulation loop, open the solenoid valve, and trigger the operation of flooding the experimental body with the medium; collect the two-phase flow evolution images of the experimental body;

[0026] The steam-water mixture in the narrow rectangular channel test section enters the steam-water separator for separation. The pressure stabilizing tank absorbs the pressure fluctuations, so that the thermal-hydraulic behavior experimental system under the condition of re-flooding of a narrow rectangular channel is in a stable environment, and the silencer eliminates the noise during steam discharge;

[0027] In response to the wall temperature data of the experimental body dropping to the saturation temperature, turn off the canned motor pump, the first DC power supply, the second DC power supply, and the solenoid valve, and discharge the cooled medium in the narrow rectangular channel test section.

[0028] In one embodiment, in response to the wall temperature data of the experimental body dropping to the saturation temperature, turn off the canned motor pump and the second DC power supply, turn off the solenoid valve, discharge the cooled medium in the narrow rectangular channel test section, and then further include:

[0029] Obtain the integrity data of the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel, and adjust the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel according to the integrity data.

[0030] In one embodiment, before testing the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel, setting the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel to the initial state includes:

[0031] Prepare deionized water, and inject the deionized water into the heating water storage tank and the steam tank to reach the preset position;

[0032] Obtain the sealing condition and integrity condition of the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel;

[0033] Heat the narrow rectangular channel test section to obtain the response of the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel;

[0034] According to the sealing condition, the integrity condition and the response condition, conduct pre-test debugging on the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel, and set the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel to the initial state.

[0035] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: The present invention can be applied to narrow rectangular channel structures of different sizes, and can carry out re-flooding experiments on test sections with single-board double channels, double-board triple channels and more channel numbers. The present invention can maintain the stability of the system pressure and the inlet flow rate during the flooding process, and can ensure the controllability of the subcooling degree of the working medium, the heating wall temperature, and the initial liquid level. Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel in one embodiment;

[0037] Figure 2 It is a schematic diagram of the main equipment and process of the thermal-hydraulic behavior experimental system under the condition of re-flooding cooling in the narrow rectangular channel in one embodiment;

[0038] Figure 3 It is a detailed structural schematic diagram of the thermal-hydraulic behavior experimental system under the condition of reflood cooling in a narrow rectangular channel in an embodiment.

[0039] In the figure, there are heating water storage tank - 1, nitrogen tank - 2, steam tank - 3, canned motor pump - 4, preheating section - 5, first DC power supply - 6, second DC power supply - 7, narrow rectangular channel test section - 8, steam-water separator - 9, pressure stabilizing tank - 10, flow control valve - 11, muffler - 12, solenoid valve - 13, first drain valve - 14, first temperature sensor - 15, first pressure sensor - 16, first exhaust valve - 17, second temperature sensor - 18, second pressure sensor - 19, second exhaust valve - 20, second drain valve - 21, third exhaust valve - 22, filter - 23, first electric valve - 24, second electric valve - 25, first flowmeter - 26, first flow sensor - 27, first stop valve - 28, second stop valve - 29, second flow sensor - 30, second flowmeter - 31, third electric valve - 32, third stop valve - 33, fourth stop valve - 34, droplet collector - 35, third flow sensor - 36, third flowmeter - 37, fourth electric valve - 38, third temperature sensor - 39, third pressure sensor - 40, fourth temperature sensor - 41, fourth pressure sensor - 42, fifth temperature sensor - 43, fifth pressure sensor - 44, sixth temperature sensor - 45. Specific embodiments

[0040] Before describing the specific embodiments of the present invention, the overall concept of the present invention is described as follows:

[0041] The present invention is mainly developed for the process of reflood cooling experiments. Most of the currently relatively mature experimental methods are for rod bundles, round tubes, and annular channels. The submergence cooling experiment of a narrow rectangular channel with a highly overheated surface not only needs to achieve transient flow regulation and pressure feedback control, and quickly achieve the matching adjustment of various thermal-hydraulic parameters in a short time, but also needs to achieve high-temperature heating and transient wall temperature measurement in a narrow internal space structure. The development difficulty is relatively high, and the experimental method still has deficiencies.

[0042] Therefore, the present invention proposes a thermal-hydraulic behavior experimental system under the condition of reflood cooling in a narrow rectangular channel. The experimental working fluid is deionized water, and reflood cooling experiments can be carried out on the test section with a narrow rectangular channel structure under different system pressures, working fluid subcooling degrees, heating wall heat flux densities, working fluid flooding speeds, initial heating wall temperatures, and initial liquid levels inside the channel. The present invention is applicable to narrow rectangular channel structures of different sizes, and reflood experiments can be carried out on test sections with single-board double channels, double-board triple channels, and more channel numbers. The present invention can maintain the stability of the system pressure and inlet flow rate during the flooding process, and can ensure that the working fluid subcooling degree, heating wall temperature, and initial liquid level are controllable.

[0043] After introducing the overall concept of the present invention, in order to make the purpose, technical solution and advantages of the present invention clearer and more understandable, the following further details the present invention through specific embodiments in conjunction with the drawings.

[0044] It should be noted that unless otherwise defined, the technical terms or scientific terms used in one or more embodiments of this specification should be the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar terms used in one or more embodiments of this specification do not represent any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative position relationships, and when the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0045] In one embodiment, as Figure 1 shown, a thermal-hydraulic behavior experimental system under the condition of reflood cooling in a narrow rectangular channel is provided, including: a heating water storage tank 1, a nitrogen gas tank 2, a steam tank 3, a canned motor pump 4, a preheating section 5, a first DC power supply 6, a second DC power supply 7, a narrow rectangular channel test section 8, a steam-water separator 9, a pressure stabilizing tank 10, a flow control valve 11, a muffler 12, and a solenoid valve 13.

[0046] The nitrogen gas tank 2 is connected to the heating water storage tank 1. The heating water storage tank 1 stores the medium (experimental water) and provides high-temperature water or steam through heating, serving as the heat source of the system. It is connected to the nitrogen gas tank 2 to maintain the pressure and prevent the medium from vaporizing prematurely. At the same time, it forms a loop with the steam tank 3 for steam recovery or pressure balance.

[0047] The heating water storage tank 1, the steam tank 3, and the flow control valve 11 form a steam circulation loop. The steam tank 3 stores the steam generated by the heating water storage tank 1, balances the system pressure, and serves as a steam buffer or reflux node in the circulation.

[0048] The heating water storage tank 1 is also connected in sequence with the canned motor pump 4, the preheating section 5, and the flow control valve 11 to form a water circulation loop. The canned motor pump 4 drives the circulation of high-temperature and high-pressure fluid to ensure that the medium is transported from the heating water storage tank 1 to the preheating section 5 and the narrow rectangular channel test section 8. The preheating section 5 is provided with a preheating section flowmeter, which can measure the medium flow rate of the preheating section 5 to ensure that the flow rate is accurately controllable. In cooperation with the first DC power supply 6, the medium is preheated to the set temperature.

[0049] Both ends of the preheating section 5 are connected to the first DC power supply 6. The first DC power supply 6 supplies power to the heating elements of the preheating section 5, raises the medium temperature through electric heating, and ensures that the initial temperature required for the experiment is reached before entering the narrow rectangular channel test section 8.

[0050] The flow control valve 11 is also connected to the solenoid valve 13. The flow control valve 11 adjusts the flow rate of each part of the system, controls the medium rate entering the narrow rectangular channel test section 8, and maintains the stability of the experimental conditions.

[0051] The solenoid valve 13 is connected to the narrow rectangular channel test section 8. During the triggering process of the reflooding process, the solenoid valve 8 quickly opens or cuts off the medium passage to control the experimental process.

[0052] Both ends of the narrow rectangular channel test section 8 are connected to the second DC power supply 7. The narrow rectangular channel test section 8 simulates the narrow rectangular channel in actual engineering (such as the fuel plate channel of a nuclear reactor), heats the simulated heat load through the second DC power supply 7, and studies parameters such as heat transfer characteristics, pressure drop, and critical heat flux under reflooding cooling conditions.

[0053] The narrow rectangular channel test section 8 is connected to the steam-water separator 9. The steam-water separator 9 separates the steam-water mixture at the outlet of the narrow rectangular channel test section 8, separates the steam from the liquid water, and ensures that the subsequent components only process a single-phase medium.

[0054] The steam-water separator 9 is connected to the pressure stabilizing tank 10. The pressure stabilizing tank 10 stabilizes the system pressure, absorbs pressure fluctuations, avoids pressure shocks caused by changes in the steam-water mixture flow rate, and ensures the smoothness of the experimental process.

[0055] The pressure stabilizing tank 10 is connected to the muffler 12. The muffler 12 reduces the noise during steam discharge, especially reducing environmental noise pollution during high-pressure steam release.

[0056] The fluid in the heating water storage tank 1 is transported to the preheating section 5 by the canned motor pump 4, heated by the first DC power supply 6, and then enters the narrow rectangular channel test section 8 through the flow control valve 11 and the solenoid valve 13.

[0057] After the narrow rectangular channel test section 8 is heated by the second DC power supply 7, a steam-water mixture is generated, separated by the steam-water separator 9, and the steam enters the pressure stabilizing tank 10 and is discharged through the muffler 12.

[0058] The nitrogen gas tank 2 and the steam tank 3 cooperate to maintain the pressure of the heating water storage tank 1 to ensure the stability of the experimental environment.

[0059] On this basis, as Figure 2 shown, it further includes: the first drain valve 14, the first temperature sensor 15, the first pressure sensor 16, the first exhaust valve 17, the second temperature sensor 18, the second pressure sensor 19, the second exhaust valve 20, the second drain valve 21, the third exhaust valve 22, the filter 23, the first electric valve 24, the second electric valve 25, the first flowmeter 26, the first flow sensor 27, the first stop valve 28, the second stop valve 29, the second flow sensor 30, the second flowmeter 31, the third electric valve 32, the third stop valve 33, the fourth stop valve 34, the droplet collector 35, the third flow sensor 36, the third flowmeter 37, and the fourth electric valve 38.

[0060] The first drain valve 14, the first temperature sensor 15, the first pressure sensor 16, and the first exhaust valve 17 are connected to the heating water storage tank 1.

[0061] The second temperature sensor 18, the second pressure sensor 19, and the second exhaust valve 20 are connected to the steam tank 3.

[0062] The second drain valve 21 is connected to the narrow rectangular channel test section 8.

[0063] The third exhaust valve 22 is connected to the steam-water separator 9.

[0064] The filter 23 is arranged between the heating water storage tank 1 and the canned motor pump 4; the first electric valve 24, the second electric valve 25, the first flowmeter 26, and the first flow sensor 27 are connected in sequence and arranged between the canned motor pump 4 and the preheating section 5; the first stop valve 28 is arranged between the heating water storage tank 1 and the flow control valve 11 to control the flow of the water circulation loop; the second stop valve 29, the second flow sensor 30, the second flowmeter 31, the third electric valve 32, and the third stop valve 33 are connected in sequence and arranged between the flow control valve 11 and the steam tank 3; the fourth stop valve 34 is arranged between the flow control valve 11 and the solenoid valve 13; the droplet collector 35 is connected to the outlet of the steam-water separator 9, between the steam-water separator 9 and the pressure stabilizing tank 10; the third flow sensor 36, the third flowmeter 37, and the fourth electric valve 38 are connected in sequence and arranged between the pressure stabilizing tank 10 and the muffler 12.

[0065] As Figure 3As shown, the system further includes: a third temperature sensor 39 , a third pressure sensor 40 , a fourth temperature sensor 41 , a fourth pressure sensor 42 , a fifth temperature sensor 43 , a fifth pressure sensor 44 , and a sixth temperature sensor 45 .

[0066] The third temperature sensor 39 and the third pressure sensor 40 are connected between the first stop valve 28 and the flow control valve 11; the fourth temperature sensor 41 and the fourth pressure sensor 42 are connected between the fourth stop valve 34 and the solenoid valve 13; the fifth temperature sensor 43 and the fifth pressure sensor 44 are connected between the narrow rectangular channel test section 8 and the steam-water separator 9; the sixth temperature sensor 45 is connected to the narrow rectangular channel test section 8.

[0067] The experimental circuit of the thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel can be divided into four parts as a whole: the experimental body (narrow rectangular channel test section 8), the water supply system (heating water storage tank 1, nitrogen tank 2, shielded pump 4, preheating section 5, first DC power supply 6, flow control valve 11 and steam tank 3), the steam supply system (heating water storage tank 1, nitrogen tank 2, flow control valve 11, steam tank 3, steam-water separator 9, pressure-stabilizing tank 10 and muffler 12) and the outlet auxiliary system (steam-water separator 9, droplet collection tank 35, pressure-stabilizing tank 10 and muffler 12). The heating rod inside the experimental body is heated by the second DC power supply 7 with low voltage and high current. The maximum output current and maximum output voltage of the power supply are determined according to the temperature and resistance of the test section. The temperature, pressure and other measurement signals during the heating process and the formal experiment are recorded and saved in real time by the measurement and control system.

[0068] At the entrance of the experimental body, the feed water system and the steam supply system are respectively connected. One end of the feed water system is connected to the heating water storage tank 1. The cooling water in the heating water storage tank 1 passes through the filter 23, the canned motor pump 4, the electric valves 24, 25, the flowmeter 26, and the solenoid valve 13 in sequence and is connected to the entrance of the experimental body at the other end. When conducting the flooding experiment, it is necessary to accurately control multiple variables such as the heating power, the initial wall temperature, the inlet subcooling degree, and the inlet flow rate. Among them, the feed water system mainly has two functions during the flooding experiment. One is to continuously adjust and match the flow resistance of the water circuit through the regulating valve in the feed water system to adapt to the test section body, so that it can quickly cool the test section body at a preset flow rate after triggering the flooding signal. In addition, another function of the feed water system is that during the heating process of the body, the cooling water also continuously circulates in the feed water system and is heated by the preheating section 5 until the required inlet subcooling degree is reached. The preheating section 5 also uses a high-power first DC power supply 6 as the input. Another branch of the experimental body is connected to the steam supply system. Steam is generated in the steam tank 3, passes through the regulating valve 4, the flowmeter 26, and the solenoid valve 13 and then reaches the entrance of the experimental body; the other end of the steam tank 3 is connected to the pressure buffer tank at the outlet. The steam supply system has two functions. On the one hand, it provides system pressure for the experimental loop when conducting the pressurized experiment. On the other hand, during the heating process of the test section body, to prevent the heating rod from being burned at high temperature due to dry burning, steam is continuously introduced from the bottom.

[0069] Finally, the auxiliary system at the outlet of the test section body is provided with: a steam-water separator 8, a droplet collection tank 35 that can be used to measure the change in liquid holdup during the flooding process, a pressure buffer tank 10 for stabilizing the pressure fluctuations caused by a large amount of steam generated during the experiment; and auxiliary devices such as an electric valve, a vortex flowmeter, and a silencer 12 provided at the outlet discharge. When conducting the flooding experiment, the auxiliary system pipeline at the outlet and the steam pipeline are both wrapped with tracing tapes and controlled by a temperature control system to ensure that the wall superheat degree of the steam pipeline and the outlet pipeline during the experiment is more than 10K above the saturation temperature to prevent the influence of steam condensation on the experimental measurement.

[0070] The data acquisition system of this experiment uses a portable interface module from a general sensor to a computer, realizing data measurement and acquisition under complex transient conditions in the reflooding cooling experiment.

[0071] The thermal-hydraulic behavior experimental system under the reflooding cooling condition in a narrow rectangular channel provided by the present invention has the following advantages:

[0072] 1. The present invention can conduct re-flooding experimental studies on narrow rectangular channels with different thermal parameters, including re-flooding cooling experiments with different system pressures, subcooling degrees of the working fluid, heat flux densities of the heating wall surface, flooding speeds of the working fluid, and initial temperatures of the heating wall surface. It is also applicable to narrow rectangular channel structures of different sizes, and can conduct re-flooding experiments on experimental sections with single-board double channels, double-board triple channels, and more channel numbers.

[0073] 2. The present invention can achieve reasonable control of the initial liquid level in the narrow rectangular channel and conduct re-flooding experiments with different degrees of exposure in the narrow rectangular channel.

[0074] 3. The cooling working fluid of the present invention is deionized water to avoid affecting the insulation performance of the test section and the electric heating section. At the same time, precise control of the working fluid flow is achieved through equipment such as canned motor pumps, flow meters, flow regulating valves, and solenoid valves.

[0075] 4. Both the cooling working fluid (deionized water) and the product working fluid (vapor-liquid mixture) of the present invention are common fluids, and the equipment supply chains such as canned motor pumps, heating water storage tanks, steam-water separators, flow meters, and flow regulating valves are mature. It is convenient and low-cost to construct the system.

[0076] 5. The present invention is based on modular design and has multiple branches, which can adjust the functions of each branch in a timely manner according to experimental requirements. At the same time, all connectors in the loop adopt national standards, which is convenient for damage replacement and adaptive transformation after replacing the test section.

[0077] 6. The present invention connects general sensors to the computer portable interface module through a data acquisition system to achieve data measurement and acquisition under complex transient conditions in the re-flooding cooling experiment. Since full-automatic operation can be realized, it ensures the personal safety of personnel in high-temperature and high-pressure environments.

[0078] It should be noted that some embodiments of the present invention are described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the above embodiments and still achieve the desired results. Additionally, the processes depicted in the figures do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0079] Based on the same inventive concept, corresponding to any of the above-described embodiment systems, the present invention also provides a thermal behavior experimental method under re-flooding cooling conditions in a narrow rectangular channel, including:

[0080] Before testing, debug the thermal behavior experimental system under re-flooding cooling conditions in the narrow rectangular channel, and set the thermal behavior experimental system under re-flooding cooling conditions in the narrow rectangular channel to the initial state;

[0081] Start the canned motor pump, and fill the medium in the heating water storage tank into the loop through the flow control valve. The nitrogen gas tank continuously supplies inert gas to the heating water storage tank; open the solenoid valve, control the water circulation loop to close, and obtain the closed flow data; close the solenoid valve, control the water circulation loop to open, and obtain the open flow data; obtain the flow difference according to the closed flow data and the open flow data; adjust the flow resistance of the water circulation loop to meet the preset requirements;

[0082] In response to the medium submerging the experimental body, drain the cooled medium in the narrow rectangular channel test section, record the flow resistance adjustment data of the water circulation loop, and simultaneously collect the two-phase flow pattern evolution images of the medium;

[0083] Control the medium to circulate in the water circulation loop, heat the preheating section through the first DC power supply to bring the experimental environment to the experimental condition, and obtain the preset inlet subcooling degree;

[0084] Generate steam through the steam tank, control the steam circulation loop to open, introduce the steam into the narrow rectangular channel test section, and heat the narrow rectangular channel test section through the second DC power supply; obtain the wall temperature data of the experimental body;

[0085] In response to the wall temperature data of the experimental body reaching the initial wall temperature of the experimental condition, close the water circulation loop and the steam circulation loop, open the solenoid valve, and trigger the operation of submerging the experimental body with the medium; collect the two-phase flow evolution images of the experimental body;

[0086] The steam-water mixture in the narrow rectangular channel test section enters the steam-water separator for separation. The pressure stabilizing tank absorbs the pressure fluctuations, making the thermal-hydraulic behavior experimental system under the condition of re-flooding and cooling of the narrow rectangular channel in a stable environment, and the muffler eliminates the noise during steam discharge;

[0087] In response to the wall temperature data of the experimental body dropping to the saturation temperature, turn off the canned motor pump, the first DC power supply, the second DC power supply, and the solenoid valve, and drain the cooled medium in the narrow rectangular channel test section.

[0088] On this basis, in response to the wall temperature data of the experimental body dropping to the saturation temperature, turn off the canned motor pump and the second DC power supply, close the solenoid valve, and drain the cooled medium in the narrow rectangular channel test section. After that, it further includes:

[0089] Obtain the integrity data of the thermal-hydraulic behavior experimental system under the condition of re-flooding and cooling of the narrow rectangular channel, and adjust the thermal-hydraulic behavior experimental system under the condition of re-flooding and cooling of the narrow rectangular channel according to the integrity data.

[0090] On this basis, before testing the thermal-hydraulic behavior experimental system under the condition of reflooding in a narrow rectangular channel, the thermal-hydraulic behavior experimental system under the condition of reflooding in a narrow rectangular channel is set to the initial state, including:

[0091] Prepare deionized water and inject the deionized water into the heating water storage tank and the steam tank to reach the preset position;

[0092] Obtain the sealing condition and integrity condition of the thermal-hydraulic behavior experimental system under the condition of reflooding in a narrow rectangular channel;

[0093] Heat the narrow rectangular channel test section and obtain the response of the thermal-hydraulic behavior experimental system under the condition of reflooding in a narrow rectangular channel;

[0094] According to the sealing condition, the integrity condition and the response, conduct pre-test debugging on the thermal-hydraulic behavior experimental system under the condition of reflooding in a narrow rectangular channel, and set the thermal-hydraulic behavior experimental system under the condition of reflooding in a narrow rectangular channel to the initial state.

[0095] Specifically, it includes: preparation work before the experiment.

[0096] Use the deionized water machine to make water and fill the heating water storage tank 1 and the experimental loop, and inject the water level of the steam tank 3 to an appropriate position.

[0097] After checking the insulation condition between the test section (narrow rectangular channel test section 8) and the experimental loop and the on-off condition of the thermocouples, turn on the data acquisition system and observe whether the measurement and control interface is normally displayed and whether the readings of each channel are reasonable.

[0098] Check the sealing performance of the experimental system, turn on the canned motor pump 4, and check whether there is any water leakage at each valve and the end in the loop and the main body. If there is leakage, the thread needs to be tightened again or the corresponding sealing gasket needs to be replaced.

[0099] Use the hand-held controller to check the ranges of the pressure transmitter and the differential pressure transmitter. At the same time, realize zero adjustment of the transmitter by loosening and tightening the drain and air screws and adjusting the screws.

[0100] Fully open the flow control valve 11, adjust the loop flow to the maximum, and close the solenoid valve 13 at the entrance of the test section, so that the cooling water circulates in the water loop. Turn on the switch of the first DC power supply 6 of the preheating section 5, slowly increase the voltage of the first DC power supply 6, heat the medium in the system to around 80 °C, and open the exhaust valves 17, 20, 22 at the high position to discharge the non-condensable gases in the system.

[0101] Turn on the heating equipment of the steam tank 3, and ensure that the steam quantity meets the requirements of the reflooding experiment by monitoring the temperature and pressure changes in the steam tank 3, and then turn off the heater.

[0102] Turn on the second DC power supply 7 of the test section body, confirm that the circuit is conducting, heat the test section at low power, and at the same time check the thermocouple and observe its temperature response.

[0103] After completing the above work, use the single-phase enthalpy rise method to test and estimate the heat dissipation loss of the test section, and determine the heating power required under different experimental conditions.

[0104] Conduct the experiment.

[0105] Turn on the canned motor pump 4 to circulate the cooling water in the water circulation loop of the feed water system. Then open the solenoid valve 13 at the inlet of the test section body, close the return water valve of the water circulation loop, observe the flow rate in the measurement and control interface, and then close the solenoid valve 13 at the inlet of the test section body, open the return water valve, and compare the difference between the flow rate of the coolant through the test section body and the preset flow rate of the working condition. Adjust the flow rate regulating valve 11 of the water circulation loop to match the flow resistance of the water loop and the test section body.

[0106] Repeat the above operations until the cooling water can submerge the experimental body at the preset working condition flow rate. Then record the opening of the flow rate regulating valve (the flow resistance adjustment data of the water circulation loop), and turn off the canned motor pump 4 and open the drain valves 41 and 21 to drain the residual cooling water in the test section body.

[0107] Arrange the high-speed photography system such as the high-speed camera, LED cold light source, and light homogenizing plate, set the image resolution, and at the same time, by continuously adjusting the lighting, the position of the camera, and the focal length of the macro lens, make it possible to observe clear images of the two-phase flow pattern evolution of the medium in the acquisition interface.

[0108] With the recorded valve opening, let the cooling water circulate in the water loop and heat it to the preset inlet subcooling degree of the experimental condition through the preheating section 5.

[0109] Open the valves of the steam circulation loop to let the steam flow into the test section body.

[0110] After considering the heat loss, clarify the actual required power, adjust the heating voltage and current at both ends of the test section body through the measurement and control system, heat the test section at a constant heat flux density, and constantly observe the change of the wall temperature at the position of the reference thermocouple.

[0111] When the wall temperature reaches the initial wall temperature under the operating condition, close the steam inlet valve of the steam circulation loop and the return water valve of the water circulation loop, open the solenoid valve 13 of the cooling water at the inlet of the test section body, and trigger flooding.

[0112] Observe the shooting interface of the high-speed camera. After droplets appear in the picture, click the record trigger button of the camera to record the evolution process of the droplet flow during the flooding process and the vapor-liquid interface evolution process for 40 s during the subsequent development process, and obtain the two-phase flow evolution image of the experimental body.

[0113] After the wall temperature drops to near the saturation temperature, turn off the canned motor pump 4, the first DC power supply 6 and the second DC power supply 7. At the same time, close the inlet valve of the water circulation loop, open the drain valves 14 and 21 to drain all the residual cooling water in the experimental body.

[0114] After the experiment, check whether the tightness and integrity of the experimental loop and the test section body meet the requirements for continuing the experiment. If there are problems, replace the faulty components, and then prepare for the experiment of the next working condition.

[0115] Through the two-phase flow pattern evolution images of the medium, the wall temperature data, and the two-phase flow evolution images of the experimental body, etc., the thermal-hydraulic behavior under the re-flooding cooling condition of the narrow rectangular channel can be studied.

[0116] The method of the above embodiment is used for the thermal-hydraulic behavior experimental system under the corresponding re-flooding cooling condition of the narrow rectangular channel in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be elaborated here.

[0117] Those of ordinary skill in the art should understand that: the discussion of any above embodiment is only exemplary, and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of brevity.

[0118] In the case of elaborating specific details to describe the exemplary embodiments of the present invention, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details or with variations of these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive. Although the present invention has been described in conjunction with specific embodiments of the present invention, many substitutions, modifications, and variations of these embodiments will be obvious to those of ordinary skill in the art based on the foregoing description. For example, other memory architectures

[0119] The embodiments of the present invention are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omission, modification, equivalent substitution, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included within the protection scope of the present invention.

Claims

1. Thermal behavior experimental system under narrow rectangular channel re-flooding cooling conditions, characterized in that: include: Heating water storage tank, nitrogen tank, steam tank, shielded pump, preheating section, first DC power supply, second DC power supply, narrow rectangular channel test section, steam-water separator, pressure regulating tank, flow control valve, muffler and solenoid valve; The nitrogen tank is connected to the heating water storage tank; the heating water storage tank, the steam tank and the flow control valve form a steam circulation loop; the heating water storage tank is also connected to the shielded pump, the preheating section and the flow control valve in sequence to form a water circulation loop; the two ends of the preheating section are connected to the first DC power supply; the flow control valve is also connected to the solenoid valve; the solenoid valve is connected to the narrow rectangular channel test section; the two ends of the narrow rectangular channel test section are connected to the second DC power supply; the narrow rectangular channel test section is connected to the steam-water separator; the steam-water separator is connected to the pressure regulating tank; the pressure regulating tank is connected to the muffler.

2. The thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel according to claim 1 is characterized in that: Also includes: a first drain valve, a first temperature sensor, a first pressure sensor, and a first exhaust valve; The first drain valve, the first temperature sensor, the first pressure sensor and the first exhaust valve are connected to the heating water storage tank.

3. The thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel according to claim 1 is characterized in that: Also includes: a second temperature sensor, a second pressure sensor, and a second exhaust valve; The second temperature sensor, the second pressure sensor, and the second exhaust valve are connected to the steam tank.

4. The thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel according to claim 1 is characterized in that: Also includes: Second drain valve; The second drain valve is connected to the narrow rectangular channel test section.

5. The thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel according to claim 1, characterized in that: Also includes: The third exhaust valve; The third exhaust valve is connected to the steam-water separator.

6. The thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel according to claim 1, characterized in that: Also includes: Filter, first electric valve, second electric valve, first flow meter, first flow sensor, first stop valve, second stop valve, second flow sensor, second flow meter, third electric valve, third stop valve, fourth stop valve, droplet collector, third flow sensor, third flow meter, fourth electric valve; The filter is arranged between the heating water storage tank and the shielded pump; the first electric valve, the second electric valve, the first flow meter and the first flow sensor are connected in sequence and arranged between the shielded pump and the preheating section; the first stop valve is arranged between the heating water storage tank and the flow control valve; the second stop valve, the second flow sensor, the second flow meter, the third electric valve and the third stop valve are connected in sequence and arranged between the flow control valve and the steam tank; the fourth stop valve is arranged between the flow control valve and the solenoid valve; the droplet collector is connected to the outlet of the steam-water separator, between the steam-water separator and the pressure-stabilizing tank; the third flow sensor, the third flow meter and the fourth electric valve are connected in sequence and arranged between the pressure-stabilizing tank and the muffler.

7. The thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel according to claim 6, characterized in that: Also includes: a third temperature sensor, a third pressure sensor, a fourth temperature sensor, a fourth pressure sensor, a fifth temperature sensor, a fifth pressure sensor, and a sixth temperature sensor; The third temperature sensor and the third pressure sensor are connected between the first stop valve and the flow control valve; the fourth temperature sensor and the fourth pressure sensor are connected between the fourth stop valve and the solenoid valve; the fifth temperature sensor and the fifth pressure sensor are connected between the narrow rectangular channel test section and the steam-water separator; the sixth temperature sensor is connected to the narrow rectangular channel test section.

8. Experimental method for thermal behavior of narrow rectangular channel under re-flooding cooling conditions, characterized in that: A thermal behavior experimental system for a narrow rectangular channel under re-flooding cooling conditions as described in any one of claims 1 to 7, comprising: The thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel is debugged before testing, and the thermal behavior experimental system under the condition of re-flooding cooling of the narrow rectangular channel is set to the initial state; Turn on the shielded pump, and fill the circuit with the medium in the heating water storage tank through the flow control valve, and the nitrogen tank continuously supplies inert gas to the heating water storage tank; turn on the solenoid valve, control the water circulation circuit to close, and obtain closed flow data; turn on the solenoid valve, control the water circulation circuit to open, and obtain open flow data; obtain the flow difference according to the closed flow data and the open flow data; adjust the flow resistance of the water circulation circuit to meet the preset requirements; In response to the medium flooding the test body, the cooled medium in the narrow rectangular channel test section is excluded, and the flow resistance adjustment data of the water circulation loop is recorded while collecting the two-phase flow pattern evolution image of the medium; The control medium circulates in the water circulation loop, and the first DC power supply heats the preheating section to make the experimental environment reach the experimental working condition, so as to obtain the preset inlet subcooling degree; Generate steam through a steam tank, control the steam circulation loop to open, pass the steam into the narrow rectangular channel test section, heat the narrow rectangular channel test section through a second DC power supply; and obtain wall temperature data of the experimental body; In response to the wall temperature data of the experimental body reaching the initial wall temperature of the experimental condition, the water circulation loop and the steam circulation loop are closed, the solenoid valve is opened, and the medium submerges the experimental body operation; and an image of the two-phase flow evolution of the experimental body is collected; The steam-water mixture in the narrow rectangular channel test section enters the steam-water separator for separation, and the pressure-surge tank absorbs pressure fluctuations, so that the thermal behavior experimental system under the narrow rectangular channel re-flooding cooling condition is in a stable environment, and the muffler eliminates the noise during steam emission; In response to the wall temperature data of the experimental body decreasing to the saturation temperature, the shielded pump, the first DC power supply, the second DC power supply and the solenoid valve are turned off to remove the cooling medium in the narrow rectangular channel test section.

9. The thermal behavior experimental method of narrow rectangular channel under re-flooding cooling condition according to claim 8, characterized in that: In response to the wall temperature data of the experimental body being reduced to the saturation temperature, the shielded pump and the second DC power supply are turned off, the solenoid valve is closed, and the cooling medium in the narrow rectangular channel test section is discharged, and then the following further comprises: The integrity data of the thermal behavior experimental system under the narrow rectangular channel re-flooding cooling condition is obtained, and the thermal behavior experimental system under the narrow rectangular channel re-flooding cooling condition is adjusted according to the integrity data.

10. The thermal behavior experimental method of a narrow rectangular channel under re-flooding cooling conditions according to claim 8, characterized in that: The pre-test debugging of the thermal behavior experimental system under the narrow rectangular channel re-flooding cooling condition, setting the thermal behavior experimental system under the narrow rectangular channel re-flooding cooling condition to the initial state includes: Prepare deionized water, and inject the deionized water into the heating water storage tank and the steam tank to reach a preset position; Obtain the sealing and integrity of the thermal behavior experimental system under reflooding cooling conditions in narrow rectangular channels; The narrow rectangular channel test section is heated to obtain the response of the thermal behavior experimental system of the narrow rectangular channel under the condition of re-flooding cooling; The thermal behavior experimental system under the narrow rectangular channel re-flooding cooling condition is debugged before testing according to the sealing condition, the integrity condition and the response condition, and the thermal behavior experimental system under the narrow rectangular channel re-flooding cooling condition is set to an initial state.

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