Plate-shaped fuel assembly coolant channel two-phase three-dimensional full flow field measurement system and method

Abstract

The invention provides a two-phase three-dimensional full flow field measurement system and method for a coolant channel of a plate-shaped fuel assembly. The system comprises a water tank, a centrifugal pump, a regulating valve, a turbine flowmeter, a nuclear magnetic resonance spectrometer, an experimental channel, a gas-water separator, a gas compressor, a gas tank, a pressure release valve, a gas flowmeter and data acquisition equipment. Liquid is driven by the centrifugal pump to enter the experiment channel from the water tank through the hose. Gas is driven by the gas compressor to enter the experimental channel through a hose via a hole channel in the side wall of the experimental channel; the adjusting valve and the turbine flowmeter are installed on the downstream of the centrifugal pump, and the pressure release valve and the gas flowmeter are installed on the downstream of the gas tank and used for adjusting and monitoring the gas-liquid proportion; the experimental channel is arranged on a nuclear magnetic resonance spectrometer, and a three-dimensional flow field in the plate-shaped fuel assembly is obtained through scanning of the nuclear magnetic resonance spectrometer; the gas-water mixture flows out of the experiment channel and then flows into the gas-water separator for separation, air is discharged to the outside, and liquid is conveyed and flows back to the water tank through the hose. According to the system, the measurement accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of two-phase flow field measurement, and particularly to a three-dimensional full flow field measurement system and method for a coolant channel of a plate-shaped fuel assembly. Background Art

[0002] Due to the development of nuclear power, while paying attention to the safety of nuclear power, the economy of nuclear power has also become one of the important criteria for measuring nuclear power. In terms of economy, there are many limitations in building large reactor nuclear power plants to provide power, and the miniaturization of equipment is very important. The coolant channels of the plate-shaped fuel assembly are narrow rectangular channels. The size effect makes the narrow rectangular channels have certain enhanced heat transfer. The low temperature of the fuel core in the plate-shaped fuel assembly and the deep burnup are also its advantages, and it is widely used in the cores of integral reactors and experimental reactors. This feature greatly reduces the core volume compared with that of conventional nuclear power plants to meet the needs of power supply on islands or mobile devices. At the same time, the plate-shaped fuel assembly has broad application prospects in offshore nuclear power platforms and nuclear power ship reactors. Studying the three-dimensional flow characteristics of the coolant channels of the plate-shaped fuel assembly has important scientific significance and engineering application value for exploring the mechanism of fuel plate deformation accidents and optimizing engineering design in research nuclear reactors. Two-phase flow phenomena will occur in the coolant channels of the plate-shaped fuel assembly due to the entry of bubbles or endothermic boiling, which is a common flow phenomenon in actual situations. Therefore, it is crucial to study the two-phase flow phenomena in the coolant channels of the plate-shaped fuel assembly.

[0003] In previous studies, most used high-speed photography to study two-phase flow: photographing two-phase flow flowing in a glass box with good light transmittance, and then distinguishing the flow type and studying the flow situation based on the pictures. This method is simple and fast, but due to the requirement of this technology for the light transmittance of the experimental model, this technology can only measure the flow field in a local area of a single narrow rectangular channel, and cannot study the differences and mutual influences of the flow field characteristics between multiple channels in the fuel assembly. At the same time, the photos can only obtain the surface flow field distribution and cannot obtain the internal flow field data. Another method in use is the ray method, which measures by the attenuation degree of rays when passing through different density media. It is also a non-contact measurement method that will not affect the internal flow field and temperature field, and can obtain data such as gas distribution and flow pattern in the flow field, but it is difficult to accurately obtain the internal flow field. Another method is the particle dynamic analysis technology (PDA), which combines laser measurement and particle dynamic analysis, and can measure the particle velocity, geometric shape and concentration at a certain point on a plane in the two-phase flow field, and is mostly used in experimental studies related to multiphase flow and jet. However, the multiphase flow studied by PDA currently only conducts in a local area of a simple transparent channel. For the three-dimensional full flow field measurement of multiphase flow in the complex coolant channels of fuel assemblies, because of the great difficulty, no relevant reports have been found in the published literature.

[0004] In summary, the prior art requires the light transmittance of the channel, making it difficult to measure for the complex configuration of the coolant channel of the plate-type fuel assembly, and the measurement accuracy is relatively low. Summary of the Invention

[0005] In view of this, the present invention provides a two-phase three-dimensional full flow field measurement system and method for the coolant channel of a plate-shaped fuel assembly to solve the above problems.

[0006] The present invention provides a two-phase three-dimensional full flow field measurement system for the coolant channel of a plate-shaped fuel assembly, including: a water tank, a centrifugal pump, a regulating valve, a turbine flowmeter, a partition wall, a nuclear magnetic resonance instrument, an experimental channel, a gas-liquid separator, a compressor, a gas tank, a pressure relief valve, a gas flowmeter, and a data acquisition device; the water tank is used for storing liquid, and the gas tank is used for storing gas; the centrifugal pump is connected to the water tank through a hose and is used to drive the liquid in the water tank. Under the drive of the centrifugal pump, the liquid enters the experimental channel from the water tank through the hose; the compressor is connected to the gas tank through a hose and is used to drive the gas in the gas tank. Under the drive of the compressor, the gas enters the experimental channel through the hole in the side wall of the experimental channel through the hose; the regulating valve and the turbine flowmeter are installed downstream of the centrifugal pump, and the pressure relief valve and the gas flowmeter are installed downstream of the gas tank for adjusting and monitoring the gas-liquid ratio; the experimental channel is arranged on the nuclear magnetic resonance instrument, and the three-dimensional flow field inside the plate-shaped fuel assembly is obtained by scanning with the nuclear magnetic resonance instrument; the gas-liquid separator is connected to the experimental channel through a hose and is used for separating air and water. After the gas-liquid mixture flows out of the experimental channel, it flows into the gas-liquid separator for separation. The gas-liquid separator discharges the air into the outside, and the liquid is transported back to the water tank through the hose.

[0007] In another implementation manner of the present invention, the experimental channel includes an expansion section, a development section, an experimental section, and a contraction section, and each section is connected by using a flange, a gasket, and a nylon bolt.

[0008] In another implementation manner of the present invention, the inside of the experimental section is divided into non-communicating narrow rectangular channels; the fluid enters the plate-shaped channel of the experimental section from the straight channel of the development section, then converges into the contraction section, and finally the three-dimensional flow field inside the plate-shaped fuel assembly is obtained by scanning.

[0009] In another implementation manner of the present invention, there are holes on the side wall of the experimental section, and the gas enters a closed single narrow rectangular channel through the holes.

[0010] In another implementation manner of the present invention, the narrow rectangular channel is processed and made of plexiglass or resin material.

[0011] In another aspect of the present invention, a method for measuring the two-phase three-dimensional full flow field of the coolant channel of a plate-shaped fuel assembly is provided, which is applied to the two-phase three-dimensional full flow field measurement system of the coolant channel of the plate-shaped fuel assembly as described in any one of the above. The method includes: driving a liquid by a centrifugal pump to make the liquid enter the experimental channel from a water tank through a hose; driving a gas by a compressor to make the gas enter the experimental channel through a hole in the side wall of the experimental channel through the hose; adjusting and monitoring the gas-liquid ratio through a regulating valve, a turbine flowmeter, a pressure relief valve, and a gas flowmeter; setting the experimental channel on a nuclear magnetic resonance instrument, and scanning through the nuclear magnetic resonance instrument to obtain the three-dimensional flow field inside the plate-shaped fuel assembly; separating the gas-water mixture flowing out of the experimental channel through a gas-water separator, discharging the air into the outside, and transporting the liquid back to the water tank through the hose.

[0012] In the two-phase three-dimensional full flow field measurement system of the coolant channel of the plate-shaped fuel assembly of the present invention, models of the coolant channels of plate-shaped fuel assemblies with different geometric structures can be realized, and the two-phase flow full flow field distribution inside the coolant channels of the plate-shaped fuel assemblies can be obtained safely, efficiently, and accurately under different working conditions, providing support for studying the two-phase flow characteristics and cooling mechanisms inside the coolant channels of the plate-shaped fuel assemblies; at the same time, it meets the non-ferromagnetic requirements of the nuclear magnetic resonance instrument, ensures good sealing of the channels, improves the measurement accuracy, and provides reliable comparison data for numerical research. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. By reading the detailed description of the following embodiments, the advantages and benefits in the solutions will become clear to those skilled in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. In the drawings:

[0014] Figure 1 It is a schematic diagram of the framework of a two-phase three-dimensional full flow field measurement system for the coolant channel of a plate-shaped fuel assembly according to an embodiment of the present invention.

[0015] Figure 2 It is a schematic diagram of the structure of the experimental channel according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS:

[0017] Water tank (1), centrifugal pump (2), regulating valve (3), turbine flowmeter (4), isolation wall (5), nuclear magnetic resonance instrument (6), expansion section (7), development section (8), experimental section (9), contraction section (10), gas-water separator (11), compressor (12), gas tank (13), pressure relief valve (14), gas flowmeter (15), data acquisition device (16). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the following will clearly and detailedly describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art shall fall within the scope protected by the embodiments of the present invention.

[0019] Figure 1 Schematic diagram of the framework of a two-phase three-dimensional full flow field measurement system for the coolant channel of a plate-shaped fuel assembly provided by an embodiment of the present invention, as Figure 1 shown, the present embodiment mainly includes the following steps:

[0020] Water tank (1), centrifugal pump (2), regulating valve (3), turbine flowmeter (4), isolation wall (5), nuclear magnetic resonance instrument (6), experimental channel, gas-liquid separator (11), compressor (12), gas tank (13), pressure relief valve (14), gas flowmeter (15), data acquisition device (16).

[0021] The water tank (1) is used to store liquid, and the gas tank (13) is used to store gas.

[0022] The centrifugal pump (2) is connected to the water tank (1) through a hose and is used to drive the liquid in the water tank (1). Under the drive of the centrifugal pump (2), the liquid enters the experimental channel from the water tank (1) through the hose.

[0023] The compressor (12) is connected to the gas tank (13) through a hose and is used to drive the gas in the gas tank (13). Under the drive of the compressor (12), the gas enters the experimental channel through the hose via the pore channels on the side wall of the experimental channel.

[0024] The regulating valve (3) and the turbine flowmeter (4) are installed downstream of the centrifugal pump (2), and the pressure relief valve (14) and the gas flowmeter (15) are installed downstream of the gas tank (13), and are used to adjust and monitor the gas-liquid ratio.

[0025] The experimental channel is arranged on the nuclear magnetic resonance instrument (6), and the three-dimensional flow field inside the plate-shaped fuel assembly is obtained by scanning with the nuclear magnetic resonance instrument (6).

[0026] The gas-liquid separator (11) is connected to the experimental channel through a hose and is used for the separation of air and water. After the gas-liquid mixture flows out of the experimental channel, it flows into the gas-liquid separator (11) for separation. The gas-liquid separator (11) discharges the air into the outside, and the liquid is transported back to the water tank (1) through the hose.

[0027] Exemplarily, in the two-phase flow system, the liquid working medium is deionized water, and the gas working medium is air mixed with sulfur hexafluoride. The reason for using sulfur hexafluoride (SF6) as the nuclear magnetic resonance active gas is its good magnetic resonance characteristics. Compared with other gases, it has the following advantages: the fluorine nucleus of sulfur hexafluoride has a gyromagnetic ratio second only to that of the hydrogen nucleus; in addition, sulfur hexafluoride molecules have a low molecular self-diffusion coefficient, which reduces the signal attenuation and image blurring caused by gas diffusion during image acquisition. These advantages make the velocity signal obtained using sulfur hexafluoride as the nuclear magnetic resonance active gas have a higher signal-to-noise ratio.

[0028] Nuclear magnetic resonance velocity measurement mainly utilizes the electromagnetic characteristics of hydrogen (H) nuclei in water and fluorine (F) nuclei in sulfur hexafluoride. The atomic nuclei undergo Larmor precession in an external static strong magnetic field (B0 is the magnetic field strength), and the precession frequency ω = γB0 (γ is the gyromagnetic ratio of the atomic nucleus, which is only determined by the type of atomic nucleus). A large number of atomic nuclei in the working medium undergo Larmor precession to generate a net magnetization vector M0. At this time, a radio frequency (RF) signal with a frequency of ω is briefly applied, and nuclear magnetic resonance occurs. M0 changes to M. As the RF action ends, the net magnetization vector gradually recovers from M to M0. During this process, the receiving coil collects the nuclear magnetic resonance (MR) signal that changes with time. The frequencies and phases of the MR signals at different spatial positions are different, so as to achieve spatial positioning. In addition, the flow velocities at different positions are related to the phases of the MR signals. For example, in the x-direction gradient magnetic field along the x-direction with a macroscopic velocity the atomic nuclei moving, their local Larmor frequency ω L can be expressed as follows:

[0029]

[0030] where is the position at the initial time t0.

[0031] Therefore, the phase of the atomic nucleus precession changes with the gradient magnetic field and the macroscopic motion velocity of the atomic nucleus, and can be expressed as follows:

[0032]

[0033] where Φ0 is the initial phase.

[0034] By applying a positive and negative bidirectional frequency gradient magnetic field (and flow encoding), combined with the above formula, velocity measurement can be achieved.

[0035] During the scanning process, the application of the magnetic field and radio frequency signal, and the collection of the signal are all realized by the nuclear magnetic resonance instrument.

[0036] Magnetic resonance venography (MRV) technology is non-invasive and does not require light to enter, making it very suitable for measuring complex channels. At the same time, most of the existing technologies can only obtain direct data such as gas distribution and flow pattern or the velocity at a specific point, while MRV technology can obtain the velocity distribution in all directions of the entire three-dimensional flow field. Thus, MRV can accurately analyze the full-field three-dimensional flow field in the fuel rod bundle channel, which is crucial for studying the characteristics of full-field heat transfer enhancement and its flow mechanism, and can quickly and accurately locate the three-dimensional detailed flow characteristics near the local extreme heat transfer region, laying a foundation for the mechanism study of enhanced heat transfer in the channel.

[0037] Specifically, to meet the strong magnetic field environment of the nuclear magnetic resonance imaging equipment, only the experimental channel made of non-metallic materials enters the nuclear magnetic resonance imaging room, and the rest of the equipment is placed outside the nuclear magnetic room. A centrifugal pump and a compressor are used to drive liquids and gases respectively. In the built water circulation system, the fluid is driven by the centrifugal pump and is transported from the water tank through a hose into the experimental channel; at the same time, the air mixed with sulfur hexafluoride in the gas storage tank also enters the experimental channel through the holes on the side wall of the experimental channel through a plastic pipe under the drive of the compressor. After the gas-liquid mixture flows out of the experimental channel, it flows into the gas-liquid separator, where air and water are separated. The air is discharged to the outside, and the water is transported back to the water tank through a hose. The pipelines of the centrifugal pump in contact with water are all made of 304 stainless steel to avoid introducing rust during the experiment and affecting the test. In addition, a regulating valve and a flow meter are installed downstream of the centrifugal pump, and a pressure reducing valve and a gas flow meter are installed downstream of the gas storage tank to adjust and monitor the gas-liquid ratio, enabling quantitative measurement of the gas-liquid two-phase full-space velocity distribution in the coolant channel of the plate-shaped fuel assembly. All components are connected by PVC hoses.

[0038] In the two-phase three-dimensional full-flow field measurement system of the plate-shaped fuel assembly coolant channel of the present invention, models of plate-shaped fuel assembly coolant channels with different geometric structures can be realized, and the two-phase flow full-flow field distribution inside the plate-shaped fuel assembly coolant channel can be obtained safely, efficiently, and accurately under different working conditions, providing support for studying the two-phase flow characteristics and cooling mechanism inside the plate-shaped fuel assembly coolant channel; at the same time, it meets the non-ferrous requirement of the nuclear magnetic resonance instrument and ensures good sealing of the channel, improving the measurement accuracy and providing reliable comparison data for numerical research.

[0039] In another implementation manner of the present invention, the experimental channel includes a diffuser section (7), a developing section (8), an experimental section (9), and a contraction section (10), and each section is connected by using a flange in cooperation with a rubber gasket and nylon bolts.

[0040] Exemplarily, such as Figure 2As shown in the figure, the experimental channel includes a divergent section (7), a developing section (8), an experimental section (9), and a convergent section (10). It is placed on the scanning platform of the nuclear magnetic resonance instrument. Each section is connected by nylon bolts through the flange plates at both ends. The experimental section (9) is 700 mm long and is provided with 8 fuel plates with a width of 2.2 cm, and the plate spacing is 4.2 cm, which proportionally simulates the standard type of plate fuel assembly specified by the International Atomic Energy Agency (IAEA).

[0041] In another implementation manner of the present invention, the interior of the experimental section is divided into non - communicating narrow rectangular channels; the fluid enters the plate - shaped channels of the experimental section (9) from the straight channel of the developing section (8), then converges into the convergent section (10), and finally the three - dimensional flow field inside the plate fuel assembly is scanned and obtained.

[0042] Exemplarily, the plate fuel assembly is composed of plate - shaped fuels and narrow rectangular coolant channels, and has the characteristics of compact structure and strong impact resistance due to the small plate spacing.

[0043] In another implementation manner of the present invention, there are pore channels provided on the side walls of the experimental section (9), and gas enters a certain closed single narrow rectangular channel through the pore channels.

[0044] Exemplarily, holes are drilled on the side walls of the experimental section of the experimental channel, and gas enters a certain closed single narrow rectangular channel through the pore channels.

[0045] In another implementation manner of the present invention, the narrow rectangular channels are processed and made of plexiglass or resin materials.

[0046] Exemplarily, each channel is processed from plexiglass or resin materials, and the components are connected by flanges with gaskets and nylon bolts to ensure the requirements of channel sealing and non - ferromagnetic properties.

[0047] Preferably, plugs can be placed at different positions in the cooling channels at different positions in the experimental section to simulate the flow field under the fuel plate deformation accident of the plate fuel assembly.

[0048] Preferably, the velocity measurement section can be replaced with plate fuel assemblies with different geometric parameters (for example: different fuel plate thicknesses, different coolant channel widths, different numbers of fuel plates and coolant channels).

[0049] Preferably, a handle device can be added at the inlet and a streamlined contraction can be set at the outlet channel, so as to be closer to the plate fuel assembly of an actual research - type nuclear reactor.

[0050] On the other hand of the present invention, there is provided a method for measuring the two - phase three - dimensional full flow field of the coolant channels of a plate fuel assembly, which is applied to the two - phase three - dimensional full flow field measurement system of the coolant channels of a plate fuel assembly as described in any one of the above, and includes:

[0051] Drive a liquid through a centrifugal pump so that the liquid enters the experimental channel from a water tank through a hose.

[0052] Drive a gas through a compressor so that the gas enters the experimental channel through a hole in the side wall of the experimental channel via a hose.

[0053] Regulate and monitor the gas-liquid ratio through a regulating valve, a turbine flowmeter, a pressure relief valve and a gas flowmeter.

[0054] Set the experimental channel on a nuclear magnetic resonance instrument, and obtain the three-dimensional flow field inside the plate-shaped fuel assembly through scanning by the nuclear magnetic resonance instrument.

[0055] Separate the gas-liquid mixture flowing out of the experimental channel through a gas-liquid separator, discharge the air to the outside, and transport the liquid back to the water tank through a hose.

[0056] Exemplarily, due to the large velocity difference between the gas and the liquid, it is difficult to obtain the velocity distribution of the two-phase flow in the internal channel through a single experiment. Therefore, it is necessary to measure twice. Measure the velocity distributions of the gas and the liquid separately at different resolutions, and obtain the velocity distribution of the two-phase flow through post-processing. Obtain the velocity data of the single liquid phase for the first time and the velocity of the single gas phase for the second time. In post-processing, adjust the velocity cloud maps of the two phases to the same velocity range and merge and superimpose them together, so as to obtain the velocity cloud map of the two-phase flow.

[0057] In the method for measuring the three-dimensional full flow field of the coolant channel of the plate-shaped fuel assembly of the present invention, a coolant channel model of the plate-shaped fuel assembly with different geometric structures can be realized, and the full flow field distribution of the two-phase flow inside the coolant channel of the plate-shaped fuel assembly can be obtained safely, efficiently and accurately under different working conditions, providing support for studying the two-phase flow characteristics and cooling mechanism inside the coolant channel of the plate-shaped fuel assembly; at the same time, meeting the non-ferrous requirement of the nuclear magnetic resonance instrument and ensuring good sealing of the channel, improving the measurement accuracy, and providing reliable comparison data for numerical research.

[0058] The present invention also provides an electronic device, which may include: a processor, a memory, and a communication bus and a communication interface.

[0059] Among them:

[0060] The processor, the memory, and the communication interface complete communication with each other through the communication bus.

[0061] The communication interface is used for communicating with other electronic devices or servers.

[0062] A processor for executing a program, specifically capable of executing the steps of any of the above-described methods for measuring the two-phase three-dimensional full flow field of the coolant channels of the plate-shaped fuel assembly in the embodiments.

[0063] Specifically, the program may include program code, and the program code includes computer operation instructions.

[0064] The processor may be a central processing unit (CPU), or a specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. One or more processors included in the intelligent device may be of the same type of processor, such as one or more CPUs; or may be of different types of processors, such as one or more CPUs and one or more ASICs.

[0065] A memory for storing the program. The memory may include high-speed RAM memory and may also include non-volatile memory, such as at least one disk memory.

[0066] The program is specifically configured to cause the processor to execute the steps for implementing any of the methods for measuring the two-phase three-dimensional full flow field of the coolant channels of the plate-shaped fuel assembly described in the embodiments. For the specific implementation of each step in the program, reference may be made to the steps and corresponding descriptions in the units of any of the above-described methods for measuring the two-phase three-dimensional full flow field of the coolant channels of the plate-shaped fuel assembly, and details are not repeated here. Those skilled in the art can clearly understand that for the sake of convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding process descriptions in the foregoing method embodiments.

[0067] The present invention also provides a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the methods of the embodiments of the present application.

[0068] The method according to an embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk, or magneto-optical disk), or can be implemented as computer code originally stored in a remote recording medium or a non-transitory machine-readable medium and downloaded through a network and to be stored in a local recording medium, so that the method described herein can be stored on such a software process on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component (such as a RAM, a ROM, a flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0069] Thus far, specific embodiments of the present invention have been described. Other embodiments are within the scope of the appended claims. In some cases, the acts recited in the claims can be performed in a different order and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing can be advantageous.

[0070] It should be noted that all directional indications (such as up, down, left, right, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0071] In the description of the present invention, the terms "first" and "second" are only used for convenience in describing different components or names, and cannot be understood as indicating or implying an order relationship, relative importance, or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0072] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

[0073] It should be noted that although the specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, it should not be construed as a limitation on the protection scope of the present invention. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative work still fall within the protection scope of the present invention.

[0074] The examples of the embodiments of the present invention are intended to briefly illustrate the technical features of the embodiments of the present invention, so that those skilled in the art can intuitively understand the technical features of the embodiments of the present invention, and do not serve as an improper limitation on the embodiments of the present invention.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A two-phase three-dimensional full flow field measurement system for coolant channels of a plate-shaped fuel assembly, characterized in that Including: Water tank, centrifugal pump, regulating valve, turbine flowmeter, isolation wall, nuclear magnetic resonance (NMR) instrument, experimental channel, air-water separator, compressor, gas tank, pressure relief valve, gas flowmeter, data acquisition device; The water tank is used for storing liquid, and the gas tank is used for storing gas; The centrifugal pump is connected to the water tank through a hose and is used to drive the liquid in the water tank. Under the drive of the centrifugal pump, the liquid enters the experimental channel from the water tank through the hose; The compressor is connected to the gas tank through a hose and is used to drive the gas in the gas tank. Under the drive of the compressor, the gas enters the experimental channel through the pore channels on the side wall of the experimental channel through the hose; The regulating valve and the turbine flowmeter are installed downstream of the centrifugal pump, and the pressure relief valve and the gas flowmeter are installed downstream of the gas tank, which are used to adjust and monitor the gas-liquid ratio; The experimental channel is arranged on the NMR instrument, and the three-dimensional flow field inside the plate-shaped fuel assembly is obtained by scanning with the NMR instrument; The air-water separator is connected to the experimental channel through a hose and is used for separating air and water. After the air-water mixture flows out of the experimental channel, it flows into the air-water separator for separation. The air-water separator discharges the air into the outside, and the liquid is transported back to the water tank through the hose.

2. The system according to claim 1, wherein The experimental channel includes a divergent section, a developing section, an experimental section and a convergent section, and each section is connected by using a flange, a gasket and nylon bolts.

3. The system according to claim 2, wherein The inside of the experimental section is divided into non-communicating narrow rectangular channels; The fluid enters the plate-shaped channel of the experimental section from the straight channel of the developing section, then converges into the convergent section, and finally the three-dimensional flow field inside the plate-shaped fuel assembly is obtained by scanning.

4. The system according to claim 3, wherein Pore channels are arranged on the side wall of the experimental section, and the gas enters a closed single narrow rectangular channel through the pore channels.

5. The system according to claim 2, wherein The narrow rectangular channel is processed and made of plexiglass or resin material.

6. A method for measuring the two-phase three-dimensional full flow field of a coolant channel in a plate-shaped fuel assembly, which is applied to the two-phase three-dimensional full flow field measurement system of the coolant channel in the plate-shaped fuel assembly according to any one of claims 1-5, characterized in that, Including: Driving the liquid by a centrifugal pump to make the liquid enter the experimental channel from the water tank through a hose; Driving the gas by a compressor to make the gas enter the experimental channel through the pore channels on the side wall of the experimental channel through a hose; Adjusting and monitoring the gas-liquid ratio by a regulating valve, a turbine flowmeter, a pressure relief valve and a gas flowmeter; Arranging the experimental channel on the NMR instrument and obtaining the three-dimensional flow field inside the plate-shaped fuel assembly by scanning with the NMR instrument; Separating the air-water mixture flowing out of the experimental channel by an air-water separator, discharging the air into the outside, and transporting the liquid back to the water tank through a hose.

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