A high-temperature magnetic field environment liquid metal pressure measurement system

Abstract

The application relates to the field of temperature sensors, in particular to a high-temperature magnetic field environment liquid metal pressure measuring system, which comprises a pressure lead pipe with one end as a medium inlet to be communicated with a medium environment to be measured, a separation pressure lead diaphragm and a pressure sensing diaphragm are sequentially arranged in the pressure lead pipe along the direction away from the medium inlet, the separation pressure lead diaphragm, the pressure sensing diaphragm and the pipe wall of the pressure lead pipe enclose a closed pressure lead cavity, and the pipe cavity between the separation pressure lead diaphragm and the medium inlet constitutes a medium cavity for medium flow; the side, away from the pressure lead cavity, of the pressure sensing diaphragm is communicated with a signal output connector through a shielding lead wire to feedback pressure measurement; and a cooling source is arranged outside the pressure lead pipe to exert a cooling effect on the medium cavity. The application can directly measure the pressure of liquid metal with high precision under a strong magnetic field and a high-temperature environment.

Description

Technical Field

[0001] This invention relates to the field of temperature sensors, specifically a liquid metal pressure measurement system in a high-temperature magnetic field environment. Background Technology

[0002] In the design of controlled nuclear fusion reactors, the blanket system plays a crucial role in achieving tritium fuel self-sufficiency, energy conversion, and shielding protection. Its performance directly affects the economics and feasibility of the fusion reactor. Liquid blankets, particularly an integrated scheme using lithium-lead alloys as neutron multipliers, tritium breeders, and coolants, are widely recognized as one of the mainstream technologies. Because lithium-lead alloys are conductive fluids, they generate Lorentz forces under strong magnetic fields, significantly increasing the flow pressure drop and reducing power generation efficiency; this effect is known as the MHD effect. To study the MHD effect, it is necessary to investigate the inlet and outlet pressures and pressure differences of the pipeline under different lead-lithium alloy temperatures and flow rates; therefore, pressure sensors are required for pressure measurement.

[0003] However, the operating temperature of liquid lithium-lead alloys is typically as high as 400°C to 700°C or even higher, while the environment is subject to strong magnetic fields and neutron radiation. Traditional pressure sensors cannot directly measure the pressure of such high-temperature media. Pressure sensors that rely on diaphragms will be damaged and rendered inoperable if they come into contact with such high-temperature media. Furthermore, in strong magnetic fields, the magnetic field can induce electromotive force or magnetoresistive effects, which can increase the measurement error. Therefore, how to directly perform high-precision pressure measurement of liquid metals in strong magnetic fields and high-temperature environments has become an urgent technical problem to be solved. Summary of the Invention

[0004] To avoid and overcome the technical problems existing in the prior art, this invention provides a liquid metal pressure measurement system in a high-temperature magnetic field environment. This invention can directly perform high-precision pressure measurement of liquid metal in a strong magnetic field and high-temperature environment.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A high-temperature magnetic field environment liquid metal pressure measurement system includes a pressure-sensing tube, one end of which serves as a medium inlet and is connected to the medium environment to be measured. An isolation pressure-sensing diaphragm and a pressure-sensing diaphragm are sequentially arranged inside the pressure-sensing tube along the direction away from the medium inlet. The isolation pressure-sensing diaphragm, the pressure-sensing diaphragm, and the tube wall of the pressure-sensing tube enclose a sealed pressure-sensing cavity. The cavity between the isolation pressure-sensing diaphragm and the medium inlet constitutes a medium cavity for medium flow. The side of the pressure-sensing diaphragm away from the pressure-sensing cavity is connected to a signal output connector via a shielded lead for pressure feedback. A cooling source is provided outside the pressure-sensing tube to apply a cooling effect to the medium cavity.

[0006] As a further aspect of the present invention: the cooling source is a cooling pipe coaxially fixed to the outer ring of the pressure tapping pipe, and the inner wall of the cooling pipe and the outer wall of the pressure tapping pipe form an annular cooling cavity. A cooling water inlet and a cooling water outlet are radially provided on the cooling pipe, and the cooling water inlet and the cooling water outlet are arranged opposite to each other on both sides of the pressure tapping pipe.

[0007] As a further embodiment of the present invention: the outer ring of the pressure tapping tube at one end adjacent to the medium inlet is provided with an installation thread, and the pressure tapping tube is fixed to the test environment threaded by the installation thread.

[0008] As a further improvement of the present invention, the length of the installation thread does not exceed 3cm.

[0009] As a further embodiment of the present invention: one end of the cooling pipe is flush with the isolation pressure diaphragm, and the other end is flush with the end face of the mounting thread away from the medium inlet.

[0010] As a further embodiment of the present invention: a heating wire is provided in the cooling cavity, which is coaxially sleeved on the outer ring of the pressure-feeding tube. One end of the heating wire is flush with the isolation pressure-feeding diaphragm, and the other end extends toward the medium inlet.

[0011] As a further aspect of the present invention, the pressure chamber is filled with silicone oil.

[0012] As a further aspect of the present invention: the main material of the pressure tapping tube is 316L stainless steel, and the surface of the 316L stainless steel is provided with an iron-chromium-aluminum oxide dispersion-strengthened alloy.

[0013] As a further aspect of the present invention: the length of the cooling cavity is :

[0014] in, It is the ratio of the working temperature of the liquid metal to the inlet temperature of the medium in the cooling chamber; The thermal conductivity of the medium inside the cooling chamber; r This refers to the inner diameter of the pressure tapping tube. The density of the medium inside the cooling chamber; This refers to the specific heat capacity of the medium inside the cooling chamber. The kinematic viscosity of the liquid metal inside the pressure tapping tube; The thickness of the pressure-sensing tube.

[0015] As a further aspect of the present invention: the actual pressure value obtained by the measuring system after correction is... : ; ;

[0016] in, The pressure value measured by the measurement system; This is a correction factor for the influence of magnetic fields. This is a correction factor for the effects of high temperature. The magnetic field strength at the pressure-sensitive diaphragm; The temperature is the medium temperature.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention constructs a sealed pressure-sensing chamber by setting an isolation pressure-sensing diaphragm and a pressure-sensing diaphragm inside the pressure-sensing tube. This effectively isolates the high-temperature, strong magnetic field, and potentially corrosive liquid metal medium from the electrical signal pressure-sensing element. The isolation pressure-sensing diaphragm directly bears the medium pressure and transmits the pressure losslessly to the pressure-sensing diaphragm through the filling medium in the pressure-sensing chamber. This protects the sensitive element inside the sensor while ensuring the accuracy and reliability of pressure measurement. When the high-temperature liquid metal enters the medium chamber through the medium inlet, the cooling water system is activated to forcibly cool the medium chamber section. Simultaneously, the heating wire operates according to the set temperature, keeping the metal in the medium chamber in a liquid state to prevent solidification and providing dynamic temperature compensation for the isolation pressure-sensing diaphragm. The pressure of the liquid metal in the medium chamber acts on the isolation pressure-sensing diaphragm, causing the diaphragm to undergo slight deformation. This deformation pushes the silicone oil in the pressure-sensing chamber and transmits the pressure to the pressure-sensing diaphragm. The deformation of the pressure-sensing diaphragm is converted into an electrical signal, which is transmitted outward through the shielded lead and signal output connector. This allows for high-precision pressure measurement of liquid metal directly under strong magnetic fields and high temperatures.

[0018] 2. This invention designs a pressure-sensing tube with installation threads and reasonably limits its length, while making the cooling tube flush with the isolation diaphragm and the threaded end face, resulting in a compact structure that facilitates threaded connection and fixation within the limited installation space of the nuclear device, making installation and maintenance convenient.

[0019] 3. This invention determines the length range of the cooling chamber by establishing a formula for calculating the length of the cooling chamber, so that it can effectively cool the medium within the set range. The control of the length range avoids excessive cooling length, which would cause the liquid metal in the medium chamber to solidify, and also avoids insufficient cooling of the liquid metal in the medium chamber, which would damage the magnetic sheet. After introducing the influence of high temperature and magnetic field, the measured pressure value of the system is corrected to improve the measurement accuracy of the measurement system. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention.

[0021] Figure 2 This is a scatter plot of data used in calculating the actual pressure value of this invention.

[0022] In the picture: 1. Pressure tapping tube; 11. Isolating pressure tapping diaphragm; 12. Pressure-sensing diaphragm; 13. Pressure tapping chamber; 14. Shielded lead wire; 15. Signal output connector; 16. Dielectric cavity; 17. Installation thread; 18. Medium inlet; 2. Cooling pipe; 21. Cooling water inlet; 22. Cooling water outlet; 23. Cooling chamber; 24. Heating wire. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1 In this embodiment of the invention, a high-temperature magnetic field environment liquid metal pressure measurement system includes a pressure-introducing tube 1 with openings at both ends. One end of the pressure-introducing tube 1 has an installation thread 17 on its outer side. The tube is screwed into the interface of the environment to be measured through the installation thread 17, so that the medium inlet 18 at its end is connected to the high-temperature liquid metal environment.

[0025] A pressure-sensing diaphragm 11 and a pressure-sensing diaphragm 12 are sequentially arranged along the medium inlet 18 into the cavity. A closed pressure-sensing cavity 13 is formed between the pressure-sensing diaphragm 11 and the pressure-sensing diaphragm 12. The pressure-sensing cavity 13 is filled with silicone oil or other chemically stable pressure-transmitting media with a low coefficient of thermal expansion. The pressure sensed by the pressure-sensing diaphragm 11 can be directly transmitted to the pressure-sensing diaphragm 12.

[0026] The space between the isolation pressure-sensing diaphragm 11 and the medium inlet 18 forms the medium cavity 16. After system installation, high-temperature liquid metal enters the medium cavity 16 through the medium inlet 18 and is blocked by the isolation pressure-sensing diaphragm 11. The side of the pressure-sensing diaphragm 12 furthest from the medium inlet is connected to an external signal output connector 15 via a shielded lead 14. The acquired signal is transmitted to the acquisition card and then sent to the host computer. The shielded lead 14 uses a twisted-pair design with an outer magnetic shielding layer, utilizing the low impedance and high permeability characteristics of ferromagnetic materials to reduce the influence of magnetic fields. The twisted-pair cable consists of two mutually insulated copper wires twisted together in a spiral structure. When an external magnetic field interferes with the twisted-pair cable, the two wires are tightly twisted together, resulting in a very close distance between them, thus canceling out the magnetic fields and reducing magnetic field interference. The outer metal shielding layer of the shielded twisted-pair cable utilizes the reflection, absorption, and skin effect of metal to effectively prevent external electromagnetic interference from entering the cable, while also preventing internal signals from radiating out and interfering with the operation of other equipment. Shielded twisted-pair cables effectively reduce magnetic field interference and improve signal transmission quality and stability through the combined effects of electromagnetic induction cancellation, balanced transmission, skin effect, and shielding layer.

[0027] A cooling pipe 2 is coaxially sleeved on the outside of the pressure-sensing pipe 1. An annular cooling cavity 23 is formed between the inner wall of the cooling pipe 2 and the outer wall of the pressure-sensing pipe 1. The cooling pipe 2 has radially opposite cooling water inlets 21 and cooling water outlets 22. During operation, cooling water flows into the cooling cavity 23 from the cooling water inlet 21, surrounds and washes the outer wall of the pressure-sensing pipe 1, and then flows out from the cooling water outlet 22, continuously carrying away the heat transferred from the medium cavity 16. In this embodiment, one end face of the cooling pipe 2 is flush with the end face of the mounting thread 17, and the other end face of the cooling pipe 2 is flush with the position of the isolation pressure-sensing diaphragm 11. This ensures that the cooling area accurately covers the effective range. The length of the mounting thread 17 is designed not to exceed 3 cm and the thickness is not to exceed 2 mm.

[0028] Inside the cooling chamber 23, a heating wire 24 is also coaxially sleeved. One end of the heating wire 24 is flush with the isolation pressure diaphragm 11. When cooling water is introduced into the cooling pipe 2, through the coordinated control of cooling and heating, if the cooling effect is too good and the temperature of the high-temperature liquid metal near the isolation pressure diaphragm 11 is too low, in order to prevent its temperature from falling below the melting point and solidifying, the heating wire with PID control is started to heat up, so that the temperature at the isolation pressure diaphragm 11 is stabilized at the set value.

[0029] The main material of the pressure tap 1 is preferably 316L stainless steel. Similar to the corrosion behavior of other liquid metals, the corrosion of 316L stainless steel pipes in liquid lithium-lead alloys is also a result of thermodynamic imbalance at the interface between liquid and solid metals. This corrosion manifests in three ways: first, the dissolution of structural material components in the liquid lithium-lead alloy; second, the reaction between impurities (especially oxygen) in the lithium-lead alloy and the material components and intermediate phase products; and third, the easy diffusion and migration of component elements dissolved from the high-temperature part (hot zone) of the system to the low-temperature part (cold zone), which may deposit in the cold zone. In the hot zone, the selective dissolution of material components causes the material to become lighter or thinner; in the cold zone, the deposition of component elements migrating from the hot zone alters the microstructure, electrical resistance, and other properties of the material.

[0030] This application involves coating a 316L stainless steel substrate with an iron-chromium-aluminum oxide dispersion-strengthened alloy coating, which forms a layer approximately 5-10 mm thick on the surface of the iron-chromium-aluminum oxide dispersion-strengthened alloy. μm An oxide film is applied to protect the sensor from corrosion by the liquid metal. Since the substrate material is 316L stainless steel, its material will dissolve and undergo mass migration in the liquid lithium-lead alloy, which is the main cause of material corrosion. However, after applying a dispersion-strengthened iron-chromium-aluminum (FeCrAl) oxide coating to its surface, a 5-10% oxide film is formed. μm The oxide film protects the sensor from corrosion by liquid metal and can withstand the severe corrosion of liquid lead-lithium alloy at 700℃. At 700℃, 316L austenitic stainless steel corrodes severely. When SiC is used to form oxides and other compounds on its surface, the corrosion rate is slower. When an iron-chromium-aluminum oxide dispersion-strengthened alloy coating is used, corrosion is almost non-existent. Since liquid metal lithium-lead cladding is currently one of the main design and research options for fusion reactor claddings internationally, the application of an iron-chromium-aluminum oxide dispersion-strengthened alloy coating can effectively reduce tritium permeability, liquid lithium-lead corrosion, and the MHD effect in the lithium-lead cladding.

[0031] During measurement, the system is secured via mounting thread 17. High-temperature liquid metal enters the medium chamber 16 through the medium inlet 18. The cooling water system is activated to forcibly cool the medium chamber 16. Simultaneously, the heating wire 24 operates according to the set temperature, keeping the metal in the medium chamber liquid and preventing it from solidifying. The pressure of the liquid metal in the medium chamber 16 acts on the isolation pressure-applying diaphragm 11, causing a slight deformation that pushes the silicone oil in the pressure-applying chamber 13 and transmits the pressure to the pressure-sensing diaphragm 12. The deformation of the pressure-sensing diaphragm 12 is converted into an electrical signal, which is transmitted outward via the shielded lead 14 and the signal output connector 15, thus completing the detection.

[0032] To achieve optimal cooling performance, the length of the cooling chamber 23 is... Set within the following range:

[0033] in, This is the ratio of the working temperature of the liquid metal to the inlet temperature of the medium in the cooling chamber 23; The thermal conductivity of the medium inside cooling chamber 23; r This refers to the inner diameter of the pressure tapping tube. The density of the medium inside cooling chamber 23; The specific heat capacity of the medium inside cooling chamber 23; The kinematic viscosity of the liquid metal inside pressure tap 1; The thickness of pressure tube 1.

[0034] The pressure values ​​measured by the system are subject to errors due to the influence of magnetic fields and high temperatures, and need to be corrected using fitting formulas.

[0035] like Figure 2 As shown, the horizontal axis represents the pressure value measured by the measurement system, and the vertical axis represents the pressure error value. Based on the measurement results, values ​​with large error deviations are removed. The remaining error scatter data in the graph are then fitted under different operating conditions to obtain the corrected formula for the actual pressure value. : ; ;

[0036] in, The pressure value measured by the measurement system; This is a correction factor for the influence of magnetic fields. This is a correction factor for the effects of high temperature. The magnetic field strength at pressure-sensitive diaphragm 12; The temperature is the medium temperature.

[0037] The pressure error measured under different magnetic fields and temperatures is shown by the scatter plot of the vertical axis error and the fitting formula. This formula is applicable to use in environments with magnetic fields of 0-5T and temperatures of 0-700℃.

[0038] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0039] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

Claims

1. A liquid metal pressure measurement system in a high-temperature magnetic field environment, characterized in that, The device includes a pressure-sensing tube (1) with one end serving as a medium inlet (18) to communicate with the medium environment to be measured. Inside the pressure-sensing tube (1), an isolation pressure-sensing diaphragm (11) and a pressure-sensing diaphragm (12) are arranged sequentially along the direction away from the medium inlet (18). The isolation pressure-sensing diaphragm (11), the pressure-sensing diaphragm (12), and the tube wall of the pressure-sensing tube (1) enclose a closed pressure-sensing cavity (13). The cavity between the isolation pressure-sensing diaphragm (11) and the medium inlet (18) constitutes a medium cavity (16) for medium flow. The side of the pressure-sensing diaphragm (12) away from the pressure-sensing cavity (13) is connected to the signal output connector (15) through a shielded lead (14) to provide feedback pressure measurement. A cooling source is provided outside the pressure-sensing tube (1) to apply a cooling effect to the medium cavity (16).

2. The liquid metal pressure measurement system in a high-temperature magnetic field environment according to claim 1, characterized in that, The cooling source is a cooling pipe (2) coaxially fixed on the outer ring of the pressure pipe (1). The inner wall of the cooling pipe (2) and the outer wall of the pressure pipe (1) form an annular cooling cavity (23). A cooling water inlet (21) and a cooling water outlet (22) are provided on the cooling pipe (2) radially. The cooling water inlet (21) and the cooling water outlet (22) are arranged opposite to each other on both sides of the pressure pipe (1).

3. The liquid metal pressure measurement system in a high-temperature magnetic field environment according to claim 1, characterized in that, The outer ring of the pressure tapping tube (1) adjacent to the medium inlet (18) is provided with an installation thread (17), and the pressure tapping tube (1) is threaded to the environment to be tested through the installation thread (17).

4. The liquid metal pressure measurement system in a high-temperature magnetic field environment according to claim 3, characterized in that, The length of the installation thread (17) shall not exceed 3cm.

5. The liquid metal pressure measurement system in a high-temperature magnetic field environment according to claim 3, characterized in that, One end of the cooling pipe (2) is flush with the isolation pressure diaphragm (11), and the other end is flush with the end face of the mounting thread (17) away from the medium inlet (18).

6. A liquid metal pressure measurement system in a high-temperature magnetic field environment according to any one of claims 2 to 5, characterized in that, A heating wire (24) is coaxially sleeved on the outer ring of the pressure tube (1) inside the cooling chamber (23). One end of the heating wire (24) is flush with the isolation pressure diaphragm (11), and the other end extends toward the medium inlet (18).

7. A liquid metal pressure measurement system in a high-temperature magnetic field environment according to any one of claims 1 to 5, characterized in that, The pressure chamber (13) is filled with silicone oil.

8. A liquid metal pressure measurement system in a high-temperature magnetic field environment according to any one of claims 1 to 5, characterized in that, The main material of the pressure tap (1) is 316L stainless steel, and the surface of the 316L stainless steel is provided with iron-chromium-aluminum oxide dispersion strengthening alloy.

9. A liquid metal pressure measurement system in a high-temperature magnetic field environment according to any one of claims 1 to 5, characterized in that, The length of the cooling chamber (23) is : in, It is the ratio of the working temperature of the liquid metal to the inlet temperature of the medium in the cooling chamber (23); The thermal conductivity of the medium inside the cooling chamber (23); r This refers to the inner diameter of the pressure tapping tube. The density of the medium inside the cooling chamber (23); The specific heat capacity of the medium inside the cooling chamber (23); The kinematic viscosity of the liquid metal inside the pressure tapping tube (1); The thickness of the pressure tube (1) is given.

10. A liquid metal pressure measurement system in a high-temperature magnetic field environment according to any one of claims 1 to 5, characterized in that, The actual pressure value after correction of the pressure value measured by the measurement system is : ； ； in, The pressure value measured by the measurement system; This is a correction factor for the influence of magnetic fields; This is a correction factor for the effects of high temperature. The magnetic field strength at the pressure-sensitive diaphragm (12); The temperature is the medium temperature.

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