阅读说明：本技术 一种用于液态金属局部流速测量的电磁探针及其标定装置 (Electromagnetic probe for measuring local flow velocity of liquid metal and calibration device thereof ) 是由 张大林 陈宇彤 王成龙 田文喜 苏光辉 秋穗正 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种用于液态金属局部流速测量的电磁探针及其标定装置,该电磁探针包括耐高温永磁体、耐高温绝缘基体、耐高温金属电极、漆包电极线、保护套管、耐高温结构胶；其标定装置包括可调速旋转平台、环形容器、电加热器、电磁探针、信号放大系统、信号采集系统、透明护罩和温度计。电磁探针标定装置通过测量电磁探针在不同的液态金属流速下产生的动生电动势,拟合得出液态金属流速和动生电动势之间的关系式,实现电磁探针的标定。经过标定的电磁探针根据标定装置得出的液态金属流速和动生电动势之间的关系进而间接地得出探头处液态金属流速。该套装置可以实现液态金属局部流速的测量。(The invention discloses an electromagnetic probe for measuring the local flow velocity of liquid metal and a calibration device thereof, wherein the electromagnetic probe comprises a high-temperature-resistant permanent magnet, a high-temperature-resistant insulating matrix, a high-temperature-resistant metal electrode, an enamelled electrode wire, a protective sleeve and high-temperature-resistant structural adhesive; the calibration device comprises a speed-adjustable rotary platform, an annular container, an electric heater, an electromagnetic probe, a signal amplification system, a signal acquisition system, a transparent shield and a thermometer. The electromagnetic probe calibration device obtains a relational expression between the liquid metal flow velocity and the motional electromotive force by fitting by measuring the motional electromotive force generated by the electromagnetic probe under different liquid metal flow velocities, so as to realize the calibration of the electromagnetic probe. The calibrated electromagnetic probe indirectly obtains the liquid metal flow velocity at the probe according to the relation between the liquid metal flow velocity and the motional electromotive force obtained by the calibration device. The device can realize the measurement of the local flow velocity of the liquid metal.)

1. An electromagnetic probe for local flow velocity measurement of liquid metal, characterized by: the electromagnetic probe (1) for measuring the local flow velocity of the liquid metal comprises a high-temperature-resistant permanent magnet (1-1) for providing a magnetic field in a high-temperature environment, a high-temperature-resistant insulating base body (1-2) used as a fixing frame, a high-temperature-resistant metal electrode (1-3) used for detecting motional electromotive force, a high-temperature-resistant enameled electrode wire (1-4) used for transmitting motional electromotive force signals, a high-temperature-resistant protective sleeve (1-5) and high-temperature-resistant structural adhesive (1-6) used for bonding and sealing all parts;

the high-temperature-resistant insulating matrix (1-2) is made of a high-temperature-resistant insulating material and is provided with a central hole for placing the high-temperature-resistant permanent magnet (1-1) and two small edge through holes for the high-temperature-resistant metal electrodes (1-3) to penetrate through, the high-temperature-resistant permanent magnet (1-1) is inserted into the central hole of the high-temperature-resistant insulating matrix (1-2), and a gap between the high-temperature-resistant permanent magnet (1-1) and the high-temperature-resistant insulating matrix (1-2) is filled and sealed by high-temperature-resistant structural adhesive (1-6); the high-temperature-resistant metal electrodes (1-3) are provided with two high-temperature-resistant metal electrodes, the two high-temperature-resistant metal electrodes respectively penetrate through the small through holes at the edges of the high-temperature-resistant insulating base bodies (1-2) and extend out of the high-temperature-resistant insulating base bodies (1-2), gaps between the high-temperature-resistant metal electrodes (1-3) and the high-temperature-resistant insulating base bodies (1-2) are filled and sealed through high-temperature-resistant structural adhesives (1-6), and the high-temperature-resistant structural adhesives (1-6) do not cover the head detection ends of the high-temperature-resistant metal electrodes (1-3); the tail terminal of the high-temperature resistant metal electrode (1-3) is connected with a high-temperature resistant enameled electrode wire (1-4); the high-temperature-resistant insulating base body (1-2) is inserted at the bottom of the high-temperature-resistant protective sleeve (1-5), and a gap between the high-temperature-resistant insulating base body (1-2) and the high-temperature-resistant protective sleeve (1-5) is filled and sealed by using high-temperature-resistant structural adhesive (1-6).

2. An electromagnetic probe for local flow rate measurement of liquid metal according to claim 1, characterized in that: the diameter of a central hole of the high-temperature-resistant insulating base body (1-2) is not more than 3mm, the diameters of the two edge small through holes are not more than 1mm, and the two edge small through holes are respectively positioned at two sides of the central hole.

3. An electromagnetic probe for local flow rate measurement of liquid metal according to claim 1, characterized in that: the length of the probe end of the head of the high-temperature resistant metal electrode (1-3) extending out of the high-temperature resistant insulating base body (1-2) is not more than 1 mm.

4. An electromagnetic probe for local flow rate measurement of liquid metal according to claim 1, characterized in that: and high-temperature-resistant insulating paint is coated outside the high-temperature-resistant enameled electrode wire (1-4) connected with the tail wiring terminal of the high-temperature-resistant metal electrode (1-3), so that the high-temperature-resistant enameled electrode wire (1-4) is ensured to be insulated from the outside under the high-temperature condition.

5. An electromagnetic probe for local flow rate measurement of liquid metal according to claim 1, characterized in that: the high-temperature-resistant permanent magnet (1-1) is an axially magnetized cylindrical permanent magnet, and the diameter of the permanent magnet is not more than 2 mm.

6. An electromagnetic probe for local flow rate measurement of liquid metal according to claim 1, characterized in that: the length of the lower end of the high-temperature-resistant insulating base body (1-2) extending out of the high-temperature-resistant protective sleeve (1-5) is not more than 1 mm; the outer diameter of the high-temperature-resistant protective sleeve (1-5) is not more than 10 mm.

7. An electromagnetic probe for local flow rate measurement of liquid metal according to claim 1, characterized in that: the high-temperature-resistant protective sleeve (1-5) is made of a metal material which is good in corrosion resistance, high in structural strength, high-temperature-resistant, non-magnetic and not magnetized, can bear scouring, abrasion and high-temperature environments in the flowing process of liquid metal, and cannot influence the magnetic field of the high-temperature-resistant permanent magnet (1-1).

8. An electromagnetic probe for local flow rate measurement of liquid metal according to claim 1, characterized in that: the high-temperature-resistant structural adhesive (1-6) has the characteristics of insulation, thermal shock resistance, bonding strength retention at high temperature and no cracking of sealing performance.

9. A calibration device for an electromagnetic probe used for measuring the local flow velocity of liquid metal as claimed in any one of claims 1 to 8, characterized in that: the device comprises an electromagnetic probe (1) for measuring the local flow velocity of liquid metal, a transparent shield (2), the liquid metal (3), a thermometer (4), a speed-adjustable rotary platform (5), an electric heater (6), a signal amplification system (7), a data acquisition card (8), a rotary tray (9) and an annular container (10); the electromagnetic probe (1) penetrates through the top of the transparent shield (2) and is fixed on the transparent shield (2); a high-temperature-resistant enameled electrode wire (1-4) at the detection end of the electromagnetic probe (1) is immersed in liquid metal (3) contained in an annular container (10) positioned in the transparent shield (2); the annular container (10) is fixedly connected with the rotary tray (9), is arranged on the speed-adjustable rotary platform (5), and rotates together under the driving of the speed-adjustable rotary platform (5); an electric heater (6) is arranged inside the transparent shield (2) maintaining the temperature inside the transparent shield (2) above the melting point of the liquid metal (3); the temperature in the transparent shield (2) is monitored by a thermometer (4); when the liquid metal (3) flows through the magnetic field of the high-temperature resistant permanent magnet (1-1) at the detection end of the electromagnetic probe, the magnetic induction line is cut to generate motional electromotive force according to the Faraday's law of electromagnetic induction; the dynamic electromotive force generated by the movement of the liquid metal (3) relative to the detection end of the electromagnetic probe (1) is led out by the high-temperature resistant metal electrode (1-3), amplified by the signal amplification system (7) and received and recorded by the data acquisition card (8), so that the measurement of the dynamic electromotive force corresponding to different liquid metal flow rates is completed, a relational expression between the liquid metal flow rate and the generated dynamic electromotive force is obtained by fitting, and the calibration of the electromagnetic probe (1) is realized.

Technical Field

The invention belongs to the field of experimental research on flow characteristics of liquid metal, and particularly relates to an electromagnetic probe for measuring local flow velocity of liquid metal and a calibration device thereof.

Background

A liquid metal cooling reactor refers to a reactor with a new concept which adopts liquid metal as a coolant, has the advantages of high thermal efficiency, low operating pressure, good inherent safety, nuclear fuel proliferation, nuclear waste transmutation and the like, and is one of the most promising reactor types in fourth-generation reactors.

Due to the great difference between the physical and chemical properties of the liquid metal and the traditional light water coolant, research experience obtained based on the light water coolant cannot be directly applied, and experimental research needs to be carried out on the flow properties of the liquid metal in different types of flow channels in the reactor, so that reference is provided for the design and safety analysis of the liquid metal cooled reactor.

The existing liquid flow velocity measuring device is provided with a pitot tube, a laser particle imager, an orifice plate flowmeter, a vortex shedding flowmeter, an electromagnetic flowmeter and the like. However, the above-mentioned devices have more or less some drawbacks when applied to the measurement of the flow rate of liquid metal: the pitot tube has a fine structure, and pressure taking holes are very fine and are easy to block due to local solidification of liquid metal or due to solid impurities in a flow field; most of liquid metal is not transparent, so that the laser particle imager cannot be applied; the orifice plate flowmeter, the vortex street flowmeter and the electromagnetic flowmeter can measure the average flow velocity of a flow cross section, but cannot measure the local flow velocity in a flow channel.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an electromagnetic probe for measuring the local flow velocity of liquid metal and a calibration device thereof, wherein the device is suitable for measuring the local flow velocity of liquid metal in different types of flow channels, can effectively measure the flow velocity distribution of the liquid metal in different types of flow channels, can be used for researching the flow characteristics of the liquid metal, and can also provide reference for the design, safety analysis and verification of a numerical simulation program of a liquid metal cooling reactor.

In order to achieve the purpose, the invention adopts the following technical scheme:

an electromagnetic probe for measuring the local flow velocity of liquid metal is disclosed, wherein the electromagnetic probe 1 for measuring the local flow velocity of liquid metal comprises a high-temperature resistant permanent magnet 1-1 for providing a magnetic field in a high-temperature environment, a high-temperature resistant insulating matrix 1-2 used as a fixed frame, a high-temperature resistant metal electrode 1-3 used for detecting motional electromotive force, a high-temperature resistant enameled electrode wire 1-4 used for transmitting motional electromotive force signals, a high-temperature resistant protective sleeve 1-5 and high-temperature resistant structural adhesive 1-6 used for bonding and sealing all parts;

the high-temperature-resistant insulating matrix 1-2 is made of a high-temperature-resistant insulating material and is provided with a central hole for placing the high-temperature-resistant permanent magnet 1-1 and two small edge through holes for the high-temperature-resistant metal electrodes 1-3 to penetrate through, the high-temperature-resistant permanent magnet 1-1 is inserted into the central hole of the high-temperature-resistant insulating matrix 1-2, and a gap between the high-temperature-resistant permanent magnet 1-1 and the high-temperature-resistant insulating matrix 1-2 is filled and sealed through high-temperature-resistant structural adhesive 1-6; the high-temperature-resistant metal electrodes 1-3 are provided with two high-temperature-resistant metal electrodes which respectively penetrate through the small through holes at the edges of the high-temperature-resistant insulating matrixes 1-2 and extend out of the high-temperature-resistant insulating matrixes 1-2, gaps between the high-temperature-resistant metal electrodes 1-3 and the high-temperature-resistant insulating matrixes 1-2 are filled and sealed through high-temperature-resistant structural adhesives 1-6, and the high-temperature-resistant structural adhesives 1-6 do not cover the head detection ends of the high-temperature-resistant metal electrodes 1-3; the tail terminal of the high-temperature resistant metal electrode 1-3 is connected with a high-temperature resistant enameled electrode wire 1-4; the high-temperature-resistant insulating matrix 1-2 is inserted at the bottom of the high-temperature-resistant protective sleeve 1-5, and a gap between the high-temperature-resistant insulating matrix 1-2 and the high-temperature-resistant protective sleeve 1-5 is filled and sealed by using high-temperature-resistant structural adhesive 1-6.

The diameter of a central hole of the high-temperature-resistant insulating base body 1-2 is not more than 3mm, the diameters of the two edge small through holes are not more than 1mm, and the two edge small through holes are respectively positioned at two sides of the central hole.

The length of the probe end of the head of the high-temperature resistant metal electrode 1-3 extending out of the high-temperature resistant insulating matrix 1-2 is not more than 1 mm.

And high-temperature-resistant insulating paint is coated outside the high-temperature-resistant enameled electrode wire 1-4 connected with the tail wiring terminal of the high-temperature-resistant metal electrode 1-3, so that the high-temperature-resistant enameled electrode wire 1-4 is ensured to be insulated from the outside under the high-temperature condition.

The high-temperature-resistant permanent magnet 1-1 is an axially magnetized cylindrical permanent magnet, and the diameter of the permanent magnet is not more than 2 mm.

The length of the lower end of the high-temperature-resistant insulating base body 1-2 extending out of the high-temperature-resistant protective sleeve 1-5 is not more than 1 mm; the outer diameter of the high-temperature-resistant protective sleeves 1-5 is not more than 10 mm.

The high-temperature-resistant protective sleeve 1-5 is made of a metal material which is good in corrosion resistance, high in structural strength, high-temperature-resistant, non-magnetic and not magnetized, can bear scouring, abrasion and high-temperature environments in the flowing process of liquid metal, and cannot influence the magnetic field of the high-temperature-resistant permanent magnet 1-1.

The high-temperature-resistant structural adhesive 1-6 has the characteristics of insulation, thermal shock resistance, bonding strength retention at high temperature and no cracking of sealing performance.

The calibration device for the electromagnetic probe for measuring the local flow velocity of the liquid metal comprises an electromagnetic probe 1 for measuring the local flow velocity of the liquid metal, a transparent shield 2, the liquid metal 3, a thermometer 4, a speed-adjustable rotating platform 5, an electric heater 6, a signal amplification system 7, a data acquisition card 8, a rotating tray 9 and an annular container 10; the electromagnetic probe 1 penetrates through the top of the transparent shield 2 and is fixed on the transparent shield 2; a high-temperature-resistant enameled electrode wire 1-4 at the detection end of the electromagnetic probe 1 is immersed in liquid metal 3 contained in an annular container 10 positioned in the transparent shield 2; the annular container 10 is fixedly connected with the rotary tray 9, is arranged on the speed-adjustable rotary platform 5 and is driven by the speed-adjustable rotary platform 5 to rotate together; an electric heater 6 is arranged inside the transparent shield 2, maintaining the temperature inside the transparent shield 2 above the melting point of the liquid metal 3; the temperature inside the transparent shield 2 is monitored by a thermometer 4; when the liquid metal 3 flows through the magnetic field of the high-temperature resistant permanent magnet 1-1 at the detection end of the electromagnetic probe, the magnetic induction line is cut to generate motional electromotive force according to the Faraday's law of electromagnetic induction; the motional electromotive force generated by the movement of the liquid metal 3 relative to the detection end of the electromagnetic probe 1 is led out by the high-temperature resistant metal electrodes 1-3, amplified by the signal amplification system 7 and received and recorded by the data acquisition card 8, so that the measurement of the motional electromotive force corresponding to different liquid metal flow rates is completed, a relational expression between the liquid metal flow rate and the generated motional electromotive force is obtained by fitting, and the calibration of the electromagnetic probe 1 is realized.

Compared with the prior art, the invention has the following advantages:

1. the electromagnetic probe for measuring the local flow velocity of the liquid metal has the advantages of simple structure, easy manufacture, low manufacturing cost, high temperature resistance, corrosion resistance and strong reliability, and can be applied to the severe high-temperature and high-corrosivity liquid metal environment.

2. The electromagnetic probe for measuring the local flow velocity of the liquid metal is thin in size, so that the influence on a flow field in the experimental measurement process is small.

3. The electromagnetic probe for measuring the local flow velocity of the liquid metal is developed based on the Faraday's law of electromagnetic induction, so that the applicability is strong. The device is theoretically suitable for measuring the local flow velocity of all transparent/non-transparent conductive liquid after being calibrated by the calibrating device.

4. The electromagnetic probe for measuring the local flow velocity of the liquid metal has the advantages of small size, reliable structure and easy movement, and can flexibly detect the flow velocity of the liquid metal at different positions of the flow channel in the experimental measurement process to obtain the liquid metal velocity field.

In conclusion, the device can realize the measurement of the local flow velocity of the liquid metal in different flow channels, the experimental device has the advantages of simple structure, easy realization, low manufacturing cost and strong reliability, and effectively widens the experimental research method and thought of the flow characteristic of the liquid metal.

Drawings

FIG. 1a is a front view of an electromagnetic probe for local flow rate measurement of liquid metal in accordance with the present invention;

FIG. 1b is a cross-sectional view corresponding to A-A in FIG. 1 a.

Fig. 2 is a schematic structural diagram of a calibration device of an electromagnetic probe for measuring a local flow velocity of liquid metal according to the present invention.

FIG. 3a is a schematic diagram of an experimental system for measuring the local flow velocity of the liquid metal in a round pipe by using an electromagnetic probe for measuring the local flow velocity of the liquid metal according to the present invention;

fig. 3B is a cross-sectional view corresponding to B-B in fig. 3 a.

Detailed Description

The invention is described in detail below with reference to the drawings and examples of the specification:

as shown in fig. 1a and 1b, an electromagnetic probe 1 for measuring the local flow velocity of liquid metal according to the present invention includes a high temperature resistant permanent magnet 1-1 for providing a magnetic field in a high temperature environment, a high temperature resistant insulating substrate 1-2 for a fixed frame, a high temperature resistant metal electrode 1-3 for detecting motional electromotive force, a high temperature resistant enameled electrode wire 1-4 for transmitting motional electromotive force, a high temperature resistant protective sleeve 1-5, and a high temperature resistant structural adhesive 1-6 for bonding and sealing each component.

The high-temperature resistant insulating matrix 1-2 is made of high-temperature resistant aluminum oxide ceramic insulating materials, is provided with a central hole for placing the high-temperature resistant permanent magnet 1-1, and is provided with small edge through holes for the high-temperature resistant metal electrodes 1-3 to penetrate through at two sides. The central aperture of the high-temperature-resistant insulating substrate 1-2 is 2.1mm, and the apertures of the small through holes at the two side edges are 0.9 mm. The high-temperature resistant permanent magnet 1-1 is inserted into a central hole of the high-temperature resistant insulating matrix 1-2; the two high-temperature resistant metal electrodes 1-3 are respectively inserted into the small through holes at the two side edges of the high-temperature resistant insulating substrate 1-2 and extend out of the high-temperature resistant insulating substrate 1-2. The gap between the high-temperature resistant permanent magnet 1-1 and the high-temperature resistant insulating matrix 1-2 is filled and sealed by high-temperature resistant structural adhesive 1-6; gaps between the high-temperature-resistant metal electrodes 1-3 and the high-temperature-resistant insulating matrixes 1-2 are filled and sealed through high-temperature-resistant structural adhesives 1-6, and the high-temperature-resistant structural adhesives 1-6 do not cover the head detection ends of the high-temperature-resistant metal electrodes 1-3. The tail part of the high-temperature resistant metal electrode is connected with a high-temperature resistant enameled electrode wire 1-4.

The high-temperature resistant metal electrodes 1-3 are made of high-temperature resistant tungsten steel rods with the diameter of 0.8mm and the length of 40 mm.

The length of the probe end of the head of the high-temperature resistant metal electrode 1-3 extending out of the high-temperature resistant insulating matrix 1-2 is 0.5 mm.

The high-temperature resistant enameled electrode wire 1-4 connected with the tail wiring terminal of the high-temperature resistant metal electrode 1-3 is selectedWith a cross-sectional area of 0.3mm²The copper core enameled electrode wire is characterized in that the insulating paint coated outside the electrode wire is made of Teflon insulating paint which can resist the temperature of more than 250 ℃ for a long time.

The high-temperature-resistant permanent magnet 1-1 is an axially magnetized cylindrical permanent magnet made of samarium cobalt, has the diameter of 2.0mm and the Curie point of 850 ℃, and can work for a long time at 350 ℃ without demagnetization.

The high-temperature resistant insulating matrix 1-2 is inserted at the bottom of the high-temperature resistant protective sleeve 1-5, and the high-temperature resistant protective sleeve is a nonmagnetic austenitic stainless steel thin-wall sleeve with the inner diameter of 5.5mm and the wall thickness of 0.3 mm. And gaps between the high-temperature-resistant insulating base bodies 1-2 and the high-temperature-resistant protective sleeves 1-5 are filled and sealed by high-temperature-resistant structural adhesive 1-6. The length of the lower end of the high-temperature-resistant insulating base body 1-2 extending out of the high-temperature-resistant protective sleeve 1-5 is 0.5 mm.

The JL-528 type high-temperature-resistant epoxy resin AB adhesive is selected as the high-temperature-resistant structural adhesive 1-6, can maintain the bonding strength at a high temperature of 300 ℃, and has good insulativity.

As shown in FIG. 2, the calibration device for the electromagnetic probe for measuring the local flow velocity of the liquid metal comprises an electromagnetic probe 1 for measuring the local flow velocity of the liquid metal, a transparent shield 2, a liquid metal 3, a thermometer 4, a speed-adjustable rotary platform 5, an electric heater 6, a signal amplification system 7, a signal acquisition system 8, a rotary tray 9 and an annular container 10.

As a preferred embodiment of the invention, the transparent shield 2 is a cylindrical shield made of transparent acrylic plate and containing a top cover, the liquid metal 3 is made of low melting point wood alloy with the melting point of about 70 ℃, the thermometer 4 is made of a metal spring type thermometer, the adjustable-speed rotating platform 5 is an MK-ET150J digital display adjustable-speed industrial rotating platform, the electric heater 6 adopts a silicon rubber constant temperature electric heating belt, the signal amplification system 7 is a cascade amplification system consisting of a TLC-2652 type chopping self-stabilizing zero amplifier with the voltage amplification factor of 100 times and an AD620 type differential amplifier with the voltage amplification factor of 500 times, the signal acquisition system 8 is an ART-USB3202N type high-frequency voltage acquisition card, the rotary tray 9 is a stainless steel circular tray with the diameter of 280mm, and the annular container 10 is an annular container made of PEEK resin with high temperature resistance of 300 ℃.

The electromagnetic probe 1 penetrates through the top of the transparent shield 2 and is fixed on the top cover of the transparent shield 2; a high-temperature-resistant enameled electrode wire 1-4 at the detection end of the electromagnetic probe 1 is immersed in liquid metal 3 contained in an annular container 10 positioned in the transparent shield 2; the annular container 10 is fixedly connected with the rotary tray 9, is arranged on the speed-adjustable rotary platform 5 and is driven by the speed-adjustable rotary platform 5 to rotate together; an electric heater 6 is arranged inside the transparent shield 2, maintaining the temperature of the transparent shield 2 above the melting point of the liquid metal 3; the temperature inside the transparent shield 2 is monitored by a thermometer 4; the liquid metal 3 moves relative to the detection end of the electromagnetic probe 1 to cause motional electromotive force to be led out from the high-temperature resistant metal electrodes 1-3, then the motional electromotive force is amplified by the signal amplification system 7 and then received and recorded by the data acquisition card 8, the motional electromotive force generated by different liquid metal flow rates is measured, a relational expression between the liquid metal flow rate and the generated motional electromotive force is obtained through fitting, and the calibration of the electromagnetic probe 1 is realized.

As shown in fig. 3a and fig. 3b, when the electromagnetic probe for measuring the local flow velocity of the liquid metal of the present invention is applied to the local flow velocity measurement of the liquid metal in the circular tube, the electromagnetic probe includes a low melting point wood's alloy liquid metal 100 flowing in the circular tube, a circular tube wall 101, a high temperature resistant flexible sealing gasket 102, an electromagnetic probe 1 calibrated to measure the local flow velocity of the liquid metal, a signal amplification system 7, a data acquisition card 8, and a computer 103 connected to the data acquisition card 8.

As a preferred embodiment of the present invention, the circular tube wall 101 is made of nonmagnetic austenitic stainless steel, the high temperature resistant flexible sealing washer 102 is made of high temperature resistant graphite packing, the electromagnetic probe 1 for measuring the local flow velocity of the liquid metal is calibrated by the calibration device provided by the present invention, and the signal amplification system 7 and the data acquisition card 8 adopt the same set of devices used when the electromagnetic probe 1 is calibrated.

The pipe wall 101 of the circular pipe is provided with a through hole for the electromagnetic probe 1 to pass through, the high-temperature-resistant sealing washer 102 is filled in the through hole, and the detection end of the electromagnetic probe 1 passes through the high-temperature-resistant sealing washer 102 and is immersed in the flow field of the low-melting-point wood's alloy liquid metal 100. The motional electromotive force caused by the flow of the low melting point wood metal alloy liquid metal 100 is led out through the electromagnetic probe 1, then is amplified by the signal amplification system 7 and then is received and recorded by the data acquisition card 8, and according to the measured motional electromotive force, the local flow velocity of the low melting point wood alloy liquid metal 100 at the detection end of the electromagnetic probe can be obtained by combining the relation between the liquid metal flow velocity and the motional electromotive force obtained when the electromagnetic probe 1 is calibrated by using the calibration device of the invention.

The foregoing is illustrative of the present invention in further detail in connection with specific preferred embodiments only, and the present invention is not to be considered as limited thereto, and it will be apparent to those skilled in the art that various changes and modifications can be made to the above-described embodiments within the spirit and scope of the present invention as hereinafter claimed.