An electromagnetic transducer intended to measure the two-dimensional velocity of conductive fluid flow.

Abstract

To provide an electromagnetic transducer intended to measure two-dimensional velocity components of flow of a conductive fluid.SOLUTION: An electromagnetic transducer 10 intended to measure two-dimensional velocity components of flow of a conductive fluid, the electromagnetic transducer 10 comprises: a cylindrical metal tube 11 forming a core with high magnetic permeability, which tube extends along a central axis Z, including a central portion and two end portions, on either side of the central portion, the two end portions of the cylindrical metal tube 11, each including two protrusions 13.1 to 13.4, opposed to one another relative to the central axis Z and each delimiting a flat surface, parallel to the central axis Z; an electric coil 12 called primary coil and wound around the central portion of the tube; four electric coils 14.1 to 14.4 called receiving coils and each wound around one of the flat surfaces, or four Hall effect sensors each arranged on one of the flat surfaces.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to the field of instrumentation and measurement, particularly in the field of two-dimensional point velocity measurement in conductive fluids, and more specifically to the field of transducers specifically designed for local point velocity measurement of conductive fluids.

[0002] This invention relates to an electromagnetic transducer for measuring the velocity component of a conductive fluid.

[0003] The present invention is generally applicable to all conductive fluids. Examples of such fluids include conductive ionic solutions such as brine, and even liquid metals. Typical examples of such metals are sodium, potassium, lead, lithium, aluminum, copper, iron, zinc, titanium, and their alloys.

[0004] More specifically, the present invention relates to 100 kg·m -3 From 10,000 kg·m -3 This applies to measurements in fluids of the high-density liquid type, which have densities in the ultra-high degree range.

[0005] The present invention is particularly suitable for measuring the velocity of a fluid whose melting temperature range is typically the melting temperature range of a metal that is processed, molded, or used in liquid form, typically from approximately -50°C to over 1,500°C.

[0006] One promising application being considered is measuring heat transfer fluid velocity, particularly in nuclear fission and fusion reactors. [Background technology]

[0007] In many applications, the velocity field of a moving conductive fluid needs to be known.

[0008] This applies in the metal casting industry, where by recognizing the velocity field in the mold and the mold supply circuit, the quality of the parts to be produced can be predicted and defective parts can be limited. In fact, recognizing the flow velocity makes it possible to control and optimize the filling of the mold.

[0009] In the nuclear industry, the velocity field of the metal heat transfer fluid used in the circuits of some nuclear reactors is a major factor from the perspective of the stress on the contacting metal structures. For this reason, recognizing the velocity field is essential.

[0010] The velocity field is also a major factor from the perspective of heat exchange in heat exchangers and in the nuclear fuel of these reactors. Recognizing and analyzing the velocity field in important areas of the reactor (such as heat exchangers, reactor core outlets, pumps, etc.) is also an indicator of correct operation, and by extension, a means of enhancing safety and generally enhancing the ability to monitor these machines.

[0011] Scientific experiments involving large volumes of liquid metal and tests carried out for the purpose of recognizing the flow distribution in heat exchanger headers also require the recognition of the velocity field of the flow involved.

[0012] In the various flow regions mentioned, the flow conditions are three-dimensional. In most cases, the flow is also characterized by those temperature heights that are often several hundred degrees and the density of the fluid used, which can range from several hundred kg·m -3 to several thousand kg·m -3 up to several thousand kg·m.

[0013] Various velocity measurements are known and are used to measure the velocity components of the flow of conductive liquids.

[0014] These techniques include electromagnetic techniques, which are particularly relevant and reliable from the perspective of the resistance of the material to the stress applied to the material by the environment in which the measurement is made. These techniques are even more interesting in the case of highly dense and chemically reactive fluids such as liquid metals.

[0015] The operating principle of an electromagnetic transducer is expressed by Ohm's law in the context of a moving fluid exposed to a magnetic field.

[0016] This equation shows that the conductivity σ of a fluid, combined with the velocity of a moving object u and an external magnetic field B, leads to the development of an electric current (current density J).

[0017]

number

[0018] This can occur even in the absence of an electric field E.

[0019] current density J u Magnetic field B u This is the source of the problem. u This distorts the external magnetic field B.

[0020] For the sake of brevity, it should be noted that the vector symbolized by the letter B, which is magnetic flux density or magnetic induction, will be referred to as the magnetic field throughout this application. It should also be noted that the various formulas provided hereafter are written in a form of semi-permanent approximation where certain quantities involved in Maxwell's equations, such as displacement current, can be ignored.

[0021] Historically, the measurement of a single velocity component of a flow has been performed using electromagnetic transducers, also commonly known by the acronyms FDFM ("Flux Distortion Flow Meter"), ECFM ("Eddy Current Flow Meter"), or PSFM ("Phase Shift Flow Meter").

[0022] A conventional FDFM, generally designated by reference numeral 1, is shown in Figures 1, 2, and 2A. The FDFM is axially symmetric with respect to the central axis Z and typically consists of a core 2, an electric transmitting coil called a primary coil 3, and one or two electric receiving coils called secondary coils 4, 5. The core 2 is formed by a solid rod 20 extending along the central axis Z and solid disks 21 evenly spaced along the central axis Z, with the solid rod integrally connected to the solid disks. The primary coil 3 and secondary coils 4, 5 are wound around the solid rod 20 between two of the solid disks 21.

[0023] An electric current is applied in the primary coil. This current flow, according to the Maxwell-Ampère equations, creates an external magnetic field B in the immediate environment of the primary coil.

[0024]

number

[0025] Here,

[0026]

number

[0027] The primary current is an alternating current, and therefore B is also an alternating current. In this method, B induces a voltage in each of the receiving coils according to the Maxwell-Farade equations.

[0028]

number

[0029] Here,

[0030]

Number

[0031] Also, B causes an induced current density J i not only in the fluid but also in the surrounding conductors exposed to this magnetic field, including the metal of the pipe. Figures 3 and 4 show the development of the current density induced under the action of an external magnetic field in a situation without flow velocity for FDFM with one secondary coil 4 and with two secondary coils 4, 5.

[0032] The current density J i further creates a magnetic field B that distorts the external magnetic field B i Therefore, the field B is not the same, depending on whether the FDFM is surrounded by a conductive fluid.

[0033] In the absence of fluid movement, one or more receiving coils deliver a voltage that is a function of the external magnetic field B and the field B i .

[0034] In the presence of fluid movement, a new current density J u appears and becomes the source of the magnetic field B u . This new field changes B, and B is, so to speak, blown by the flow of the conductive fluid and distorted towards the fluid flow as shown in Figures 5A, 5B, and 6.

[0035] The magnetic flux passing through one or more receiving coils depends on the flow velocity.

[0036] Therefore, one or more receiving coils deliver a voltage that reflects the influence of the magnetic fields B i and B u that distort the external magnetic field B.

[0037] This is demonstrated by digital simulation. Figures 7A and 7B are digital simulations of the magnetic field around the FDFM, with and without the flow velocity of the conductive fluid, respectively.

[0038] By analyzing the voltage emitted by the receiving coil, it is possible to determine the flow velocity of the moving fluid in the region of effect of magnetic field B.

[0039] As shown in Figure 8, when the single receiving coil 4 of the FDFM1 is upstream of the direction of fluid flow, the magnetic flux decreases as the velocity increases (and increases as the velocity decreases). The voltage e1 it supplies decreases by Δe1.

[0040] The voltage e1 supplied by the FDFM is symbolic of the flow velocity (indicated by relative direction by comparing the amplitude of the current signal with the amplitude of the signal without velocity).

[0041] In addition to the above, in the case of an FDFM with two receiving coils, the magnetic flux passing through the downstream receiving coil increases as the fluid velocity increases. Its voltage e2 increases by Δe2.

[0042] Therefore, |Δe2|=|Δe1|.

[0043] Generally, the two receiving coils 4 and 5 of the FDFM are electrically connected in reverse series, as shown in Figure 9.

[0044] In this method, the signal V supplied by the FDFM of the two coils is V = |e2| - |e1| Provided by, where |e x | is voltage e x It is the absolute value or amplitude of [the expression].

[0045] The signal V is proportional to the velocity component of the flow projected onto the axis of rotation of the FDFM.

[0046] In practice, an FDFM with two receiving coils doubles the sensitivity and eliminates the dependence of the FDFM's response on irrelevant factors such as temperature, through the combined use of the voltages output by these two coils. V = (|e2| - |e1|) / (|e2| + |e1|)

[0047] The symbol V indicates the direction of velocity without the need to compare it to the amplitude of the signal without considering the flow velocity.

[0048] Regarding the placement of the FDFM in relation to the fluid flow, the FDFM can be in the flow, that is, it can be positioned along the axis of the tube in the characterized flow [1]. Thus, the FDFM is in the fluid flow surrounding the FDFM.

[0049] In practice, as shown in Figure 10, the internal FDFM1 is generally located at the center of an annular space defined by two concentric tubes T1, T2 through which the fluid F, whose velocity is to be measured, flows.

[0050] Other FDFMs may be outside the flow. Therefore, the coils and cores of the external FDFMs are positioned around the flow of the fluid whose velocity is being measured.

[0051] In practice, an external FDFM is placed around the pipe to measure the velocity of the fluid flow through the pipe.[2]

[0052] When FDFM is used to evaluate the velocity of a fluid flowing through a pipe, it is only possible to measure one velocity component, that is, the component along the pipe's axis, and by extension, the component along the axis of axial symmetry X, whether the FDFM is located inside or outside the pipe. In fact, the pipe guides the fluid flow and provides the fluid in its primary direction.

[0053] Generally speaking, for conventional FDFMs placed in an open medium, that is, conventional FDFMs placed in a large volume of moving conductive fluid, in other words, conventional FDFMs placed in a moving conductive fluid in quantities such that the boundary is far enough away from the FDFM that the velocity vector of the flow in the vicinity of the FDFM is not oriented in the correct direction, it can be seen that the FDFM can only consider a single velocity component of the flow, which is the velocity component projected along the axis of axial symmetry of the FDFM. This is due to the axially symmetric configuration of the FDFM.

[0054] As a result, the conventional use of FDFM in open environments is not definitive enough to characterize some of the velocity components to which FDFM is positioned. Specifically, measuring the velocity of high-density conductive fluids in open environments is problematic in itself.

[0055] Prior art modeling and simulation of FDFM in an open environment, where the velocities of the three-dimensional components are different, demonstrates this.

[0056] The inventors modeled a prior art FDFM and simulated its operation for different velocity stresses surrounding the flow of moving liquid metal (sodium). The analysis uses an orthonormal coordinate system in which the velocities are represented, with X, Y, and Z coordinates.

[0057] Figures 11 and 11A show the magnetic flux density, velocity vector, vertical cross-section Y, and vertical cross-section Z for this prior art FDFM receiving velocity component X.

[0058] Figures 12 and 12A show the magnetic flux density, velocity vector, vertical cross-section X, and vertical cross-section Z for the same prior art FDFM receiving velocity component Y.

[0059] Therefore, it can be seen that when subjected to a velocity component field along x, the prior art FDFM provides the same response signal as when subjected to a single velocity component field along y.

[0060] In conclusion, prior art internal or external FDFM cannot be used to simultaneously measure several components of the multidimensional fluid velocity at a given point location.

[0061] For example, the simultaneous use of several FDFMs, one per velocity component, positioned and oriented to form an orthonormal coordinate system or any other arrangement, is not possible due to the interaction of the magnetic fields of the various FDFMs positioned close to each other.

[0062] Furthermore, transducers are known that can measure several velocity components of a fluid flow at virtually a single point.[3][4][5]

[0063] These include wire or thermofilm probes for aerodynamic measurements. Because these probes are brittle, their use is limited to speeds of a few millimeters per second at best.

[0064] Potential probes can potentially be used to measure local velocity for several velocity components. However, their operation relies on electrical contact between their electrodes and the fluid being characterized. Potential probes are also highly sensitive to oxidation, particularly in liquid metals. Electrical isolation is also required between the electrodes and the metal structure of the probe for use with liquid metals. This limits their use to a lower fluid temperature range than non-contact electromagnetic measurement techniques.

[0065] Therefore, there is no measuring transducer that can evaluate multiple components of the flow velocity of a conductive fluid, which may be of high density, over a range of high velocities and / or at high temperatures.

[0066] Non-contact guided tomography methods have already been tested for measuring multidimensional fluid velocity.

[0067] A publication [6] describes one such method, which currently only allows for the measurement of two velocity components at a point in the radial plane of the fluid. The ability to measure three velocity components has not been demonstrated.

[0068] Patent EP1285277B1 also describes a non-contact guided tomography method.

[0069] The main limitation faced by non-contact guided tomography is that the useful magnetic field observed is only two to five orders of magnitude smaller than the useful magnetic field that needs to be applied.

[0070] Furthermore, these methods also require the external magnetic field to act on a relatively small volume of fluid, typically about 1 m, so that it can propagate through the characterized volume.

[0071] Furthermore, these methods require complex processing algorithms.

[0072] The external magnetic field must pass through the wall material containing the moving fluid, as the equipment performing the measurement method is located on the outside. Therefore, the performance capabilities of the method depend on the properties of the wall material, the thickness of the wall material, and the overall shape of the tomography.

[0073] In summary, prior art FDFMs cannot measure multiple velocity components simultaneously. Prior art FDFMs cannot combine several velocity components in close proximity to each other in order to measure them at a given location due to disturbances that propagate between them.

[0074] Existing measuring transducers cannot evaluate multiple velocity components of conductive fluids, which may be dense, over a range of high velocities and / or at high temperatures.

[0075] Non-contact tomography-based three-dimensional flow measurement methods are comprehensive. These methods utilize instruments positioned outside the fluid volume being characterized. The performance capabilities of these methods depend on the structure containing the fluid volume. The signals from these methods are difficult to process. The size of the fluid volume that these methods can characterize must be limited. Therefore, these methods cannot be implemented in large volumes, such as inside a sodium-cooled reactor vessel.

[0076] Therefore, there is a need to propose a solution for two-dimensional measurement of the flow velocity of conductive fluids, which may be dense, even in large volumes, over a high velocity range, and / or at high temperatures. [Prior art documents] [Patent Documents]

[0077] [Patent Document 1] European Patent No. 1285277 [Overview of the project] [Problems that the invention aims to solve]

[0078] The object of the present invention is to address this requirement at least partially. [Means for solving the problem]

[0079] Therefore, according to the first alternative, the object of the present invention is an electromagnetic transducer intended for measuring the two-dimensional velocity component of the flow of a conductive fluid, - A cylindrical metal tube having a core with high magnetic permeability, extending along a central axis (Z), and comprising a central portion and two end portions on either side of the central portion, wherein the two end portions are opposite each other with respect to the central axis (Z) and each has two projections defining a flat surface parallel to the central axis (Z), - An electrical coil called the primary coil, which is wound around the central part of the tube, - Called a receiving coil, it consists of four electrical coils, each wound around one of the flat surfaces, or four Hall effect sensors, each positioned on one of the flat surfaces. It is an electromagnetic converter equipped with [a specific feature].

[0080] According to the second alternative, the object of the present invention is an electromagnetic transducer intended for measuring the two-dimensional velocity component of the flow of a conductive fluid, - A cylindrical metal tube having a core with high magnetic permeability, extending along a central axis (Z), and comprising a central portion and two end portions on either side of the central portion, wherein the two end portions are opposite each other with respect to the central axis (Z) and each has two projections defining a flat surface parallel to the central axis (Z), - Permanent magnets are placed around the central part of the tube, - Called a receiving coil, it consists of four electrical coils, each wound around one of the flat surfaces, or four Hall effect sensors, each positioned on one of the flat surfaces. It is an electromagnetic converter equipped with [a specific feature].

[0081] Preferably, the core has low conductivity to limit losses induced by variable magnetic induction, i.e., Joule losses associated with the circulation of the induced current, and hysteresis losses.

[0082] Therefore, the present invention primarily involves an electromagnetic transducer that can be operated with alternating current (first variation) or direct current (second variation) for non-contact measurement of two two-dimensional components of a conductive fluid.

[0083] Carefully positioning the receiving coils or Hall effect sensors opposite each other in the diametrical direction allows each component of the local velocity vector, measured by the distortion of the electromagnetic flux, to contribute without disturbance from other contributions.

[0084] The flux strain electromagnetic transducer according to the present invention can measure speeds ranging from several millimeters per second to several meters per second.

[0085] Furthermore, the flux strain electromagnetic transducer according to the present invention typically has a load of 100 kg·m -3 From 10,000 kg·m -3 It is adapted for measuring the rate of conductive liquids at high temperatures, including those with a density up to an ultra-high degree, and / or, typically in the range of the melting temperature for metals that are processed, molded, or used in liquid form. [Effects of the Invention]

[0086] A further object of the present invention is the use of the previously described electromagnetic transducer for measuring the two-dimensional velocity component of the flow of a conductive fluid, such as liquid metal, in a nuclear reactor.

[0087] Ultimately, the electromagnetic converter according to the proposed invention overcomes the limitations identified in prior art devices. - The ability to simultaneously measure two velocity components of a conductive fluid flow within a fluid volume in the immediate vicinity of that flow. - Unlike the prior art FDFM, there is no need to combine electromagnetic transducers with other transducers of the same type, which could potentially invalidate the measurement. - The ability to position electromagnetic transducers within the flow characterized in the area being investigated. - Characterizing the velocity component of a flow, even in a very large volume of fluid. - Processing the signal generated by the electromagnetic transducer, which is far less complex than the reconstruction algorithms required for tomography-based measurement methods. It has many advantages, including [mention specific advantages here].

[0088] Further advantages and features become clearer by referring to the following diagram and reading the detailed description, which is illustrative and not limiting. [Brief explanation of the drawing]

[0089] [Figure 1]This is a schematic side view of a prior art flux strain flowmeter (FDFM) including a (secondary) receiving coil. [Figure 2] This is a schematic side view of a prior art FDFM, including two (secondary) receiving coils. [Figure 2A] Figure 2 is a longitudinal side view. [Figure 3] This figure, taken from Figure 1, shows the expansion of the induced current density under the action of an external magnetic field in the absence of flow velocity. [Figure 4] This figure, taken from Figure 2, shows the development of the induced current density under the action of an external magnetic field in the absence of flow velocity. [Figure 5A] This figure shows the expansion of the induced current density under the action of an external magnetic field when there is a flow velocity, as captured from Figure 1. [Figure 5B] This figure shows the expansion of the induced current density under the action of an external magnetic field when there is a flow velocity, as captured from Figure 1. [Figure 6] This figure, taken from Figure 2, shows the expansion of the induced current density under the action of an external magnetic field when there is a flow velocity. [Figure 7A] This is a diagram of a digital simulation of the magnetic field around an FDFM using prior art, in the absence of a conductive fluid flow velocity. [Figure 7B] This is a diagram of a digital simulation of the magnetic field around an FDFM using prior art, given the flow velocity of a conductive fluid. [Figure 8] This figure, taken from Figure 1, shows the voltage at the terminals of the receiving coil of an FDFM according to prior art. [Figure 9] Figure 2 shows, on one hand, the preferred electrical connection of the receiving coil in an inverse series configuration, and on the other hand, the voltage at the coil terminals and the final voltage measured at the terminals of the prior art FDFM. [Figure 10] This is a reproduction of a prior art FDFM, which is placed inside an embedded tube for measuring the one-dimensional velocity of a flowing fluid F. [Figure 11]This figure shows a digital simulation of a prior art FDFM, where the cross-section at the perpendicular Y receives the velocity component X of the magnetic flux density of the velocity vector. [Figure 11A] This figure shows a digital simulation of a prior art FDFM, where the cross-section at the perpendicular Z receives the velocity component X of the magnetic flux density of the velocity vector. [Figure 12] This figure shows a digital simulation of a prior art FDFM, where the cross-section at the perpendicular Y receives the velocity component Y of the magnetic flux density of the velocity vector. [Figure 12A] This figure shows a digital simulation of a prior art FDFM, where the cross-section at the perpendicular Z receives the velocity component Y of the magnetic flux density of the velocity vector. [Figure 13] This is a schematic perspective view of an alternative electromagnetic converter of the present invention that operates with alternating current and a receiving coil. [Figure 14] Figure 13 is a side view of the electromagnetic transducer along the X-axis. [Figure 15] Figure 13 is a front view of the electromagnetic transducer along the Y-axis. [Figure 16] Figure 13 is a front view of the electromagnetic transducer along the Z-axis. [Figure 17] Figure 13 shows the measurement lines and planes captured by the electromagnetic transducer. [Figure 18] Figure 13 is a schematic perspective view of the longitudinal cross-section of an electromagnetic transducer, showing the arrangement of electrical connection wires for connecting the primary and secondary coils. [Figure 19] This is a schematic perspective view of an alternative electromagnetic converter according to the present invention, including operation with a DC current, a permanent magnet, and a receiving coil. [Figure 20] This figure shows the measurement lines and planes captured by the electromagnetic transducer shown in Figure 19. [Figure 21] Figure 19 is a schematic perspective view of the longitudinal cross-section of an electromagnetic transducer, showing the arrangement of electrical connection wires for connecting the primary and secondary coils. [Modes for carrying out the invention]

[0090] Throughout this application, the terms “upstream” and “downstream” are understood to refer to the direction of fluid flow along the Z-axis around the transducer.

[0091] Through this application, the electromagnetic transducer according to the present invention has three axes that are perpendicular to each other in pairs, that is, - X-axis that defines the transverse direction, - The Y-axis defines the cross-sectional direction, which defines the X-axis and the XY plane. - The Z-axis defines the longitudinal direction, is perpendicular to the XY plane, defines the general direction along which the transducer extends, and defines the axis of rotation of the primary coil. It is determined by its position relative to the XYZ Cartesian coordinate system that forms a trihedron containing it.

[0092] Conventionally, in the remaining parts of this description, the Y-axis is an axis perpendicular to the upper surfaces of the two protrusions on the same measurement line L1. The measurement line is defined as a hypothetical straight line parallel to the Z-axis and passing through the centers of the upper surfaces of the two protrusions at the same perpendicular.

[0093] The same subscript i used to geometrically define the transducer protrusions and coils is used for electromagnetic coupling and signal processing, as will be explained later.

[0094] All protrusions and coils located at the same end of the transducer core have the same odd or even subscript. In the following simulation, the upstream end of the core supports the coils with odd subscripts.

[0095] The voltages generated by the four receiving coils are denoted by e1, e2, e3, and e4, respectively.

[0096] Figures 1 to 12A have already been explained in the prerequisite section. Therefore, they will not be explained in detail thereafter.

[0097] Figures 13 to 17 show an electromagnetic transducer 10 according to the present invention, which is intended to measure two velocity components of a conductive fluid flow.

[0098] The transducer 10 first comprises a cylindrical metal tube 11 that forms an electromagnetic core, the cylindrical metal tube 11 extending along a central axis Z and comprising a central portion 110 and two end portions 111 and 112 on either side of the central portion. Preferably, the length of the central portion 110 is equal to the length of each of the end portions 111 and 112.

[0099] The upstream end portion 111 is provided with two projections 13.1 and 13.3 that are opposite each other with respect to the central axis (Z) and each define a flat surface parallel to the central axis (Z).

[0100] The downstream end portion 112 is oriented opposite to the central axis (Z) and comprises two projections 13.2 and 13.4, each defining a flat surface parallel to the central axis (Z).

[0101] Preferably, all protrusions have the same size and shape.

[0102] Advantageously, each projection has a T-shape when viewed from the front perpendicular to the central axis (Z), and the head of the T-shape is a flat surface.

[0103] The primary electrical coil 12 is wound around the central portion 110 of the tube 11.

[0104] Four electrical receiving coils 14.1, 14.2, 14.3, and 14.4 are each wound around one of the flat surfaces of projections 13.1, 13.2, 13.3, and 13.4.

[0105] Here, the operation of the electromagnetic converter 10 will be described in relation to simulations performed by the inventors.

[0106] As previously defined, the converter 10 has two measurement lines L1 and L2.

[0107] An alternating current is supplied to the primary coil 12.

[0108] This current creates an external magnetic field B with a measurement plane P.

[0109] For simplicity, the magnetic coupling between the primary coil 12 and each of the pairs of coils 14.1 and 14.2 on the measurement plane P, as well as the pairs of coils 14.3 and 14.4 on the measurement plane P, is taken into consideration.

[0110] In the case where the symmetry of B is not changed, and the coupling between the primary coil 12 and the receiving coil or secondary coil is also not changed, B i It exists.

[0111] The fluid in the three-dimensional flow surrounding the transducer 10 is in field B. u This alters the magnetic field that couples the primary coil 12 with the four secondary coils 14.1, 14.2, 14.3, and 14.4. This distortion can be measured thanks to the induced voltage present in the receiving coil.

[0112] The movement of the conductive fluid around the transducer 10, accompanied only by a positive velocity component along the Z-axis, similarly alters the coupling of the coil pair in the measurement plane P.

[0113] In other words, receiving coils 14.1 and 14.3 have induced voltages at their terminals that increase by Δe, while simultaneously, coils 14.2 and 14.4 have induced voltages at their terminals that decrease by Δe.

[0114] The same type of signal processing applied to the coils of prior art FDFMs, as described in the prerequisites, is applicable to the pairs of coils 14.1 and 14.2, and 14.3 and 14.4, for measuring the velocity component z. Therefore, the voltage difference between the coils e1-e2=e3-e4 is a linear function of Z.

[0115] To increase the sensitivity of the transducer 10 to measuring the velocity component along Z, it is possible to determine the sum of these voltage differences (e1-e2)+(e3-e4).

[0116] A flow represented by velocity vectors contained in all planes passing through the Z-axis, and which does not have a single component on this axis, will distort the coupling between the primary coil 12 and each of the groups at the end portions, namely the group of coils 14.1 and 14.2 and the group of coils 14.3 and 14.4.

[0117] Therefore, the flow velocity with a two-dimensional component can be characterized by the converter 10 according to the present invention.

[0118] Generally, the matrix relationships can be defined to reflect the voltages generated by the four receiving coils 14.1-14.4, e1, e2, e3, and e4, as the three-dimensional components (Ux, Uy) of the local velocity vector U.

[0119] This matrix can be represented as follows:

[0120]

number

[0121] therefore, U x =T 11 ·e1+T 12 e2+T 13 e3+T 14 e4 U y =T 21 ·e1+T 22 e2+T 23 e3+T 24 e4

[0122] T ij It exists in the measurement plane i, and consequently the velocity component U x e in the response of the converter to the flow velocity present in the expression j Determine their contributions.

[0123] T ij This depends, firstly, on the characteristics of the transducer material which forms the core 11, the shape of the protrusions 13.1 to 13.4, and the characteristics of the receiving coil, including the number of turns in each of the receiving coils.

[0124] T ij This also reflects the properties of the conductive fluid and the effect of temperature on the surrounding materials.

[0125] Finally, T ij This is also a function of the excitation applied to the converter, that is, a function of the properties and intensity of the magnetic excitation generated by the primary coil.

[0126] As follows, that is, T ij =k t ·k e ·K ij It can be expressed as follows. Here, k t This is a temperature-related influencing factor for various materials that exist. k e This is an influencing factor related to excitation. K ij This reflects the influence of the converter's configuration.

[0127] Therefore, the matrix of the two-dimensional components (Ux, Uy) of the local velocity vector U can be expressed as follows:

[0128]

number

[0129] Typically, the characteristics of prior art FDFMs, as described in the premise section, are established through the results of digital simulations or experiments.

[0130] A publication [7] can be referenced that describes a method for calibrating an external FDFM by providing a known volumetric flow rate Q of liquid metal in a buried tube around which the FDFM is positioned. Given the flow rate Q, the voltages S1 and S2 generated by secondary coils 4 and 5 are measured and utilized so that the response A of the FDFM is determined as follows: A = A1 / A2 Here, A1 = S1 - S2 A2 = S1 + S2 That is the case.

[0131] Response A is related to the volumetric flow rate Q by A = T·Q.

[0132] The coefficient T reflects not only the dimensional and material characteristics of the FDFM, but also the dimensional and material characteristics of the embedded tube, the liquid metal, and its dependence on temperature and response to electrical excitation. There is one value for T for the temperature value associated with the electrical excitation, which is determined by the amplitude and frequency of the electrical excitation.

[0133] The velocity field in the embedded tube that generates the flow rate Q measured by the prior art FDFM includes a velocity parallel to the central axis of the FDFM. Calibration is one-dimensional. A set of coefficients T are determined by parameter testing at a given temperature and excitation.

[0134] The electromagnetic transducer 10 described above can be calibrated using the same method as in [7], but by providing a two-dimensional velocity field.

[0135] During the tests at a fixed temperature and excitation, various velocity fields are continuously given with components Ux and Uy in one or more directions.

[0136] During each test, the voltages e1, e2, e3, and e4 of coils 14.1 to 14.4 can be recorded. The term K of the matrix K is then determined. ij The same number of tests are performed. In this method, the K matrix of the three-dimensional components (Ux, Uy)ij To calculate each of the terms, a linear system of equations can be established and solved.

[0137] The test is weighted by term k t and k e It is parameterized in terms of temperature and excitation so that the effects can be determined.

[0138] Various connecting wires required to supply power to the primary coil 12 and to recover current in the receiving coils 14.1 to 14.4 can be routed inside the cylindrical core 11.

[0139] An example of incorporating these wires is shown in Figure 18, where wire 15 is connected to the primary coil 12, and wires 16.1, 16.2, 16.3, and 16.4 are connected to the receiving coils 14.1, 14.2, 14.3, and 14.4, respectively.

[0140] Instead of coils 14.1, 14.2, 14.3, and 14.4, the Hall effect sensor and the electromagnetic transducer 10 operating with alternating current can also be provided together with the same core 11 as described above. In this embodiment, the Hall effect sensor is fixed directly to a flat surface defined by projections 13.1 to 13.4. Connecting wires 15, 16.1 to 16.4 can be arranged as in the previous embodiment.

[0141] As shown in Figures 19 to 21, instead of the primary coil 12, a permanent magnet 17 with the same core 11 as previously described may also be provided to create a DC-operating electromagnetic converter 10. Connecting wires 16.1 to 16.4 can be arranged as in the previous embodiment.

[0142] Other modifications and improvements can be considered without departing from the scope of the present invention.

[0143] (References) [1]: https: / / www.hzdr.de / db / Cms?pOid=55433&pNid=226 [2]: https: / / ieeexplore.ieee.org / stamp / stamp.jsp?arnumber=9768530 [3]: https: / / www.degruyter.com / document / doi / 10.1515 / HTMP.2000.19.3-4.187 / pdf [4]: https: / / esfr-smart.eu / wp-content / uploads / 2021 / 04 / S35_1_Sven_Eckert_ESFR_SMART_Measuring_Techniques.pdf [5]: https: / / link.springer.com / content / pdf / 10.1007 / 978-1-4020-4833-3_17.pdf?pdf=inline%20link [6]: https: / / iopscience.iop.org / article / 10.1088 / 1757-899X / 228 / 1 / 012023 / pdf [7]: https: / / iopscience.iop.org / article / 10.1088 / 1757-899X / 208 / 1 / 012031 / pdf [Explanation of Symbols]

[0144] 10 Electromagnetic Converters 11. Cylindrical metal tube, core 110 Center part 111 Upstream end part 112 Downstream end part 12 Primary Electric Coil 13.1, 13.2, 13.3, 13.4 Protrusion 14.1, 14.2, 14.3, 14.4 Electrical receiving coil 15, 16.1, 16.2, 16.3, 16.4 connecting lines 17 Permanent Magnets B External magnetic field B i Bu field L1 and L2 measurement lines P Measurement plane Z-axis

Claims

1. An electromagnetic transducer (10) intended to measure the two-dimensional velocity component of the flow of a conductive fluid, A cylindrical metal tube (11) having a core with high magnetic permeability, extending along a central axis (Z), and comprising a central portion and two end portions on either side of the central portion, wherein the two end portions are opposite each other with respect to the central axis (Z) and each has two projections (13.1 to 13.2) defining a flat surface parallel to the central axis (Z), An electric coil (12), called a primary coil, is wound around the central portion of the cylindrical metal tube, An electromagnetic transducer (10) comprising four electric coils (14.1 to 14.4), each called a receiving coil and wound around one of the flat surfaces, or four Hall effect sensors, each positioned on one of the flat surfaces.

2. An electromagnetic transducer (10) intended to measure the two-dimensional velocity component of the flow of a conductive fluid, A cylindrical metal tube (11) having a core with high magnetic permeability, extending along a central axis (Z), and comprising a central portion and two end portions on either side of the central portion, wherein the two end portions are opposite each other with respect to the central axis (Z) and each has two projections (13.1 to 13.2) defining a flat surface parallel to the central axis (Z), A permanent magnet (18) is arranged around the central portion of the cylindrical metal tube and creates a magnetic field having a magnetic flux along the central axis (Z), An electromagnetic transducer (10) comprising four electric coils (14.1 to 14.4), each called a receiving coil and wound around one of the flat surfaces, or four Hall effect sensors, each positioned on one of the flat surfaces.

3. The electromagnetic transducer (10) according to claim 1 or 2, wherein each projection has a T-shape when viewed from the front perpendicular to the central axis (Z), and the head of the T-shape is the flat surface.

4. Use of the electromagnetic transducer according to claim 1 or 2 for measuring the two-dimensional velocity component of the flow of a conductive fluid.

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