A race-track shaped conductive fluid flow rate control device with a rectangular cross-section

Abstract

The application discloses a rectangular-section runway-shaped conductive fluid flow rate control device, which is composed of an I-shaped support and a C-shaped support; a symmetrical magnetic circuit is arranged in the device and passes through the straight section of the runway-shaped conductive fluid; permanent magnets are respectively adsorbed on the inner side surfaces of the two symmetrical C-shaped supports; the fluid channel is in the shape of a runway, the cross section of the channel is rectangular, and the channel is filled with conductive fluid; the fluid channel does not contact the permanent magnets, and the upper and lower walls of the straight section of the channel are respectively provided with first, third and second, fourth electrodes and are in contact with the conductive fluid. The application controls the flow rate of the conductive fluid in the channel by controlling the size of the input electric signal, and detects the flow rate in the channel by the electromotive force generated by the cutting of the magnetic induction lines when the conductive fluid flows.

Description

Technical Field

[0001] This invention relates to the field of magnetohydrodynamics, and more specifically, to a racetrack-shaped conductive fluid velocity control device with a rectangular cross-section. Background Technology

[0002] In recent years, the application of conductive fluid flow rate control has become increasingly important in medical microfluidic actuation and calibration of magnetohydrodynamic sensors. For example, disease diagnosis and biochemical analysis require accurate pumping of body fluids and drug solutions. In sensor measurement, controlling the flow rate of conductive fluids can improve the measurement accuracy and frequency range of magnetohydrodynamic sensors, eliminate some mechanical and assembly errors, and can be widely applied to micro-acceleration measurement and precise attitude control of aircraft. Therefore, conductive fluid actuation and flow rate control technology is crucial for both the development of efficient biomedical equipment and advanced micro-measurement technologies.

[0003] Currently, commonly used fluid velocity control technologies include differential pressure drive technology and current drive technology. The former has problems such as low control accuracy and high noise. Moreover, this type of velocity control method is mostly open structure, with low accuracy and easy to be interfered with by external factors. Direct current drive technology has high power consumption and low efficiency. In contrast, the velocity control system of a general circular channel cross section usually has problems such as easy generation of eddies and uneven velocity. Summary of the Invention

[0004] The present invention addresses the shortcomings of the prior art by proposing a rectangular cross-section racetrack-shaped conductive fluid flow rate control device, which aims to achieve flow rate control and detection of conductive fluids and overcome problems such as low control accuracy, uneven flow rate, and high noise.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] The present invention provides a rectangular cross-section racetrack-shaped conductive fluid flow rate control device, characterized in that two C-shaped supports are symmetrically arranged on the crossbeam of a metal I-shaped support, and the two C-shaped supports are respectively fixed on the upper left and right sides of the metal I-shaped support.

[0007] A set of permanent magnets is installed on the inner walls of the channels on both sides of the two C-shaped supports, and they are numbered sequentially from left to right. The left magnetic circuit is formed by permanent magnets No. 1 and No. 2, and the right magnetic circuit is formed by permanent magnets No. 3 and No. 4. The south pole face of permanent magnet No. 1 is in contact with the left inner surface of the left C-shaped support, and the north pole face of permanent magnet No. 2 is in contact with the right inner surface of the left C-shaped support. The starting point of the left magnetic circuit is the north pole face of permanent magnet No. 1, and the ending point is the south pole face of permanent magnet No. 2. The south pole face of permanent magnet No. 3 is in contact with the left inner surface of the right C-shaped support, and the north pole face of permanent magnet No. 4 is in contact with the right inner surface of the right C-shaped support. The starting point of the right magnetic circuit is the north pole face of permanent magnet No. 3, and the ending point is the south pole face of permanent magnet No. 4.

[0008] A racetrack-shaped conductive fluid channel consisting of two bends and two straight segments is formed between two sets of permanent magnets; the longitudinal section of the racetrack-shaped conductive fluid channel is rectangular, and the racetrack-shaped conductive fluid channel is filled with conductive liquid.

[0009] The inner wall of the racetrack-shaped conductive fluid channel is in contact with permanent magnet No. 2 and permanent magnet No. 3 respectively, and the outer wall of the racetrack-shaped conductive fluid channel is spaced at a certain distance from permanent magnet No. 1 and permanent magnet No. 4 respectively. The distance between the inner and outer walls of the channel is used as the width of the racetrack-shaped conductive fluid channel.

[0010] Above the racetrack-shaped conductive fluid channel is the upper wall of the channel, on which a first electrode and a third electrode are disposed; and the first and third electrodes are respectively disposed on two straight segments of the upper wall of the channel.

[0011] Below the racetrack-shaped conductive fluid channel is the lower wall of the channel, on which a second electrode and a fourth electrode are disposed; and the second and fourth electrodes are disposed on a straight section of the lower wall of the channel.

[0012] The rectangular cross-section racetrack-shaped conductive fluid flow rate control device of the present invention is characterized in that: the left magnetic circuit and the right magnetic circuit pass perpendicularly through the two straight segments of the racetrack-shaped conductive fluid channel, and the magnetic field distribution is uniform and symmetrical.

[0013] Furthermore, the first and second electrodes input voltage / current signals to provide initial signals for controlling the flow rate, and work together with the left magnetic circuit to cause the conductive liquid to flow; the flowing conductive fluid generates motional electromotive force in the right magnetic circuit, and outputs potential signals through the third and fourth electrodes to detect the result of the flow rate control.

[0014] Furthermore, the flow direction of the fluid in the left and right magnetic circuits and the racetrack-shaped conductive fluid channel is perpendicular to the direction of the input voltage / current.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. This invention innovates the application of magnetohydrodynamics (MHD) to drive conductive fluids, differing from traditional differential pressure drive and current drive technologies. This invention controls the flow rate of conductive fluids through a non-contact electromagnetic drive method. This control technology has advantages such as low power consumption, low noise, high reliability, high sensitivity, low eddy current interference, and long lifespan; and solves many problems of current domestic conductive fluid flow rate control technologies.

[0017] 2. This invention is based on the principle of electromagnetic induction, using a conductive fluid material that combines good fluidity and excellent conductivity. It utilizes the relative motion between the fluid's flow and the channel walls and magnetic field region to cut magnetic field lines and generate a motional electromotive force, driving the fluid flow. Unlike traditional fluid-driven technologies, it drives closed-loop fluid flow through current and magnetic fields, thus containing no moving mechanical structures, eliminating mechanical wear, and offering advantages such as high reliability and long lifespan.

[0018] 3. The fluid channel used in this invention is a racetrack-shaped structure with a rectangular cross-section. Its external support forms a recessed gap, which stably fixes the magnetic circuit, permanent magnet, and channel sidewall in the overall structure within the gap. The structure is robust and reliable. Furthermore, the axes of symmetry of the support base, internal magnetic circuit, permanent magnet, and channel wall are all perpendicular to the axis of the sensitive axis of the magnetohydrodynamic vibration sensor, greatly reducing the influence of cross-axis vibration. Therefore, it can work in complex vibration environments. Moreover, the structure is compact, with only the inner wall of the channel in contact with the support, greatly reducing the error caused by magnetic field leakage.

[0019] 4. This invention mainly utilizes the fluidity and conductivity of fluids, and achieves control over the flow rate of conductive fluids by using the electromagnetic induction principle of generating electromotive force by cutting magnetic field lines during the fluid's movement. It does not contain complex circuits with components such as capacitors, thus eliminating errors caused by electroinduction.

[0020] 5. The fluid channel cross-section of the present invention is a rectangle with a width on the order of mm. The magnetic circuit design follows the principle of minimum magnetic reluctance. Compared with the traditional circular cross-section channel that is prone to generating eddy currents, it is less affected by eddy currents. When the fluid is driven, the internal flow velocity distribution is symmetrical and uniform. The device can obtain significant fluid motion with a small current / voltage input.

[0021] 6. The method used in this invention is to control the external current / voltage intensity to control the fluid flow rate. The correspondence between the voltage / current magnitude and the flow rate is determined by the preliminary simulation work. The flow rate acquisition and analysis are completed by the acquisition circuit and filtering. The overall operation is simple, the flow rate control results are accurate and can be displayed intuitively, so it can be flexibly applied to actual production and life scenarios. Attached Figure Description

[0022] Figure 1 This is a structural diagram of the racetrack-shaped conductive fluid velocity control device with a rectangular cross-section according to the present invention;

[0023] Figure 2 This is an internal structural diagram of the rectangular cross-section racetrack-shaped conductive fluid velocity control device of the present invention.

[0024] Figure 3 This is a cross-sectional view of the fluid channel of the racetrack-shaped conductive fluid velocity control device with a rectangular cross section according to the present invention;

[0025] Numbered in the diagram: 1. Metal I-shaped support; 2. Right C-shaped support; 3. Permanent magnet No. 3; 4. Outer wall of the channel; 5. Inner wall of the channel; 6. Upper wall of the channel; 7. Lower wall of the channel; 8. First electrode; 9. Third electrode; 10. Permanent magnet No. 1; 11. Left C-shaped support; 12. Second electrode; 13. Fourth electrode; 14. Conductive fluid channel; 15. Left magnetic circuit; 16. Right magnetic circuit; 17. Permanent magnet No. 2; 18. Permanent magnet No. 4. Detailed Implementation

[0026] In this embodiment, a rectangular cross-section racetrack-shaped conductive fluid flow rate control device controls the flow rate of the conductive fluid within the channel by controlling the magnitude of the input electrical signal. The flow rate is detected by the electromotive force generated when the conductive fluid cuts magnetic field lines. Specifically, the device's external design is as follows: Figure 1 As shown, a metal I-beam bracket 1, assembled from three rectangular copper plates, is designed for ease of fabrication. Two C-shaped brackets are symmetrically positioned on its crossbeam, fixed to the upper left and right sides of the metal I-beam bracket 1 respectively. Internal grooves are formed to secure the various components in contact with them. The internal support is made of indium steel, a soft magnetic material with high saturation magnetic flux density, to prevent interference between the internal and external magnetic fields of the structure. Figure 2 , Figure 3 As shown, the groove contains, from left to right, the following:

[0027] Four permanent magnets, made of rectangular neodymium iron boron (NdFeB) that provides a uniform and strong magnetic field, are used. Permanent magnets 1 and 2 form the left magnetic circuit 15, and permanent magnets 3 and 4 form the right magnetic circuit 16. The south pole of permanent magnet 10 and the north pole of permanent magnet 2 17 are in contact with the left and right inner surfaces of the left C-shaped support 11, respectively. The start and end points of the left magnetic circuit 15 are from the north pole of permanent magnet 10 to the south pole of permanent magnet 2 17. Similarly, the south pole of permanent magnet 3 and the north pole of permanent magnet 4 18 are in contact with the left and right inner surfaces of the right C-shaped support 2, respectively. The start and end points of the right magnetic circuit 16 are from the north pole of permanent magnet 3 to the south pole of permanent magnet 4 18. The magnetic fields generated by these two sets of permanent magnets are approximately uniform linear magnetic fields with the same direction, and are perpendicular to the input and output directions of the electrical signals, minimizing interference caused by skewed axes. Different magnetic field directions only affect the sign of the output signal. Therefore, even if the directions of the left magnetic circuit 15 and the right magnetic circuit 16 are opposite, it has no impact on the performance and results of the flow rate control structure. This structural design also follows the principle of minimum magnetic circuit, allowing the conductive fluid to obtain a uniform and wide-ranging magnetic field environment within a limited gap.

[0028] Between the two sets of permanent magnets, a rectangular cross-section racetrack-shaped conductive fluid channel 14 is formed, consisting of two bends and two straight segments. Compared with the ordinary open straight channel structure, it is completely sealed and less affected by interference. Moreover, the rectangular cross-section channel has less fluid flow resistance and is less affected by eddy currents compared with the ordinary circular cross-section.

[0029] The inner wall 5 of the racetrack-shaped conductive fluid channel is in contact with the second permanent magnet 17 and the third permanent magnet 3 respectively. The outer wall 4 of the racetrack-shaped conductive fluid channel is at a certain distance from the first permanent magnet 10 and the fourth permanent magnet 18. The distance between the inner and outer walls is used as the width of the racetrack-shaped conductive fluid channel.

[0030] The upper part of the racetrack-shaped conductive fluid channel is the upper wall 6, on which a first electrode 8 and a third electrode 9 are disposed; and the first and third electrodes are respectively disposed on two straight segments of the upper wall 6. The lower part of the racetrack-shaped conductive fluid channel is the lower wall 7, on which a second electrode 12 and a fourth electrode 13 are disposed; and the second and fourth electrodes are disposed on straight segments of the lower wall 7. The distance between the upper and lower walls is used as the height of the racetrack-shaped conductive fluid channel.

[0031] The outer wall 4, inner wall 5, upper wall 6, and lower wall 7 of the channel should all be made of insulating, non-magnetic materials, such as plexiglass or polyester resin. These parts are bonded together using AB adhesive to form a conductive fluid channel 14. The channel is filled with a highly conductive and magnetically permeable gallium indium tin (GaInT) fluid. An annular gap is provided at the contact point between the conductive fluid channel and the electrode to ensure sufficient contact between the conductive fluid and the electrode, and to effectively prevent the GaInT from overflowing due to thermal expansion.

[0032] The electrodes should be made of highly conductive metals, such as copper or silver, to improve signal input efficiency and reduce noise in the output signal. The first electrode 8 and the second electrode 12 input voltage / current signals to provide the initial signal for flow rate control. Together with the left magnetic circuit 15, they induce flow of the conductive liquid. The flowing conductive fluid generates a motional electromotive force in the right magnetic circuit 16, which outputs a potential signal via the third electrode 9 and the fourth electrode 13 to detect the result of the flow rate control.

[0033] In this embodiment, assuming that the magnetic fields of the left magnetic circuit 15 and the right magnetic circuit 16 are uniform and equal, the first electrode 8 and the second electrode 12 are at the same potential, and the third electrode 9 and the fourth electrode 13 are at the same potential, then the current and potential in the conductive fluid channel will also be uniformly distributed. The working principle of a rectangular cross-section racetrack-shaped conductive fluid flow rate control device is as follows:

[0034] The working principle of a rectangular cross-section racetrack-shaped conductive fluid flow rate control device is based on magnetohydrodynamics. A conductive fluid channel 14 is filled with gallium indium tin (GaInT) conductive fluid, and this racetrack-shaped conductive fluid channel conducts electricity only at the electrode connection points. The linear regions on both sides of the racetrack-shaped fluid are in a magnetic field of equal magnetic induction intensity, with a magnitude of B. First, simulation software is used to determine the correspondence between current / voltage magnitude and flow velocity. After the conductive fluid in the conductive fluid channel 14 is energized, it flows under the action of the left-side magnetic circuit 15, with a flow velocity of V. α The flow of the conductive fluid cuts the magnetic field lines in the right-hand magnetic circuit 16, generating a motional electromotive force of magnitude E, where E = V. α ×B.

[0035] In practical applications, when flow rate control is required, the device should be used according to the following steps:

[0036] Step a: Control the external current / voltage source to be turned on and connected to the first electrode 8 and the second electrode 12; The external current / voltage source inputs a fixed value of electrical signal through the first electrode 8 and the second electrode 12;

[0037] Step b: When the conductive fluid in the conductive fluid channel is energized, it flows under the influence of the magnetic field and cuts the magnetic field lines to produce a continuous flow.

[0038] Step c: The electrical signal generated by the flow of the conductive fluid is transmitted to the acquisition circuit via the third electrode 9 and the fourth electrode 13. The acquisition circuit then acquires the voltage signal and transmits it to the computer. The computer performs signal processing such as low-pass filtering on the electrical signal to obtain the actual flow velocity of the conductive fluid. Based on this, the voltage / current is adjusted to achieve stable control of the flow velocity of the conductive fluid.

Claims

1. A racetrack-shaped conductive fluid velocity control device with a rectangular cross-section, characterized in that, Two C-shaped brackets are symmetrically set on the crossbeam of the metal I-shaped bracket (1), and the two C-shaped brackets are fixed on the upper left and right sides of the metal I-shaped bracket (1); A set of permanent magnets is arranged on the inner walls of both sides of the two C-shaped supports, and numbered sequentially from left to right. Permanent magnets 1 and 2 form the left magnetic circuit (15), and permanent magnets 3 and 4 form the right magnetic circuit (16). The south pole of permanent magnet 1 (10) contacts the left inner surface of the left C-shaped support (11), and the north pole of permanent magnet 2 (17) contacts the right inner surface of the left C-shaped support (11). The left magnetic circuit (15)... The starting point is the north pole face of permanent magnet No. 1 (10), and the ending point of the left magnetic circuit (15) is the south pole face of permanent magnet No. 2 (17); the south pole face of permanent magnet No. 3 (3) is in contact with the left inner surface of the right C-shaped support (2), and the north pole face of permanent magnet No. 4 (18) is in contact with the right inner surface of the right C-shaped support (2). The starting point of the right magnetic circuit (16) is the north pole face of permanent magnet No. 3 (3), and the ending point of the right magnetic circuit (16) is the south pole face of permanent magnet No. 4 (18). The left magnetic circuit (15) and the right magnetic circuit (16) pass perpendicularly through the two straight segments of the racetrack-shaped conductive fluid channel, and the magnetic field distribution is uniform and symmetrical. The first electrode (8) and the second electrode (12) input voltage / current signals to provide initial signals for controlling the flow rate, and work together with the left magnetic circuit (15) to make the conductive liquid flow; the flowing conductive fluid generates motional electromotive force in the right magnetic circuit (16), and outputs potential signals through the third electrode (9) and the fourth electrode (13) to detect the result of the flow rate control. A racetrack-shaped conductive fluid channel (14) consisting of two bends and two straight segments is formed between the two sets of permanent magnets; the longitudinal section of the racetrack-shaped conductive fluid channel (14) is rectangular, and the racetrack-shaped conductive fluid channel (14) is filled with conductive liquid; The inner wall of the racetrack-shaped conductive fluid channel is in contact with permanent magnet No. 2 and permanent magnet No. 3 respectively, and the outer wall of the racetrack-shaped conductive fluid channel is spaced at a certain distance from permanent magnet No. 1 and permanent magnet No. 4 respectively. The distance between the inner and outer walls is used as the width of the racetrack-shaped conductive fluid channel. Above the racetrack-shaped conductive fluid channel is the upper wall (6) of the channel, on which a first electrode (8) and a third electrode (9) are provided; and the first and third electrodes are respectively provided on two straight segments of the upper wall (6) of the channel. Below the racetrack-shaped conductive fluid channel is the lower wall (7) of the channel, on which a second electrode (12) and a fourth electrode (13) are provided; and the second and fourth electrodes are provided on the straight section of the lower wall (7).

2. The rectangular cross-section racetrack-shaped conductive fluid velocity control device according to claim 1, characterized in that: The fluid flow directions in the left magnetic circuit (15), the right magnetic circuit (16), and the racetrack-shaped conductive fluid channel (14) are perpendicular to the input voltage / current direction, respectively.

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