CN115824381A - Line vibration sensor with magnetohydrodynamic pump - Google Patents
Line vibration sensor with magnetohydrodynamic pump Download PDFInfo
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- CN115824381A CN115824381A CN202211500059.8A CN202211500059A CN115824381A CN 115824381 A CN115824381 A CN 115824381A CN 202211500059 A CN202211500059 A CN 202211500059A CN 115824381 A CN115824381 A CN 115824381A
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Abstract
The invention discloses a linear vibration sensor with a magnetohydrodynamic pump, wherein a shell of the linear vibration sensor is composed of a metal top cover and a metal base, and a groove is arranged in the metal base; the groove and the interior of the metal top cover jointly form a cavity, a U-shaped magnet is arranged in the cavity, two electromotive force polar plates of a power pump are arranged on the inner side surface of the top of the U-shaped magnet, two permanent magnets are arranged on the inner side surfaces of two ends of an opening at the bottom, and a fluid channel is arranged in the U-shaped magnet; the straight line section at the bottom of the outer side of the fluid channel is an outer electrode, the straight line section at the bottom of the inner side of the fluid channel is an inner electrode, and the fluid channel is filled with conductive fluid. The invention can effectively improve the performance of the magnetohydrodynamic linear vibration sensor on detecting low-frequency signals, thereby realizing the expansion of the sensor frequency spectrum.
Description
Technical Field
The invention relates to the field of magnetohydrodynamics, in particular to a linear vibration sensor with a magnetohydrodynamics pump.
Background
The sensors commonly used for measuring the vibration of the spacecraft comprise a piezoresistive type linear vibration sensor and a piezoelectric type linear vibration sensor, wherein the piezoresistive type linear vibration sensor is commonly used for measuring low-frequency vibration, but the piezoresistive type linear vibration sensor has the problems of poor impact resistance and large influence of temperature; the piezoelectric type wire vibration sensor is often used for measuring high frequency vibration, but it has problems that the measurement accuracy is not high and a signal of zero frequency cannot be measured.
In view of the above-mentioned shortcomings and drawbacks of vibration measurement sensors, magnetohydrodynamic linear vibration sensors have come into force. The magnetohydrodynamics-based linear vibration sensor has no mechanical abrasion phenomenon among internal firmware, and has the advantages of high yield strength, good dynamic performance, wide damping adjustment range and the like. Although the bandwidth of the magnetohydrodynamic wire vibration sensor can reach 1KHz, the magnetohydrodynamic wire vibration sensor faces the problem of poor detection performance of low-frequency (< 1 Hz) signals. In order to solve the problem of poor low-frequency performance, a detection circuit of the linear vibration sensor is generally redesigned to improve the detection performance of weak signals and expand the working bandwidth of the linear vibration sensor.
The method of utilizing the compensation circuit is to process at a signal output end, is greatly influenced by the characteristics of the sensor, is not suitable for being applied in a rapid system environment, limits the application field of the magnetohydrodynamic linear vibration sensor, and does not fundamentally improve the low-frequency performance of the sensor.
Disclosure of Invention
The invention aims to provide a linear vibration sensor with a magnetohydrodynamic pump by improving the mechanical structure of the sensor aiming at the defects in the prior art, so that the sensor can measure vibration signals in a low-frequency range, the detection performance of the low-frequency signals can be effectively improved, and the aim of stable work in severe environments such as strong impact and the like can be fulfilled.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention relates to a line vibration sensor with a magnetohydrodynamic pump, which is characterized in that a shell of the line vibration sensor is jointly formed by a metal top cover and a metal base, and a groove is arranged in the metal base; recess and the inside cavity that forms jointly of metal top cap be provided with in the cavity: the device comprises a U-shaped magnet, two electromotive force polar plates of a power pump, two permanent magnets and a fluid channel;
the top of the U-shaped magnet is contacted with the inner surface of the top cover, and two ends of an opening at the bottom of the U-shaped magnet are tightly connected with the groove;
a left electromotive force polar plate and a right electromotive force polar plate are respectively arranged on two sides of the inner side surface of the top of the U-shaped magnet;
the inner side surfaces of two ends of the opening at the bottom of the U-shaped magnet are respectively provided with a left permanent magnet and a right permanent magnet;
a fluid channel is arranged in the U-shaped magnet, and the fluid channel is a closed loop consisting of a channel outer ring, a channel inner ring, a left channel side wall and a right channel side wall;
the top of the fluid channel is clamped between the left electromotive force polar plate and the right electromotive force polar plate;
the bottom of the fluid channel is clamped between the left permanent magnet and the right permanent magnet;
filling the fluid channel with a conductive fluid;
the top straight line segment of the channel outer ring is in contact with the U-shaped magnet;
setting a straight line section at the bottom of the channel outer ring as an outer electrode and contacting with the base groove;
and a straight line segment at the bottom of the channel inner ring is arranged as an inner electrode.
The linear vibration sensor with the magnetohydrodynamic pump is also characterized in that the thicknesses of the left channel side wall, the right channel side wall, the channel inner ring and the channel outer ring are equal.
By applying a voltage to the two emf plates, an additional velocity is generated to the conductive fluid held in the fluid channel between the two emf plates.
And the inner electrode and the outer electrode respectively output potential signals for measuring the potential difference between the channel outer ring and the channel inner ring.
The axis of the metal top cover, the metal base, the U-shaped magnet, the left permanent magnet, the right permanent magnet, the left electromotive force polar plate, the right electromotive force polar plate, the left channel side wall, the right channel side wall, the channel outer ring and the channel inner ring is perpendicular to the axis of the measurement direction of the magnetohydrodynamic wire vibration sensor.
The left permanent magnet and the right permanent magnet generate uniformly distributed magnetic fields on two sides of the conductive fluid in the fluid channel, and the residual magnetism direction is in the vertical direction of the measuring direction, so that a vertical magnetic field environment is formed.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention is based on the magnetohydrodynamics electromagnetic induction principle, uses the conductive fluid material with good fluidity and excellent conductivity, utilizes the principle that the fluidity of the fluid, the channel wall and the magnetic field area generate relative motion, cuts the magnetic induction line to generate the motional electromotive force to detect the line vibration information, is different from the traditional line vibration sensor, and has the characteristics of high reliability, high strength and long service life because no solid moving part exists and no mechanical abrasion exists in the fluid motion measurement.
2. The invention improves the structure of the line vibration sensor, adds the magnetohydrodynamic pump on the structure of the magnetohydrodynamic line vibration sensor, the magnetohydrodynamic pump applies voltage to the conductive fluid in the fluid channel, the electric field generated by the voltage is required to be mutually vertical to the magnetic field, under the action of the mutually vertical electric field and the magnetic field, the conductive fluid in the fluid channel flows at an additional flow velocity, the measurement of line vibration is realized at low frequency, and the low-frequency detection performance of the line vibration sensor is improved.
3. Compared with other non-mechanical fluid driving technologies, the magnetohydrodynamic pump driving technology has the advantages that the structure is simple, the processing is easy, the speed of the fluid pump driving the conductive fluid can be controlled by adjusting the voltage of the power supply of the fluid pump, the polarity of the voltage of the power supply can be changed, the movement direction of the conductive fluid can be controlled, the magnetohydrodynamic pump can drive the fluid in two directions, the using power consumption is low, and the like.
4. The magnetohydrodynamic pump can adopt two power supply modes; the direct current source magnetohydrodynamic pump drives the conductive fluid by only connecting conductive electrodes on the front side and the rear side of the channel, and after voltage is applied to the fluid channel through the electrodes, the conductive fluid generates electromagnetic force under the action of a magnetic field so as to drive the fluid to flow; the alternating current source magnetohydrodynamic pump has a more complex structure than the direct current source magnetohydrodynamic pump, and the alternating current source magnetohydrodynamic pump consists of a winding coil and a magnet, but has the advantages of long service life of the motor, few bubbles and the like.
Drawings
FIG. 1 is a front cross-sectional view of a wire vibration sensor with a magnetohydrodynamic pump of the present invention;
FIG. 2 is a left side cross-sectional view of the wire vibration sensor with the magnetohydrodynamic pump of the present invention;
reference numbers in the figures: 1. a metal top cover; a U-shaped magnet; 3. a right electromotive force plate; 4. a right channel side wall; 5. an electrically conductive fluid; 6. a right permanent magnet; 7. a groove; 8. a metal base; 9. an outer electrode; 10. a left permanent magnet; 11. an inner electrode; 12. an inner ring of the channel; 13. a left electromotive force polar plate; 14. a left channel side wall; 15. a channel outer ring; 16. an axis of symmetry.
Detailed Description
In the embodiment, a magnetic circuit design in the casing of the line vibration sensor with the magnetohydrodynamic pump is shown in fig. 1 and 2, the casing of the line vibration sensor is formed by a metal top cover 1 and a metal base 8 together, and a groove 7 is arranged in the metal base 8; recess 7 forms a cavity with metal top cap 1 is inside jointly, is provided with in the cavity: the device comprises a U-shaped magnet 2, two electromotive force polar plates of a power pump, two permanent magnets and a fluid channel; the structure of the sensor mainly guides the configuration of the conductive fluid and the magnetic field, so that the finally obtained sensor has a compact structure, good fluid tightness and a closed uniform magnetic field. Therefore, the metal top cover 1 and the metal base 8 of the shell should be made of soft magnetic materials with high saturation magnetic flux density, such as iron-nickel alloy, so that the influence of the internal magnetic circuit of the sensor on surrounding devices is prevented, and the influence of external electromagnetic interference on the internal sensing part of the shell is avoided.
The top of the U-shaped magnet 2 is contacted with the inner surface of the top cover 1, and two ends of the bottom opening of the U-shaped magnet 2 are tightly connected with the groove 7; the U-shaped magnet 2 should also be made of soft magnetic material with high saturation magnetic flux density, so as to inhibit the influence of external electromagnetic field, ensure the sensitivity of the sensor, and form a closed magnetic circuit with a pair of permanent magnets. The strength and distribution uniformity of the closed magnetic circuit are important to the design of the sensor. The magnetic leakage phenomenon is reduced, and the linearity of induced electromotive force generated when the conductive fluid cuts a magnetic field and the stability of the driving fluid of the magnetohydrodynamic pump are guaranteed to be important.
A left electromotive force polar plate 13 and a right electromotive force polar plate 3 are respectively arranged on two sides of the inner side surface of the top of the U-shaped magnet 2; the head of the electromotive force polar plate of the power pump is sealed by sealant at the position contacted with fluid, and the tail of the electromotive force polar plate is led out of a lead to the top of the sensor through an electrode hole and is used for being connected with an external power supply. By applying a voltage to the two emf plates, an additional velocity is generated to the conductive fluid 5 held in the fluid channel between the two emf plates. The material of the left electromotive force plate 13 and the right electromotive force plate 3 should be a good conductor, such as a metal copper material. The electromotive force polar plate of the power pump has higher conductivity and smaller resistance, so that the accuracy of the electromotive force of the power pump can be improved.
The inner side surfaces of two ends of the bottom opening of the U-shaped magnet 2 are respectively provided with a left permanent magnet 10 and a right permanent magnet 6; the magnetic pole at one side of the permanent magnet is connected with the inner wall of the U-shaped magnet, the magnetic pole at the other side of the permanent magnet is contacted with the outer wall of the corresponding side wall of the fluid channel, and the bottom of the permanent magnet is embedded into the groove 7, so that the magnetic field leakage situation and the working air gap can be reduced, the permanent magnet can exert the maximum magnetic energy, the uniform magnetic field distribution and the magnetic field intensity are kept, and the sensitivity of the sensor is improved. The left permanent magnet 10 and the right permanent magnet 6 are made of permanent magnetic materials capable of providing a strong magnetic field, the directions of the magnetic poles of the two permanent magnets need to be consistent, the north pole face of the left permanent magnet 10 can be selected to be tightly attached to the inner wall of the U-shaped magnet 2, the south pole face of the right permanent magnet 6 is placed in a mode of being tightly attached to the inner wall of the U-shaped magnet 2, the south pole face of the left permanent magnet 10 can be further selected to be tightly attached to the inner wall of the U-shaped magnet 2, accordingly, the right permanent magnet 6 is placed in a mode of being tightly attached to the inner wall of the U-shaped magnet 2 through the north pole face, and the performance of the sensor cannot be affected by different placing modes. The left permanent magnet 10 and the right permanent magnet 6 generate uniformly distributed magnetic fields on two sides of the conductive fluid 5 in the fluid channel, and the remanence direction is in the vertical direction of the measuring direction, so that a vertical magnetic field environment is formed.
A fluid channel is arranged in the U-shaped magnet 2, and the fluid channel is a closed loop consisting of a channel outer ring 15, a channel inner ring 12, a left channel side wall 14 and a right channel side wall 4; in specific implementation, the left channel side wall 14, the right channel side wall 4, the channel inner ring 12 and the channel outer ring 15 are equal in thickness and are adhered by the sealant, so that the conductive fluid 5 can be effectively prevented from overflowing. The top of the fluid channel is clamped between the left electromotive force polar plate 13 and the right electromotive force polar plate 3; the bottom of the fluid channel is clamped between the left permanent magnet 10 and the right permanent magnet 6; the fluid channel is filled with conductive fluid 5; the bottoms of the two side walls of the fluid channel are embedded into the groove 7, the top of the fluid channel is in contact with the inner wall of the U-shaped magnet 2, the right channel side wall 4 and the left channel side wall 14 are in a runner shape, and the structure is smaller in flow resistance when fluid flows compared with a rectangular structure and more convenient to process compared with a circular structure. The right channel side wall 4 and the left channel side wall 14 are made of insulating non-magnetic-conducting materials, and can be made of polycarbonate or organic glass, so that the distribution of the potential on the electrodes is prevented from being influenced.
The top straight line segment of the channel outer ring 15 is in contact with the U-shaped magnet 2; the straight line section at the bottom of the channel outer ring 15 is an outer electrode 9 and is in contact with the base groove 7; the straight line segment at the bottom of the channel inner ring 12 is provided as an inner electrode 11. Except that the channel section at the bottom of the channel outer ring 15 and the channel inner ring 12 are good conductors, the rest parts of the channel outer ring and the channel inner ring are all made of insulating non-magnetic conducting materials, so that potential distribution is not influenced, and mutual coupling influence between two electromagnetic signals can be effectively reduced.
The inner electrode 11 and the outer electrode 9 respectively output potential signals for measuring the potential difference between the channel outer ring 15 and the channel inner ring 12. In a specific implementation, the materials of the inner electrode 11 and the outer electrode 9 should also be selected to be good conductors.
The axes of the metal top cover 1, the metal base 8, the U-shaped magnet 2, the left permanent magnet 10, the right permanent magnet 6, the left electromotive force polar plate 13, the right electromotive force polar plate 3, the left channel side wall 14, the right channel side wall 4, the channel outer ring 15 and the channel inner ring 12 are vertical to the axis of the measurement direction of the magnetohydrodynamic line vibration sensor.
In this embodiment, assuming that the magnetic field is uniform, and the inner and outer electrodes are respectively equal in potential, the current and potential in the fluid chamber will be uniformly distributed, and the working principle of the linear vibration sensor with the magnetohydrodynamic pump is as follows:
the working principle of the magnetohydrodynamic linear vibration sensor utilizes the conductive characteristic of a magnetofluid material, and the basic idea is the principle of electromagnetic induction. As shown in fig. 1, the left permanent magnet 10 and the right permanent magnet 6 form a magnetic field environment perpendicular to the measurement direction and uniform. The conductive fluid 5 is filled in the fluid channel which is conductive only at the upper and lower walls of the bottom straight channel section, the rest being insulated. The straight line segment at the bottom end of the fluid channel is positioned in the magnetic field environment formed by the left permanent magnet 10 and the right permanent magnet 6. The whole sensor and a rotating object to be measured are fixed together, when a line vibration signal alpha is input from the outside in the sensitive axis direction of the magnetohydrodynamic line vibration sensor, a relative speed v is generated between the magnetofluid and the permanent magnet because the magnetofluid has low viscosity and is almost fixed relative to a fixed inertial coordinate system, and the magnetofluid cuts magnetic lines of force, so that a dynamic electromotive force E is generated between inner and outer wall electrodes, namely E = vXB.
When the detected vibration is low frequency (< 1 Hz), the conductive fluid is difficult to keep relatively static with the inertial space and moves with the sensor housing; the additional flow velocity is introduced into the fluid ring through the magnetohydrodynamic pump, the relative velocity is increased, and the improvement of the magnetohydrodynamic linear vibration sensor on the low-frequency detection performance is realized.
Claims (6)
1. A line vibration sensor with a magnetohydrodynamic pump is characterized in that a shell of the line vibration sensor is formed by a metal top cover (1) and a metal base (8), and a groove (7) is formed in the metal base (8); recess (7) and metal top cap (1) inside form a cavity jointly be provided with in the cavity: the device comprises a U-shaped magnet (2), two electromotive force polar plates of a power pump, two permanent magnets and a fluid channel;
the top of the U-shaped magnet (2) is contacted with the inner surface of the top cover (1), and two ends of the bottom opening of the U-shaped magnet (2) are tightly connected with the groove (7);
a left electromotive force polar plate (13) and a right electromotive force polar plate (3) are respectively arranged on two sides of the inner side surface of the top of the U-shaped magnet (2);
the inner side surfaces of two ends of the bottom opening of the U-shaped magnet (2) are respectively provided with a left permanent magnet (10) and a right permanent magnet (6);
a fluid channel is arranged in the U-shaped magnet (2), and the fluid channel is a closed loop consisting of a channel outer ring (15), a channel inner ring (12), a left channel side wall (14) and a right channel side wall (4);
the top of the fluid channel is clamped between the left electromotive force polar plate (13) and the right electromotive force polar plate (3);
the bottom of the fluid channel is clamped between the left permanent magnet (10) and the right permanent magnet (6);
filling the fluid channel with an electrically conductive fluid (5);
the top straight line segment of the channel outer ring (15) is in contact with the U-shaped magnet (2);
setting a straight line section at the bottom of the channel outer ring (15) as an outer electrode (9) and contacting with the base groove (7);
and a straight line section at the bottom of the channel inner ring (12) is set as an inner electrode (11).
2. A line vibration sensor with a magnetohydrodynamic pump, according to claim 1, characterized in that the left channel side wall (14), the right channel side wall (4), the channel inner ring (12), the channel outer ring (15) are of equal thickness.
3. A line vibration sensor with a magnetohydrodynamic pump according to claim 1, characterised in that the additional velocity is generated to the conductive fluid (5) held in the fluid channel between the two emf plates by applying a voltage to the two emf plates.
4. A line vibration sensor with a mhd pump according to claim 1 where the inner and outer electrodes (11, 9) output potential signals for measuring the potential difference between the outer (15) and inner (12) channel rings.
5. A line vibration sensor with a magnetohydrodynamic pump, in accordance with claim 1, characterized in that: the axis of the metal top cover (1), the metal base (8), the U-shaped magnet (2), the left permanent magnet (10), the right permanent magnet (6), the left electromotive force polar plate (13), the right electromotive force polar plate (3), the left channel side wall (14), the right channel side wall (4), the channel outer ring (15) and the channel inner ring (12) is perpendicular to the axis of the measurement direction of the magnetohydrodynamic line vibration sensor.
6. A linear vibration sensor with a mhd pump according to claim 1 where the left (10) and right (6) permanent magnets generate a uniformly distributed magnetic field on both sides of the conductive fluid (5) in the fluid channel with the remanence direction in the perpendicular direction to the measurement direction, thus forming a perpendicular magnetic field environment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211500059.8A CN115824381A (en) | 2022-11-28 | 2022-11-28 | Line vibration sensor with magnetohydrodynamic pump |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211500059.8A CN115824381A (en) | 2022-11-28 | 2022-11-28 | Line vibration sensor with magnetohydrodynamic pump |
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| Publication Number | Publication Date |
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| CN115824381A true CN115824381A (en) | 2023-03-21 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211500059.8A Pending CN115824381A (en) | 2022-11-28 | 2022-11-28 | Line vibration sensor with magnetohydrodynamic pump |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115979409A (en) * | 2023-03-22 | 2023-04-18 | 天津大学 | Angular vibration sensor based on magnetohydrodynamics and angular vibration detection method |
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2022
- 2022-11-28 CN CN202211500059.8A patent/CN115824381A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115979409A (en) * | 2023-03-22 | 2023-04-18 | 天津大学 | Angular vibration sensor based on magnetohydrodynamics and angular vibration detection method |
| CN115979409B (en) * | 2023-03-22 | 2023-06-09 | 天津大学 | Angular vibration sensor based on magnetohydrodynamics and angular vibration detection method |
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