Sound wave modulation device and method for conducting fluid movement based on electric field and magnetic field driving and application

Abstract

The invention discloses a conductive fluid motion sound wave modulation device and method based on electric field and magnetic field driving and application, and relates to the technical field of sound wave control. The device includes a conductive fluid driving portion for driving a conductive fluid; the magnetic field generating device is used for generating a required magnetic field; the direct-current voltage source is used for providing a required voltage field; the acoustic flow cavity is used for providing a moving channel for the conductive fluid and providing a designed waveguide for the acoustic wave; and the ultrasonic receiving and generating device is used for receiving and generating ultrasonic waves. The sound wave control device has the advantages of being simple in structure and convenient to manufacture, and the problem that current flowing acoustics is difficult to achieve is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic wave modulation, and particularly to an acoustic wave modulation device, method and application based on a moving conductive fluid. Background Art

[0002] As an earliest energy carrier utilized by humans, sound has played a great role in promoting the development of human society. The development of acoustics and the utilization degree of acoustic waves indirectly also measure the development of human society. However, the coupling between acoustic waves and complex media remains a difficult topic, and researchers are unable to predict the propagation law of acoustic waves in complex, especially moving media. If an acoustic wave propagation model in complex moving media can be established to accurately predict the transmission characteristics of acoustic waves, it will greatly promote the development of various fields such as marine acoustics and military information transmission. The present patent currently provides a multifunctional ultrasonic modulation device under a specific acoustic waveguide, and successfully realizes functions including acoustic frequency shift, acoustic gyrotron, acoustic isolation device, acoustic diode, etc.

[0003] Currently, acoustic control devices involve different acoustic waves. The piezoelectric effect can be effectively used to control surface waves in surface waves to achieve modulation of surface waves such as frequency, amplitude, and delay. However, the control of bulk ultrasonic waves remains a major problem. Currently, the control of ultrasonic waves is mainly achieved by means of using nonlinear materials, phononic crystals, etc.

[0004] The acoustic control device of nonlinear materials introduces a nonlinear acoustic wave propagation medium, so that in the propagation process, in addition to the transmission of the fundamental wave, second and third harmonics will also be generated additionally. If the generation efficiency of the second and third harmonics is controlled, the result of controlling acoustic waves can be achieved.

[0005] However, this means of controlling acoustic waves using harmonics is greatly limited. Acoustic waves need to be in a large amplitude situation to generate harmonics, and nonlinear materials cannot be used in a large range. The traditional means of controlling acoustic waves using moving media has attracted great attention. The Doppler effect can be easily used to achieve the frequency shift of acoustic waves. However, the Doppler effect requires the flow velocity of the moving medium to match the sound velocity. If only the Doppler effect is used to control acoustic waves, either a fluid medium with an extremely low sound velocity or a medium with an extremely fast flow rate needs to be used, and both of these are difficult to obtain in actual experiments and are even more difficult to apply on a large scale.

[0006] It can be seen that the complexity and low realizability of acoustic wave control technology. Summary of the Invention

[0007] In order to solve the problems existing in the above background art and solve the dilemma of the complexity and difficulty of application of current acoustic control technology, the present invention specifically adopts the following technical solutions:

[0008] An acoustic wave modulation device for driving the movement of a conductive fluid based on electric and magnetic fields, comprising a conductive fluid driving device, a magnetic field generating device, an electric field generating device, an acoustic flow cavity, and an ultrasonic receiving and generating device;

[0009] The acoustic flow cavity provides a channel for the movement of the conductive fluid and a waveguide designed for sound waves, including an electromagnetic driving region and a Tesla cavity. The inlet and outlet of the Tesla cavity are connected to the electromagnetic driving region, forming a whole loop; the cavity is filled with a conductive liquid;

[0010] The conductive fluid driving device drives the conductive fluid, specifically including an inert metal electrode and a graphite electrode, which are connected to the electric field generating device to provide a voltage field; the inert metal electrode and the graphite electrode are placed in parallel at both ends of the electromagnetic driving region, and the two electrodes are parallel to the flow direction;

[0011] The magnetic field generating device is used to provide a magnetic field and is arranged directly below the electromagnetic driving region;

[0012] The ultrasonic transmitting and receiving device is used to receive and generate ultrasonic waves, including a pair of ultrasonic transducers, which are respectively at both ends of the fluid inlet and outlet of the Tesla cavity.

[0013] Further, the Tesla cavity is an improved Tesla valve, and the improvement is specifically to optimize the angle of the two Tesla cascades to obtain a Tesla valve with the minimum fluid resistance.

[0014] Further, the electric field generating device is specifically a DC voltage source with a voltage of 0 - 12V.

[0015] Further, the magnetic field generating device includes but is not limited to a permanent magnet.

[0016] Further, the conductive liquid includes an aqueous solution of sodium sulfate or other physically and electrochemically stable conductive fluids.

[0017] The present invention also provides an acoustic wave modulation method for driving the movement of a conductive fluid based on electric and magnetic fields, which uses the above acoustic wave modulation device for modulation. Specifically, the movement rate of the conductive liquid is adjusted by adjusting the voltage magnitude, and then the acoustic wave transmission characteristics are adjusted.

[0018] The present invention also provides an application of an acoustic wave modulation device for driving the movement of a conductive fluid based on electric and magnetic fields in an acoustic wave amplitude tuner, an acoustic wave phase modulator, an acoustic wave frequency modulator, or an acoustic non-reciprocal modulator.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] 1. The acoustic wave modulation device based on the driving of electric and magnetic fields for the movement of conductive fluids provided by the present invention has a Tesla fluid acoustic cavity manufactured by a 3D printing machine, with low preparation cost, convenience and speed. Moreover, the principle of the driving method using the Lorentz force is simple, and high-flow velocity can be achieved inside the micro-fluid cavity.

[0021] 2. The novel micro-fluid pump adopted by the present invention drives the fluid by means of non-contact, noiseless and ultra-high fluid driving efficiency. There is no need for a mechanical fan to drive the fluid flow, and no additional mechanical noise is introduced. Moreover, the accurate manipulation of the flow velocity can be achieved by adjusting the conductive solution and the magnitude of the DC voltage.

[0022] 3. The cavity of the present invention has the characteristics of tunability and easy integration. The size of the device can be adjusted according to the usage conditions, and it can be conveniently coupled in other systems.

[0023] 4. The acoustic wave modulation method provided by the present invention has a simple structure and is easy to operate, and the manufacturing difficulty of the device is low; the cost of the preparation materials is low and easy to obtain.

[0024] 5. The acoustic wave modulation device based on the driving of electric and magnetic fields for the movement of conductive fluids provided by the present invention can modulate the acoustic waves transmitted in the cavity in real time and dynamically by integrating a new type of pump driven by electromagnetic force, which forms a sharp contrast with the traditional passive modulation methods.

[0025] 6. The present invention creatively adopts a flowing fluid medium combined with an asymmetric Tesla valve as a means of acoustic regulation, providing a new means for acoustic regulation, breaking the limitations of the existing acoustic regulation mainly relying on acoustic metamaterials, phononic crystals, and topological acoustics, and breaking through the dependence on materials and structures of the original methods. The device proposed in this research has hybrid characteristics, combining fluid flow, electromagnetic drive, and acoustic wave control, which represents an interdisciplinary research among these fields.

[0026] 7. The present invention connects the acoustic and fluid fields, builds a bridge between the acoustic and fluid fields, and the proposed active control method solves the problems of limited regulation means and unsatisfactory effects existing in the traditional acoustic wave regulation methods in the face of complex application scenarios. This method extends the concept of fluid diodes to the acoustic field, which means that it is possible to achieve unidirectional acoustic transmission that can be turned on, off, or modulated in real time. For example, in ultrasonic detection, unidirectional acoustic transmission can make the detection signal act more concentratedly on the target object, reduce the scattering and interference of the signal, and significantly improve the accuracy and precision of the detection. Description of the Drawings

[0027] Figure 1 It is an experimental diagram of the phase modulation of acoustic waves by the Tesla acoustic streaming cavity.

[0028] Figure 2It is the modulation time-domain diagram of three kinds of sound waves in the Tesla acoustic streaming cavity.

[0029] Figure 3 It is the simulation optimization process diagram of the improved Tesla cavity.

[0030] Figure 4 It is the schematic structural diagram of a sound wave modulation device provided in the embodiment of the present invention.

[0031] Figure 5 It is the schematic structural diagram of a voltage-field-driven acoustic flow cavity provided in the embodiment of the present invention. Detailed implementation manners

[0032] The technical problem to be solved by the present invention is to solve the problems of mechanical noise, low efficiency, poor integration effect, etc. of the traditional fluidic acoustic cavity by adopting a new method of fluidic acoustic cavity. The aim is to invent a new noiseless, integrable, non-contact multifunctional acoustic device.

[0033] Based on the Lorentz force driven by electromagnetic force, the present invention designs an active acoustic cavity for guiding current fluid with electromagnetic field driving fluid flow by cooperating with electric field and magnetic field. By controlling the field strength of the electric field region, the fluid flow is driven, and a tunable multifunctional acoustic device is realized in a wide frequency band, and acoustic modulation devices such as acoustic wave amplitude tuner, acoustic wave phase modulator, acoustic wave frequency modulator, acoustic non-reciprocal modulator, etc. are realized.

[0034] The sound wave modulation device based on the movement of the guiding current fluid driven by electric field and magnetic field provided by the present invention is as Figure 4 shown, and specifically includes: a guiding current fluid driving device for driving the guiding current fluid; a magnetic field generating device for generating the required magnetic field; a DC voltage source for providing the required voltage field; an acoustic flow cavity for providing a movement channel for the guiding current fluid and a waveguide designed for sound waves; an ultrasonic receiving and generating device for receiving and generating ultrasonic waves.

[0035] The acoustic flow cavity includes an electromagnetic driving region and an improved Tesla valve region. The entrances and exits of the improved Tesla valve region are communicated with the electromagnetic fluid driving region, and an overall loop is formed, as Figure 5 shown, Figure 5 The container containing the conductive liquid in is the electromagnetic driving region, which forms a passage with the Tesla valve region as a whole. Another form of expression of this acoustic flow cavity is as Figure 4 shown. The electromagnetic driving region and the improved Tesla valve region are located in the same container, and the acoustic flow cavity is obtained by 3D printing as a whole. The acoustic flow cavity is manufactured by 3D printing, with a simple structure and easy to manufacture. The manufacturing materials of the cavity include but are not limited to resins. The liquid filled in the cavity includes but is not limited to sodium sulfate aqueous solution, and other physically and electrochemically stable guiding current fluids can also be used.

[0036] Further, the Tesla valve optimizes the cascading angle of two Tesla stages through fluid simulation. By applying the same inlet velocity, the fluid flow velocity analysis is carried out inside the Tesla cavities with different cascading angles, and the optimization results are referred to Figure 3 . The Tesla valve with the minimum fluid resistance is selected as the model for the final experiment. The fluid flow direction in the circuit can be controlled by the magnetic field direction. The forward flow (the mode with almost unobstructed fluid) and the reverse flow (the mode with extremely obstructed fluid) in the Tesla valve are selected, and the flow direction in the circuit can be adjusted according to the fluid flow direction required by the acoustic wave regulation experiment.

[0037] The described electrically conductive fluid driving device includes an inert metal electrode and a graphite electrode, which are connected to an electric field generating device to provide a voltage field; the inert metal electrode and the graphite electrode are located at both ends of the electromagnetic driving region and are placed in parallel. The two electrodes are parallel to the flow direction and are located directly above the magnetic field generating device.

[0038] The magnetic field generating device is arranged directly below the electromagnetic driving region. The magnetic field generating device is used to provide a magnetic field. Under the action of the bias magnetic field, the fluid is still stationary at this time. When an electric field is applied to the electromagnetic driving region, the electrically conductive fluid starts to flow under the action of the Lorentz force. And the Lorentz force is stable and unchanged, which makes the flow tend to be more laminar. Under the action of the flow, the flow in the asymmetric Tesla cavity has a modulating effect on the acoustic wave. The magnetic field generating device includes but is not limited to a permanent magnet, such as a neodymium iron boron magnet, which has a low cost and is easy to obtain. Specifically, as Figure 4 shown, there is an embedded permanent magnet obtained by 3D printing below the electromagnetic driving region.

[0039] The electric field generating device includes but is not limited to a DC voltage generator, and the voltage regulation range of the voltage generator is 0 - 12V. As Figure 5 shown, the two ends of the DC voltage source are respectively connected to the inert metal electrode and the graphite electrode, and the overall provides a voltage field for the electromagnetic driving region

[0040] The ultrasonic transmitting and receiving device includes a pair of ultrasonic transducers respectively arranged at both ends of the fluid inlet and outlet of the described Tesla cavity.

[0041] Example 1:

[0042] This example provides an acoustic wave modulation device for the movement of an electrically conductive fluid driven by an electric field and a magnetic field, including a modified Tesla cavity, a liquid filled in the cavity, a magnetic field generating device, an electrically conductive flow driving device, a DC voltage source, and an ultrasonic transmitting and receiving device.

[0043] The conductive fluid driving device includes an inert metal electrode and a graphite electrode, which are connected to a DC voltage source to provide a voltage field, use Lorentz force or Ampere force to drive the conductive liquid, and adjust the movement rate of the conductive liquid by adjusting the voltage; the ultrasonic receiving and generating device includes a pair of ultrasonic transducers of the same model.

[0044] The acoustic flow cavity is filled with a conductive aqueous solution, and ultrasonic transducers are located at both ends of the cavity.

[0045] Turn on the magnetic field generating device and the ultrasonic transmitting and receiving device, and adjust the conductive fluid driving device to drive the sodium sulfate aqueous solution in the acoustic power cavity. First, change the current between the electrode plates by adjusting the voltage. The movement of charged ions in the magnetic field is driven by the Lorentz force to change the movement speed of the conductive solution. The voltage is proportional to the flow rate. By adjusting the voltage to 4-12v, the solution in the power cavity is driven to flow at different speeds to achieve the purpose of adjusting the sound wave transmission characteristics. At this time, near the 100kHz frequency band, the frequency amplitude increases with the increase of the applied DC voltage, the phase changes suddenly at 8v, and the phase is almost maintained in a certain range at 8-12v. Its phase change refers to Figure 1 It can be observed that the phase of the sound wave changes suddenly around 8V, and this phase change can be used to prepare a sound wave phase modulation device. For example, if the modulation generates a sound wave with a completely opposite phase, the sound wave of a specific frequency band can be eliminated through the destructive interference of the sound wave.

[0046] By adjusting the voltage to select different modes, the solution in the power chamber is driven to flow at different speeds to achieve the purpose of adjusting the transmission characteristics of the sound wave. At this time, the modulation effect of the sound wave is achieved in the three modes. For specific modulation effects, refer to Figure 2 . Figure 2 Among the three modes, mode 1 represents the propagation characteristics of sound waves at low flow rate and static state, and mode 2 represents the sound waves modulated by electromagnetic force inside the Tesla acoustic cavity. It can be found that its amplitude has changed. Figure 1 It can be known that such amplitude change is caused by the change of phase. Mode 3 shows another result of modulating the sound wave, whose amplitude is further reduced, and the sound wave on the time scale is concentrated at a later position, which shows that the sound wave contains a delay in the time domain after modulation. The three modes show that the modulation effect of the acoustic flow cavity of the present invention on the sound wave is significant.

[0047] Furthermore, the ultrasonic transmitting and receiving assembly includes a pair of ultrasonic transducers and a needle hydrophone or transducer. The needle hydrophone is used to test the sound pressure signal inside the improved Sierra cavity except for the inlet and outlet, and can be placed at any position inside the cavity according to the needs of the acoustic experiment.

[0048] It will be understood that the present invention is described by way of some embodiments, and those skilled in the art will know that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. Additionally, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. An acoustic wave modulation device for guiding the movement of a conductive fluid driven by an electric field and a magnetic field, characterized in that, It includes a conductive fluid driving device, a magnetic field generating device, an electric field generating device, an acoustic flow cavity, and an ultrasonic receiving and generating device; The acoustic flow cavity provides a movement channel for the conductive fluid and a designed waveguide for sound waves. It includes an electromagnetic driving region and a Tesla cavity. The inlet and outlet of the Tesla cavity are connected to the electromagnetic driving region to form a whole loop; the cavity is filled with a conductive liquid; The conductive fluid driving device drives the conductive fluid, specifically including an inert metal electrode and a graphite electrode, which are connected to the electric field generating device to provide a voltage field; the inert metal electrode and the graphite electrode are placed in parallel at both ends of the electromagnetic driving region, and the two electrodes are parallel to the flow direction; The magnetic field generating device is used to provide a magnetic field and is arranged directly below the electromagnetic driving region; The ultrasonic transmitting and receiving device is used to receive and generate ultrasonic waves, including a pair of ultrasonic transducers, which are respectively at both ends of the fluid inlet and outlet of the Tesla cavity.

2. The acoustic wave modulation device for guiding the movement of conductive fluid driven by electric field and magnetic field according to claim 1, wherein The Tesla cavity is an improved Tesla valve. The improvement is specifically to optimize the angle of cascading of two Teslas to obtain a Tesla valve with the minimum fluid resistance.

3. The acoustic wave modulation device for guiding the movement of conductive fluid driven by electric field and magnetic field according to claim 2, wherein The electric field generating device is specifically a DC voltage source with a voltage of 0 - 12V.

4. The acoustic wave modulation device for guiding the movement of conductive fluid driven by electric field and magnetic field according to claim 3, wherein The magnetic field generating device includes but is not limited to a permanent magnet.

5. The acoustic wave modulation device for guiding the movement of conductive fluid driven by electric field and magnetic field according to claim 4, characterized in that, The conductive liquid includes an aqueous solution of sodium sulfate or other physically and electrochemically stable conductive fluids.

6. A method for modulating sound waves by the movement of a conductive fluid driven by an electric field and a magnetic field, which uses the modulation device described in any one of claims 1-5 for modulation, characterized in that, By adjusting the voltage magnitude, the movement rate of the conductive liquid is adjusted, and thus the acoustic wave transmission characteristics are adjusted.

7. Application of a conductive fluid motion acoustic wave modulation device driven by an electric field and a magnetic field according to any one of claims 1 - 5 in an acoustic wave amplitude tuner, an acoustic wave phase modulator, an acoustic wave frequency modulator, or an acoustic non-reciprocal modulator.

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