An adjustable frequency acoustic wave generating device based on thermoacoustic effect

Abstract

The application discloses a tunable acoustic wave generating device based on thermoacoustic effect and relates to the technical field of thermoacoustic generators. The device comprises a high-temperature tube, a thermoacoustic core and a frequency modulation tube. One end of the high-temperature tube is a closed end, and the other end is an open end. The open end of the high-temperature tube is connected with one end of the thermoacoustic core, the other end of the thermoacoustic core is connected with one end of the frequency modulation tube, and one or more than two openings exist on the wall of the other end of the frequency modulation tube. The application can adjust the effective acoustic length of the system by changing the opening state of the wall of the frequency modulation tube, so that the frequency of the acoustic wave can be flexibly regulated and controlled.

Description

Technical Field

[0001] This invention relates to the field of thermoacoustic generator technology, and more specifically to a tunable frequency sound wave generating device based on the thermoacoustic effect. Background Technology

[0002] Acoustic wave generation technology has wide applications in underwater communication, detection, firefighting, agriculture, and other fields. Traditional acoustic wave generating devices mainly rely on piezoelectric ceramic transducers or electrodynamic loudspeakers. These devices typically require multiple energy conversion stages, involving two energy conversions: heat to electricity to sound. Traditional systems are complex in structure, containing many vulnerable components such as coils, magnets, and moving parts, resulting in low overall conversion efficiency. Furthermore, for autonomous platforms requiring long-term deployment, power maintenance and recharging are difficult and costly.

[0003] The thermoacoustic effect works by establishing a temperature gradient in the regenerator to directly excite the working fluid to produce periodic oscillations, thus efficiently and directly converting thermal energy into sound energy. The core device has no moving parts, a simple and reliable structure, and can adapt to a wide range of pressure and temperature environments. It can utilize various heat sources such as industrial waste heat, solar thermal collection, and combustion.

[0004] However, existing thermoacoustic engines are designed and optimized to operate under a single, fixed condition in order to achieve maximum energy conversion efficiency under that specific condition. The frequency of their output sound waves is essentially determined by the geometry of the resonant cavity, and once manufactured, it is difficult to adjust flexibly over a wide range.

[0005] With the rapid development of acoustic application technologies, the requirements for sound source performance are increasing. Cutting-edge applications such as simulation of complex acoustic environments, multi-site acoustic detection, and communication urgently require sound wave transmitting devices capable of multi-frequency synthesis and rapid frequency switching. Existing single-frequency, fixed-output thermoacoustic generators clearly cannot meet these dynamic and complex control requirements. In agriculture, sound waves of specific frequencies can be used to repel pests and promote crop growth, and the tunable characteristics allow a single device to adapt to the sound wave requirements of different crops and different growth stages. In fire protection, sound waves of specific frequencies can be used for signal transmission in fire early warning systems, overcoming emergency communication barriers in dense smoke environments, and even exploring new fire extinguishing methods such as sound wave fire suppression.

[0006] The above application scenarios all place higher demands on the frequency flexibility, environmental adaptability, and reliability of acoustic wave equipment. Summary of the Invention

[0007] In view of this, the present invention provides a frequency-adjustable acoustic wave generator based on the thermoacoustic effect, which can solve the technical problem that the output frequency of the thermoacoustic generator is fixed and difficult to adjust flexibly over a wide range.

[0008] A frequency-tunable sound wave generator based on thermoacoustic effect includes a high-temperature tube, a thermoacoustic core, and a frequency-tuning tube; one end of the high-temperature tube is a closed end, and the other end is an open end; the open end of the high-temperature tube is connected to one end of the thermoacoustic core, the other end of the thermoacoustic core is connected to one end of the frequency-tuning tube, and there is one or more openings on the tube wall of the other end of the frequency-tuning tube.

[0009] Furthermore, the thermoacoustic core includes a heat exchanger, a regenerator, a cold heat exchanger, and a resonant tube, which are connected in sequence.

[0010] Furthermore, the number of thermoacoustic cores is one, two, three, four, five, or six. The first-stage thermoacoustic core is connected to the open end of the high-temperature tube. The heat exchanger of the second-stage thermoacoustic core is connected to the resonant tube of the first-stage thermoacoustic core. The cold heat exchangers of the subsequent-stage thermoacoustic cores are all connected to the resonant tubes of the preceding-stage thermoacoustic cores. The frequency tuning tube is connected to the resonant tube of the last-stage thermoacoustic core.

[0011] Furthermore, the frequency modulation tube has one or more openings on its wall with closable covers to form a frequency modulation unit; the frequency modulation unit actively controls the sound wave frequency by controlling the opening and closing of the covers at the openings.

[0012] Furthermore, the wall opening is sealed using a plug or tape.

[0013] Furthermore, the fittings of the frequency modulation tube are straight tubes, bent tubes, straight tubes with bypass, or U-shaped tubes with bypass.

[0014] Furthermore, the high-temperature tube is made of copper, iron, aluminum, stainless steel, plastic, or glass.

[0015] Furthermore, the thermoacoustic core is made of copper, iron, aluminum, stainless steel, plastic, or glass.

[0016] Furthermore, the frequency modulation tube is made of copper, iron, aluminum, stainless steel, plastic, or glass.

[0017] Furthermore, the connection between the high-temperature tube, the thermoacoustic core, and the frequency modulation tube is achieved using welding, bonding, flanges, ferrules, threads, sockets, or fusion welding.

[0018] Furthermore, the adjustable frequency sound wave generator controls the sound wave intensity by adjusting the heat power input to the heat exchanger.

[0019] Beneficial effects:

[0020] This invention achieves direct conversion of thermal energy into acoustic energy through a sequential connection structure of a high-temperature tube, a thermoacoustic core, and a frequency-modulated tube. The high-temperature tube, with one end closed and the other open, provides a stable high-temperature heat source input to the thermoacoustic core. After the thermoacoustic core converts thermal energy into acoustic energy, the sound wave is transmitted to the frequency-modulated tube. The other end of the frequency-modulated tube has one or more openings; by changing the opening state, the effective acoustic length of the system can be adjusted, thereby affecting the resonant frequency of the sound wave. This design allows for flexible adjustment of the sound wave frequency by adjusting the opening state without changing the overall structure, avoiding the complex operation of traditional thermoacoustic generators that require replacing the resonant cavity to change the frequency. Through this structural design, the system can achieve active frequency control while maintaining the advantages of thermoacoustic technology, such as no moving parts, simple structure, and high reliability, meeting the diverse frequency requirements of different application scenarios. This solution effectively solves the problem of existing thermoacoustic generators having fixed frequencies and being unable to adapt to multi-frequency application requirements, providing more flexible technical support for the application of acoustic wave generation technology in underwater communication, detection, fire fighting, agriculture, and other fields. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a sound wave transmitting device that utilizes wall openings for frequency modulation according to the present invention;

[0022] Figure 2 This is a schematic diagram of a sound wave transmitting device that utilizes wall openings and U-shaped tube frequency modulation according to the present invention.

[0023] Wherein: 1-High temperature tube, 2-Thermoacoustic core, 3-Frequency tuning tube, 4-Pipe opening, 21-Heat exchanger, 22-Regenerator, 23-Cold exchanger, 24-Resonant tube, 31-Pipe fitting, 32-First wall opening, 33-Second wall opening, 34-Third wall opening, 35-U-shaped tube. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] Example 1:

[0026] The structure of this embodiment is as follows: Figure 1 As shown, it includes a connected high-temperature tube 1, a thermoacoustic core 2, and a frequency modulation tube 3. The frequency modulation tube 3 includes a tube 31 and a first wall opening 32, a second wall opening 33, and a third wall opening 34 on the wall surface near the tube opening 4.

[0027] In this embodiment, the heat exchanger 21 and the cold heat exchanger 23 cause a temperature gradient in the regenerator 22. The acoustic power is initially generated in the regenerator 22 and then transmitted to the frequency modulation tube 3. By controlling the opening and closing state of the wall opening in the frequency modulation tube 3 in any other way, the effective resonant length of this system is changed, thereby realizing the active control of the sound wave frequency.

[0028] Example 2:

[0029] The structure of this embodiment is as follows: Figure 2 As shown, it includes a connected high-temperature tube 1, a thermoacoustic core 2, and a frequency modulation tube 3. The frequency modulation tube 3 includes a fitting 31, a first wall opening 32 on the wall near the wall opening 4, and a U-shaped tube 35.

[0030] In this embodiment, due to the action of the heat exchanger 21 and the cold heat exchanger 23, a temperature gradient is generated in the regenerator 22. The acoustic power is initially generated in the regenerator 22 and then transmitted to the resonant tube 24. Part of the acoustic power flows directly to the tube opening 4 in the tube 31, and part of the acoustic power flows through the U-shaped tube 35 and then re-enters the tube 1 and flows to the tube opening 4. By using any other method to control the opening and closing state of the wall opening 32 in the frequency modulation unit 3, the U-shaped tube 35 and the wall opening 32 work together to change the effective resonant length in the generator, thereby realizing the active control of the sound wave frequency.

[0031] Compared to traditional methods of obtaining sound waves using electrically driven piezoelectric materials, this acoustic wave emitting device obtains sound waves through a thermal sound-generating unit. Because it utilizes thermal energy to generate sound waves, it is applicable to more situations and can be driven by low-grade energy or solar energy, making it easier to obtain thermal energy, such as through solar thermal collection outdoors. It requires no mechanical moving parts, has a simple structure, high reliability, and long service life. Furthermore, the system's sound emission frequency can be flexibly adjusted by modifying the structural dimensions, boundary conditions, or working gas of the resonant system through a frequency modulation unit. The sound wave intensity can be flexibly adjusted by modifying the power of the input heat source and boundary conditions. It can stably and continuously convert thermal energy into high-power sound waves, operating stably and continuously with high power.

[0032] It should be noted that those skilled in the art should understand that the function of the thermoacoustic core 2 is to convert thermal energy into acoustic energy to generate sound waves; the function of the frequency modulation tube 3 is to transmit and modulate the sound field. It should also be noted that multiple thermoacoustic cores 2 and multiple frequency modulation tubes 3 can exist in the above system. In practical applications, they can be arranged according to specific needs, and no further specific limitations are made here.

[0033] In some more specific implementations, it should be noted that the pipe fitting 31 is preferably a straight pipe, but it can also be a curved pipe with a certain curvature.

[0034] In some specific implementations, the aforementioned fitting 31 can be a pipe of equal diameter, a pipe of reducing diameter, or a combination of a pipe of equal diameter and a pipe of reducing diameter. The material of fitting 1 can be 304 stainless steel. Of course, it is understood that in addition to 304 stainless steel, flexible hoses or other materials known to those skilled in the art that can be used in resonant systems can also be selected, without further specific limitations.

[0035] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A frequency-tunable sound wave generator based on thermoacoustic effect, characterized in that, It includes a high-temperature tube, a thermoacoustic core, and a frequency modulation tube; one end of the high-temperature tube is a closed end, and the other end is an open end; the open end of the high-temperature tube is connected to one end of the thermoacoustic core, the other end of the thermoacoustic core is connected to one end of the frequency modulation tube, and there is one or more openings on the tube wall of the other end of the frequency modulation tube.

2. The tunable frequency acoustic wave generator based on thermoacoustic effect as described in claim 1, characterized in that, The thermoacoustic core includes a heat exchanger, a regenerator, a cold heat exchanger, and a resonant tube, which are connected in sequence.

3. The tunable frequency acoustic wave generator based on thermoacoustic effect as described in claim 2, characterized in that, The number of thermoacoustic cores is one to six. The first-stage thermoacoustic core is connected to the open end of the high-temperature tube. The heat exchanger of the second-stage thermoacoustic core is connected to the resonant tube of the first-stage thermoacoustic core. The cold heat exchanger of each subsequent stage thermoacoustic core is connected to the resonant tube of the preceding stage thermoacoustic core. The frequency tuning tube is connected to the resonant tube of the last stage thermoacoustic core.

4. The tunable frequency acoustic wave generator based on thermoacoustic effect as described in claim 3, characterized in that, The frequency modulation tube has one or more openings on its wall with closable covers to form a frequency modulation unit; the frequency modulation unit actively controls the sound wave frequency by controlling the opening and closing of the covers at the openings.

5. The tunable frequency acoustic wave generator based on thermoacoustic effect as described in claim 4, characterized in that, The wall opening is sealed with a plug or tape.

6. The tunable frequency acoustic wave generator based on thermoacoustic effect as described in claim 5, characterized in that, The fittings for the frequency modulation tube are straight tubes, bent tubes, straight tubes with bypass, or U-shaped tubes with bypass.

7. The tunable frequency acoustic wave generator based on thermoacoustic effect as described in claim 6, characterized in that, The high-temperature tube, thermoacoustic core, and frequency modulation tube are made of copper, iron, aluminum, stainless steel, plastic, or glass.

8. The tunable frequency acoustic wave generator based on thermoacoustic effect as described in claim 7, characterized in that, The connections between the high-temperature tube, the thermoacoustic core, and the frequency modulation tube are made by welding, bonding, flanges, ferrules, threads, sockets, or fusion welding.

9. The tunable frequency based on thermoacoustic effect as described in claim 8 The sound wave generating device is characterized in that, The adjustable frequency sound wave generator controls the sound wave intensity by adjusting the heat power input to the heat exchanger.

Images