CN-120881493-B - Frequency-adjustable multifunctional pipeline acoustic end load, implementation method and application device

CN120881493BCN 120881493 BCN120881493 BCN 120881493BCN-120881493-B

Abstract

The application discloses a frequency-adjustable multifunctional pipeline acoustic end load, an implementation method and an application device, and relates to the field of muffler acoustic performance experiment measurement; the electroacoustic coupling structure array comprises at least one electroacoustic coupling structure, a shunt circuit module is connected between the positive electrode and the negative electrode of a coil of each electroacoustic coupling structure, the shunt circuit module comprises an operational amplifier, a positive electrode unit, a negative electrode unit, a first resistor and a second resistor, and the negative electrode unit comprises an adjustable impedance component. The application can effectively change the low-frequency impedance, further can accurately measure the low-frequency performance of the muffler, controls noise at low frequency, and only adjusts the circuit element to absorb noise at different frequencies under the condition that the mechanical structure is not changed. In addition, the acoustic experimental measurement of the muffler by a double-sound-source method can be realized.

Inventors

ZHAO XIAOCHEN
HUANG KAI
ZHANG XINYU
LIU CHEN
YANG JIE
GUO JIE
CAO YIPENG

Assignees

哈尔滨工程大学

Dates

Publication Date: 20260508
Application Date: 20250728

Claims (7)

1. The adjustable multifunctional pipeline acoustic end load is connected to the end of a sound elimination experimental device and is characterized by comprising an electroacoustic coupling structure array and at least one shunt circuit module, wherein the electroacoustic coupling structure array comprises at least one electroacoustic coupling structure; The shunt circuit module comprises an operational amplifier, a positive electrode unit, a negative electrode unit, a first resistor and a second resistor, wherein one end of the negative electrode unit is connected with the negative input end of the operational amplifier in series, the other end of the negative electrode unit is connected with the positive electrode of a coil of a corresponding electroacoustic coupling structure in series, one end of the positive electrode unit is connected with the positive input end of the operational amplifier in series, the other end of the positive electrode unit is grounded with the negative electrode of the coil of the corresponding electroacoustic coupling structure, one end of the first resistor is connected with the negative input end of the operational amplifier in series, the other end of the first resistor is connected with the output end of the operational amplifier in series, and one end of the second resistor is connected with the positive input end of the operational amplifier in series; the negative electrode unit comprises a negative electrode inductor, a negative electrode resistor and an adjustable impedance component which are sequentially connected in series, wherein the other end of the negative electrode inductor is connected with the positive electrode of a coil of a corresponding electroacoustic coupling structure in series; The positive electrode unit comprises a positive electrode inductor and a positive electrode resistor which are sequentially connected in series, wherein the other end of the positive electrode inductor is grounded; The acoustic impedance of the electroacoustic coupling structure is expressed as follows: ; Wherein, the Representing the acoustic impedance of the electroacoustic coupling structure, Is the vibrating diaphragm area of the electroacoustic coupling structure, Is the damping of the electroacoustic coupling structure, In units of imaginary numbers, Is the equivalent mass of the electroacoustic coupling structure, Is a frequency of a circle, and the frequency of the circle, Is the equivalent stiffness of the electroacoustic coupling structure, Is a force factor of the electroacoustic coupling structure, And The total resistance and the total inductance of the shunt circuit module respectively, Is the capacitance value of the adjustable impedance component.
2. The tunable multi-function conduit acoustic end load of claim 1, wherein when the tunable impedance component is a tunable capacitive plate, the capacitance of the tunable capacitive plate is tuned by a target frequency to tune a switch on the toggle plate to tune the capacitance of the tunable capacitive plate.
3. The tunable multi-function pipeline acoustic end load of claim 1, wherein the total resistance of the shunt circuit module is calculated from the negative resistance and the positive resistance and the total inductance of the shunt circuit module is calculated from the negative inductance and the positive inductance.
4. The tunable multi-functional conduit acoustic end load of claim 1, wherein the electroacoustic coupling structure is a moving iron, electromagnetic or moving coil speaker.
5. A method of implementing a tunable multi-function pipeline acoustic end load based on any one of claims 1-4, the method comprising: The capacitance value and the inductance value of the adjustable impedance component are determined according to the target frequency; the adjustable multifunctional pipeline acoustic end load according to any one of claims 1-4 is connected to the end of a sound elimination experiment device, a first impedance end experiment measurement is carried out, after the first impedance end experiment measurement, a second impedance end experiment measurement is carried out after the capacitance value and the inductance value of the adjustable impedance component are adjusted, and low-frequency acoustic performance data are obtained according to sound pressure data of different impedance measured through the two impedance end experiments.
6. A dual source measurement application device, wherein the infrasound source in the dual source measurement application device is the tunable multifunctional pipeline acoustic end load of any one of claims 1-4.
7. The apparatus of claim 6, further comprising a horn disposed between the secondary sound source and the air conduit for adjusting matching impedance of the diaphragm of the electroacoustic coupling structure and the fluid medium.

Description

Frequency-adjustable multifunctional pipeline acoustic end load, implementation method and application device Technical Field The application relates to the field of acoustic performance experimental measurement of silencers, in particular to a frequency-adjustable multifunctional pipeline acoustic end load, an implementation method and an application device. Background The pipeline muffler is used as one of effective pipeline noise control means, and has the characteristics of wide noise control frequency, convenience in maintenance and replacement and the like. In order to ensure that the muffler can completely realize the noise control of the target frequency, acoustic performance measurement is necessary for the muffler, and common acoustic measurement methods of the muffler include a double sound source method, a double load method and the like. The double-load method realizes measurement of acoustic performance of the muffler by changing different acoustic terminal impedances in experiments, and has simplicity superior to other methods. Existing sound-damping tips typically house sound-absorbing materials such as porous materials and sound-absorbing wedge structures. The porous material has remarkable sound absorption effect on middle and high frequency bands. The interior of the sound absorber has a plurality of tiny gaps and continuous bubbles, so that a good sound absorption channel is formed. When the sound waves are incident on the surface of the material, a portion of the sound waves penetrate into the material and propagate through the gaps and pores to produce viscous and frictional effects that gradually transform the sound energy into heat energy to be consumed. However, such as metallic sound absorbing materials and certain specially treated organic fiber materials, once damaged or aged, maintenance is difficult and even requires replacement of the entire material or parts of the assembly, increasing maintenance difficulties and costs. The section of the sound absorption wedge structure is gradually increased from small to match with the characteristic impedance of the fluid, so that the effect that the incident sound wave is absorbed almost completely without reflection is achieved. The design ensures that the sound absorption wedge has high sound absorption coefficient in medium and high frequency bands, and the normal incidence sound absorption coefficient can reach more than 0.99. However, the wedge structure occupies a large space and is difficult to maintain. However, the two conventional silencing ends have the defects of difficult maintenance and insignificant low-frequency sound absorption effect, so that the low-frequency acoustic performance data measured by the silencer is unreliable when the sound absorption ends are subjected to acoustic measurement. (the low frequency sound absorption coefficient of the ordinary sound absorption material is close to 0, the low frequency impedance is almost unchanged before and after the replacement of the sound absorption end, and the double-load method needs to rely on the change of the impedance to measure, the acoustic performance data of the muffler for low frequency measurement by the conventional sound absorption material is unreliable.) furthermore, the sound absorption material of the sound absorption end needs to be replaced when the double-load method is used for measurement, the installation state of each experiment is inconsistent, the repeatability of the experiment is poor, and therefore, the low frequency performance of the muffler needs to be tested by adopting a new acoustic end. Disclosure of Invention The application aims to provide a frequency-adjustable multifunctional pipeline acoustic end load, an implementation method and an application device, which can effectively change low-frequency impedance and further accurately measure the low-frequency performance of a muffler. Noise is controlled at low frequencies, and only the circuit elements are adjusted to absorb noise at different frequencies without changing the mechanical structure. In order to achieve the above object, the present application provides the following solutions: The application provides a multifunctional pipeline acoustic end load capable of adjusting frequency, which is connected to the end of a sound elimination experimental device and comprises an electroacoustic coupling structure array and at least one shunt circuit module, wherein the electroacoustic coupling structure array comprises at least one electroacoustic coupling structure; The shunt circuit module comprises an operational amplifier, a positive electrode unit, a negative electrode unit, a first resistor and a second resistor, wherein one end of the negative electrode unit is connected with a negative input end of the operational amplifier in series, the other end of the negative electrode unit is connected with a coil positive electrode of a corresponding electroacoustic coupling structur