A finite element simulation method for plasma noise reduction based on equivalent sound source model

Abstract

The application discloses a kind of finite element simulation methods based on equivalent sound source model plasma noise reduction, belong to plasma noise reduction simulation field.It includes the following steps: S1, determine plasma model parameter;S2, establish pressure acoustics control equation;Based on control equation respectively solve the sound pressure component under the action of plasma corresponding sound source term, heat source term alone, obtain total sound pressure by linear superposition;S3, construct plasma sound source equivalent model;S4, the sound source term, heat source term obtained by plasma sound source equivalent model are input pressure acoustics control equation, and the noise reduction process under the action of plasma noise reduction equipment is obtained by solving using finite element method.The application provides a kind of efficient plasma noise reduction simulation method, by establishing plasma equivalent sound source model, the complex plasma physical process is simplified as equivalent source term in acoustic equation, avoids directly solving expensive multi-field coupling problem, makes calculation efficiency improve several orders of magnitude.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of plasma noise reduction simulation, more particularly, to a finite element simulation method for plasma noise reduction based on an equivalent sound source model. BACKGROUND

[0002] With the acceleration of technological progress, more and more noise-generating machines and equipment have entered daily life, and the rising level of noise has had a significant negative impact on people's physical and mental health. To address this challenge, various strict noise regulation laws have been introduced, thereby placing higher demands on noise reduction technologies. In particular, in the fields of aviation, road traffic, and industrial ventilation systems, noise control has become particularly complex and challenging.

[0003] Currently, the main noise control technologies are mainly divided into two categories: passive and active. Passive noise control technology relies on the sound energy dissipation characteristics of porous materials, resonators, etc., and it is effective in high-frequency noise control, but it often requires a large amount of material and a large structure when dealing with low-frequency noise, which becomes impractical in space-limited application scenarios.

[0004] Active noise control technology, such as active noise cancellation, cancels noise at a specific location by generating an "anti-noise" signal that is opposite in phase to the original noise. This method has been proven effective in dealing with low-frequency tone noise in simple geometric spaces such as headphones and pipes. However, in three-dimensional space, this method requires a large number of sensors and transducers, and the computational cost is high. In addition, this technology introduces additional sound energy into the sound field, which may cause the sound pressure level at certain locations to rise instead of falling.

[0005] Plasma acoustics is an emerging interdisciplinary field that mainly studies the interaction mechanism between plasma and sound waves, as well as the generation, control, and absorption of sound waves using plasma characteristics. Unlike traditional acoustic transducers, plasma acoustic devices do not require physical diaphragms or mechanical vibration components, but instead produce sound waves by directly modulating the ionization state of gas molecules.

[0006] The sound radiation of a traditional loudspeaker originates from the vibration of the diaphragm, and its impedance characteristics are mainly determined by the mechanical system; while the sound radiation of a plasma sound source directly comes from the periodic change of air volume, and its impedance characteristics are closer to the characteristic impedance of air itself, which gives it an inherent advantage in impedance matching. In addition, the plasma sound source has no moving parts, is simple in structure, can work in extreme environments (such as high temperature, high humidity, and strong corrosion), and theoretically has no aging and fatigue problems, with a lifespan mainly dependent on the reliability of the power supply system.

[0007] As the core numerical simulation technology in the industry, the Finite Element Method (FEM) has experienced significant theoretical innovation and application expansion in recent decades. Among them, the Discontinuous Galerkin FEM (DG-FEM) as a new generation of high-performance simulation technology has gradually attracted attention.

[0008] Based on the finite element method, the coupling simulation of plasma behavior and acoustic propagation can be realized to analyze the noise reduction process and effect of the plasma device, providing a theoretical basis for structure optimization and performance improvement. However, plasma simulation itself involves the coupling of multiple physical fields such as electricity, chemistry, and fluid, and the numerical model is complex. Especially for plasma noise reduction simulation of three-dimensional structure, the computational complexity is high. To overcome this problem, we propose a finite element simulation method for plasma noise reduction based on an equivalent sound source model. SUMMARY

[0009] The purpose of the present application is to provide a finite element simulation method for plasma noise reduction based on an equivalent sound source model to solve the problems raised in the background art.

[0010] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0011] A finite element simulation method for plasma noise reduction based on an equivalent sound source model, comprising the following steps:

[0012] S1, determine the plasma model parameters, including at least propagation medium parameters, plasma device geometric parameters, and plasma electrical parameters;

[0013] S2, establish a pressure acoustic control equation, with sound pressure, sound source term, and heat source term as core variables; based on the control equation, solve the sound pressure components under the action of the plasma corresponding sound source term and heat source term respectively, and obtain the total sound pressure by linear superposition;

[0014] S3, construct an equivalent model of plasma sound source, including:

[0015] S3.1, correlate the sound pressure component with the alternating control voltage of the plasma, and determine the spatial parameters of the discharge region combined with the geometric parameters of the plasma device;

[0016] S3.2, based on the voltage-current characteristics of corona discharge, establish the correlation between the excitation voltage and current of the plasma, and further obtain the corresponding relationship between the current and the plasma sound source term and heat source term;

[0017] S3.3, construct a transfer function, convert the sound pressure collected by the monitoring point into an alternating control voltage for adjusting the plasma through the transfer function, realize the matching of the impedance of the monitoring point and the impedance of the plasma terminal;

[0018] S4, input the sound source term and the heat source term obtained by the plasma sound source equivalent model into the pressure acoustic control equation, and solve the noise reduction process under the action of the plasma noise reduction equipment by the finite element method.

[0019] Preferably, the specific expression of the pressure acoustic control equation in step S2 is:

[0020] ;

[0021] Wherein, p is the density of the propagation medium, p is the sound pressure, f ω is the sound source term, h ω is the heat source term, w is the angular frequency, c is the sound speed, is the wave number.

[0022] Preferably, the specific expression of the sound pressure component in step 2 is:

[0023] The sound pressure component corresponding to the dipole sound source term:

[0024] ;

[0025] The sound pressure component corresponding to the heat source term:

[0026] ;

[0027] Total sound pressure p t Satisfies the total sound pressure p t (r) = p f ( r ) +p h ( r );Wherein∣ r ∣is the distance from the field point to the sound source, v 0 is the volume of the discharge area, θ is the angle between the sound wave propagation and the observation direction, γ is the specific heat capacity of the gas.

[0028] Preferably, step S3.1 includes constructing the relationship between the sound source and the alternating control voltage:

[0029] Known p f ( r ) and p h ( rexpressions, respectively, for the integral terms and the control voltage U AC correlation is performed to control the generation of the plasma sound source: ;

[0030] The area of the plasma discharge region is known S and the electrode spacing d， The volume of the plasma discharge region is then v 0= Sd, resulting in:

[0031] ;

[0032] wherein F ω is the total sound source term in the form of a volume force, H ω is the total heat source term in the form of a thermal power, f is the sound source term per volume, h is the heat source term per volume, U AC is the alternating control voltage of the plasma.

[0033] Preferably, the voltage-current characteristic of the corona discharge in step S3.2 is established on the basis of the Townsend formula, in particular: the direct current I DC in dependence on the direct bias voltage U DC satisfies wherein C is a constant, U 0 is the starting voltage.

[0034] Preferably, the excitation voltage in step S3.2 is the superposition of the direct bias voltage and the alternating control voltage: ; which is inserted into the Townsend formula and the second-order small terms are neglected, resulting in the alternating current component: .

[0035] Preferably, the current and the corresponding sound source term and heat source term in step S3.2 are as follows:

[0036] Current and sound source term: on the basis of the ion mobility μ i and the electrode spacing d of the discharge region, the total sound source term in the form of a volume force:

[0037] ;

[0038] Current and heat source term: on the basis of the Joule heat principle, the total heat source term in the form of a thermal power:

[0039] .

[0040] Preferably, the transfer function in step S3.3 is constructed based on the one-dimensional plane wave transmission line principle, and the specific expression is:

[0041] ;

[0042] In the formula, ; ;

[0043] ; ; ;

[0044] Wherein, θ 1、 θ 2 is the coefficient term associated with the plasma parameters, f is the correlation coefficient of the current and the sound source term, h is the correlation coefficient of the current and the heat source term, r is the reflection coefficient of the plasma terminal impedance and the characteristic impedance of the medium, pt ( x 0) is the total sound pressure collected at the monitoring point P1, Z L is the plasma terminal impedance, ρc is the characteristic impedance of the propagation medium (obtained by the product of the medium density ρ and the sound speed c ), k is the wave number (satisfying k = ω / c , ω is the angular frequency), L r Length of the plasma discharge area, C p T : The product of the specific heat capacity at constant pressure of the propagation medium C p and the temperature T , C p is the specific heat capacity at constant pressure of the propagation medium, T is the temperature of the propagation medium, e j2kL is the phase factor of the sound wave propagating back and forth in the plasma discharge area;

[0045] The control voltage U AC , .

[0046] Preferably, the propagation medium parameters in step S1 include medium density, sound speed, the plasma device geometric parameters include area, spacing, length of the discharge region, and the plasma electrical parameters include DC bias voltage, amplitude and frequency of AC control voltage, and starting voltage.

[0047] Compared with the prior art, the present application has the beneficial effects that:

[0048] (1) Overcoming the problem of high computational complexity of traditional simulation methods: the present application provides an efficient plasma noise reduction simulation method, which simplifies the complex plasma physical process into an equivalent source term in the acoustic equation by establishing a plasma equivalent sound source model, avoiding the direct solution of expensive multi-field coupling problems, and making the computational efficiency improve by several orders of magnitude.

[0049] (2) Maintaining engineering accuracy while greatly simplifying the calculation process: compared with the existing full coupling simulation method, the present application converts the complex plasma acoustic problem into a pure acoustic simulation problem under the premise of maintaining sufficient engineering accuracy. This simplification not only makes the simulation feasible, but also enables traditional acoustic simulation software to be directly applied to plasma noise reduction research, greatly reducing the technical threshold.

[0050] (3) The equivalent sound source model of the present application enables researchers to quickly predict and optimize the plasma noise reduction effect of large-scale equipment on ordinary computing platforms. This provides a practical simulation tool for the actual engineering design of plasma noise reduction devices, significantly shortening the research and development cycle. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a schematic diagram of a plasma device in a 3D impedance tube model;

[0052] Figure 2 is a simulation sound pressure cloud map of a 3D impedance tube plasma noise reduction device based on the finite element method;

[0053] Figure 3 is a graph of the variation of sound absorption coefficient with frequency;

[0054] Figure 4 is an application schematic diagram of a plasma noise reduction device of a range hood;

[0055] Figure 5 is a sound pressure level cloud map of a certain cross section of a range hood;

[0056] Figure 6 is a frequency spectrum graph of the outlet monitoring point with different amounts of plasma. DETAILED DESCRIPTION

[0057] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments.

[0058] Embodiments

[0059] A finite element simulation method based on equivalent sound source model plasma noise reduction, comprising the following steps:

[0060] Step S1, determine the plasma model parameters, parameters at least include propagation medium parameters (as shown in Table 1), plasma device geometry parameters (as shown in Table 2) and plasma electrical parameters (as shown in Table 3); wherein the propagation medium parameters include medium density, sound velocity, plasma device geometry parameters include the area of discharge region, spacing, length, plasma electrical parameters include DC bias voltage, AC control voltage amplitude and frequency, starting voltage.

[0061] Table 1 propagation medium parameters

[0062]

[0063] Table 2 plasma device geometry parameters

[0064]

[0065] Table 3 plasma electrical parameters

[0066]

[0067] Step S2, establish pressure acoustic control equation, control equation with sound pressure, sound source term, heat source term as the core variable; based on the control equation, the sound pressure component under the action of the plasma corresponding sound source term, heat source term is solved respectively, the total sound pressure is obtained by linear superposition;

[0068] Specifically, the specific expression of the pressure acoustic control equation is:

[0069] ;

[0070] Wherein, ρ is the propagation medium density, p is the sound pressure, f ω is the sound source term, h ω is the heat source term, ω is the angular frequency, c is the sound velocity, is the wave number.

[0071] The specific expression of the sound pressure component is:

[0072] The sound pressure component corresponding to the dipole sound source term:

[0073] ;

[0074] The sound pressure component corresponding to the heat source term:

[0075] ;

[0076] Total sound pressure p t Satisfy the total sound pressure p t (r) = p f ( r ) +p h ( r ); wherein | r | is the distance from the field point to the sound source, r | is the distance from the field point to the sound source, v 0 is the volume of the discharge region, θ is the angle between the sound wave propagation and the observation direction, γ is the specific heat capacity of the gas.

[0077] Step S3, constructing an equivalent model of the plasma sound source, comprising:

[0078] S3.1, associate the sound pressure component with the alternating control voltage of the plasma, and determine the spatial parameters of the discharge region in combination with the geometric parameters of the plasma device;

[0079] Specifically, step S3.1 includes constructing the relationship between the sound source and the alternating control voltage:

[0080] Given p f ( r ) and p h ( r ) expression, respectively, the integral term and the control voltage U AC are associated, thereby controlling the generation of the plasma sound source: ;

[0081] Given the area of the plasma discharge region S and the electrode spacing d， , then the volume of the plasma discharge region v 0= Sd, Get:

[0082] ;

[0083] wherein, F ω is the total sound source term in the form of volume force, H ω is the total heat source term in the form of heat power, f is the sound source term per unit volume, h is the heat source term per unit volume,U AC AC control voltage for plasma.

[0084] S3.2, based on the voltage-current characteristic of corona discharge, the relationship between the excitation voltage and current of the plasma is established, and then the corresponding relationship between the current and the plasma sound source term and the heat source term is obtained;

[0085] Specifically, the voltage-current characteristic of corona discharge is established based on the Townsend formula, specifically: the direct current I DC The relationship with the direct current bias voltage U DC satisfies , wherein C is a constant, U 0 is the starting voltage.

[0086] Wherein, the excitation voltage is the superposition of the direct current bias voltage and the alternating current control voltage: ; Substitute it into the Townsend formula and ignore the second order small term to get the alternating current component:

[0087] .

[0088] Specifically, in the corona discharge, the positive ions drift in the electric field, collide with neutral air molecules to transfer momentum, and form the total force. The relationship between the total force and the current is determined by the "ion mobility μi" and "electrode spacing d". Among them, the corresponding relationship between the current and the sound source term and the heat source term is:

[0089] Current and sound source term: based on the ion mobility μi i and the electrode spacing d of the discharge region, the total sound source term in the form of body force:

[0090] ;

[0091] Current and heat source term: based on the Joule heat principle, the total heat source term in the form of heat power:

[0092] .

[0093] Specifically, the heat power of the corona discharge comes from the "Joule heat of ion motion", and the total heat power H(t) is approximately equal to "voltage x current";

[0094] ; ; ; Substitute and expand and ignore the second order small term to get the alternating component of the total heat power: ; Substitute the alternating current I AC and IDC Simplify to get: .

[0095] S3.3, construct the transfer function, through the transfer function to convert the sound pressure collected by the monitoring point into the AC control voltage for adjusting the plasma, so as to realize the matching of the impedance of the monitoring point and the impedance of the plasma terminal.

[0096] Wherein, the transfer function θ is the core bridge to realize the "target impedance matching", and the sound pressure of the measurement point P1 is converted into the control voltage of the plasma terminal P2. pt(-x 0 ) . U AC .

[0097] The impedance of the plasma terminal Z L In order to make the impedance of the monitoring point Z AC Match the terminal impedance Z L According to the principle of one-dimensional plane wave transmission line, we get: ;

[0098] According to the one-dimensional pressure and velocity wave equation, we get: ;

[0099] ; ;

[0100] ; ; ;

[0101] Substitute the above formula into the following formula to get the balance relationship between sound pressure and particle velocity:

[0102] ;

[0103] Transfer function: The transfer function is constructed based on the principle of one-dimensional plane wave transmission line, and the specific expression is:

[0104] ;

[0105] In the formula, ; ;

[0106] ; ; ;

[0107] Wherein, θ 1, θ 2 is the coefficient term related to the plasma parameters, f is the correlation coefficient of current and sound source term,h The correlation coefficient between the current and the heat source term is given. r The reflection coefficient is the sum of the plasma terminal impedance and the dielectric characteristic impedance. pt ( x 0) represents the total sound pressure level collected at monitoring point P1. Z L The plasma terminal impedance, ρc The characteristic impedance of the propagation medium (derived from the medium density) ρ With the speed of sound c (The product is obtained) k wave number (satisfying) k = ω / c , ω (angular frequency) L r The length of the plasma discharge region, C p T Specific heat capacity at constant pressure of the propagation medium C p With temperature T The product of C p The specific heat capacity at constant pressure of the propagation medium, T The temperature of the propagation medium, e j2kL This is the phase factor for the round-trip propagation of sound waves within the plasma discharge region;

[0108] The control voltage can be obtained through the transfer function. U AC , .

[0109] Step S4: Input the sound source term and heat source term obtained from the plasma sound source equivalent model into the pressure acoustic control equation, and solve it using the finite element method to obtain the noise reduction process under the action of the plasma noise reduction device.

[0110] In this application, based on the sound pressure at the monitoring point p t The control voltage is obtained through the transfer function. U AC Thus, the corresponding force source f and heat source are obtained. h By inputting this into the governing equations and performing finite element analysis, the noise reduction process under the action of the plasma noise reduction device can be obtained.

[0111] The numerical simulation of the prior art for plasma noise reduction needs to completely solve the multi-physical field coupling problem of electricity, chemistry, fluid mechanics and acoustics, and the demand for computing resources is extremely large, especially for three-dimensional large structures, which is almost infeasible. The present application simplifies the complex plasma physical process into an equivalent source term in the acoustic equation by establishing a plasma equivalent sound source model, avoids directly solving the expensive multi-field coupling problem, and improves the calculation efficiency by several orders of magnitude.

[0112] Example 1: Simulation of 3D impedance tube model plasma noise reduction device, see Figures 1-3 ;

[0113] As Figure 1 is a schematic diagram of a plasma device in a 3D impedance tube model. The plasma ionizes the air locally through a high-voltage electric field to generate an ion current, forming an impedance matching the sound field, thereby absorbing sound.

[0114] Figure 2 is a simulation sound pressure contour (300Hz) of a 3D impedance tube plasma noise reduction device based on the finite element method. As can be seen from the figure, due to the action of the plasma, the sound wave will be absorbed in the plasma device, thereby achieving noise reduction.

[0115] Figure 3 is a graph of the average sound absorption coefficient of the monitoring point P1 plane varying with frequency. As can be seen from the figure, within 2000Hz, the sound absorption coefficient can reach 0.86~1.

[0116] Example 2: Simulation of plasma noise reduction device in range hood application, see Figures 4-6 .

[0117] As Figure 4 is a schematic diagram of the application of a plasma noise reduction device in a certain type of range hood. The turbine in the range hood is the source of noise generated by the range hood. The plasma noise reduction device is arranged around the turbine of the range hood, thereby achieving noise reduction of the range hood equipment.

[0118] Figure 5 is a sound pressure level contour of a certain cross section of the range hood. At the plasma equipment, the sound pressure level is high, indicating that the sound is absorbed by the plasma device, and as the number of plasma installations increases, the sound pressure level at the outlet is significantly reduced.

[0119] Figure 6 is a frequency spectrum graph of the outlet monitoring point with different numbers of plasma. Table 4 is a comparison of the noise reduction amount at the outlet with different numbers of plasma. The plasma noise reduction device is installed on the left side, front side and rear side of the turbine, respectively. From Figure 6 and Table 4, it can be seen that: the main noise reduction frequency band of the plasma is about 10~500Hz, and the noise reduction amount increases with the number of blocks.

[0120] Table 4: Comparison of noise reduction at the outlet for different plasma quantities

[0121]

[0122] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A finite element simulation method for plasma noise reduction based on an equivalent sound source model, characterized in that, Includes the following steps: S1. Determine the plasma model parameters, which include at least the propagation medium parameters, plasma device geometric parameters, and plasma electrical parameters; S2. Establish pressure acoustic control equations, with sound pressure, sound source term, and heat source term as core variables; based on the control equations, solve for the sound pressure components under the individual action of the sound source term and heat source term corresponding to the plasma, and obtain the total sound pressure through linear superposition. The specific expression for the sound pressure component is as follows: The sound pressure component corresponding to the dipole sound source term: ； The sound pressure component corresponding to the heat source term: ； Total sound pressure p t Satisfying total sound pressure p t (r) = p f ( r ) +p h ( r ); among which | r | represents the distance from the field point to the sound source. v 0 represents the volume of the discharge region. θ The angle between the direction of sound wave propagation and the direction of observation. γ This refers to the specific heat ratio of the gas. f ω For the sound source term, h ω Here, ω is the heat source term, ω is the angular frequency, and c is the speed of sound. Wave number; S3. Construct an equivalent model of the plasma sound source, including: S3.

1. Correlate the sound pressure component with the AC control voltage of the plasma, and determine the spatial parameters of the discharge region by combining the geometric parameters of the plasma device; Specifically, this includes establishing the relationship between the sound source and the AC control voltage: Known p f ( r ) and p h ( r The expression combines the integral term with the control voltage. U AC By establishing a correlation, the generation of the plasma sound source can be controlled: ; The area of ​​the plasma discharge region is known. S and electrode spacing d， The volume of the plasma discharge region v 0= Sd, get: ； in, F ω The total sound source term is in the form of volume force. H ω Let f be the total heat source term in the form of thermal power, and let f be the sound source term per unit volume. h For the heat source term per unit volume, U AC The AC control voltage for the plasma; S3.2 Based on the voltage-current characteristics of corona discharge, establish the correlation between the excitation voltage and current of plasma, and then obtain the correspondence between current and plasma acoustic source term and heat source term; S3.3 Construct a transfer function to convert the sound pressure collected at the monitoring point into an AC control voltage for regulating the plasma, thereby achieving impedance matching between the monitoring point and the plasma terminal impedance; S4. Input the sound source term and heat source term obtained from the plasma sound source equivalent model into the pressure acoustic control equation, and solve the noise reduction process under the action of the plasma noise reduction device by the finite element method.

2. The finite element simulation method for plasma noise reduction based on an equivalent sound source model according to claim 1, characterized in that: The specific expression of the pressure acoustic control equation in step S2 is as follows: ； Where ρ is the density of the propagation medium and p is the sound pressure.

3. The finite element simulation method for plasma noise reduction based on an equivalent sound source model according to claim 1, characterized in that: The voltage-current characteristic of the corona discharge described in step S3.2 is established based on the Townsend formula, specifically: DC current I DC With DC bias voltage U DC Relationship satisfaction ,in C It is a constant. U 0 represents the starting voltage.

4. The finite element simulation method for plasma noise reduction based on an equivalent sound source model according to claim 3, characterized in that: The excitation voltage mentioned in step S3.2 is the superposition of DC bias voltage and AC control voltage: ; Substituting this into the Townsend formula and ignoring the second-order minor terms, we obtain the alternating current components: .

5. The finite element simulation method for plasma noise reduction based on an equivalent sound source model according to claim 4, characterized in that: The correspondence between the current and the sound source term and heat source term mentioned in step S3.2 is as follows: Current and Sound Source Terms: Based on Ion Mobility μ i The total sound source term in the form of volume force, including the electrode spacing d in the discharge region: ； Current and heat source terms: Based on the Joule heating principle, the total heat source term in the form of thermal power: 。 6. The finite element simulation method for plasma noise reduction based on an equivalent sound source model according to claim 5, characterized in that: The transfer function described in step S3.3 is constructed based on the principle of a one-dimensional plane wave transmission line, and its specific expression is as follows: ； In the formula, ; ; ； ； ； in, θ 1. θ 2 represents the coefficients associated with plasma parameters. f The correlation coefficient between current and sound source term. h The correlation coefficient between the current and the heat source term is given. r The reflection coefficient is the sum of the plasma terminal impedance and the dielectric characteristic impedance. pt ( x 0) represents the total sound pressure level collected at monitoring point P1. Z L The plasma terminal impedance, ρc The characteristic impedance of the propagation medium, k For wave number, L r The length of the plasma discharge region, C p T Specific heat capacity at constant pressure of the propagation medium C p With temperature T The product of C p The specific heat capacity at constant pressure of the propagation medium, T The temperature of the transmission medium, e j2kL This is the phase factor for the round-trip propagation of sound waves within the plasma discharge region; The control voltage can be obtained through the transfer function. U AC , .

7. The finite element simulation method for plasma noise reduction based on an equivalent sound source model according to claim 1, characterized in that: The propagation medium parameters mentioned in step S1 include medium density and sound velocity; the plasma device geometric parameters include the area, spacing, and length of the discharge region; and the plasma electrical parameters include DC bias voltage, AC control voltage amplitude and frequency, and starting voltage.

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