Compressor shell noise prediction method and system based on acoustic boundary element model

Abstract

The invention discloses a compressor shell noise prediction method and system based on an acoustic boundary element model, and belongs to the technical field of noise prediction.The method specifically comprises the steps that a three-dimensional geometric model of a compressor shell is established, and an acoustic boundary element model of the compressor shell is established based on the three-dimensional geometric model of the compressor shell; discretizing the geometric model into boundary element units, identifying main noise sources inside and outside the compressor, loading the identified noise sources as boundary conditions into an acoustic boundary element model, setting acoustic boundary conditions and solving the acoustic boundary element model according to the actual working environment and material characteristics of the compressor shell, and obtaining the compressor shell. The acoustic response of the surface of the compressor shell is calculated, and the noise of the compressor shell is predicted based on the acoustic response, obtained through calculation, of the surface of the compressor shell; according to the method, the complex geometrical shape and material characteristics of the compressor shell are considered, and the noise source is positioned and quantified more accurately.

Description

Technical Field

[0001] The present invention belongs to the technical field of noise prediction, and in particular to a method and system for predicting compressor casing noise based on an acoustic boundary element model. Background Art

[0002] Compressors are widely used in various industrial and civil fields such as refrigeration, air conditioning, and gas compression. As the core equipment for energy conversion, they will generate mechanical vibration and aerodynamic noise during operation. These noises mainly come from gas pulsation inside the compressor, unbalanced forces of rotating parts, and vibration of the outer shell. Especially under high load and high speed, the noise problem is particularly serious, which not only affects the working environment of operators, but also may cause noise pollution to the surrounding environment, affecting the reliability and service life of the equipment.

[0003] In terms of compressor noise prediction, the existing technology mainly relies on the use of noise testers for noise testing. As far as noise testing technology is concerned, it has played an important role in the research of compressor noise prediction, but there are still certain shortcomings. This technology is limited by defects such as high cost, long time consumption, difficulty in testing large units, and large background noise. It can only be used for physical models that have been produced, which is not convenient for application in the production optimization design stage of manufacturers.

[0004] For example, the Chinese patent with the authorization announcement number CN113761679B discloses a method and device for predicting compressor noise, wherein the method includes: determining relevant information of a multi-stage compressor unit, wherein the multi-stage compressor unit includes multiple single-stage compressor units; inputting the relevant information of the multiple single-stage compressor units into the prediction model to obtain the predicted sound pressure values ​​of the multiple single-stage compressor units; inputting the predicted sound pressure values ​​of the multiple single-stage compressor units into the superposition model to obtain the predicted sound pressure values ​​of the multi-stage compressor unit. Through this application, the amplitude, components and sources of noise can be quickly analyzed, which can not only meet the noise prediction requirements of the compressor when it leaves the factory, but also facilitate the rapid resolution of problems on site, and provide technical guidance for parameter optimization in the design stage.

[0005] The defects of the above patents are: 1) limited noise prediction capabilities under dynamic conditions; 2) difficult to accurately distinguish the contributions of different noise sources when faced with complex noise environments, thus affecting the effects of noise control and problem location. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention proposes a compressor casing noise prediction method and system based on an acoustic boundary element model, which can accurately predict the noise level of the compressor casing under complex boundary conditions, thus overcoming the deficiencies of the prior art.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] The compressor casing noise prediction method based on acoustic boundary element model includes:

[0009] Establish a three-dimensional geometric model of the compressor casing;

[0010] Based on the three-dimensional geometric model of the compressor casing, an acoustic boundary element model of the compressor casing is constructed, and the three-dimensional geometric model is discretized into boundary element units;

[0011] Identify the main noise sources inside and outside the compressor and load the identified noise sources into the acoustic boundary element model as boundary conditions;

[0012] Set acoustic boundary conditions according to the actual working environment and material properties of the compressor casing;

[0013] Solve the acoustic boundary element model to calculate the acoustic response of the compressor casing surface;

[0014] The noise of the compressor casing is predicted based on the calculated acoustic response of the compressor casing surface.

[0015] Specifically, the three-dimensional geometric model of the compressor casing is established, including:

[0016] Use CAD software to model the compressor casing. The specific formula is:

[0017]

[0018] Among them, S(u,v) represents the three-dimensional geometric model of the compressor casing, u and v represent the parameters of the three-dimensional geometric model of the compressor casing, and They represent the B-spline basis functions defined in the directions of parameters u and v, respectively. i,j represents the control points of the compressor casing surface, α1 and α2 are the orders of the basis function in the u and v directions respectively, and w i,j Represents and control point P i,j The associated weight, i and j represent the control point index, m and n represent the number of control points;

[0019] The geometric model of the initial design is refined and corrected and optimized based on actual measurement data or simulation results.

[0020] Specifically, the construction of the acoustic boundary element model of the compressor casing includes:

[0021] Based on the three-dimensional geometric model of the compressor casing, the three-dimensional geometric model is discretized to construct the acoustic boundary element model of the compressor casing. The specific formula of the acoustic boundary element model of the compressor casing is:

[0022]

[0023] Where G represents the acoustic boundary element model of the compressor casing, G o represents the oth boundary element unit, and N represents the total number of boundary element units.

[0024] Specifically, the identifying of the main noise sources inside and outside the compressor and loading the identified noise sources as boundary conditions into the acoustic boundary element model include:

[0025] The vibration signal inside the compressor is collected by sensors, and the frequency spectrum of the vibration signal inside the compressor is analyzed through Fourier transform to identify the main mechanical vibration frequency and determine the internal noise source;

[0026] Measure the air flow velocity and pressure at the compressor inlet and outlet, and combine with fluid dynamics simulation to identify the main noise source frequency and determine the external noise source;

[0027] The identified main noise sources inside and outside the compressor are loaded into the acoustic boundary element model as boundary conditions, and the acoustic boundary element model is updated once. The specific formula is:

[0028]

[0029] Among them, p(x) represents the acoustic boundary element model after an update, ρ0 represents the density of the sound propagation medium, c0 represents the speed of sound, Gl(x,y) represents the acoustic Green's function from the boundary point y to the observation point x, represents the normal derivative of the sound pressure at the boundary point y, p(y) represents the sound pressure at the point y on the boundary of the compressor casing, represents the derivative of the Green's function with respect to the normal direction, O represents the normal vector on the surface of the acoustic boundary element model G, and dG(y) represents the integral of the area element on the boundary surface of the acoustic boundary element model G with respect to the boundary point y.

[0030] Specifically, the setting of acoustic boundary conditions includes:

[0031] According to the actual working environment and material characteristics of the compressor casing, the acoustic boundary type of the compressor casing surface is determined, including: acoustic hard boundary and acoustic soft boundary;

[0032] Set the acoustic boundary conditions. The specific formula is:

[0033]

[0034] Among them, β1 and β2 represent weight coefficients, which are adjusted according to the acoustic reflection and absorption characteristics of the compressor casing material;

[0035] Based on the acoustic boundary conditions, the acoustic boundary element model after the first update is updated for the second time. The specific formula is:

[0036]

[0037] Wherein, p'(x) represents the acoustic boundary element model after secondary update, that is, the updated sound pressure at the observation point x.

[0038] Specifically, solving the acoustic boundary element model to calculate the acoustic response of the compressor casing surface includes:

[0039] The acoustic boundary element model after the second update is solved to obtain the acoustic response of the compressor casing surface. The specific formula is:

[0040]

[0041] Where q(x) represents the acoustic response at the observation point x of the compressor casing, L(y a ) indicates that at the boundary point y a The flow rate of the sound wave at a represents the area of ​​the ath boundary cell, and A represents the number of boundary cells.

[0042] Specifically, the predicting of the noise of the compressor casing includes:

[0043] Based on the calculated acoustic response of the compressor casing surface, the noise of the compressor casing at the observation point x is predicted. The specific formula is:

[0044]

[0045] Among them, L p represents the predicted noise of the compressor casing at the observation point x, lg 10 () represents a logarithmic function with a base of 10, and p0 represents the reference sound pressure.

[0046] A compressor casing noise prediction system based on an acoustic boundary element model, used to implement the compressor casing noise prediction method based on an acoustic boundary element model, comprising: a geometric modeling module, a boundary discretization module, a sound source loading module, a condition setting module, a model solving module and a noise prediction module;

[0047] The geometric modeling module is used to establish a three-dimensional geometric model of the compressor casing;

[0048] The boundary discretization module is used to construct an acoustic boundary element model of the compressor casing based on the three-dimensional geometric model of the compressor casing, and discretize the three-dimensional geometric model into boundary element units;

[0049] The sound source loading module is used to identify the main noise sources inside and outside the compressor, and load the identified noise sources into the acoustic boundary element model as boundary conditions;

[0050] The condition setting module is used to set the acoustic boundary conditions according to the actual working environment and material properties of the compressor casing;

[0051] The model solving module is used to solve the acoustic boundary element model and calculate the acoustic response of the compressor casing surface;

[0052] The noise prediction module is used to predict the noise of the compressor casing based on the calculated acoustic response of the compressor casing surface.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] 1. The present invention proposes a compressor casing noise prediction method based on the acoustic boundary element model. The method based on the acoustic boundary element model can accurately simulate the sound field distribution and noise radiation characteristics of the compressor casing. It has higher prediction accuracy than traditional methods and takes into account the complex geometric shape and material properties of the casing to more accurately locate and quantify the noise source.

[0055] 2. The present invention proposes a compressor casing noise prediction method based on the acoustic boundary element model. Compared with other numerical methods, the boundary element method can significantly reduce the consumption of computing resources and improve computing efficiency by reducing the dimension of the solution area when dealing with external sound field problems.

[0056] 3. The present invention proposes a compressor casing noise prediction method based on the acoustic boundary element model, which is suitable for compressors of different types and sizes. By adjusting the model parameters, the noise level of the compressor can be optimized in the design stage, thereby realizing a customized noise control solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A flow chart of a compressor casing noise prediction method based on an acoustic boundary element model provided by the present invention;

[0058] Figure 2 This is a diagram of the architecture of the compressor casing noise prediction system based on the acoustic boundary element model provided by the present invention. DETAILED DESCRIPTION

[0059] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, in the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "No. 1", "No. 2" and "No. 3" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. The present invention is further explained below in conjunction with specific embodiments.

[0060] Example 1

[0061] See also Figure 1 The present invention provides an embodiment: a compressor casing noise prediction method based on an acoustic boundary element model, comprising the following specific steps:

[0062] Step S1: establishing a three-dimensional geometric model of the compressor casing;

[0063] The specific steps of step S1 are:

[0064] Step S101: Use CAD software to accurately model the compressor casing. The specific formula is:

[0065]

[0066] Among them, S(u,v) represents the three-dimensional geometric model of the compressor casing, u and v represent the parameters of the three-dimensional geometric model of the compressor casing, and by adjusting the values ​​of the parameters u and v, different points on the surface can be obtained. and Respectively represent the B-spline basis functions defined in the direction of parameters u and v, which determine the smoothness and shape of the surface, P i,j represents the control points of the compressor casing surface. α1 and α2 are the orders of the basis function in the u and v directions, that is, the degree of the surface function. A higher order can generate a smoother and more complex surface. i,j Represents and control point P i,j The associated weights, i and j represent the control point index, i is the control point index corresponding to the parameter u direction, j is the control point index corresponding to the parameter v direction, m and n represent the number of control points, n represents the number of control points in the parameter u direction minus 1, that is, the total number of control points in the u direction is n+1, m represents the number of control points in the parameter v direction minus 1, that is, the total number of control points in the v direction is m+1;

[0067] In this embodiment, the complex geometric shape of the compressor casing can be accurately described, including details such as fillets, depressions, and protrusions. This accuracy is much higher than that of traditional polygonal mesh modeling methods, especially when dealing with complex geometries and surface transitions. In order to further improve the accuracy of the model, this method introduces adaptive refinement technology. By introducing a local refinement strategy, it is possible to perform refinement in important geometric feature areas (such as sharply changing surfaces or near boundaries) while keeping the global computational complexity controllable, thereby improving the modeling accuracy of these areas.

[0068] Step S102: Refine the geometric model of the initial design, and calibrate and optimize the geometric model according to actual measurement data or simulation results, such as bolt holes, support ribs, etc., to ensure that it can accurately reflect the actual shape and structural characteristics of the compressor casing.

[0069] Step S2: constructing an acoustic boundary element model of the compressor casing based on the three-dimensional geometric model of the compressor casing, and discretizing the three-dimensional geometric model into boundary element units;

[0070] Construct an acoustic boundary element model of the compressor casing, including:

[0071] Based on the three-dimensional geometric model of the compressor casing, the three-dimensional geometric model is discretized to construct the acoustic boundary element model of the compressor casing. The specific formula of the acoustic boundary element model of the compressor casing is:

[0072]

[0073] Where G represents the acoustic boundary element model of the compressor casing, which is a closed surface in three-dimensional space, representing the outer surface of the entire geometric model and used for acoustic field analysis. o represents the oth boundary element unit, representing a part of the boundary after discretization, and N represents the total number of boundary element units, that is, the number of boundary element units after the entire geometric model is discretized.

[0074] Through the steps of discretization and unitization, complex geometric shapes and boundary conditions can be described more accurately, significantly improving the calculation accuracy of the acoustic boundary element model. Compared with traditional methods, the discretization technology using polygons or surface patches enables the model to maintain high accuracy and effectively capture detailed features when dealing with complex geometric shapes.

[0075] Step S3: identifying the main noise sources inside and outside the compressor, and loading the identified noise sources into the acoustic boundary element model as boundary conditions;

[0076] The specific steps of step S3 are:

[0077] Step S301: using a sensor to collect vibration signals inside the compressor, analyzing the frequency spectrum of the vibration signals inside the compressor through Fourier transform, identifying the main mechanical vibration frequency, and determining the internal noise source;

[0078] Step S302: measuring the air flow velocity and pressure at the compressor inlet and outlet, identifying the main noise source frequency and determining the external noise source in combination with fluid dynamics simulation;

[0079] Step S303: The identified main noise sources inside and outside the compressor are loaded into the acoustic boundary element model as boundary conditions, and the acoustic boundary element model is updated. The specific formula is:

[0080]

[0081] Among them, p(x) represents the acoustic boundary element model after an update, that is, the initial sound pressure at the observation point x, which is an important physical quantity in the sound field and is used to measure the intensity of the sound wave. ρ0 represents the density of the sound propagation medium, c0 represents the speed of sound, and Gl(x,y) represents the acoustic Green's function from the boundary point y to the observation point x. The Green's function is a key function in the sound field analysis and is used to calculate the distribution of sound pressure. It contains the attenuation and phase change information of the sound wave on different paths. It represents the normal derivative of the sound pressure at the boundary point y, reflecting the rate of change of the sound pressure on the boundary. The normal derivative is an important part of the boundary condition, which is used to describe the influence of the boundary on the sound field, especially on the boundary where the sound source exists. represents the derivative of the Green's function with respect to the normal direction, O represents the normal vector on the surface of the acoustic boundary element model G, the normal vector defines the calculation direction of the derivative of the sound pressure p(y) and the Green's function Gl(x,y) at the boundary point y, p(y) represents the sound pressure at the boundary point y of the compressor casing, dG(y) represents the integral of the small area elements on the boundary surface of the acoustic boundary element model G with respect to the boundary point y.

[0082] In this embodiment, sound pressure is directly related to the intensity and propagation characteristics of noise, and is the main target of noise analysis and prediction. In the acoustic boundary element method, the formula calculates the sound pressure p(x) at the observation point x, combines the sound pressure p(y) on the boundary and the normal derivative of the Green's function Gl(x, y), and integrates it over the entire surface of the acoustic boundary element model G. The final sound pressure value is determined by summing the contribution of each point on the boundary. The normal vector O and the boundary integral G(y) are key factors that determine how sound waves propagate, reflect on the boundary and affect the sound pressure at the observation point.

[0083] Step S4: setting acoustic boundary conditions according to the actual working environment and material properties of the compressor casing;

[0084] The specific steps of step S4 are:

[0085] Step S401: determining the acoustic boundary type of the compressor casing surface according to the actual working environment and material properties of the compressor casing, including an acoustic hard boundary and an acoustic soft boundary;

[0086] Step S402: Set the acoustic boundary conditions, the specific formula is:

[0087]

[0088] Among them, β1 and β2 represent weight coefficients, which are adjusted according to the acoustic reflection and absorption characteristics of the compressor casing material;

[0089] Step S403: Based on the acoustic boundary conditions, the acoustic boundary element model after the first update is updated for the second time. The specific formula is:

[0090]

[0091] Wherein, p'(x) represents the acoustic boundary element model after secondary update, that is, the updated sound pressure at the observation point x.

[0092] Step S5: solving the acoustic boundary element model to calculate the acoustic response of the compressor casing surface;

[0093] Solve the acoustic boundary element model to calculate the acoustic response of the compressor casing surface, including:

[0094] The acoustic boundary element model after the second update is solved to obtain the acoustic response of the compressor casing surface. The specific formula is:

[0095]

[0096] Where q(x) represents the acoustic response at the observation point x of the compressor casing, that is, the final sound pressure at the observation point x, L(y a ) indicates that at the boundary point y a The flow of the sound wave at the point reflects the energy transfer of the sound wave at that point. It is related to the sound pressure and the material properties of the boundary point. a Represents the area of ​​the ath boundary element, that is, the sum of these small areas on the entire boundary surface is used to calculate the total sound pressure contribution from all sound source points y to the observation point x on the boundary surface of the acoustic boundary element model G. A represents the number of boundary elements.

[0097] The sound pressure contributions of all boundary units are accumulated through integral equations to obtain the sound pressure distribution of each observation point on the compressor casing surface. The fast multipole method can effectively reduce the amount of calculation and adapt to high-precision acoustic analysis of complex geometric structures. Finally, the model is verified by experimental data or actual measurement results to ensure the reliability of the prediction results.

[0098] Step S6: predicting the noise of the compressor casing based on the calculated acoustic response of the compressor casing surface.

[0099] Predict the noise of the compressor casing, including:

[0100] Based on the calculated acoustic response of the compressor casing surface, the noise of the compressor casing at the observation point x is predicted. The specific formula is:

[0101]

[0102] Among them, L p represents the predicted noise of the compressor casing at the observation point x, lg 10 () represents a logarithmic function with a base of 10, p0 represents the reference sound pressure, which is generally 20μPa. This value corresponds to the minimum sound pressure that can be heard by the human ear, so it is often used as a reference benchmark in sound pressure level calculations.

[0103] The calculated sound pressure level and sound power level can be used to draw noise field distribution maps around the compressor. These distribution maps can intuitively show the propagation path and intensity distribution of noise in space, which helps to identify the main location of noise sources and noise transmission pathways.

[0104] In addition, according to the noise field distribution under different working conditions, the noise level of the compressor in various working environments can be evaluated and corresponding noise reduction measures can be formulated. By comparing the noise field distribution of different design schemes, the design of the compressor can be optimized, thereby reducing noise pollution and improving the acoustic performance of the equipment.

[0105] In this embodiment, 10log 10 It reflects the conversion relationship between sound pressure and sound pressure level. By performing 20 times logarithmic processing on the sound pressure, the physical value of the sound pressure can be converted into an easy-to-interpret scalar level value, usually in decibels (dB). The calculation of the decibel value allows the sound pressure levels of different sound sources to be directly compared.

[0106] Example 2

[0107] See also Figure 2, another embodiment provided by the present invention: a compressor casing noise prediction system based on an acoustic boundary element model, comprising: a geometric modeling module, a boundary discretization module, a sound source loading module, a condition setting module, a model solving module and a noise prediction module;

[0108] The geometric modeling module is used to establish a three-dimensional geometric model of the compressor casing;

[0109] The boundary discretization module is used to construct an acoustic boundary element model of the compressor casing based on the three-dimensional geometric model of the compressor casing, and discretize the three-dimensional geometric model into boundary element units;

[0110] The sound source loading module is used to identify the main noise sources inside and outside the compressor, and load the identified noise sources into the acoustic boundary element model as boundary conditions;

[0111] The condition setting module is used to set the acoustic boundary conditions according to the actual working environment and material properties of the compressor casing;

[0112] The model solving module is used to solve the acoustic boundary element model and calculate the acoustic response of the compressor casing surface;

[0113] The noise prediction module is used to predict the noise of the compressor casing based on the calculated acoustic response of the compressor casing surface.

[0114] In addition, the parts of the above-mentioned technical solutions provided in the embodiments of the present application that are consistent with the implementation principles of the corresponding technical solutions in the prior art are not described in detail to avoid excessive redundancy.

[0115] The specific implementation modes as described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation mode of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for predicting compressor casing noise based on acoustic boundary element model, characterized in that: include: Establish a three-dimensional geometric model of the compressor casing; Based on the three-dimensional geometric model of the compressor casing, an acoustic boundary element model of the compressor casing is constructed, and the three-dimensional geometric model is discretized into boundary element units; Identify the main noise sources inside and outside the compressor and load the identified noise sources into the acoustic boundary element model as boundary conditions; Set acoustic boundary conditions according to the actual working environment and material properties of the compressor casing; Solve the acoustic boundary element model to calculate the acoustic response of the compressor casing surface; The noise of the compressor casing is predicted based on the calculated acoustic response of the compressor casing surface.

2. The compressor casing noise prediction method based on acoustic boundary element model according to claim 1, characterized in that: The three-dimensional geometric model of the compressor casing is established, comprising: Use CAD software to model the compressor casing. The specific formula is: Among them, S(u,v) represents the three-dimensional geometric model of the compressor casing, u and v represent the parameters of the three-dimensional geometric model of the compressor casing, and They represent the B-spline basis functions defined in the directions of parameters u and v, respectively. i,j represents the control points of the compressor casing surface, α1 and α2 are the orders of the basis function in the u and v directions respectively, and w i,j Represents and control point P i,j The associated weight, i and j represent the control point index, m and n represent the number of control points; The geometric model of the initial design is refined and corrected and optimized based on actual measurement data or simulation results.

3. The compressor casing noise prediction method based on acoustic boundary element model according to claim 2, characterized in that: The construction of the acoustic boundary element model of the compressor casing comprises: Based on the three-dimensional geometric model of the compressor casing, the three-dimensional geometric model is discretized to construct the acoustic boundary element model of the compressor casing. The specific formula of the acoustic boundary element model of the compressor casing is: Where G represents the acoustic boundary element model of the compressor casing, G o represents the oth boundary element unit, and N represents the total number of boundary element units.

4. The compressor casing noise prediction method based on acoustic boundary element model according to claim 3, characterized in that: The step of identifying the main noise sources inside and outside the compressor and loading the identified noise sources as boundary conditions into the acoustic boundary element model includes: The vibration signal inside the compressor is collected by sensors, and the frequency spectrum of the vibration signal inside the compressor is analyzed through Fourier transform to identify the main mechanical vibration frequency and determine the internal noise source; Measure the air flow velocity and pressure at the compressor inlet and outlet, and identify the main noise source frequency and external noise source by combining fluid dynamics simulation; The identified main noise sources inside and outside the compressor are loaded into the acoustic boundary element model as boundary conditions, and the acoustic boundary element model is updated once. The specific formula is: Among them, p(x) represents the acoustic boundary element model after an update, ρ0 represents the density of the sound propagation medium, c0 represents the speed of sound, Gl(x,y) represents the acoustic Green's function from the boundary point y to the observation point x, represents the normal derivative of the sound pressure at the boundary point y, p(y) represents the sound pressure at the point y on the boundary of the compressor casing, represents the derivative of the Green's function with respect to the normal direction, O represents the normal vector on the surface of the acoustic boundary element model G, and dG(y) represents the integral of the area element on the boundary surface of the acoustic boundary element model G with respect to the boundary point y.

5. The compressor casing noise prediction method based on acoustic boundary element model according to claim 4, characterized in that: The setting of acoustic boundary conditions includes: According to the actual working environment and material characteristics of the compressor casing, the acoustic boundary type of the compressor casing surface is determined, including: acoustic hard boundary and acoustic soft boundary; Set the acoustic boundary conditions. The specific formula is: Among them, β1 and β2 represent weight coefficients, which are adjusted according to the acoustic reflection and absorption characteristics of the compressor casing material; Based on the acoustic boundary conditions, the acoustic boundary element model after the first update is updated for the second time. The specific formula is: Wherein, p'(x) represents the acoustic boundary element model after secondary update, that is, the updated sound pressure at the observation point x.

6. The compressor casing noise prediction method based on acoustic boundary element model according to claim 5, characterized in that: The method of solving the acoustic boundary element model and calculating the acoustic response of the compressor casing surface includes: The acoustic boundary element model after the second update is solved to obtain the acoustic response of the compressor casing surface. The specific formula is: Where q(x) represents the acoustic response at the observation point x of the compressor casing, L(y a ) indicates that at the boundary point y a The flow rate of the sound wave at a represents the area of ​​the ath boundary cell, and A represents the number of boundary cells.

7. The compressor casing noise prediction method based on acoustic boundary element model according to claim 6, characterized in that: The predicting of the noise of the compressor casing comprises: Based on the calculated acoustic response of the compressor casing surface, the noise of the compressor casing at the observation point x is predicted. The specific formula is: Among them, L p represents the predicted noise of the compressor casing at the observation point x, lg 10 () represents a logarithmic function with a base of 10, and p0 represents the reference sound pressure.

8. A compressor casing noise prediction system based on an acoustic boundary element model, used to implement the compressor casing noise prediction method based on an acoustic boundary element model as described in any one of claims 1 to 7, characterized in that: include: Geometric modeling module, boundary discretization module, sound source loading module, condition setting module, model solving module and noise prediction module; The geometric modeling module is used to establish a three-dimensional geometric model of the compressor casing; The boundary discretization module is used to construct an acoustic boundary element model of the compressor casing based on the three-dimensional geometric model of the compressor casing, and discretize the three-dimensional geometric model into boundary element units; The sound source loading module is used to identify the main noise sources inside and outside the compressor, and load the identified noise sources into the acoustic boundary element model as boundary conditions; The condition setting module is used to set the acoustic boundary conditions according to the actual working environment and material properties of the compressor casing; The model solving module is used to solve the acoustic boundary element model and calculate the acoustic response of the compressor casing surface; The noise prediction module is used to predict the noise of the compressor casing based on the calculated acoustic response of the compressor casing surface.

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