Aerodynamic noise determining method and apparatus

Abstract

An aerodynamic noise determining method and apparatus, relating to the technical field of noise, and used for implementing rapid aerodynamic noise prediction. For the problems of poor precision and low efficiency of existing aerodynamic noise prediction, an aerodynamic noise determining method is provided. Aerodynamic sound field computation implemented based on an unsteady-state flow field is converted into noise index computation under a steady-state flow field and linear transformation between a noise index and a noise sound power level, thereby achieving the objective of sound field-free computation. Thus, the problems of a large computation amount, low efficiency, and unsuitability for noise prediction for devices having complex working conditions such as a motor caused by sound field computation are avoided, and the requirement for analyzing and controlling aerodynamic noise of rotating machines in actual engineering can be better satisfied.

Description

Method and device for determining aerodynamic noise

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on October 31, 2023, with application number 202311433416.8 and invention name “A method and device for determining aerodynamic noise”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of noise technology, and in particular to a method and device for determining aerodynamic noise. Background Art

[0003] Aerodynamic noise is a significant component of the noise generated by rotating machinery, such as motors. Current noise reduction measures for motors and other equipment primarily rely on testing and combining technical expertise to identify the primary noise source, then developing appropriate remediation measures for that source.

[0004] However, this approach lacks specific analysis and research on aerodynamic noise characteristics. Common aerodynamic noise calculation methods often rely on unsteady computational fluid fields to calculate the aerodynamic sound field, thereby deriving noise through simulation. However, this approach is unsuitable for complex engineering models, such as motors, which have multiple operating conditions (e.g., those distinguished by motor speed). This approach suffers from numerous issues, including poor computational convergence, high computational effort, low computational efficiency, long design cycles, and high costs.

[0005] Therefore, technicians in this field are in urgent need of a method for determining aerodynamic noise, which can realize the prediction of aerodynamic noise at multiple speeds of the motor model and meet the accuracy requirements of actual engineering applications.

[0006] Summary of the Invention

[0007] The purpose of this application is to provide a method and device for determining aerodynamic noise, so as to realize the aerodynamic noise prediction of a motor model at multiple speeds and meet the accuracy requirements of actual engineering applications.

[0008] To solve the above technical problems, the present application provides a method for determining aerodynamic noise, comprising:

[0009] Establish a flow field calculation domain to simulate the current steady-state flow field of the motor and determine the aerodynamic characteristic quantities of the steady-state flow field;

[0010] Determine the noise index based on aerodynamic characteristics;

[0011] Substitute the noise index into the pre-established quantitative relationship equation to determine the noise sound power level;

[0012] The establishment of the quantitative relationship equation includes:

[0013] Determine the aerodynamic characteristics of the motor at different speeds, and determine the noise index corresponding to each speed based on each group of aerodynamic characteristics;

[0014] Measure the noise sound power level of the motor at various speeds;

[0015] The linear correlation analysis of the noise index and noise sound power level corresponding to each speed is performed according to the least square method to determine the linear relationship equation between the noise index and the noise sound power level as a quantitative relationship equation.

[0016] On the other hand, noise indicators determined based on aerodynamic characteristics include:

[0017] The airflow sound source obtained from the physical quantity or combination of physical quantities in the aerodynamic characteristic quantity is spatially integrated by the finite volume method to obtain the sound source intensity index; and the noise index is then determined based on the sound source intensity index.

[0018] On the other hand, the airflow sound source is the divergence, absolute value or kinetic energy of a certain physical quantity or combination of physical quantities in the aerodynamic characteristic quantities.

[0019] On the other hand, aerodynamic characteristics include: vorticity and velocity; the airflow sound source is the divergence of the combination of vorticity and velocity;

[0020] Accordingly, the noise index determined based on aerodynamic characteristics includes:

[0021] Determine the sound source intensity index of the airflow sound source according to the first formula, and determine the noise index according to the sound source intensity index;

[0022] Among them, the first formula is:

[0023] S n Indicates the intensity index of the sound source; is the Hamiltonian operator; the dot represents the dot product between vectors; represents the vorticity vector; represents the velocity vector; dV represents the spatial integral.

[0024] On the other hand, aerodynamic characteristic quantities include: vorticity or velocity; the airflow sound source is the divergence of vorticity or velocity;

[0025] Accordingly, the noise index determined based on aerodynamic characteristics includes:

[0026] Determine the sound source intensity index of the airflow sound source according to the second formula, and determine the noise index according to the sound source intensity index;

[0027] Among them, the second formula is:

[0028] S nIndicates the intensity index of the sound source; is the Hamiltonian operator; the dot represents the dot product between vectors; represents the vorticity vector; dV represents the spatial integral;

[0029] Alternatively, determining the noise index based on aerodynamic characteristic quantities includes:

[0030] Determine the sound source intensity index of the airflow sound source according to the third formula, and determine the noise index according to the sound source intensity index;

[0031] Among them, the third formula is:

[0032] Represents the velocity vector.

[0033] On the other hand, aerodynamic characteristic quantities include: vorticity, velocity or pressure; the airflow sound source is the absolute value of vorticity, velocity or pressure;

[0034] Accordingly, the noise index determined based on aerodynamic characteristics includes:

[0035] Determine the sound source intensity index of the airflow sound source according to the fourth formula, and determine the noise index according to the sound source intensity index;

[0036] Among them, the fourth formula is: S n =∫|P|dV;

[0037] S n Indicates the sound source intensity index; P indicates pressure; dV indicates spatial integration;

[0038] Alternatively, determining the noise index based on aerodynamic characteristic quantities includes:

[0039] Determine the sound source intensity index of the airflow sound source according to the fifth formula, and determine the noise index according to the sound source intensity index;

[0040] Among them, the fifth formula is:

[0041] represents the velocity vector;

[0042] Alternatively, determining the noise index based on aerodynamic characteristic quantities includes:

[0043] Determine the sound source intensity index of the airflow sound source according to the sixth formula, and determine the noise index according to the sound source intensity index;

[0044] Among them, the sixth formula is:

[0045] represents the vorticity vector.

[0046] On the other hand, aerodynamic characteristic quantities include: vorticity or velocity; the airflow sound source is the kinetic energy of vorticity or velocity;

[0047] Accordingly, the noise index determined based on aerodynamic characteristics includes:

[0048] Determine the sound source intensity index of the airflow sound source according to the seventh formula, and determine the noise index according to the sound source intensity index;

[0049] Among them, the seventh formula is:

[0050] S n Indicates the intensity index of the sound source; represents the velocity vector; dV represents the spatial integral;

[0051] Alternatively, determining the noise index based on aerodynamic characteristic quantities includes:

[0052] Determine the sound source intensity index of the airflow sound source according to the eighth formula, and determine the noise index according to the sound source intensity index;

[0053] Among them, the eighth formula is:

[0054] represents the vorticity vector.

[0055] On the other hand, noise indicators determined based on aerodynamic characteristics include:

[0056] The noise index is determined comprehensively based on all physical quantities in the aerodynamic characteristic quantities.

[0057] To solve the above technical problems, the present application further provides an aerodynamic noise determination device, comprising:

[0058] The flow field simulation module is used to establish a flow field calculation domain to simulate the current steady-state flow field of the motor and determine the aerodynamic characteristic quantities of the steady-state flow field;

[0059] An index determination module, used for determining a noise index according to aerodynamic characteristic quantities;

[0060] A noise prediction module is used to substitute the noise index into a pre-established quantitative relationship equation to determine the noise sound power level;

[0061] The establishment of the quantitative relationship equation is achieved through an equation establishment module, which includes:

[0062] A parameter simulation unit is used to determine the aerodynamic characteristics of the motor at different speeds, and to determine the noise index corresponding to each speed based on each set of aerodynamic characteristics;

[0063] Noise measurement unit, used to measure the noise sound power level of the motor at various speeds;

[0064] The linear analysis unit is used to perform linear correlation analysis on the noise index and the noise sound power level corresponding to each speed according to the least square method, so as to determine the linear relationship equation between the noise index and the noise sound power level as a quantitative relationship equation.

[0065] This application provides a method for determining aerodynamic noise. By pre-establishing a quantitative relationship equation for the linear relationship between the noise index calculated under a steady-state flow field and the noise sound power level, which reflects the noise level, the problem of calculating the noise sound power level based on an unsteady flow field is converted into the problem of calculating the noise index under a steady-state flow field. Furthermore, when noise prediction is actually needed, the noise index can be directly calculated through steady-state flow field calculations, and the noise sound power level can be determined based on the noise index and the pre-established quantitative relationship equation, thus achieving indirect noise prediction. Because this solution no longer requires calculations under an unsteady flow field, but instead uses calculations under a steady-state flow field, it achieves higher computational accuracy, efficiency, and better convergence. Furthermore, the quantitative relationship equation established based on data from multi-speed motor operating conditions makes this solution well suited for predicting aerodynamic noise under conditions such as motors at different speeds. This allows for predicting aerodynamic noise related to rotating machinery with complex operating conditions, such as motors. It is also applicable to scenarios such as aerodynamic optimization design of external flow fields, where traditional aerodynamic noise prediction using unsteady flow field calculations is difficult, better meeting the needs of technicians for analyzing and controlling the aerodynamic noise of rotating machinery.

[0066] The aerodynamic noise determination device provided in this application corresponds to the above method and has the same effect as above. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0068] FIG1 is a flow chart of a method for determining aerodynamic noise provided by the present invention;

[0069] FIG2 is a structural diagram of an aerodynamic noise determination device provided by the present invention. DETAILED DESCRIPTION

[0070] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0071] The core of this application is to provide a method and device for determining aerodynamic noise.

[0072] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0073] Currently, before noise reduction is implemented on a device, it is necessary to first detect the noise of the device so that targeted improvement plans can be made based on the noise situation. Currently, there are three main solutions for noise detection:

[0074] 1. Separation calculation method based on unsteady-state simulation;

[0075] This method uses an unsteady computational fluid field to calculate the aerodynamic acoustic field, achieving noise prediction through simulation. However, this approach often suffers from poor convergence, high computational effort, and long computational time, making it difficult to apply to equipment with complex and variable operating conditions, such as motors.

[0076] 2. Coupling calculation method based on steady-state simulation;

[0077] This method requires less computation than Method 1, but it also suffers from the problem of large errors when used for the internal flow field of a high-speed rotating motor dominated by the dynamic domain. It is also not suitable for the industrial sector to measure and predict the noise of the motor under all working conditions and multiple speeds.

[0078] 3. Semi-empirical method based on experiment;

[0079] This involves testing the equipment and collecting noise data according to noise testing standards, followed by subsequent noise prediction using empirical formulas. This experimental approach is often resource-intensive and has limitations, such as an inability to capture changes in internal flow details after design parameter changes. Empirical formulas are only applicable to simple fan blade structures and have limited accuracy in predicting motor noise.

[0080] Therefore, there is an urgent need for a new rapid noise prediction method to adapt to the detection of rotating machinery noise with complex working conditions such as motors in actual industrial production.

[0081] Based on this, the present application provides a method for determining aerodynamic noise, as shown in FIG1 , comprising:

[0082] S11: establishing a flow field calculation domain to simulate the current steady-state flow field of the motor and determining the aerodynamic characteristic quantities of the steady-state flow field;

[0083] S12: Determine the noise index according to the aerodynamic characteristic quantity;

[0084] S13: Substitute the noise index into the pre-established quantitative relationship equation to determine the noise sound power level;

[0085] The establishment of the quantitative relationship equation includes:

[0086] S21: determining aerodynamic characteristic quantities of the motor at different speeds, and determining a noise index corresponding to each speed based on each group of aerodynamic characteristic quantities;

[0087] S22: Measure the noise power level of the motor at each speed;

[0088] S23: performing a linear correlation analysis on the noise index and the noise sound power level corresponding to each speed according to the least square method to determine a linear relationship equation between the noise index and the noise sound power level as a quantitative relationship equation.

[0089] It should be noted that the aerodynamic noise determination method provided in this application can be divided into two parts: a noise prediction method (corresponding to steps S11 to S13) and an equation establishment method (corresponding to steps S21 to S23). In the actual engineering application of noise prediction, the equation establishment method process for the same device only needs to be performed once. Even if the device is subsequently modified, optimized, or the operating conditions change (for example, the motor speed changes), the previously established quantitative relationship equation can still be used to achieve noise prediction for the device through the noise prediction method process. That is, for multiple noise prediction scenarios of the same device, the equation establishment method only needs to be executed once, while the noise prediction method needs to be executed each time noise prediction is made.

[0090] Therefore, to further illustrate the aerodynamic noise determination method provided in this application, the subsequent description will be divided into two parts: the noise prediction method and the equation establishment method.

[0091] First, regarding the noise prediction method (steps S11 to S13), step S11 is a method of using the flow field calculation domain to simulate the steady-state flow field of the device under test. As can be seen from the above-mentioned traditional solutions for noise prediction, the advantages of simulating the steady-state flow field over simulating the unsteady flow field are low computational complexity, good convergence, and high computational efficiency. However, it is difficult to directly and accurately obtain the aerodynamic noise of the flow field dominated by the dynamic domain through steady-state flow field simulation (in actual engineering, the noise sound power level SPL is usually used to represent the magnitude of the aerodynamic noise). Therefore, step S11 turns to convergent calculation of the aerodynamic characteristic quantities of the steady-state flow field.

[0092] In addition, this embodiment does not limit the simulation method of the steady-state flow field, but a more commonly used solution is Computational Fluid Dynamics (CFD) simulation.

[0093] It should be noted that the present application does not limit the specific implementation form of the aerodynamic characteristic quantity in step S11, and it can include any physical quantity related to aerodynamic characteristics simulated by the steady-state flow field simulation, for example, it can include but not be limited to: pressure (P), velocity (u), vorticity (ω) and other parameters. Then, in step S12, the aerodynamic characteristic quantity obtained by simulating the steady-state flow field in step S11 is converted into a unique parameter standard for characterizing aerodynamic noise, namely the above-mentioned noise index lgS n Among them, lg represents the noise index, specifically the sound source intensity index S n That is, step S12 specifically calculates the sound source intensity index S by simulating the aerodynamic characteristics of the steady-state flow field in step S11. n , and then the sound source intensity index S n Perform natural logarithmic calculation to obtain the noise index lgS n .

[0094] Determine the noise index lgS at different speeds of the equipment n Then, step S13 converts the noise index lgS into the quantitative relationship equation obtained in advance by the equation establishment method (steps S21 to S23). n It is converted into the sound power level SPL which directly reflects the size of the aerodynamic noise, so as to quickly determine the aerodynamic noise of the equipment under test.

[0095] It is particularly important to note that the noise sound power level SPL cannot be directly calculated using a steady-state flow field, and the accuracy of calculating the noise sound power level SPL of rotating machinery with complex working conditions such as motors using unsteady flow fields cannot meet the actual engineering needs. Therefore, this method converts the problem of calculating the noise sound power level SPL under unsteady flow fields into calculating the noise index lgS under steady-state flow fields. n The problem is then solved by the noise index lgS n The calculation of noise sound power level SPL is indirectly realized to meet the needs of actual engineering aerodynamic noise prediction in terms of calculation implementation difficulty and accuracy.

[0096] On the other hand, for the equation establishment method (steps S21 to S23), it is not difficult to see that the most important factor affecting the accuracy of the noise prediction method in predicting aerodynamic noise is the accuracy of the quantitative relationship equation determined in this method.

[0097] Regarding step S21, since the aerodynamic noise determination method provided by this application also aims to be applicable to noise prediction of equipment with different speeds, such as motors, in step S21, it is necessary to predict the steady-state flow field of the equipment under test under different speed conditions to obtain the aerodynamic characteristics of the equipment under test under different speed conditions. And based on the same method as in step S12 above, the aerodynamic characteristics are converted into the corresponding noise index lgS n .

[0098] In step S22, because simulation and other methods are often inaccurate when used to detect aerodynamic noise in complex equipment such as motors, this step can employ actual testing to determine the noise sound power level (SPL) of the device under test at different speeds. Specifically, a test environment is established according to aerodynamic noise detection standards, the device under test is placed in the test environment, and the aerodynamic noise of the device under test at different speeds is collected. This determines the noise sound power level (SPL) at different speeds.

[0099] It should be noted that the above clearly states that this method only needs to be executed once for the same device under test. Therefore, although a test environment is required in step S22 to detect actual aerodynamic noise, this part of the process can be performed in advance before the device leaves the factory. When the user uses the device in an actual project and needs to predict aerodynamic noise, this step does not need to be repeated, thus not adding excessive difficulty and cost to the actual implementation of aerodynamic noise prediction.

[0100] For step S23, the noise index lgS of the device under test at different speeds is n The noise power level SPL and the noise power level SPL are known, so the noise index lgS at different speeds is calculated. n Perform linear correlation analysis on the noise power level SPL to determine the noise index lgS n The linear relationship equation between the noise sound power level SPL. The linear relationship equation determined here is the quantitative relationship equation required in the noise prediction method, which can adapt to the needs of the equipment under test with various speed conditions, and the noise index lgS calculated based on the steady-state flow field simulation n It is converted into the noise sound power level SPL, which is difficult to directly simulate and calculate, thereby realizing the rapid prediction of aerodynamic noise of rotating machinery such as motors.

[0101] It should also be noted that the least squares method used in step S23 is only a preferred implementation scheme and can be replaced by other linear correlation analysis methods depending on actual implementation needs.

[0102] The linear relationship equation can be expressed as: SPL = A × lgSn -B;

[0103] Among them, A is the slope of the linear relationship equation, and B is the intercept of the linear relationship equation.

[0104] Use the least squares method to analyze the noise index lgS n The linear relationship between the noise sound power level SPL and the noise level is guaranteed to be accurate and can meet the actual engineering needs. At the same time, the calculation amount is small, which is conducive to the rapid prediction of aerodynamic noise.

[0105] As can be seen from the above, the present application provides a method for determining aerodynamic noise, which calculates the corresponding aerodynamic characteristic quantity and noise index lgS by pre-establishing the steady-state flow field of the device under test at different speeds. n ; Then, by actually setting up the test environment, collect the noise sound power level SPL of the equipment under test at different speed conditions; and then analyze the noise index lgS at different speeds n The linear relationship between the noise sound power level SPL and the noise power level SPL is obtained, and a quantitative relationship equation is obtained. From then on, when aerodynamic noise prediction is needed in the actual engineering application of the equipment under test, the noise index lgS of the equipment under test at this moment can be obtained through steady-state flow field simulation calculation. n , the noise sound power level SPL is directly obtained through a predetermined quantitative relationship.

[0106] The core of this method is to achieve the noise index lgS n The linear conversion between the noise sound power level SPL and the noise sound power level SPL in actual engineering is difficult to directly calculate through simulation, which is converted into a steady-state flow field simulation noise index lgS with smaller calculation amount and higher convergence. n The noise index lgS is achieved through a quantitative relationship equation that can be adapted to different speed conditions. n The conversion between the sound power level (SPL) and the noise level can quickly predict the aerodynamic noise of rotating machinery with various speed conditions such as motors, as well as complex working conditions such as external flow fields, providing data support for technicians to subsequently analyze and control the aerodynamic noise of motors and improve the performance of motors.

[0107] As can be seen from the above embodiments, whether it is the actual noise prediction method process for determining aerodynamic noise or the pre-executed equation establishment method process for establishing a quantitative relationship equation, it involves determining the noise index lgS based on the aerodynamic characteristic quantity. n process.

[0108] In the above embodiment, the general process is described as determining the sound source intensity index S by aerodynamic characteristics. n , followed by the sound source intensity index S n Determine the noise index lgSn . By the sound source intensity index S n Determine the noise index lgS n The steps are known, find the sound source intensity index S n The natural logarithm of the noise index lgS can be obtained n However, how to determine the sound source intensity index S based on the aerodynamic characteristics n The above embodiment does not make a strict limitation, and this embodiment provides a possible implementation scheme for this purpose:

[0109] The airflow sound source obtained from the physical quantity or combination of physical quantities in the aerodynamic characteristic quantity is spatially integrated by the finite volume method to obtain the sound source intensity index; and the noise index is then determined based on the sound source intensity index.

[0110] As can be seen from the above embodiments, the aerodynamic characteristic quantities can specifically include multiple physical quantity parameters, such as pressure, velocity, and vorticity, so how to obtain the noise index lgS that is linearly correlated with the noise sound power level SPL based on these aerodynamic characteristic quantities? n , is the problem to be solved by this embodiment. Specifically, based on the airflow sound source that can be obtained from different aerodynamic characteristic physical quantity parameters, the sound source intensity index S is first obtained by spatial integration. n , and then the sound source intensity index S n By performing logarithmic calculation, we can obtain the noise index lgS which is linearly related to the noise sound power level SPL. n .

[0111] Furthermore, this embodiment also provides a possible implementation scheme for obtaining the above-mentioned airflow sound source:

[0112] The airflow sound source is the divergence, absolute value or kinetic energy of a certain physical quantity or combination of physical quantities in the aerodynamic characteristic quantities.

[0113] Specifically, taking the above example where the aerodynamic characteristic quantities include pressure, velocity and vorticity as an example, this embodiment also provides a method for determining the sound source intensity index S n The specific implementation scheme is to determine S by the following sound source intensity index formula n :

[0114] 1. The aerodynamic characteristics used include: vorticity and velocity; the airflow sound source is the divergence of the combination of vorticity and velocity;

[0115] The sound source intensity index S is realized by the following first formula: n Sure:

[0116] Among them, S n Indicates the intensity index of the sound source; is the Hamiltonian operator; the dot represents the dot product between vectors; represents the vorticity vector; represents the velocity vector; dV represents the spatial integral.

[0117] 2. The aerodynamic characteristics used include: vorticity; the airflow sound source is the divergence of vorticity;

[0118] The sound source intensity index S is realized by the following second formula: n Sure:

[0119] 3. The aerodynamic characteristics used include: velocity; the divergence of the velocity of the airflow sound source;

[0120] The sound source intensity index S is realized by the following third formula: n Sure:

[0121] 4. The aerodynamic characteristic quantities used include: pressure; the airflow sound source is the absolute value of pressure;

[0122] The sound source intensity index S is realized by the following fourth formula: n OK: S n =∫|P|dV;

[0123] Wherein, P represents pressure.

[0124] 5. The aerodynamic characteristics used include: velocity; the airflow sound source is the absolute value of the velocity;

[0125] The sound source intensity index S is realized by the following fifth formula: n Sure:

[0126] 6. The aerodynamic characteristics used include: vorticity; the airflow sound source is the absolute value of the vorticity;

[0127] The sound source intensity index S is realized by the following sixth formula: n Sure:

[0128] 7. The aerodynamic characteristics used include: velocity; the kinetic energy of the airflow sound source is velocity;

[0129] The sound source intensity index S is realized by the following seventh formula: n Sure:

[0130] 8. The aerodynamic characteristics used include: vorticity; the airflow sound source is the kinetic energy of the vorticity;

[0131] The sound source intensity index S is realized by the following eighth formula: n Sure:

[0132] Based on this, in the above embodiment, it is necessary to determine the sound source intensity index S according to the aerodynamic characteristic quantity. n When , it can be determined based on any one of the eight formulas provided above, or determined by combining any of them, and this embodiment does not impose any limitation on this. However, it should be noted that in terms of noise prediction accuracy in the entire aerodynamic noise determination process, the first formula has higher accuracy, so in practical applications, the sound source intensity index S implemented by the first formula can be preferably used. n Sure.

[0133] Furthermore, the above also illustrates that the above embodiment does not limit the specific use of one or more of the above eight formulas to calculate the sound source intensity index S. n However, this embodiment also provides another possible implementation scheme based on the accuracy of aerodynamic noise prediction:

[0134] The noise index is determined comprehensively based on all physical quantities in the aerodynamic characteristic quantities.

[0135] That is, if the aerodynamic characteristic quantities include pressure, velocity and vorticity, then in determining the noise index lgS n (Sound source intensity index S n ), all aerodynamic characteristic quantities need to be used for comprehensive determination. Specifically, for example, the first formula with better aerodynamic noise prediction effect in the above embodiment has been selected to determine the sound source intensity index S n At this time, only the two physical quantities of pressure and velocity are used. The physical quantity of pressure in the aerodynamic characteristic quantity is not used. Therefore, the fourth formula above can be combined to assist in calculating the sound source intensity index S n , that is, combining the first and fourth formulas to achieve the sound source intensity index S n Similarly, another combination that is also applicable to this embodiment is: the second formula + the third formula + the fourth formula.

[0136] The purpose of this embodiment is to achieve the sound source intensity index S by making maximum use of all aerodynamic characteristics obtained by steady-state flow field simulation. n Comprehensive calculations are performed to obtain more accurate aerodynamic noise prediction results.

[0137] In the above embodiment, a method for determining aerodynamic noise is described in detail. This application also provides a corresponding embodiment of an aerodynamic noise determination device. It should be noted that this application describes the embodiments of the device from two perspectives: one based on functional modules and the other based on hardware.

[0138] From the perspective of functional modules, as shown in FIG2 , this embodiment provides an aerodynamic noise determination device, including:

[0139] The flow field simulation module 11 is used to establish a flow field calculation domain to simulate the current steady-state flow field of the motor and determine the aerodynamic characteristic quantities of the steady-state flow field;

[0140] An index determination module 12 is used to determine a noise index based on aerodynamic characteristic quantities;

[0141] The noise prediction module 13 is used to substitute the noise index into a pre-established quantitative relationship equation to determine the noise sound power level;

[0142] The establishment of the quantitative relationship equation is achieved by an equation establishment module 20, which includes:

[0143] The parameter simulation unit 21 is used to determine the aerodynamic characteristics of the motor at different speeds, and determine the noise index corresponding to each speed based on each set of aerodynamic characteristics;

[0144] The noise measurement unit 22 is used to measure the noise sound power level of the motor at various speeds;

[0145] The linear analysis unit 23 is used to perform linear correlation analysis on the noise index and the noise sound power level corresponding to each speed according to the least square method to determine the linear relationship equation between the noise index and the noise sound power level as a quantitative relationship equation.

[0146] Since the embodiments of the apparatus part correspond to the embodiments of the method part, please refer to the description of the embodiments of the method part for the embodiments of the apparatus part, and they will not be repeated here.

[0147] The present embodiment provides an aerodynamic noise determination device, which pre-establishes the steady-state flow field of the device under test at different speeds through a parameter simulation unit, and calculates the corresponding aerodynamic characteristic quantity and noise index lgS. n ; Then, the noise measurement unit is used to collect the noise sound power level SPL of the equipment under test under different speed conditions based on the actual test environment; and the linear analysis unit is used to analyze the noise index lgS under different speeds. n The linear relationship between the noise sound power level SPL and the noise sound power level SPL is obtained to obtain a quantitative relationship equation; from then on, when aerodynamic noise prediction is needed in the actual engineering application of the equipment to be tested, the flow field simulation module can obtain the aerodynamic characteristic quantity of the equipment to be tested at this moment through steady-state flow field simulation calculation; when the noise index lgS is determined based on the aerodynamic characteristic quantity through the index determination module n Finally, the quantitative relationship predetermined by the equation establishment module is used to directly obtain the noise sound power level SPL by the noise prediction module.

[0148] The aerodynamic noise prediction achieved by the entire process converts the calculation part of the unsteady flow field into a steady flow field calculation part + a linear correlation calculation part, realizing aerodynamic noise prediction without sound field calculation, which can avoid the inaccurate calculation and large amount of calculation caused by the sound field calculation (unsteady flow field), and is conducive to the rapid prediction of aerodynamic noise to meet the needs of actual engineering. In addition, the quantitative relationship equation determined by this device is obtained based on linear analysis under multiple speed conditions, so it can be adapted to the aerodynamic noise prediction of the equipment under test under different speed conditions. Therefore, when the equipment under test has been modified, optimized or aerodynamic noise prediction is performed at other speeds, there is no need to re-determine the quantitative relationship equation. The aerodynamic noise can be predicted directly based on the steady flow field and the quantitative relationship equation, which can meet the aerodynamic optimization design needs of complex working conditions or external flow fields such as motors.

[0149] The above is a detailed introduction to the aerodynamic noise determination method and device provided by the present application. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of this application.

[0150] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. A method for determining aerodynamic noise, characterized in that: include: Establishing a flow field calculation domain to simulate the current steady-state flow field of the motor, and determining aerodynamic characteristic quantities of the steady-state flow field; Determining a noise index according to the aerodynamic characteristic quantity; Substituting the noise index into a pre-established quantitative relationship equation to determine the noise sound power level; Wherein, the establishment of the quantitative relationship equation includes: Determining the aerodynamic characteristic quantities of the motor at different rotational speeds, and determining the noise index corresponding to each rotational speed according to each group of the aerodynamic characteristic quantities; Measuring the noise sound power level of the motor at each speed; A linear correlation analysis is performed on the noise index and the noise sound power level corresponding to each rotation speed according to the least square method to determine a linear relationship equation between the noise index and the noise sound power level as the quantitative relationship equation.

2. The method for determining aerodynamic noise according to claim 1, characterized in that: Determining the noise index according to the aerodynamic characteristic quantity includes: The airflow sound source obtained from the physical quantity or combination of physical quantities in the aerodynamic characteristic quantity is spatially integrated by the finite volume method to obtain a sound source intensity index; and the noise index is then determined according to the sound source intensity index.

3. The method for determining aerodynamic noise according to claim 2, characterized in that: The airflow sound source is the divergence, absolute value or kinetic energy of a certain physical quantity or a combination of physical quantities in the aerodynamic characteristic quantity.

4. The method for determining aerodynamic noise according to claim 3, characterized in that: The aerodynamic characteristic quantities include: vorticity and velocity; the airflow sound source is the divergence of the combination of vorticity and velocity; Correspondingly, determining the noise index according to the aerodynamic characteristic quantity includes: Determine the sound source intensity index of the airflow sound source according to the first formula, and determine the noise index according to the sound source intensity index; Among them, the first formula is: S n Indicates the sound source intensity index; is the Hamiltonian operator; the points represent the dot product between vectors; represents the vorticity vector; represents the velocity vector; dV represents the spatial integral.

5. The method for determining aerodynamic noise according to claim 3, characterized in that: The aerodynamic characteristic quantity includes: vorticity or velocity; the airflow sound source is the divergence of vorticity or velocity; Correspondingly, determining the noise index according to the aerodynamic characteristic quantity includes: Determine the sound source intensity index of the airflow sound source according to the second formula, and determine the noise index according to the sound source intensity index; Wherein, the second formula is: S n Indicates the sound source intensity index; is the Hamiltonian operator; the points represent the dot product between vectors; represents the vorticity vector; dV represents the spatial integral; Alternatively, determining the noise index according to the aerodynamic characteristic quantity includes: Determine the sound source intensity index of the airflow sound source according to the third formula, and determine the noise index according to the sound source intensity index; Wherein, the third formula is: Represents the velocity vector.

6. The method for determining aerodynamic noise according to claim 3, characterized in that: The aerodynamic characteristic quantity includes: vorticity, velocity or pressure; the airflow sound source is the absolute value of vorticity, velocity or pressure; Correspondingly, determining the noise index according to the aerodynamic characteristic quantity includes: Determine the sound source intensity index of the airflow sound source according to the fourth formula, and determine the noise index according to the sound source intensity index; Wherein, the fourth formula is: S n =∫|P|dV; S n represents the sound source intensity index; P represents pressure; dV represents spatial integration; Alternatively, determining the noise index according to the aerodynamic characteristic quantity includes: Determine the sound source intensity index of the airflow sound source according to the fifth formula, and determine the noise index according to the sound source intensity index; Wherein, the fifth formula is: represents the velocity vector; Alternatively, determining the noise index according to the aerodynamic characteristic quantity includes: Determine the sound source intensity index of the airflow sound source according to the sixth formula, and determine the noise index according to the sound source intensity index; Wherein, the sixth formula is: represents the vorticity vector.

7. The method for determining aerodynamic noise according to claim 3, characterized in that: The aerodynamic characteristic quantity includes: vorticity or velocity; the airflow sound source is the kinetic energy of the vorticity or velocity; Correspondingly, determining the noise index according to the aerodynamic characteristic quantity includes: Determine the sound source intensity index of the airflow sound source according to the seventh formula, and determine the noise index according to the sound source intensity index; Wherein, the seventh formula is: S n Indicates the sound source intensity index; represents the velocity vector; dV represents the spatial integral; Alternatively, determining the noise index according to the aerodynamic characteristic quantity includes: Determine the sound source intensity index of the airflow sound source according to the eighth formula, and determine the noise index according to the sound source intensity index; Wherein, the eighth formula is: represents the vorticity vector.

8. The method for determining aerodynamic noise according to any one of claims 2 to 7, characterized in that: Determining the noise index according to the aerodynamic characteristic quantity includes: The noise index is determined comprehensively based on all physical quantities in the aerodynamic characteristic quantities.

9. An aerodynamic noise determination device, characterized in that: include: The flow field simulation module is used to establish the flow field calculation domain to simulate the current steady-state flow field of the motor and Determining aerodynamic characteristic quantities of the steady-state flow field; An index determination module, used to determine a noise index according to the aerodynamic characteristic quantity; A noise prediction module, used for substituting the noise index into a pre-established quantitative relationship equation to determine the noise sound power level; Wherein, the establishment of the quantitative relationship equation is realized by an equation establishment module, and the equation establishment module includes: A parameter simulation unit, used to determine the aerodynamic characteristic quantities of the motor at different speeds, and determine the noise index corresponding to each speed according to each group of the aerodynamic characteristic quantities; A noise measuring unit, used to measure the noise sound power level of the motor at each speed; The linear analysis unit is used to perform a linear correlation analysis on the noise index and the noise sound power level corresponding to each speed according to the least square method, so as to determine a linear relationship equation between the noise index and the noise sound power level as the quantitative relationship equation.

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