Fan vibration noise analysis method based on incoming flow non-uniformity

Abstract

The invention relates to the technical field of automobile vibration simulation, in particular to a fan vibration noise analysis method based on incoming flow nonuniformity, which comprises the following steps: carrying out vibration analysis on a fan, and determining an excitation factor or an excitation source; establishing a dynamic model of the fan based on simulation software; excitation is applied to the kinetic model for analogue simulation, and a resonance point and a high-vibration area are obtained; adjusting parameters in the dynamic model or optimizing component design, and obtaining and implementing an optimal optimization scheme after multiple times of iterative adjustment. According to the method, the detailed dynamic model of the fan is established through simulation software, the influence of the whole vehicle flow field is considered, and the vibration and noise performance of the fan under the actual working condition can be accurately simulated. Through analogue simulation, key factors causing fan vibration and noise can be accurately identified, and a scientific basis is provided for subsequent optimization design.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive vibration simulation, and specifically to a method for analyzing the vibration and noise of a fan based on the non-uniformity of the incoming flow. Background Art

[0002] In modern automotive engineering, as an important part of the cooling system, the performance of the fan directly affects the thermal management efficiency of the engine and the operating reliability of the whole vehicle. However, during operation, the fan is often affected by various excitation factors such as non-uniform incoming flow and rotational speed changes, resulting in vibration and noise. These vibrations and noises not only reduce the riding comfort of passengers but may also damage the fan and its surrounding components, shortening the service life.

[0003] Most traditional methods for analyzing the vibration and noise of fans are based on simplified models or static analysis, ignoring the influence of dynamic factors such as non-uniform incoming flow. Therefore, it is difficult to accurately evaluate the vibration and noise performance of the fan during actual operation. In addition, even if simulation analysis is carried out, the analysis results often deviate significantly from the actual situation due to insufficient model accuracy or unreasonable excitation application methods.

[0004] Existing methods for analyzing the vibration and noise of fans based on non-uniform incoming flow still have some deficiencies. For example, during the establishment of the dynamic model, the interaction between the fan and its surrounding components and the influence of the vehicle flow field on the fan are often ignored, resulting in insufficient model accuracy. In addition, during the simulation process, the excitation application method may also be unreasonable and unable to accurately reflect the dynamic loads received by the fan during actual operation. Therefore, it is necessary to improve and optimize the existing methods to improve the accuracy and reliability of fan vibration and noise analysis. Summary of the Invention

[0005] In view of the technical problems existing in the prior art, the present invention provides a method for analyzing the vibration and noise of a fan based on non-uniform incoming flow to solve the problem that there is a large deviation between the analysis results of the above-mentioned traditional method for analyzing the vibration and noise of a fan and the actual situation.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: A method for analyzing the vibration and noise of a fan based on non-uniform incoming flow includes the following steps:

[0007] Conduct a vibration analysis of the fan to determine the excitation factors or sources;

[0008] Establish a dynamic model of the fan based on simulation software;

[0009] Apply excitation to the dynamic model for simulation to obtain the resonance points and high-vibration regions;

[0010] Adjust the parameters in the kinetic model or optimize the component design, and after multiple iterative adjustments, obtain the best optimization plan and implement it;

[0011] Conduct actual verification on the optimization results.

[0012] Based on the above technical solutions, the present invention can also be improved as follows.

[0013] Further, the kinetic model is a detailed kinetic model of a fan in the vehicle's entire flow field.

[0014] Further, the detailed kinetic model is established using finite element simulation analysis software to establish the detailed kinetic model of the fan.

[0015] Further, the establishment and simulation steps of the detailed kinetic model include:

[0016] Step A: Define the model parameters, and the parameters include the geometric parameters of the fan blades, the fan rotation speed ω, the flow field characteristic parameters, and the material property parameters;

[0017] Step B: Based on the finite element analysis software, according to the geometric parameters and material property parameters defined in Step A, establish a detailed three-dimensional geometric model of the fan blades and their support structures;

[0018] Step C: Perform mesh division on the three-dimensional geometric model established in Step B to obtain a discretized model for finite element analysis;

[0019] Step D: Adopt a transient solution method to solve the unsteady flow field characteristics of the fan in the flow field at different rotation speeds in the CFD software, and obtain the aerodynamic pressure distribution on the fan blade surface;

[0020] When solving the unsteady flow field characteristics, the influence of the flow field non-uniformity δ on the fan performance needs to be considered;

[0021] Step E: Import the aerodynamic pressure on the fan blade surface obtained in Step D into the finite element analysis software. According to Newton's second law, apply the aerodynamic pressure as an excitation force to the fan blade surface for modal analysis to obtain the kinetic model of the fan; when applying the excitation force, the vibration acceleration response at the blade installation points needs to be considered, and the force at the installation points is calculated based on the vibration acceleration response;

[0022] Step F: Verify the fan kinetic model obtained in Step E to ensure that the model can accurately reflect the vibration response characteristics of the fan in the real flow field.

[0023] Further, when applying excitation to the kinetic model for simulation, in combination with the application of excitation according to Newton's second law, select multiple installation points in the kinetic model, and calculate the force at the installation points according to the vibration acceleration response at the installation points.

[0024] Further, before applying the excitation, the transient solution method is used through CFD software to solve the unsteady flow field characteristics of the fan in the vehicle at different rotational speeds; after the calculation converges, the aerodynamic pressure on the fan surface is imported into the finite element analysis software, and the aerodynamic force is loaded onto the fan surface for modal analysis.

[0025] Further, the transient solution method through CFD software includes the following steps:

[0026] Step 1: Through CFD software, establish a detailed geometric model of the fan and its surrounding flow field, and set appropriate boundary conditions and initial conditions;

[0027] Step 2: In the CFD software, use the transient solution method to solve the unsteady flow field characteristics of the fan in the vehicle at different rotational speeds; the transient solution method takes into account the influence of factors such as fan rotational speed change and flow field non-uniformity on the fan aerodynamic performance;

[0028] Step 3: After the calculation converges, export the aerodynamic pressure distribution data on the fan surface from the CFD software; the calculation convergence means that the solution process meets the predetermined accuracy requirements and the flow field characteristics no longer change significantly with time;

[0029] Step 4: Import the exported aerodynamic pressure distribution data into the finite element analysis software, and calculate the aerodynamic force at each point on the fan surface according to these data;

[0030] Further, when adjusting the parameters in the dynamic model or optimizing the component design, the parameters adjusted in the dynamic model include damping or stiffness, and the adjustment of the parameters and component optimization are to reduce noise and vibration.

[0031] Further, in the actual verification of the optimization results, it includes conducting physical tests in a laboratory environment or testing the vehicle under actual road conditions.

[0032] Moreover, the fan vibration and noise analysis method based on the oncoming flow non-uniformity provided by the present invention has at least the following beneficial effects compared with the prior art.

[0033] The present invention establishes a detailed dynamic model of the fan through simulation software and considers the influence of the vehicle's overall flow field, and can accurately simulate the vibration and noise performance of the fan under actual working conditions. Through simulation, the key factors causing the fan vibration and noise can be accurately identified, providing a scientific basis for subsequent optimization design.

[0034] After identifying the key factors, the present invention changes the vibration characteristics of the fan by adjusting the parameters in the dynamic model (such as damping, stiffness, etc.) or optimizing the component design (such as the shape, material, installation method of the fan blade, etc.), so as to avoid the resonance region and effectively reduce vibration and noise. This optimization method is targeted and effective, and can significantly improve the performance of the fan.

[0035] Through multiple iterative adjustments and optimizations, combined with physical tests in the laboratory environment and vehicle tests under actual road conditions, the present invention can find the optimal optimization plan. This iterative adjustment process ensures the accuracy and reliability of the optimization results, enabling the fan to achieve the expected vibration and noise reduction effect during actual operation.

[0036] The implementation of the present invention can significantly improve the vibration and noise control level of the fan product, thereby enhancing the overall performance and competitiveness of the product. At the same time, by reducing vibration and noise, it can improve the comfort and satisfaction of users, bringing a better user experience. This beneficial effect is not only applicable to automotive fans but also to other fan products that require vibration and noise control. Description of the Drawings

[0037] Figure 1 It is a schematic flow chart of the fan vibration and noise analysis method based on the incoming flow non-uniformity of the present invention;

[0038] Figure 2 It is an axial view of the existing fairing;

[0039] Figure 3 It is a side view of the existing fairing;

[0040] Figure 4 It is the interference between the fan rotor blade and the spatially non-uniform flow field. Detailed Embodiments

[0041] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0042] It should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" in the terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrally formed structure. For those of ordinary skill in the art, the specific meanings of such terms in this patent can be understood according to specific circumstances.

[0043] The modern automobile industry is developing rapidly. In addition to meeting traditional driving and safety requirements, its comfort has become an important area of ​​differentiated competition in the automobile industry. This puts forward more stringent requirements for the vibration and noise control of automobiles. Especially in recent years, as new energy vehicles have gradually entered the mainstream consumer market, especially pure electric vehicles, subsystem noise and vibration refer to the in-car noise and vibration exhibited by the linkage work of the electronic fan, compressor, and blower subsystems after the air-conditioning system is turned on. For fuel vehicles, the in-car response caused by the engine can not only mask the noise and vibration of the subsystem, but also the driver and passengers have a high degree of acceptance of the noise and vibration of the engine. In contrast, pure electric vehicles lack shielding excitation sources, and the subsystem exhibits the characteristics of relatively concentrated narrow-band energy when working at a constant speed, which is easy to be perceived by the driver and passengers and the driver and passengers have a low degree of acceptance. Therefore, subsystem noise is becoming more and more prominent in the noise, vibration and harshness (NVH) of pure electric vehicles.

[0044] In order to meet the basic requirements of automobile heat dissipation performance, the cooling fan is usually required to increase the load and speed, but its vibration and wind noise will also increase, and become one of the main sources of automobile aerodynamic noise. The electric drive system of electric vehicles replaces the fuel vehicle engine with high heat dissipation. The electric drive system is very efficient, the heat dissipation is significantly reduced, and the demand for cooling air is greatly reduced. Therefore, the front face of the car no longer needs a large area of ​​​​heat dissipation grille. At the same time, the pursuit of better aerodynamic performance makes the shape of the front cabin of the car more streamlined, and the air intake grille is more compact. In order to reduce the flow resistance in the front cabin, many cars have cancelled the upper grille, and usually only the air intake grille is designed at the bottom of the front bumper for heat dissipation of the drive and air conditioning systems. The opening area of ​​the air intake grille is significantly smaller than that of a fuel vehicle, and only the lower part of the cooling module is facing the windward airflow ( Figure 2 , Figure 3 ) to improve the wind speed uniformity on the radiator and condenser surfaces. Some vehicles use fully sealed deflectors with good sealing effects, but the wind speed uniformity on the windward side of the heat exchanger and fan is still much lower than that of fuel vehicles. This brings extremely strong inherent unsteady flow problems to the fan flow, mainly the unstable load caused by dynamic and static interference, which seriously affects the NVH performance of the cooling fan in the front cooling module.

[0045] The uneven flow velocity at the fan inlet brings about strong unsteady blade aerodynamic force. This unstable aerodynamic phenomenon is often manifested in the form of a decrease in aerodynamic parameters, and this unstable aerodynamic phenomenon is the source of fan vibration noise.

[0046] When the fan rotor blades rotate in a spatial non-uniform flow field, the airflow velocity and direction to which the blades are subjected will continuously change, such as Figure 4As shown, unsteady blade aerodynamic forces are generated on the blades, resulting in unsteady vibration noise. There is no known suitable theoretical method in this field as the main basis for the development of automotive cooling fans.

[0047] For the aerodynamic force excitation loading of traditional fan vibration noise, the blade aerodynamic forces formed on the surface of the isolated fan rotor blades at different rotational speeds are usually calculated using the CFD steady-state calculation method. This method has acceptable calculation accuracy for the cooling fans of fuel vehicles with relatively uniform intake air, but for the cooling fans of electric vehicles with very uneven intake air, this method does not consider the unsteady blade aerodynamic forces and the simulation results are very unsatisfactory.

[0048] In this regard, the fan vibration noise analysis method based on the inlet flow non-uniformity provided by the present invention can solve the above problems.

[0049] As Figure 1 shown, the fan vibration noise analysis method based on the inlet flow non-uniformity designed by the present invention includes the following steps:

[0050] Conduct a vibration analysis on the fan to determine the excitation factors or sources;

[0051] Establish a dynamic model of the fan based on simulation software;

[0052] Apply excitation to the dynamic model for simulation to obtain the resonance points and high vibration regions;

[0053] Adjust the parameters in the dynamic model or optimize the component design, and after multiple iterative adjustments, obtain the best optimization plan and implement it;

[0054] Conduct actual verification on the optimization results.

[0055] Identify the main excitation factors generated during the operation of the fan. These excitation sources may include inlet flow non-uniformity, fan speed changes, the interaction between the fan blades and air, etc.

[0056] As an implementation manner, the dynamic model is a detailed dynamic model of the fan in the vehicle's flow field.

[0057] Specifically, the detailed dynamic model is specifically established using finite element simulation analysis software (such as ANSYS, Abaqus, etc.) to establish the detailed dynamic model of the fan.

[0058] This model considers the interaction of components such as fan blades, motors, and mounting brackets, as well as the influence of the vehicle's flow field on the fan.

[0059] The detailed dynamic model is specifically established by using finite element simulation analysis software (such as ANSYS, Abaqus, etc.) to establish the detailed dynamic model of the fan. This model not only includes the geometric shape and material of the fan blades, but also considers the stiffness and damping characteristics of components such as the motor and mounting brackets. In addition, the model also considers the influence of the vehicle's overall flow field on the fan, such as the shape of the air intake duct and the vehicle speed.

[0060] Specifically, the steps of applying excitation to the dynamic model for simulation are as follows:

[0061] Step A: Define the model parameters. The parameters include the geometric parameters of the fan blades (such as the number of blades N, blade length L, blade width W, blade thickness T, blade installation angle θ, etc.), fan rotation speed ω, flow field characteristic parameters (such as oncoming flow velocity V, flow field non-uniformity δ, etc.), and material property parameters (such as density ρ, elastic modulus E, damping coefficient ζ, etc.);

[0062] Step B: Based on the finite element analysis software, establish a detailed three-dimensional geometric model of the fan blades and their support structures according to the geometric parameters and material property parameters defined in Step A;

[0063] Step C: Perform mesh division on the three-dimensional geometric model established in Step B to obtain a discretized model for finite element analysis; When performing mesh division, the blade shape, thickness, and flow field characteristics need to be considered to ensure that the mesh quality meets the analysis accuracy requirements;

[0064] Step D: Adopt a transient solution method to solve the unsteady flow field characteristics of the fan in the flow field at different rotation speeds in the CFD software to obtain the aerodynamic pressure distribution on the surface of the fan blades; The solution of the unsteady flow field characteristics needs to consider the influence of the flow field non-uniformity δ on the fan performance;

[0065] Step E: Import the aerodynamic pressure on the surface of the fan blades obtained in Step D into the finite element analysis software. According to Newton's second law, load the aerodynamic pressure as the excitation force onto the surface of the fan blades for modal analysis to obtain the dynamic model of the fan; When loading the excitation force, the vibration acceleration response at the blade installation point needs to be considered, and the force at the installation point is calculated based on the vibration acceleration response;

[0066] Step F: Verify the fan dynamic model obtained in Step E to ensure that the model can accurately reflect the vibration response characteristics of the fan in the real flow field.

[0067] The following specific embodiments are also provided:

[0068] When implementing a method for analyzing the vibration and noise of a fan based on the oncoming flow non-uniformity of the present invention, for the content described in Claim 4, the following steps are specifically executed:

[0069] Step 1: Establish a detailed geometric model of the fan and the surrounding flow field. This includes the geometric shapes and dimensions of components such as fan blades, fan housing, intake ducts, etc., as well as the flow field boundaries around the vehicle. At the same time, set appropriate boundary conditions, such as inlet velocity, outlet pressure, etc., and initial conditions, such as the initial velocity and temperature distribution of the flow field.

[0070] Step 2: In the CFD software, use the transient solution method to solve the unsteady flow field characteristics of the fan. In order to simulate the actual operating conditions of the fan in the vehicle, different rotational speed conditions need to be set, and the influence of flow field non-uniformity on the aerodynamic performance of the fan needs to be considered. The transient solution method can capture the change process of the flow field over time, so as to more accurately evaluate the vibration and noise performance of the fan.

[0071] Step 3: After the calculation converges, export the aerodynamic pressure distribution data on the fan surface from the CFD software. The criterion for calculation convergence can be that the fluctuation amplitude of flow field characteristics (such as velocity, pressure, etc.) is less than a predetermined threshold, or the solution process reaches a predetermined number of iterations. The exported aerodynamic pressure distribution data will be used for subsequent aerodynamic force calculation and modal analysis.

[0072] Step 4: Import the exported aerodynamic pressure distribution data into the finite element analysis software. In the finite element analysis software, establish a detailed dynamic model of the fan, including the geometric shapes and material properties of components such as fan blades, support structures, etc. Then, calculate the aerodynamic forces at each point on the fan surface according to the aerodynamic pressure distribution data, and apply these aerodynamic forces as excitation forces to the corresponding positions on the fan surface.

[0073] Step 5: Conduct modal analysis. In the finite element analysis software, conduct modal analysis on the fan dynamic model loaded with aerodynamic forces. Modal analysis can identify the natural frequencies and vibration modes of the fan, as well as evaluate the vibration response of the fan under the action of aerodynamic forces. By comparing the modal analysis results at different rotational speeds, the vibration and noise performance of the fan under different working conditions can be evaluated, providing a basis for subsequent optimization design.

[0074] Furthermore, when applying excitation to the dynamic model for simulation, in combination with the application of excitation based on Newton's second law, select multiple mounting points in the dynamic model, and calculate the forces on the mounting points according to the vibration acceleration responses of the mounting points.

[0075] This force condition reflects the dynamic loads experienced by the fan during actual operation and is an important basis for evaluating the vibration and noise performance of the fan.

[0076] Further, before applying the excitation, the unsteady flow field characteristics of the fan in the vehicle at different rotational speeds are solved by using a transient solution method through CFD software. After the calculation converges, the aerodynamic pressure on the fan surface is imported into the finite element analysis software, and the aerodynamic force is loaded onto the fan surface for modal analysis.

[0077] Before applying the excitation, it is also necessary to solve the unsteady flow field characteristics of the fan in the vehicle through CFD software. The purpose of this step is to obtain the aerodynamic pressure distribution of the fan at different rotational speeds so as to load the aerodynamic force into the dynamic model for modal analysis. By using the transient solution method, the dynamic response of the fan in the complex flow field can be accurately captured, providing reliable data support for subsequent simulation.

[0078] Specifically, it includes the following steps:

[0079] Step 1: Through CFD (Computational Fluid Dynamics) software, establish a detailed geometric model of the fan and its surrounding flow field, and set appropriate boundary conditions and initial conditions;

[0080] Step 2: In the CFD software, adopt the transient solution method to solve the unsteady flow field characteristics of the fan in the vehicle at different rotational speeds; the transient solution method takes into account the influence of factors such as the change in the fan rotational speed and the flow field non-uniformity on the aerodynamic performance of the fan;

[0081] Step 3: After the calculation converges, export the aerodynamic pressure distribution data on the fan surface from the CFD software; the calculation convergence means that the solution process reaches the predetermined accuracy requirement and the flow field characteristics no longer change significantly with time;

[0082] Step 4: Import the exported aerodynamic pressure distribution data into the finite element analysis software, and calculate the aerodynamic force at each point on the fan surface according to these data.

[0083] Embodiment:

[0084] When implementing a method for analyzing the vibration and noise of a fan based on the incoming flow non-uniformity of the present invention, for the content described in claim 4, the following steps are specifically executed:

[0085] Step 1: Establish a detailed geometric model of the fan and its surrounding flow field. This includes the geometric shapes and dimensions of components such as the fan blades, fan housing, and intake duct, as well as the flow field boundaries around the vehicle. At the same time, set appropriate boundary conditions, such as the inlet velocity, outlet pressure, etc., and initial conditions, such as the initial velocity and temperature distribution of the flow field.

[0086] Step 2: In the CFD software, use the transient solution method to solve the unsteady flow field characteristics of the fan. To simulate the actual operating conditions of the fan in the vehicle, different rotational speed conditions need to be set, and the influence of flow field non-uniformity on the aerodynamic performance of the fan needs to be considered. The transient solution method can capture the change process of the flow field over time, so as to more accurately evaluate the vibration and noise performance of the fan.

[0087] Step 3: After the calculation converges, export the aerodynamic pressure distribution data on the fan surface from the CFD software. The convergence criterion for the calculation can be that the fluctuation amplitude of flow field characteristics (such as velocity, pressure, etc.) is less than a predetermined threshold, or the solution process reaches a predetermined number of iterations. The exported aerodynamic pressure distribution data will be used for subsequent aerodynamic force calculation and modal analysis.

[0088] Step 4: Import the exported aerodynamic pressure distribution data into the finite element analysis software. In the finite element analysis software, establish a detailed dynamic model of the fan, including the geometric shapes and material properties of components such as fan blades and support structures. Then, calculate the aerodynamic forces at each point on the fan surface according to the aerodynamic pressure distribution data, and apply these aerodynamic forces as excitation forces to the corresponding positions on the fan surface.

[0089] Step 5: Conduct modal analysis. In the finite element analysis software, conduct modal analysis on the fan dynamic model loaded with aerodynamic forces. Modal analysis can identify the natural frequencies and vibration modes of the fan, as well as evaluate the vibration response of the fan under the action of aerodynamic forces. By comparing the modal analysis results at different rotational speeds, the vibration and noise performance of the fan under different working conditions can be evaluated, and a basis for subsequent optimization design can be provided.

[0090] As an implementation method, when adjusting the parameters in the dynamic model or optimizing the component design, adjusting the parameters in the dynamic model includes damping or stiffness, and the adjustment of the parameters and component optimization is to reduce noise and vibration. Multiple simulations and adjustments are required to find the best optimization plan.

[0091] Specifically, the method first uses simulation software to establish a detailed dynamic model of the fan. This model considers the interaction of components such as fan blades, motors, and mounting brackets, as well as the influence of the vehicle's overall flow field on the fan. Then, apply excitation to the dynamic model for simulation, and calculate to obtain the resonance points and high vibration regions, so as to identify the key factors causing the fan's vibration and noise.

[0092] After identifying the key factors, the method further adjusts the parameters in the dynamic model, such as increasing damping or reducing stiffness, to change the vibration characteristics of the fan, so that it avoids the resonance region, thereby reducing vibration and noise. At the same time, the component design can also be optimized, such as improving the shape, material, or installation method of the fan blades, to further reduce the generation of vibration and noise.

[0093] Finally, through multiple iterations of adjustment and optimization, the best optimization solution is found, and the optimization results are verified practically to ensure that the fan can achieve the expected vibration and noise reduction effects during actual operation.

[0094] As an implementation method, during the practical verification of the optimization results, it includes conducting physical tests in a laboratory environment or testing the vehicle under actual road conditions.

[0095] In the implementation method of practically verifying the analysis results of the vibration and noise of the optimized fan, the principle is mainly based on two test environments: physical tests in a laboratory environment and vehicle tests under actual road conditions.

[0096] In a laboratory environment, physical tests are used to simulate the vibration and noise performance of the fan under actual working conditions. This test environment can precisely control various variables, such as wind speed, temperature, humidity, etc., so as to more accurately evaluate the effect of the optimization solution. By comparing the fan performance before and after optimization, it can be intuitively seen whether the optimization measures effectively reduce vibration and noise.

[0097] Under actual road conditions, vehicle tests provide an environment closer to the real usage scenario. This test can evaluate the performance of the fan in a complex and changeable road environment, including the vibration and noise levels under different speeds, different road conditions, and different climate conditions. Through actual road tests, the effectiveness and reliability of the optimization solution in actual applications can be further verified.

[0098] In summary, the combination of physical tests in a laboratory environment and vehicle tests under actual road conditions constitutes a complete process for practically verifying the optimization results. This verification method not only ensures the accuracy and controllability of the test but also guarantees the effectiveness and reliability of the optimization solution in actual applications.

[0099] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0100] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A fan vibration noise analysis method based on flow non-uniformity, characterized in that: The following steps are involved: Perform vibration analysis on the fan to determine the excitation factor or source; Establish the dynamic model of the fan based on simulation software; Applying excitation to the dynamic model to perform simulation to obtain resonance points and high vibration areas; Adjust parameters in the dynamic model or optimize component design, obtain the best optimization solution after multiple iterations and implement it; The optimization results are actually verified.

2. The fan vibration noise analysis method based on flow non-uniformity according to claim 1 is characterized in that: The dynamic model is a detailed dynamic model of the fan in the flow field of the entire vehicle.

3. The fan vibration noise analysis method based on flow non-uniformity according to claim 2 is characterized in that: The detailed dynamics model uses finite element simulation analysis software to establish the detailed dynamics model of the fan.

4. The fan vibration noise analysis method based on flow non-uniformity according to claim 3 is characterized in that: The detailed dynamic model establishment and simulation steps include: Step A: defining model parameters, wherein the parameters include geometric parameters of fan blades, fan speed ω, flow field characteristic parameters, and material property parameters; Step B: Based on the finite element analysis software, a detailed three-dimensional geometric model of the fan blade and its supporting structure is established according to the geometric parameters and material property parameters defined in step A; Step C: Meshing the three-dimensional geometric model established in step B to obtain a discretized model for finite element analysis; Step D: using a transient solution method to solve the unsteady flow field characteristics of the fan in the flow field at different speeds in the CFD software, and obtaining the aerodynamic pressure distribution on the fan blade surface; The solution of the unsteady flow field characteristics needs to consider the influence of the flow field non-uniformity δ on the fan performance; Step E: Importing the aerodynamic pressure on the fan blade surface obtained in step D into the finite element analysis software, and according to Newton's second law, loading the aerodynamic pressure as an excitation force onto the fan blade surface for modal analysis to obtain a dynamic model of the fan; the loading of the excitation force needs to take into account the vibration acceleration response of the blade mounting point, and the force on the mounting point is calculated according to the vibration acceleration response; Step F: Verify the fan dynamics model obtained in step E to ensure that the model can accurately reflect the vibration response characteristics of the fan in the real flow field.

5. The fan vibration noise analysis method based on flow non-uniformity according to claim 2, characterized in that: When applying excitation to the dynamic model for simulation, the excitation is applied in combination with Newton's second law, multiple installation points are selected in the dynamic model, and the forces on the installation points are calculated according to the vibration acceleration responses of the installation points.

6. The fan vibration noise analysis method based on flow non-uniformity according to claim 5 is characterized in that: Before applying the excitation, the CFD software is used to solve the unsteady flow field characteristics of the fan in the car at different speeds using a transient solution method; after the calculation converges, the aerodynamic pressure on the fan surface is imported into the finite element analysis software, and the aerodynamic force is loaded onto the fan surface for modal analysis.

7. The fan vibration noise analysis method based on flow non-uniformity according to claim 6 is characterized in that: Using CFD software, the transient solution method includes the following steps: Step 1: Use CFD software to build a detailed geometric model of the fan and its surrounding flow field, and set appropriate boundary conditions and initial conditions; Step 2: In the CFD software, a transient solution method is used to solve the unsteady flow field characteristics of the fan in the car at different speeds; the transient solution method takes into account the influence of factors such as fan speed change and flow field non-uniformity on the aerodynamic performance of the fan; Step 3: After the calculation converges, the aerodynamic pressure distribution data on the fan surface is exported from the CFD software; the calculation convergence means that the solution process reaches the predetermined accuracy requirement and the flow field characteristics no longer change significantly over time; Step 4: Import the exported aerodynamic pressure distribution data into the finite element analysis software, and calculate the aerodynamic force at each point on the fan surface based on these data.

8. The fan vibration noise analysis method based on flow non-uniformity according to claim 1, characterized in that: When adjusting the parameters in the dynamic model or optimizing the component design, the parameters in the dynamic model include damping or stiffness, and the parameters and component optimization are adjusted to reduce noise and vibration.

9. The fan vibration noise analysis method based on flow non-uniformity according to claim 1, characterized in that: Practical validation of the optimization results involves physical experiments in a laboratory environment or testing the vehicle under actual road conditions.

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