Design method for noise-reduction expanded resonator of power battery air cooling system

Abstract

The invention relates to the technical field of automobile part design, in particular to a design method of a noise reduction expansion type resonator of a power battery air cooling system. Comprising the steps of determining a target silencing frequency of a resonator; designing a resonator cavity structure based on the boundary of the automobile trunk; determining the mounting position and the mounting size of a resonator air inlet pipe and the initial mounting size of a resonator air outlet pipe based on the position and the size of an air outlet of the air blower; based on the installation position and size of the resonator air inlet pipe and according to the target silencing frequency of the resonator, simulation analysis is carried out to obtain the installation position of the resonator air outlet pipe; and determining the final mounting size of the resonator air outlet pipe based on simulation analysis. According to the design method for the noise-reduction expanded resonator of the power battery air cooling system, an appropriate resonator structure can be designed in a narrow space, the arrangement space can be fully utilized, the noise elimination amount is increased, the effective noise elimination frequency is expanded under the condition that a real object is not manufactured, and then the high-speed airflow noise of an air blower is improved to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile component design, and in particular to a design method for a noise-reducing expanded resonator of a power battery air cooling system. Background Art

[0002] The power battery cooling system of hybrid vehicles uses forced air cooling in some models, which requires a blower to provide power to force the gas to flow. However, when the blower is running at high speed, it will produce excessive airflow noise, which directly affects the comfort and riding experience of the whole vehicle. In the prior art, there are various ways to reduce the noise of the blower, such as optimizing the structure of the blower to reduce the noise, but the effect is often not obvious, and it is difficult to balance power and reliability. Although the method of installing a muffler at the blower outlet increases a certain cost, it can reduce the noise to a certain extent and achieve customer satisfaction.

[0003] Since the muffler is arranged on the side of the trunk, its space is limited and is even more restricted by the requirements of the convenience of disassembly and assembly. It is necessary to design a muffler with a simple structure, easy disassembly and assembly, and good noise reduction performance. The side-branch resonator used in the acoustic optimization of the traditional automobile intake system pipe is limited by its shape and cannot match the demanding layout space well. In addition, the noise reduction effect is not ideal, so it is abandoned. It is necessary to consider a new resonator design scheme. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the above-mentioned background technology and provide a design method for a noise-reducing expanded resonator for a power battery air cooling system.

[0005] The technical solution of the present invention is: a design method for a noise reduction expansion resonator for a power battery air cooling system, comprising:

[0006] Determine the target sound attenuation frequency and target sound attenuation amount of the resonator;

[0007] Design the resonator cavity structure based on the car trunk boundary;

[0008] Determine the installation position and installation size of the resonator air inlet pipe and the initial installation size of the resonator air outlet pipe based on the position and size of the blower air outlet;

[0009] Based on the installation position and size of the resonator intake pipe and the target noise reduction frequency of the resonator, a simulation analysis is performed to obtain the installation position of the resonator outlet pipe;

[0010] The final installation dimensions of the resonator outlet pipe are determined based on simulation analysis.

[0011] According to a method for designing an expanded resonator for noise reduction in a power battery air cooling system provided in the present application, the method for determining the target silencer frequency of the resonator includes: the target silencer frequency of the resonator is the peak frequency at the rated speed of the blower; the target silencer amount is the difference between the blower outlet noise and the allowable noise.

[0012] According to a method for designing an expanded resonator for noise reduction in a power battery air-cooling system provided in the present application, the method for designing a resonator cavity structure based on the boundary of a car trunk includes: arranging the resonator in a guard plate at the rear left side of the car trunk on the Y side, and constructing the resonator in such a way that the spacing between the resonator and the surrounding components in the guard plate is not less than a set distance and the resonator fills the space in the guard plate to the maximal extent.

[0013] According to a method for designing a noise-reducing expandable resonator for a power battery air-cooling system provided in the present application, the method for determining the installation position and size of the resonator air inlet pipe based on the position and size of the blower air outlet includes: arranging the resonator air inlet pipe on the side of the resonator facing the blower air outlet, designing the direction of the resonator air inlet pipe opening so that the airflow direction points to the center of the resonator cavity, and at the same time making the connecting pipe between the resonator air inlet pipe and the blower air outlet as short as possible and with the least elbows; determining the size of the resonator air inlet pipe in such a way that the flow cross-sectional area of ​​the resonator air inlet pipe is equal to the flow cross-sectional area of ​​the blower air outlet.

[0014] According to a method for designing a noise-reducing expanded resonator for a power battery air-cooling system provided in the present application, the method for determining the initial installation dimensions of the resonator outlet pipe based on the position and dimensions of the blower outlet includes: obtaining the initial installation dimensions of the resonator outlet pipe in accordance with the requirement that the flow cross-sectional area of ​​the resonator outlet pipe is not greater than the flow cross-sectional area of ​​the blower outlet.

[0015] According to a method for designing an expanded resonator for noise reduction in a power battery air cooling system provided in the present application, the method for obtaining the installation position of a resonator outlet pipe based on the installation position of the resonator inlet pipe and performing simulation analysis according to the target noise reduction frequency of the resonator includes: selecting the other sides of the resonator except the installation side and the opposite side of the resonator inlet pipe as the installation side of the resonator outlet pipe; the angle between the outlet direction of the resonator outlet pipe and the inlet direction of the resonator inlet pipe is within a set angle range.

[0016] According to a method for designing a noise-reducing expandable resonator for a power battery air-cooling system provided in the present application, an installation range is delineated on the installation side of the resonator outlet pipe based on the requirements for the arrangement of the resonator outlet pipe, an initial installation position is selected from the installation range to construct a three-dimensional acoustic simulation model of the resonator, the resonator volume, the length of the connecting throat and the cross-sectional area of ​​the connecting throat are identified based on the three-dimensional acoustic simulation model of the resonator, the resonant frequency at the current installation position is calculated based on the resonator resonant frequency calculation formula, and the process is repeated in sequence until the resonant frequencies at all installation positions within the installation range are obtained, and the installation position corresponding to the resonant frequency with the best effect is selected as the installation position of the resonator outlet pipe.

[0017] According to a method for designing an expanded resonator for noise reduction in a power battery air cooling system provided in the present application, the method for selecting an installation position corresponding to a resonant frequency with an optimal effect as the installation position of an air outlet pipe of the resonator includes: selecting an installation position whose resonant frequency is closest to a target silencer frequency as the installation position of the air outlet pipe of the resonator.

[0018] According to a method for designing a noise-reducing expandable resonator for a power battery air-cooling system provided in the present application, the method for determining the final installation size of the resonator outlet pipe based on simulation analysis includes: determining the flow cross-sectional area range of the resonator outlet pipe based on the initial installation size of the resonator outlet pipe; selecting the maximum value in the flow cross-sectional area range of the resonator outlet pipe as the initial value, constructing a resonator data model to perform CFD simulation analysis and verification on the initial value, and verifying whether the resonator meets the design flow resistance target when the flow cross-sectional area of ​​the resonator outlet pipe is the initial value; if the design flow resistance target is met, then reducing a set amplitude on the basis of the initial value for a second CFD simulation analysis and verification, and performing the verification in sequence until a first non-standard value that does not meet the design flow resistance target is obtained for the first time, and selecting a verification value previous to the first non-standard value as the optimal value of the flow cross-sectional area of ​​the resonator outlet pipe.

[0019] According to a method for designing a noise-reducing expandable resonator for a power battery air-cooling system provided in the present application, the resonator outlet pipe is designed to be circular, and a first diameter corresponding to the maximum value in the flow cross-sectional area range of the resonator outlet pipe is used as an initial verification value. A resonator data model is constructed to perform CFD simulation analysis and verification on the initial verification value to verify whether the resonator meets the design flow resistance target when the flow cross-sectional area of ​​the resonator outlet pipe is the initial verification value. If the design flow resistance target is met, a set diameter is reduced on the basis of the first diameter to perform a second CFD simulation analysis and verification, and this is performed in sequence until a first non-standard value that does not meet the design flow resistance target is obtained for the first time, and a verification value previous to the first non-standard value is selected as the optimal value of the flow cross-sectional area of ​​the resonator outlet pipe.

[0020] The advantages of this application are as follows: 1. This application provides a design method for a resonator used for noise reduction of a blower in a power battery air cooling system. The design method of this application can design a suitable resonator structure based on the structure of the car trunk and the blower structure, and can obtain an optimized resonator structure without manufacturing a physical object, ensuring that the formed resonator can meet the requirements of noise reduction of the blower in the air cooling system to the greatest extent, and can make full use of the demanding layout space, with free shape and great design flexibility. By designing the direction of the resonator air inlet port, the airflow direction points to the center of the resonator cavity, making full use of the airflow compression harmonic effect, strengthening the resonant capacity of the resonator, increasing the sound reduction and expanding the effective sound reduction frequency range, thereby maximizing the improvement of the high-speed airflow noise of the blower;

[0021] 2. The method for obtaining the target noise reduction frequency of the resonator in this application is very simple. In fact, the target noise reduction frequency of the resonator obtained in this application is determined by the peak frequency at the rated speed of the blower. In this way, the design goal can be clearly defined at the early stage of design, and the resonator structure that reduces the noise of the blower to the greatest extent can be obtained;

[0022] 3. The present application utilizes the space of the rear guard plate on the left side of the trunk as the installation space of the resonator. In order to maximize the use of the guard plate space, the present application designs the resonator to operate in a manner that fills the guard plate space to the maximum extent. The larger the volume of the resonator, the better the noise reduction effect. At the same time, in order to prevent the resonator from causing interference vibration to the surrounding parts, the present application maintains a certain spacing arrangement between the resonator and the surrounding parts at the beginning of the design, thereby avoiding the occurrence of interference between parts during the use of the vehicle;

[0023] 4. The method for determining the installation position and installation size of the resonator air inlet pipe in the present application is very simple. The installation size of the resonator air inlet pipe is directly determined by the size of the blower air outlet. The flow cross-sectional area of ​​the resonator air inlet pipe is equal to the flow cross-sectional area of ​​the blower air outlet pipe, which can minimize gas attenuation, make the gas flow smoother, and avoid noise. The resonator air inlet pipe is arranged on the side of the resonator facing the blower air outlet. The connecting pipe between the two is the shortest and has the least elbows, which has less gas obstruction, makes the gas flow smoother, and further reduces noise.

[0024] 5. The method for determining the initial installation size of the resonator outlet pipe in the present application is very simple. As long as the initial installation size of the resonator outlet pipe is designed to be no larger than the flow cross-sectional area of ​​the blower outlet, a suitable range, i.e., the initial installation size, is first determined. Subsequently, the initial installation size is simulated and analyzed, which greatly reduces the data processing amount of the simulation analysis and improves the design efficiency.

[0025] 6. The present application designs the installation position of the resonator outlet pipe to be on the side other than the installation side and the opposite side of the resonator inlet pipe. The purpose of such design is to make the inlet and outlet of the resonator intersect, so that the inlet can impact the air in the cavity of the resonator to the greatest extent, strengthen the resonance effect, and maximize the sound reduction of each frequency band of the resonator;

[0026] 7. This application can select the optimal installation position from the installation side that meets the installation position requirements of the resonator outlet pipe by performing three-dimensional acoustic simulation on the resonator, ensuring that the set noise reduction requirements can be achieved to the greatest extent;

[0027] 8. This application can determine whether the current installation position of the resonator outlet pipe can meet the set noise reduction requirements by comparing the resonant frequency obtained by acoustic simulation with the target noise reduction frequency. The overall judgment method is simple.

[0028] 9. This application is to perform CFD simulation analysis on the cross-sectional area of ​​the resonator outlet pipe and obtain the optimal result by iterative calculation. The overall operation is simple, the analysis is fast and efficient, and the cross-sectional area of ​​the resonator outlet pipe that best meets the current requirements can be quickly obtained.

[0029] 10. In the simulation analysis process of the flow cross-sectional area of ​​the resonator outlet pipe, in order to facilitate iterative analysis and calculation, the resonator outlet pipe is selected as a circular pipe. The diameter corresponding to the circular pipe is used as the basis for iterative analysis each time, and the corresponding diameter is increased or decreased for analysis. The operation is simple and the amount of analysis and calculation is greatly reduced.

[0030] The method for designing an expanded resonator for noise reduction in a power battery air cooling system of the present application can design a suitable resonator structure in a small space, and can obtain an optimized resonator structure without manufacturing a physical object, making full use of the layout space, utilizing the harmonic effect of air flow compression, enhancing the resonance capacity of the resonator, increasing the sound reduction amount and expanding the effective sound reduction frequency range, thereby maximizing the improvement of the high-speed airflow noise of the blower. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 : Schematic diagram of the arrangement structure of the resonator of the present application in the trunk of a car;

[0032] Figure 2 : Schematic diagram of the connection structure between the resonator and the blower of the present application;

[0033] Figure 3 : Schematic diagram of the internal structure of the resonator of the present application;

[0034] Figure 4 : Schematic diagram of the resonator design process of this application;

[0035] Among them: 1—resonator air inlet; 2—resonator air outlet; 3—first chamber; 4—second chamber; 5—connecting pipe; 6—throat. DETAILED DESCRIPTION

[0036] The embodiments of the present invention are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0037] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0040] The present application relates to a method for designing an expanded resonator for noise reduction in a power battery air cooling system. The purpose is to design an expanded resonator for noise reduction in a power battery air cooling system of an electric vehicle. The expanded resonator is mainly used to reduce the noise of a blower in a power battery air cooling system. The blower is located at the rear left side of the car trunk in the Y direction, and the position is narrow. Accurate calculation and analysis are required to construct a resonator that fully meets the noise reduction design requirements. The present application analyzes the structure and noise reduction targets, determines the structure of the resonator through simulation analysis, and designs a resonator that fully meets the noise reduction requirements of a power battery air cooling system.

[0041] like Figures 1 to 4 As shown, the specific design method of the present application includes the following steps:

[0042] S1, determining the target sound-absorbing frequency and target sound-absorbing amount of the resonator;

[0043] In fact, it is to determine the noise reduction target that the resonator needs to achieve, which is set according to the outlet noise of the corresponding blower;

[0044] S2. Design the resonator cavity structure based on the boundary of the car trunk;

[0045] Because the resonator of the present application is designed according to the installation position of the blower, the resonator is connected to the blower, and the blower is installed at the rear left side of the car trunk in the Y direction, so the resonator of the present application is also installed at this position. When designing the structure of the resonator, it is generally required that the resonator is as large as possible, because the larger the volume of the resonator cavity, the better the noise reduction effect of the resonator. However, the structure of the trunk should also be taken into consideration. The resonator should try to avoid direct contact with the trunk parts to prevent the resonator from causing vibration interference to these parts during use;

[0046] S3, determining the installation position and installation size of the resonator air inlet pipe and the initial installation size of the resonator air outlet pipe based on the position and size of the blower air outlet;

[0047] Resonator intake pipe (corresponding to the Figure 3 The installation position of the resonator air inlet 1 (the resonator air inlet pipe is a pipe structure installed on the resonator air inlet 1) needs to correspond to the position of the blower air outlet to ensure that the noise will not be aggravated due to excessive pressure changes when the gas blown from the blower air outlet enters the resonator air inlet pipe;

[0048] Installation dimensions of the resonator inlet pipe and resonator outlet pipe (corresponding to the attached Figure 3 The resonator outlet 2 in the resonator, the resonator outlet pipe is a pipe structure installed on the resonator outlet 2) The initial installation size is determined according to the size of the blower outlet; if the installation size of the resonator's inlet pipe and outlet pipe is too large, the gas flow rate from the blower outlet into the resonator will be reduced, and the noise reduction effect cannot be achieved; if the installation size of the inlet pipe and outlet pipe is too small, the gas blown out of the blower outlet will increase in flow rate from the large size to the small size, and the pressure change is too large, which will cause infrasonic noise. Therefore, it is necessary to determine a suitable installation size of the inlet pipe and outlet pipe;

[0049] S4, performing simulation analysis based on the installation position and size of the resonator intake pipe and the target noise reduction frequency of the resonator to obtain the installation position of the resonator outlet pipe;

[0050] The installation position of the resonator outlet pipe needs to correspond to the installation position and size of the resonator inlet pipe, and also needs to meet the target noise reduction frequency of the resonator. The installation position of the resonator outlet pipe is obtained by simulation analysis in this application;

[0051] S5. Determine the final installation size of the resonator outlet pipe based on simulation analysis;

[0052] By simulating and analyzing the initial installation dimensions of the resonator outlet pipe, the final installation dimensions of the resonator outlet pipe are finally obtained. At this point, the installation position and size of the resonator, the installation position and installation dimensions of the resonator inlet pipe, and the installation position and installation dimensions of the resonator outlet pipe have been obtained, and the design of the resonator structure is completed.

[0053] Embodiment 1: This embodiment optimizes the above step S1. Specifically, the method for determining the target silencer frequency and target silencer amount of the resonator is as follows: the target silencer frequency of the resonator is the peak frequency at the rated speed of the blower; the target silencer amount is the difference between the blower outlet noise and the allowable noise.

[0054] Embodiment 2: This embodiment optimizes the above step S2. Specifically, the method for designing the resonator cavity structure based on the boundary of the car trunk is as follows: the resonator is arranged in the guard plate at the rear left side of the car trunk Y, because the blower of the power battery air cooling system is installed at the rear left side of the car trunk Y, and the resonator needs to be installed adjacent to the blower. The guard plate at the rear left side of the car trunk Y is the only suitable location for installing the resonator. Therefore, this application needs to arrange the resonator based on the space inside the guard plate at the rear left side of the car trunk Y. The resonator is constructed according to the requirements that the distance between the resonator and the surrounding parts in the guard plate is not less than the set distance (the set distance in this embodiment is 15mm. In actual application, it is not limited to this value and can be other parameters as long as the needs are met) and the resonator fills the space in the guard plate to the maximum extent.

[0055] The structural design of the resonator needs to meet two conditions. First, it should occupy as much space as possible inside the guard plate at the left rear of the car trunk Y. The larger the volume of the resonator (the volume inside the cavity), the better the noise reduction effect of the resonator. Because in order to achieve the best noise reduction effect as much as possible, the resonator needs to be designed to make the most of the space inside the guard plate at the left rear of the car trunk Y. Second, the resonator will vibrate during the noise reduction process. In order to avoid interference with surrounding components, the resonator needs not to be in direct contact with surrounding components. Therefore, the minimum distance between the resonator designed in this embodiment and the surrounding components does not exceed the set distance. The surrounding components here mainly refer to the left side outer panel of the luggage compartment body-in-white, the inner panel of the left rear wheel cover, the middle part of the inner panel of the rear panel, the luggage compartment electrical wiring harness, the sunroof drain pipe, the luggage compartment interior guard plate, etc. Figure 1As shown in the figure (A indicates the resonator), they are actually all the components around the resonator design space, which together constitute the design boundary of the resonator. The above components are designed before the resonator. When designing the resonator, the above components have been designed and the installation position has been fixed. Therefore, based on these components and the space inside the guard plate at the rear left side of the car trunk Y, the structure of the resonator can be constructed.

[0056] Embodiment 3: This embodiment optimizes the above step S3. Specifically, the method for determining the installation position and installation size of the resonator air inlet pipe and the initial installation size of the resonator air outlet pipe based on the position and size of the blower air outlet includes: a connecting pipe 5 is provided between the resonator air inlet pipe and the air outlet of the blower, such as Figure 2 As shown, the connecting pipe 5 connects the resonator air inlet pipe and the air outlet of the blower. After the gas passes through the connecting pipe 5, there is a certain speed attenuation. If the connecting pipe 5 is very long or has many elbows, the gas flow rate will be attenuated more, which is not conducive to the subsequent noise reduction. Based on this consideration, when designing the installation position of the resonator air inlet pipe, it is necessary to ensure that the connecting pipe 5 is as short as possible and has as few elbows as possible. In this embodiment, the resonator air inlet pipe is arranged on the side of the resonator facing the blower air outlet, so that the distance between the resonator air inlet pipe and the blower air outlet can be ensured to be the shortest, and the length of the connecting pipe 5 is also the shortest. At the same time, because the resonator air inlet pipe and the blower air outlet are arranged on the same side, the connecting pipe 5 can directly connect the resonator air inlet pipe and the blower air outlet without multiple elbows, which can achieve the purpose of minimizing elbows.

[0057] In actual operation, the resonator air inlet pipe is arranged on the side of the resonator facing the blower outlet, so that the axis of the resonator air inlet pipe intersects with the axis of the blower outlet. Figure 3 As shown, the resonator includes a first chamber 3 connected to the resonator intake pipe, a second chamber 4 away from the resonator intake pipe (i.e., the resonant cavity), and a throat 6 connecting the first chamber 3 and the second chamber 4. In order for the resonator to achieve a good noise reduction effect, the gas entering the resonator intake pipe needs to impact the second chamber 4 as much as possible. The more gas impacting the second chamber 4, the better the noise reduction effect. In fact, the axis of the resonator intake pipe is designed to be perpendicular to the second chamber 4 and point to the center of the chamber. This ensures that more airflow impacts the second chamber 4 and achieves the best noise reduction effect.

[0058] After comprehensive consideration, the installation position of the resonator intake pipe can be determined.

[0059] Determining the installation size of the resonator intake pipe is actually determining the flow cross-sectional area of ​​the resonator intake pipe. The resonator intake pipe is generally designed as a round pipe. Determining the installation size of the resonator intake pipe is actually determining the diameter of the resonator intake pipe. The flow cross-sectional area of ​​the resonator intake pipe is determined based on the flow cross-sectional area of ​​the blower outlet. In actual application, it is required that when the gas flowing out of the blower outlet enters the resonator intake pipe, the gas flow rate and pressure should change as little as possible. On the one hand, this can avoid the subsequent weakening of the noise reduction effect caused by the reduction in flow rate, and on the other hand, it can also avoid the problem of increased noise caused by the increase in flow rate. The flow cross-sectional areas of the two are designed to be equivalent. After the gas blown out from the blower outlet enters the resonator intake pipe, the flow rate and pressure will basically not change much, and the best noise reduction effect can be achieved.

[0060] Embodiment 4: This embodiment optimizes the method for determining the initial installation size of the resonator outlet pipe in the above-mentioned step S3. Comprehensive considerations are required to determine the initial installation size of the resonator outlet pipe. The gas is blown out from the blower outlet and enters the resonator from the resonator inlet pipe. A pressure drop will occur when the gas flows in the resonator and finally flows out from the resonator outlet pipe. Generally, the gas flowing out of the resonator outlet pipe needs to maintain a certain flow rate. Since the structure inside the resonator blocks the gas, the flow cross-sectional area of ​​the resonator outlet pipe needs to be smaller than the flow cross-sectional area of ​​the blower outlet. Based on this method, the initial installation size of the resonator outlet pipe can be obtained.

[0061] The initial installation size of the resonator outlet pipe obtained in this embodiment is actually a range, that is, a size range from 0 to the flow cross-sectional area of ​​the blower outlet.

[0062] Embodiment 5: This embodiment optimizes the above-mentioned step S4. Specifically, the method for obtaining the installation position of the resonator outlet pipe by simulation analysis based on the installation position and size of the resonator inlet pipe and according to the target sound absorption frequency of the resonator is: select the other sides of the resonator except the installation side and the opposite side of the resonator inlet pipe as the installation side of the resonator outlet pipe. To achieve an optimal noise reduction effect, the resonator outlet pipe and the resonator inlet pipe need to be in a cross state. This requirement excludes the installation side and the opposite side of the resonator inlet pipe. The resonator itself is a hexahedral structure. Therefore, after excluding two side faces, there are still four side faces that can be considered. However, based on the installation position of the resonator, two side faces with smaller areas of the remaining four side faces of the resonator are excluded (there is not enough space to arrange the resonator outlet pipe). Then, there is no installation space on the side of the resonator facing inward. Therefore, there is only the side with installation space. The installation position of the resonator outlet pipe is determined by this exclusion method.

[0063] Then, the installation angle of the resonator air outlet pipe is determined based on the angle requirement between the air outlet direction of the resonator air outlet pipe and the air inlet direction of the resonator air inlet pipe. The angle between the air outlet direction of the resonator air outlet pipe and the air inlet direction of the resonator air inlet pipe is within the set angle range. The set angle range of this embodiment is 90° to 120°. The air inlet direction of the resonator air inlet pipe has been determined. Based on the set angle range and the air inlet direction of the resonator air inlet pipe, the air outlet direction range of the lower resonator air outlet pipe can be determined.

[0064] In order to achieve a good noise reduction effect, the resonator outlet pipe needs to be arranged on the first chamber 3, that is, the installation position of the resonator outlet pipe is on one side of the first chamber 3, which greatly reduces the range of the installation position of the resonator outlet pipe. Based on this requirement, the installation range can be defined on the installation side of the resonator outlet pipe, and an initial installation position is selected from the installation range to construct a three-dimensional acoustic simulation model of the resonator. The resonator volume, the length of the connecting throat and the cross-sectional area of ​​the throat 6 are identified based on the three-dimensional acoustic simulation model of the resonator. The resonant frequency calculation formula is used to calculate the resonant frequency at the current installation position, and this is performed in sequence until the resonant frequencies of all installation positions within the installation range are obtained, and the installation position corresponding to the resonant frequency with the best effect is selected as the installation position of the resonator outlet pipe.

[0065] In fact, it is to perform a three-dimensional acoustic simulation analysis on each installation position within the installation range, and select the installation position corresponding to the resonance frequency with the best effect as the installation position of the resonator outlet pipe. Because this installation range has been screened many times and the installation range is not large, the amount of calculation is small and the optimal installation position can be obtained quickly.

[0066] Three-dimensional acoustic simulation is a key means to identify the structural form of similar side-branch resonators in an expanded resonator. This is because the core principle of forming similar side-branch resonators in an expanded resonator is the deformation effect of the relative positions of the inlet and outlet pipes to the resonator structure. It is necessary to identify the key parameters of the side-branch resonator in the resonator, namely the volume V of the second chamber 4, the length L and the cross-sectional area S of the throat 6. Based on the sound pressure color map after acoustic simulation, the acoustic space representing the volume V of the second chamber 4 and the acoustic space representing the throats S and L can be clearly distinguished.

[0067] Then use the classical resonator resonant frequency calculation formula:

[0068]

[0069] Where: f——resonator resonant frequency;

[0070] V——the volume of the second chamber 4;

[0071] L——length of throat 6;

[0072] S——throat cross-sectional area;

[0073] c——speed of sound;

[0074] To guide the direction of frequency optimization, when the position of the resonator outlet pipe changes, the direction of f change can be determined by combining the formula. Based on this principle, the position of the resonator outlet pipe is adjusted multiple times, and calculations and analyses are performed in sequence within the installation range until a transmission loss curve that meets the target silencing frequency (the resonant frequency obtained by simulation is close to the target silencing frequency) and silencing amount is obtained. At this time, the corresponding installation position is the optimal installation position of the resonator outlet pipe.

[0075] Embodiment 6: This embodiment optimizes the above-mentioned step S5. The specific method for determining the final installation size of the resonator outlet pipe based on simulation analysis is: perform simulation analysis based on the above-mentioned initial installation size of the resonator outlet pipe, take the blower outlet flow cross-sectional area as the peak value, perform iterative analysis and calculation based on this peak value, and finally determine the optimal value of the resonator outlet pipe flow cross-sectional area.

[0076] Specifically, based on the structure of the resonator obtained as described above, a data model of the resonator is constructed in the CFD simulation software, and the values ​​within the range of the resonator outlet pipe flow cross-sectional area are verified by CFD simulation analysis with the blower outlet flow cross-sectional area as the peak value. The optimal value of the resonator outlet pipe flow cross-sectional area is obtained through multiple iterative analyses.

[0077] In fact, it is an iterative analysis between 0 and the flow cross-sectional area of ​​the blower outlet. The optimal value of the flow cross-sectional area of ​​the resonator outlet pipe is a value closer to the flow cross-sectional area of ​​the blower outlet. In order to simplify the iterative analysis operation, this embodiment selects the maximum value in the flow cross-sectional area range of the resonator outlet pipe (actually the flow cross-sectional area of ​​the blower outlet) as the initial value, and constructs a resonator data model to perform CFD simulation analysis and verification on the initial value to verify whether the resonator meets the design flow resistance target when the flow cross-sectional area of ​​the resonator outlet pipe is the initial value. If the design flow resistance target is met, then a set amplitude is reduced on the basis of the initial value to perform a second CFD simulation analysis and verification, and this is performed in sequence until the first non-standard value that does not meet the design flow resistance target (the design flow resistance is specifically) is obtained for the first time, and the previous verification value of the first non-standard value is selected as the optimal value of the flow cross-sectional area of ​​the resonator outlet pipe, and the installation size of the resonator outlet pipe represented by the optimal value is the final installation size of the resonator outlet pipe.

[0078] The blower outlet flow cross-sectional area is used as the initial value for simulation analysis, and then reduced on this basis, and then it is reduced according to the set amplitude for step-by-step iterative analysis. When the result of the CFD simulation analysis fails to reach the design flow resistance target for the first time, it proves that the corresponding blower outlet flow cross-sectional area does not meet the design requirements. In order to obtain the best effect, the previous verification value of the first non-standard value can be selected as the optimal value of the resonator outlet pipe flow cross-sectional area. This verification value is actually the value that just reaches the design flow resistance target. At this time, the corresponding resonator outlet pipe flow cross-sectional area is the optimal solution (of course, in the case of iterative analysis with this set amplitude, different set amplitudes are used for iterative analysis, and the final results are different. Of course, if the selected set amplitude is small enough, the optimal value may be very close, but in this case, the number of iterative analyses is too many and the amount of calculation is too large).

[0079] This embodiment performs simulation analysis based on the flow cross-sectional area and set amplitude of the blower outlet, but the flow cross-sectional area of ​​the blower outlet is an area parameter. It is not easy to reduce the set amplitude in actual operation. Therefore, in order to simplify the calculation, the resonator outlet pipe is designed to be circular in this case, and the first diameter corresponding to the maximum value in the flow cross-sectional area range of the resonator outlet pipe is used as the initial verification value. A resonator data model is constructed to perform CFD simulation analysis and verification on the initial verification value to verify whether the resonator meets the design flow resistance target when the flow cross-sectional area of ​​the resonator outlet pipe is the initial verification value. If the design flow resistance target is met, the set diameter is reduced on the basis of the first diameter to perform a second CFD simulation analysis and verification, and this is performed in sequence until the first non-standard value that does not meet the design flow resistance target is obtained for the first time, and the previous verification value of the first non-standard value is selected as the optimal value of the flow cross-sectional area of ​​the resonator outlet pipe, that is, the final installation size of the resonator outlet pipe.

[0080] The blower outlet and the resonator outlet pipe are both circular tube structures. The flow cross-sectional area is converted into a diameter for representation, and the increase or decrease of the set amplitude becomes very convenient. In this embodiment, the set amplitude is converted into a set diameter, and the set diameter is 5mm (not limited to this value in actual application). The flow cross-sectional area of ​​the blower outlet is gradually reduced, and each time it is reduced to the set diameter, iterative analysis is performed in sequence to obtain the optimal value of the flow cross-sectional area of ​​the resonator outlet pipe. The overall operation is very simple, the calculation efficiency is high, and the calculation difficulty is reduced.

[0081] According to the above description, it is equivalent to having obtained the structure of the resonator and the installation position and installation dimensions of the resonator's air inlet pipe and air outlet pipe, thus completing the design of the resonator.

[0082] In actual operation, Figure 4As shown, the target silencing frequency of the resonator is determined to be the peak frequency at the rated speed of the blower; the resonator is arranged in the guard plate at the rear left side of the car trunk Y, and the resonator is constructed according to the requirements that the distance between the resonator and the surrounding parts in the guard plate is not less than the set distance and the resonator fills the space in the guard plate to the maximum extent, so as to obtain the design structure of the resonator; the installation size of the resonator intake pipe is obtained according to the requirement that the flow cross-sectional area of ​​the resonator intake pipe is equal to the flow cross-sectional area of ​​the blower outlet, and the resonator intake pipe is arranged on the side of the resonator facing the blower outlet, so that the axis of the resonator intake pipe and the axis of the blower outlet are intersected, thereby determining The installation position of the resonator air inlet pipe; the initial installation size of the resonator air outlet pipe is obtained according to the requirement that the flow cross-sectional area of ​​the resonator air outlet pipe is not greater than the flow cross-sectional area of ​​the blower outlet; the other sides of the resonator except the resonator air inlet pipe installation side and the opposite side are selected as the resonator air outlet pipe installation side, and then the installation angle of the resonator air outlet pipe is determined based on the angle requirement between the air outlet direction of the resonator air outlet pipe and the air inlet direction of the resonator air inlet pipe, the installation range is delineated on the resonator air outlet pipe installation side, an initial installation position is selected from the installation range to construct a three-dimensional acoustic simulation model of the resonator, and the resonator is identified based on the three-dimensional acoustic simulation model of the resonator. The resonator volume, the length of the connecting throat and the cross-sectional area of ​​the connecting throat are used to calculate the resonant frequency at the current installation position based on the resonant frequency calculation formula, and the resonant frequencies at all installation positions within the installation range are calculated in sequence, and the installation position corresponding to the resonant frequency with the best effect is selected as the installation position of the resonator outlet pipe; the resonator outlet pipe flow cross-sectional area range is obtained based on the initial installation size of the resonator outlet pipe, that is, 0 to the blower outlet flow cross-sectional area, and the diameter corresponding to the blower outlet flow cross-sectional area is used as the first diameter corresponding to the maximum value in the resonator outlet pipe flow cross-sectional area range, and the first diameter is used as the initial verification value. Construct a resonator data model to perform CFD simulation analysis and verification on the initial verification value to verify whether the resonator meets the design flow resistance target when the flow cross-sectional area of ​​the resonator outlet pipe is the initial verification value. If the design flow resistance target is met, reduce a set diameter on the basis of the first diameter to perform a second CFD simulation analysis and verification, and perform this process in sequence until the first non-standard value that does not meet the design flow resistance target is obtained for the first time. Select the previous verification value of the first non-standard value as the optimal value of the flow cross-sectional area of ​​the resonator outlet pipe, and the installation size of the resonator outlet pipe represented by the optimal value is the final installation size of the resonator outlet pipe. At this point, the design of the resonator is completed.

[0083] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A design method for a noise reduction expansion resonator for a power battery air cooling system, characterized in that: include: Determine the target sound attenuation frequency and target sound attenuation amount of the resonator; Design the resonator cavity structure based on the car trunk boundary; Determine the installation position and installation size of the resonator air inlet pipe and the initial installation size of the resonator air outlet pipe based on the position and size of the blower air outlet; Based on the installation position and size of the resonator intake pipe and the target noise reduction frequency of the resonator, a simulation analysis is performed to obtain the installation position of the resonator outlet pipe; The final installation dimensions of the resonator outlet pipe are determined based on simulation analysis.

2. A method for designing a noise reduction expansion resonator for a power battery air cooling system according to claim 1, characterized in that: The method for determining the target noise reduction frequency of the resonator includes: the target noise reduction frequency of the resonator is the peak frequency at the rated speed of the blower; the target noise reduction amount is the difference between the blower outlet noise and the allowable noise.

3. A method for designing a noise reduction expansion resonator for a power battery air cooling system according to claim 1, characterized in that: The method for designing a resonator cavity structure based on the boundary of a car trunk includes: arranging the resonator in a guard plate at the rear left side of the car trunk Y, and constructing the resonator in accordance with the requirements that the distance between the resonator and the surrounding parts in the guard plate is not less than a set distance and the resonator fills the space in the guard plate to the maximum extent.

4. A method for designing a noise reduction expansion resonator for a power battery air cooling system according to claim 1, characterized in that: The method for determining the installation position and installation size of the resonator air inlet pipe based on the position and size of the blower air outlet includes: arranging the resonator air inlet pipe on the side of the resonator facing the blower air outlet, designing the direction of the resonator air inlet pipe opening so that the air flow direction points to the center of the resonator cavity, and at the same time making the connecting pipe between the resonator air inlet pipe and the blower air outlet as short as possible and with the least elbows; determining the size of the resonator air inlet pipe in such a way that the flow cross-sectional area of ​​the resonator air inlet pipe is equal to the flow cross-sectional area of ​​the blower air outlet.

5. A method for designing a noise reduction expansion resonator for a power battery air cooling system according to claim 1 or 4, characterized in that: The method for determining the initial installation size of the resonator air outlet pipe based on the position and size of the blower air outlet includes: obtaining the initial installation size of the resonator air outlet pipe according to the requirement that the flow cross-sectional area of ​​the resonator air outlet pipe is not greater than the flow cross-sectional area of ​​the blower air outlet.

6. A method for designing a noise reduction expansion resonator for a power battery air cooling system according to claim 1, characterized in that: The method for obtaining the installation position of the resonator outlet pipe by performing simulation analysis based on the installation position of the resonator inlet pipe and according to the target sound absorption frequency of the resonator includes: selecting the other sides of the resonator except the installation side and the opposite side of the resonator inlet pipe as the installation side of the resonator outlet pipe; the angle between the outlet direction of the resonator outlet pipe and the inlet direction of the resonator inlet pipe is within a set angle range.

7. A method for designing a noise reduction expansion resonator for a power battery air cooling system according to claim 6, characterized in that: Based on the requirements for the arrangement of the resonator outlet pipe, an installation range is defined on the installation side of the resonator outlet pipe, and an initial installation position is selected from the installation range to construct a three-dimensional acoustic simulation model of the resonator. The volume of the resonator, the length of the connecting throat and the cross-sectional area of ​​the connecting throat are identified based on the three-dimensional acoustic simulation model of the resonator. The resonant frequency calculation formula is used to calculate the resonant frequency at the current installation position, and this process is performed in sequence until the resonant frequencies at all installation positions within the installation range are obtained. The installation position corresponding to the resonant frequency with the best effect is selected as the installation position of the resonator outlet pipe.

8. A method for designing a noise reduction expansion resonator for a power battery air cooling system as claimed in claim 7, characterized in that: The method of selecting the installation position corresponding to the resonance frequency with the best effect as the installation position of the resonator outlet pipe includes: selecting the installation position whose resonance frequency is closest to the target sound elimination frequency as the installation position of the resonator outlet pipe.

9. A method for designing a noise reduction expansion resonator for a power battery air cooling system as claimed in claim 5, characterized in that: The method for determining the final installation size of the resonator outlet pipe based on simulation analysis includes: determining the flow cross-sectional area range of the resonator outlet pipe based on the initial installation size of the resonator outlet pipe; selecting the maximum value in the flow cross-sectional area range of the resonator outlet pipe as the initial value, constructing a resonator data model to perform CFD simulation analysis and verification on the initial value, and verifying whether the resonator meets the design flow resistance target when the flow cross-sectional area of ​​the resonator outlet pipe is the initial value; if the design flow resistance target is met, reducing a set amplitude on the basis of the initial value to perform a second CFD simulation analysis and verification, and performing the verification in sequence until a first non-standard value that does not meet the design flow resistance target is obtained for the first time, and selecting a verification value before the first non-standard value as the optimal value of the flow cross-sectional area of ​​the resonator outlet pipe.

10. A method for designing a noise reduction expansion resonator for a power battery air cooling system according to claim 9, characterized in that: The resonator outlet pipe is designed to be circular, and the first diameter corresponding to the maximum value in the flow cross-sectional area range of the resonator outlet pipe is taken as the initial verification value. The resonator data model is constructed to perform CFD simulation analysis and verification on the initial verification value to verify whether the resonator meets the design flow resistance target when the flow cross-sectional area of ​​the resonator outlet pipe is the initial verification value. If the design flow resistance target is met, a set diameter is reduced on the basis of the first diameter to perform a second CFD simulation analysis and verification, and this is performed in sequence until the first non-standard value that does not meet the design flow resistance target is obtained for the first time, and the previous verification value of the first non-standard value is selected as the optimal value of the flow cross-sectional area of ​​the resonator outlet pipe.

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