Acoustic test simulation device and wind tunnel duct

Abstract

The application discloses an acoustic test simulation device and a wind channel pipe, which comprise a wind source assembly and a wind channel assembly. The wind source assembly is provided with a air supply port, and the wind channel assembly is connected to the air supply port of the wind source assembly. The wind channel assembly is provided with the wind channel pipe, which is provided with an air inlet, an air outlet and a flow uniformizing section between the air inlet and the air outlet. The upper edges of the air inlet and the air outlet are flush, and the lower edge of the air outlet is lower than the lower edge of the air inlet, so that the top inner wall of the flow uniformizing section is flush, and the bottom inner wall of the flow uniformizing section is inclined from the air inlet to the air outlet. The application can obtain outflow with uniform and stable wind speed distribution and expand the air outlet area in limited axial length space, and meets the test requirements of portable electronic products in a wind noise environment.

Description

Technical Field

[0001] This invention relates to the field of acoustic testing technology, and in particular to an acoustic testing simulation device and a duct. Background Technology

[0002] With the widespread use of portable electronic products (such as headphones and microphones), their performance in complex outdoor acoustic environments is receiving increasing attention. To ensure the reliability and stability of products in real-world use scenarios, it is necessary to simulate outdoor wind noise environments under laboratory conditions and conduct acoustic tests on electronic products. In existing technologies, fans (such as centrifugal fans) are typically used as air source devices to simulate outdoor wind conditions. However, the outlet airflow distribution of such devices is uneven, making it difficult to create a stable and controllable wind field environment. This results in a significant deviation between the test conditions and actual outdoor wind conditions, severely affecting the accuracy and reliability of the test results. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes an acoustic testing simulation device and a duct, which can obtain a uniform and stable outflow with wind speed distribution and expand the air outlet area within a limited length space, so as to meet the testing needs of portable electronic products in windy noise environments.

[0004] On one hand, embodiments of the present invention provide an acoustic testing simulation device, comprising: The air source component is equipped with an air outlet; A duct assembly is connected to the air outlet of the air source assembly. The duct assembly is provided with a duct pipe, which is provided with an air inlet, an air outlet, and a flow equalization section located between the air inlet and the air outlet. The upper edges of the air inlet and the air outlet are flush, and the lower edge of the air outlet is lower than the lower edge of the air inlet, so that the top inner wall of the flow equalization section is flush, while the bottom inner wall of the flow equalization section slopes from the air inlet toward the air outlet.

[0005] According to some embodiments of the present invention, the angle of inclination of the bottom inner wall of the air duct from the air inlet toward the air outlet is 2.10°±0.50°.

[0006] According to some embodiments of the present invention, the straight-line distance between the air inlet and the air outlet is 1146±5mm, the height of the air inlet is 250±5mm, and the height of the air outlet is 292±5mm.

[0007] According to some embodiments of the present invention, the air inlet and the air outlet are of equal size.

[0008] According to some embodiments of the present invention, the duct includes a nested inner tube and an outer tube; the inner tube is an integral structure, or the inner tube is a sheet metal fully welded structure.

[0009] According to some embodiments of the present invention, the inner tube and the outer tube are provided with a sealing step recess on the air inlet side.

[0010] According to some embodiments of the present invention, a grid mesh is installed at the connection between the air source assembly and the air duct assembly.

[0011] According to some embodiments of the present invention, a quick-release structure is provided between the air source assembly and the air duct assembly, and a movable guide rail is installed on the bottom or both sides of the air duct assembly.

[0012] According to some embodiments of the present invention, a first sound insulation material is filled inside the air duct assembly and between the inner tube and the outer tube; And / or, the air source assembly is filled with a second sound insulation material.

[0013] On the other hand, embodiments of the present invention provide a duct pipe, the duct pipe being provided with an air inlet, an air outlet, and a flow equalization section located between the air inlet and the air outlet. The upper edges of the air inlet and the air outlet are flush, and the lower edge of the air outlet is lower than the lower edge of the air inlet, so that the top inner wall of the flow equalization section is flush, while the bottom inner wall of the flow equalization section is inclined from the air inlet toward the air outlet.

[0014] The embodiments of the present invention have at least the following beneficial effects: An air duct assembly is added to the air outlet of the air source component, and the structure of the air duct is optimized so that the top inner wall of the air duct is flat, while the bottom inner wall slopes from the air inlet to the air outlet, forming an asymmetrical flow channel structure. This causes the flow cross-sectional area of ​​the air duct to gradually increase along the airflow direction. The guiding effect of the bottom sloped wall guides the airflow to expand along the wall, which, together with the axial constraint of the top flat wall, eliminates the difference in air velocity in the vertical direction of the air outlet cross-section. As a result, a uniform and stable airflow distribution is obtained within a limited length space, and the air outlet area is expanded, meeting the testing requirements of portable electronic products in windy and noisy environments.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1This is a schematic diagram of the acoustic testing simulation device according to an embodiment of the present invention; Figure 2 for Figure 1 A schematic cross-sectional view of the acoustic testing simulation device is shown. Figure 3 This is a cross-sectional view of the air duct structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the distribution of measurement points and measurement data of a centrifugal fan according to an embodiment of the present invention; Figure 5 This is a schematic diagram showing the distribution of measurement points for multiple design schemes in an embodiment of the present invention. Figure 6 This is a schematic diagram of the structure of design A in embodiment A of the present invention; Figure 7 This is a schematic diagram of the structure of Design B in an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of design C according to an embodiment of the present invention; Figure 9 This is a schematic diagram of design D in an embodiment of the present invention.

[0017] Figure label: Air source assembly 100, air outlet 101, housing 110, centrifugal fan 120, outlet 121, airflow inlet 122, volute 123, baffle plate 124, second sound insulation material 130, air duct assembly 200, air duct pipe 210, air inlet 211, air outlet 212, flow equalization section 213, inner pipe 214, outer pipe 215, sealing step recess 216, first sound insulation material 220, grille 230, quick-release structure 240, moving guide rail 250. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0020] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, and "above," "below," "within," etc. are understood to include the stated number. If "first," "second," etc. are used in the description, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0021] In the description of this invention, unless otherwise explicitly defined, terms such as "set," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0022] Fans are general-purpose mechanical equipment widely used in industrial ventilation, dust removal and purification, heat dissipation and cooling, and many other applications. The basic working principle of a fan is that an electric motor drives an impeller to rotate at high speed, converting electrical energy into the kinetic and pressure energy of the gas. This compresses and accelerates the gas, giving it sufficient energy to form a directional airflow. Based on the different airflow patterns, fans can be mainly divided into centrifugal fans, axial fans, and mixed-flow fans. Among them, centrifugal fans are widely used in engineering due to their mature structure, wide pressure range, and strong applicability. When a centrifugal fan is working, the gas enters the impeller and is thrown towards the outer edge of the impeller by the centrifugal force generated by the impeller's rotation. After being collected by the volute, it is discharged from the outlet. However, due to the wake effect generated by the impeller rotation, the geometric asymmetry of the volute, and airflow separation, the original outflow from the centrifugal fan outlet exhibits a significant problem of uneven velocity distribution. This manifests as locally higher and locally lower airflow velocities at the outlet cross-section, resulting in a noticeable non-uniform airflow characteristic.

[0023] In conventional applications of wind turbines, the focus is usually on macroscopic performance indicators such as air volume, total pressure, and noise, while less attention is paid to the uniformity of the outlet airflow velocity distribution. However, in certain specialized applications with high requirements for wind farm quality, the uniformity of the outlet airflow becomes a crucial factor that cannot be ignored. To address the problem of uneven airflow distribution at the centrifugal fan outlet, engineering practice typically employs the following two mainstream methods to achieve flow uniformity: One method is to extend the straight pipe section. This is the simplest and most direct method, which involves connecting a sufficiently long straight pipe section downstream of the fan outlet. Utilizing the turbulent diffusion and momentum exchange of airflow within the pipe, the wind speed profile naturally develops along the flow direction, gradually approaching a uniform distribution in a fully developed state. However, this method typically requires a large straight pipe section, significantly increasing the overall size and footprint of the equipment, making it difficult to implement in space-constrained applications (such as laboratories and compact testing systems). Furthermore, the inlet and outlet of the straight pipe section have the same cross-sectional dimensions, which is not conducive to expanding the outlet area of ​​the testing equipment.

[0024] The second method involves installing internal flow equalization devices. This method involves installing flow equalization elements such as guide vanes, flow straighteners, or perforated plates inside the duct to achieve flow equalization through artificial intervention in the airflow structure. Specifically, guide vanes adjust airflow redistribution by changing the local flow direction and generating local resistance, breaking the jet concentration phenomenon; flow straighteners divide and guide the airflow through a grid structure, suppressing large-scale vortex structures; and perforated plates force the airflow to be evenly distributed across the cross-section through surface resistance constraints. Although these methods can achieve a certain flow equalization effect in a relatively short space, their drawbacks include introducing significant additional pressure drop losses, increasing the energy consumption burden of the fan, and the flow equalization devices themselves may generate new flow disturbances and regenerated noise, bringing new adverse effects to the overall quality of the wind farm.

[0025] In recent years, with the widespread application of portable electronic products (such as Bluetooth headsets, microphones, and hearing aids), their performance in complex outdoor acoustic environments has received increasing attention. To ensure the reliability and stability of products in real-world use scenarios, it is necessary to simulate outdoor wind noise environments under laboratory conditions and conduct systematic acoustic testing and evaluation of electronic products. In existing technologies, fans (especially centrifugal fans) are typically used as wind source devices to simulate outdoor wind conditions. However, as mentioned earlier, the outlet airflow distribution of such fan devices exhibits significant non-uniformity, making it difficult to form a stable, uniform, and controllable wind field environment. This non-uniform inflow condition leads to a large deviation between the test wind field and actual outdoor natural wind conditions, which not only affects the accuracy and repeatability of wind noise test results but may also cause non-representative excitation of the test sample by local high-speed airflow areas, thereby misleading the product's noise reduction optimization direction.

[0026] Therefore, please refer to Figure 1 , Figure 2 and Figure 3This embodiment discloses an acoustic testing simulation device, including a wind source assembly 100 and a duct assembly 200. The wind source assembly 100 is provided with an air outlet 101, and the duct assembly 200 is connected to the air outlet 101 of the wind source assembly 100. The duct assembly 200 is provided with a duct pipe 210, which is provided with an air inlet 211, an air outlet 212, and a flow equalization section 213 located between the air inlet 211 and the air outlet 212. The upper edges of the air inlet 211 and the air outlet 212 are flush, and the lower edge of the air outlet 212 is lower than the lower edge of the air inlet 211, so that the top inner wall of the flow equalization section 213 is flush, while the bottom inner wall of the flow equalization section 213 is inclined from the air inlet 211 toward the air outlet 212.

[0027] The air source assembly 100 includes a housing 110 and a centrifugal fan 120 installed inside the housing 110. An air outlet 101 is located on the housing 110 and communicates with the outlet 121 of the centrifugal fan 120, which serves as the airflow power source. The flow equalization section 213 of the duct 210 serves as a region for airflow straightening and flow field homogenization. The first end of the flow equalization section 213 is an air inlet 211, and the second end is an air outlet 212. The inner wall of the flow equalization section 213 is smoothed to minimize frictional disturbance and boundary layer separation of the airflow, thereby ensuring good velocity uniformity of the airflow after passing through the flow equalization section 213.

[0028] For example, in an ideal design, the top inner wall of the duct 210 remains horizontal, while the bottom inner wall gradually slopes downwards from the air inlet 211 towards the air outlet 212, with the slope angle as follows: Figure 2 and Figure 3 As indicated by the mark R, the air duct 210 has a gradually expanding configuration, which makes the height of the air outlet 212 greater than the height of the air inlet 211, effectively increasing the air outlet cross-sectional area and meeting the test requirements for large-area uniform air supply.

[0029] Therefore, an air duct assembly 200 is added to the air outlet 101 of the air source assembly 100, and the structure of the air duct 210 is optimized so that the top inner wall of the air duct 210 is flush, and the bottom inner wall is inclined from the air inlet 211 to the air outlet 212, forming an asymmetrical flow channel structure. This causes the flow cross-sectional area of ​​the air duct 210 to gradually increase along the airflow direction. Through the guiding effect of the inclined bottom wall, the airflow at the bottom is guided to expand along the wall. Combined with the axial constraint of the flush top wall, the difference in wind speed in the vertical direction of the air outlet cross-section is eliminated. Thus, a uniform and stable airflow with a wide airflow distribution is obtained within a limited length space, and the air outlet area is expanded, meeting the testing requirements of portable electronic products in windy and noisy environments.

[0030] In one engineering application example, based on the functional requirements of the actual testing scenario, the following requirements are proposed for the design parameters of the testing equipment for portable electronic products in windy noise environments: Average wind speed requirement: The average wind speed at the outlet section 212 should be controlled within the range of 20±1 MPH (miles per hour) to meet the accuracy requirements of the test conditions for airflow velocity. Wind speed uniformity requirement: The wind speed distribution on the air outlet 212 section should be as uniform as possible to effectively reduce the adverse effects of local wind speed differences on the consistency and reliability of test results; Structural dimension constraints: The total length of the equipment should be controlled within 1700mm; considering the size of the air source component 100, the length of the air duct component 200 should be controlled within 1200mm to adapt to engineering application scenarios with limited space.

[0031] Based on the above design parameters, this embodiment focuses on the key performance indicator of wind speed uniformity at the air outlet 212 section and designs multiple structural schemes for comparative analysis. To ensure the scientific nature and comparability of the comparative analysis, the centrifugal fan 120 built into the air source component 100 remains consistent in each scheme, so that under the same air source conditions, the changes in wind speed distribution caused by structural differences in each scheme can be independently evaluated.

[0032] Please refer to Figure 2 The centrifugal fan 120 has a volute 123 with an outlet 121. A baffle plate 124 (also called a volute tongue) is located at the outlet 121. The baffle plate 124 is an internal structural component of the centrifugal fan 120, and its main functions include regulating the airflow and pressure characteristics of the fan outlet 121, while also providing noise reduction and dust prevention to a certain extent. Due to the obstruction of the baffle plate 124, the height of the airflow inlet 122 of the centrifugal fan 120 is smaller than the height of the outlet 121. The outlet 121 of the centrifugal fan 120 refers to the interface used to connect the centrifugal fan 120 to external structures, while the airflow inlet 122 refers to the location where the internal airflow of the fan flows outward. In this embodiment, the height of the airflow inlet 122 of the centrifugal fan 120 is 149 mm, and the height of the outlet 121 of the centrifugal fan 120 is 250 mm.

[0033] To obtain baseline wind speed distribution data at outlet 121 of centrifugal fan 120, multiple measuring points were arranged at the cross-section of outlet 121 of centrifugal fan 120 to measure the wind speed at each measuring point. Please refer to... Figure 4 And Table 1, Figure 4The left side shows the location distribution of each measuring point at outlet 121 of centrifugal fan 120, and Table 1 shows the wind speed measurement data corresponding to each measuring point. The average wind speed at all test points is 29.15 MPa.

[0034] To intuitively and quantitatively measure the uniformity of wind speed at the vent section 212, this embodiment introduces standard deviation as an evaluation index. Standard deviation is a statistic describing the dispersion of data, reflecting the degree of deviation of the wind speed value at each measurement point from the average value. The smaller the standard deviation, the closer the wind speed value at each measurement point is to the average value, i.e., the more uniform the wind speed distribution; conversely, the larger the standard deviation, the higher the dispersion of the wind speed distribution, and the worse the uniformity.

[0035] Calculations show that, under the baseline test conditions of this embodiment, the standard deviation of the wind speed at each measuring point at the outlet 121 of the centrifugal fan 120 is approximately 3.59. This value will serve as a benchmark reference for subsequent comparative analysis of various structural optimization schemes, used to evaluate the improvement effect of different schemes on wind speed uniformity. Please refer to... Figure 5 Multiple measuring points are arranged at the cross-section of the air outlet 212 of the air duct 210 to measure the wind speed at each measuring point.

[0036] Design A: Please refer to Figure 6 And Table 2, Figure 6 The left side shows a schematic diagram of the structure of the duct 210 of this design, and Table 2 shows the wind speed measurement data at each measuring point of this design. In this design, the top inner wall of the duct 210 slopes upward from the air inlet 211 towards the air outlet 212, and the bottom inner wall of the duct 210 slopes downward from the air inlet 211 towards the air outlet 212; that is, the duct 210 is generally funnel-shaped. This design can enlarge the cross-sectional size of the air outlet 212 to increase the cross-sectional area of ​​the air supply. The straight length of the duct 210 (e.g., ...) is... Figure 6 The height dimension of the air inlet 211 (as indicated by the mark L) is 1016mm; Figure 6 (As shown by the mark H1) is equal to the size of the air outlet 122 of the centrifugal fan 120, which is 149mm; the height of the air outlet 212 (as shown by the mark H1) is equal to the size of the air outlet 122 of the centrifugal fan 120, which is 149mm; Figure 6 The wind speed (marked H2) is 292 mm. The calculated standard deviation of the wind speed measurement data is 4.53, and the average wind speed is approximately 22.33 MPa.

[0037] Design B: Please refer to Figure 7 And Table 3, Figure 7The left side shows a structural schematic diagram of the duct 210 of this design, and Table 3 shows the wind speed measurement data at various measurement points. In this design, the upper edges of the air inlet 211 and air outlet 212 of the duct 210 are flush, and the lower edge of the air outlet 212 is lower than the lower edge of the air inlet 211, so that the top inner wall of the duct 210 is flush, while the bottom inner wall of the duct 210 slopes from the air inlet 211 towards the air outlet 212. This design can increase the cross-sectional size of the air outlet 212 to increase the cross-sectional area of ​​the air supply. The straight length of the duct 210 (e.g., ...) is... Figure 7 The height dimension of the air inlet 211 (as indicated by the mark L) is 1016mm; Figure 7 (As shown by the mark H1) is equal to the size of the air outlet 122 of the centrifugal fan 120, which is 149mm; the height of the air outlet 212 (as shown by the mark H1) is equal to the size of the air outlet 122 of the centrifugal fan 120, which is 149mm; Figure 7 The diameter (as indicated by H2 in the middle) is 292 mm; the angle of downward inclination of the inner wall of the bottom of the duct 210 is approximately 8.01°. The calculated standard deviation of the wind speed measurement data is 4.61, and the average wind speed is approximately 23.06 MPa.

[0038] Design C: Please refer to Figure 8 And Table 4, Figure 8 The left side shows a schematic diagram of the structure of the duct 210 of this design, and Table 4 shows the wind speed measurement data at each measurement point of this design. In this design, the upper edges of the air inlet 211 and air outlet 212 of the duct 210 are flush, and the lower edge of the air outlet 212 is lower than the lower edge of the air inlet 211, so that the top inner wall of the duct 210 is flush, while the bottom inner wall of the duct 210 slopes from the air inlet 211 towards the air outlet 212. This design can increase the cross-sectional size of the air outlet 212 to increase the cross-sectional area of ​​the air supply. The straight length of the duct 210 (e.g., ...) is... Figure 8 The height of the air inlet 211 (as indicated by the mark L) is 1146mm; Figure 8 (As shown by the mark H1) is equal to the size of the air outlet 122 of the centrifugal fan 120, which is 149mm; the height of the air outlet 212 (as shown by the mark H1) is equal to the size of the air outlet 122 of the centrifugal fan 120, which is 149mm; Figure 8 The diameter (as indicated by H2) is 292 mm; the angle of downward inclination of the inner wall of the bottom of the duct 210 is approximately 7.11°. The calculated standard deviation of the wind speed measurement data is 3.48, and the average wind speed is approximately 15.78 MPa.

[0039] Design D: Please refer to Figure 9 And Table 5, Figure 9The left side shows a schematic diagram of the structure of the duct 210 of this design, and Table 5 shows the wind speed measurement data at each measuring point of this design. In this design, the upper edges of the air inlet 211 and air outlet 212 of the duct 210 are flush, and the lower edge of the air outlet 212 is lower than the lower edge of the air inlet 211, so that the top inner wall of the duct 210 is flush, while the bottom inner wall of the duct 210 slopes from the air inlet 211 towards the air outlet 212. This design can increase the cross-sectional size of the air outlet 212 to increase the cross-sectional area of ​​the air supply. The straight length of the duct 210 (e.g., ...) is... Figure 9 The height of the air inlet 211 (as indicated by the mark L) is 1146mm; Figure 9 The dimension of the outlet 121 of the centrifugal fan 120 (as shown by the mark H1) is equal to the dimension of the outlet 121 of the centrifugal fan 120, which is 250mm; the height dimension of the outlet 212 (as shown by the mark H1) is equal to the dimension of the outlet 121 of the centrifugal fan 120, which is 250mm; Figure 9 The diameter (as indicated by H2 in the middle) is 292 mm; the downward inclination angle of the bottom inner wall of the duct 210 is approximately 2.10°. Calculations show that the standard deviation of the wind speed measurement data is 3.36, and the average wind speed is approximately 19.19 MPa, which meets the design parameter requirements.

[0040] The test results above show that, taking centrifugal fan 120 as the baseline design, the standard deviation of the wind speed at outlet 121 of centrifugal fan 120 is about 3.59, and the standard deviations of the wind speed in designs A to D are about 4.53, 4.61, 3.48, and 3.36, respectively.

[0041] Comparing the standard deviations of wind speed between the baseline design and Design A, it can be seen that the standard deviation of Design A (4.53) is significantly higher than that of the baseline design (3.59). This indicates that although the horn-shaped structure can effectively expand the cross-sectional size of the air outlet 212, it is prone to causing uneven velocity distribution during airflow diffusion, resulting in poor improvement of wind speed uniformity and even exacerbating the dispersion of wind speed to a certain extent.

[0042] Comparing the standard deviations of wind speed in the baseline design, Design B, and Design C, it can be seen that the standard deviation of Design B (4.61) is larger than that of the baseline design, while the standard deviation of Design C (3.48) is lower than that of the baseline design. The main structural difference between Design B and Design C lies in the different inclination angles of the bottom inner wall. Both designs adopt a structure where the top inner wall is flush and the bottom inner wall slopes downward from the air inlet 211 towards the air outlet 212. Among them, Design C, within a reasonable inclination angle range, can effectively guide the airflow to be evenly distributed along the cross-section of the air outlet 212, which is beneficial to improving the wind speed uniformity of the air outlet 212.

[0043] Comparing the standard deviations of wind speed between the baseline design and design C, it can be seen that the standard deviation of design C (3.48) is lower than that of the baseline design (3.59). This indicates that when the inclination angle of the bottom inner wall of the duct 210 is controlled within a small range (≤7°), the gradually expanding structure can play a moderate rectification role in the airflow and has a positive effect on improving the uniformity of wind speed.

[0044] Comparing the wind speed standard deviations of Design C and Design D, it can be seen that the standard deviation of Design D (3.36) is further lower than that of Design C (3.48), making it the optimal value among all schemes. The downward inclination angles of the bottom inner wall of the duct 210 in Design C and Design D are approximately 7.11° and 2.10°, respectively. Without changing the straight length of the duct 210 and the size of the outlet 212, Design D increases the height of the inlet 211 and correspondingly reduces the inclination angle of the bottom inner wall, making the flow channel shape smoother and the airflow transition smoother, thereby further improving the wind speed uniformity of the outlet 212.

[0045] Based on the above analysis, the inclination angle of the bottom inner wall is a key structural parameter affecting the uniformity of air velocity at the air outlet 212. By keeping the top inner wall flush and appropriately increasing the height of the air inlet 211 to reduce the inclination angle of the bottom inner wall, the uniformity of air velocity distribution at the air outlet 212 cross-section can be effectively improved without increasing the overall length of the equipment.

[0046] Please refer to Figure 2 or Figure 3 In some preferred examples, the angle at which the bottom inner wall of the duct 210 is inclined from the air inlet 211 toward the air outlet 212 (e.g.) Figure 2 or Figure 3 The angle (indicated by the mark R) is 2.10°±0.50°, such as 1.60°, 1.75°, 2.00°, 2.35° or 2.60°, which can make the air outlet 212 of the air duct 210 have better air velocity uniformity and meet the test requirements.

[0047] Please refer to Figure 9 In a preferred example, the straight-line distance between the air inlet 211 and the air outlet 212 (e.g.) Figure 9 The height dimension of the air inlet 211 (as indicated by the mark L) is 1146±5mm. Figure 9 The height dimension of the air outlet 212 (as shown by the mark H1) is 250±5mm. Figure 9 The length (as shown by H2 in the figure) is 292±5mm. This allows the straight length of the duct assembly 200 to be controlled within 1200mm, which is beneficial for adapting to space-constrained engineering applications.

[0048] The air inlet 211 and the air outlet 101 are the same size. Without changing the straight dimension of the air duct 210 and the height dimension of the air outlet 212, the bottom inner wall inclination angle of the air duct 210 can be minimized, and better air outlet uniformity can be obtained.

[0049] Based on the above basic structural design, this embodiment can also provide the following optimization design directions.

[0050] Please refer to Figure 2 and Figure 3 For the air duct assembly 200, the air duct 210 includes a nested inner tube 214 and an outer tube 215. The structure of the inner tube 214 is as described above, that is, the top inner wall is flat and the bottom inner wall slopes downward from the air inlet 211 to the air outlet 212. The outer tube 215 is mainly used to nest and protect the inner tube 214 to avoid damage to the inner tube 214 during transportation, assembly or use. The structure of the outer tube 215 can be determined according to the actual application requirements. For example, the outer tube 215 is a cuboid structure.

[0051] In some applications, the inner tube 214 is a one-piece structure. Compared to riveting or threaded connections, this one-piece structure maintains the smoothness and straightness of the inner tube 214's wall surface, reducing the impact of unevenness on airflow. Alternatively, in other applications, the inner tube 214 is a fully welded sheet metal structure. The welds in this structure are located on the outer wall of the inner tube 214 to ensure a smooth and straight inner wall, further minimizing the impact of unevenness on airflow.

[0052] Furthermore, the inner tube 214 and the outer tube 215 are provided with a sealing step recess 216 on one side of the air inlet 211. The sealing step recess 216 can seal the connection between the air source assembly 100 and the air duct assembly 200. Specifically, the sealing step recess 216 has multiple stepped contact surfaces. Through the multi-stage contact of multiple stepped contact surfaces, the sealing contact area can be effectively increased, the risk of air leakage at the connection can be reduced, and the airflow inside the air source assembly 100 will not be unexpectedly disturbed due to the presence of connection gaps.

[0053] Please refer to Figure 2 A grid 230 is installed at the connection between the air source component 100 and the air duct component 200. The grid 230 has a structure with multiple grid holes, which can change the laminar air generated by the air source component 100 into turbulent air, divide the airflow, and achieve uniform distribution of airflow on the cross section, which is beneficial to enhance the uniformity of wind speed.

[0054] Please refer to Figure 1A quick-release structure 240 connects the air source assembly 100 and the air duct assembly 200, and movable guide rails 250 are installed on the bottom or sides of the air duct assembly 200. The quick-release structure 240 allows for rapid connection and separation of the air source assembly 100 and the air duct assembly 200, exposing the grille 230, thus allowing for the replacement of the grille 230 with different numbers of grille holes according to actual applications. For example, if the grille 230 is not needed, a single-hole grille can be selected; in this case, the hollow structure of the grille 230 does not obstruct the airflow path. If the grille 230 is needed to enhance the uniformity of airflow, a grille 230 with 4 holes, 8 holes, or more holes can be selected. The movable guide rails 250 guide the movement of the air duct assembly 200, ensuring that the installation angle of the air duct assembly 200 meets expectations, thereby ensuring the uniformity of airflow.

[0055] For acoustic testing of electronic products, it is necessary to minimize the noise of the testing equipment itself to improve the accuracy of test results. Therefore, please refer to... Figure 2 In some application examples, a first sound insulation material 220 is filled inside the duct assembly 200 and between the inner tube 214 and the outer tube 215; or, in other application examples, a second sound insulation material 130 is filled inside the air source assembly 100; or, in still other application examples, the first sound insulation material 220 is filled inside the duct assembly 200 and between the inner tube 214 and the outer tube 215, and the second sound insulation material 130 is filled inside the air source assembly 100. The first sound insulation material 220 can be a structure such as sponge, foam, or a perforated board to reduce wind noise generated by airflow or noise generated by vibration of the duct 210.

[0056] Please refer to Figure 3 Based on the same technical concept described above, this embodiment also provides an air duct 210. The air duct 210 is provided with an air inlet 211, an air outlet 212, and a flow equalization section 213 located between the air inlet 211 and the air outlet 212. The upper edges of the air inlet 211 and the air outlet 212 are flush, and the lower edge of the air outlet 212 is lower than the lower edge of the air inlet 211, so that the top inner wall of the flow equalization section 213 is flush, while the bottom inner wall of the flow equalization section 213 slopes from the air inlet 211 toward the air outlet 212. Details not covered in this embodiment of the air duct 210 can be found above and will not be repeated here.

[0057] The top inner wall of the air duct 210 is flush, while the bottom inner wall slopes from the air inlet 211 towards the air outlet 212, forming an asymmetrical flow channel structure. This causes the cross-sectional area of ​​the air duct 210 to gradually increase along the airflow direction. The guiding effect of the sloped bottom wall guides the airflow to expand along the wall, which, combined with the axial constraint of the flush top wall, eliminates the difference in air velocity between the upper and lower directions of the outlet cross-section. Thus, a uniform and stable airflow distribution is achieved within a limited length space, while also expanding the outlet area, meeting the testing requirements of portable electronic products in windy and noisy environments.

[0058] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An acoustic testing simulation device, characterized in that, include: The air source component (100) is provided with an air outlet (101). A duct assembly (200) is connected to the air outlet (101) of the air source assembly (100). The duct assembly (200) is provided with a duct pipe (210). The duct pipe (210) is provided with an air inlet (211), an air outlet (212), and a flow equalization section (213) located between the air inlet (211) and the air outlet (212). The upper edges of the air inlet (211) and the air outlet (212) are flush, and the lower edge of the air outlet (212) is lower than the lower edge of the air inlet (211) so that the top inner wall of the flow equalization section (213) is flush, and the bottom inner wall of the flow equalization section (213) is inclined from the air inlet (211) toward the air outlet (212).

2. The acoustic testing simulation device according to claim 1, characterized in that, The bottom inner wall of the air duct (210) is inclined at an angle of 2.10°±0.50° from the air inlet (211) toward the air outlet (212).

3. The acoustic testing simulation device according to claim 1 or 2, characterized in that, The straight-line distance between the air inlet (211) and the air outlet (212) is 1146±5mm, the height of the air inlet (211) is 250±5mm, and the height of the air outlet (212) is 292±5mm.

4. The acoustic testing simulation device according to claim 3, characterized in that, The air inlet (211) and the air outlet (101) are the same size.

5. The acoustic testing simulation device according to claim 1 or 4, characterized in that, The air duct (210) includes a nested inner tube (214) and an outer tube (215); the inner tube (214) is an integral structure, or the inner tube (214) is a sheet metal fully welded structure.

6. The acoustic testing simulation device according to claim 5, characterized in that, The inner tube (214) and the outer tube (215) are provided with a sealing step recess (216) on one side of the air inlet (211).

7. The acoustic testing simulation device according to claim 1 or 6, characterized in that, A grid mesh (230) is installed at the connection between the air source component (100) and the air duct component (200).

8. The acoustic testing simulation device according to claim 7, characterized in that, A quick-release structure (240) connects the air source assembly (100) and the air duct assembly (200), and a movable guide rail (250) is installed on the bottom or both sides of the air duct assembly (200).

9. The acoustic testing simulation device according to claim 5, characterized in that, The air duct assembly (200) is filled with a first sound insulation material (220) between the inner tube (214) and the outer tube (215). And / or, the air source assembly (100) is filled with a second sound insulation material (130).

10. A type of air duct, characterized in that, The air duct (210) is provided with an air inlet (211), an air outlet (212), and a flow equalization section (213) located between the air inlet (211) and the air outlet (212). The upper edges of the air inlet (211) and the air outlet (212) are flush, and the lower edge of the air outlet (212) is lower than the lower edge of the air inlet (211) so that the top inner wall of the flow equalization section (213) is flush, while the bottom inner wall of the flow equalization section (213) is inclined from the air inlet (211) toward the air outlet (212).

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