Cooling fan noise reduction device

Abstract

This invention relates to the field of wind power generation technology and discloses a noise reduction device for a cooling fan, comprising a fan casing, a noise-reducing impeller, an outlet sound-absorbing duct, a sound-absorbing material layer, and a sound-permeable protective layer. The fan casing has an air inlet and an air outlet; the noise-reducing impeller is rotatably disposed within the fan casing; a drive motor is connected to the noise-reducing impeller; the outlet sound-absorbing duct is disposed on the air outlet side of the fan casing and fixedly connected to the fan casing, forming an airflow channel communicating with the air outlet; the sound-absorbing material layer is disposed on the inner wall of the outlet sound-absorbing duct; and the sound-permeable protective layer is disposed on the side of the sound-absorbing material layer near the airflow channel. This disclosed device reduces noise at the source through the noise-reducing impeller and absorbs noise along the propagation path through the outlet sound-absorbing duct and the sound-absorbing material layer, effectively reducing the operating noise of the cooling fan while ensuring cooling and heat dissipation requirements.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation technology, and specifically relates to a noise reduction device for cooling fans. Background Technology

[0002] In related technologies, generator cooling fans are mostly designed with impellers to meet heat dissipation requirements, resulting in insufficient aerodynamic noise control. Laying sound-absorbing materials inside the nacelle is difficult to precisely target the cooling fan, a localized noise source, and the materials are prone to attenuation and detachment over long-term operation. External silencers increase size and are difficult to install due to the limited space in the nacelle. Optimizing only the impeller without addressing the propagation path has limited noise reduction effects. Modifying the original installation interface or ventilation cross-section is difficult on-site and may affect the original heat dissipation performance, hindering widespread application. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art. To this end, embodiments of the present invention provide a cooling fan noise reduction device that can reduce the aerodynamic noise generated by the operation of the cooling fan.

[0004] The cooling fan noise reduction device of this invention includes:

[0005] A fan housing having an air inlet and an air outlet; A noise-reducing impeller, which is rotatably disposed within the fan housing; A drive motor is connected to the noise-reducing impeller and is used to drive the noise-reducing impeller to rotate; An outlet sound-absorbing duct is provided on the air outlet side of the fan housing and is fixedly connected to the fan housing. An airflow channel communicating with the air outlet is formed inside the outlet sound-absorbing duct. A sound-absorbing material layer is disposed on the inner wall of the outlet sound-absorbing air duct; A sound-permeable protective layer is provided on the side of the sound-absorbing material layer near the airflow channel, and is used to protect and fix the sound-absorbing material layer.

[0006] The cooling fan noise reduction device of this invention reduces rotational aerodynamic noise from the noise-generating end through a noise-reducing impeller, and absorbs and dissipates noise along the propagation path through the sound-absorbing duct at the outlet and the sound-absorbing material layer on its inner wall, achieving a synergistic effect of noise reduction at the source and noise reduction along the propagation path. The sound-permeable protective layer allows sound waves to enter the interior of the sound-absorbing material layer, while also compressing, limiting, and protecting the sound-absorbing material layer, preventing it from falling off or shifting under airflow erosion and long-term operational vibration.

[0007] In some embodiments, the cooling fan noise reduction device further includes an inlet sound-absorbing duct, which is located on the air inlet side of the fan housing and is fixedly connected to the fan housing. An airflow channel communicating with the air inlet is formed inside the inlet sound-absorbing duct. The inner wall of the inlet sound-absorbing duct is provided with the sound-absorbing material layer, and the side of the sound-absorbing material layer near the airflow channel is provided with the sound-permeable protective layer.

[0008] The noise reduction device for cooling fans in this embodiment of the invention improves the noise reduction effect by setting an inlet sound-absorbing duct and an outlet sound-absorbing duct on the air inlet and outlet sides of the fan casing, respectively. This allows noise to be absorbed and dissipated before entering the fan casing and after exiting the fan casing.

[0009] In some embodiments, the flow cross-section of the inlet sound-absorbing duct gradually decreases in the direction toward the air inlet, and / or the flow cross-section of the outlet sound-absorbing duct gradually decreases in the direction toward the air outlet.

[0010] The cooling fan noise reduction device of this invention, by gradually changing the flow cross-section of the inlet and outlet sound-absorbing ducts, can guide the airflow to transition smoothly, reduce the local resistance loss of the airflow when entering and exiting the fan casing, and the gradually shrinking cross-section structure also helps to increase the contact length between the sound-absorbing material layer and the airflow, thereby enhancing the noise reduction effect.

[0011] In some embodiments, the noise-reducing impeller includes a hub and a plurality of blades evenly distributed circumferentially, wherein the leading edge of the blade has a smooth transition structure, the trailing edge of the blade has a gradually thinning transition structure, and the blade body forms a twisted transition in the radial direction.

[0012] The noise reduction device for cooling fans in this invention reduces intake impact and local pressure surges through a smooth transition structure at the leading edge of the blades; it weakens wake detachment and vortex separation through a gradually thinning transition structure at the trailing edge of the blades; and it improves the airflow inflow state at different radius positions through a twisted transition structure on the blade body, allowing the airflow to flow more smoothly along the blade surface. Through the synergistic effect of the above blade design, the aerodynamic noise generated by impeller rotation can be reduced while ensuring the required airflow and air pressure of the cooling fan, which helps to weaken the peak noise near the blade passage frequency and its harmonics.

[0013] In some embodiments, the sound-permeable protective layer is a perforated plate, and a fixing structure is provided between the sound-permeable protective layer and the inner wall of the outlet sound-absorbing duct to clamp and fix the sound-absorbing material layer.

[0014] The noise reduction device for cooling fans in this embodiment of the invention sets the sound-permeable protective layer as a perforated plate. Sound waves can enter the interior of the sound-absorbing material layer through the perforations and be dissipated. At the same time, the perforated plate has a certain rigidity and strength, which can effectively withstand the pressure generated by the airflow and prevent the sound-absorbing material layer from deforming or breaking during long-term operation.

[0015] In some embodiments, the outlet sound-absorbing duct is detachably connected to the fan housing.

[0016] The cooling fan noise reduction device of this invention has a detachable connection between the outlet sound-absorbing duct and the fan casing, which facilitates the inspection, replacement or cleaning of the internal sound-absorbing material layer and sound-permeable protective layer, thus improving the maintainability of the device.

[0017] In some embodiments, the outlet sound-absorbing duct and the fan housing are an integral structure.

[0018] The cooling fan noise reduction device of this invention reduces the number of connecting parts, reduces assembly errors, and improves structural integrity and sealing by setting the outlet sound-absorbing air duct and the fan housing as an integrated structure.

[0019] In some embodiments, the sound-absorbing material layer is continuously arranged along the airflow direction on the inner wall of the outlet sound-absorbing duct, and the sound-absorbing material layer is attached to or embedded in the inner wall of the outlet sound-absorbing duct.

[0020] The cooling fan noise reduction device of this invention increases the contact area and action distance between sound waves and the sound-absorbing material by continuously arranging the sound-absorbing material layer along the airflow direction, thereby improving the absorption efficiency of mid-to-high frequency aerodynamic noise. The sound-absorbing material layer is attached to or embedded in the inner wall of the outlet sound-absorbing duct, without significantly occupying the main airflow channel, thus avoiding a significant increase in wind resistance or a reduction in cooling airflow, ensuring the generator's cooling and heat dissipation requirements while meeting the noise reduction effect. Attached Figure Description

[0021] Figure 1 This is an overall schematic diagram of the present invention.

[0022] Figure 2 This is a schematic diagram of the noise-reducing impeller in this invention.

[0023] Figure 3 This is a schematic diagram of the blade structure in this invention.

[0024] Figure 4 This is a schematic diagram showing the distribution of the sound-permeable material layer and the sound-absorbing material layer in this invention.

[0025] Figure label: 1. Fan casing; 11. Air inlet; 12. Air outlet; 2. Noise-reducing impeller; 21. Hub; 22. Blade; 221. Leading edge; 222. Trailing edge; 223. Blade body; 3. Drive motor; 4. Exit sound-absorbing air duct; 41. Airflow channel; 5. Sound-absorbing material layer; 6. Sound-permeable protective layer; 7. Imported sound-absorbing air duct; 71. Airflow channel. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] The cooling fan noise reduction device of this invention can be applied to the generator cooling system of a wind turbine generator set to reduce the aerodynamic noise generated by the cooling fan while ensuring cooling and heat dissipation requirements. Of course, this device can also be applied to other scenarios that require balancing ventilation and heat dissipation with noise reduction.

[0028] like Figure 1-4 As shown, the cooling fan noise reduction device of this embodiment includes a fan housing 1, a noise reduction impeller 2, a drive motor 3, an outlet sound-absorbing air duct 4, a sound-absorbing material layer 5, and a sound-permeable protective layer 6.

[0029] The fan casing 1 has an air inlet 11 and an air outlet 12. The air inlet 11 is used to introduce cooling airflow, and the air outlet 12 is used to discharge cooling airflow. A noise-reducing impeller 2 is rotatably mounted inside the fan casing 1. A drive motor 3 is connected to the noise-reducing impeller 2 to drive its rotation and generate cooling airflow. An outlet sound-absorbing duct 4 is located on the outlet side of the fan casing 1 and is fixedly connected to it. An airflow channel 41 communicating with the air outlet 12 is formed within the outlet sound-absorbing duct 4. A sound-absorbing material layer 5 is disposed on the inner wall of the outlet sound-absorbing duct 4, and a sound-permeable protective layer 6 is disposed on the side of the sound-absorbing material layer 5 near the airflow channel 41, for protecting and fixing the sound-absorbing material layer 5.

[0030] The cooling fan noise reduction device of this invention reduces rotational aerodynamic noise from the noise-generating end through the noise-reducing impeller 2, and absorbs and dissipates noise along the propagation path through the outlet sound-absorbing duct 4 and the sound-absorbing material layer 5 on its inner wall, achieving a synergistic effect of noise reduction at the source and noise reduction along the propagation path. The sound-permeable protective layer 6 allows sound waves to enter the interior of the sound-absorbing material layer 5, while also compressing, limiting, and protecting the sound-absorbing material layer 5, preventing it from falling off or shifting under airflow scouring and long-term operational vibration.

[0031] Specifically, during operation, the drive motor 3 rotates the noise-reducing impeller 2. Cooling airflow enters the fan casing 1 through the inlet 11, is pressurized by the noise-reducing impeller 2, and then enters the airflow channel 41 of the outlet sound-absorbing duct 4 before being discharged. The noise-reducing impeller 2 reduces airflow impact and flow separation through its low-noise blade shape, thereby reducing rotational aerodynamic noise from the noise-generating end. When noise enters the outlet sound-absorbing duct 4 with the cooling airflow, the sound waves pass through the sound-permeable protective layer 6 and enter the interior of the sound-absorbing material layer 5. Frictional dissipation and thermal viscosity loss occur in the porous material, thereby reducing the noise intensity propagating along the duct.

[0032] In some embodiments, the cooling fan noise reduction device further includes an inlet sound-absorbing duct 7, which is located on the air inlet side of the fan housing 1 and is fixedly connected to the fan housing 1. An airflow channel 71 communicating with the air inlet 11 is formed inside the inlet sound-absorbing duct 7. A sound-absorbing material layer 5 is provided on the inner wall of the inlet sound-absorbing duct 7, and a sound-permeable protective layer 6 is provided on the side of the sound-absorbing material layer 5 near the airflow channel 71.

[0033] The noise reduction device for cooling fans in this embodiment of the invention improves the noise reduction effect by setting an inlet sound-absorbing duct 7 and an outlet sound-absorbing duct 4 on the air inlet and outlet sides of the fan housing 1, respectively. This allows noise to be absorbed and dissipated before entering the fan housing 1 and after exiting the fan housing 1.

[0034] In some embodiments, the flow cross section of the inlet sound-absorbing duct 7 gradually decreases in the direction toward the air inlet 11, and / or the flow cross section of the outlet sound-absorbing duct 4 gradually decreases in the direction toward the air outlet 12.

[0035] The cooling fan noise reduction device of this invention, by gradually changing the flow cross-section of the inlet sound-absorbing duct 7 and the outlet sound-absorbing duct 4, can guide the airflow to transition smoothly, reduce the local resistance loss of the airflow when entering and exiting the fan housing 1, and the gradually shrinking cross-section structure also helps to increase the contact length between the sound-absorbing material layer 5 and the airflow, thereby enhancing the noise reduction effect.

[0036] Specifically, the end of the inlet sound-absorbing duct 7 furthest from the air inlet 11 has a larger inlet cross-section, while the end closest to the air inlet 11 has a smaller outlet cross-section. As the airflow moves through the inlet sound-absorbing duct 7, its velocity gradually increases, resulting in smooth flow. Similarly, the end of the outlet sound-absorbing duct 4 closest to the air outlet 12 has a smaller inlet cross-section, while the end furthest from the air outlet 12 has a larger outlet cross-section. As the airflow moves through the outlet sound-absorbing duct 4, its velocity gradually decreases, which is beneficial for the full absorption of noise.

[0037] In some embodiments, the noise-reducing impeller 2 includes a hub 21 and a plurality of blades 22 evenly distributed along the circumference. The leading edge 221 of the blades 22 has a smooth transition structure, the trailing edge 222 of the blades 22 has a gradually thinning transition structure, and the blade body 223 of the blades 22 forms a twisted transition along the radial direction.

[0038] The noise reduction device for the cooling fan in this embodiment of the invention reduces intake impact and local pressure surges through the smooth transition structure of the leading edge 221 of the blade 22; it weakens wake detachment and vortex separation through the gradually thinning transition structure of the trailing edge 222 of the blade 22; and it improves the airflow injection state at different radius positions through the bending and twisting transition structure of the blade body 223, making the airflow flow more smoothly along the surface of the blade 22. Through the synergistic effect of the above blade design, the aerodynamic noise generated by the impeller rotation can be reduced while ensuring the required air volume and air pressure of the cooling fan, which is beneficial to weakening the peak noise near the blade passage frequency and its harmonics.

[0039] In some embodiments, the sound-permeable protective layer 6 is a perforated plate, and there is a fixing structure between the sound-permeable protective layer 6 and the inner wall of the outlet sound-absorbing air duct 4 to clamp and fix the sound-absorbing material layer 5.

[0040] The noise reduction device for cooling fans in this embodiment of the invention sets the sound-permeable protective layer 6 as a perforated plate. Sound waves can enter the sound-absorbing material layer 5 through the perforations and be dissipated. At the same time, the perforated plate has a certain rigidity and strength, which can effectively withstand the pressure generated by the airflow and prevent the sound-absorbing material layer 5 from deforming or breaking during long-term operation.

[0041] Specifically, the fixing structure can include screws, pressure plates, riveting, or grooved limiting mechanisms. The sound-absorbing material layer 5 is pressed between the sound-permeable protective layer 6 and the inner wall of the outlet sound-absorbing duct 4, forming a reliable clamping fixation. The sound-permeable protective layer 6 can also be a metal mesh or other protective structure with sound-permeable function.

[0042] In some embodiments, the outlet sound-absorbing duct 4 is detachably connected to the fan housing 1.

[0043] The cooling fan noise reduction device of this embodiment of the invention features a detachable connection between the outlet sound-absorbing duct 4 and the fan housing 1, facilitating the inspection, replacement, or cleaning of the internal sound-absorbing material layer 5 and the sound-permeable protective layer 6, thus improving the maintainability of the device. Simultaneously, the inlet sound-absorbing duct 7 can also be detachably connected to the fan housing 1, allowing for independent replacement or maintenance of the sound-absorbing structure on the air inlet side.

[0044] Specifically, the outlet sound-absorbing duct 4 can be connected to the fan casing 1 via mechanical connections such as flanges, connecting plates, or bolts. Flange connections have the advantages of simple structure, accurate positioning, and convenient assembly and disassembly.

[0045] In some embodiments, the outlet sound-absorbing duct 4 and the fan housing 1 are an integral structure.

[0046] The cooling fan noise reduction device of this invention reduces the number of connecting parts, reduces assembly errors, and improves structural integrity and sealing by setting the outlet sound-absorbing air duct 4 and the fan housing 1 as an integral structure.

[0047] In some embodiments, such as Figure 1 As shown, the sound-absorbing material layer 5 is continuously arranged along the airflow direction on the inner wall of the outlet sound-absorbing duct 4, and the sound-absorbing material layer 5 is attached to or embedded in the inner wall of the outlet sound-absorbing duct 4.

[0048] The cooling fan noise reduction device of this embodiment of the invention increases the contact area and action distance between sound waves and sound-absorbing materials by continuously arranging the sound-absorbing material layer 5 along the airflow direction, thereby improving the absorption efficiency of mid-to-high frequency aerodynamic noise. The sound-absorbing material layer 5 is attached to or embedded in the inner wall of the outlet sound-absorbing duct 4, without significantly occupying the main airflow channel 41, thus avoiding a significant increase in wind resistance or a reduction in cooling airflow, ensuring the generator's cooling and heat dissipation requirements while meeting the noise reduction effect.

[0049] Specifically, the sound-absorbing material layer 5 uses a porous sound-absorbing material that is heat-resistant, moisture-resistant, and flame-retardant to meet the requirements of the long-term operating environment of the wind turbine nacelle. The thickness of the sound-absorbing material layer 5 is determined based on the spatial dimensions of the outlet sound-absorbing duct 4, the target noise reduction frequency band, and the cooling airflow requirements.

[0050] In some embodiments, the external dimensions, mounting boundaries, and mounting holes of the fan housing 1 are matched with those of the original generator cooling fan, so that the cooling fan noise reduction device can be used as a replacement noise reduction component for the original generator cooling fan.

[0051] The cooling fan noise reduction device of this invention can directly replace the original cooling fan without changing the original nacelle structure, cooling air duct, electrical connection and maintenance space by maintaining the installation interface that matches the original cooling fan, thus reducing the amount of on-site modification and making it suitable for on-site noise reduction retrofit of existing wind turbine units.

[0052] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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 limitations on this invention.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0056] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A noise reduction device for a cooling fan, characterized in that, include: The fan housing (1) has an air inlet (11) and an air outlet (12). Noise-reducing impeller (2), which is rotatably disposed inside the fan housing (1); A drive motor (3) is connected to the noise-reducing impeller (2) and is used to drive the noise-reducing impeller (2) to rotate; The outlet sound-absorbing duct (4) is located on the air outlet side of the fan housing (1) and is fixedly connected to the fan housing (1). An airflow channel (41) communicating with the air outlet (12) is formed inside the outlet sound-absorbing duct (4). A sound-absorbing material layer (5) is disposed on the inner wall of the outlet sound-absorbing duct (4); Sound-permeable protective layer (6) is provided on the side of the sound-absorbing material layer (5) near the airflow channel (41) for protecting and fixing the sound-absorbing material layer (5).

2. The cooling fan noise reduction device according to claim 1, characterized in that, It also includes an inlet sound-absorbing duct (7), which is located on the air inlet side of the fan housing (1) and is fixedly connected to the fan housing (1). An airflow channel (71) communicating with the air inlet (11) is formed inside the inlet sound-absorbing duct (7). The inner wall of the inlet sound-absorbing duct (7) is provided with the sound-absorbing material layer (5), and the sound-absorbing material layer (5) is provided with the sound-permeable protective layer (6) on the side of the sound-absorbing material layer (5) close to the airflow channel (71).

3. The cooling fan noise reduction device according to claim 2, characterized in that, The flow cross section of the inlet sound-absorbing duct (7) gradually decreases in the direction toward the air inlet (11), and / or the flow cross section of the outlet sound-absorbing duct (4) gradually decreases in the direction toward the air outlet (12).

4. The cooling fan noise reduction device according to claim 1, characterized in that, The noise reduction impeller (2) includes a hub (21) and multiple blades (22) evenly distributed along the circumference. The leading edge (221) of the blade (22) has a smooth transition structure, the trailing edge (222) of the blade (22) has a gradually thinning transition structure, and the blade body (223) of the blade (22) forms a twisted transition along the radial direction.

5. The cooling fan noise reduction device according to claim 1, characterized in that, The sound-permeable protective layer (6) is a perforated plate. The sound-permeable protective layer (6) and the inner wall of the outlet sound-absorbing duct (4) have a fixed structure to clamp and fix the sound-absorbing material layer (5).

6. The cooling fan noise reduction device according to claim 1, characterized in that, The outlet sound-absorbing duct (4) is detachably connected to the fan housing (1).

7. The cooling fan noise reduction device according to claim 1, characterized in that, The outlet sound-absorbing air duct (4) and the fan housing (1) are an integral structure.

8. The cooling fan noise reduction device according to claim 1, characterized in that, The sound-absorbing material layer (5) is continuously arranged along the airflow direction on the inner wall of the outlet sound-absorbing duct (4), and the sound-absorbing material layer (5) is attached to or embedded in the inner wall of the outlet sound-absorbing duct (4).

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