Impeller, centrifugal fan and air conditioning device
By designing a serrated structure at the trailing edge of the blades, the aerodynamic noise problem of the centrifugal fan is solved by suppressing laminar boundary layer splitting and changing the vortex shedding mode. This achieves noise reduction and flow optimization while maintaining airflow and improving durability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2026-03-31
AI Technical Summary
The aerodynamic noise of existing centrifugal fans is mainly caused by the shedding of vortices from the trailing edge of the blades, resulting in high noise intensity and concentrated frequency, which can easily cause resonance. Existing technologies lack effective flow control measures.
A serrated structure is designed at the trailing edge of the blade, including an outer extension and an inner tangent. The serrated structure suppresses laminar boundary layer splitting, changes the vortex shedding mode, reduces the intensity of separated vortices, and changes vortex shedding from concentrated to discrete, thereby reducing the noise frequency.
It effectively reduces fan noise, avoids noise generation, maintains or increases airflow, optimizes flow characteristics, and enhances blade durability and reliability.
Smart Images
Figure CN224064570U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of air conditioning technology, such as to an impeller, a centrifugal fan, and an air conditioning device. Background Technology
[0002] Currently, the main noise sources of centrifugal fans include aerodynamic noise, electromagnetic noise, and mechanical noise. Among these, aerodynamic noise is far greater than the other noises, thus playing a decisive role in the overall noise level of the fan. Aerodynamic noise is primarily vortex noise (also known as eddy current noise or turbulent flow noise). This noise is mainly caused by the shedding of vortices from the laminar boundary layer (a layer with high molecular viscous stress near a given boundary due to a large velocity gradient along the normal direction of the boundary surface) on the fan blade surface. Specifically, when the aerodynamic drag of the fan is high, the relative angle between the blades and the airflow is too large, leading to strong vortex separation at the blade trailing edge. For existing ordinary centrifugal fans, due to the lack of any flow control measures, the intensity of the vortices shedding from the blade trailing edge is relatively high, resulting in high noise intensity. Furthermore, the frequency of the shedding vortices is relatively concentrated, forming a specific frequency sound. When this frequency resonates with the natural frequency of the human ear, it can cause significant discomfort, such as irritability.
[0003] Therefore, there is a need to provide a centrifugal fan that uses certain technical means to reduce aerodynamic noise, thereby achieving noise reduction.
[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content
[0005] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.
[0006] This disclosure provides an impeller, a centrifugal fan, and an air conditioning device to reduce fan noise.
[0007] In some embodiments, the impeller includes:
[0008] The blade has a serrated edge.
[0009] The serrated structure is formed by extending inward from the trailing edge of the blade, either partially or entirely.
[0010] In some embodiments, the serrated structure includes:
[0011] The extension is a structure that extends outward from the trailing edge of the blade;
[0012] The inner part is integrally formed with the outer part and is formed by extending inward from the trailing edge of the blade.
[0013] The height of the extension portion is greater than or equal to the height of the inscribed portion.
[0014] In some embodiments, the ratio of the height of the extension portion to the tooth height of the serrated structure is 0.5 to 0.7.
[0015] In some embodiments, the tips of the teeth in the serrated structure are sharp-angled.
[0016] In some embodiments, the root of the serrated structure is arc-shaped.
[0017] In some embodiments, the blade is arc-shaped, and the serrated structure is set at a preset angle to the normal of the corresponding point of the blade.
[0018] In some embodiments, the tooth height dimension of the serrated structure is less than or equal to the tooth width dimension.
[0019] In some embodiments, it also includes:
[0020] Support plates are located at both ends of the impeller and have a ring-shaped structure;
[0021] Multiple blades are arranged around the support plate.
[0022] In some embodiments, the centrifugal fan includes the impeller provided in the foregoing embodiments.
[0023] In some embodiments, the air conditioning device includes a centrifugal fan as described in the foregoing embodiments.
[0024] The impeller, centrifugal fan, and air conditioning device provided in this disclosure can achieve the following technical effects:
[0025] Designing the blade trailing edge with a serrated structure can suppress laminar boundary layer splitting at the blade trailing edge, reducing the intensity of separated vortices and thus achieving the goal of fan noise reduction. The serrated blade trailing edge can also transform concentrated vortex shedding into discrete vortex shedding, and reduce the size of the shedding vortices, thereby optimizing flow and avoiding noise generation, achieving the purpose of noise reduction and frequency modulation. Furthermore, the serrated structure extends partially or entirely inward from the blade trailing edge, ensuring airflow while achieving noise reduction.
[0026] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description
[0027] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:
[0028] Figure 1 This is a schematic diagram of a blade structure provided in an embodiment of this disclosure;
[0029] Figure 2 This is a partial structural schematic diagram of the blade provided in an embodiment of this disclosure;
[0030] Figure 3 This is a partial structural schematic diagram of the blade provided in another embodiment of the present disclosure;
[0031] Figure 4 This is a partial structural schematic diagram of the blade provided in another embodiment of this disclosure.
[0032] Figure label:
[0033] 10: Leaf blade; 101: Tail margin;
[0034] 20: Serrated structure; 201: Extension; 202: Incision; 203: Tooth tip; 204: Tooth root. Detailed Implementation
[0035] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.
[0036] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.
[0037] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.
[0038] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.
[0039] Unless otherwise stated, the term "multiple" means two or more.
[0040] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.
[0041] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.
[0042] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.
[0043] Combination Figures 1 to 4 As shown, an embodiment of this disclosure provides an impeller including blades 10, the trailing edge 101 of the blades 10 being provided with a serrated structure 20; wherein, part or all of the serrated structure 20 is formed by extending inward from the trailing edge 101 of the blades 10.
[0044] The impeller includes multiple blades 10, which are arranged around the centerline of the impeller. The trailing edge 101 of the blades 10 on the outlet side is configured with a serrated structure 20. This suppresses laminar boundary layer splitting at the trailing edge 101 of the blades 10, reducing the intensity of separated vortices and thus achieving noise reduction. Furthermore, the serrated trailing edge 101 of the blades 10 can transform concentrated vortex shedding into discrete vortex shedding, and further reduce the size of the shed vortices, thereby optimizing flow and preventing noise generation, achieving noise reduction and frequency modulation.
[0045] The serrated structure 20 of the trailing edge 101 of the blade 10 extends inward from the trailing edge 101 of the blade 10, which can be understood as the serrated structure 20 extending along the bending direction of the blade 10 to the other side of the trailing edge 101 of the blade 10.
[0046] By employing the impeller provided in this embodiment, and configuring the trailing edge 101 of the blade 10 as a serrated structure 20, laminar boundary layer splitting at the trailing edge 101 of the blade 10 can be suppressed, reducing the intensity of the separated vortex, thereby achieving the purpose of fan noise reduction. The serrated structure 20 at the trailing edge 101 of the blade 10 can also transform concentrated vortex shedding into discrete vortex shedding, and reduce the size of the shedding vortices, thus optimizing flow and avoiding noise generation, achieving the purpose of noise reduction and frequency modulation. Furthermore, part or all of the serrated structure 20 extends inward from the trailing edge 101 of the blade 10, ensuring airflow while achieving noise reduction.
[0047] Optionally, the serrated structure 20 includes an extension portion 201 and an incision portion 202. The extension portion 201 is formed by extending outward from the trailing edge 101 of the blade 10. The incision portion 202 is integrally formed with the extension portion 201 and is formed by extending inward from the trailing edge 101 of the blade 10. The height of the extension portion 201 is greater than or equal to the height of the incision portion 202.
[0048] The extension portion 201 is formed by extending outward from the trailing edge 101 of the blade 10 along the extension direction of the blade 10, and the tangent portion 202 is formed by extending outward from the trailing edge 101 of the blade 10 along the extension direction of the blade 10 in a direction opposite to the trailing edge 101 of the blade 10. That is, it can be understood that the tangent portion 202 of the serrated structure 20 is formed by cutting the trailing edge 101 of the blade 10, while the extension portion 201 is formed by extending outward based on the blade 10.
[0049] For example, the height of the extension portion 201 accounts for 60% of the height of the serrated structure 20, and the height of the incision portion 202 accounts for 40% of the height of the serrated structure 20.
[0050] Simulation verification shows that it does not affect the airflow of the impeller assembled in the specific volute. The height of the extension 201 is less than or equal to 60% of the height of the serrated structure 20. The 40% serrated structure 20 is formed by cutting the initial blade 10. This design standard ensures that the impeller with the serrated structure 20 at the trailing edge 101 of the blade 10 has an airflow at the same rotational speed that is not lower than that of the original impeller.
[0051] The inner part 202 and the outer part 201 are integrally formed, which on the one hand provides better durability and reliability, reduces connection points and potential failure points; on the other hand, it reduces errors in the assembly process and eliminates the steps of assembling multiple parts, thereby improving the consistency and reliability of the product.
[0052] In addition, the integrated design of the sawtooth structure 20 helps to break up the detached vortex at the trailing edge 101, reduce the spanwise consistency of the vortex at the trailing edge 101, form vortex pairs between the sawtooths, broaden the distribution range of the detached vortex, and effectively change the flow state of the fluid at the trailing edge 101 of the wind turbine blade 10 from different incoming flow directions.
[0053] The height of the extension 201 is greater than or equal to the height of the incision 202, which helps the serrated structure 20 of the trailing edge 101 of the blade 10 to be embedded in the air duct and meet a certain proportion. For example, the serrated structure 20 of the trailing edge 101 of the blade 10 is embedded 30%-50% in the optimal air duct performance, and the length of the extension (extension 201) along the blade 10 profile compensates for the wind pressure loss and air volume loss caused by the serration of the blade 10. Compared with the original impeller, the air volume of the impeller with the added trailing edge 101 serrated structure 20 is not reduced at all, thus ensuring noise reduction after vortex breaking. The advantage of this design is that it ensures that both the air volume of the original impeller and the noise reduction effect obtained by the trailing edge 101 serrated structure 20 of the blade 10 are positive gains, thereby achieving the best noise reduction effect.
[0054] Optionally, the ratio of the height of the extension 201 to the tooth height of the serrated structure 20 is 0.5 to 0.7.
[0055] By designing the height ratio of the extension portion 201 to the tooth height of the serrated structure 20 to be 0.5 to 0.7, it can be understood that the ratio of the height of the extension portion 201 to the height of the serrated structure 20 is between 50% and 70%. This design ensures that the impeller with the added serrated structure 20 at the trailing edge 101 of the blade 10 does not have a lower airflow than the original impeller at the same rotational speed. The length portion of the blade 10 in the extension portion 201 compensates for the wind pressure and airflow losses caused by the serration of the blade 10; compared to the original impeller, the airflow of the impeller with the added trailing edge 101 serrated structure 20 is not reduced at all, thus ensuring noise reduction after vortex breaking. The advantage of this design is that it ensures that both the airflow of the original impeller and the noise reduction effect obtained from the trailing edge 101 serrated structure 20 of the blade 10 are positive gains, thereby achieving the best noise reduction effect.
[0056] Optionally, the tooth tips 203 of the serrated structure 20 are sharp-angled.
[0057] Setting the trailing edge 101 of the blade 10 as a serrated structure 20 can suppress laminar boundary layer splitting at the trailing edge 101 of the blade 10, reduce the intensity of the separation vortex, and thus achieve the purpose of wind turbine noise reduction. The sharp-angled structure of the tooth tip 203 helps the trailing edge 101 of the blade 10 to better break up the shedding vortex, reducing the size of the shedding vortex, thereby optimizing the flow, avoiding noise generation, and achieving the purpose of noise reduction and frequency modulation.
[0058] During manufacturing, the sharp-angled tooth tips have higher strength, are less prone to breakage, and have better rolling resistance, thus improving the durability of the blade 10. The sharper tooth tips of the sharp-angled structure help improve the efficiency of cutting or combing. It can be seen that the sharp-angled tooth tip 203 of the serrated structure 20 of the trailing edge 101 of the blade 10 can bring significant benefits in terms of reducing aerodynamic noise, improving flow characteristics, improving aerodynamic performance, and increasing durability.
[0059] Optionally, the root portion 204 of the serrated structure 20 has an arc-shaped structure.
[0060] By designing the root 204 of the serrated structure 20 to be arc-shaped, noise in the mid-to-high frequency range can be effectively reduced. This structure affects the aerodynamic noise of the blade 10 by influencing the development of spanwise vortices at the trailing edge 101, thereby reducing startup noise. Furthermore, it accelerates flow mixing and energy diffusion at the trailing edge 101, altering the unsteady vortex structure and vortex shedding frequency. This structure promotes the breaking up of spanwise vortices, transforming large-scale spanwise vortices into smaller-scale vortices, significantly reducing single-tone spike noise.
[0061] Optionally, the root 204 of the serrated structure 20 is chamfered, resulting in a non-sharp-angled structure. This effectively reduces noise in the mid-to-high frequency range. This structure affects the aerodynamic noise of the blade 10 by influencing the development of spanwise vortices at the trailing edge 101, thereby reducing startup noise. Furthermore, it accelerates flow mixing and energy diffusion at the trailing edge 101, altering the unsteady vortex structure and vortex shedding frequency. This structure significantly reduces single-tone spike noise by promoting the breaking up of spanwise vortices, transforming large-scale spanwise vortices into smaller-scale vortices.
[0062] Optionally, the blade 10 is arc-shaped, and the serrated structure 20 and the normal of the corresponding point of the blade 10 are set at a preset angle.
[0063] The curved blade 10 can improve flow separation within the inter-blade channel, thereby increasing the efficiency of the fan. In this embodiment, the blade 10 is a double-arc blade 10. The double-arc blade 10 allows for more freedom in design control of its central angle and camber, enhancing the design freedom of the inter-blade channel shape and making it more consistent with the flow characteristics of airflow within a multi-blade centrifugal fan. There is a synergistic effect between strength, stiffness, and durability in the structural design of the curved blade 10. With guaranteed strength and stiffness, the durability of the blade 10 is significantly improved. The double-arc blade 10 also exhibits superior aerodynamic performance, reducing flow losses. Therefore, the curved blade 10 has significant beneficial effects in reducing aerodynamic noise, improving flow characteristics, enhancing aerodynamic performance, strengthening dynamic adjustment capabilities, increasing structural strength and durability, reducing flow losses, and accelerating flow velocity.
[0064] The serrated structure 20 and the blade 10 have their corresponding points with the normals set at a preset angle. This can be understood as the serrated structure 20 having its hollowed-out portion and the blade 10 having its corresponding hollowed-out portion having their normals set at a preset angle. For example, the serrated structure 20 has its hollowed-out portion and the blade 10 having its corresponding hollowed-out portion having their normals set at 15°, thereby causing the airflow direction of the blade 10 to be obliquely offset from the serrated vortex, avoiding vertical cut-in to the airflow of the blade 10.
[0065] Optionally, the tooth height H of the serrated structure 20 is less than or equal to the tooth width D.
[0066] The serrated trailing edge 101 of the blade 10 enhances the turbulence characteristics in the trailing edge 101 region. Fluid flowing through the serrations significantly impacts the mainstream flow from the upper surface of the blade 10, thus helping to reduce aerodynamic noise. A smaller tooth height may reduce material consumption during manufacturing and, due to its relatively simple structure, may improve production efficiency. A smaller tooth height may also provide better structural stability, especially under dynamic loads. Therefore, dimensions in the serrated structure 20 where the tooth height is less than or equal to the tooth width can bring numerous beneficial effects, including reduced aerodynamic noise, improved aerodynamic performance, increased heat transfer efficiency, optimized structural design, reduced material consumption, increased production efficiency, and enhanced structural stability.
[0067] For example, the tooth height of the serrated structure 20 can be 1.8 mm and the tooth width can be 2.0 mm.
[0068] Optionally, the impeller further includes: a support plate located at both ends of the impeller and having an annular structure; wherein a plurality of blades 10 are arranged around the support plate.
[0069] The blades 10 are fixed by support plates, and the support plates and multiple surrounding blades 10 form an impeller. Support plates are provided at both ends of the blades 10, which not only improves the reliability of the blades 10 during use, but also increases the rigidity of the blades 10.
[0070] Combination Figures 1 to 4 As shown in the embodiments of this disclosure, a centrifugal fan is also provided, including the impeller provided in the above embodiments. The impeller includes blades 10, and the trailing edge 101 of the blades 10 is provided with a serrated structure 20; wherein, part or all of the serrated structure 20 is formed by extending inward from the trailing edge 101 of the blades 10.
[0071] By employing the centrifugal fan provided in this embodiment, the trailing edge 101 of the blade 10 is configured with a serrated structure 20, which can suppress laminar boundary layer splitting at the trailing edge 101 of the blade 10 and reduce the intensity of the separated vortices, thereby achieving the purpose of fan noise reduction. The serrated structure 20 at the trailing edge 101 of the blade 10 can also transform concentrated vortex shedding into discrete vortex shedding, and reduce the size of the shedding vortices, thus optimizing flow and avoiding noise generation, achieving the purpose of noise reduction and frequency modulation. Furthermore, part or all of the serrated structure 20 extends inward from the trailing edge 101 of the blade 10, ensuring airflow while achieving noise reduction.
[0072] Combination Figures 1 to 4 As shown in the embodiments of this disclosure, an air conditioning device is also provided, including the centrifugal fan provided in the above embodiments.
[0073] The centrifugal fan includes an impeller, which includes blades 10. The trailing edge 101 of the blades 10 has a serrated structure 20; wherein, part or all of the serrated structure 20 is formed by extending inward from the trailing edge 101 of the blades 10. Multiple blades 10 are arranged around the centerline of the impeller. On the air outlet side of the trailing edge 101 of the blades 10, the serrated structure 20 can suppress laminar boundary layer splitting at the trailing edge 101 of the blades 10, reduce the intensity of the separated vortices, and thus achieve the purpose of fan noise reduction. In addition, the serrated structure 20 of the trailing edge 101 of the blades 10 can also transform concentrated vortex shedding into discrete vortex shedding, and reduce the size of the shed vortices, thereby optimizing the flow and avoiding noise generation, achieving the purpose of noise reduction and frequency modulation.
[0074] The foregoing description and accompanying drawings fully illustrate embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included or substituted for parts and features of other embodiments. Embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from its scope. The scope of the present disclosure is limited only by the appended claims.
Claims
1. An impeller, characterized by, Comprising: a blade, a trailing edge of the blade being provided with a sawtooth structure; wherein part or all of the sawtooth structure is configured to extend inwardly from the trailing edge of the blade; the sawtooth structure comprising: an outward extension portion configured to extend outwardly from the trailing edge of the blade; an inward cut portion integrally formed with the outward extension portion and configured to extend inwardly from the trailing edge of the blade; wherein a height of the outward extension portion is greater than or equal to a height of the inward cut portion.
2. The impeller according to claim 1, wherein: a height ratio of the outward extension portion to a tooth height of the sawtooth structure is 0.5-0.
7.
3. The impeller according to claim 1, wherein: a tooth top portion of the sawtooth structure is in a sharp corner structure.
4. The impeller according to claim 1, wherein: a tooth root portion of the sawtooth structure is in an arc structure.
5. The impeller according to claim 1, wherein: the blade is in an arc shape, and a normal of a corresponding point of the blade and the sawtooth structure is provided with a preset included angle.
6. The impeller according to claim 1, wherein: a tooth height dimension of the sawtooth structure is less than or equal to a tooth width dimension.
7. The impeller of any one of claims 1 to 6, wherein, Further comprising: a support sheet, the support sheet being located at both ends of the impeller and being in a ring structure; wherein a plurality of blades are arranged around the support sheet.
8. A centrifugal fan characterized by Comprising the impeller according to any one of claims 1-7.
9. An air conditioning device characterized by comprising: Comprising the centrifugal fan according to claim 8.