Centrifugal fan impeller, centrifugal fan and bionic winglet design method

Abstract

The application discloses a centrifugal fan impeller, a centrifugal fan and a bionic winglet design method, which comprises an impeller body and a blade end winglet, a plurality of blade end winglets are fixedly arranged at one end of the impeller body and are arranged into a circular ring along the circumference of the impeller body; the blade end winglets are gradually increased or decreased along the axial length of the impeller body in sequence along the circumference of the impeller body to form a wave-shaped structure; on the one hand, the bionic wave-shaped distributed blade end winglet structure can straighten the airflow, inhibit the generation and development of vortexes and further reduce vortex noise; on the other hand, the blade end winglet structure with different length distribution characteristics can break the periodic frequency characteristics of the noise source, inhibit the noise peak and effectively inhibit harmonic vibration noise; on the third hand, the blade end winglet can further work on the low-speed and low-pressure airflow, inhibit the gas backflow leakage and the airflow hindering effect at the inlet, and further increase the outlet air pressure and air volume of the fan.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan technology, specifically to a centrifugal fan impeller, a centrifugal fan, and a biomimetic winglet design method. Background Technology

[0002] Multi-blade centrifugal fans are characterized by their compact structure, high pressure coefficient, and large flow coefficient. Therefore, they are widely used in household appliances such as air conditioners and range hoods. With the vigorous promotion of energy conservation and emission reduction, there are increasingly higher requirements for the air volume and air pressure of multi-blade centrifugal fans.

[0003] As the main working component of a multi-blade centrifugal fan, the performance of the impeller determines the fan's air volume, air pressure, and noise level. When the multi-blade centrifugal fan is running, the uneven pressure distribution in the cavity formed between the front and rear discs of the impeller and the collector volute can easily generate vortices, which can induce vortex noise. Furthermore, the high-pressure airflow inside the volute can leak back through the cavity to the fan inlet, obstructing the airflow at the fan inlet and thus reducing the fan's air volume and air pressure.

[0004] Therefore, improving the airflow within the cavity and reducing internal vortices and high-pressure air leakage and backflow, while increasing the fan's air volume and pressure, is one of the main tasks in the design of multi-blade centrifugal fan impeller structures. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a design method for a centrifugal fan impeller, a centrifugal fan, and a biomimetic winglet. This invention solves the technical problems in the prior art where uneven pressure distribution in the cavity formed between the front and rear discs of the impeller and the collector volute easily generates vortices, which in turn induces vortex noise. Furthermore, the high-pressure airflow in the volute will leak back through the cavity to the fan inlet, hindering the airflow at the fan inlet and thus reducing the fan's air volume and air pressure.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: This invention provides a centrifugal fan with biomimetic winglets, including an impeller body and blade tip winglets. The impeller body is a cylindrical structure. A plurality of blade tip winglets are fixedly disposed at one end of the impeller body and arranged in a ring along the circumference of the impeller body. The length of each blade tip winglet along the axial direction of the impeller body increases or decreases sequentially to form a wave-shaped structure.

[0007] In some embodiments, the impeller body includes a plurality of annular disks and a plurality of blades. The annular disks are coaxially spaced apart, and the blades are fixedly connected to the annular disks. The blades are parallel to the axial direction of the annular disks and are evenly spaced along the circumference of the annular disks. Each blade tip winglet is fixedly disposed on the annular disk at one end of the impeller body.

[0008] In some embodiments, the inner profile of each blade tip winglet corresponds one-to-one with each blade, and the blade tip winglet is located at the end of the blade.

[0009] In some embodiments, both the blade and the blade tip winglet have a circular arc-shaped forward bending feature.

[0010] In some embodiments, the inlet end of the blade is provided with a chamfer.

[0011] A centrifugal fan, in some embodiments, includes a centrifugal fan impeller and a housing. The housing includes a volute and a collector. The collector is installed at the air inlet end of the volute. The impeller body is coaxial with the volute and rotatably connected inside the volute. A cavity is formed between the annular disk near the collector and the collector. One end of each blade tip wingtip is fixedly connected to the annular disk inside the cavity and is evenly spaced along the circumference of the annular disk. The other end of each blade tip wingtip is suspended in the cavity and forms a wave-like structure along the circumference of the annular disk.

[0012] A design method for a biomimetic winglet, in some embodiments for designing the biomimetic winglet of the centrifugal fan, includes the following steps: Step 1: Extract the structure of the wavy leading edge of the humpback whale's flipper, correct and construct the curve of the wavy leading edge structure; Step 2: Extract feature points of the wavy leading edge structure curve ( , Based on the characteristic points of the wavy leading edge curve ( , The control equations of the curve are fitted to obtain the fitting curve of the biomimetic wave-shaped leading edge; Step 3: The fitted curve of the biomimetic wavy leading edge and the wavy leading edge structure curve maintain a high degree of consistency in structure. The equation corresponding to the fitted curve is: ,in λ The wavelength of the fitted curve, A The amplitude of the fitted curve, x This refers to the nth blade of the impeller body. y ( x ) is the first x The amplitude height of the blade tip winglet corresponding to each blade y ; Step 4: Based on the fact that the outer profile of the blade tip winglet is the same as the shape of the collector profile of the collector, the rectifying side width of the blade tip winglet is obtained. e Width of the outer profile of the collector f Equal to the outer profile width of the collector f This can be obtained by measuring with tools. e Therefore, the width of the blade tip winglet is obtained as follows: y + e ; Step 5: Height of the chamfer h =(0.2~0.4) R 2. The height g of the blade tip winglet = L - h ,in, L The blade height; Step 6: Obtain the different amplitude heights of the blade tip winglets on each blade by combining the fitted curves. y This results in the overall periodic wave-like distribution of each of the blade tip winglets.

[0013] In some embodiments, the amplitude of the fitted curve A The mathematical model is as follows: , λ λ is the wavelength of the fitted curve.

[0014] In some embodiments, the wavelength of the fitted curve The mathematical model is as follows: ,in, R 1 represents the radius of the impeller body. n The total number of blades in the impeller body. m To be in periodic wavelength λ The number of blades mentioned below, m =6~8.

[0015] In some embodiments, the width of the cavity is the distance from the collector to the annular disk. d ,and d =(0.4~0.6) R 2, d > y + e .

[0016] Compared with existing technologies, the present invention provides a centrifugal fan impeller, centrifugal fan, and biomimetic winglet design method. On the one hand, the biomimetic wave-shaped winglet structure can rectify the airflow, suppress the generation and development of vortices, and thus reduce vortex noise. On the other hand, the winglet structure with different length distribution characteristics can break the periodic frequency characteristics of the noise source, suppress noise peaks, and effectively suppress harmonic vibration noise. On the third hand, the winglets can further perform work on low-speed, low-pressure airflow, suppress gas backflow leakage and airflow obstruction effects at the inlet and outlet, thereby increasing the outlet air pressure and air volume of the fan. Attached Figure Description

[0017] Figure 1 It is the flipper-like limb of the humpback whale and its wavy leading edge structure; Figure 2 It is the establishment of the modified wavy leading edge structure of the flippers; Figure 3 It is a fitted curve of a biomimetic wave-shaped leading edge; Figure 4 These are the structural parameters of a blade with tip winglets; Figure 5 It is a three-dimensional image of a blade with winglets at the tip; Figure 6 yes Figure 5 Front view; Figure 7 This is a schematic diagram of a blade with winglets mounted on a ring disk. Figure 8 This is a schematic diagram of the structure where the blade tip winglets are mounted on the ring disk; Figure 9 It is a comparison between the impeller body and a conventional impeller; Figure 10 This is a structural schematic diagram of the impeller body and the outer casing; Figure 11 It is a cross-sectional view of the impeller body and the outer casing; Figure 12 yes Figure 11 A magnified view of part A in the middle; Figure 13 Yes, yes Figure 11 A magnified view of part B in the middle; Figure 14 It is a comparison between the cavity formed by the impeller body and the cavity formed by a conventional impeller.

[0018] Figure reference numerals: 1. Impeller body; 11. Annular disk; 12. Blade; 121. Chamfer; 122. Blade profile; 2. Blade tip winglet; 21. Inner winglet profile; 22. Outer winglet profile; 3. Outer shell; 31. Volute; 32. Collector; 321. Collector profile; 33. Cavity; 4. Humpback whale flipper structure; 5. Bionic wave-shaped leading edge structure of the flipper; 6. Bionic wave-shaped leading edge fitting curve; 7. Conventional impeller; 71. Cavity formed by a conventional impeller. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the invention and are not intended to limit the invention.

[0020] To address the technical problems of uneven pressure distribution within the cavity formed between the front and rear discs of the impeller and the collector volute, which easily generates vortices and induces eddy noise, and where high-pressure airflow within the volute leaks back through the cavity to the fan inlet, obstructing airflow and reducing fan volume and pressure, this invention provides a centrifugal fan impeller, centrifugal fan, and biomimetic winglet design method. This method can suppress the generation and development of vortices within the cavity, suppress harmonic vibration noise of the impeller, and suppress gas backflow leakage and airflow obstruction effects at the inlet.

[0021] It should be noted that the centrifugal fan impeller, centrifugal fan, and biomimetic winglet design method described in this invention are applicable to, but not limited to, multi-blade centrifugal fans. For ease of explanation, this invention only uses the application of the centrifugal fan impeller, centrifugal fan, and biomimetic winglet design method to a multi-blade centrifugal fan as an example. The principle of applying the centrifugal fan impeller, centrifugal fan, and biomimetic winglet design method to other types of equipment is essentially the same as the principle applied to multi-blade centrifugal fans, and will not be elaborated here.

[0022] Please see Figures 1 to 14 ,in Figure 10 This is a schematic diagram of a centrifugal fan with biomimetic winglets according to an embodiment of the present invention. The centrifugal fan with biomimetic winglets includes an impeller body 1 and blade tip winglets 2. The impeller body 1 is a cylindrical structure. Multiple blade tip winglets 2 are fixedly disposed at one end of the impeller body 1 and arranged in a ring along the circumference of the impeller body 1. Along the circumference of the impeller body 1, the length of each blade tip winglet 2 along the axial length of the impeller body 1 increases or decreases sequentially to form a wave-shaped structure.

[0023] In this embodiment, firstly, the biomimetic wave-shaped blade tip wing 2 structure can rectify the airflow, suppress the generation and development of vortices, and thus reduce vortex noise; secondly, the blade tip wing 2 structure with different length distribution characteristics can break the periodic frequency characteristics of the noise source, suppress noise peaks, and effectively suppress harmonic vibration noise; thirdly, the blade tip wing 2 can further perform work on low-speed, low-pressure airflow, suppress gas backflow leakage and airflow obstruction effects at the inlet and outlet, and thus increase the outlet air pressure and air volume of the fan.

[0024] In one embodiment, the impeller body 1 includes a plurality of ring disks 11 and a plurality of blades 12. The ring disks 11 are coaxially spaced apart, and the blades 12 are fixedly connected to the ring disks 11. The blades 12 are parallel to the axial direction of the ring disks 11 and are equally spaced along the circumference of the ring disks 11. The blade tip winglets 2 are fixedly disposed on the ring disks 11 at one end of the impeller body 1.

[0025] Furthermore, the multiple annular disks 11 preferably adopt three annular disks 11, including a front disk, a middle disk, and a rear disk. The blade tip winglets 2 are distributed at the front disk position and the rear disk position of the blade, and are connected to the front end and rear end of the blade 12 respectively, serving as the front blade winglet and the rear blade winglet. The addition of blade tip winglets 2 to the end of the conventional impeller can effectively utilize the stagnation cavity 33 formed between the front or rear disk of the impeller body 1 and the walls of the volute 31 and the collector 32 to further perform work on the airflow, increasing the fan's air volume and air pressure; at the same time, the cavity 33 is a low-pressure area, and the blade tip winglet 2 structure can block The high-pressure airflow in the volute 31 leaks back into the cavity 33, reducing the generation and development of vortices in the cavity 33, weakening the obstruction effect of the leaked airflow on the inlet of the blade 12, and thus reducing the vortex noise and impeller inlet interference noise generated in the cavity 33. The blade tip winglet 2 structure with biomimetic wave-shaped width distribution can break the single-tone noise and discrete broadband noise generated by the periodic interference of airflow between the rotating blade 12 and the fixed volute 31 and collector 32. At the same time, this wave-shaped variation feature can reduce the local sound pressure peak at a specific frequency in the noise spectrum, thereby suppressing resonance noise.

[0026] In one embodiment, please refer to Figure 5 , Figure 6 and Figure 7 Each blade tip winglet 2 has an inner winglet profile 21 corresponding to each blade 12, and the blade tip winglet 2 is located at the end of the blade 12.

[0027] In one embodiment, please refer to Figure 5 Both the blade 12 and the leaflet 2 have a circular arc-shaped forward curvature.

[0028] In one embodiment, please refer to Figure 5 , Figure 6 and Figure 7 The inlet end of the blade 12 is provided with a chamfer 121. Due to the influence of the wall at the outlet of the collector 32, in order to allow the airflow to enter the impeller body 1 more smoothly to do work and reduce airflow disturbance, the inlet end of the blade 12 is provided with a blade chamfer 121 structure.

[0029] A centrifugal fan, in one embodiment, includes a centrifugal fan impeller and a housing 3. The housing 3 includes a volute 31 and a collector 32. The collector 32 is installed at the air inlet end of the volute 31. The impeller body 1 is coaxial with the volute 31 and rotatably connected inside the volute 31. A cavity 33 is formed between the annular disk 11 near the collector 32 and the collector 32. One end of each blade tip wing 2 is fixedly connected to the annular disk 11 inside the cavity 33 and is evenly distributed along the circumference of the annular disk 11. The other end of each blade tip wing 2 is suspended in the cavity 33 and forms a wave-shaped structure along the circumference of the annular disk 11.

[0030] Furthermore, please refer to Figure 7 The connection position between the blade tip winglet 2 and the ring disk 11 has an inner winglet profile 21, and the connection position between the blade 12 and the ring disk 11 has a blade profile 122. The inner winglet profile 21 and the blade profile 122 have the same curvature. The axial structure of the blade tip winglet 2 is controlled by the blade profile 122, while the radial structural features are controlled by the outer winglet profile 22 of the blade tip winglet 2.

[0031] Furthermore, please refer to Figure 4 , Figure 12 and Figure 13 The winglet 2 has an outer winglet profile 22 at one end, and the inner wall of the collector 32 has a collector profile 321. The outer winglet profile 22 and the collector profile 321 have the same structural dimensions, which better achieves the rectification of the airflow state in the cavity 33. The rectification side structure of the winglet 2 has a curved structure feature, that is, the radius of the collector 32 is... R 2 is 0.08-0.12 times the impeller body; 1 is the impeller radius. R 1, R 2 = (0.08~0.12) R 1. Collector 32 side tilt angle θ =10°~15°.

[0032] For a design method of a biomimetic winglet, please refer to [link / reference]. Figure 3 , Figure 4 , Figure 6 , Figure 8 , Figure 9 and Figure 12 The design of biomimetic winglets includes the following steps: Step 1: Extract the structure of the wavy leading edge of the humpback whale's flipper, correct and construct the curve of the wavy leading edge structure; Step 2: Extract feature points of the wavy leading edge structure curve ( , Based on the characteristic points of the wavy leading edge curve ( , The control equations of the curve are fitted to obtain the fitting curve of the biomimetic wave-shaped leading edge; Step 3: The fitted curve of the biomimetic wavy leading edge and the wavy leading edge structure curve maintain a high degree of consistency in structure. The equation corresponding to the fitted curve is: ,in λ The wavelength of the fitted curve, A The amplitude of the fitted curve, x Which blade 12 is in the impeller body 1? y ( x ) is the first x The amplitude height of the blade tip winglet 2 corresponding to each blade 12 y ; Step 4: Based on the fact that the outer profile 22 of the blade tip winglet 2 and the collector profile 321 of the collector 32 have the same shape, the rectifying side width of the blade tip winglet 2 is obtained. e Width of the outer profile of collector 32 f Equal to the outer profile width of collector 32 f This can be obtained by measuring with tools. e Therefore, the width of the blade tip winglet 2 is obtained as follows: y + e ; Step 5: Height of chamfer 121 h =(0.2~0.4) R 2. The height of the winglet 2, g = L - h ,in, L The blade height is 12. Step 6: Obtain the different amplitude heights of the blade tip winglets 2 on each blade 12 by combining the fitted curves. y This results in the overall periodic wave-like distribution of each blade tip winglet 2.

[0033] Furthermore, since the outer profile 22 of the winglet maintains the same structural dimensions as the collector profile 321, the rectifying side width of the blade tip winglet 2 is... e Width of the outer profile of collector 32 f Equal to the outer profile width of collector 32 f The shape of the collector profile 321 is determined by the radius of the collector 32. R 2 and the tilt angle of collector 32 θ The determination is based on the radius of collector 32. R 2 = (0.08~0.12) R 1, among which, R 1 represents the radius of the impeller body 1, and the side inclination angle of the collector 32 is... θ =10°~15°.

[0034] It's important to understand that humpback whales belong to the order Cetacea, family Baleen whales, and are among the largest marine animals. Most of their bodies are inflexible, limiting their maneuverability. However, humpback whales have longer and more flexible flippers than most whales, with unique wavy protrusions at their leading edges. They utilize these extremely flexible, high-to-width ratio flippers for gliding and turning. Biologists believe that this unique, continuous wavy protrusion structure facilitates the humpback whale's agile and explosive swimming movements. Figure 1 The large, continuous, wavy protrusions along the leading edge of the flippers are a unique morphological structure of this animal. The position, size, and number of the protrusions on the flippers indicate that this structure can greatly improve the hydrodynamic properties of the humpback whale's surface and surroundings, reducing drag and noise during swimming. Since the fluid velocity around the humpback whale's flipper is 3-8 m / s, and the airflow velocity at the inlet of the multi-blade centrifugal fan is on the same order of magnitude, and the continuous wave-like structure has the functions of stabilizing the flow state near the wall, disrupting the generation and development of the boundary layer during the turbulence process, and reducing the size and number of vortices in the flow channel, the continuous wave-like structure of the humpback whale's flipper was chosen as the biomimetic object. Combined with the characteristics of the cavity 33 formed at the junction of the collector 32, volute 31, and the front / rear annular disk 11 of the blades 12 in the multi-blade centrifugal fan—intense airflow fluctuations, severe flow separation vortices, large high-pressure fluid leakage, and significant vortex noise—this approach aims to suppress airflow fluctuations and leakage, as well as vortex generation, within the cavity 33 at the junction of the collector 32, volute 31, and blades 12, thereby reducing the fan's vortex noise and improving its aerodynamic performance. Figure 2 To establish the biomimetic wave-shaped leading edge structure based on the original fin-like limb reconstruction, this continuous wave-shaped leading edge feature is fitted and reconstructed to obtain the biomimetic continuous wave-shaped leading edge curve and its curve equation. This biomimetic wave-shaped curve feature is used to establish the distribution characteristics of the blade tip winglet 2 structure height in the front and rear disk regions of the impeller body 1, thus obtaining the biomimetic blade tip winglet 2 structure with continuous wave variation characteristics.

[0035] Furthermore, for a single-suction impeller body 1, there is only one cavity 33, and the blade tip wing 2 exists only on one side; for a double-suction impeller body 1, there are two cavities 33 on both sides, and consequently, the blade tip wing 2 also exists on both sides. The blade tip wing 2 at both ends of the same blade 12 has the same structure. If the width of the cavities 33 on both sides of the double-suction impeller body 1 is... dIf they are the same, then the width of the two blade tip winglets 2 is... y + e Same; if the width of the two side cavities 33 of the double-suction impeller body 1 is the same. d If they are different, then the amplitude height of the two blade tip winglets 2 is... y They are different, for a cavity width of 33. d On the larger side, the amplitude A = 0.06 λ For a cavity width of 33 d On the smaller side, the amplitude A = 0.04 λ .

[0036] In one embodiment, please refer to Figure 3 The amplitude of the fitted curve A The mathematical model is as follows: , λ λ is the wavelength of the fitted curve.

[0037] In one embodiment, please refer to Figure 9 The wavelength of the fitted curve The mathematical model is as follows: ,in, R 1 represents the radius of the impeller body 1. n The total number of blades 12 in impeller body 1. m To be in periodic wavelength λ The number of leaves below 12 m =6~8.

[0038] Furthermore, This is the fitting equation for fin-like, wavy leading-edge structures of different sizes, where the curve wavelength... The amplitude A of the curve controls the dimensional differences of biomimetic wave-shaped leading edge structures of different sizes. To apply this biomimetic fitting curve to a centrifugal fan, the curve wavelength is set. The amplitude A of the curve is the impeller radius. R 1. Relevant parameters, , That is, the wavelength of the curve. The parametric equations for the amplitude A of the curve.

[0039] In one embodiment, please refer to Figure 12 The width of cavity 33 is the distance from collector 32 to ring disk 11. d ,and d =(0.4~0.6) R 2, d > y + e That is, the width of cavity 33 needs to be greater than the width of blade tip winglet 2, and the amplitude of blade tip winglet 2... yThe size is controlled by the biomimetic wave leading edge curve, and the width of different blade tip winglets 2 varies periodically according to the characteristics of the biomimetic wave-shaped leading edge curve.

[0040] To better understand this invention, the following is combined with... Figures 1 to 14 The technical solution of the present invention will be described in detail below: Step 1: Extract the structure of the wavy leading edge of the humpback whale's flipper, correct and construct the curve of the wavy leading edge structure; Step 2: Extract feature points of the wavy leading edge structure curve ( , Based on the characteristic points of the wavy leading edge curve ( , The control equations of the curve are fitted to obtain the fitting curve of the biomimetic wave-shaped leading edge; Step 3: The fitted curve of the biomimetic wavy leading edge and the wavy leading edge structure curve maintain a high degree of consistency in structure. The equation corresponding to the fitted curve is: ,in λ The wavelength of the fitted curve, A The amplitude of the fitted curve, x Which blade 12 is in the impeller body 1? y ( x ) is the first x The amplitude height of the blade tip winglet 2 corresponding to each blade 12 y ; Step 4: Utilize , Therefore, we can conclude that: Therefore, the first x The amplitude height of the blade tip winglet 2 corresponding to each blade 12 y ; Step 5: Rectifying side width of blade tip winglet 2 e Width of the outer profile of collector 32 f Equal to the outer profile width of collector 32 f This can be obtained by measuring with tools. e Therefore, the width of the blade tip winglet 2 is obtained as follows: y + e ; Step 6: Height of chamfer 121 h =(0.2~0.4) R 2. The height of the winglet 2, g = L - h ,in, L The blade height is 12. Step 7: Obtain the different amplitude heights of the blade tip winglets 2 on each blade 12 by combining the fitted curves. yThis results in the overall periodic wave-like distribution of each blade tip winglet 2. In a conventional impeller, a cavity 33 is formed between the annular disk 11 at both ends and the walls of the volute 31 and collector 32. Boundary layer separation is very likely to occur in the cavity 33, forming a large number of vortices, which in turn generate vortex noise. At the same time, there is no structure to do work in the cavity 33 of the conventional impeller, which is in a low-pressure area. The high-pressure airflow in the volute 31 can easily flow to the inlet of the blade 12 through this area, causing gas leakage and interfering with the airflow at the impeller inlet, thereby reducing the aerodynamic performance of the fan. The addition of biomimetic wave-shaped blade tip winglets 2 within the cavity 33 can rectify the airflow within the cavity 33, suppressing the generation and development of vortices within the cavity 33, thereby reducing vortex noise within the cavity 33. The blade tip winglets 2 structures with different length distribution characteristics can break the periodic frequency characteristics of the noise source, suppress noise peaks, and effectively suppress harmonic vibration noise of the impeller. At the same time, the addition of blade tip winglets 2 within the cavity 33 can further perform work on the low-speed, low-pressure airflow within the cavity 33, suppressing gas backflow leakage at the cavity 33 and the airflow obstruction effect at the inlet and outlet, thereby increasing the outlet air pressure and air volume of the fan.

[0041] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A centrifugal fan impeller, characterized in that, include: The impeller body is a cylindrical structure; The blade tip winglets are fixedly disposed at one end of the impeller body and arranged in a ring along the circumference of the impeller body. The blade tip winglets increase or decrease in length along the circumference of the impeller body and along the axial length of the impeller body to form a wave-shaped structure.

2. The centrifugal fan impeller according to claim 1, characterized in that, The impeller body includes multiple ring disks and multiple blades. The ring disks are coaxially spaced apart. Each blade is fixedly connected to each ring disk. Each blade is parallel to the axial direction of the ring disk and is evenly distributed along the circumference of the ring disk. Each blade tip winglet is fixedly disposed on the ring disk at one end of the impeller body.

3. The centrifugal fan impeller according to claim 2, characterized in that, Each blade tip winglet has an inner winglet profile that corresponds to each blade, and the blade tip winglet is located at the end of the blade.

4. The centrifugal fan impeller according to claim 2, characterized in that, Both the blade and the blade tip winglet have a circular arc-shaped forward curvature feature.

5. The centrifugal fan impeller according to claim 2, characterized in that, The inlet end of the blade is provided with a chamfer.

6. A centrifugal fan, characterized in that, It includes a centrifugal fan impeller as described in any one of claims 1-5, and a housing, the housing including a volute and a collector, the collector being installed at the air inlet end of the volute, the impeller body being coaxial with the volute and rotatably connected inside the volute, a cavity being formed between the annular disk near the collector and the collector, one end of each blade tip winglet being fixedly connected to the annular disk inside the cavity and evenly spaced along the circumference of the annular disk, and the other end of each blade tip winglet being suspended in the cavity and forming a wave-like structure along the circumference of the annular disk.

7. A design method for a biomimetic winglet, characterized in that, The process for designing the biomimetic winglet of the centrifugal fan of claim 6 includes the following steps: Step 1: Extract the structure of the wavy leading edge of the humpback whale's flipper, correct and construct the curve of the wavy leading edge structure; Step 2: Extract feature points of the wavy leading edge structure curve ( , Based on the characteristic points of the wavy leading edge curve ( , The governing equations of the curve are fitted to obtain the fitted curve of the biomimetic wave-shaped leading edge; Step 3: The fitted curve of the biomimetic wavy leading edge and the wavy leading edge structure curve maintain a high degree of consistency in structure. The equation corresponding to the fitted curve is: ,in λ The wavelength of the fitted curve, A The amplitude of the fitted curve, x This refers to the nth blade of the impeller body. y ( x ) is the first x The amplitude height of the blade tip winglet corresponding to each blade y ; Step 4: Based on the fact that the outer profile of the blade tip winglet is the same as the shape of the collector profile of the collector, the rectifying side width of the blade tip winglet is obtained. e Width of the outer profile of the collector f Equal to, further, the outer profile width of the collector f This can be obtained by measuring with tools. e Therefore, the width of the blade tip winglet is obtained as follows: y + e ; Step 5: Height of the chamfer h =(0.2~0.4) R 2. The height g of the blade tip winglet = L - h ,in, L The blade height; Step 6: Obtain the different amplitude heights of the blade tip winglets on each blade by combining the fitted curves. y This results in the overall periodic wave-like distribution of each of the blade tip winglets.

8. The design method of the biomimetic winglet according to claim 7, characterized in that, The amplitude of the fitted curve A The mathematical model is as follows: , λ λ is the wavelength of the fitted curve.

9. The design method of a biomimetic winglet according to claim 8, characterized in that, The wavelength of the fitted curve The mathematical model is as follows: ,in, R 1 represents the radius of the impeller body. n The total number of blades in the impeller body. m To be in periodic wavelength λ The number of blades mentioned below, m =6~8.

10. The design method of the biomimetic winglet according to claim 7, characterized in that, The width of the cavity is the distance from the collector to the annular disk. d ,and d =(0.4~0.6) R 2, d > y + e .

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