Blade, axial flow fan and air supply equipment

Abstract

The application provides a blade, an axial flow fan and an air supply equipment, and belongs to the technical field of air supply equipment. The blade is characterized in that a first groove is arranged on the windward surface of the blade body, the first front groove wall, the first inner groove wall, the first tail groove wall and the first outer groove wall of the first groove correspond to the layout of the leading edge side wall, the inner edge side wall, the trailing edge side wall and the outer edge side wall near the blade body respectively, the material in the area with low stress of the blade can be reasonably removed, the overall quality of the blade is effectively reduced, the operation efficiency of the blade is improved, the stress concentration problem of the blade is avoided, the strength and operation reliability of the blade are enhanced, the service life of the blade is prolonged, and the dual requirements of light weight and structural stability are met.

Description

Technical Field

[0001] This application relates to the field of air supply equipment technology, and more specifically, to a blade, an axial flow fan, and an air supply device. Background Technology

[0002] As the core component of the wind turbine system, the structural strength of the blades is directly related to the safety and service life of the equipment.

[0003] During rotation, the blade is mainly subjected to the interaction of centrifugal force and aerodynamic load, resulting in stress concentration at the blade root. This continuous stress concentration can easily lead to fatigue cracks at the blade root, eventually causing structural cracking or even breakage at the blade root. This directly affects the structural integrity and operational reliability of the blade, and may even lead to blade breakage or induce sudden equipment failure, posing a serious threat to overall safety.

[0004] Current methods for optimizing blade strength include increasing material thickness, homogenizing the structure, or adding reinforcing ribs. Summary of the Invention

[0005] This application provides a blade, an axial flow fan, and an air supply device. The blade features a first groove on its windward side. The first front groove wall, first inner groove wall, first tail groove wall, and first outer groove wall are arranged to correspond to the leading edge sidewall, inner edge sidewall, tail edge sidewall, and outer edge sidewall of the blade body, respectively. This arrangement allows for efficient material removal in areas of low blade stress, effectively reducing the overall blade mass, improving blade operating efficiency, preventing stress concentration, enhancing blade strength and operational reliability, and extending blade lifespan, thus balancing the dual requirements of lightweight design and structural stability. Specifically: The first aspect of this application provides a blade, comprising: The blade body includes a windward side and a leeward side arranged opposite to each other, and a leading edge sidewall, an inner edge sidewall, a trailing edge sidewall and an outer edge sidewall formed on the outer periphery of the windward side and the leeward sidewall and connected end to end. A first groove is provided on the windward side of the blade body. The first groove includes a first front groove wall, a first inner groove wall, a first tail groove wall, and a first outer groove wall connected end to end. The first front groove wall is positioned corresponding to and close to the front edge side wall, the first inner groove wall is positioned corresponding to and close to the inner edge side wall, the first tail groove wall is positioned corresponding to and close to the tail edge side wall, and the first outer groove wall is positioned corresponding to and close to the outer edge side wall.

[0006] In the above technical solution, the first front side groove wall and the first outer side groove wall have a connection point A, the first outer side groove wall and the first tail side groove wall have a connection point B, and the first tail side groove wall and the first inner side groove wall have a connection point C. The minimum distance between point A and the leading edge sidewall is d1, the minimum distance between point A and the outer edge sidewall is d2, the minimum distance between point B and the trailing edge sidewall is d3, and the minimum distance between point C and the inner edge sidewall is d4. The relationships between d1, d2, d3, and d4 are as follows: d1 < d2 < d3 < d4.

[0007] In the above technical solutions, 30mm≤d1≤35mm; 35mm≤d2≤40mm; 50mm≤d3≤60mm; 60mm≤d4≤70mm.

[0008] In the above technical solution, the shape of the first groove is adapted to the shape of the blade body; and / or The connection points between adjacent groove walls in the first groove have rounded corners, and the radius r of the rounded corners satisfies: 1.5mm≤r≤2.5mm.

[0009] In the above technical solution, the area of ​​the blade body is S1, and the projected area of ​​the first groove on the blade body is S2, wherein the ratio k of S2 and S1 satisfies: 0.7≤k1≤0.75. And / or, The thickness of the blade body is H1, and the groove depth of the first groove is H2, where H2 = 15% * H1 ~ 25% * H1.

[0010] In the above technical solution, the windward side of the blade body is also provided with a second groove. The projected area S3 of the second groove on the blade body is smaller than the projected area S2 of the first groove on the blade body, and the second groove is opened between the first front side groove wall and the leading edge side wall.

[0011] In the above technical solution, the ratio k2 between S2 and S3 satisfies: 4.9≤k2≤5.3.

[0012] In the above technical solution, the groove depth of the first groove is H2, and the groove depth of the second groove is H3, wherein the ratio k3 between H2 and H3 satisfies: 0.56≤k3≤0.67.

[0013] In the above technical solution, the first front side groove wall and the first outer side groove wall have a connection point A, and the first front side groove wall and the first inner side groove wall have a connection point D. The second groove is positioned closer to point D than to points A and D.

[0014] In the above technical solution, the second groove is a rectangular groove, and the second groove includes a second front groove wall, a second inner groove wall, a second tail groove wall and a second outer groove wall connected end to end. The second front side groove wall is located on one long side of the second groove and is close to the front edge side wall. The second tail side groove wall is located on the other long side of the second groove and is close to the first front side groove wall.

[0015] In the above technical solution, one end of the second tail side groove wall is located at point D and the other end extends towards point A. The extension length of the second tail side groove wall is L2, and the extension length of the first front side groove wall is L1. The ratio k4 between L2 and L1 satisfies: 0.19≤k4≤0.26.

[0016] In the above technical solution, a connector is also provided on the inner edge sidewall of the blade body for connecting the blade body to the blade hub, and a serrated structure is also provided on the trailing edge sidewall of the blade body.

[0017] A second aspect of this application provides an axial flow fan that uses the blades described above.

[0018] A third aspect of this application provides an air supply device, which includes the axial flow fan described above.

[0019] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: In this embodiment, the blade has a first groove on the windward side of the blade body. The first front groove wall, the first inner groove wall, the first tail groove wall, and the first outer groove wall are arranged to correspond to the leading edge sidewall, the inner edge sidewall, the tail edge sidewall, and the outer edge sidewall of the blade body, respectively. This arrangement allows for the reasonable removal of material in areas of low blade stress, effectively reducing the overall weight of the blade, improving blade operating efficiency, avoiding stress concentration problems, enhancing blade strength and operational reliability, extending blade service life, and balancing the dual requirements of lightweighting and structural stability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the blade structure in the prior art; Figure 2 This is a schematic diagram of the structure of a wind turbine in the existing technology; Figure 3 Stress cloud diagram of existing technology wind turbine at 1900 rpm; Figure 4 This is a schematic diagram of the optimized blade in the embodiments of this application; Figure 5 This is a schematic diagram of the optimized fan structure in the embodiments of this application; Figure 6This is a stress cloud diagram of the optimized fan at 1900 rpm in the embodiments of this application.

[0021] in: 10-Blade body; 101-Leading edge sidewall; 102-Inner edge sidewall; 103-Tail edge sidewall; 104-Outer edge sidewall; 20 - First groove; 201 - First front groove wall; 202 - First inner groove wall; 203 - First tail groove wall; 204 - First outer groove wall; 30 - Second groove; 301 - Second front groove wall; 302 - Second inner groove wall; 303 - Second tail groove wall; 304 - Second outer groove wall; 40 - Connector; 50-Serrated structure. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. “Multiple” generally includes at least two, but does not exclude the inclusion of at least one.

[0024] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0025] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0026] Example like Figures 4-6 As shown, a first aspect of this application provides a blade, comprising: The blade body 10 includes a windward side and a leeward side arranged opposite to each other, and a leading edge sidewall 101, an inner edge sidewall 102, a trailing edge sidewall 103 and an outer edge sidewall 104 formed on the outer periphery of the windward side and the leeward side and connected end to end. A first groove 20 is provided on the windward side of the blade body 10. The first groove 20 includes a first front groove wall 201, a first inner groove wall 202, a first tail groove wall 203, and a first outer groove wall 204 connected end to end. The first front groove wall 201 is positioned corresponding to and close to the front edge side wall 101, the first inner groove wall 202 is positioned corresponding to and close to the inner edge side wall 102, the first tail groove wall 203 is positioned corresponding to and close to the tail edge side wall 103, and the first outer groove wall 204 is positioned corresponding to and close to the outer edge side wall 104.

[0027] In this embodiment, the blade has a first groove 20 on the windward side of the blade body 10. The arrangement of the first front groove wall 201, the first inner groove wall 202, the first tail groove wall 203, and the first outer groove wall 204 of the first groove 20, which are respectively close to the leading edge side wall 101, the inner edge side wall 102, the tail edge side wall 103, and the outer edge side wall 104 of the blade body 10, allows for reasonable removal of material in areas with low blade stress. This effectively reduces the overall weight of the blade, improves the blade's operating efficiency, avoids stress concentration problems, enhances blade strength and operational reliability, extends blade service life, and balances the dual requirements of lightweighting and structural stability.

[0028] Specifically, in the design of the blade in this application, the stress of the blade was first obtained through finite element simulation analysis. The stress value of the blade was much smaller than the yield strength limit of the material (as can be seen from the stress diagram, the dark blue and light blue areas on the windward side are both safe zones), resulting in redundant design. In order to save costs, the windward side of the blade was used as the design surface, the blade weight was used as the design target, and the volume and stress of the blade were used as boundary conditions. A mathematical model was built to optimize the blade. The optimized first groove 20 removes the material in the area with a small stress value on the windward side (safe zone), thereby improving the material utilization rate and reducing the weight of the blade. At the same time, the stress of the blade will be redistributed, the stress value at the root of the blade will be reduced, and the blade strength will be improved.

[0029] The design of the first groove 20 shape maximizes the amount of material that can be removed without affecting the strength and airflow effect, thus saving costs.

[0030] Specifically, the first front side groove wall 201 and the first outer side groove wall 204 have a connection point A, the first outer side groove wall 204 and the first tail side groove wall 203 have a connection point B, and the first tail side groove wall 203 and the first inner side groove wall 202 have a connection point C. The minimum distance between point A and the leading edge sidewall 101 is d1, the minimum distance between point A and the outer edge sidewall 104 is d2, the minimum distance between point B and the trailing edge sidewall 103 is d3, and the minimum distance between point C and the inner edge sidewall 102 is d4. The relationships between d1, d2, d3, and d4 are as follows: d1 < d2 < d3 < d4.

[0031] In this application, the qualitative relationship of d1 < d2 < d3 < d4 in the first groove maximizes the area of ​​material removed (weight reduction) without affecting blade strength and airflow performance. After the material is removed, the stress on the blade is redistributed, reducing the stress value at the blade root (high stress area). Specifically, by removing material from the low stress area, the stress value of the blade can be evenly distributed, the overall strength can be increased, and the stress in the high stress area can be reduced.

[0032] Preferably, 30mm≤d1≤35mm; 35mm≤d2≤40mm; 50mm≤d3≤60mm; 60mm≤d4≤70mm.

[0033] Further preferred values ​​are d1 (34 mm), d2 (36 mm), d3 (55 mm), and d4 (68 mm).

[0034] Furthermore, in some possible implementations, the shape of the first groove 20 is adapted to the shape of the blade body 10; and / or The connection points between adjacent groove walls in the first groove 20 have rounded corners, and the radius r of the rounded corners satisfies: 1.5mm≤r≤2.5mm, preferably, r is 2mm.

[0035] In this embodiment, by setting the shape of the first groove 20 to fit the shape of the blade body 10, the entire windward area of ​​the blade body 10 can be optimized as much as possible, thereby making the blade as lightweight as possible and saving costs. At the same time, rounding the corners of the connection points between adjacent groove walls can also avoid stress concentration.

[0036] Furthermore, in some possible implementations, the area of ​​the blade body 10 is S1, and the projected area of ​​the first groove 20 on the blade body 10 is S2, wherein the ratio k1 of S2 and S1 satisfies: 0.7≤k1≤0.75, that is, 0.7≤S2:S1≤0.75. And / or, The thickness of the blade body 10 is H1, and the groove depth of the first groove 20 is H2, where H2 = 15% * H1 ~ 25% * H1.

[0037] In this application, the ratio k1 of S2 is designed to satisfy 0.7≤k1≤0.75, which can ensure the lightweight of the blade while meeting the structural strength requirements of the blade, and at the same time reduce wind noise. Preferably, the value of k1 is 0.73.

[0038] In this application, the thickness H1 of the blade body 10 and the groove depth H2 of the first groove 20 are designed to satisfy: H2=15%*H1~25%*H1. This first groove depth design can first ensure the strength of the blade, secondly ensure the wind guiding effect of the blade, and reduce wind noise.

[0039] Furthermore, in some possible embodiments, the windward side of the blade body 10 is also provided with a second groove 30, the projected area S3 of the second groove 30 on the blade body 10 is smaller than the projected area S2 of the first groove 20 on the blade body 10, and the second groove 30 is opened between the first front side groove wall 201 and the leading edge side wall 101.

[0040] In this embodiment, two grooves, one large and one small, are provided on the windward side of the blade body 10, and the smaller second groove 30 is positioned between the first front side groove wall 201 and the leading edge side wall 101. This is because the smaller second groove 30 reduces the weight of the blade and also facilitates blade balancing. "It should be noted that blade balancing refers to the fact that when the blade rotates at high speed, uneven weight distribution can generate centrifugal force, causing strong vibrations that can lead to blade breakage." Preferably, the ratio k2 between S2 and S3 satisfies: 4.9≤k2≤5.3, that is, 4.9≤S2:S3≤5.3.

[0041] In this application, the ratio k2 between S2 and S3 is designed to satisfy: 4.9≤k2≤5.3, which can both ensure the strength of the blade and reduce wind noise.

[0042] Furthermore, the groove depth of the first groove 20 is H2, and the groove depth of the second groove 30 is H3, wherein the ratio k3 between H2 and H3 satisfies: 0.56≤k3≤0.67, that is, 0.56≤H2:H3≤0.67.

[0043] In this application, the ratio k3 between H2 and H3 is designed to satisfy: 0.56≤k3≤0.67. This ratio range is designed to ensure the blade strength while making the blade lightweight, and to prevent the risk of the blade cracking or even breaking during operation.

[0044] That is, the smaller second groove 30 is slightly deeper than the larger first groove 20.

[0045] Specifically, the maximum depth of the small groove (i.e., the second groove 30) is about 3mm, and the maximum depth of the large groove (i.e., the first groove 20) is about 2mm. This is to ensure that the overall strength of the blade meets the standard.

[0046] Furthermore, the first front side groove wall 201 and the first outer side groove wall 204 have a connection point A, and the first front side groove wall 201 and the first inner side groove wall 202 have a connection point D. The second groove 30 is positioned closer to point D than to points A and D.

[0047] The design of the second groove 30 in this application, which is close to point D, can ensure good airflow from the blades while delaying airflow diversion and improving the aesthetics of the blades.

[0048] Specifically, the second groove 30 is a rectangular groove, and the second groove 30 includes a second front groove wall 301, a second inner groove wall 302, a second tail groove wall 303, and a second outer groove wall 304 connected end to end. The second front side groove wall 301 is set as one long side of the second groove 30 and close to the front edge side wall 101, and the second tail side groove wall 303 is set as the other long side of the second groove 30 and close to the first front side groove wall 201.

[0049] More specifically, one end of the second tail side groove wall 303 is located at point D, and the other end extends towards point A. The extension length of the second tail side groove wall 303 is L2, and the extension length of the first front side groove wall 201 is L1. The ratio k4 between L2 and L1 satisfies: 0.19≤k4≤0.26, that is, 0.19≤L2:L1≤0.26.

[0050] In this application, the ratio k4 between L2 and L1 is designed to satisfy: 0.19≤k4≤0.26. This not only ensures the strength of the blade, but also improves the wind-guiding effect of the blade and reduces the wind noise of the blade.

[0051] Preferably, 204mm≤L1≤221mm, 43mm≤L2≤53mm.

[0052] like Figure 4 As shown, in this embodiment, the length of the second groove 30 is much smaller than the length of the first groove 20. It should be noted that if the smaller second groove 30 is enlarged, that is, if the long side of the smaller second groove 30 is extended to be the same length or approximately the same length as the first groove 20, although the mass of the blade is reduced, it will affect the air volume and structural rigidity of the blade.

[0053] Furthermore, in some possible embodiments, a connector 40 is provided at the inner edge sidewall 102 of the blade body 10 for connecting the blade body 10 to the blade hub, and a serrated structure 50 is provided at the trailing edge sidewall 103 of the blade body 10 to reduce wind noise.

[0054] In summary, the blade body 10 in this embodiment, through the above-described improvements, can effectively increase the strength of the blade body while reducing weight. Specifically, Figure 1 and Figure 2 The structure of the existing blade body and axial flow fan is shown. Figure 4 and Figure 5 The improved and optimized blade body and axial flow fan structure of the embodiments of this application are shown.

[0055] Simultaneously combined Figure 3 Stress diagram of the blade before improvement and Figure 6 As can be seen from the improved blade stress diagram, the blade body in this embodiment of the application, through the above-mentioned structural improvements, not only achieves a lightweight design of the blade body and effectively reduces production costs, but also effectively improves the structural strength of the blade body.

[0056] It should be noted that in the traditional blade design process, the assessment of the blade body strength mainly relies on simulation calculations to run the blade at two or three times the maximum speed for 5 to 10 minutes. The standard for checking whether the blade body fails or is damaged is whether the blade body strength meets the requirements. However, this method increases the design cost and is time-consuming and labor-intensive.

[0057] Based on this, the groove design on the blade in this embodiment is analyzed based on the dynamic stress simulation of the blade at a high speed of 1900 rpm, and the stress simulation results are extracted and the peak distribution area is determined. Then, the blade body is optimized according to the stress distribution of the blade body, and finally the blade body structure with the first groove 20 and the second groove 30 is obtained. The optimized blade body structure has a stress value reduced by 13.66% and a mass reduced by 19.12% at 1900 rpm, perfectly achieving the lightweight and high strength effect of the blade body.

[0058] Specifically, the design mainly includes the following steps: Step 1: First, obtain the 3D model of the wind turbine. Use a coarser mesh for the blade hub to save computation time, while use a finer mesh for the blade body to ensure the accuracy of the calculation results. The blade body material is PPS, with defined material properties: elastic modulus of 8.5 GPa, Poisson's ratio of 0.35, and density of 1.52 g / cm³.

[0059] Step Two: When the axial flow blade body rotates at high speed, it is mainly subjected to centrifugal force and aerodynamic load. The centrifugal force causes the blade body to stretch, while the aerodynamic load causes it to bend. Therefore, the two loads are in opposite directions. Since the bending stress generated by the aerodynamic load is negligible compared to the deformation generated by the centrifugal force during the high-speed rotation of the blade body, generally only the influence of the centrifugal force on the blade body is considered. Constraints are set on the blade according to the actual situation. Because the blade hub is generally fixed to the motor, the hub's three translational degrees of freedom are constrained, its circumferential rotational degree of freedom is released, and the remaining two rotational degrees of freedom are constrained. "Generally, there are three translational degrees of freedom and three rotational degrees of freedom, for a total of six degrees of freedom." A speed of 1900 rpm is applied to the hub to simulate the working state of the wind turbine during rotation.

[0060] Step 3: After the calculation is completed, the simulation results are extracted and the peak stress and stress distribution of the blade body are observed. According to the stress distribution, the stress value at the root of the blade body is the highest, reaching 102.09 MPa, while the stress value distribution on the surface of the blade body is relatively uniform. Therefore, structural optimization design is carried out on the windward side of the blade body with lower stress: In this embodiment, the goal is to minimize the compliance of the blade (minimum stress value), with element density as the design variable and volume fraction as the constraint condition for optimizing the blade body. The initial value is the state of the blade body before deformation, the lower limit is the minimum value that can be achieved by the positional changes of each variable of the blade body, and the upper limit is the maximum value that can be achieved by each variable of the blade body. The mathematical model for blade body optimization is shown in Formula 1 below:

[0061] In Formula 1 above, The element is the design variable for topology optimization; N is the number of elements that can be designed in the design region; The overall structural compliance of the optimized component is considered; minimizing compliance indicates maximizing static stiffness. It is a volume force; As the boundary area force, this patent mainly considers the centrifugal load experienced by the blade during rotation (the aerodynamic load has little effect on the blade). This represents the volume of the i-th unit; Indicates the overall structural volume of the component; Specify the percentage of quality to remove during optimization; This is the lower limit of density; The number of the non-design unit is indicated, and its pseudo density is always kept at 1; For stress tensor; Indicates and The corresponding virtual strain tensor; This represents a virtual displacement; Formula 2 below is the static equilibrium equation;

[0062] This patent uses a power interpolation model to correlate the artificial pseudo-density variable with the elastic modulus of the corresponding unit, as shown in Formula 3 below:

[0063] In formula three above, Let represent the elastic modulus of the i-th element; E represent the elastic modulus of the structural material; n represents the penalty factor, n=3; this patent uses gradient-based mathematical programming to solve the above mathematical model. The structural compliance with respect to the design variables can be calculated using the following formula:

[0064] In formula four above, This represents the displacement vector of the i-th element; Let i represent the element stiffness matrix of i elements. Calculate using Formula 5 below:

[0065] In Formula 5 above, B represents the element strain matrix; D represents the elastic modulus matrix.

[0066] The following formula is Formula Six:

[0067] In Formula 6 above, Let represent Poisson's ratio; according to Formula 6, Formula 4 above can be simplified to:

[0068] After determining the optimal design region of the blade, establishing the objective function and its constraints, and solving iteratively, the final optimized blade shape can be obtained.

[0069] Step 4: After the blade optimization design is completed, the stress simulation of the wind turbine at 1900 rpm is performed again and the stress results of the blade are extracted. After comparing with the blade before optimization, it is found that the maximum stress value of the optimized blade is 88.14 MPa, which is 13.66% lower than that before optimization; the mass of a single blade is reduced by 1.10 kg, which is 19.12% lower than that of a single blade before optimization, as shown in Table 1 below.

[0070] Table 1: Comparison of blades before and after optimization at 1900 rpm

[0071] Those skilled in the art should understand that the sequence numbers or order of description of the various embodiments in this application are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. Furthermore, the above embodiments are only optional implementations of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

[0072] Those skilled in the art should also understand that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

Claims

1. A blade, characterized in that, include: The blade body (10) includes a windward side and a leeward side arranged opposite to each other, and a leading edge sidewall (101), an inner edge sidewall (102), a trailing edge sidewall (103) and an outer edge sidewall (104) formed on the outer periphery of the windward side and the leeward side. A first groove (20) is provided on the windward side of the blade body (10). The first groove (20) includes a first front side groove wall (201), a first inner side groove wall (202), a first tail side groove wall (203), and a first outer side groove wall (204) connected end to end. The first front side groove wall (201) is disposed corresponding to and close to the front edge side wall (101), the first inner side groove wall (202) is disposed corresponding to and close to the inner edge side wall (102), the first tail side groove wall (203) is disposed corresponding to and close to the tail edge side wall (103), and the first outer side groove wall (204) is disposed corresponding to and close to the outer edge side wall (104).

2. The blade according to claim 1, characterized in that, The first front side groove wall (201) and the first outer side groove wall (204) have a connection point A, the first outer side groove wall (204) and the first tail side groove wall (203) have a connection point B, and the first tail side groove wall (203) and the first inner side groove wall (202) have a connection point C. The minimum distance between point A and the leading edge sidewall (101) is d1, the minimum distance between point A and the outer edge sidewall (104) is d2, the minimum distance between point B and the trailing edge sidewall (103) is d3, and the minimum distance between point C and the inner edge sidewall (102) is d4. The relationships between d1, d2, d3, and d4 are as follows: d1 < d2 < d3 < d4.

3. The blade according to claim 2, characterized in that, 30mm≤d1≤35mm; 35mm≤d2≤40mm; 50mm≤d3≤60mm; 60mm≤d4≤70mm.

4. The blade according to claim 1, characterized in that, The shape of the first groove (20) is adapted to the shape of the blade body (10); and / or The connection point between adjacent groove walls in the first groove (20) has a rounded corner, and the radius r of the rounded corner satisfies: 1.5mm≤r≤2.5mm.

5. The blade according to claim 1, characterized in that, The area of ​​the blade body (10) is S1, and the projected area of ​​the first groove (20) on the blade body (10) is S2, wherein the ratio k1 between S2 and S1 satisfies: 0.7≤k1≤0.75; And / or, The thickness of the blade body (10) is H1, and the groove depth of the first groove (20) is H2, where H2 = 15% * H1 ~ 25% * H1.

6. The blade according to any one of claims 1-5, characterized in that, The windward side of the blade body (10) is also provided with a second groove (30). The projected area S3 of the second groove (30) on the blade body (10) is smaller than the projected area S2 of the first groove (20) on the blade body (10). The second groove (30) is opened between the first front side groove wall (201) and the leading edge side wall (101).

7. The blade according to claim 6, characterized in that, The ratio k2 between S2 and S3 satisfies: 4.9 ≤ k2 ≤ 5.

3.

8. The blade according to claim 6, characterized in that, The groove depth of the first groove (20) is H2, and the groove depth of the second groove (30) is H3, wherein the ratio k3 between H2 and H3 satisfies: 0.56≤k3≤0.

67.

9. The blade according to claim 6, characterized in that, The first front side groove wall (201) and the first outer side groove wall (204) have a connection point A, and the first front side groove wall (201) and the first inner side groove wall (202) have a connection point D. The second groove (30) is positioned close to point D relative to points A and D.

10. The blade according to claim 9, characterized in that, The second groove (30) is a rectangular groove, and the second groove (30) includes a second front side groove wall (301), a second inner side groove wall (302), a second tail side groove wall (303), and a second outer side groove wall (304) connected end to end. The second front side groove wall (301) is provided as one long side of the second groove (30) and close to the front edge side wall (101), and the second tail side groove wall (303) is provided as the other long side of the second groove (30) and close to the first front side groove wall (201).

11. The blade according to claim 10, characterized in that, One end of the second tail side groove wall (303) is located at point D, and the other end extends toward point A. The extension length of the second tail side groove wall (303) is L2, and the extension length of the first front side groove wall (201) is L1. The ratio k4 between L2 and L1 satisfies: 0.19≤k4≤0.

26.

12. The blade according to any one of claims 1-5 and 7-11, characterized in that, The inner edge sidewall (102) of the blade body (10) is also provided with a connector (40) for connecting the blade body (10) to the blade hub, and the trailing edge sidewall (103) of the blade body (10) is also provided with a serrated structure (50).

13. An axial flow fan, characterized in that, The blade used is any one of claims 1-12.

14. An air supply device, characterized in that, Includes the axial flow fan as described in claim 13.

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