Impeller with S-shaped blades and axial flow fan applying same

Abstract

The invention relates to the technical field of axial flow fans, in particular to an impeller with S-shaped blades and an axial flow fan applying the impeller. On the axial projection of the impeller, the peripheral contour of each blade is defined by a blade root edge, a blade front edge, a blade outer edge and a blade rear edge, and the blade root edge is connected with the hub; the blade front edge and the blade rear edge are both wavy curves, and the blade root edge and the blade outer edge are both arc-shaped lines with the axis O of the hub as the circle center. Each blade is provided with a pressure face and a suction face, the pressure faces and the suction faces are oppositely arranged, and on the radial projection of the impeller, the pressure faces are arranged in a wave shape in a protruding mode from one end of the blade root edge to one end of the blade rear edge towards the suction faces and then concavely arranged, so that the blades are of an S-shaped structure. The problem that a traditional blade structure cannot meet the use requirements of high efficiency and low noise can be solved.

Description

Technical Field

[0001] This invention relates to the field of axial flow fan technology, and more particularly to an impeller with S-shaped blades and an axial flow fan using the same. Background Technology

[0002] Axial flow fans, with their significant advantages such as large air volume, compact structure, and convenient installation, have been widely used in many fields, including building ventilation, central air conditioning systems, industrial equipment cooling, and rail transit ventilation, becoming core equipment for ensuring air circulation and temperature control in various scenarios. The blades, as the core components of axial flow fans that realize energy conversion and airflow transport, directly determine the key performance indicators of the fan, such as air volume, air pressure, energy conversion efficiency, and operating noise. These are core factors affecting the overall performance and market competitiveness of the fan.

[0003] Currently, most axial fan blades on the market employ simple curves such as straight lines or circular arcs for their leading and trailing edges. This traditional structure has significant drawbacks in actual operation: Firstly, simple curves are difficult to adapt to the flow characteristics of airflow at different radial positions, failing to smoothly guide airflow onto the blade surface. This easily leads to premature airflow separation, generating numerous eddies and causing severe flow losses, thus hindering the improvement of the fan's energy conversion efficiency. Secondly, turbulence easily occurs when airflow converges at the trailing edge of the simple curve, increasing form drag and forming periodic Karman vortex streets. Furthermore, the superposition of the leading-edge concentrated vortex and the tip clearance leakage vortex generates significant noise pollution, affecting the user experience.

[0004] With the deepening of the concept of energy conservation and environmental protection and the upgrading of market demand for high-performance equipment, traditional blade structures can no longer meet the requirements of high efficiency and low noise. Summary of the Invention

[0005] One objective of this invention is to propose an impeller with S-shaped blades to address the challenge that traditional blade structures cannot meet the requirements for high efficiency and low noise.

[0006] Another object of the present invention is to provide an axial flow fan that uses an impeller with S-shaped blades as described above.

[0007] To achieve this objective, the present invention adopts the following technical solution: An impeller with S-shaped blades includes a hub and a plurality of blades, wherein the plurality of blades are circumferentially spaced around the hub, the hub has a rotation axis, the center point of the hub is defined as the axis O, the projection of the direction parallel to the rotation axis is defined as the axial projection of the impeller, and the projection of the direction perpendicular to the rotation axis is defined as the radial projection of the impeller. On the axial projection of the impeller, the peripheral contour of the blade is formed by the blade root edge, the blade leading edge, the blade outer edge and the blade trailing edge, and the blade root edge is connected to the hub; The leading edge and trailing edge of the leaf are both wavy curves, and the root edge and outer edge of the leaf are both arc-shaped lines centered on the axis O. The blade has a pressure surface and a suction surface. The pressure surface and the suction surface are arranged opposite to each other. In the radial projection of the impeller, the pressure surface is arranged in a wave shape that protrudes from one end of the blade root edge to one end of the blade trailing edge toward the suction surface and then is concave, so that the blade has an S-shaped structure.

[0008] Preferably, on the axial projection of the impeller, the connection points between the blade root edge, blade leading edge, blade outer edge and blade trailing edge are defined as design point A2, design point A1, design point B1 and design point B2, respectively. The leading edge of the leaf is controlled by curve A1A2, and the trailing edge of the leaf is controlled by curve B1B2; The straight line connecting design point A1 and design point A2 is defined as the leading edge chord A1A2 of the blade leading edge; The leading edge chord line A1A2 and the leading edge of the leaf intersect at design point A3. Design point A3 divides the leading edge of the leaf into a leading edge front section and a leading edge rear section. The leading edge front section is controlled by curve A2A3, and the leading edge rear section is controlled by curve A1A3. The leading edge front section is concave towards the side closer to the leading edge of the leaf relative to the leading edge chord line A1A2, and the leading edge rear section is convex towards the side farther from the leading edge of the leaf relative to the leading edge chord line A1A2. The point on the leading edge of the blade that has the maximum vertical distance relative to the leading edge chord line A1A2 is defined as design point A4, and the vertical distance from design point A4 to the leading edge chord line A1A2 is defined as L. A1 ; Design point A5 is defined as the point on the trailing segment of the blade leading edge that has the maximum vertical distance relative to the blade leading edge chord line A1A2. The vertical distance L from design point A5 to the blade leading edge chord line A1A2 is defined as L. A2 ; Among them, L A1 >L A2 .

[0009] Preferably, the length of the leading edge chord line A1A2 of the leaf is defined as L. A0 ; The length of the straight line from design point A1 to design point A3 is defined as L. A3 ; Among them, L A1 = (8% - 14%)L A0 LA2 = (3% - 8%)L A0 L A3 =(40%-60%)L A0 .

[0010] Preferably, on the axial projection of the impeller, the diameter of the impeller is defined as D, and the radius of the hub is defined as R. h The diameter of the hub is D. h ; Define the straight-line distance from the design point A1 to the axis O as R. A1 Define the straight-line distance from the design point A2 to the axis O as R. A2 The straight-line distance from the design point A3 to the axis O is defined as R. A3 Define the straight-line distance from the design point A4 to the axis O as R. A4 Define the straight-line distance from the design point A5 to the axis O as R. A5 ; Among them, D h / D=0.311; R A1 =D / 2;R A2 =R h ;R A4 / R A1 =0.4-0.5; R A3 / R A1 =0.6-0.7; R A5 / R A1 =0.8-0.9.

[0011] Preferably, the straight line connecting the design point B1 and the design point B2 is defined as the trailing edge chord B1B2 of the leaf trailing edge; The trailing edge chord line B1B2 and the trailing edge of the leaf intersect at design point B3. Design point B3 divides the trailing edge of the leaf into a front section and a rear section. The front section (41) of the trailing edge is controlled by curve B2B3, and the rear section is controlled by curve B1B3. The front section of the trailing edge protrudes away from the front edge of the leaf relative to the trailing edge chord line B1B2, and the rear section of the trailing edge is concave towards the front edge of the leaf relative to the trailing edge chord line B1B2. The point on the leading edge of the leaf blade with the maximum vertical distance relative to the trailing edge chord line B1B2 is defined as design point B4, and the vertical distance from design point B4 to the trailing edge chord line B1B2 is defined as L. B1 ; The point on the trailing edge of the blade with the maximum vertical distance relative to the trailing edge chord line B1B2 is defined as design point B5, and the vertical distance from design point B5 to the leading edge chord line B1B2 is defined as L.B2 ; Among them, L B1 <L B2 .

[0012] Preferably, the length of the trailing edge chord line B1B2 is defined as L. B0 ; Define the length of the straight line connecting design point B1 and design point B3 as L. B3 ; Among them, L B1 = (6% - 11%)L B0 L B2 = (7% - 13%)L B0 L B3 =(40%-60%)L B0 .

[0013] Preferably, on the axial projection of the impeller, the diameter of the impeller is defined as D, and the radius of the hub is defined as R. h The diameter of the hub is D. h ; Define the straight-line distance from the design point B1 to the axis O as R. B1 Define the straight-line distance from the design point B2 to the axis O as R. B2 Define the straight-line distance from the design point B3 to the axis O as R. B3 Define the straight-line distance from the design point B4 to the axis O as R. B4 Define the straight-line distance from the design point B5 to the axis O as R. B5 ; Among them, D h / D=0.311; R B1 =D / 2;R B2 =R h ;R B4 / R B1 =0.4-0.5; R B3 / R B1 =0.6-0.7; R B5 / R B1 =0.8-0.9.

[0014] Preferably, a Cartesian coordinate system is established on the axial projection of the impeller with the axis center O as the origin, and the curves A1A2 and B1B2 are fitted using the blade profile formula: y = ax 6 +bx 5 +cx 4 +dx 3 +ex 2 +fx+g; Wherein, for the curve A1A2, a = -1.000 × 10 -11 b = 1.000 × 10 -8 c = -5.000 × 10 -6 , d=0.0009, e=-0.0756, f=2.7667, g=-41.281; For the curve B1B2, a = -2.000 × 10 -12 b = 3.000 × 10 -9 c = -2.000 × 10 -6 , d=0.0006, e=-0.1022, f=9.2278, g=-234.26.

[0015] Preferably, between the leaf root edge and the leaf outer edge, leaf sections of different leaf heights are cut at equal intervals, and several leaf installation angles α are obtained from the leaf sections of different leaf heights. The variation law of the several leaf installation angles α is that they gradually decrease from the leaf root edge to the leaf outer edge.

[0016] An axial flow fan that uses an impeller with S-shaped blades as described above.

[0017] One of the above technical solutions has the following beneficial effects: 1. Improve aerodynamic efficiency: The wavy curve of the leading edge of the blade can smoothly guide the incoming flow at different radial positions to adhere to the blade surface, delay airflow separation, and reduce flow loss caused by eddies; the curve design of the trailing edge of the blade reduces form drag, and the S-shaped overall structure optimizes the airflow path and improves the impeller energy conversion efficiency.

[0018] 2. Reduce operating noise: The leading edge of the blade disperses concentrated vortices, avoiding the superposition of pulse noise; the trailing edge of the blade suppresses the formation of periodic Karman vortex streets, while reducing the influence of leakage vortices in the blade tip clearance, achieving noise reduction from multiple noise sources and improving the user experience.

[0019] 3. Enhanced operational stability: The arc-shaped design of the blade root edge and the outer edge of the blade, combined with the S-shaped structure of the blade, ensures that the force is evenly distributed when the blade rotates, reduces vibration, and extends the service life of the impeller; the standardized structural design also facilitates mass production and installation and maintenance.

[0020] 4. Adapting to high-performance requirements: The overall design specifically addresses the shortcomings of traditional simple curved blades, ensuring the core advantage of "large air volume" of axial flow fans while achieving a synergy of high efficiency and low noise, meeting the needs of energy conservation, environmental protection, and high-performance upgrades in the market. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the axial projection of an impeller with S-shaped blades; Figure 2 This is a radial projection schematic diagram of a portion of the structure of an impeller with S-shaped blades; Figure 3 This is a schematic diagram of the axial projection of the blades in an impeller with S-shaped blades; Figure 4 This is a schematic diagram of the leading edge design of the blades in an impeller with S-shaped blades; Figure 5 This is a schematic diagram of the trailing edge design of a blade in an impeller with S-shaped blades; Figure 6 This is a schematic diagram showing the design of the radius of the leading edge of the blades in an impeller with S-shaped blades; Figure 7 This is a schematic diagram showing the design of the radius of the trailing edge of a blade in an impeller with S-shaped blades; Figure 8 This is a schematic diagram of the blade cross-section design in an impeller with S-shaped blades; In the attached diagram: leaf root edge 1, leaf leading edge 2, leaf outer edge 3, leaf trailing edge 4, blade 10, hub 20, front section of leaf leading edge 21, rear section of leaf leading edge 22, impeller 30, front section of leaf trailing edge 41, rear section of leaf trailing edge 42, pressure surface 101, suction surface 102. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "left," "right," "vertical," "level," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] An impeller with S-shaped blades includes a hub 20 and a plurality of blades 10, wherein the plurality of blades 10 are circumferentially spaced around the hub 20, the hub 20 has a rotation axis, the center point of the hub 20 is defined as the axis O, the projection of the direction parallel to the rotation axis is defined as the axial projection of the impeller 30, and the projection of the direction perpendicular to the rotation axis is defined as the radial projection of the impeller 30. On the axial projection of the impeller 30, the peripheral contour of the blade 10 is formed by the blade root edge 1, the blade leading edge 2, the blade outer edge 3 and the blade trailing edge 4, and the blade root edge 1 is connected to the hub 20. The leading edge 2 and the trailing edge 4 of the leaf are both wavy curves, and the root edge 1 and the outer edge 3 of the leaf are both arc-shaped lines with the axis O as the center. The blade 10 has a pressure surface 101 and a suction surface 102. The pressure surface 101 and the suction surface 102 are arranged opposite to each other. In the radial projection of the impeller 30, the pressure surface 101 is arranged in a wave shape that protrudes from one end of the blade root edge 1 to one end of the blade trailing edge 4 toward the suction surface 102 and then is concave, so that the blade 10 has an S-shaped structure.

[0027] like Figure 1-7 As shown, when the impeller 30 is running, the hub 20 rotates around the rotation axis, driving several blades 10 to rotate synchronously. In the axial projection, the circular arc design of the blade root edge 1 and the blade outer edge 3 with the axis O as the center ensures that the radial force is balanced when the blade 10 rotates, avoiding local stress concentration; the wavy curves of the blade leading edge 2 and the blade trailing edge 4 can adapt to the flow characteristics of airflow at different radial positions, guiding the airflow to smoothly enter and exit the blade 10.

[0028] In radial projection, the pressure surface 101 of the blade 10 has a wave-like shape that is both convex and concave, forming an S-shaped structure. When the airflow passes through the blade 10, a stable pressure difference is formed between the pressure surface 101 and the suction surface 102 of the S-shaped structure, which drives the airflow to flow efficiently along the axial direction. At the same time, the wave-shaped leading edge 2 can disperse the concentrated leading edge vortex into multiple low-intensity vortices, and the smooth curve of the trailing edge 4 guides the airflow on the upper and lower surfaces to merge smoothly. Combined with the structural design of the blade, this effectively reduces airflow turbulence.

[0029] To further explain, on the axial projection of the impeller 30, the connection points between the blade root edge 1, the blade leading edge 2, the blade outer edge 3, and the blade trailing edge 4 are defined as design point A2, design point A1, design point B1, and design point B2, respectively. The leading edge 2 of the blade is controlled and set by curve A1A2, and the trailing edge 4 of the blade is controlled and set by curve B1B2; The straight line connecting design point A1 and design point A2 is defined as the leading edge chord A1A2 of the leading edge 2 of the blade; The leading edge chord A1A2 and the leading edge 2 intersect at design point A3. Design point A3 divides the leading edge 2 into a leading edge front section 21 and a leading edge rear section 22. The leading edge front section 21 is controlled by curve A2A3, and the leading edge rear section (22) is controlled by curve A1A3. The leading edge front section 21 is concave relative to the leading edge chord A1A2 towards the side closer to the leading edge 4, and the leading edge rear section 22 is convex relative to the leading edge chord A1A2 towards the side farther from the leading edge 4. The point on the leading edge segment 21 of the blade that has the maximum vertical distance relative to the leading edge chord line A1A2 is defined as design point A4, and the vertical distance from design point A4 to the leading edge chord line A1A2 is defined as L. A1 ; The point on the trailing segment 22 of the blade leading edge that has the maximum vertical distance relative to the chord line A1A2 of the blade leading edge is defined as design point A5, and the vertical distance from design point A5 to the chord line A1A2 of the blade leading edge is defined as L. A2 ; Among them, L A1 >L A2 .

[0030] like Figure 3-4 As shown, on the axial projection of the impeller 30, the leading edge 2 of the blade achieves a wave-like structure through curve A1A2 (controlled by design points A1, A2, A3, A4, and A5). When the airflow impacts the leading edge 2, it first contacts the leading edge section 21, which is concave towards the trailing edge 4 relative to the leading edge chord A1A2, initially guiding the airflow into the blade 10. Subsequently, the airflow flows through the trailing edge section 22, which bulges away from the trailing edge 4, further diverting the airflow and preventing it from accumulating at the leading edge 2. Simultaneously, design points A4 (the point of maximum vertical distance of the leading edge section 21) and A5 (the point of maximum vertical distance of the trailing edge section 22) form a "main diversion point + secondary diversion point" combination, where L... A1 >L A2 This makes the leading edge 21 of the blade more effective in guiding the airflow, allowing it to handle most of the airflow first, while the trailing edge 22 of the blade assists in diverting the remaining airflow, thus achieving stratified airflow guidance and reducing mutual interference between airflows.

[0031] To further clarify, the length of the leading edge chord A1A2 of the leaf is defined as L. A0 ; The length of the straight line from design point A1 to design point A3 is defined as L. A3 ; Among them, L A1 = (8% - 14%)L A0 L A2 = (3% - 8%)L A0 L A3 =(40%-60%)L A0 .

[0032] like Figure 4 As shown, through the above-mentioned limiting relationship, the depth ratio of the leading edge section 21 and the trailing edge section 22 relative to the leading edge chord A1A2 is clarified, ensuring that the main diversion effect of the leading edge section 21 and the secondary diversion effect of the trailing edge section 22 are matched, avoiding airflow guidance failure due to depth imbalance (such as the leading edge section 21 being too shallow to effectively divert airflow, or the trailing edge section 22 being too deep to interfere with airflow); L A3 Further restrictions are made to rationally divide the segmented regions of the leading edge 2 of the blade, so that the length ratio of the leading edge 21 to the trailing edge 22 of the blade is adapted to the flow path of the airflow in the leading edge 2 of the blade, ensuring that the airflow has enough space to complete the stratification and guidance, and avoiding the airflow compression and turbulence caused by the segment being too short.

[0033] To further explain, on the axial projection of the impeller 30, the diameter of the impeller 30 is defined as D, and the radius of the hub 20 is defined as R. h The diameter of the hub 20 is D. h ; Define the straight-line distance from the design point A1 to the axis O as R. A1 Define the straight-line distance from the design point A2 to the axis O as R. A2 The straight-line distance from the design point A3 to the axis O is defined as R. A3 Define the straight-line distance from the design point A4 to the axis O as R. A4 Define the straight-line distance from the design point A5 to the axis O as R. A5 ; Among them, D h / D=0.311; R A1 =D / 2;R A2 =R h ;R A4 / R A1 =0.4-0.5; R A3 / R A1 =0.6-0.7; R A5 / R A1 =0.8-0.9.

[0034] like Figure 6 As shown, when the impeller 30 rotates, different radial positions correspond to different linear velocities (linear velocity is positively correlated with radius), R A1 The linear velocity is greatest at the outer edge of the leaf, R. A2 The linear velocity is minimum at the blade root. By limiting the radius of each design point, the wavy curve of the blade leading edge 2 at different radial positions is adapted to the airflow velocity at the corresponding linear velocity, avoiding airflow velocity mismatch at different positions of the blade leading edge 2 due to radial velocity differences (such as airflow being too fast at the blade tip and too slow at the blade root), and ensuring that the airflow flows uniformly along the radial direction of the blade leading edge 2.

[0035] In a preferred embodiment, R A4 / R A1 =0.462; R A3 / R A1 =0.623; R A5 / R A1 =0.862.

[0036] To further explain, the straight line connecting the design point B1 and the design point B2 is defined as the trailing edge chord B1B2 of the trailing edge 4 of the blade. The trailing edge chord line B1B2 and the trailing edge 4 intersect at design point B3. Design point B3 divides the trailing edge 4 into a trailing edge front section 41 and a trailing edge rear section 42. The trailing edge front section 41 is controlled by curve B2B3, and the trailing edge rear section 42 is controlled by curve B1B3. The trailing edge front section 41 protrudes away from the trailing edge 2 relative to the trailing edge chord line B1B2, and the trailing edge rear section 42 is concave towards the trailing edge (2) relative to the trailing edge chord line B1B2. The point on the leading edge 41 of the blade trailing edge that has the maximum vertical distance relative to the trailing edge chord line B1B2 is defined as the design point B4, and the vertical distance from the design point B4 to the trailing edge chord line B1B2 is defined as L. B1 ; The point on the trailing edge 42 of the blade that has the maximum vertical distance relative to the trailing edge chord line B1B2 is defined as design point B5, and the vertical distance from design point B5 to the leading edge chord line B1B2 is defined as L. B2 ; Among them, L B1 <L B2 .

[0037] like Figure 3 and 5As shown, on the axial projection of the impeller 30, the trailing edge 4 of the blade achieves a wave-like structure through curves B1B2 (controlled by design points B1, B2, B3, B4, and B5). After the airflow passes through the blade 10, it flows out from the trailing edge 4. The leading section 41 of the trailing edge bulges away from the leading edge 2 relative to the trailing edge chord B1B2, which can guide the airflow of the pressure surface 101 to flow out smoothly; the trailing section 42 of the trailing edge is concave towards the leading edge 2, which guides the airflow of the suction surface 102 to flow out smoothly. Design points B4 (the point of maximum vertical distance of the leading section) and B5 (the point of maximum vertical distance of the trailing section) form an "auxiliary confluence point + main confluence point" combination, L B1 <L B2 This makes the confluence effect of the trailing edge 42 of the blade stronger, which can efficiently merge the airflow on the pressure surface and the suction surface, and avoid the airflow colliding with each other at the trailing edge 4 of the blade.

[0038] To further clarify, the length of the trailing edge chord B1B2 is defined as L. B0 ; Define the length of the straight line connecting design point B1 and design point B3 as L. B3 ; Among them, L B1 = (6% - 11%)L B0 L B2 = (7% - 13%)L B0 L B3 =(40%-60%)L B0 .

[0039] like Figure 5 As shown, the indentation depth and segment length of the trailing edge 4 of the leaf are clearly defined through the above-mentioned limiting relationship. B2 >L B1 The proportional design ensures that the main confluence effect of the trailing edge 42 is stronger than the auxiliary confluence effect of the trailing edge 41, which can preferentially converge most of the airflow and avoid airflow accumulation; L B3 Further restrictions are imposed to rationally divide the segmented region of the trailing edge 4 of the blade, ensuring that the leading section 41 and the trailing section 42 of the trailing edge of the blade have sufficient space to complete the airflow guidance and convergence.

[0040] To further explain, on the axial projection of the impeller 30, the diameter of the impeller 30 is defined as D, and the radius of the hub is defined as R. h The diameter of the hub is D. h ; Define the straight-line distance from the design point B1 to the axis O as R. B1 Define the straight-line distance from the design point B2 to the axis O as R. B2 Define the straight-line distance from the design point B3 to the axis O as R. B3Define the straight-line distance from the design point B4 to the axis O as R. B4 Define the straight-line distance from the design point B5 to the axis O as R. B5 ; Among them, D h / D=0.311; R B1 =D / 2;R B4 / R B1 =0.4-0.5; R B3 / R B1 =0.6-0.7; R B5 / R B1 =0.8-0.9.

[0041] like Figure 6-7 As shown, when the impeller 30 rotates, the design points at different radial positions of the trailing edge 4 correspond to different linear velocities, R. B1 The linear velocity is greatest at the (leaf tip) point, R. B2 The linear velocity is minimum at the blade root. By limiting the radius of each design point, the wavy curve of the blade trailing edge 4 is adapted to the outflow velocity of the airflow at different radial positions, avoiding the occurrence of velocity discontinuity at the blade trailing edge 4 due to radial velocity differences (such as the airflow being too fast at the outer edge of the blade and too slow at the blade root), and ensuring that the airflow converges and flows out uniformly along the radial direction of the blade trailing edge 4.

[0042] In a preferred embodiment, R B4 / R B1 =0.474; R B3 / R B1 =0.698; R B5 / R B1 =0.877.

[0043] To further explain, a Cartesian coordinate system is established on the axial projection of the impeller 30 with the axis center O as the origin, and the curves A1A2 and B1B2 are fitted using the blade profile formula: y = ax 6 +bx 5 +cx 4 +dx 3 +ex 2 +fx+g; Wherein, for the curve A1A2, a = -1.000 × 10 -11 b = 1.000 × 10 -8 c = -5.000 × 10 -6 , d=0.0009, e=-0.0756, f=2.7667, g=-41.281; For the curve B1B2, a = -2.000 × 10-12 b = 3.000 × 10 -9 c = -2.000 × 10 -6 , d=0.0006, e=-0.1022, f=9.2278, g=-234.26.

[0044] Specifically, on the axial projection of the impeller 30, a Cartesian coordinate system is established with the axis center O as the origin, using the sixth-degree polynomial y=ax. 6 +bx 5 +cx 4 +dx 3 +ex 2 The leading edge curve A1A2 and trailing edge curve B1B2 are fitted using +fx+g, respectively. A sixth-order polynomial ensures high-order continuity of the curves, guaranteeing no abrupt changes in curvature between the leading edge 2 and trailing edge 4. When airflow passes through the leading edge 2 and trailing edge 4, the continuously changing curvature guides the airflow smoothly along the curved surface, preventing airflow separation due to abrupt curvature changes and improving the aerodynamic efficiency of the impeller 30. Simultaneously, specific coefficients for the two curves allow for precise control of the curvature and direction of the leading edge curve A1A2 and trailing edge curve B1B2. This not only avoids the poor airflow guidance effect of traditional simple curves (straight lines, arcs) but also ensures that the leading edge curve A1A2 and trailing edge curve B1B2 are adapted to the aerodynamic requirements of the impeller 30, guaranteeing effective airflow guidance.

[0045] To further explain, between the leaf root edge 1 and the leaf outer edge 3, leaf sections of the leaf 1 at different leaf heights are cut at equal intervals, and several leaf installation angles α are obtained from the leaf sections of different leaf heights. The variation law of the several leaf installation angles α is that they gradually decrease from the leaf root edge 1 to the leaf outer edge 3.

[0046] like Figure 8 As shown, when the impeller 30 rotates, the linear velocity at the blade root edge 1 is low. A larger installation angle increases the contact area between the blade 10 and the airflow, ensuring a sufficient pressure difference at the blade root edge 1 to drive the airflow. The linear velocity at the outer edge 3 is high. A smaller installation angle avoids excessive impact between the airflow and the blade 10, reducing airflow loss. The gradual design of different blade height installation angles ensures that the blade 10 is adapted to the airflow velocity throughout the entire radial range, forming a uniform pressure gradient and driving the airflow to flow smoothly along the axial direction.

[0047] In one specific embodiment, nine blade sections, including the leaf root edge 1 and the leaf outer edge 3, are cut at equal intervals. The blade installation angles α at the blade sections from the leaf root edge 1 to the leaf outer edge 3 are 24.44°, 24.08°, 23.08°, 21.21°, 20.28°, 18.96°, 18.27°, 17.07°, and 16.46°, respectively.

[0048] An axial flow fan that uses an impeller with S-shaped blades as described above.

[0049] Specifically, during operation, the motor drives the impeller 30, which has S-shaped blades, to rotate. The impeller 30, through the S-shaped structure of the blades 10, the wavy leading and trailing edges, and the gradually changing installation angle, smoothly draws airflow into the axial flow fan inlet. After rectification and pressurization by the blades 10, the airflow is pushed axially to the outlet of the axial flow fan, achieving the characteristics of "high efficiency, low noise, and stability." Thus, in scenarios such as ventilation, air conditioning systems, and industrial cooling, it can both guarantee large air volume requirements and reduce operating noise, improving the user experience.

[0050] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these equivalent variations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. An impeller having S-shaped vanes, characterized by, The impeller (30) comprises a hub (20) and a plurality of blades (10), the plurality of blades (10) are spaced around the circumference of the hub (20), the hub (20) has a rotation axis, the center point of the hub (20) is defined as the axis center O, the direction projection parallel to the rotation axis is defined as the axial projection of the impeller (30), and the direction projection perpendicular to the rotation axis is defined as the radial projection of the impeller (30); In the axial projection of the impeller (30), the peripheral contour of the blade (10) is formed by the blade root edge (1), the blade leading edge (2), the blade outer edge (3) and the blade trailing edge (4), and the blade root edge (1) is connected with the hub (20); The blade leading edge (2) and the blade trailing edge (4) are both wave-shaped curves, and the blade root edge (1) and the blade outer edge (3) are both circular arc lines with the axis center O as the center; The blade (10) has a pressure surface (101) and a suction surface (102), the pressure surface (101) is arranged opposite to the suction surface (102), in the radial projection of the impeller (30), the pressure surface (101) is arranged in a wave shape from one end of the blade root edge (1) to one end of the blade trailing edge (4) to the suction surface (102) and then recessed, so that the blade (10) has an S-shaped structure.

2. An impeller having S-shaped blades according to claim 1, characterized in that In the axial projection of the impeller (30), the connecting points between the blade root edge (1), the blade leading edge (2), the blade outer edge (3) and the blade trailing edge (4) are defined as design points A2, A1, B1 and B2 in sequence; The blade leading edge (2) is arranged by a curve A1A2, and the blade trailing edge (4) is arranged by a curve B1B2; A straight line connecting the design points A1 and A2 is defined as a blade leading edge chord line A1A2 of the blade leading edge (2); The blade leading edge chord line A1A2 and the blade leading edge (2) intersect at a design point A3, the design point A3 divides the blade leading edge (2) into a blade leading edge front section (21) and a blade leading edge rear section (22), the blade leading edge front section (21) is arranged by a curve A2A3, the blade leading edge rear section (22) is arranged by a curve A1A3, and the blade leading edge front section (21) is recessed relative to the blade leading edge chord line A1A2 towards the side close to the blade trailing edge (4), and the blade leading edge rear section (22) is convex relative to the blade leading edge chord line A1A2 towards the side away from the blade trailing edge (4); A point on the leading edge front section (21) having the maximum perpendicular distance relative to the leading edge chord line A1A2 is defined as a design point A4, and the perpendicular distance of the design point A4 to the leading edge chord line A1A2 is defined as L A1 ; A point on the rear section (22) of the leading edge of the blade having the maximum perpendicular distance relative to the chord line A1A2 of the leading edge of the blade is defined as a design point A5, and the perpendicular distance of the design point A5 to the chord line A1A2 of the leading edge of the blade is defined as L A2 ; wherein L A1 > L A2 .

3. An impeller having S-shaped blades according to claim 2, characterized in that The length of the chord line A1A2 defining the leading edge of the blade is L A0 ; The length of the straight line from the design point A1 to the design point A3 is defined as L A3 ; wherein L A1 = (8-14%)L A0 ; L A2 = (3-8%)L A0 ; L A3 = (40-60%)L A0 .

4. An impeller having S-shaped blades according to claim 2, wherein In an axial projection of the impeller (30), a diameter of the impeller (30) is defined as D, a radius of the hub (20) is defined as R h , a diameter of the hub (20) is D h ​ defining a straight line distance of the design point A1 to the axis center O as R A1 ; defining a straight line distance of the design point A2 to the axis center O as R A2 ; defining a straight line distance of the design point A3 to the axis center O as R A3 ; defining a straight line distance of the design point A4 to the axis center O as R A4 ; defining a straight line distance of the design point A5 to the axis center O as R A5 ; wherein D h D = 0.3-0.4; R A1 = D / 2; R A2 = D / 3; R h = D / 4; R A4 = D / 5; R A1 = 0.4-0.5; R A3 = 0.5-0.6; R A1 = 0.6-0.7; R A5 = 0.7-0.8; R A1 = 0.8-0.

9.

5. An impeller having S-shaped blades according to claim 2, wherein A straight line connecting the design points B1 and B2 is defined as a blade trailing edge chord line B1B2 of the blade trailing edge (4); The leaf trailing edge chord line B1B2 intersects with the leaf trailing edge (4) at a design point B3, the design point B3 divides the leaf trailing edge (4) into a leaf trailing edge front section (41) and a leaf trailing edge rear section (42), the leaf trailing edge front section (41) is controlled and arranged by the curve B2B3, the leaf trailing edge rear section (42) is controlled and arranged by the curve B1B3, and the leaf trailing edge front section (41) protrudes to a side away from the leaf leading edge (2) relative to the leaf trailing edge chord line B1B2, and the leaf trailing edge rear section (42) is recessed to a side close to the leaf leading edge (2) relative to the leaf trailing edge chord line B1B2; A point on the leading edge front section (41) having the maximum perpendicular distance relative to the blade trailing edge chord B1B2 is defined as a design point B4, and the perpendicular distance of the design point B4 to the blade trailing edge chord B1B2 is defined as L B1 ; A point on the rear section (42) of the blade trailing edge having the maximum perpendicular distance relative to the blade trailing edge chord B1B2 is defined as the design point B5, and the perpendicular distance of the design point B5 to the blade leading edge chord B1B2 is defined as L B2 ; L B1 L B2 .

6. An impeller having S-shaped vanes as defined in claim 5, characterized in that The length of the blade trailing edge chord line B1B2 is defined as L B0 ; The length of the straight line connecting the design point B1 to the design point B3 is defined as L B3 ; wherein L B1 = (6-11%)L B0 ; L B2 = (7-13%)L B0 ; L B3 = (40-60%)L B0 .

7. An impeller having S-shaped vanes as defined in claim 5, wherein In an axial projection of the impeller (30), a diameter of the impeller (30) is defined as D, a radius of the hub is defined as R h , and a diameter of the hub is D h . defining a straight line distance of the design point B1 to the axis center O as R B1 ; defining a straight line distance of the design point B2 to the axis center O as R B2 ; defining a straight line distance of the design point B3 to the axis center O as R B3 ; defining a straight line distance of the design point B4 to the axis center O as R B4 ; defining a straight line distance of the design point B5 to the axis center O as R B5 ; wherein D h / D = 0.311; R B1 =D / 2; R B4 / R B1 =0.4-0.5; R B3 / R B1 =0.6-0.7; R B5 / R B1 =0.8-0.

9.

8. An impeller having S-shaped vanes as defined in claim 2, wherein On the axial projection of the impeller (30), a Cartesian coordinate system is established with the shaft center O as the origin, and the curve A1A2 and the curve B1B2 are fitted by using a blade profile formula: y = ax 6 + bx 5 + cx 4 + dx 3 + ex 2 + fx + g; where, for the curve A1A2, a = -1.000xl0 -11 , b = 1.000xl0 -8 , c = -5.000xl0 -6 , d = 0.0009, e = -0.0756, f = 2.7667, g = -41.281; For the curve B1B2, a = -2.000xl0 -12 , b = 3.000xl0 -9 , c = -2.000xl0 -6 , d = 0.0006, e = -0.1022, f = 9.2278, g = -234.

26.

9. The impeller having S-type blades according to claim 1, wherein Between the leaf root edge (1) and the leaf outer edge (3), blade sections of different blade heights of the blade (1) are taken at equal intervals, a plurality of blade installation angles α are obtained from the blade sections of different blade heights, and the change rule of the plurality of blade installation angles α is gradually reduced from the leaf root edge (1) to the leaf outer edge (3).

10. An axial flow fan characterised in that, An impeller with S-shaped blades according to any one of claims 1-9.

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