Fan impeller and axial flow fan

Abstract

The fan impeller comprises a hub and a plurality of blades, the multiple blades are connected with the hub and distributed in the circumferential direction of the hub at intervals, and the stacking line of each blade is provided with an outer bent part protruding in the rotating direction of the blade and an inner bent part protruding in the air inlet side of the blade. The distance between the outer bent part and the blade root is 0.75 W to 0.85 W, and the distance between the inner bent part and the blade root is 0.15 W to 0.25 W. The blade height of about 0.2 W is bent inwards in the axial direction of the hub, the blade height of about 0.8 W is bent outwards in the circumferential direction of the hub, so that airflow at the blade root is not prone to separation during high-speed rotation, two airflow channels are formed, generation of blade frequency sound is weakened, noise is reduced, meanwhile, the blade height of 0.8 W is bent, and the blade height of about 0.2 W is bent outwards in the circumferential direction of the hub. And a high-pressure area of a blade tip area can be removed, so that the range of a high-efficiency area is enlarged while the aerodynamic efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of axial flow fans, and in particular to a fan impeller and an axial flow fan including the fan impeller. Background Art

[0002] As the demand for fans in various industries continues to increase, competition among fan companies is becoming increasingly fierce, and the requirements for fans are becoming higher and higher. In response to current market demand, designing fans with high efficiency, wide operating conditions, low noise and high safety has become the goal pursued by fan designers.

[0003] Axial flow fans occupy an extremely important position in ventilation machinery due to their large flow rate, small size and low pressure head. They are not only widely used in traditional industries such as electricity and metallurgy, but also in high-rise buildings, aerospace and other fields. There is a strong demand for axial flow fans. Especially with the emergence of new technologies, new industries and new fields, the performance requirements for axial flow fans are constantly increasing.

[0004] In the process of implementing the present invention, the inventors found that the prior art has at least the following problems:

[0005] Existing axial flow fans have low efficiency, narrow high efficiency range and high noise. Summary of the invention

[0006] In order to overcome the problems existing in the above-mentioned related technologies, the main purpose of the present application is to provide a fan impeller and an axial flow fan that can improve efficiency, reduce noise, and expand the high-efficiency range of the fan.

[0007] In order to achieve the above objectives, this application specifically adopts the following technical solutions:

[0008] The present application provides a fan impeller, the fan impeller comprising:

[0009] Wheel hub;

[0010] A plurality of blades, wherein the plurality of blades are respectively connected to the hub and are spaced apart along the circumference of the hub, and the stacking line of each blade has an outer curvature protruding toward the rotation direction of the blade and an inner curvature protruding toward the wind inlet side of the blade, and the distance between the outer curvature and the blade root is 0.75W to 0.85W, and the distance between the inner curvature and the blade root is 0.15W to 0.25W;

[0011] The stacking line is defined as a high-order spline curve formed by sequentially connecting the airfoil centroid points of each airfoil section of the blade from the root position of the blade to the blade tip, and W is the distance from the root to the blade tip of the blade.

[0012] In some embodiments, the offset amplitude of the stacking line relative to the reference line in the circumferential direction of the hub is in the range of -9%D to 4.5%D, and the offset amplitude of the stacking line relative to the reference line in the axial direction of the hub is in the range of -4%D to 1.5%D;

[0013] The connection point between the stacking line and the hub is defined as a reference point O, the normal line of the side surface of the hub passing through the reference point O is defined as a reference line, and D is the diameter of the fan impeller.

[0014] In some embodiments, the hub has a first surface, a second surface and a side surface, the first surface and the second surface are arranged opposite to each other, the two ends of the side surface are respectively connected to the first surface and the second surface, and the plurality of blades are respectively connected to the side surfaces.

[0015] In some embodiments, the side surface includes a first curved surface, a second curved surface, and a third curved surface. Along the direction from the first surface to the second surface, the first curved surface, the second curved surface, and the third curved surface are distributed in sequence, and the radius of the second curved surface is greater than the radius of the first curved surface, and the radius of the third curved surface is greater than the radius of the second curved surface.

[0016] In some embodiments, the blade is connected to the third arcuate surface and extends to the second arcuate surface.

[0017] In some embodiments, the ratio of the hub diameter to the fan impeller diameter ranges from 0.45 to 0.47.

[0018] In some embodiments, the installation angle β of the airfoil section is 22.5° to 37.8°.

[0019] In some embodiments, the chord length L of the airfoil section is 0.23D to 0.40D, wherein D is the diameter of the fan impeller.

[0020] In some embodiments, the airfoil thickness S of the airfoil section is 3.5%L to 13%L, wherein L is the chord length of the airfoil section.

[0021] In some embodiments, the camber range of the airfoil section is 0.0075-0.069, and the camber position of the airfoil section is 0.4-0.6.

[0022] Accordingly, the present application provides an axial flow fan, which includes a fan impeller as described in any of the above embodiments.

[0023] The fan impeller of the present application includes a hub and a plurality of blades, wherein the plurality of blades are connected to the hub respectively, and the plurality of blades are spaced apart along the circumference of the hub, and the stacking line of each blade has an outer curvature protruding toward the rotation direction of the blade and an inner curvature protruding toward the air inlet side of the blade, and the distance between the outer curvature and the blade root is 0.75W to 0.85W, and the distance between the inner curvature and the blade root is 0.15W to 0.25W. Compared with the prior art, the present application makes an axial inward bend along the hub at a blade height of about 0.2W, and an outward bend along the circumference of the hub at a blade height of about 0.8W, so that the airflow at the blade root is not easy to separate when rotating at high speed, forming two airflow channels, weakening the generation of blade frequency sound, and thus reducing noise. At the same time, the high-pressure area in the blade tip area can be removed by bending at a blade height of 0.8W, thereby increasing the range of the high-efficiency area while improving the aerodynamic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A front view of a fan impeller provided in an embodiment of the present application.

[0025] Figure 2 A rear view of the fan impeller provided in an embodiment of the present application.

[0026] Figure 3 A side view of a fan impeller provided in an embodiment of the present application.

[0027] Figure 4 A schematic diagram of the structure of a blade provided in an embodiment of the present application.

[0028] Figure 5 A schematic diagram of the forward bending of the stacking line provided in an embodiment of the present application.

[0029] Figure 6 A schematic diagram of a stacked line forward sweep provided in an embodiment of the present application.

[0030] Figure 7 A diagram of the hub structure provided for an embodiment of the present application.

[0031] Figure 8 A schematic diagram of the hub ratio and cross-section provided for an embodiment of the present application.

[0032] Fig. 9 A schematic diagram of an airfoil cross section provided in an embodiment of the present application.

[0033] Fig.10 A schematic diagram of airfoil thickness provided in an embodiment of the present application.

[0034] Figure ID:

[0035] 1. Hub; 11. First surface; 12. Second surface; 13. Side surface; 131. First curved surface; 132. Second curved surface; 133. Third curved surface; 2. Blade; 21. Suction surface; 22. Pressure surface; 23. Leading edge curve; 24. Trailing edge curve. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] In the description of this application, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0039] An external rotor fan is a fan with the stator in the middle of the motor and the rotor outside. The external rotor fan adopts an advanced structure in which the external rotor motor directly drives the impeller and a reasonable aerodynamic design. It has the characteristics of high efficiency, low noise, light weight, compact structure, and easy installation and maintenance. The rotor and the fan blades rotate outside the stator, which has the advantages of compact structure, space saving, and exquisite design. The motor is installed in the middle of the impeller, which achieves the maximum cooling effect on the motor itself.

[0040] At present, it is a general trend to develop high-efficiency energy-saving axial flow fans and low-noise environmentally friendly axial flow fans. Generally, high-efficiency axial flow fans are based on the design method of the primitive level, and the inventors have found in practice that blades with axial forward sweep and circumferential forward bending characteristics can improve the performance of axial flow fans and reduce their noise. Therefore, the inventors invented this application based on the combination of the primitive level design method and the sweep technology, so as to further improve the efficiency of the outer rotor axial flow fan, reduce its noise, and expand its high-efficiency range.

[0041] Reference Figure 1 and Figure 2 As shown, an embodiment of the present application discloses a fan impeller, which includes a hub 1 and a plurality of blades 2. The plurality of blades 2 are respectively connected to the hub 1, and the plurality of blades 2 are distributed at intervals along the circumference of the hub 1. During the rotation of the hub 1, the blades 2 can be driven to rotate to increase the gas pressure and discharge the gas, thereby achieving ventilation or air exchange.

[0042] Reference Figure 3 and Figure 4 As shown, each blade 2 includes a pressure curved surface 22, a suction curved surface 21, a leading edge curve 23 and a trailing edge curve 24. The pressure curved surface 22 and the suction curved surface 21 are arranged opposite to each other, the suction curved surface 21 is the windward side, and the pressure curved surface 22 is the leeward side. The leading edge curve 23 and the trailing edge curve 24 are arranged opposite to each other, and the leading edge curve 23 faces the rotation direction of the blade 2. When a series of coaxial cylindrical surfaces with different radii (for example, radii RH to RS) are intersected with the blade 2, a series of airfoil sections can be obtained, and the characteristics of each airfoil section are controlled by the installation angle, relative camber, relative position of camber, airfoil thickness and the shape characteristic parameters of the NACA airfoil.

[0043] Reference Figure 5 and Figure 6 As shown, the stacking line A is obtained by taking the centroid of each airfoil section of the blade 2 as the stacking point, wherein the stacking line A is a high-order spline curve formed by taking the airfoil centroid points of each airfoil section of the same blade 2 and connecting the airfoil centroid points of each airfoil section in sequence from the blade root position to the blade tip. Then the stacking line A of each blade 2 is arranged in an S shape along the circumference of the hub 1, and the stacking line A of each blade 2 is also arranged in an S shape along the axial direction of the hub 1. Specifically, along the circumference of the hub 1, the stacking line A has an outer curvature, which protrudes toward the rotation direction of the blade 2, and the outer curvature is located Figure 5 At P4 in FIG. 1 , the distance between the outer curved portion and the root of the blade 2 is 0.75W to 0.85W, and preferably, the distance between the outer curved portion and the root of the blade 2 is 0.8W; along the axial direction of the hub 1, the stacking line A has an inner curved portion, which protrudes toward the windward side of the blade 2, and the inner curved portion is located at Figure 6At Z2 in the figure, the distance between the inner curved portion and the root of blade 2 is 0.15W to 0.25W. Preferably, the distance between the inner curved portion and the root of blade 2 is 0.2W, wherein W is the distance from the root to the tip of blade 2. In this embodiment, the blade is bent inward along the axial direction of hub 1 at a blade height of about 0.2W, and is bent outward along the circumferential direction of hub 1 at a blade height of about 0.8W, so that the airflow at the root of the blade is not easily separated when rotating at high speed, forming two airflow channels, weakening the generation of blade frequency sound, and thus reducing noise. At the same time, the high-pressure area in the tip area can be removed by bending at a blade height of 0.8W, thereby increasing the range of the high-efficiency area while improving the aerodynamic efficiency.

[0044] Continue to refer to Figure 5 and Figure 6 As shown, the point where the stacking line A is located at the blade root is defined as the reference point O, and the normal line of the side surface of the hub 1 passing through the reference point O is defined as the reference line OQ. Then, the offset amplitude H1 of the stacking line A relative to the reference line OQ in the circumferential direction of the hub 1 is: -9%D≤H1≤4.5%D, and the offset amplitude H2 of the stacking line A relative to the reference line OQ in the axial direction of the hub 1 is: -4%D≤H2≤1.5%D. Exemplarily, the offset amplitude H1 of the stacking line A relative to the reference line OQ in the circumferential direction of the hub 1 can be 1%D~2%D, 3.5%D~4.5%D, -9%D~-8%D, -8%D~-7%D, etc.; the offset amplitude H2 of the stacking line A relative to the reference line OQ in the axial direction of the hub 1 is 0.5%D~1.5%D, -1%D~-2%D, -3.5%D~-2.5%D, -4%D~-3%D, etc., where D is the impeller diameter.

[0045] Also refer to Figure 3 and Figure 7 As shown, Figure 7 For the wheel hub structure diagram, Figure 7The solid line i in the figure rotates around the dotted line to obtain the shape diagram of the hub 1. The hub 1 has a first surface 11, a second surface 12 and a side surface 13. The first surface 11 and the second surface 12 are arranged opposite to each other. The two ends of the side surface 13 are connected to the first surface 11 and the second surface 12 respectively, forming a hub 1 with a cylindrical structure. The side surface 13 includes a first arc surface, a second arc surface and a third arc surface. The first arc surface, the second arc surface and the third arc surface are distributed in sequence along the direction from the first surface 11 to the second surface 12, and the radius of the second arc surface is greater than the radius of the first arc surface, and the radius of the third arc surface is greater than the radius of the second arc surface. Among them, the first arc segment line i1 rotates around the dotted line to form the first arc surface, the second arc segment line i2 rotates around the dotted line to form the second arc surface, and the third arc segment line i3 rotates around the dotted line to form the third arc surface. Each blade 2 is connected to the third arc surface and extends to the second arc surface. This embodiment uses three arcs to improve the smoothness of the air intake of the hub 1. Compared with the traditional chamfered hub 1, the aerodynamic efficiency of the fan can be improved by 1% to 2%. At the same time, each blade 2 is connected to the third arc surface and extends to the second arc surface, which can improve the smoothness of the impeller air intake and prevent the formation of vortices and gas flow separation at the blade root.

[0046] Reference Figure 8 As shown, the hub ratio refers to the ratio of the hub diameter D0 to the fan impeller diameter D. In some embodiments, the ratio of the hub diameter to the fan impeller diameter ranges from 0.45 to 0.47. Specifically, it can be calculated by the formula First calculate the specific speed n s , and then obtain a recommended hub ratio range by referring to the design manual, and then correct it through simulation and experiment to obtain the hub ratio range of this embodiment. Among them, Qv0 is the design flow rate, Pv0 is the design static pressure, n is the fan design speed, D is the fan impeller diameter, and D0 is the hub 1 diameter.

[0047] Continue to refer to Figure 8 As shown, in some embodiments, the formula Calculate the diameter of each airfoil section, where D is the fan impeller diameter, D0 is the hub diameter, N is the number of airfoil sections, i is the arrangement sequence of the airfoil sections (for example, i can be 1, 2, 3, 4...N), and the diameter of the airfoil section refers to the diameter of the circle formed by the airfoil section rotating around the hub 1, for example Figure 8 The d3 in is the diameter of the third airfoil section. In order to take into account both computational efficiency and practical results, five airfoil sections can be used for illustration.

[0048] Reference Fig. 9As shown, the airfoil section usually has parameters such as inner chord, installation angle β, chord length L, mid-arc C, camber range, camber position, and airfoil thickness. Among them, the inner chord refers to the line segment between the front and rear end points of the airfoil section, the installation angle β refers to the angle between the inner chord and the lower forehead line, the chord length L refers to the length of the inner chord, the camber refers to the ratio of the maximum distance f from the mid-arc line to the inner chord of the airfoil to the chord length L, and the camber position refers to the ratio of the distance x from the tail end of the airfoil to the position of the maximum distance from the mid-arc line to the inner chord of the airfoil to the chord length L along the inner chord direction of the airfoil.

[0049] In some embodiments, the installation angle β of the airfoil section may be: 22.5°≤β≤37.8°. For example, the installation angle β of different airfoil sections may range from 24.3° to 26.3°, 22.5° to 24.5°, 24.4° to 26.4°, 29.8° to 31.8°, 35.8° to 37.8°, etc.

[0050] In some embodiments, the chord length L of the airfoil section may be: 0.23D≤L≤0.40D, where D is the diameter of the fan impeller. For example, the chord length L of different airfoil sections may be 0.38D-0.40D, 0.364D-0.384D, 0.32D-0.34D, 0.27D-0.29D, 0.23D-0.25D, etc.

[0051] In some embodiments, the range of crown is: The camber position is: Exemplarily, the camber ranges of different airfoil cross sections may be 0.0075-0.0095, 0.024-0.026, 0.036-0.038, 0.046-0.048, 0.067-0.069, etc., and the camber positions of different airfoil cross sections may be 0.4, 0.5, 0.6, etc.

[0052] In some embodiments, the airfoil thickness S of the airfoil section is: 3.5% L≤S≤13% L. Exemplarily, the airfoil thickness S of different airfoil sections can be 3.5L%~5.5%L, 6%L~8%L, 8%L~10%L, 9%L~10%L, 11%L~13%L, etc. Fig.10 shown.

[0053] The present application solves the problem of low efficiency and high noise of the axial flow fan with blade support structure by improving the design of key shape parameters. Referring to Table 1, Table 1 is the test data of the fan impeller of the present application. It should be noted that the air density of this test is 1.205kg / m 3 data.

[0054] Static Pressure Air volume Speed Input Power Static pressure efficiency Wind rotor efficiency Pa CMH RPM Watt ％ ％ 497.53 0.00 3442 141.71 0.00 0.00 439.99 135.36 3619 142.19 11.63 13.69 380.21 289.69 3682 136.41 22.43 26.39 296.88 436.78 3682 117.61 30.63 36.03 225.29 577.87 3682 92.25 39.20 46.12 247.84 734.97 3682 101.43 49.89 58.69 207.81 884.67 3680 97.08 52.60 61.89 186.09 907.29 3680 93.70 50.05 58.89 107.79 1018.99 3680 79.21 38.52 45.32 1.86 1167.34 3681 54.58 1.11 1.30

[0055] Table 1 Test data of fan impeller

[0056] Correspondingly, the present application also provides an axial flow fan, which includes a fan impeller according to any of the above embodiments.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application is described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A fan impeller, characterized in that: include: Wheel hub; A plurality of blades, wherein the plurality of blades are respectively connected to the hub and are spaced apart along the circumference of the hub, and the stacking line of each blade has an outer curvature protruding toward the rotation direction of the blade and an inner curvature protruding toward the wind inlet side of the blade, and the distance between the outer curvature and the blade root is 0.75W to 0.85W, and the distance between the inner curvature and the blade root is 0.15W to 0.25W; The stacking line is defined as a high-order spline curve formed by sequentially connecting the airfoil centroid points of each airfoil section of the blade from the root position of the blade to the blade tip, and W is the distance from the root to the blade tip of the blade.

2. The fan impeller according to claim 1, characterized in that: The offset range of the stacking line relative to the reference line in the circumferential direction of the hub is -9%D to 4.5%D, and the offset range of the stacking line relative to the reference line in the axial direction of the hub is -4%D to 1.5%D; The connection point between the stacking line and the hub is defined as a reference point O, the normal line of the side surface of the hub passing through the reference point O is defined as a reference line, and D is the diameter of the fan impeller.

3. The fan impeller according to claim 1, characterized in that: The hub has a first surface, a second surface and a side surface. The first surface and the second surface are arranged opposite to each other. Two ends of the side surface are respectively connected to the first surface and the second surface. The plurality of blades are respectively connected to the side surfaces.

4. The fan impeller according to claim 3, characterized in that: The side surface includes a first curved surface, a second curved surface and a third curved surface. Along the direction from the first surface to the second surface, the first curved surface, the second curved surface and the third curved surface are distributed in sequence, and the radius of the second curved surface is greater than the radius of the first curved surface, and the radius of the third curved surface is greater than the radius of the second curved surface.

5. The fan impeller according to claim 4, characterized in that: The blade is connected to the third arcuate surface and extends to the second arcuate surface.

6. The fan impeller according to claim 1, characterized in that: The ratio of the hub diameter to the fan impeller diameter ranges from 0.45 to 0.

47.

7. The fan impeller according to claim 1, characterized in that: The value of the installation angle β of the airfoil section is 22.5° to 37.8°.

8. The fan impeller according to claim 1, characterized in that: The chord length L of the airfoil section is 0.23D to 0.40D, wherein D is the diameter of the fan impeller.

9. The fan impeller according to claim 1, characterized in that: The airfoil thickness S of the airfoil section is 3.5%L to 13%L, wherein L is the chord length of the airfoil section.

10. The fan impeller according to claim 1, characterized in that: The camber range of the airfoil section is 0.0075-0.069, and the camber position of the airfoil section is 0.4-0.

6.

11. An axial flow fan, characterized in that: It comprises a fan impeller as claimed in any one of claims 1 to 10.

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