Axial flow fan blade, axial flow fan and air conditioner

Abstract

The present application provides an axial flow impeller, an axial flow fan and an air conditioner. The axial flow impeller includes blades and a hub. A plurality of blades are arranged at intervals along the circumferential direction of the hub. Each blade includes a leading edge, an outer edge, a trailing edge and an inner edge. The trailing edge includes connecting lines AB, BE, EC and CD connected end to end in sequence. It is assumed that the plane passing through the rotation axis of the blade is the first plane. The blade is projected onto the first plane along the circumferential direction in the rotation direction of the blade to form a first contour line. On the first contour line, points A, B and C are located on the same straight line L1, and the angle between the straight line L1 and the rotation axis of the blade is θ1, where 75° ≤ θ1 ≤ 120°. The projection of the connecting line EC is a line segment, and this line segment is located on the straight line L2, where the angle between L2 and L1 is θ2, and 0° < θ2 ≤ 30°. According to the axial flow impeller of the present application, the trailing edge turbulence of the axial flow impeller can be improved and reduced, the aerodynamic noise of the impeller can be reduced, and the fan efficiency can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioning, and particularly relates to an axial flow impeller, an axial flow fan, and an air conditioner. Background Art

[0002] Axial flow impellers are widely used in air conditioning products due to their large air volume and low noise. The working efficiency of the axial flow impeller and the air duct in the air conditioner has an important impact on the air conditioning capacity, energy efficiency, and comfort. A low air volume of the impeller will cause poor heat exchange on the heat exchanger side of the air conditioner, reducing the heat exchange capacity of the air conditioner and increasing the system power on the refrigerant side. At the same time, a low impeller efficiency results in a high input power of the fan, increasing the fan energy consumption. Therefore, the air volume and efficiency of the axial flow impeller and the air duct in the air conditioner have an obvious impact on the performance of the air conditioner.

[0003] Generally, when the axial flow impeller works, the axial flow impeller rotates under the driving force, causing the air flow to flow axially. Due to the action of the rotating centrifugal force, the change of the pressure gradient in the radial direction, and the influence of the guiding structure in the air duct, the air flow flows radially inward or radially outward. At the trailing edge and the outer edge of the axial flow impeller, the air flow in the radial direction interferes, affecting the fan efficiency. The turbulence generated by this disturbance is relatively large, easily generating noise and affecting comfort. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present application is to provide an axial flow impeller, an axial flow fan, and an air conditioner, which can improve and reduce the trailing edge turbulence of the axial flow impeller, reduce the aerodynamic noise of the impeller, and improve the fan efficiency.

[0005] To solve the above problems, the present application provides an axial flow impeller, including blades and a hub. A plurality of blades are arranged at intervals along the circumferential direction of the hub. The blade includes a leading edge, an outer edge, a trailing edge, and an inner edge. The inner edge of the blade is fixedly connected to the hub. The inner edge intersects the leading edge at point G, the inner edge intersects the trailing edge at point D, the outer edge intersects the leading edge at point F, and the outer edge intersects the trailing edge at point A. The trailing edge includes connecting lines AB, BE, EC, and CD connected end to end in sequence;

[0006] It is assumed that the plane passing through the rotation axis of the blade is the first plane. The blade projects circumferentially along the rotation direction of the blade onto the first plane to form a first contour line. On the first contour line, points A, B, and C are located on the same straight line L1. The straight line L1 forms an angle θ1 with the rotation axis of the blade, and 75° ≤ θ1 ≤ 120°;

[0007] The projection of the connecting line EC is a line segment, and this line segment is located on the straight line L2, where the angle between L2 and L1 is θ2, and 0° < θ2 ≤ 30°.

[0008] Preferably, a plane perpendicular to the rotation axis of the blade is defined as the second plane. The blade is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the central angle formed by the connecting lines of point B, point E located on the trailing edge and the projection point O of the rotation axis is θ3, where 0 < θ3 ≤ 15°. Along the rotation direction of the blade, point E is located on the front side of point B.

[0009] Preferably, a plane perpendicular to the rotation axis of the blade is defined as the second plane. The blade is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the central angle formed by the connecting lines of point F, point G located on the leading edge and the projection point O of the rotation axis is θ4, where 15° ≤ θ4 ≤ 55°. Along the rotation direction of the blade, point F is located on the front side of point G.

[0010] Preferably, a plane perpendicular to the rotation axis of the blade is defined as the second plane. The blade is projected onto the second plane along the rotation axis to form a second contour line. At the corresponding position of point A on the second contour line, the blade height is r A , and at the corresponding position of point B, the blade height is r B , and at the corresponding position of point C, the blade height is r C ; at the corresponding position of point D, the blade height is r D , and at the corresponding position of point E, the blade height is r E , where

[0011] r A > r B ≥ r E > r C ≥ r D .

[0012] Preferably, 0.15 ≤ (r A - r B ) / (r A - r D ) ≤ 0.5.

[0013] Preferably, a plane perpendicular to the rotation axis of the blade is defined as the second plane. The blade is projected onto the second plane along the rotation axis to form a second contour line. At the corresponding position of point A on the second contour line, the blade height is r A , and at the corresponding position of point F, the blade height is r F , r A = r F .

[0014] According to another aspect of the present application, an axial flow fan is provided, including an axial flow blade, and the axial flow blade is the above-mentioned axial flow blade.

[0015] According to another aspect of the present application, an air conditioner is provided, including the above-mentioned axial flow blade or the above-mentioned axial flow fan.

[0016] The axial-flow fan blade provided by the present application includes blades and a hub. A plurality of blades are arranged at intervals along the circumferential direction of the hub. Each blade includes a leading edge, an outer edge, a trailing edge, and an inner edge. The inner edge of the blade is fixedly connected to the hub. The inner edge intersects the leading edge at point G, the inner edge intersects the trailing edge at point D, the outer edge intersects the leading edge at point F, and the outer edge intersects the trailing edge at point A. The trailing edge includes connecting lines AB, BE, EC, and CD that are sequentially connected end to end. A plane passing through the rotation axis of the blade is defined as the first plane. When the blade is projected onto the first plane along the circumferential direction in the rotation direction of the blade, a first contour line is formed. On the first contour line, points A, B, and C are located on the same straight line L1. The angle between the straight line L1 and the rotation axis of the blade is θ1, and 75° ≤ θ1 ≤ 120°. The projection of the connecting line EC is a line segment, and this line segment is located on the straight line L2, where the angle between L2 and L1 is θ2, and 0° < θ2 ≤ 30°. For the axial-flow fan blade provided by the present application, the structure of the trailing edge of the blade is improved, and the structural shape of the trailing edge of the blade is improved. The air flow passes through the fan blade channel and flows out from the trailing edge of the blade. The setting of the end points of the curve formed by the trailing edge makes the axial position of the air flow flowing out of the fan blade channel more reasonable in cooperation with the blade profile. In the curve AB, the fan blade is matched with the guiding structure to reduce the tip leakage loss of the fan blade. In the curves BE and EC, when the air flow flows out radially from the fan blade channel, it first detaches from the fan blade channel at point E, cutting off the continuous flow of the air flow towards the outer edge of the blade, reducing the flow rate of the air flow flowing from the radial direction of the blade to the tip, thereby reducing the intensity of the tip vortex, improving and reducing the trailing-edge turbulence of the axial-flow fan blade, reducing the aerodynamic noise of the fan blade, and improving the efficiency of the fan. Description of the Drawings

[0017] Figure 1 is the projection structure diagram of the axial-flow fan blade of the embodiment of the present application on the first plane;

[0018] Figure 2 is the projection structure diagram of the axial-flow fan blade of the embodiment of the present application on the second plane;

[0019] Figure 3 is the projection size diagram of the axial-flow fan blade of the embodiment of the present application on the second plane;

[0020] Figure 4 is the structure diagram of the axial-flow fan blade of the embodiment of the present application;

[0021] Figure 5 is the side view structure diagram of the axial-flow fan blade of the embodiment of the present application;

[0022] Figure 6 is the top view structure diagram of the axial-flow fan blade of the embodiment of the present application;

[0023] Figure 7 is the air flow diagram on the blade surface in the axial direction of the axial-flow fan blade of the embodiment of the present application;

[0024] Figure 8 is the airflow flow diagram on the blade surface in the circumferential direction of the axial flow fan blade in the embodiment of the present application;

[0025] Figure 9 is the comparison diagram of the relationship curves of the fan air volume and fan power between the axial flow fan of the prior art and the axial flow fan of the present application;

[0026] Figure 10 is the comparison diagram of the relationship curves of the fan air volume and fan noise between the axial flow fan of the prior art and the axial flow fan of the present application;

[0027] Figure 11 is the schematic diagram of the airflow on the surface of the axial flow fan blade of the prior art;

[0028] Figure 12 is the schematic diagram of the airflow on the surface of the axial flow fan blade of the present application;

[0029] Figure 13 is the surface pressure distribution diagram of the axial flow fan blade of the prior art;

[0030] Figure 14 is the surface pressure distribution diagram of the axial flow fan blade of the present application.

[0031] The reference signs are shown as:

[0032] 1. Blade; 11. Leading edge; 12. Outer edge; 13. Trailing edge; 14. Inner edge; 2. Hub. Detailed implementation manners

[0033] With reference to Figures 1 to 10 As shown, according to the embodiment of the present application, the axial flow fan blade includes a blade 1 and a hub 2. A plurality of blades 1 are arranged at intervals along the circumferential direction of the hub 2. The blade 1 includes a leading edge 11, an outer edge 12, a trailing edge 13 and an inner edge 14. The inner edge 14 of the blade 1 is fixedly connected to the hub 2. The inner edge 14 intersects the leading edge 11 at point G, the inner edge 14 intersects the trailing edge 13 at point D, the outer edge 12 intersects the leading edge 11 at point F, and the outer edge 12 intersects the trailing edge 13 at point A. The trailing edge 13 includes connecting lines AB, BE, EC and CD connected end to end in sequence; it is assumed that the plane passing through the rotation axis of the blade 1 is the first plane. The blade 1 is projected onto the first plane along the circumferential direction in the rotation direction of the blade 1 to form a first contour line. On the first contour line, points A, B and C are located on the same straight line L1. The angle between the straight line L1 and the rotation axis of the blade 1 is θ1, and 75° ≤ θ1 ≤ 120°; the projection of the connecting line EC is a line segment, and this line segment is located on the straight line L2, where the angle between L2 and L1 is θ2, and 0° < θ2 ≤ 30°.

[0034] For the axial flow fan blade of the present application, since the thickness of blade 1 is relatively thin, and the radius and circumferential width are relatively large, the thickness can be basically ignored compared with the radius and circumferential width of blade 1. Therefore, in order to reduce the design difficulty of blade 1, it can be assumed that blade 1 is a curved surface structure, and each edge of blade 1 is a line structure, that is, the contour line formed by the edge of blade 1 in the three-dimensional space is uniquely determined. In this embodiment, when each edge of blade 1 is a line structure, connecting lines AB, BE, EC, and CD are all curves.

[0035] During the operation of the axial flow fan, the radial air flow disturbance of the axial flow fan blade is mainly caused by the centrifugal force of the rotating air flow, the change of the pressure gradient in the radial direction, and the influence of the guiding structure in the air duct. Because the centrifugal force F = mω 2 r (m - mass; ω - rotational angular velocity; r - radius of rotation), that is, the larger the radius of rotation, the greater the centrifugal force, and the greater the pressure gradient that needs to be balanced. In order to reduce the radial air flow disturbance, the greater the radial twist of the curved surface, resulting in a more complex curved surface.

[0036] The axial flow fan blade provided by the present application improves the trailing edge structure of blade 1, improves the structural shape of the trailing edge 13 of blade 1. The air flow flows through the blade flow channel and flows out from the trailing edge 13 of blade 1. The setting of the curve endpoints formed by the trailing edge 13 makes the axial position where the air flow flows out of the blade flow channel more reasonable in cooperation with the blade profile. At curve AB, blade 1 is matched with the guiding structure to reduce the tip leakage loss of blade 1. At curve BE and curve EC, when the air flow flows out of the blade flow channel radially, the air flow detaches from the blade flow channel at point E first, cutting off the path for the air flow to continue flowing towards the outer edge of blade 1, reducing the air flow rate flowing along the radial direction of blade 1 to the blade tip, thereby reducing the intensity of the tip vortex, improving and reducing the trailing edge turbulence of the axial flow fan blade, reducing the aerodynamic noise of the blade, and improving the fan efficiency.

[0037] Set the plane perpendicular to the rotation axis of blade 1 as the second plane. Blade 1 is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the central angle formed by the connection line between point B on the trailing edge 13 and the projection point O of the rotation axis and the connection line between point E and the projection point O of the rotation axis is θ3, 0 < θ3 ≤ 15°. Along the rotation direction of blade 1, point E is located in front of point B. By limiting the position of point E relative to point B, the length of BE can be prevented from being too long, so that when the air flow flows through the blade flow channel, it will not flow out of the blade flow channel prematurely, and the loss of air flow rate can be reduced.

[0038] Set the plane perpendicular to the rotation axis of the blade 1 as the second plane. The blade 1 is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the central angle formed by the connection lines between the points F and G on the leading edge 11 and the projection point O of the rotation axis is θ4, where 15° ≤ θ4 ≤ 55°. Along the rotation direction of the blade 1, the point F is located on the front side of the point G.

[0039] Since the point F is located on the front side of the point G, and the angular difference between the points F and G in the circumferential direction is the central angle θ4, therefore, by limiting the range of θ4, it can cooperate with the structure of the trailing edge 13 to reduce the pressure gradient that needs to be balanced at the outer edge of the blade 1 and improve the air intake efficiency of the wind blade.

[0040] For an axial-flow wind blade, as the radius increases, the centrifugal force exerted on the air flow also increases, and the pressure gradient required to balance the centrifugal force needs to increase, resulting in a decrease in the radial curvature of the curved surface and an increase in the intensity of the tip vortex. Therefore, it is necessary to set the point B of the curve BE at a relatively high blade height, but the position of the point B cannot be too high, otherwise, the tip leakage increases and the air volume decreases.

[0041] In this embodiment, set the plane perpendicular to the rotation axis of the blade 1 as the second plane. The blade 1 is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the blade height corresponding to the point A is r A , the blade height corresponding to the point B is r B , the blade height corresponding to the point C is r C ; the blade height corresponding to the point D is r D , the blade height corresponding to the point E is r E , where r A > r B ≥ r E > r C ≥ r D .

[0042] Preferably, 0.15 ≤ (r A - r B ) / (r A - r D ) ≤ 0.5, which can reasonably limit the position of the point B, make the height setting of the point B in the radial direction of the blade 1 reasonable, effectively reduce the intensity of the tip vortex, and at the same time avoid an increase in tip leakage and effectively improve the air volume.

[0043] Set the plane perpendicular to the rotation axis of the blade 1 as the second plane. The blade 1 is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the blade height corresponding to the point A is r A , the blade height corresponding to the point F is r F , r A = r F .

[0044] For the above embodiments of the present application, the three-dimensional contour line of the blade 1 within the three-dimensional space corresponding to the first contour line and the second contour line is the same, and the first contour line and the second contour line are different forms projected from this three-dimensional contour line onto different planes.

[0045] Referring jointly to Figure 11 and Figure 13 As shown, for the axial-flow fan blade in the prior art, there are radial air-flow intersections and mutual disturbances on both the suction surface and the pressure surface of the blade 1. Due to the change of the operating conditions of the axial-flow fan blade, it is difficult to ensure that the centrifugal force and the radial pressure gradient are balanced everywhere. Such disturbances on the surface of the blade 1 start to form at the positions near the leading edge 11 and the inner edge 14 of the blade 1, and develop towards the outer edge 12 and the trailing edge 13 of the blade 1, becoming more intense, resulting in poorer efficiency.

[0046] Referring jointly to Figure 12 and Figure 14 As shown, after adopting the axial-flow fan blade of the present application, through this axial-flow fan blade, it is possible to reduce the area with poor efficiency in the disturbance area of the radial air flow at the trailing edge 13 of the axial-flow fan blade, thereby improving the efficiency of the fan. Through the curve EC section, the air flow successively separates from the flow channel, cutting off the path for the air flow to continue flowing towards the outer edge 12 of the blade 1, reducing the flow rate of the air flowing along the radial direction towards the blade tip of the blade 1, thereby reducing the intensity of the tip vortex and improving the efficiency of the fan blade. It can be seen from the figure that after adopting the axial-flow fan blade of the present application, the main area of the large turbulence generated by the disturbance at the trailing edge of the fan blade is significantly improved, the aerodynamic noise of the fan blade is improved, and the comfort is enhanced.

[0047] After adopting the axial-flow fan blade of the present application, taking the axial-flow fan blade formed with θ1 being 86°, θ2 being 14°, the implementation of θ3 being 4°, θ4 being 27°, and (r A -r B ) / (r A -r D ) = 0.19 as an example, the comparison of its experimental data with the axial-flow fan blade of the prior art is as Figure 9 and Figure 10 shown. It can be clearly seen from the figure that when adopting the axial-flow fan blade of the present application, under the condition of the same air volume, both the fan power and the fan noise are significantly lower than those of the axial-flow fan blade of the prior art.

[0048] According to the embodiments of the present application, the axial-flow fan includes an axial-flow fan blade, and this axial-flow fan blade is the above-mentioned axial-flow fan blade.

[0049] According to the embodiments of the present application, the air conditioner includes the above-mentioned axial-flow fan blade or the above-mentioned axial-flow fan.

[0050] It is easy for those skilled in the art to understand that, on the premise of no conflict, the above-mentioned advantageous manners can be freely combined and superimposed.

[0051] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. The above is only the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and variations can be made without departing from the technical principle of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. An axial flow fan blade, characterized in that, It includes blades (1) and a hub (2). A plurality of the blades (1) are arranged at intervals along the circumferential direction of the hub (2). The blade (1) includes a leading edge (11), an outer edge (12), a trailing edge (13) and an inner edge (14). The inner edge (14) of the blade (1) is fixedly connected to the hub (2). The inner edge (14) intersects the leading edge (11) at point G. The inner edge (14) intersects the trailing edge (13) at point D. The outer edge (12) intersects the leading edge (11) at point F. The outer edge (12) intersects the trailing edge (13) at point A. The trailing edge (13) includes connecting lines AB, BE, EC and CD connected end to end in sequence. It is set that the plane passing through the rotation axis of the blade (1) is the first plane. The blade (1) is projected onto the first plane along the circumferential direction in the rotation direction of the blade (1) to form a first contour line. On the first contour line, points A, B and C are located on the same straight line L1. The angle between the straight line L1 and the rotation axis of the blade (1) is θ1, and 75° ≤ θ1 ≤ 120°. The projection of the connecting line EC is a line segment, and this line segment is located on the straight line L2, where the angle between L2 and L1 is θ2, and 0° < θ2 ≤ 30°.

2. The axial flow fan blade according to claim 1, wherein, It is set that the plane perpendicular to the rotation axis of the blade (1) is the second plane. The blade (1) is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the central angle formed by the connecting lines of points B, E on the trailing edge (13) and the projection point O of the rotation axis is θ3, and 0 < θ3 ≤ 15°. Along the rotation direction of the blade (1), point E is located on the front side of point B.

3. The axial flow fan blade according to claim 1, characterized in that, It is set that the plane perpendicular to the rotation axis of the blade (1) is the second plane. The blade (1) is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the central angle formed by the connecting lines of points F, G on the leading edge (11) and the projection point O of the rotation axis is θ4, and 15° ≤ θ4 ≤ 55°. Along the rotation direction of the blade (1), point F is located on the front side of point G.

4. The axial flow fan blade according to claim 1, characterized in that, Set the plane perpendicular to the rotation axis of the blade (1) as the second plane. The blade (1) projects onto the second plane along the rotation axis to form a second contour line. On the second contour line, the blade height corresponding to point A is r A , the blade height corresponding to point B is r B , the blade height corresponding to point C is r C ; the blade height corresponding to point D is r D , the blade height corresponding to point E is r E , where r A ＞r B ≥r E ＞r C ≥r D 。 5. The axial-flow fan blade according to claim 4, wherein 0.15≤(r A -r B ) / (r A -r D )≤0.5。 6. The axial flow fan blade according to claim 1, characterized in that, Set the plane perpendicular to the rotation axis of the blade (1) as the second plane. The blade (1) is projected onto the second plane along the rotation axis to form a second contour line. On the second contour line, the blade height corresponding to point A is r A , and the blade height corresponding to point F is r F , r A = r F .

7. An axial flow fan, comprising an axial flow impeller, characterized in that, The axial-flow fan blade is the axial-flow fan blade according to any one of claims 1 to 6.

8. An air conditioner, characterized in that, It includes the axial-flow fan blade according to any one of claims 1 to 6 or the axial-flow fan according to claim 7.

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