Backward centrifugal wave-shaped blade, backward centrifugal fan blade and centrifugal fan

Abstract

The utility model relates to a backward centrifugal wave-shaped blade, a backward centrifugal fan blade and a centrifugal fan, the backward centrifugal wave-shaped blade comprises a blade main body, and the blade main body is of a wave-shaped structure arranged along the axial direction; the blade main body comprises an air inlet side, a chassis side and an air outlet side, the air inlet side is the front edge of the blade main body, and the air outlet side is the rear edge of the blade main body; the pressure surface of the blade on the air inlet side is a concave curved surface, the distance A from the deepest concave part to the connecting line of the two ends of the blade meets the formula: A = (2.5%-4.5%) H, and H is the height of the fan blade; the blade pressure surface on the chassis side is a convex curved surface, and the distance B from the highest convex position to the connecting line of the two ends of the blade meets the formula: B = (1.5%-3.5%) H; the front edge is provided with a protruding structure, and the distance T between the highest protruding position of the protruding structure and the connecting line of the two ends of the blade meets the condition that T = (2.0%-5.5%) H. The scheme has the advantages that the air inlet efficiency is improved, the airflow stability is improved, the structural strength is enhanced, and noise is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to air conditioning equipment air supply system field especially relates to a backward centrifugal wave shape blade, backward centrifugal fan blade and centrifugal fan. BACKGROUND

[0002] Centrifugal fan blade is the core component of air conditioning equipment to realize high -efficient air supply, and its blade profile design directly influences air volume, noise and running stability. The prior art such as patent CN201820708587.5 discloses "single curvature or equal thickness straight blade structure", although simple processing, but there are many key defects, seriously restrict the performance improvement of centrifugal fan. First, the air inlet efficiency of the existing straight blade structure is low. Since the curvature of the pressure surface is single, the airflow cannot fully diffuse at the air inlet side, resulting in insufficient effective air inlet volume. This directly limits the space for improving air volume, and it is difficult to meet the demand of high -efficient air supply. Secondly, the airflow stability is poor. The blade leading edge lacks effective flow guide structure, resulting in airflow concentrated impact on the blade surface. This impact will produce high-frequency pressure pulsation, and then cause significant aerodynamic noise, seriously affecting user experience and the quiet performance of the equipment. Thirdly, the existing blade has the risk of structural deformation. When the blade is axially stressed, due to the lack of curvature compensation design, local deformation is prone to occur due to the action of centrifugal force. Such deformation not only affects the dynamic balance of the blade, but also may cause the efficiency of the fan to decrease, and even cause safety hazards.

[0003] These problems seriously restrict the performance improvement of centrifugal fan, and it is difficult to meet the requirements of modern air conditioning equipment for high efficiency, low noise and stable operation. Therefore, it is of great significance to develop a new type of blade structure that can comprehensively solve the above problems to improve the performance of centrifugal fan and improve user experience.

[0004] In view of the above problems, the prior art needs to be improved. SUMMARY

[0005] In order to solve the above problems, the purpose of the utility model is to provide a backward centrifugal wave shape blade, backward centrifugal fan blade and centrifugal fan, which has the advantages of improving air inlet efficiency, improving airflow stability, enhancing structural strength and reducing noise.

[0006] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0007] The application provides a backward centrifugal wave shape blade, and the technical scheme is as follows: a blade main body, the blade main body is in a wave shape structure, and the wave direction is arranged along the axial direction; the blade main body includes a leading edge and a trailing edge, the upper end of the leading edge of the blade main body is the air inlet side, the lower end of the leading edge is the bottom disc side, and the trailing edge of the blade main body is the air outlet side;

[0008] The pressure surface of the blade on the air inlet side is a concave curved surface, and the distance A from the deepest point of the concavity to the line connecting the two ends of the blade satisfies: A = (2.5%~4.5%)H, where H is the blade height; the pressure surface of the blade on the chassis side is a convex curved surface, and the distance B from the highest point of the convexity to the line connecting the two ends of the blade satisfies: B = (1.5%~3.5%)H; the leading edge is provided with a protruding structure, and the distance T from the highest point of the protrusion to the line connecting the two ends of the blade satisfies: T = (2.0%~5.5%)H.

[0009] Furthermore, this application also proposes that the distance A is 3.0% to 4.0% of the blade height H.

[0010] Furthermore, this application also proposes that the distance B is 2.0% to 3.0% of the blade height H.

[0011] Furthermore, this application also proposes that the distance T is 3.0% to 5.0% of the blade height H.

[0012] Furthermore, this application also proposes that the air outlet side is provided with a serrated structure.

[0013] Furthermore, this application also proposes that the tooth height of the serrated structure is 0.5 to 1.5 times the thickness of the air outlet side, and the tooth pitch is 2 to 4 times the tooth height.

[0014] Furthermore, this application also proposes that the axial cross-section of the wave-shaped blade is a continuous smooth curve, and that the concave air intake side and the convex chassis side form a symmetrical compensation structure.

[0015] Furthermore, this application also proposes that the outline of the leading edge protrusion structure is a tapered arc shape, with its maximum protrusion located at the front 1 / 3 of the leading edge length.

[0016] Furthermore, this application also proposes a backward centrifugal fan blade, including a circular base, an outer ring, and multiple blades; the center of the circular base forms a hub, the multiple blades are distributed circumferentially along the circular base, and the bottom of the blades are fixed to the circular base; the outer ring is connected to the top of the blades; the blades are the aforementioned backward centrifugal wave-shaped blades.

[0017] Furthermore, this application also proposes a centrifugal fan, including a volute and centrifugal fan blades disposed within the volute; the centrifugal fan blades are the aforementioned backward centrifugal fan blades.

[0018] As can be seen from the above, the present application provides a backward centrifugal wave-shaped blade, a backward centrifugal fan blade, and a centrifugal fan, including a blade body. The blade body has a wave-shaped structure, and the wave direction is arranged along the axial direction. The blade body includes an air inlet side, a chassis side, and an air outlet side, wherein the air inlet side is the leading edge of the blade body, and the air outlet side is the trailing edge of the blade body. The blade pressure surface on the air inlet side is a concave curved surface, and the distance A from the deepest point of the concavity to the line connecting the two ends of the blade satisfies: A = (2.5%~4.5%)H, where H is the height of the fan blade. The blade pressure surface on the chassis side is a convex curved surface, and the distance B from the highest point of the convexity to the line connecting the two ends of the blade satisfies: B = (1.5%~3.5%)H. The leading edge is provided with a protruding structure, and the distance T from the highest point of the protrusion to the line connecting the two ends of the blade satisfies: T = (2.0%~5.5%)H. By designing a wave-shaped structure and specific surface parameters, the air intake efficiency is improved, the airflow stability is enhanced, the structural strength is strengthened, and the noise is reduced through the sawtooth structure. It has the advantages of improving air intake efficiency, improving airflow stability, enhancing structural strength, and reducing noise. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of a backward centrifugal fan blade provided for this application.

[0020] Figure 2 This is a top view of a backward centrifugal fan blade provided in this application.

[0021] Figure 3 This application provides a cross-sectional schematic diagram of a backward centrifugal fan blade, namely... Figure 2 AA sectional view. Detailed Implementation

[0022] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0023] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not 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 utility model.

[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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.

[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] Example 1:

[0028] like Figures 1-3 As shown, this embodiment relates to a backward centrifugal wavy blade, including a blade body 1. The blade body 1 has a wavy structure, and the wave direction is arranged along the axial direction. The blade body 1 includes a leading edge 10 and a trailing edge 11. The upper end of the leading edge 10 is the air inlet side 14, the lower end of the leading edge 10 is the chassis side 13, and the trailing edge 11 is the air outlet side. The blade pressure surface 15 of the air inlet side 14 is a concave curved surface. Figure 3In this design, the back pressure surface 17 has a concave depth at a distance A from the line connecting the two ends of the blade, satisfying the condition: A = (2.5%~4.5%)H, where H is the blade height. The blade pressure surface 15 on the chassis side 13 is a convex curved surface, with the highest point of its convexity at a distance B from the line connecting the two ends of the blade, satisfying the condition: B = (1.5%~3.5%)H. The leading edge 10 has a protruding structure, with the highest point of its protrusion at a distance T from the line connecting the two ends of the blade, satisfying the condition: T = (2.0%~5.5%)H. In this design, the wave-shaped axial structure achieves coordinated control of airflow diffusion and aggregation through continuous curvature changes. The concave curved surface on the inlet side 14 increases the airflow contact area and improves the intake volume. The convex curved surface on the chassis side 13 forms a centrifugal force compensation zone, suppressing structural deformation during high-speed rotation. The protruding structure on the leading edge 10 guides the airflow through a smooth transition, reducing impact noise. Three features form an axial force balance system: the protruding part of the leading edge 10 of the blade first introduces the airflow, dispersing the airflow entering the flow channel and causing pressure concentration, reducing pressure pulsation and aerodynamic noise. Furthermore, the concave surface reduces local stress concentration, the convex surface provides reverse support force, and the protruding structure disperses the load on the leading edge 10, jointly optimizing aerodynamic performance and structural strength. Specifically, the axial section of the wave-shaped structure can be achieved using a continuous smooth curve such as a sine curve, polynomial curve, or spline curve. As a preferred embodiment, the radius of curvature of the concave surface on the air inlet side 14 can be set to 15%-25% of the blade height, and the radius of curvature of the convex surface on the chassis side 13 can be set to 20%-30% of the blade height. The contour of the protruding structure of the leading edge 10 can be a tapered arc, an elliptical arc, or a compound curve, with its maximum protrusion preferably located at the front 1 / 3 of the length of the leading edge 10. Thus, this technical solution solves the technical problems of low air inlet efficiency, poor airflow stability, and structural deformation risk of traditional centrifugal fan blades through a wave-shaped blade structure. Compared with existing technologies, the concave curved surface design of the air inlet side 14 allows for full diffusion of airflow on the air inlet side 14, effectively increasing the air intake volume; the convex curved surface of the chassis side 13 generates a reverse support force during high-speed rotation, compensating for deformation caused by centrifugal force; the protruding structure of the leading edge 10 ensures a smooth airflow transition, reducing pressure pulsation and noise caused by airflow impact. The synergistic effect of these three features achieves simultaneous optimization of aerodynamic performance and structural strength.

[0029] In a further refined scheme, distance A is 3.0% to 4.0% of the blade height H. Distance A refers to the vertical distance between the deepest point of the concave surface on the inlet side 14 and the line connecting the two ends of the blade. As a preferred embodiment, when the blade height H is 100mm, distance A is controlled within the range of 3.0-4.0mm; for different blade specifications, this parameter range is scaled proportionally. Specifically, the working principle of this technical solution is: by limiting the concave depth to a specific proportional range, the airflow forms a moderately diffused boundary layer on the inlet side 14. The lower limit of 3.0%H ensures that the airflow obtains sufficient diffusion space, avoiding airflow stripping due to insufficient concavity; the upper limit of 4.0%H prevents excessive concavity of the surface from causing localized stress concentration.

[0030] In a further refined design, the blade pressure surface 15 on the chassis side 13 adopts a convex curved surface structure, with the distance B from the highest point of the convexity to the line connecting the two ends of the blade limited to 2.0% to 3.0% of the blade height H. Thus, this technical solution precisely controls the convex curvature of the chassis side 13 within the range of 2.0% to 3.0% of H, allowing the airflow to obtain adequate diffusion space on the chassis side 13. When the airflow passes through this convex curved surface, the pressure gradient is optimized, avoiding boundary layer separation caused by insufficient curvature. Simultaneously, this curvature range effectively suppresses flow losses, working synergistically with the concave curved surface on the inlet side 14 to achieve a smooth transition of airflow within the flow channel.

[0031] In a further refined design, the protrusion height of the leading edge 10 protrusion structure is limited to 3.0%–5.0% of the blade height H. This protrusion height is determined by measuring the vertical distance T from the highest point of the protrusion to the line connecting the two ends of the blade. The lower limit of 3.0%H ensures that the protrusion structure has sufficient guiding height to effectively guide the airflow smoothly to the pressure surface and reduce airflow separation; the upper limit of 5.0%H controls the amount of protrusion to avoid excessive increase in local stress and maintain the structural integrity of the leading edge 10. Specifically, the profile of the leading edge 10 protrusion structure is a tapered arc, with the maximum protrusion position located at the front 1 / 3 of the length of the leading edge 10. The tapered arc profile refers to the curve of the protrusion structure that smoothly transitions to both sides from the maximum protrusion position, with the radius of curvature gradually decreasing. This technical solution improves airflow distribution through the synergistic effect of specific geometric features: the tapered arc profile forms a continuously changing curvature gradient, allowing the airflow to smoothly transition along the pressure surface and avoiding flow separation; the forward shift of the maximum protrusion position causes the airflow impact point to occur earlier, starting diffusion at the leading edge of the blade.

[0032] like Figure 1 and 3As shown, a serrated structure 16 is provided on the air outlet side. The tooth height of the serrated structure 16 is 0.5 to 1.5 times the thickness of the air outlet side, and the tooth pitch is 2 to 4 times the tooth height. As a preferred embodiment, the serrated structure 16 can adopt an isosceles triangular tooth shape with a tooth apex angle of 60° to 90°; or a trapezoidal tooth shape with a tooth apex width of 1 / 3 to 1 / 2 of the tooth height. Further, the serrated structure 16 can be continuously arranged along the edge of the air outlet side, or spaced out in specific noise-sensitive areas. This technical solution changes the spatial distribution of airflow separation points through the serrated structure 16, breaking the concentrated vortex into multiple small-scale vortices. Specifically, when the airflow flows through the serrated structure 16, alternating local low-pressure areas are formed at the tooth tips and tooth valleys, forcing the airflow to separate regularly between the teeth. The ratio of tooth height to air outlet side thickness ensures that the airflow separation intensity is moderate, avoiding excessive interference with the mainstream; the ratio of tooth pitch to tooth height controls the vortex breaking frequency, dispersing noise energy to a frequency band insensitive to the human ear. Therefore, while maintaining aerodynamic efficiency, discrete noise in the 2000-5000Hz frequency band is effectively suppressed. Compared with the smooth straight trailing edge 11 of the prior art, this scheme achieves a reduction in sound pressure level of broadband noise through structured eddy current control.

[0033] Furthermore, this application proposes that the axial cross-section of the corrugated blade is a continuous smooth curve, and that the concave inlet side 14 and the convex outward side 13 of the chassis side form a symmetrical compensation structure. This technical solution achieves dual improvement through the synergistic effect of fluid dynamics optimization and structural mechanical compensation. The continuous axial curvature stabilizes the development of the airflow boundary layer. Structurally, an asymmetric curvature ratio design is adopted to avoid excessive airflow diffusion while maintaining the compensation effect, ensuring that no additional vortices are generated under conditions where the airflow is increased by 8%-12%.

[0034] Example 2:

[0035] like Figures 1-3 As shown, this embodiment proposes a backward centrifugal fan blade, including a circular base 2, an outer ring 3, and multiple blades. The center of the circular base 2 forms a hub 21, and the multiple blades are distributed circumferentially along the circular base 2, with the bottom of the blades fixed to the circular base 2. The outer ring 3 is connected to the top of the blades. The blades are wavy blades as described in Embodiment 1. Thus, the backward centrifugal fan blade solves the technical problems of low air intake efficiency, poor airflow stability, and wideband noise caused by the design defects of traditional centrifugal fan blades by adopting a wavy blade structure. The circular base 2 and hub 21 form a support structure to ensure the stability of blade installation; the circumferentially distributed blades form a uniform flow channel to optimize airflow distribution; the outer ring 3 connects to the top of the blades to enhance overall rigidity. The axial wave structure of the wavy blade can improve the airflow diffusion efficiency on the air intake side 14, the protruding structure of the leading edge 10 improves airflow impact, and the serrated trailing edge 11 suppresses vortex shedding noise. The synergistic effect of these features achieves efficient and low-noise airflow delivery.

[0036] Example 3:

[0037] This embodiment discloses a centrifugal fan, including a volute and centrifugal blades disposed within the volute; the centrifugal blades are the backward-curved centrifugal blades described in Embodiment 2. Specifically, this technical solution achieves its technical effect through the synergistic cooperation of the volute and the backward-curved centrifugal blades. The spiral flow channel of the volute guides the airflow to diffuse smoothly, and in conjunction with the wave-shaped structure of the blades, the airflow forms a laminar flow state in the axial direction. The convex structure of the leading edge 10 of the blades disperses the intake air impact to the crests and troughs of the wave structure, reducing local pressure pulsation. The symmetrical compensation design of the concave inlet side 14 and the convex outward of the chassis side 13 forms a mechanical balance during high-speed rotation, suppressing blade deformation. The serrated structure 16 of the trailing edge 11 disrupts the periodicity of vortex shedding, concentrating broadband noise energy in the high-frequency band that can be absorbed by the volute.

[0038] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0039] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A backward centrifugal wavy blade, comprising a blade body (1), characterized in that: The blade body (1) has a wave-shaped structure with the wave direction set along the axial direction; the blade body (1) includes a leading edge (10) and a trailing edge (11), the upper end of the leading edge (10) of the blade body (1) is the air inlet side (14), the lower end of the leading edge (10) is the chassis side (13), and the trailing edge (11) of the blade body (1) is the air outlet side; The blade pressure surface (15) of the air inlet side (14) is a concave curved surface, and the distance A from the deepest point of its concavity to the line connecting the two ends of the blade satisfies: A = (2.5%~4.5%)H, where H is the height of the blade; The blade pressure surface (15) on the chassis side (13) is a convex curved surface, and the distance B from the highest point of its convexity to the line connecting the two ends of the blade satisfies: B = (1.5% ~ 3.5%)H; The leading edge (10) is provided with a protruding structure, and the distance T from the highest point of the protrusion to the line connecting the two ends of the blade satisfies: T = (2.0% ~ 5.5%)H.

2. The backward centrifugal wavy blade according to claim 1, characterized in that: The distance A is 3.0% to 4.0% of the wind turbine blade height H.

3. The backward centrifugal wavy blade according to claim 1, characterized in that: The distance B is 2.0% to 3.0% of the wind turbine blade height H.

4. The backward centrifugal wavy blade according to claim 1, characterized in that: The distance T is 3.0% to 5.0% of the blade height H.

5. The backward centrifugal wavy blade according to claim 1, characterized in that: The air outlet side is provided with a serrated structure (16).

6. The backward centrifugal wavy blade according to claim 5, characterized in that: The tooth height of the sawtooth structure (16) is 0.5 to 1.5 times the thickness of the air outlet side, and the tooth pitch is 2 to 4 times the tooth height.

7. The backward centrifugal wavy blade according to any one of claims 1 to 6, characterized in that: The axial cross section of the wave-shaped blade is a continuous smooth curve, and the concave air intake side (14) and the convex chassis side (13) form a symmetrical compensation structure.

8. The backward centrifugal wavy blade according to claim 1, characterized in that: The outline of the protruding structure of the leading edge (10) is a tapered arc shape, and its maximum protrusion position is located at the first 1 / 3 of the length of the leading edge (10).

9. A backward centrifugal fan blade, comprising a circular base (2), an outer ring (3), and multiple blades; the center of the circular base (2) forms a hub (21), the multiple blades are distributed circumferentially along the circular base (2), and the bottom of the blades is fixed to the circular base (2); the outer ring (3) is connected to the top of the blades; characterized in that: The blade is a backward centrifugal wavy blade as described in any one of claims 1 to 8.

10. A centrifugal fan, comprising a volute casing and centrifugal fan blades disposed within the volute casing; characterized in that: The centrifugal fan blade is the backward centrifugal fan blade as described in claim 9.

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