Impeller and centrifugal fan having the same

Abstract

The application provides a kind of impeller and centrifugal fan with it, belong to centrifugal fan technical field, this impeller includes front disc, middle disc, rear disc, multiple blades and hub, wherein, middle disc is between front disc and rear disc, blade passes through middle disc, one end of blade is connected to front disc and the other end is connected between rear disc, hub is installed to the inner periphery of middle disc, and multiple blades are evenly distributed along the outer periphery of hub, there is flow channel for fluid flow between two adjacent blades;Blade includes opposite suction surface and pressure surface, suction surface includes protrusion, pressure surface includes groove, the height of protrusion and the groove depth of groove are 0-0.4 times of corresponding flow channel width, and the depth of groove is less than the thickness of blade.The application can improve the uniformity of fluid flow, reduce aerodynamic noise.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal fans, and particularly to an impeller and a centrifugal fan having the same. Background Art

[0002] With the popularization of range hoods, consumers are more likely to accept range hoods with a large air volume and low operating noise. For the internal noise of a range hood, generally, it can be divided into two categories: shell structure vibration noise and aerodynamic noise. A centrifugal fan is an important part of a range hood. Especially for traditional fan blades with a smooth surface, a large number of eddies are generated inside the impeller flow passage. The generation and collapse of vortices in the impeller flow passage are one of the main sound sources of aerodynamic noise. Summary of the Invention

[0003] The purpose of the present invention is to provide an impeller, on which the protrusions and the grooves are provided, so as to improve the fluid flow uniformity and reduce the aerodynamic noise.

[0004] The purpose of the present invention is to provide a centrifugal fan.

[0005] To achieve the purpose of the present invention, the following technical solutions are adopted:

[0006] According to one aspect of the present invention, an impeller for a centrifugal fan is provided. The impeller includes:

[0007] A front disc, a middle disc and a rear disc, wherein the middle disc is located between the front disc and the rear disc;

[0008] A plurality of blades passing through the middle disc, with one end connected to the front disc and the other end connected to the rear disc. There is a flow passage for fluid to flow between adjacent two blades;

[0009] A hub installed on the inner circumference of the middle disc, and the plurality of blades are evenly distributed along the outer circumference of the hub;

[0010] Among them, the blade includes a suction surface and a pressure surface opposite to each other. The suction surface includes protrusions for improving the fluid flow uniformity, and the pressure surface includes grooves for improving the fluid flow uniformity. The height of the protrusions and the depth of the grooves are both R times the width of the corresponding flow passage, where 0 < R ≤ 0.4, and the depth of the grooves is less than the thickness of the blade.

[0011] According to an embodiment of the present invention, the protrusions are multiple, and the multiple protrusions are arranged in an array to form a protrusion array for the flow mixing of the fluid on the boundary layer of the suction surface, so as to reduce the broadband noise;

[0012] There are multiple grooves, and the multiple grooves are arranged in an array to form a groove array. The grooves are used to form eddy currents, so that the boundary layer of the pressure surface undergoes transition in advance, improving the flow uniformity.

[0013] According to an embodiment of the present invention, the longitudinal cross-section of the protrusion and the longitudinal cross-section of the groove are respectively one of a circular arc shape, a V shape, an inverted U shape, and a quadratic curve.

[0014] The protrusion array includes protrusions with a longitudinal cross-section being one or more of a circular arc shape, a V shape, an inverted U shape, and a quadratic curve, and the groove array includes grooves with a longitudinal cross-section being one or more of a circular arc shape, a V shape, an inverted U shape, and a quadratic curve.

[0015] According to an embodiment of the present invention, the number of the blades is Z, where 30 ≤ Z ≤ 100.

[0016] According to an embodiment of the present invention, the cross-section of the blade is a circular arc shape.

[0017] The inner diameter of the impeller is R1, and the outer diameter of the impeller is R2, where 0.7 ≤ R1 / R2 ≤ 0.9.

[0018] According to an embodiment of the present invention, along the direction from the inlet to the outlet of the blade, the flow channel is evenly divided into N regions, and the width of the flow channel corresponding to the protrusion is W i , i = 1, 2,..., N, the width of the flow channel at the inlet end of the blade is W1, and the width of the flow channel at the outlet end of the blade is W N , the thickness of the blade is δ, the height of the protrusion is h1, and the groove depth of the groove is h2, where h1 ∈ (0, 0.4W i , h2 ∈ (0, 0.4W i , and h2 < δ.

[0019] According to an embodiment of the present invention, when 30 ≤ Z ≤ 60 and 0.7 ≤ R1 / R2 ≤ 0.8, W1 is directly measured by the geometric construction method.

[0020] When 60 < Z ≤ 100 and 0.8 < R1 / R2 ≤ 0.9, .

[0021] According to an embodiment of the present invention, the grid pitch at the outlet of adjacent blades is f2, where

[0022] ;

[0023] ;

[0024] In the formula: R b β is the radius of the arc of the blade cross section. b2 The angle between the radius of the arc where the exit point of the blade is located and the line connecting the exit point of the blade to the center of the impeller.

[0025] According to one embodiment of the present invention, for the uniform flow channel, W1 ≈ W N ≈W i d i ∈(0, 0.4W) i In the formula, di is the height of the protrusion or the depth of the groove in the i-th region;

[0026] For the accelerated flow channel, W1 > W i >W N , In the formula: d i The height of the protrusion in the i-th region or the depth of the groove;

[0027] For the flow channel that decelerates first and then accelerates, there exists a maximum flow channel region in the middle, and the width of the maximum flow channel region is W. max Among them, W max >W1, W max >W N The height of the protrusion or the groove depth of the groove located in the maximum flow channel area is d. max , ;

[0028] The area between the inlet of the flow channel and the maximum flow channel area is the first flow channel area. The first flow channel area is divided into M equal regions along the direction from the inlet to the maximum flow channel area. The height of the protrusion or the groove depth within the first flow channel area is d. p ,in, In the formula: p = 1, 2, ..., M and M ≥ 1;

[0029] The area between the maximum flow channel region and the outlet of the flow channel is the second flow channel region. The second flow channel region is divided into F equal regions along the direction from the maximum flow channel region to the outlet of the flow channel. The height of the protrusion or the groove depth within the second flow channel region is d. q ,in, In the formula: q = 1, 2, ..., F, and F ≥ 1.

[0030] According to another aspect of the present invention, a centrifugal fan is provided, the centrifugal fan including the impeller, volute, and motor described above, wherein the motor and the impeller are both disposed within the volute, the impeller is connected to the output end of the motor, and the motor is used to drive the rotation of the impeller.

[0031] One embodiment of the present invention has the following advantages or beneficial effects:

[0032] The impeller and centrifugal fan of the present invention improve fluid flow uniformity and reduce aerodynamic noise by providing the protrusions and grooves on the blades.

[0033] By setting the height of the protrusion and the depth of the groove, the flow state of the fan is improved, broadband noise is reduced, and the performance of the centrifugal fan is enhanced. Attached Figure Description

[0034] The above and other features and advantages of the present invention will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0035] Figure 1 This is a schematic diagram of an impeller according to an exemplary embodiment.

[0036] Figure 2 This is an exploded view of an impeller according to an exemplary embodiment.

[0037] Figure 3 This is a schematic diagram of the connection of the suction surface according to an exemplary embodiment.

[0038] Figure 4 This is a schematic diagram of a pressure surface according to an exemplary embodiment.

[0039] Figure 5 This is a cross-sectional view of an impeller according to an exemplary embodiment.

[0040] Figure 6 yes Figure 5 Enlarged view of point E in the middle.

[0041] Figure 7 This is a schematic diagram of adjacent blades according to an exemplary embodiment.

[0042] The reference numerals in the attached figures are explained as follows:

[0043] 1. Front disc; 2. Middle disc; 3. Rear disc; 4. Blade; 40. Flow channel; 41. Suction surface; 411. Protrusion; 42. Pressure surface; 421. Groove; 5. Hub; 6. Aluminum parts. Detailed Implementation

[0044] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. Like reference numerals in the figures denote like or similar structures, and thus their detailed description will be omitted.

[0045] The terms "a", "an", "the", and "said" are used to denote the presence of one or more elements / components / etc.; the terms "comprising" and "having" are used to mean an open inclusion and mean that there may be additional elements / components / etc. in addition to the listed elements / components / etc.

[0046] As Figures 1 to 7 shown, Figure 1 A schematic diagram of an impeller provided by the present invention is shown. Figure 2 An exploded view of the impeller provided by the present invention is shown. Figure 3 A connection schematic diagram of the suction surface 41 provided by the present invention is shown. Figure 4 A schematic diagram of the pressure surface 42 provided by the present invention is shown. Figure 5 A cross-sectional view of the impeller provided by the present invention is shown. Figure 6 is Figure 5 An enlarged view at E in Figure 7 A schematic diagram of adjacent blades 4 provided by the present invention is shown.

[0047] An impeller according to an embodiment of the present invention is used in a centrifugal fan. The impeller includes:

[0048] A front disc 1, a middle disc 2, and a rear disc 3, wherein the middle disc 2 is located between the front disc 1 and the rear disc 3;

[0049] A plurality of blades 4 pass through the middle disc 2, one end is connected to the front disc 1 and the other end is connected to the rear disc 3. Among them, there is a flow channel 40 for fluid to flow through between two adjacent blades 4;

[0050] A hub 5 is installed on the inner circumference of the middle disc, and a plurality of blades 4 are evenly distributed along the outer circumference of the hub 5;

[0051] Among them, the blade 4 includes an opposite suction surface 41 and a pressure surface 42. The suction surface 41 includes a protrusion 411 for improving the fluid flow uniformity, and the pressure surface 42 includes a groove 421 for improving the fluid flow uniformity. The height of the protrusion 411 and the depth of the groove 421 of the groove 421 are both R times the width of the corresponding flow channel, where 0 < R ≤ 0.4, and the depth of the groove 421 is less than the thickness of the blade 4.

[0052] In this design, the front disc 1, middle disc 2, and rear disc 3 are parallel to each other. The blades 4 have flanges at both ends to connect the front disc 1 and the rear disc 3. Multiple blades 4 are evenly distributed along the outer circumference of the hub 5, which is mounted on the inner circumference of the middle disc 2. The hub 5 and the middle disc 2 can be manufactured as a single piece. The impeller also includes an aluminum component 6, which is connected to the hub 5 by rivets. The aluminum component 6 has a through hole in its center for connecting to the motor's output. This allows the motor to drive the hub 5 and the blades 4 on its outer circumference to rotate, thereby rotating the airflow and achieving smoke extraction. In this embodiment, the front disc 1, middle disc 2, rear disc 3, hub 5, and aluminum component 6 are all existing technologies, and their structures and connection methods will not be described in detail here.

[0053] By providing a protrusion 411 on the suction surface 41 of the blade 4 and a groove 421 on the pressure surface 42 of the blade 4, the fluid within the boundary layer is mixed, and the large-scale eddies generated when the fluid passes through irregular flow channels are disrupted, thereby improving the uniformity of fluid flow. In particular, when the height of the protrusion 411 and the groove depth of the groove 421 are both 0-0.4 times the width of the corresponding flow channel, and the depth of the groove 421 is less than the thickness of the blade 4, the aerodynamic noise can be effectively reduced. In this embodiment, the height of the protrusion 411 is the height of the highest point of the protrusion 411 from the suction surface 41.

[0054] In a preferred embodiment of the present invention, there are multiple protrusions 411, wherein the multiple protrusions 411 are arranged in an array to form a protrusion array for the flow mixing of fluid on the boundary layer of the suction surface 41, so as to reduce broadband noise.

[0055] There are multiple grooves 421, which are arranged in an array to form a groove array. The grooves 421 are used to form vortices, so that the boundary layer of the pressure surface 42 will transition earlier and improve the flow uniformity.

[0056] In a preferred embodiment of the present invention, the longitudinal section of the protrusion 411 and the longitudinal section of the groove 421 are respectively one of the following: arc shape, V-shape, inverted U-shape, and quadratic curve.

[0057] The protrusion array includes protrusions 411 with longitudinal sections of one or more of the following shapes: arc, V, inverted U, and quadratic curve; the groove array includes grooves 421 with longitudinal sections of one or more of the following shapes: arc, V, inverted U, and quadratic curve.

[0058] As shown in Figure 3-4, multiple protrusions 411 can form an array of protrusions with equal or unequal row spacing on the suction surface 41 of the blade 4, and multiple grooves 412 can form an array of grooves with equal or unequal row spacing on the pressure surface 42 of the blade 4. The protrusions 411 and grooves 412 on the same cross section of the blade 4 can be arranged in a one-to-one correspondence or staggered arrangement. When the thickness of the blade 4 is less than 1.5 mm, the protrusions 411 and grooves 412 can be arranged in a one-to-one correspondence to facilitate the processing of the blade 4. Furthermore, the longitudinal sections of the protrusions 411 and grooves 421 are arc-shaped, V-shaped, inverted U-shaped, or quadratic curves. The grooves allow the flow to form a vortex structure within the grooves, which helps to increase the turbulent kinetic energy level of the boundary layer, causing the boundary layer to transition earlier. This helps to disrupt the large-scale vortex structure generated when the wind turbine flow passes through irregular flow channels, improving flow uniformity.

[0059] Meanwhile, the raised array can generate the effect of a vortex generator, mixing the flow within the boundary layer and transferring energy to the boundary layer fluid in the adverse pressure gradient. This allows the fluid to gain additional energy and continue to adhere to the blade surface without flow separation, thereby improving the fan flow state, reducing broadband noise, and enhancing the performance of the centrifugal fan.

[0060] In a preferred embodiment of the present invention, the number of blades 4 is Z, wherein 30≤Z≤100;

[0061] The blade 4 has a circular arc cross-section; the inner diameter of the impeller is R1, and the outer diameter of the impeller is R2, where 0.7≤R1 / R2≤0.9.

[0062] like Figure 1-6 As shown, the cross-section of blade 4 is an arc shape, but it can also be a quadratic curve or other curves. This embodiment uses an arc-shaped cross-section of blade 4 for example and illustration. When the number of blades 4 is 30-100, 0.7≤R1 / R2≤0.9, which can cause a certain disturbance to the airflow in the boundary layer, improve the uniformity of the fluid flow channel, reduce airflow separation, and prevent the generation of vortices between adjacent blades, thereby improving the aerodynamic performance of the impeller, reducing aerodynamic noise, and thus improving the aerodynamic performance of the centrifugal fan. In this embodiment, the cross-section refers to the section on blade 4 that is parallel to the front plate 1.

[0063] In a preferred embodiment of the present invention, the flow channel 40 is divided into N equal regions along the inlet-to-outlet direction of the blade 4, wherein the width of the flow channel 40 corresponding to the protrusion 411 is W. i Let i = 1, 2, ..., N, and the width of the flow channel 40 at the inlet end of blade 4 be W1, and the width of the flow channel 40 at the outlet end of blade 4 be W. N, the thickness of the blade 1 is δ, the height of the protrusion 411 is h1, and the depth of the groove 421 is h2, where h1 ∈ [0, 0.4W i ), h2 ∈ [0, 0.4W i ) and h2 < δ.

[0064] As Figure 1-7 shown, the flow channel 40 is evenly divided into N regions, and the width of the flow channel corresponding to the region of the protrusion 411 or the groove 421 is W i , in order to avoid the protrusion 411 blocking the flow channel 40 or the groove 421 affecting the flow of the fluid, in this implementation, it is found that the height of the protrusion 411 is h1 and the depth of the groove 421 is h2, where the height h1 of the protrusion 411 ∈ (0, 0.4W i , h2 ∈ (0, 0.4W i , and h2 < δ, where i = 1, 2,..., N. For different regions W i the value of can be directly measured as W1 by geometric construction, or can be determined by modeling or establishing a function of the cross-section of the blade 4.

[0065] In a preferred embodiment of the present invention, when 30 ≤ Z ≤ 60 and 0.7 ≤ R1 / R2 ≤ 0.8, W1 is directly measured by geometric construction;

[0066] When 60 < Z ≤ 100 and 0.8 < R1 / R2 ≤ 0.9, .

[0067] As Figure 5-6 shown, when 30 ≤ Z ≤ 60 and 0.7 ≤ R1 / R2 ≤ 0.8, the flow channel width W1 at the inlet of the flow channel 40 can be directly measured by geometric construction, which is a prior art in this field and will not be elaborated here. When 60 < Z ≤ 100 and 0.8 < R1 / R2 ≤ 0.9, the following approximate algorithm can be used. Assume that the inlet points of adjacent blades 4 are A and B respectively, then the pitch at the inlet of the blade 4 is f1, where, , as the number of blades 4 increases, the angle between the inlet flow channel width and the pitch tends to 0, and then the inlet width W1 of the flow channel 40 is calculated.

[0068] In a preferred embodiment of the present invention, the pitch at the outlet of adjacent blades 4 is f2, where,

[0069] ;

[0070] ;

[0071] In the formula: R b is the arc radius of the cross-section of the blade 4, β b2It is the angle between the radius of the arc where the exit point of blade 4 is located and the line connecting the exit point of blade 4 to the center of the impeller.

[0072] like Figure 7 As shown, in this embodiment, the cross-section of blade 4 is arc-shaped. In this embodiment, the cross-section refers to the section on blade 4 that is parallel to the front disk 1. By establishing the above formula, and using the angle between the radius of the arc where the exit point is located on the cross-section of blade 4 and the line connecting the exit point and the impeller center, the width of the outlet end of the flow channel 40 can be quickly calculated through modeling or the above function. .

[0073] In a preferred embodiment of the present invention, for a uniform flow channel 40, W1≈W N ≈W i d i ∈(0, 0.4 W) i In the formula: d i The height of the protrusion 411 or the groove depth of the groove 421 in the i-th region;

[0074] For the accelerated flow channel 40, W1 > W i >W N , In the formula: d i The height of the protrusion 411 or the groove depth of the groove 421 in the i-th region;

[0075] For the flow channel 40, which decelerates first and then accelerates, there is a maximum flow channel region in the middle, and the width of the maximum flow channel region is W. max Among them, W max >W1, W max >W N The height of the protrusion 411 or the groove depth of the groove 421 located in the maximum flow channel area is d. max , ;

[0076] The area between the inlet of flow channel 40 and the maximum flow channel area is the first flow channel area. The first flow channel area is divided into M equal regions along the direction from the inlet of flow channel 40 to the maximum flow channel area. The height of the protrusion 411 or the groove depth of the groove 421 in the first flow channel area is d. p ,in, In the formula: p = 1, 2, ..., M and M ≥ 1;

[0077] The area between the maximum flow channel region and the outlet of flow channel 40 is the second flow channel region. The second flow channel region is divided into F equal areas along the direction from the maximum flow channel region to the outlet of flow channel 40. The height of the protrusion 411 or the groove depth of the groove 421 within the second flow channel region is d. q ,in, In the formula: q = 1, 2, ..., F, and F ≥ 1.

[0078] like Figure 1-7 As shown in this embodiment, for different types of flow channels 40, the height of the protrusion 411 or the groove depth of the groove 421 in different areas and the width of the corresponding flow channel 40 are limited.

[0079] When flow channel 40 is a uniform velocity flow channel, then W1≈W N ≈W i d i ∈[0~0.4 W i Since the width of the flow channel 40 is much greater than 1.5 times the thickness of the blade 4, it is recommended that 0.3δ < d. i <0.2 W i ;

[0080] When flow channel 40 is an acceleration flow channel, W1 > W i >W N , In the formula: d i Let N be the height of the protrusion 411 or the groove depth of the groove 421 in the i-th region; it is recommended that 3 ≤ N ≤ 6; when the unfolded width of the blade 4 is small, such as less than 25 mm, then N = 1.

[0081] When the flow channel 40 is a flow channel that decelerates first and then accelerates, it is recommended that 3≤M≤6 and 3≤F≤6; when the blade unfolding width is small, less than 25mm, M=1 and F=1 can be used.

[0082] The protrusions 411 or grooves 421 within the aforementioned range can disturb the boundary layer fluid, improve the uniformity of fluid flow, reduce aerodynamic noise, and thus enhance the aerodynamic performance of the centrifugal fan.

[0083] The centrifugal fan of this invention includes: an impeller, a volute, and a motor as described above, wherein the motor and the impeller are both disposed inside the volute, and the impeller is connected to the output end of the motor for driving the rotation of the impeller.

[0084] The centrifugal fan can quickly extract and exhaust the exhaust gas from the stove and the fumes generated during cooking outdoors. The centrifugal fan in this embodiment includes any of the impellers described above. Since the impellers have the aforementioned technical effects, the range hood with the aforementioned impellers should also have the same technical effects.

[0085] In this embodiment of the invention, the term "multiple" refers to two or more, unless otherwise explicitly defined. The terms "install," "connect," and "fix" should be interpreted broadly. For example, "connect" can mean a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention based on the specific circumstances.

[0086] In the description of the embodiments of the present invention, it should be understood that the terms "upper" and "lower" 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 the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or unit 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 the embodiments of the present invention.

[0087] In the description of this specification, the terms "an embodiment," "a preferred embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which 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.

[0088] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. For those skilled in the art, the embodiments of the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention.

Claims

1. An impeller for a centrifugal fan, characterized in that, Comprising: A front disk (1), a middle disk (2) and a rear disk (3), wherein the middle disk (2) is located between the front disk (1) and the rear disk (3); A plurality of blades (4) passing through the middle disk (2), with one end connected to the front disk (1) and the other end connected to the rear disk (3), wherein there is a flow passage (40) for fluid to flow through between two adjacent blades (4); A hub (5) installed on the inner circumference of the middle disk, and the plurality of blades (4) are evenly distributed along the outer circumference of the hub (5); Wherein, the blade (4) includes an opposite suction surface (41) and pressure surface (42), the suction surface (41) includes a protrusion (411) for improving the fluid flow uniformity, the pressure surface (42) includes a groove (421) for improving the fluid flow uniformity, the height of the protrusion (411) and the groove depth of the groove (421) are both R times the width of the corresponding flow passage, wherein 0 < R ≤ 0.4, and the depth of the groove (421) is less than the thickness of the blade (4); Along the inlet to outlet direction of the blade (4), the flow channel (40) is divided into N equal regions, and the width of the flow channel (40) corresponding to the protrusion (411) is W. i , i=1,2,…,N, the width of the flow channel (40) at the inlet end of the blade (4) is W1, and the width of the flow channel (40) at the outlet end of the blade (4) is W N The thickness of the blade (4) is δ, the height of the protrusion (411) is h1, and the groove depth of the groove (421) is h2, where h1∈(0, 0.4 W) i ],h2∈(0,0.4 W i ], and h2 < δ; The pitch at the outlet of adjacent blades (4) is f2, wherein, ； ； In the formula: R b β is the radius of the arc of the cross section of the blade (4). b2 R2 is the angle between the radius of the arc where the exit point of the blade (4) is located and the line connecting the exit point of the blade (4) to the center of the impeller; the outer diameter of the impeller is R2, and the number of blades (4) is Z, where 30≤Z≤100; For the uniform flow channel (40), W1≈W N ≈W i d i ∈(0, 0.4 W) i In the formula: d i The height of the protrusion (411) or the depth of the groove (421) in the i-th region; For the accelerated flow channel (40), W1 > W i >W N , In the formula: d i The height of the protrusion (411) in the i-th region or the groove depth of the groove (421); For the flow channel (40) that decelerates first and then accelerates, there is a maximum flow channel region in the middle, and the width of the maximum flow channel region is W. max Among them, W max >W1, W max >W N The height of the protrusion (411) located in the maximum flow channel area or the groove depth of the groove (421) is d. max , ; The area between the inlet of the flow channel (40) and the maximum flow channel area is the first flow channel area. The first flow channel area is divided into M equal regions along the direction from the inlet of the flow channel (40) to the maximum flow channel area. The height of the protrusion (411) or the groove depth of the groove (421) in the first flow channel area is d. p ,in, In the formula: p = 1, 2, ..., M and M ≥ 1; The area between the maximum flow channel area and the outlet of the flow channel (40) is the second flow channel area. The second flow channel area is divided into F equal regions along the direction from the maximum flow channel area to the outlet of the flow channel (40). The height of the protrusion (411) or the groove depth of the groove (421) in the second flow channel area is d. q ,in In the formula: q = 1, 2, ..., F, and F ≥ 1.

2. The impeller according to claim 1, characterized in that, There are a plurality of the protrusions (411), wherein the plurality of protrusions (411) are arranged in an array to form a protrusion array for the flow mixing of the fluid on the boundary layer of the suction surface (41) to reduce broadband noise; There are a plurality of the grooves (421), wherein the plurality of grooves (421) are arranged in an array to form a groove array, and the grooves (421) are used to form eddy currents, so that the boundary layer of the pressure surface (42) undergoes transition in advance to improve the flow uniformity.

3. The impeller according to claim 2, characterized in that, The longitudinal section of the protrusion (411) and the longitudinal section of the groove (421) are respectively one of a circular arc, V-shaped, inverted U-shaped, and quadratic curve; The protrusion array includes protrusions (411) with a longitudinal section being one or more of a circular arc, V-shaped, inverted U-shaped, and quadratic curve, and the groove array includes grooves (421) with a longitudinal section being one or more of a circular arc, V-shaped, inverted U-shaped, and quadratic curve.

4. The impeller according to claim 1, characterized in that, The cross-section of the blade (4) is circular arc-shaped; The inner diameter of the impeller is R1, wherein 0.7 ≤ R1 / R2 ≤ 0.

9.

5. The impeller according to claim 4, characterized in that, When 30 ≤ Z ≤ 60 and 0.7 ≤ R1 / R2 ≤ 0.8, directly measure W1 by geometric construction method; When 60 < Z ≤ 100 and 0.8 < R1 / R2 ≤ 0.9, .

6. A centrifugal fan, characterized in that, Comprising an impeller, a volute and a motor as described in any one of claims 1-5, wherein the motor and the impeller are both arranged in the volute, the impeller is connected to the output end of the motor, and the motor is used to drive the rotation of the impeller.

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