Blade for impeller of centrifugal fan, impeller, centrifugal fan, and extractor hood

Abstract

The application relates to the range hood field, in particular to a blade for a centrifugal fan impeller. The blade is arranged in an arc shape, and the blade has oppositely arranged front and back sides; along the height direction of the blade, the blade has oppositely arranged first and second ends; along the height direction of the blade, the front side is divided into a first section and a second section, the first section is arranged close to the first end, the second section is arranged close to the second end, and a plurality of continuous first sawteeth are arranged on the whole second section; along the height direction of the blade and from the second end to the first end, the back side is divided into at least a third section, a fourth section and a fifth section which are sequentially connected; n continuous second sawteeth are arranged on the whole fourth section, and a plurality of continuous third sawteeth are arranged on the whole fifth section. The application can increase and change the success probability of vortex shedding position while ensuring the function of the second end of the blade.

Description

Technical Field

[0001] This application relates to the field of range hoods, and in particular to a blade for a centrifugal fan impeller, an impeller, a centrifugal fan, and a range hood. Background Technology

[0002] Centrifugal fans are widely used in various household appliances such as air conditioners, range hoods, air purifiers, and exhaust fans due to their advantages such as compact structure, high pressure coefficient, large flow coefficient, and low noise. With the improvement of people's living standards and the mandatory implementation of national standards for energy conservation and noise reduction in household appliances, increasingly stringent requirements are being placed on the energy efficiency and low noise performance of centrifugal fans.

[0003] During operation, centrifugal fans experience significant gas flow separation within the impeller channels, leading to the generation of vortices. Traditional techniques utilize appropriate tooth profiles at the leading edge and trailing edge to disrupt these vortices, streamline the airflow, and stabilize it. This reduces fan performance loss and noise.

[0004] However, with serrations on both the leading and trailing edges, the work capacity of the corresponding blade tip sections is significantly reduced. Influenced by the outflow from other areas of the blades and the internal resistance of the fan, the turbulence near the impeller tip outlet intensifies, leading to increased noise. Simultaneously, after the airflow passes through the leading edge serrations, existing vortices are broken up or transformed into smaller vortices. As these smaller vortices pass through the trailing edge, the trailing edge wave shape, which originally targeted the larger vortices, becomes less effective in altering the location of these smaller vortices, resulting in unsatisfactory noise reduction. Summary of the Invention

[0005] Based on this, this application provides a first technical solution to the above-mentioned technical problems, which can rectify the flow and change the position of the wake vortex shedding while ensuring the power performance of the wind turbine, so as to reduce the noise when the blades are in use.

[0006] The first technical solution provided in this application is as follows:

[0007] A blade for a centrifugal fan impeller, wherein the blade is arc-shaped and the arc length of the blade is denoted as L. arc Along the arc extension direction of the blade, the blade has a front side and a rear side that are arranged opposite to each other, and the airflow is guided to the rear side through the front side; let the height of the blade be L1, and along the height direction of the blade, the blade has a first end and a second end that are arranged opposite to each other;

[0008] Along the height direction of the blade, the front side is configured as a first segment and a second segment. The first segment is located near the first end, and the second segment is located near the second end. The height of the second segment is denoted as L2, and multiple continuous first serrations are provided on the entire second segment.

[0009] Along the height direction of the blade and from the second end to the first end, the rear side is configured with at least a third segment, a fourth segment, and a fifth segment connected in sequence; the third segment is configured as a non-serrated segment with a height of L3, the fourth segment has a height of L4, and from the second end to the first end, the fourth segment extends from the second segment to the first segment;

[0010] The fourth segment has n consecutive second sawtooth teeth with a tooth width of t1. The fifth segment has multiple consecutive third sawtooth teeth with a tooth width of t2, where t2 > t1. L1, L2, L3, and L4 satisfy the following relationship:

[0011]

[0012] In one embodiment, the second and third saw teeth have the same height along a direction perpendicular to the blade height and are both set to h.

[0013] In one embodiment, along the height direction of the blade, from the second end to the first end, the tooth width of the n second serrations is set to t. 11 t 12 ... t 1n-1 t 1n (4≤n), and the widths of each tooth satisfy: t 1n ≤t 1n-1 ≤...≤t 12 ≤t 11 , 3h≤t1≤10h.

[0014] In one embodiment, t2 and h satisfy the relationship: 4h≤t2≤15h.

[0015] In one embodiment, h satisfies the following relationship: 0.5mm ≤ h ≤ 2.5mm.

[0016] In one embodiment, L2 and L3 satisfy the relationship: L2 / 2≤L3<L2.

[0017] In one embodiment, along the height direction of the blade, the rear side further includes a sixth segment, which is connected to the end of the fifth segment away from the fourth segment. The sixth segment is configured as a non-serrated end and extends to the end position of the first end and is configured as a straight segment.

[0018] In one embodiment, the height of the sixth segment is L6, and the height of the fifth segment is L5, where L5 and L6 satisfy the following relationship:

[0019] 0 <L6≤t2,L5=L1-L3-L4-L6。

[0020] In one embodiment, L1 and L2 satisfy the relationship: 0 < L2 < L1 / 3;

[0021] Along the direction perpendicular to the blade height, the height of the first serration is H. C 0 <H C ≤0.25*L arc .

[0022] In one embodiment, the first sawtooth is configured as an arc tooth with a radius of R, 0. <R≤0.125*L arc .

[0023] This application also provides the following technical solutions:

[0024] A centrifugal fan impeller, including the blades described above.

[0025] This application also provides the following technical solutions:

[0026] A centrifugal fan, including the blades described above.

[0027] This application also provides the following technical solutions:

[0028] A range hood includes the aforementioned blades.

[0029] Compared with existing technologies, the centrifugal fan impeller blades provided in this application achieve overall coupling and precise correlation of the relationships between L1, L2, L3, L4, and L5, so that the fourth segment 22 is positioned in the middle of the blade 100 and close to the first serration 121. This allows the fourth segment 22 to essentially comprehensively receive the airflow processed by the first serration 121, and further guide large and small vortices in the airflow through the dense toothed area, thereby dispersing the outflow from the blade 100 and increasing and changing the success rate of vortex shedding. This increases the distance between vortex centers, suppresses the disturbance of the wake flow by detached vortices, and reduces the aerodynamic noise caused by unsteady pressure pulsations on the blade 100 surface and wake vortices, thus reducing the noise during impeller operation. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the centrifugal fan impeller structure provided in this application.

[0032] Figure 2 A three-dimensional structural diagram of the blade provided in this application.

[0033] Figure 3 Provided for this application Figure 2 A top view of the middle blade structure.

[0034] Figure 4 Provided for this application Figure 2 A schematic diagram of the structure of the middle blade from one perspective.

[0035] Figure 5 Provided for this application Figure 2 Another structural diagram of the middle blade.

[0036] Figure 6 This is a schematic diagram of the structure marked with symbols on the blade provided in this application.

[0037] Reference numerals: 100, blade; 10, front side; 101, flow channel; 11, first section; 12, second section; 121, first serration; 20, rear side; 21, third section; 22, fourth section; 221, second serration; 222, projected section; 23, fifth section; 231, third serration; 24, sixth section; 30, first end; 40, second end; 200, impeller. Detailed Implementation

[0038] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0039] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0041] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is 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 can mean that the first feature is 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.

[0042] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0043] like Figure 1 As shown, this application provides a blade 100 for a centrifugal fan impeller (hereinafter referred to as blade 100). Blade 100 is mainly used on the impeller 200 of a centrifugal fan, especially a multi-blade centrifugal fan.

[0044] like Figures 2 to 6 As shown, the blade 100 is set to be arc-shaped and the arc length of the blade 100 is denoted as L. arc Extending along the arc of blade 100 (i.e., the arc length direction of blade 100, such as...) Figure 3In the X direction (as shown in the image), the blade 100 has a front side 10 and a rear side 20 arranged opposite to each other. When the centrifugal fan is working, the airflow is guided through the front side 10 to or flows to the rear side 20; let the height of the blade 100 be L1, along the height direction of the blade 100 (e.g., ... Figure 4 In the Y direction of the blade, the blade 100 has a first end 30 and a second end 40 disposed opposite to each other; along the height direction of the blade 100, the front side 10 is configured as a first segment 11 and a second segment 12, the first segment 11 is disposed near the first end 30, and the second segment 12 is disposed near the second end 40, the height of the second segment 12 is denoted as L2, and a plurality of continuous first serrations 121 are provided on the entire second segment 12; along the height direction of the blade 100 and from the second end 40 to the first end 30, the rear side 20 is configured as at least a third segment 21, a fourth segment 22 and a fifth segment connected in sequence. 23; The third segment 21 is set as a non-serrated segment with a height of L3; the fourth segment 22 has a height of L4 and extends from the second end 40 to the first end 30, from the second segment 12 to the first segment 11; the fifth segment 23 has a height of L5; n consecutive second serrations 221 are set on the entire fourth segment 22 with a tooth width of t1; multiple consecutive third serrations 231 are set on the entire fifth segment 23 with a tooth width of t2, where t2 > t1; L1, L2, L3, L4 and L5 satisfy the following relationship: And L3 < L2, L5 < L1 - L2.

[0045] It needs to be explained that the front side 10 of blade 100 is the leading edge of the blade, that is, the side where the airflow enters, and the rear side 20 of blade 100 is the trailing edge of the blade, that is, the side where the airflow exits. Here, the airflow passes through the leading edge, is guided by the blade, flows to the trailing edge, and enters the corresponding volute flow channel from the trailing edge. t2 > t1, indicating that the second serrations 221 on the fourth segment 22 are more densely packed than the third serrations 231 on the fifth segment 23. Therefore, the area formed by the n second serrations 221 on the fourth segment 22 is also called the dense tooth area, and the area formed by multiple consecutive third serrations 231 on the fifth segment 23 is also called the comb tooth area. Secondly, L3 < L2, indicating that in the height direction of blade 100, the height of the third segment 21 is less than the height of the second segment 12. Since the fourth segment 22 and the third segment 21 are connected sequentially, the connection point between the fourth segment 22 and the third segment 21 is perpendicular to the height direction of blade 100 (e.g., ...). Figure 5The projection in the Z direction (as shown in Figure 5 ) is on the second segment 12. Additionally, L2 - L3 < L4 and L5 < L1 - L2, where L1 - L2 is the height of the first segment 11. The conditions L2 - L3 < L4 and L5 < L1 - L2 indicate that the extension of the fourth segment 22 in the height direction of the blade 100 exceeds the connection point between the first segment 11 and the second segment 12. That is, the connection between the fourth segment 22 and the fifth segment 23 in the projection perpendicular to the height direction of the blade 100 (such as the Z direction shown in Figure 5 ) is on the first segment 11. In other words, the fourth segment 22 extends from the second segment 12 to the first segment 11. Figure 5 The projection in the Z direction (as shown in Figure 5 ) is on the first segment 11. In other words, the fourth segment 22 extends from the second segment 12 to the first segment 11.

[0046] It can be understood that at the second end 40 of the blade 100, after setting the first serrations 121 on the second segment 12 at the front side 10 position, if serrations are synchronously set at the second end 40 of the rear side 20 in the corresponding area, the work capacity of the blade 100 at the second end 40 will be significantly reduced. Affected by the outflow of other areas of the blade and the internal resistance of the fan operation, the degree of turbulence in the area near the outlet of the second end 40 will increase, leading to an increase in noise. Therefore, a serration - free segment is set at the rear side 20 position of the second end 40 to ensure the overall work capacity and resistance - resistance ability of the blade 100 at the second end 40 position and avoid increasing the degree of turbulence in its nearby area.

[0047] Meanwhile, since the air intake volume of blade 100 varies along its height, the airflow changes from less to more to less from the second end 40 to the first end 30. Here, along the height of blade 100, towards the center point of blade 100, the airflow changes from less to more from the second end 40 to the center point; from the center point to the first end 30, the airflow changes from more to less. Therefore, the closer to the second end 40 and the closer to the first end 30, the less the airflow; the closer to the center point, the more the airflow. Furthermore, after the airflow passes through the first serration 121 on the front side 10, its vortex size is relatively smaller than the vortex size on the front side 10, and the number of vortices increases with the increase of the corresponding air intake volume. At the rear side 20, the fourth segment 22 mainly receives the airflow after passing through the first serration 121. Therefore, in this application, the relationships between L1, L2, L3, L4, and L5 are coupled and accurately correlated as a whole, so that the fourth segment 22 is positioned relative to the middle of the blade 100 and close to the first serration 121. In this way, the fourth segment 22 can basically receive the airflow from the first serration 121, and then guide the large and small vortices in the airflow in a targeted manner through the dense tooth area, so as to disperse the outflow of the blade 100 and increase and change the success probability of vortex shedding position. In this way, the distance between the vortex centers is increased, the disturbance of the wake flow by the shedding vortex is suppressed, thereby reducing the aerodynamic noise caused by unsteady pressure pulsation on the surface of the blade 100 and wake vortex, and thus reducing the noise when the impeller is working.

[0048] In one embodiment, such as Figure 5 and Figure 6As shown, along the height direction of the blade 100, the blade 100 is straight, and the fourth segment 22 is configured as a projection segment 222 on the front side 10, extending from the second segment 12 to the first segment 11. Here, the projection of the fourth segment 22 on the front side 10 can be interpreted as follows: the projection segment 222 is parallel to the front side 10, in which case the projection segment 222 can be translated onto the front side 10; or, the projection segment 222 is directly on the front side 10. It is understandable that the projection segment 222 extends from the second segment 12 to the first segment 11, which means that the extension of the fourth segment 22 in the height direction of the blade 100 exceeds the connection point between the first segment 11 and the second segment 12. When the airflow flows from the front side 10 to the rear side 20, the airflow at the front side 10 of the second end 40 is dispersed by the first serration 121 to form small vortices. At the rear side 20, the small vortices are mainly concentrated at the position of the fourth segment 22. Thus, the second serration 221 on the fourth segment 22 is used to further disperse and guide the small vortices, thereby more accurately dispersing the blade outflow and increasing and changing the success rate of vortex shedding. In this way, the distance between the vortex centers is further increased, the disturbance of the wake flow by the shedding vortex is suppressed, and the aerodynamic noise caused by the unsteady pressure pulsation and wake vortex on the surface of the blade 100 is reduced.

[0049] In an implementation, such as Figures 3 to 6 As shown, L1 and L2 satisfy the relationship: 0 < L2 < L1 / 3. Along the direction perpendicular to the blade height 100 (Z direction), the height of the first serration 121 is H. C 0 <H C ≤0.25*L arc It is understandable that the primary purpose of setting the first serration 121 is to disrupt vortices in the airflow and to streamline and stabilize the airflow. The work done by the blade 100 on the airflow depends mainly on the area of ​​the blade 100; therefore, while ensuring the disruption of vortices, the effective area of ​​the blade 100 must also be considered, ensuring that L1 and L2 satisfy the relationship: 0 < L2 < L1 / 3. Furthermore, the height of the first serration 121 is H. C It is also a key factor related to the effective area of ​​the blade (H). C The larger the blade, the more of the front side 10 of the blade 100 needs to be removed when machining the first saw tooth 121, and H C The smaller the value, the less the amount of leaf blade removed (100%), the better. C The smaller the value, the smoother the first serration (121) will be. C When the value is 0, it cannot disrupt the eddies in the airflow, thus making 0... <H C ≤0.25*L arc .

[0050] As a preferred option, H C The value can be 0.1*Larc 0.15*L arc 0.2*L arc 0.25*L arc And so on. Of course, H C The specific value can be set according to the actual situation.

[0051] In one embodiment, the first sawtooth 121 can be configured as an arc-shaped tooth, a trapezoidal tooth, a triangular tooth, a sine tooth, etc. In this embodiment, the first sawtooth 121 is configured as an arc-shaped tooth, the radius of which is R, 0 <R≤0.125*L arc .

[0052] Here, the value of R can be 0.05 * L. arc 0.10*L arc 0.15*L arc 0.12*L arc 0.125*L arc Of course, the specific value of R can be set according to the actual situation.

[0053] like Figure 1 and Figure 6 As shown, in one embodiment, along the direction perpendicular to the height of the blade 100 (i.e., the Z direction), the second serration 221 and the third serration 231 have the same height, both being h.

[0054] It is understood that a flow channel 101 for airflow is formed between two adjacent blades 100, and the work done by the blades 100 on the airflow depends on the shorter flow channel 101. If the lengths of two adjacent blades are inconsistent in their arc length direction, it will cause the length of the flow channel 101 to be inconsistent in the height direction of the blades 100, that is, in the blade height direction (Y direction), which will cause internal flow loss. However, this application makes the heights of the second serration 221 and the third serration 231 the same, so that the flow channel length is consistent in their height direction, thereby avoiding additional internal flow loss caused by the difference.

[0055] like Figure 6 As shown, in one embodiment, along the height direction of the blade 100, from the second segment 12 to the first end 30, the tooth width of the n second serrations 221 is t. 11 t 12 ... t 1n-1 t 1n (4≤n), and the tooth width satisfies t 1n ≤t 1n-1 ≤...≤t 12 ≤t 11 , 3h≤t1≤10h.

[0056] It is understandable that the tooth width of the n second saw teeth 221 is t.11 t 12 ... t 1n-1 t 1n (4≤n), and the tooth width satisfies t 1n ≤t 1n-1 ≤...≤t 12 ≤t 11 That is, the arrangement of the second serrations 221 becomes increasingly dense from the second segment 12 to the first end 30. The fourth segment 22 is relatively close to the second end 40, and the airflow at this position carries the most vortices. Most of the airflow in the fourth segment 22 passes through the first serrations 121 in the second segment 12 (which disperses the airflow, making it more turbulent). At the same time, since the air intake of the blade 100 varies in its height direction, the airflow increases from the second end 40 to the first end 30. That is, from the second end 40 to the first end 30, the closer to the second end 40, the smaller the airflow, and the closer to the first end 30, the larger the airflow. A larger airflow indicates a greater number of vortices carried in the airflow. Therefore, this application combines the airflow characteristics at the fourth segment 22 position and sets the second serrations 221 to become increasingly dense, thereby better dealing with the relatively dense vortices in the airflow.

[0057] Meanwhile, t1 satisfies 3h ≤ t1 ≤ 10h, where t1 is the tooth width of the second sawtooth 221, and h represents the height of the sawtooth in the Z direction. The ratio between t1 and h relates to the slope of the second sawtooth 221. In a right triangle, t1 and h represent the two legs of the right angle. The larger t1 is, the smaller the value of sin(t1 / h), meaning the angle corresponding to the right angle h is smaller, indicating that the second sawtooth 221 is generally more gentle. Similarly, the smaller t1 is, the larger the value of sin(t1 / h), meaning the angle corresponding to the right angle h is larger, indicating that the second sawtooth 221 is generally steeper. Here, the slope value relates to the location where the vortex detaches. The larger the slope, the greater the probability that the vortex in the airflow will detach at different locations, and vice versa. However, if the slope is too large, the vortex in the airflow will also collide with the next sawtooth, thus aggravating the collision between vortices and making the airflow more turbulent. Therefore, in order to balance the above situation, the relationship between t1 and h should be satisfied: 3h≤t1≤10h.

[0058] Preferably, the value of t1 can be 3h or 4h. c 5h, 6h, 7h, 8h, 9h, and 10h, etc. Of course, the specific value of t1 can be set according to the actual situation.

[0059] In one embodiment, t2 and h satisfy the relationship: 4h ≤ t2 ≤ 15h. It can be understood that t2 is the tooth width of the third sawtooth 231, and h represents the height of the sawtooth in the Z direction. The ratio of t2 to h relates to the slope of the third sawtooth 231. In a right triangle, t2 and h represent the two legs of the right angle. The larger t2 is, the smaller the sin(t2 / h) value, meaning the smaller the angle corresponding to the right angle h, indicating that the third sawtooth 231 is generally more gentle. Similarly, the smaller t2 is, the larger the sin(t2 / h) value, meaning the larger the angle corresponding to the right angle h, indicating that the third sawtooth 231 is generally steeper. Here, the slope value relates to the vortex shedding position; a larger slope increases the probability of the vortex detaching from different positions in the airflow, and vice versa. However, if the slope is too steep, the airflow exiting along the rear 20° will easily collide with the airflow exiting from the next serration, thus exacerbating the collision between airflows and making the airflow more turbulent. Therefore, to balance the above situation, the relationship between t2 and h is satisfied: 4h ≤ t2 ≤ 15h.

[0060] Preferably, t2 can be 4h. c 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, and 15h, etc. Of course, the specific value of t1 can be set according to the actual situation.

[0061] In one embodiment, 0.5mm ≤ h ≤ 2.5mm. It can be understood that h represents the serration height. The larger the serration dimension perpendicular to the blade height, the greater the amount of material removed from the rear side 20 of the blade 100; conversely, the smaller the serration dimension perpendicular to the blade height, the smaller the amount of material removed from the rear side 20 of the blade 100. The overall area of ​​the blade 100 is one of the key factors in the work done by the blade 100 on the airflow (allowing the gas to gain energy (static pressure and kinetic energy)). If too much material is removed from the blade 100, its ability to do work on the airflow will be weakened. Simultaneously, the serrations are there to disperse vortices; if the height of the serrations in the Z direction is too small, their effect on vortices in the airflow will be even smaller. Therefore, h is set here to: 0.5mm ≤ h ≤ 2.5mm. This not only satisfies the work requirement of the blade 100 on the airflow (i.e., ensuring sufficient flow channel length) but also satisfies the function of the serrations in dispersing vortices in the airflow.

[0062] Preferably, the value of h can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, etc. Of course, the specific value of h can be set according to the actual situation.

[0063] In one embodiment, the relationship between L2 and L3 satisfies: L2 / 2 ≤ L3 < L2. It can be understood that the third section 21 is mainly provided to correspond and match with the second section 12 to ensure the work capacity of the blade 100 at the second end 40.

[0064] In one embodiment, as Figure 5 shown, along the height direction of the blade 100, the rear side 20 further includes a sixth section 24. The sixth section 24 is connected to one end of the fifth section 23 away from the fourth section 22, and the sixth section 24 extends to the end of the first end 30 and is configured as a non-serrated section. It can be understood that at the position of the first end 30 of the blade 100, the air flow rate is less. In order to ensure the work capacity of the blade 100 at the first end 30, the sixth section 24 is set as a non-serrated section to ensure the area of the blade 100 at the position of the sixth section 24.

[0065] Preferably, as Figure 6 shown, the height of the sixth section 24 is L6, satisfying 0 < L6 ≤ t2, then L5 = L1 - L3 - L4 - L6.

[0066] 0 < L6 ≤ t2, that is, the maximum height of L6 is at most the tooth width t2 of the third serration 231. In this way, more and complete third serrations 231 can be provided in the fifth section 23, and more third serrations 231 are provided to change the vortex detachment position.

[0067] In this application, to further verify the comparison between this application and the original blade, the motor input current of the fan corresponding to the impeller of the blade of the present invention is reduced by 0.02 A when reaching the same laboratory working condition flow rate. Under the same experimental working condition flow rate, the following experimental data table (as shown in Table 1) is obtained:

[0068] Table 1

[0069]

[0070]

[0071] In Table 1, the control group 1 is set as the original blade, that is, no serrations are provided at the leading edge and trailing edge of the blade. The control group 2 is based on the control group 1, and only serrations are provided at the leading edge of the blade; the control group 3 is based on the control group 1, and only serrations are provided at the trailing edge of the blade; the control group 4 is based on the control group 1, and serrations are provided at both the leading edge and trailing edge of the blade . Here, the measurement units of L2, L3, L4, L5, L6, and h are all millimeters (mm). "-" indicates a decrease. For example, -0.3 dB means that the noise is reduced by 0.3 dB compared to the original blade.

[0072] Understandably, as shown in control group 4, placing serrations on both the leading and trailing edges of the blade did not produce as good a noise reduction effect as placing serrations only on the leading edge (control group 2) or only on the trailing edge (control group 3). This application addresses this technical problem by combining the serrations on the leading and trailing edges of the blade through a coupling mechanism. This further disperses and guides small vortices, thereby more accurately dispersing the blade outflow and increasing the success rate of changing the vortex shedding position. This further increases the distance between vortex centers, suppresses the disturbance of the wake flow by the shedding vortex, and reduces the aerodynamic noise caused by unsteady pressure pulsations and wake vortices on the blade surface.

[0073] like Figure 1 As shown, in one embodiment, this application also provides a centrifugal fan impeller 200, which includes blades 100. The specific structure and principle of the blades 100 have been described in detail above and will not be repeated here.

[0074] In one embodiment, this application also provides a centrifugal fan, which includes the aforementioned blades 100 or the aforementioned centrifugal fan impeller 200.

[0075] In one embodiment, this application also provides a range hood, which includes the aforementioned blades 100 or the aforementioned centrifugal fan.

[0076] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.

Claims

1. A blade for a centrifugal fan impeller, wherein the blade is arc-shaped and the arc length of the blade is denoted as L. arc Along the arcuate extension direction of the blade, the blade has a front side and a rear side arranged opposite to each other, and the airflow is guided from the front side to the rear side; characterized in that, Let the height of the blade be L1. Along the height direction of the blade, the blade has a first end and a second end that are arranged opposite to each other. Along the height direction of the blade, the front side is configured as a first segment and a second segment. The first segment is located near the first end, and the second segment is located near the second end. The height of the second segment is denoted as L2, and multiple continuous first serrations are provided on the entire second segment. Along the height direction of the blade and from the second end to the first end, the rear side is configured with at least a third segment, a fourth segment, and a fifth segment connected in sequence; the third segment is configured as a non-serrated segment with a height of L3; the fourth segment has a height of L4 and extends from the second segment to the first segment in the direction from the second end to the first end; the fifth segment has a height of L5. The fourth segment has n consecutive second sawtooth teeth with a tooth width of t1. The fifth segment has multiple consecutive third sawtooth teeth with a tooth width of t2, where t2 > t1. L1, L2, L3, L4, and L5 satisfy the following relationship: L3 < L2, L5 < L1-L2.

2. The blade for a centrifugal fan impeller according to claim 1, characterized in that, Along the direction perpendicular to the blade height, the second and third saw teeth have the same height, both set to h.

3. The blade for a centrifugal fan impeller according to claim 2, characterized in that, Along the height direction of the blade, from the second end to the first end, the tooth width of the n second serrations is set to t. 11 t 12 ... t 1n-1 t 1n (4≤n), and the widths of each tooth satisfy: t 1n ≤t 1n-1 ≤...≤t 12 ≤t 11 , 3h≤t1≤10h.

4. The blade for a centrifugal fan impeller according to claim 2, characterized in that, The relationship between t2 and h is: 4h≤t2≤15h.

5. The blade for a centrifugal fan impeller according to claim 2, characterized in that, h satisfies the following relationship: 0.5mm≤h≤2.5mm.

6. The blade for a centrifugal fan impeller according to claim 2, characterized in that, The relationship between L2 and L3 is: L2 / 2 ≤ L3 < L2.

7. The blade for a centrifugal fan impeller according to claim 1, characterized in that, Along the height direction of the blade, the rear side also includes a sixth segment, which is connected to the end of the fifth segment away from the fourth segment. The sixth segment is configured as a non-serrated end and extends to the end position of the first end and is configured as a straight segment.

8. The blade for a centrifugal fan impeller according to claim 7, characterized in that, The height of the sixth segment is L6, and the height of the fifth segment is L5. L5 and L6 satisfy the following relationship: 0 <L6≤t2,L5=L1-L3-L4-L6。 9. The blade for a centrifugal fan impeller according to claim 1, characterized in that, The relationship between L1 and L2 is: 0 < L2 < L1 / 3; Along the direction perpendicular to the blade height, the height of the first serration is H. C 0 <H C ≤0.25*L arc .

10. The blade for a centrifugal fan impeller according to claim 9, characterized in that, The first sawtooth is configured as an arc tooth, and the radius of the arc tooth is R, 0. <R≤0.125*L arc .

11. A centrifugal fan impeller, characterized in that, Includes the blade as described in any one of claims 1-10.

12. A centrifugal fan, characterized in that, Includes the blade as described in any one of claims 1-10.

13. A range hood, characterized in that, Includes the blade as described in any one of claims 1-10.

Images