Centrifugal fan

Abstract

The utility model provides a centrifugal fan, the centrifugal fan includes volute and sets up in the volute a plurality of blades, the blade still includes: the bending section, the bending section extends from the import end of blade to the export end of blade, along the height direction of blade, the export end of blade forms the first part of being located above the bending section and the second part of being located below the bending section through the bending section, the first part and the second part staggered setting, wherein, the height of first part and the export end height ratio of blade 0.5 0.8. Through setting bending section, to make blade's first part and second part have the phase difference along the height direction of blade, break the shedding vortex of blade export end, reduce the wide frequency noise of fan. And make the airflow downward can reduce the collision with the wall, can effectively promote the aerodynamic performance and efficiency of fan and reduce the aerodynamic noise.

Description

Technical Field

[0001] This utility model specifically relates to a centrifugal fan. Background Technology

[0002] To ensure sufficient outlet area, conventional fans often employ a design where the fan is positioned slightly upwards and the center of the air duct is lowered. This results in turbulent airflow after radial exit and collision with the wall, impacting fan efficiency and generating aerodynamic noise. Aerodynamic noise includes discrete noise generated by the blades cutting through the airflow and vortex noise from the detached airflow at the blade trailing edge. The former produces noise peaks, creating a harsh sound that is extremely uncomfortable for the human ear; while the latter, generated by the downward velocity component after the airflow from the blade trailing edge collides with the inner wall of the volute, easily produces vortex noise, leading to a poor user experience. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the shortcomings of the existing technology, such as large rotational noise and eddy current noise, and poor user experience, and to provide a centrifugal fan.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] A centrifugal fan includes a volute and a plurality of blades disposed within the volute, the blades further comprising:

[0006] The bending section extends from the inlet end of the blade to the outlet end of the blade. Along the height direction of the blade, the outlet end of the blade forms a first part above the bending section and a second part below the bending section. The first part and the second part are staggered. The height of the first part is 0.5-0.8 times the height of the outlet end of the blade.

[0007] In this design, a bending section is incorporated to create a phase difference between the first and second parts of the blade along the blade's height direction, effectively offsetting them. This allows the detachment vortices generated at different positions on the blade's outlet end by the phase-differentiated first and second parts to interfere with each other, disrupting the detachment vortices generated at the blade's outlet end and reducing the fan's broadband noise. Because the blade is positioned slightly upwards, the ratio of the height of the first part of the bending section to the height of the blade's outlet end is limited. This results in a reduced downward velocity component (Vy) and a decreased radial component (Vx) in the airflow exiting the blade's outlet. The downward airflow reduces collisions with the wall, thereby minimizing collision losses and collision-induced vortices. This effectively improves the fan's aerodynamic performance and efficiency while reducing aerodynamic noise.

[0008] Preferably, the blade has at least one of the bending sections, and when the number of bending sections is greater than or equal to two, the height ratio of the first portion near the inlet of the volute to the outlet end of the blade along the height direction of the blade is 0.5-0.8.

[0009] In this scheme, the above settings are used to further enhance the blades' interference with shedding vortices, thereby reducing the broadband noise of the wind turbine.

[0010] Preferably, along the projection direction of the blade, the phase angle between the first part and the second part is θ, where θ = 0 to 360 / 2n, and n is the number of blades.

[0011] In this solution, the above settings are used to reduce the impact of rotational noise, i.e., BPF noise.

[0012] Preferably, along the height direction of the blade, the ratio of the height of the third portion of the blade's inlet end located above the bent section to the height of the blade's inlet end is 0.3-0.5.

[0013] In this scheme, the above settings are used to reduce the rotational noise generated by the blade inlet cutting the airflow.

[0014] Preferably, the cross-section of the bent section is a straight line, and when the cross-section of the bent section is a straight line, the cross-section of the bent section forms an angle of 0-45° with the bottom plate of the volute.

[0015] In this scheme, the above settings are used to make the airflow flowing to the bend section generate a component that flows downward toward the fan outlet. That is, the flow loss of the airflow in the axial component is smaller, and the radial outflow direction of the airflow changes from horizontal to downward tilting at a certain angle, thereby improving the aerodynamic performance and efficiency of the fan.

[0016] Preferably, the cross-section of the bending segment is a curve. When the cross-section of the bending segment is a curve, the bending segment is formed by connecting multiple curve segments sequentially from the inlet end of the blade to the outlet end of the blade.

[0017] In this scheme, the above settings are used to make the airflow flowing to the bend section generate a component that flows downward toward the fan outlet. That is, the flow loss of the airflow in the axial component is smaller, and the radial outflow direction of the airflow changes from horizontal to downward tilting at a certain angle, thereby improving the aerodynamic performance and efficiency of the fan.

[0018] Preferably, there is a transition section between the inlet of the volute and the inlet of the blade, the cross section of the transition section is an arc, and the radius of the arc is 0.15-0.25 times the inlet diameter of the blade.

[0019] In this solution, the above settings are used to ensure the air intake volume of the fan.

[0020] Preferably, the ratio of the inlet diameter of the blade to the outlet diameter of the volute is 0.25-0.8.

[0021] In this solution, the above settings are used to ensure the aerodynamic performance of the fan.

[0022] Preferably, along the height direction of the blade, the ratio of the blade's inlet height to its inlet diameter is 0.25-0.4.

[0023] In this solution, the above settings are used to ensure the air intake volume of the blades.

[0024] Preferably, along the height direction of the blade, the ratio of the blade's outlet height to its inlet diameter is 0.25-0.4.

[0025] In this scheme, the above settings ensure that the blades have sufficient outlet height to form a flow split and meet the aerodynamic performance requirements of the fan.

[0026] The positive and progressive effects of this invention are as follows: By incorporating a bending section, the first and second parts of the blade are staggered along the blade's height direction. This allows the detachment vortices generated at different positions on the blade's outlet end to interfere with each other, disrupting the detachment vortices and reducing broadband noise of the fan. Because the blade is positioned slightly upwards, the ratio of the height of the first part of the bending section to the height of the blade's outlet end is limited. This reduces the downward velocity component Vy and the radial component Vx of the airflow exiting the blade outlet. The downward airflow reduces collisions with the wall, thereby reducing collision losses and collision separation vortices, effectively improving the fan's aerodynamic performance and efficiency while reducing aerodynamic noise. Attached Figure Description

[0027] Figure 1 This is a perspective view of the centrifugal fan of Embodiment 1 of this utility model.

[0028] Figure 2 This is a top view of the centrifugal fan of Embodiment 1 of this utility model.

[0029] Figure 3 This is a schematic diagram of the structure of the bent section of Embodiment 1 of this utility model, where the cross-section is a straight line.

[0030] Figure 4 This is a perspective view of a centrifugal fan with a curved cross-section in Embodiment 2 of this utility model.

[0031] Figure 5 This is a schematic diagram of the structure of the bent section of Embodiment 2 of this utility model, which has a curved cross-section.

[0032] Explanation of reference numerals in the attached figures:

[0033] Snail shell 1

[0034] Leaf 2

[0035] Bending section 21

[0036] Import end 22

[0037] Export end 23

[0038] Part 1, Chapter 24

[0039] Part 2, 25

[0040] Part 3, 26

[0041] Transition section 3

[0042] Height direction A Detailed Implementation

[0043] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0044] Example 1

[0045] This embodiment provides a centrifugal fan, the specific structure of which is as follows: Figure 1 , Figure 2 and Figure 3 As shown, the centrifugal fan includes a volute 1 and several blades 2 disposed within the volute 1. The blades 2 also include:

[0046] The bending section 21 extends from the inlet end 22 of the blade 2 to the outlet end 23 of the blade 2. Along the height direction A of the blade 2, the outlet end 23 of the blade 2 forms a first part 24 above the bending section 21 and a second part 25 below the bending section 21. The first part 24 and the second part 25 are staggered. The height ratio of the first part 24 to the height of the outlet end 23 of the blade 2 is 0.5-0.8.

[0047] Specifically, several blades 2 are spaced apart by bushings arranged around the axis of the volute 1. The inlet end 22 of the blade 2 is located near the inlet of the volute 1, and the outlet end 23 of the blade 2 is located near the outlet of the volute 1. The inlet end 22 is the leading edge of the blade 2, and the outlet end 23 is the trailing edge of the blade 2. A bent section 21 on the blade 2 extends from the inlet end 22 toward the outlet end 23, dividing the blade 2 into a first part 24 and a second part 25 along the height direction A of the blade 2. The first part 24 is located above the bent section 21, i.e., near the inlet of the volute 1 along the height direction A of the blade 2, while the second part 25 is located below the bent section 21, i.e., away from the inlet of the volute 1 along the height direction A of the blade 2. The height of the first part 24 is b21, and the height of the outlet end 23 of the blade 2 is b2. The ratio of b21 / b2 is 0.5-0.8.

[0048] Meanwhile, the first part 24 and the second part 25 have a phase difference along the height direction A of the blade 2, that is, they are staggered, so as to utilize the mutual interference of the shedding vortices of the first part 24 and the second part 25 at different positions of the outlet end 23 of the blade 2, which have a phase difference, to disrupt the shedding vortices generated at the outlet end 23 and reduce the broadband noise of the fan.

[0049] Furthermore, since blade 2 is positioned slightly upwards within the volute 1, the height ratio of the first portion 24 of the bent section 21 to the outlet end 23 of blade 2 is restricted. This results in the airflow exiting blade 2 having a downward velocity component Vy, while the radial component Vx of the airflow decreases. It is understood that the increased downward airflow reduces the collision between the radially flowing airflow and the wall of the volute 1, thereby reducing collision losses and collision separation vortices. This effectively improves the aerodynamic performance and efficiency of the fan and reduces aerodynamic noise.

[0050] Compared to traditional axial centrifugal fans, which involve two 90-degree turns of the airflow after axial intake and radial exit via guide vanes, resulting in significant airflow losses, this embodiment utilizes the phase difference between the first part 24 and the second part 25. Furthermore, the bent section 21 on the blade 2 extends from the inlet end 22 towards the outlet end 23, creating an inclined surface on the blade 2. This allows the airflow to have a downward component after passing through the blade 2, resulting in less airflow loss in the axial component and consequently improving fan efficiency.

[0051] It should be noted that, in this embodiment, with the rotation direction as a reference, the positions of the first part 24 and the second part 25 along the rotation direction are such that the second part 25 comes first and the first part 24 comes last. Conversely, the same applies if the first part 24 comes first and the second part 25 comes last.

[0052] Furthermore, in this embodiment, the blade 2 has at least one bent section 21. When the number of bent sections 21 is greater than or equal to two, the height ratio of the first part 24 near the inlet of the volute 1 to the outlet end 23 of the blade 2 along the height direction of the blade 2 is 0.5-0.8.

[0053] Specifically, when there is one bending section 21, the height ratio of the first portion 24 formed by the bending section 21 to the height of the outlet end 23 is 0.5-0.8. When there are two or more bending sections 21, along the height direction of the blade 2, the height ratio of the first portion 24 near the inlet of the volute 1 to the height of the outlet end 23 is also 0.5-0.8. This height ratio of the first portion 24 to the outlet end 23 is used to interfere with detachment vortices, thereby reducing the broadband noise of the fan.

[0054] In this embodiment, along the projection direction of the blade 2, the phase angle between the first part 24 and the second part 25 is θ, where θ = 0 to 360 / 2n, and n is the number of blades 2. By limiting the range of the phase angle θ, the first part 24 and the second part 25 can have different blade shapes, and the inlet and outlet angles can be the same or different. Based on the staggered arrangement along the projection direction of the blade 2, the BPF noise formed by the leading edge of the blade 2 cutting the airflow can be reduced, thereby effectively reducing rotational noise.

[0055] In this embodiment, along the height direction A of the blade 2, the height ratio of the third part 26 above the bending section 21 of the inlet end 22 of the blade 2 to the height of the inlet end 22 of the blade 2 is 0.3-0.5.

[0056] Specifically, the height of the third part 26 above the bending section 21 at the inlet end 22 of blade 2 is b11, while the height of the inlet end 22 is b1, with the ratio of b11 / b1 being 0.3-0.5. This is to reduce the rotational noise generated by the inlet end 22 of blade 2 cutting the airflow by limiting the height ratio.

[0057] In this embodiment, the cross-section of the bending section 21 is a straight line. When the cross-section of the bending section 21 is a straight line, the cross-section of the bending section 21 forms an angle of 0-45° with the bottom plate of the volute 1.

[0058] Specifically, the cross-section of the bending section 21 can be a straight line parallel to the bottom plate of the volute 1. From the shape of the blade 2, the bending section 21 is a plane parallel to the bottom plate of the volute 1, that is, the cross-section of the bending section 21 forms a 0° angle with the bottom plate of the volute 1. By using a plane parallel to the bottom plate of the volute 1, the airflow flowing to the bending section 21 generates a component that flows downward toward the fan outlet. That is, the flow loss of the airflow in the axial component is smaller, and the radial outflow direction of the airflow changes from horizontal to downward inclined at a certain angle, thereby improving the aerodynamic performance and efficiency of the fan.

[0059] In addition, in other embodiments, the bending section 21 may be a plane inclined to the bottom plate of the volute 1. The inclination direction of the bending section 21 may be inclined about the radial direction of the volute 1 or about the rotation direction of the blade 2. The inclination angle between the bending section 21 and the bottom plate of the volute 1 is less than or equal to 45°. By setting the bending section 21 at an inclination, the airflow component flowing downward toward the fan outlet is increased, thereby further improving the aerodynamic performance and efficiency of the fan.

[0060] In this embodiment, there is a transition section 3 between the inlet of the volute 1 and the inlet of the blade 2. The cross-section of the transition section 3 is an arc, and the radius of the arc is 0.15-0.25 times the inlet diameter of the blade 2.

[0061] Specifically, the radius of the arc is r, the inlet diameter of blade 2 is D1, and the ratio of r / D1 is 0.15-0.25. This is to limit the radius of transition section 3 and the inlet diameter to ensure the air intake of the fan and avoid the situation where the air intake is too small to meet the fan's needs.

[0062] In this embodiment, the ratio of the inlet diameter of blade 2 to the outlet diameter of volute 1 is 0.25-0.8.

[0063] Specifically, the inlet diameter of blade 2 is D1, the outlet diameter of volute 1 is D2, and the ratio of D1 / D2 is 0.25-0.8. By limiting the ratio of the inlet of blade 2 to the outlet of volute 1, the aerodynamic performance of the fan is guaranteed.

[0064] In this embodiment, along the height direction A of the blade 2, the ratio of the inlet height of the blade 2 to the inlet diameter of the blade 2 is 0.25-0.4.

[0065] Specifically, the inlet height of blade 2 is the height of inlet end 22, that is, the inlet height of blade 2 is b1, and the inlet diameter of blade 2 is D1. By limiting the ratio of the inlet height of blade 2 to the inlet diameter of blade 2, sufficient airflow can enter the inlet end 22 of blade 2, thus ensuring the air intake volume of blade 2.

[0066] In this embodiment, along the height direction A of the blade 2, the ratio of the outlet height of the blade 2 to the inlet diameter of the blade 2 is 0.25-0.4.

[0067] Specifically, the outlet height of blade 2 is the height of the outlet end 23 of blade 2. That is, the outlet height of blade 2 is b2, and the inlet diameter of blade 2 is D1. By limiting the ratio of the outlet height of blade 2 to the inlet diameter of blade 2, it is ensured that the outlet end 23 of blade 2 has sufficient outlet height to form a flow split and meet the aerodynamic performance of the fan.

[0068] Example 2

[0069] like Figure 4 and Figure 5 As shown, the structure of blade 2 in this embodiment is roughly the same as that of blade 2 in embodiment 1. The difference is that in this embodiment, the cross section of the bending section 21 is a curve. When the cross section of the bending section 21 is a curve, the bending section 21 is formed by connecting multiple curves sequentially from the inlet end 22 of blade 2 to the outlet end 23 of blade 2.

[0070] Specifically, the cross-section of the bending section 21 can be composed of multiple curved segments connected sequentially. From the shape of the blade 2, the bending section 21 is not a blade that bends in a single direction. Compared to a straight cross-section, when the cross-section of the bending section 21 is curved, the inlet end 22 and outlet end 23 of the blade 2 can form more and different inlet angles and blade shapes. This allows the airflow flowing into the bending section 21 to form more shedding vortices. These different shedding vortices interfere with each other, further improving the noise reduction effect on the fan's wideband noise.

[0071] Furthermore, in this embodiment, the continuous curve of the cross-section of the bending section 21 can increase the downward flow component towards the fan outlet. That is, compared to the straight section of the bending section 21, when the cross-section of the bending section 21 is curved, the flow loss of the airflow in the axial component is smaller, increasing the downward component of the airflow, so that the airflow direction makes an angle of about 45° with the air duct inside the volute 1, thereby further improving the fan efficiency.

[0072] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A centrifugal fan, the centrifugal fan comprising a volute and a plurality of blades disposed within the volute, characterized in that, The blade also includes: The bending section extends from the inlet end of the blade to the outlet end of the blade. Along the height direction of the blade, the outlet end of the blade forms a first part above the bending section and a second part below the bending section. The first part and the second part are staggered. The height of the first part is 0.5-0.8 times the height of the outlet end of the blade.

2. The centrifugal fan as described in claim 1, characterized in that, The blade has at least one of the bending sections. When the number of bending sections is greater than or equal to two, the height ratio of the first part near the inlet of the volute to the outlet end of the blade along the height direction of the blade is 0.5-0.

8.

3. The centrifugal fan as described in claim 1, characterized in that, Along the projection direction of the blade, the phase angle between the first part and the second part is θ, where θ = 0 to 360 / 2n, and n is the number of blades.

4. The centrifugal fan as described in claim 3, characterized in that, Along the height direction of the blade, the ratio of the height of the third portion of the blade's inlet end located above the bent section to the height of the blade's inlet end is 0.3-0.

5.

5. The centrifugal fan as described in claim 4, characterized in that, The cross-section of the bending section is a straight line. When the cross-section of the bending section is a straight line, the cross-section of the bending section forms an angle of 0-45° with the bottom plate of the volute.

6. The centrifugal fan as described in claim 4, characterized in that, The cross-section of the bending section is a curve. When the cross-section of the bending section is a curve, the bending section is formed by connecting multiple curve segments sequentially from the inlet end of the blade to the outlet end of the blade.

7. The centrifugal fan as described in claim 1, characterized in that, There is a transition section between the inlet of the volute and the inlet of the blade. The cross-section of the transition section is an arc, and the radius of the arc is 0.15-0.25 times the inlet diameter of the blade.

8. The centrifugal fan as described in claim 1, characterized in that, The ratio of the inlet diameter of the blade to the outlet diameter of the volute is 0.25-0.

8.

9. The centrifugal fan as described in claim 1, characterized in that, Along the height direction of the blade, the ratio of the blade's inlet height to its inlet diameter is 0.25-0.

4.

10. The centrifugal fan as described in claim 1, characterized in that, Along the height direction of the blade, the ratio of the blade's outlet height to its inlet diameter is 0.25-0.4.

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