High-performance centrifugal fan

Abstract

The invention discloses a high-performance centrifugal fan, and belongs to the technical field of centrifugal fan structure improvement, an air inlet groove is formed in a base, is located between fan blades and a main air outlet, is of an arc-shaped structure and comprises an inner arc line and an outer arc line, and the inner arc line and the outer arc line both take the center of the fan blades as the circle center; the distance between the inner arc line and the center of the fan blade is smaller than the distance between the outer arc line and the center of the fan blade, the end of the inner arc line and the end of the outer arc line are connected through a first straight line and a second straight line which are equal in length, and the first straight line and the second straight line are arranged in parallel and are both perpendicular to the plane where the main air outlet is located. The first straight line and the second straight line are located between the tongue opening position and the airflow vertical blowing-out position. The aerodynamic efficiency can be improved, and vortex noise and aerodynamic noise can be effectively reduced.

Description

Technical Field

[0001] The invention relates to a high-performance centrifugal fan, belonging to the technical field of centrifugal fans. Background Art

[0002] Conventional centrifugal fans experience different air inlet conditions on the cover and base sides. The base side has greater kinetic energy, while the cover side lacks it. Under the influence of the pressure gradient, the boundary layer of the airflow on the cover side separates first and then draws toward the high-speed area on the base side. This causes airflow separation at the cover outlet, generating a vortex. This not only increases power consumption and reduces aerodynamic efficiency, but also generates vortex noise. Furthermore, this unbalanced pressure results in poor pressure distribution at the tongue, significantly increasing aerodynamic noise. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a high-performance centrifugal fan that can improve aerodynamic efficiency and effectively reduce eddy current noise and aerodynamic noise.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A high-performance centrifugal fan comprises an upper cover, fan blades and a base, a main air outlet is formed between the ends of the upper cover and the base, an air inlet slot is opened on the base, the air inlet slot is located between the fan blades and the main air outlet, the air inlet slot is an arc-shaped structure, the air inlet slot comprises an inner arc line and an outer arc line, the inner arc line and the outer arc line both take the center of the fan blade as the center of the circle, the distance between the inner arc line and the center of the fan blade is smaller than the distance between the outer arc line and the center of the fan blade, the end of the inner arc line and the end of the outer arc line are connected by a first straight line and a second straight line of equal length, the first straight line and the second straight line are arranged in parallel and perpendicular to the plane where the main air outlet is located, and the first straight line and the second straight line are located between the tongue position and the position where the air flow is blown out vertically.

[0006] The inner arc line is 1-2 mm away from the tip of the fan blade.

[0007] The outer arc line is 1.5 to 3 mm away from the tip of the fan blade.

[0008] The distance between the inner arc line and the outer arc line is 0.5-1.5 mm.

[0009] The inner arc line, the outer arc line, the first straight line and the second straight line are all chamfered with R angles.

[0010] The inner arc line is 1.2-1.8 mm away from the tip of the fan blade.

[0011] The outer arc line is 2.0-2.5 mm away from the tip of the fan blade.

[0012] The centrifugal fan has a single air outlet or a double air outlet.

[0013] Beneficial effects of the present invention: The present invention provides a high-performance centrifugal fan, in which slots are opened on the base around the position where the fan is prone to generate separation vortices to form air inlet slots. Since there is a pressure difference between the internal blade tip high-speed area and the outside of the base, the airflow is affected by the internal blade tip high-speed area, so that the intake air has a certain amount of energy. The airflow flowing into the air inlet slot is deeply mixed with the airflow in the mainstream high-speed area, balancing the internal pressure gradient, delaying the separation of the upper cover boundary layer, and greatly weakening the energy and form of the separation vortex, which not only improves the aerodynamic efficiency but also reduces the vortex noise. In addition, the intake air compensates for the pressure difference at the tongue mouth to a certain extent, reduces the pressure gradient at the tongue mouth, and effectively reduces the aerodynamic noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a front view structural diagram of a centrifugal fan in the prior art;

[0015] Figure 2 It is a side view structural diagram of a centrifugal fan in the prior art;

[0016] Figure 3 is a front view structural schematic diagram of the high-performance centrifugal fan provided in this embodiment;

[0017] Figure 4 Schematic diagram of the structure of the air inlet slot provided in this embodiment;

[0018] Figure 5 is a front view structural schematic diagram of the high-performance centrifugal fan provided in this embodiment;

[0019] Figure 6 is a schematic side view of the high-performance centrifugal fan provided in this embodiment;

[0020] Figure 7 Schematic diagram of the air outlet of the high-performance centrifugal fan provided in this embodiment before and after the improvement;

[0021] Figure 8 is a schematic side view of the high-performance centrifugal fan provided in this embodiment;

[0022] Figure 9 is a front view structural schematic diagram of the high-performance centrifugal fan provided in this embodiment;

[0023] The reference numerals in the figure are as follows: 1 - air inlet slot; 11 - inner arc line; 12 - outer arc line; 13 - first straight line; 14 - second straight line. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0025] like Figure 2 As shown in Figure 2, by observing the section X=0, it can be found that the wall separation vortex intensity near the upper cover is relatively large, which greatly reduces the aerodynamic efficiency of the fan and increases the vortex noise. Figure 1 As shown in the figure, the area between the existing centrifugal fans AB is the area where the air flow separation causes serious eddy current loss. x = -10mm, B x = -17.5mm, blade center x=0, when the airflow blowing angle starts to decrease from 90°, a separation vortex begins to form, and it is more serious between AB.

[0026] like Figure 3 As shown, the present invention discloses a high-performance centrifugal fan, comprising an upper cover, fan blades and a base, wherein a main air outlet is formed between the ends of the upper cover and the base, and an air inlet slot 1 is provided on the base, and the air inlet slot 1 is located between the fan blades and the main air outlet. Figure 4 As shown, the air inlet slot 1 has an arc-shaped structure, and the air inlet slot 1 includes an inner arc line 11 and an outer arc line 12. The inner arc line 11 and the outer arc line 12 both take the center of the fan blade as the center of the circle, and the distance between the inner arc line 11 and the center of the fan blade is smaller than the distance between the outer arc line 12 and the center of the fan blade. The end of the inner arc line 11 is connected to the end of the outer arc line 12 by a first straight line 13 and a second straight line 14 of equal length. The first straight line 13 and the second straight line 14 are arranged in parallel and are both perpendicular to the plane where the main air outlet is located. The first straight line 13 and the second straight line 14 are located between the tongue position and the position where the airflow is blown out vertically.

[0027] like Figure 5 As shown, the fan blade radius of the present invention is 29mm, and an arc hole is made between AB. AB is the area where the air flow separation produces serious eddy loss. In the figure, A x = -10mm, B x = -17.5mm, the center of the fan blade x=0, point A (corresponding to the position of the second straight line 14) does not exceed the vertical blowing position of the air flow, and point B (corresponding to the position of the first straight line 13) does not exceed the tongue position.

[0028] like Figure 6 and Figure 7 As shown in the figure, by observing the section X=0, it can be found that the wall separation vortex near the upper cover is significantly weakened, the shape is reduced, and the outlet airflow is smoother. This is mainly because the airflow outside the slot on the side wall of the base enters, balancing the pressure difference caused by the high-speed airflow on the inner wall of the base, preventing the airflow on the upper cover from replenishing the high-speed area of ​​the base, thereby largely preventing the airflow separation and weakening the vortex area.

[0029] The present invention designs a slot on the base around the position where the fan is prone to generate separation vortexes, forming an air inlet slot. Since there is a pressure difference between the internal blade tip high-speed area and the outside of the base, the airflow is affected by the internal blade tip high-speed area, so that the intake air has a certain amount of energy. The airflow flowing into the air inlet slot is deeply mixed with the airflow in the mainstream high-speed area, balancing the internal pressure gradient, delaying the separation of the upper cover boundary layer, and greatly weakening the energy and shape of the separation vortex, which not only improves the aerodynamic efficiency but also reduces the vortex noise. In addition, the intake air compensates for the pressure difference at the tongue mouth to a certain extent, reduces the pressure gradient at the tongue mouth, and effectively reduces the aerodynamic noise.

[0030] Example 2

[0031] This embodiment, based on Example 1, is limited to a single-outlet centrifugal fan and describes the dimensional parameters of the air inlet slot. The radius of inner arc line 11 is designed to be between 1mm and 2mm from the blade tip, with a radius of 30mm to 31mm. At the high-speed exit of the blade tip, air from the wall immediately flows in through the orifice to balance the pressure in the high-speed zone at the blade tip. If the radius of inner arc line 11 is too small, the airflow will be directly sucked into the fan blade, failing to balance the outlet pressure. If the radius of inner arc line 11 is too large, the airflow at the upper cover will begin to flow into the high-speed zone, and a separation vortex will begin to form. The radius of outer arc line 12 is designed to be between 1.5mm and 3mm from the blade tip. If the radius of inner arc line 11 is 30mm, the radius of outer arc line 12 is 30.5mm to 31.5mm. If the radius of arc line 1 is 31mm, the radius of outer arc line 12 is 31.5mm to 32.5mm. If the radius of outer arc line 12 is too small, the slot gap is too small, the air intake velocity is too high, and the airflow shears the orifice, potentially producing a sharp sound. In the present invention, the inner arc 11, outer arc 12, first straight line 13, and second straight line 14 are all chamfered with an R angle of 0.2 mm. This R angle allows for smooth air intake without affecting overall sound quality. If the radius of the outer arc 12 is too large, the air intake hole is large, and the hole is far from the high-speed zone at the blade tip inside the frame, the external airflow energy will be too low, resulting in an excessively low air intake velocity, which may cause separation at the base outlet, failing to balance pressure and eliminate vortices. Furthermore, the distance between the inner arc 11 and the outer arc 12 is set to 0.5 mm to 1.5 mm, and in this embodiment, is preferably 0.7 mm.

[0032] Example 3

[0033] The difference between this embodiment and embodiment 2 is that it is limited to dual-outlet centrifugal fans. Figure 9 As shown, the position of the air inlet slot 1 is similar to that in embodiment 2. Figure 8As shown, the design of the air inlet slot 1 on the base has the same excellent performance in the double air outlet, which not only effectively weakens the backflow at the outlet wall and reduces eddy current noise, but also greatly improves the aerodynamic efficiency.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-performance centrifugal fan, characterized in that: The invention comprises an upper cover, a fan blade and a base, wherein a main air outlet is formed between the ends of the upper cover and the base, an air inlet slot (1) is provided on the base, the air inlet slot (1) is located between the fan blade and the main air outlet, the air inlet slot (1) is an arc-shaped structure, the air inlet slot (1) comprises an inner arc line (11) and an outer arc line (12), the inner arc line (11) and the outer arc line (12) both take the center of the fan blade as the center of the circle, the distance between the inner arc line (11) and the center of the fan blade is smaller than the distance between the outer arc line (12) and the center of the fan blade, the end of the inner arc line (11) and the end of the outer arc line (12) are connected by a first straight line (13) and a second straight line (14) of equal length, the first straight line (13) and the second straight line (14) are arranged in parallel and are both perpendicular to the plane where the main air outlet is located, and the first straight line (13) and the second straight line (14) are located between the tongue position and the position where the air flow is blown out vertically.

2. The high-performance centrifugal fan according to claim 1, characterized in that: The inner arc line (11) is 1 to 2 mm away from the tip of the fan blade.

3. The high-performance centrifugal fan according to claim 1, wherein: The outer arc line (12) is 1.5 to 3 mm away from the tip of the fan blade.

4. The high-performance centrifugal fan according to claim 1, wherein: The distance between the inner arc line (11) and the outer arc line (12) is 0.5-1.5 mm.

5. The high-performance centrifugal fan according to claim 1, characterized in that: The inner arc line (11), the outer arc line (12), the first straight line (13) and the second straight line (14) are all subjected to R-angle chamfering.

6. The high-performance centrifugal fan according to claim 2, characterized in that: The inner arc line (11) is 1.2 to 1.8 mm away from the tip of the fan blade.

7. The high-performance centrifugal fan according to claim 3, characterized in that: The outer arc line (12) is 2.0-2.5 mm away from the tip of the fan blade.

8. The high-performance centrifugal fan according to claim 1, characterized in that: The centrifugal fan has a single air outlet or a double air outlet.

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