Pressure coupling type centrifugal fan

Abstract

The invention discloses a pressure coupling type centrifugal fan, which belongs to the technical field of centrifugal fan structure improvement and comprises a volute, an upper cover and a base are arranged on the upper surface and the lower surface of the volute respectively, fan blades are arranged in the volute, and a volute tongue is arranged at an outlet of the volute. The volute tongue is designed in a non-straight cylinder mode in the volute thickness direction according to different volute tongue area pressure intensity distribution curves. Specifically, the volute tongue is designed in a forward pressure mode based on a pressure distribution curve, the volute tongue is designed in a reverse pressure mode based on the pressure distribution curve, or an area, with the pressure not lower than a pressure set value, on the volute tongue is designed in a local inclined mode. A traditional straight barrel type volute tongue is improved, the volute tongue can adapt to the pressure distribution characteristics of the needle volute tongue, and fan noise generated in the using process is reduced.

Description

Technical Field

[0001] The invention relates to a pressure-coupled centrifugal fan, belonging to the technical field of centrifugal fan structure improvement. Background Art

[0002] Centrifugal fans are often used to meet the heat dissipation needs of electronic equipment, computers, and industrial machines. They are usually driven by an electric motor, which draws in air and generates airflow through rotating fan blades. This airflow can carry heat and increase air circulation. With its efficient air flow ability, it can quickly remove heat, thereby protecting the stable operation of the equipment. During operation, the centrifugal fan currently used drives the impeller to rotate through the motor to do positive work on the airflow to increase its pressure. The airflow flows in from the axial inlet, flows through the volute tongue, and flows out from the radial outlet. The noise generated during operation is relatively large, and even sharp or harsh sounds are produced. The high-speed airflow thrown out by the fan blades and the action of the volute tongue are the main aerodynamic noise. Therefore, the large noise during use may have a bad effect.

[0003] The pulsating pressure near the volute tongue is the main source of noise. The straight-cylinder tongue of the traditional centrifugal fan is not conducive to the flow of gas in the volute in the z direction (the thickness direction of the centrifugal fan) because the direction and speed of the fluid in the z direction are different. In addition, the fluid hits the volute tongue at the same time, which will form a strong fan fundamental frequency noise. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a pressure-coupled centrifugal fan, which improves the traditional straight-cylinder volute tongue, can adapt to the pressure distribution characteristics of the needle volute tongue, and reduce the fan noise generated during use.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A pressure-coupled centrifugal fan comprises a volute, wherein an upper cover and a base are respectively arranged on the upper and lower sides of the volute, fan blades are arranged inside the volute, and a volute tongue is arranged at the outlet of the volute. The volute tongue is designed in a non-straight-cylinder style along the thickness direction of the volute according to different pressure distribution curves in the volute tongue area.

[0007] The volute tongue is designed for pressure following the pressure distribution curve, the middle of the volute tongue with the maximum pressure is closest to the fan blade, and the distance between the volute tongue and the fan blade increases gradually from the middle position to both sides.

[0008] The fluctuation of the distance between the volute tongue and the fan blade is regulated by the fluctuation constant A.

[0009] The volute tongue is designed for reverse pressure based on a pressure distribution curve, the middle of the volute tongue with the maximum pressure is farthest from the fan blade, and the distance between the volute tongue and the fan blade tends to gradually decrease from the middle position to both sides.

[0010] The fluctuation of the distance between the volute tongue and the fan blade is regulated by the fluctuation constant B.

[0011] The area on the volute tongue where the pressure is not lower than the pressure setting value is designed to be locally inclined, and along the direction from the upper cover to the base, the distance between the volute tongue and the fan blade gradually decreases, and the area on the volute tongue where the pressure is lower than the pressure setting value is designed to be straight.

[0012] The fluctuation of the distance between the volute tongue and the fan blade is regulated by the fluctuation constant C.

[0013] The pressure setting value is 80% of the maximum value of the snail tongue pressure.

[0014] Beneficial effects of the invention: The invention provides a pressure-coupled centrifugal fan, which improves the traditional straight-cylinder volute tongue, can adapt to the pressure distribution characteristics of the needle volute tongue, and reduce the fan noise generated during use;

[0015] The volute tongue is designed with a pressure-following design based on the pressure distribution curve, so that the part of the volute tongue that is under the greatest pressure is close to the fan. Due to the large curvature of this part, it will not significantly increase the noise and play a role in diverting and diverting the airflow, directing the airflow to the groove away from the fan to balance the pressure distribution, thereby reducing the overall noise;

[0016] The volute tongue is designed with reverse pressure based on the pressure distribution curve, so that the part of the volute tongue with the greatest pressure is far away from the impeller, which reduces the intensity of the pulsation force and reduces the noise to a certain extent. At the same time, the part with lower pressure is close to the fan, ensuring that the average distance between the volute tongue and the impeller does not change significantly.

[0017] The area on the volute tongue where the pressure is not lower than the pressure setting value is designed with a local tilt to avoid the airflow hitting the volute tongue at the same time. At the same time, the distance from the fan gradually increases along the thickness direction of the centrifugal fan to ensure the convenience of the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the centrifugal fan of the present invention;

[0019] Figure 2 Fig. 2 is the distribution curve of the snail tongue pressure along the Z direction;

[0020] Figure 3 The straight-tube volute tongue (a), the forward pressure volute tongue (b), the reverse pressure volute tongue (c) and the partially inclined volute tongue (d) in the present invention correspond to Figure 1 Schematic diagram of the cross-sectional structure in the direction vertical to the air outlet;

[0021] Figure 4 It is a schematic diagram of the pressure distribution of the straight-tube volute tongue along the thickness direction of the volute in the present invention;

[0022] Figure 5 It is a schematic diagram of the pressure distribution of the pressure-type volute tongue along the thickness direction of the volute in the present invention;

[0023] Figure 6 It is a schematic diagram of the pressure distribution of the reverse pressure type volute tongue along the thickness direction of the volute in the present invention;

[0024] Figure 7 It is a schematic diagram of the pressure distribution of the partially inclined volute tongue along the thickness direction of the volute in the present invention;

[0025] Figure 8 A diagram of a method for drawing a directional pressure-type volute tongue in the present invention;

[0026] The reference numerals in the figure are as follows: 1-volute; 2-upper cover; 3-base; 4-fan blades; 5-volute tongue. DETAILED DESCRIPTION

[0027] 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 protection scope of the present invention.

[0028] Example 1

[0029] like Figure 1 As shown, the pressure-coupled centrifugal fan comprises a volute 1, an upper cover 2 and a base 3 are respectively arranged on the upper and lower sides of the volute 1, a fan blade 4 is arranged inside the volute 1, and a volute tongue 5 is arranged at the outlet of the volute 1. The z direction is the thickness direction of the volute 1. Figure 2 As shown in the figure, the intensity of the pulsating pressure in the tongue area in the z direction (positive z represents close to the base 3, negative z represents close to the upper cover 2) is inconsistent, which is manifested as a large pressure difference in the tongue area. The pressure at the point where the curvature of the tongue is the largest (tangent at the vertex) is extracted and a curve is drawn along the Z direction. It is found that the pressure on both sides is small and the pressure in the middle is large. Figure 3 As shown in (a), the existing volute tongue structure adopts a straight-tube design, such as Figure 4 As shown, the vortex in the volute tongue area of ​​the traditional straight-cylinder centrifugal fan is larger.

[0030] The present invention improves the structure of the volute tongue 5, and the volute tongue 5 is designed as a non-straight cylinder along the thickness direction of the volute 1 according to the different pressure distribution curves of the volute tongue area. Figure 3As shown in (b), the volute tongue 5 is designed to follow the pressure distribution curve. The undulation shape of the volute tongue is consistent with the shape of the pressure curve and is regulated by the undulation constant A. The larger A is, the greater the volute tongue undulation is. The point in the middle of the volute tongue where the pressure is the highest is closest to the fan blades, and the distance between the volute tongue and the fan blades gradually increases from the middle position to both sides. This design makes the part of the volute tongue that is subject to the greatest pressure close to the fan. Since this part has a large curvature, it will not significantly increase the noise and will play a role in guiding and diverting the airflow, directing the airflow to the groove away from the fan to balance the pressure distribution, thereby reducing the overall noise. Figure 5 As shown, the forward pressure volute tongue increases the pressure near the air inlet of the upper cover 2, making the pressure stable, which is beneficial to reducing the vortex in the volute tongue area.

[0031] like Figure 8 As shown, 7 planes are cut out along the z direction and their positions correspond to the peak positions of the pressure distribution, and the arc line of the volute tongue on each plane is controlled separately.

[0032] Example 2

[0033] like Figure 1 As shown, the pressure-coupled centrifugal fan comprises a volute 1, an upper cover 2 and a base 3 are respectively arranged on the upper and lower sides of the volute 1, a fan blade 4 is arranged inside the volute 1, and a volute tongue 5 is arranged at the outlet of the volute 1. The z direction is the thickness direction of the volute 1. Figure 2 As shown in the figure, the intensity of the pulsating pressure in the tongue area in the z direction (positive z represents close to the base 3, negative z represents close to the upper cover 2) is inconsistent, which is manifested as a large pressure difference in the tongue area. The pressure at the point where the curvature of the tongue is the largest (tangent at the vertex) is extracted and a curve is drawn along the Z direction. It is found that the pressure on both sides is small and the pressure in the middle is large. Figure 3 As shown in (a), the existing volute tongue structure adopts a straight-tube design, such as Figure 4 As shown, the vortex in the volute tongue area of ​​the traditional straight-cylinder centrifugal fan is larger.

[0034] The present invention improves the structure of the volute tongue 5, and the volute tongue 5 is designed as a non-straight cylinder along the thickness direction of the volute 1 according to the different pressure distribution curves of the volute tongue area. Figure 3 As shown in (c), the volute tongue 5 is designed in reverse pressure based on the pressure distribution curve. The distance between the volute tongue and the fan blade is the farthest from the middle position where the pressure is the highest. The distance between the volute tongue and the fan blade gradually decreases from the middle position to both sides. The undulation shape of the volute tongue is opposite to the shape of the pressure curve and is regulated by the undulation constant B. This design makes the part of the volute tongue with the greatest pressure away from the impeller, which reduces the intensity of the pulsation force and reduces noise to a certain extent. At the same time, the part with lower pressure is close to the fan, ensuring that the average distance between the volute tongue and the impeller does not change significantly. Figure 6As shown in the figure, the reverse pressure volute tongue greatly reduces the extreme pressure at the volute tongue, from 81Pa to 68Pa, and the minimum pressure is reduced from 43Pa to 33Pa, which to a certain extent reflects the reduction in the intensity of the interaction between the pulsating flow and the volute tongue.

[0035] Example 3

[0036] like Figure 1 As shown, the pressure-coupled centrifugal fan comprises a volute 1, an upper cover 2 and a base 3 are respectively arranged on the upper and lower sides of the volute 1, a fan blade 4 is arranged inside the volute 1, and a volute tongue 5 is arranged at the outlet of the volute 1. The z direction is the thickness direction of the volute 1. Figure 2 As shown in the figure, the intensity of the pulsating pressure in the tongue area in the z direction (positive z represents close to the base 3, negative z represents close to the upper cover 2) is inconsistent, which is manifested as a large pressure difference in the tongue area. The pressure at the point where the curvature of the tongue is the largest (tangent at the vertex) is extracted and a curve is drawn along the Z direction. It is found that the pressure on both sides is small and the pressure in the middle is large. Figure 3 As shown in (a), the existing volute tongue structure adopts a straight-tube design, such as Figure 4 As shown, the vortex in the volute tongue area of ​​the traditional straight-cylinder centrifugal fan is larger.

[0037] The present invention improves the structure of the volute tongue 5, and the volute tongue 5 is designed as a non-straight cylinder along the thickness direction of the volute 1 according to the different pressure distribution curves of the volute tongue area. Figure 3 As shown in (d), the volute tongue 5 is designed with a local inclined design based on the pressure distribution curve. Along the direction from the upper cover to the base, the distance between the volute tongue and the fan blade gradually decreases, and the fluctuation of the distance between the volute tongue and the fan blade is regulated by the fluctuation constant C. The area on the volute tongue where the pressure is lower than the pressure setting value is designed as a straight cylinder. Taking 80% of the maximum volute tongue pressure as the baseline, the 80%-100% area is circled for an inclined design, and the rest of the part maintains the traditional straight cylinder design. This structural design prevents the airflow from hitting the volute tongue at the same time, and at the same time, the distance from the fan gradually increases along the z direction to ensure the convenience of the process. As shown in Figure 7 As shown, the partially inclined volute tongue has a similar function to the reverse pressure volute tongue, but has a simpler structure and is easier to process.

[0038] The above are only preferred embodiments 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 pressure-coupled centrifugal fan, characterized in that: The invention comprises a volute (1), wherein an upper cover (2) and a base (3) are respectively arranged on the upper and lower sides of the volute (1), a fan blade (4) is arranged inside the volute (1), and a volute tongue (5) is arranged at the outlet of the volute (1), and the volute tongue (5) is designed in a non-straight-cylinder manner along the thickness direction of the volute (1) according to different pressure distribution curves in the volute tongue area.

2. A pressure-coupled centrifugal fan according to claim 1, characterized in that: The volute tongue (5) is designed for pressure following the pressure distribution curve, the distance between the middle of the volute tongue (5) where the pressure is the highest and the fan blade (4) is the shortest, and the distance between the volute tongue (5) and the fan blade (4) tends to gradually increase from the middle position to both sides.

3. The pressure-coupled centrifugal fan according to claim 2, characterized in that: The fluctuation of the distance between the volute tongue (5) and the fan blade (4) is regulated by the fluctuation constant A.

4. The pressure-coupled centrifugal fan according to claim 1, characterized in that: The volute tongue (5) is designed for reverse pressure based on a pressure distribution curve; the distance between the middle of the volute tongue (5) where the pressure is maximum and the fan blade (4) is the farthest; and the distance between the volute tongue (5) and the fan blade (4) tends to gradually decrease from the middle position to both sides.

5. The pressure-coupled centrifugal fan according to claim 4, characterized in that: The fluctuation of the distance between the volute tongue (5) and the fan blade (4) is regulated by the fluctuation constant B.

6. The pressure-coupled centrifugal fan according to claim 1, characterized in that: The area on the volute tongue (5) where the pressure is not lower than the pressure setting value is designed to be locally inclined, and along the direction from the upper cover (2) to the base (3), the distance between the volute tongue (5) and the fan blade (4) gradually decreases, and the area on the volute tongue (5) where the pressure is lower than the pressure setting value is designed to be straight.

7. The pressure-coupled centrifugal fan according to claim 6, characterized in that: The fluctuation of the distance between the volute tongue (5) and the fan blade (4) is regulated by the fluctuation constant C.

8. The pressure-coupled centrifugal fan according to claim 6, characterized in that: The pressure setting value is 80% of the maximum value of the snail tongue pressure.

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