Centrifugal fan structure and design method thereof

Abstract

The invention relates to a centrifugal fan structure and a design method thereof, the centrifugal fan structure comprises a volute and a rotating impeller arranged in the volute, an air inlet is formed in the upper side face of the volute, and an air outlet channel is formed in the arc-shaped face of the volute; the upper top wall of the air outlet channel is an inclined wall; the rotating impeller comprises an impeller body and fins; the impeller body is cylindrical, and a plurality of fins are attached to the cylindrical surface of the impeller body in the circumferential direction. The wing panel is divided into an upper wing and a lower wing; the upper wing and the lower wing are respectively close to the air inlet and the air outlet channel; the lower wing is only bent to be in a wing groove shape, and the upper wing is bent to be in a wing groove shape and is bent downwards; when the rotating impeller rotates, the upper wing compresses air at the air inlet towards the lower part of the volute; and the air compressed to the lower part flows along the plane under the action of the lower wing and is exhausted from the air outlet channel. The impeller has the beneficial effects that the air inlet amount is increased, the bearing capacity of the impeller body can be improved, large air flow is achieved at the bottom wall of the air outlet channel, and the heat dissipation effect is good.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal fans, and in particular to a centrifugal fan structure and a design method thereof. Background Art

[0002] In the existing multi-blade volute fan, Figure 5 , Figure 6 , Figure 7 and Fig. 9 As shown in the figure: a. The inner and outer edges of the wing are parallel to the axis, and the wing grooves formed are also parallel to the axis. When the impeller rotates, it can only generate wind direction in the plane direction, and will not press the air flow from top to bottom. This method causes the air volume at the air outlet channel to be insufficient; b. There is a disc at the bottom of the impeller, which has a certain thickness and thus occupies a certain space, so the air volume of the air outlet channel near the bottom wall will be weakened - such as Fig. 9 c. In addition, since the upper wall of the existing air outlet channel is inclined, it will block part of the air volume, which will cause air to flow back (such as Fig. 9 There is a part of air reflux), so that the air volume at the outlet of the air outlet channel is very small; d. Since the wing is set on the disc, the wing is very easy to deform, thereby reducing the ability to compress air.

[0003] When using a fan to cool the heat source, Fig.11 As shown, the heat source is usually located in the same plane as the bottom wall of the air outlet channel, which results in that the heat source cannot be cooled well.

[0004] Based on this, our company has made improvements on the traditional multi-blade centrifugal volute fan to overcome the above problems. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a centrifugal fan structure and a design method thereof which increases the air intake, can improve the bearing capacity of the impeller body, has a larger air flow at the bottom wall of the air outlet channel, and has a good heat dissipation effect.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] In a first aspect, a centrifugal fan structure includes a volute and a rotating impeller disposed therein, wherein the upper side of the volute has an air inlet, and the arc surface of the volute is provided with an air outlet channel; the upper top wall of the air outlet channel is an inclined wall, and the lower bottom plate is a plane wall, so that the channel opening of the air outlet channel gradually narrows along the air outlet direction;

[0008] The rotating impeller comprises an impeller body and vanes; the impeller body is cylindrical, and a plurality of vanes are circumferentially arranged on the cylindrical surface;

[0009] The wing is divided into an upper wing and a lower wing, and the upper wing and the lower wing are respectively close to the air inlet and the air outlet; the lower wing is only bent into a wing groove shape, that is, it is a curved straight line after plane projection, and the upper wing is bent into a wing groove shape and bent downward, that is, it is a shadow area after plane projection;

[0010] When the impeller rotates, the upper wing compresses the air at the air inlet toward the lower part of the volute; the air compressed to the lower part flows along the plane under the action of the lower wing and is discharged from the air outlet channel.

[0011] As a preferred technical solution of the present application, the inner edge of the blade is parallel to the axis of the impeller body, and the inner edge is in contact with the cylindrical surface of the impeller body; the back side of the blade forms an acute angle with the cylindrical surface of the impeller body; the outer edge of the blade is parallel to the axis of the impeller body, and the outer edge is bent toward the front side of the blade to form a wing groove shape.

[0012] As a preferred technical solution of the present application, the diameter of the air inlet is consistent with the outer diameter of the rotating impeller.

[0013] As a preferred technical solution of the present application, the width of the wing at each upper and lower position is consistent.

[0014] As a preferred technical solution of the present application, the upper portion of the wing has a notch near the cylindrical surface.

[0015] Second, the design method of the centrifugal fan structure includes the following methods:

[0016] A rectangular original plate is placed vertically, one of its vertical edges remains unchanged, and the other vertical edge is bent toward the front of the rectangular original plate to form a wing groove shape; the upper edge of the plate forming the wing groove shape is bent toward the front of the plate to form a downward pressure groove shape; after the bending is completed, the plate portion forming the downward pressure groove is the upper wing, and the plate portion with only the wing groove at the bottom is the lower wing;

[0017] The edge that remains unchanged is defined as the inner edge, and the vertical edge that bends toward the front of the rectangular original plate is defined as the outer edge; the edge side of the inner edge is a curved surface, and the inner edge is attached to the cylindrical surface of the impeller body and fixed by welding; in this way, a plurality of blades are evenly fixedly installed on the circumference of the cylindrical surface of the impeller body;

[0018] The rotating impeller is installed in the volute; and the upper wing is required to press the air at the air inlet to the annular area between the impeller body and the arc-shaped wall of the volute, and the lower wing can blow the air in the annular area outward along the plane, so that the air flows outward along the air outlet channel;

[0019] When the air in the quasi-annular area flows to the air outlet channel, it is guided by the inclined wall of the upper top wall of the air outlet channel; the intersection of the surface where the inclined wall of the upper top wall of the air outlet channel is located and the surface where the lower bottom wall is located is where the heat dissipation part needs to be placed.

[0020] As a preferred technical solution of the present application, the air outlet channel also has a left wall and a right wall, the left wall is tangent to the circle of the edge of the volute, and the right wall gradually expands outward along the air outlet direction of the air outlet channel.

[0021] The present invention has the following advantages:

[0022] In the existing fans: a. When the traditional vanes are working, they can only transport the air inside the volute to the air outlet channel - that is, the vanes only allow the air to flow in the plane. When the air in the volute is extracted, negative pressure will be formed inside, so the outside air enters the volute under the action of negative pressure. This method has a small flow rate; b. In addition, the traditional vanes are arranged on a disc - the lower end of the vane is fixedly connected to the circle, and the inner edge of the vane is spaced from the impeller body; this causes the vanes to be easily deformed when transporting air, and it is difficult to increase the air volume by increasing the speed of the impeller body; c. In addition, the disc has a certain thickness, resulting in a small air flow rate near the bottom wall of the air outlet channel corresponding to the position of the disc, and it is impossible to dissipate heat for the heat source components placed on the same plane as the bottom wall of the air outlet channel;

[0023] In this scheme: a. The structure of the wing itself is changed to increase the air volume at the outlet of the air outlet. Specifically, the upper wing of the wing is bent downward. When working, the air at the air inlet can be compressed to the position of the lower wing under the action of the upper wing, and then the compressed air is transported to the air outlet in the plane under the action of the lower wing. It is equivalent to the upper wing actively compressing the air at the air inlet, rather than relying solely on negative pressure as traditionally. Therefore, the amount of air entering the air inlet of this scheme is larger; b. In this scheme, the inner edge of the wing is directly fixed on the cylindrical surface of the impeller body, so it can withstand a greater air reaction force, so that the fan of this scheme can increase the air volume by increasing the speed of the impeller body; c. In this scheme, since no disc is set, there is air at the original disc position. Then, when the wing acts, the air at the original disc position can flow outward along the bottom wall of the air outlet channel, which can better cool the heat source placed at the bottom wall of the air outlet channel;

[0024] In summary, this solution increases the air intake volume, can increase the speed of the impeller body to increase the air output volume, and there is also a large air flow at the bottom wall of the air outlet channel; therefore, the fan heat dissipation effect of this solution is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 It is a structural schematic diagram of another angle of the present invention;

[0027] Figure 3 is a schematic diagram of the structure of the rotating impeller;

[0028] Figure 4 It is a schematic diagram of the structure of a rotating impeller with notches on the wings;

[0029] Figure 5 It is a structural schematic diagram of a rotating impeller in the prior art;

[0030] Figure 6 It is a structural schematic diagram of a fan in the prior art;

[0031] Figure 7 A simulation diagram of the deformation of the blades of a rotating impeller in the prior art when rotating;

[0032] Figure 8 A simulation diagram of the deformation of the blades of the rotating impeller of the present invention during rotation;

[0033] Fig. 9 It is a simulation diagram of the air outlet at the air outlet channel of the prior art;

[0034] Fig.10 A simulation diagram of the air outlet at the air outlet channel of the present invention;

[0035] Fig.11 A schematic diagram of the position between the fan and the heat source;

[0036] In the figure: 10-volute, 11-air inlet, 12-air outlet channel, 1201-upper top wall;

[0037] 20-rotating impeller, 21-impeller body, 22-wing blade, 2201-upper wing, 2202-lower wing, 2203-notch. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0039] It should be noted that the directions or positional relationships indicated by "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use, or are the directions or positional relationships commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0040] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with those in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as here.

[0041] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions in the embodiments may be combined with each other.

[0042] This embodiment discloses a centrifugal fan structure, such as Figure 1 to Figure 3 As shown, it includes a volute 10 and a rotating impeller 20, and the rotating impeller 20 is rotatably arranged in the volute 10; an air inlet 11 is provided on the upper side of the volute 10; an air outlet channel 12 is provided at the arc surface of the volute 10, and the upper top wall 1201 of the air outlet channel 12 is an inclined wall, and the lower bottom plate is a plane wall, so that the channel opening of the air outlet channel 12 gradually narrows along the air outlet direction; in addition, the air outlet channel 12 also has a left wall and a right wall, the left wall is tangent to the circle of the edge of the volute 10, and the right wall gradually expands outward along the air outlet direction of the air outlet channel 12;

[0043] The rotating impeller 20 includes an impeller body 21 and fins 22; the impeller body 21 is cylindrical, and a plurality of fins 22 are circumferentially arranged on the cylindrical surface; the fins 22 are divided into an upper wing 2201 and a lower wing 2202, and the upper wing 2201 and the lower wing 2202 are respectively close to the air inlet 11 and the air outlet channel 12; the lower wing 2202 is only bent into a wing groove shape, that is, it is a curved straight line after plane projection, and the upper wing 2201 is both bent into a wing groove shape and bent downward, that is, it is a shadow area when projected on the plane;

[0044] When the impeller 20 rotates, the upper wing 2201 will compress the air inlet 11, so that the air there is compressed to the lower part of the volute 10 - that is, compressed to the lower wing 2202; then the air compressed to the lower part flows along the plane under the action of the lower wing 2202 and is discharged from the air outlet channel 12; corresponding to the traditional fan with only the working mode of the lower wing of this scheme, at the same speed, the active compression method of the upper wing 2201 of this scheme can allow more air to enter the air inlet 11, thereby increasing the air volume at the air outlet channel 12.

[0045] See also Figure 3In this embodiment, the wing 22 is further designed; specifically, the inner edge of the wing 22 is parallel to the axis of the impeller body 21, and the inner edge is in contact with the cylindrical surface of the impeller body 21; the back of the wing 22 forms an acute angle with the cylindrical surface of the impeller body 21; the outer edge of the wing 22 is parallel to the axis of the impeller body 21, and the outer edge is bent toward the front of the wing 22, thereby forming a wing groove shape.

[0046] In this embodiment, the diameter of the air inlet 11 is consistent with the outer diameter of the rotating impeller 21. This approach can maximize the air inlet area.

[0047] In this embodiment, refer to Figure 3 , the width of the wing 22 at each position above and below is consistent. Figure 4 The upper portion of the wing 22 has a notch 2203 near the cylindrical surface.

[0048] This embodiment also discloses a design method of a centrifugal fan structure, including the following methods:

[0049] A rectangular original plate is placed vertically, one of its vertical edges remains unchanged, and the other vertical edge is bent toward the front of the rectangular original plate to form a wing groove shape; the upper edge of the plate forming the wing groove shape is bent toward the front of the plate to form a downward pressing groove shape; after the bending is completed, the plate portion forming the downward pressing groove is the upper wing 2201, and the plate portion with only the wing groove at the bottom is the lower wing 2202;

[0050] The edge that remains unchanged is defined as the inner edge, and the vertical edge that bends toward the front of the rectangular original plate is defined as the outer edge; the edge side of the inner edge is an arc surface, and the inner edge is attached to the cylindrical surface of the impeller body 21 and fixed by welding; in this way, a plurality of vanes 22 are evenly fixedly installed on the circumference of the cylindrical surface of the impeller body 21;

[0051] The rotating impeller 20 is installed in the volute 10; and the upper wing 2201 is required to press the air at the air inlet 2203 to the annular area between the impeller body 21 and the arc-shaped wall of the volute 10, and the lower wing 2202 is required to blow the air in the annular area outward along the plane, so that the air flows outward along the air outlet channel 12;

[0052] When the air in the quasi-annular area flows to the air outlet channel 12, it is guided by the inclined wall of the upper top wall of the air outlet channel 12; the intersection of the surface where the inclined wall of the upper top wall of the air outlet channel 12 is located and the surface where the lower bottom wall is located is where the heat dissipation part needs to be placed.

[0053] Experimental Example 1

[0054] The fan with the blade structure of this scheme is now compared with the fan with the traditional blade structure. The experimental results are as follows:

[0055] 1. At the same speed, the air volume of the fan in this solution increases by about 11%, and the maximum static pressure increases by about 5%;

[0056] 2. Figure 7 and Figure 8 As shown, the overall deformation of the blades in this solution is reduced by one order of magnitude compared with the previous one; this is because the vanes are directly arranged on the impeller body, which improves the strength; in this way, the air volume can be increased by increasing the rotation speed;

[0057] 3. Fig. 9 and Fig.10 As shown, the total air volume of the prior art is smaller than that of the present solution, and the present solution can press the air downward, so that the velocity vector field at the outlet of the multi-blade centrifugal volute fan is biased downward, which is beneficial to the heat dissipation of the heat source placed at the bottom of the air outlet or other parts that need to be cooled.

[0058] The above embodiments only express preferred implementation modes, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A centrifugal fan structure, comprising a volute (10) and a rotating impeller (20) arranged therein, wherein the upper side surface of the volute (10) is provided with an air inlet (11), and an air outlet channel (12) is arranged at the arc surface of the volute (10); the upper top wall (1201) of the air outlet channel (12) is an inclined wall, and the lower bottom plate is a plane wall, so that the channel opening of the air outlet channel (12) gradually decreases along the air outlet direction; the characteristics are: The rotating impeller (20) comprises an impeller body (21) and vanes (22); the impeller body (21) is cylindrical, and a plurality of vanes (22) are circumferentially arranged on the cylindrical surface; The wing (22) is divided into an upper wing (2201) and a lower wing (2202), wherein the upper wing (2201) and the lower wing (2202) are respectively close to the air inlet (11) and the air outlet channel (12); the lower wing (2202) is only bent into a wing groove shape, that is, it is a curved straight line after plane projection, and the upper wing (2201) is both bent into a wing groove shape and bent downward, that is, it is a shadow area after plane projection; When the impeller (20) rotates, the upper wing (2201) compresses the air at the air inlet (11) toward the lower part of the volute (10); the air compressed to the lower part flows along the plane under the action of the lower wing (2202) and is discharged from the air outlet channel (12).

2. A centrifugal fan structure and design method thereof according to claim 1, characterized in that: The inner edge of the wing (22) is parallel to the axis of the impeller body (21), and the inner edge is in contact with the cylindrical surface of the impeller body (21); The back surface of the wing (22) forms an acute angle with the cylindrical surface of the impeller body (21); The outer edge of the wing (22) is parallel to the axis of the impeller body (21), and the outer edge is bent toward the front side of the wing (22) to form a wing groove shape.

3. A centrifugal fan structure and design method thereof according to claim 1, characterized in that: The diameter of the air inlet (11) is consistent with the outer diameter of the rotating impeller (21).

4. A centrifugal fan structure and design method thereof according to claim 2, characterized in that: The wing (22) has the same width at each upper and lower position.

5. A centrifugal fan structure and design method thereof according to claim 2, characterized in that: The upper part of the wing (22) is provided with a notch (2203) near the cylindrical surface.

6. A method for designing a centrifugal fan structure as described in any one of claims 1 to 5, characterized in that: Including the following methods: A rectangular original plate is placed vertically, one vertical edge of which remains unchanged, and the other vertical edge of which is bent toward the front of the rectangular original plate to form a wing groove shape; the upper edge of the plate forming the wing groove shape is bent toward the front of the plate to form a downward pressing groove shape; After the bending is completed, the plate portion with the lower pressure groove formed is the upper wing (2201), and the plate portion with only the wing groove at the bottom is the lower wing (2202); The edge that remains unchanged in position is defined as the inner edge, and the vertical edge that bends toward the front of the rectangular original plate is defined as the outer edge; the edge side of the inner edge is an arc-shaped surface, and the inner edge is attached to the cylindrical surface of the impeller body (21) and fixed by welding; thus, a plurality of vanes (22) are evenly fixedly installed in the circumferential direction of the cylindrical surface of the impeller body (21); The rotating impeller (20) is installed in the volute (10); and the upper wing (2201) is required to press the air at the air inlet (2203) to the quasi-annular area between the impeller body (21) and the arc-shaped wall of the volute (10), and the lower wing (2202) is required to blow the air in the quasi-annular area outward along the plane, so that the air flows outward along the air outlet channel (12); When the air in the quasi-annular area flows to the air outlet channel (12), it is guided by the inclined wall of the upper top wall (1201) of the air outlet channel (12); the intersection of the surface where the inclined wall of the upper top wall of the air outlet channel (12) is located and the surface where the lower bottom wall is located is the place where the heat dissipation part needs to be placed.

7. The design method of the centrifugal fan structure according to claim 6, characterized in that: The air outlet channel (12) further comprises a left wall and a right wall, wherein the left wall is tangent to the circle of the edge of the volute (10), and the right wall gradually expands outwards along the air outlet direction of the air outlet channel (12).

Images