CN112983862A

CN112983862A - Centrifugal fan

Info

Publication number: CN112983862A
Application number: CN202110254105.XA
Authority: CN
Inventors: 康钊; 王冰; 宋强
Original assignee: Qingdao Haier Air Conditioner Gen Corp Ltd; Qingdao Haier Air Conditioning Electric Co Ltd; Haier Smart Home Co Ltd
Current assignee: Qingdao Haier Air Conditioner Gen Corp Ltd; Qingdao Haier Air Conditioning Electric Co Ltd; Haier Smart Home Co Ltd
Priority date: 2021-03-04
Filing date: 2021-03-04
Publication date: 2021-06-18

Abstract

The invention belongs to the technical field of centrifugal fans, and particularly provides a centrifugal fan. The invention aims to solve the problem that the existing centrifugal fan is too loud in noise. For this purpose, the centrifugal fan comprises fan blades which are in a bent plate shape, the fan blades are provided with a centripetal surface and a vest surface, the tail edges of the fan blades are provided with grooves, and the size of the openings of the grooves gradually shrinks towards the bottom ends. The air flow vortex group is more stably transited by arranging the groove at the tail edge of the fan blade, excessive loss of air volume caused by larger angles of other triangular or polygonal groove structures can be avoided, and a certain noise reduction effect can be achieved. On this basis, the recess has the effect of luring the air current by the convergent opening of opening to bottom, and the sectional area is crescent when the gas flow passes through here, and the dynamic pressure reduces, and the static pressure increases, and the gas velocity of flow reduces, further reduces aerodynamic noise.

Description

Centrifugal fan

Technical Field

The invention belongs to the technical field of centrifugal fans, and particularly provides a centrifugal fan.

Background

With the improvement of life quality, the attention degree of consumers to the noise problem of the centrifugal fan is higher and higher, the noise problem of the centrifugal fan becomes the primary consideration factor for selecting the centrifugal fan or equipment provided with the centrifugal fan, and the use experience of users is greatly reduced due to the noise problem of the centrifugal fan. The centrifugal fan is an important part for converting input mechanical energy into gas potential energy and kinetic energy in fluid machinery, is visible everywhere in life of people and has high utilization rate. The noise of centrifugal fans has always been an important task for manufacturers to optimize centrifugal fans. The noise of the centrifugal fan mainly includes: mechanical noise, aerodynamic noise, and electromagnetic noise. With the improvement of machining precision and technological level, mechanical noise and electromagnetic noise are greatly improved, so that research on pneumatic noise becomes a hot spot. Most of the noise of the existing centrifugal fan comes from pneumatic noise, and the flow direction of the air flow is not easy to control, so that the noise of the centrifugal fan is not greatly improved, and the use experience of consumers is greatly reduced.

Accordingly, there is a need in the art for a new centrifugal fan that solves the problem of the existing centrifugal fan being too noisy.

Disclosure of Invention

In order to solve the above problems in the prior art, that is, to solve the problem of the centrifugal fan that the noise is too large, the present invention provides a centrifugal fan, which includes a fan blade, wherein the fan blade is in a curved plate shape, the fan blade has a centripetal surface and a vest surface, a groove is provided at a trailing edge of the fan blade, and the size of an opening of the groove gradually shrinks toward a bottom end.

In the preferable technical scheme of the centrifugal fan, the centripetal surface is a first arc line after intersecting with the inner surface of the groove, the vest surface is a second arc line after intersecting with the inner surface of the groove, and the opening size of the first arc line is larger than that of the second arc line.

In the above-mentioned centrifugal fan, preferably, the trailing edge of the fan blade is an inclined surface.

In a preferred embodiment of the centrifugal fan, the plurality of grooves are provided on the fan blade.

In the above preferred technical solution of the centrifugal fan, the centrifugal fan includes a fan frame, and the fan blades are uniformly arranged on the fan frame.

In a preferred embodiment of the centrifugal fan, the fan frame is cylindrical or elliptical.

In the above preferred technical solution of the centrifugal fan, the front edge of the fan blade is fixedly connected to the inner sidewall of the fan frame.

In a preferred embodiment of the centrifugal fan, the fan blades and the fan frame are integrally formed.

In a preferred embodiment of the centrifugal fan, the fan blades have a thickness gradually decreasing from the leading edge to the trailing edge.

In the preferable technical scheme of the centrifugal fan, the fan blade is provided with a cavity structure outside the groove, and the cavity structure is internally provided with a reinforcing rib.

The centrifugal fan in the technical scheme of the invention comprises fan blades, wherein the fan blades are in a bent plate shape, the fan blades are provided with a centripetal surface and a vest surface, the tail edges of the fan blades are provided with grooves, and the size of the openings of the grooves gradually shrinks towards the bottom end.

With the above arrangement, the centrifugal fan of the present invention has the curved plate-shaped fan blades, and the change in the direction of the air flow is gradually changed, and the curved plate-shaped fan blades reduce the instantaneous impact of the air flow on the fan blades, and the air flow pressure loss is reduced, whereby the pressure difference in the air flow passage is reduced, the turbulence intensity is reduced, and the noise generated by the turbulence is reduced accordingly. The fan blade is provided with a groove, when the air flow passes through the arc-shaped blade with a certain curvature in the rotating process of the fan blade, the flow speed of the air is continuously reduced, the corresponding pressure is continuously increased along the flow direction, the air micro-cluster is subjected to the friction force and the pressure difference force of the wall surface of the fan blade, and the two forces are opposite to the flowing direction. The air current is at the boundary layer along flabellum wall normal direction, under the effect of frictional force and pressure differential two power, the velocity of flow gradually tends to zero, frictional force also becomes zero correspondingly, but pressure differential power still exists, under this effect, gaseous micelle probably takes place the refluence of nearly wall, if take place to intersect with the gaseous micelle of flabellum wall following current, will flow to the direction of keeping away from the flabellum wall, make the intraformational air current lifting of boundary, produce the boundary layer separation and the vortex noise of air current, the recess that the trailing edge set up can be smashed into a little vortex group with the great vortex that produces along gaseous micelle flow direction, thereby reduce the exhibition of vortex group to the relevance and reduce the vortex noise. The groove is in reasonable transition along the curvature of the fan blade and is streamline, and the air flow vortex group is more stably transited in the noise reduction process due to the structure, so that excessive loss of air volume caused by large angles of other groove structures is avoided, and a certain noise reduction effect can be achieved. The notch of recess convergent has the effect of luring the air current, and the sectional area grow when the gas flow passes through here, and the dynamic pressure reduces, and the static pressure increases, and the gas velocity of flow reduces, further reduces aerodynamic noise. The inventor conducts fluid mechanics simulation analysis on the scheme, and the noise of the centrifugal fan is greatly improved.

Drawings

The centrifugal fan is described below with reference to the drawings. In the drawings:

FIG. 1 is a schematic structural diagram of a centrifugal fan according to the present invention;

FIG. 2 is a schematic structural view of a fan blade of the centrifugal fan of the present invention;

FIG. 3 is a schematic structural diagram of a groove of a fan blade of the centrifugal fan of the present invention;

FIG. 4 is a schematic view of the gas flow of the centrifugal fan of the present invention;

FIG. 5 is a cross-sectional view of an embodiment of a fan blade of a centrifugal fan according to the present invention.

List of reference numerals:

1-fan blade, 11-centripetal surface, 12-vest surface, 13-tail edge, 14-groove, 15-front edge, 16-first arc line, 17-second arc line, 18-inclined surface, 2-fan frame, 3-small vortex group and 4-large vortex.

Detailed Description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention. And can be adjusted as needed by those skilled in the art to suit particular applications. For example, although the fan frame 2 is described as a cylinder, it will be appreciated by those skilled in the art that the fan frame 2 may be an oval or a disc, etc., as long as the fan blades 1 can be fixed on the fan frame 2, without departing from the principle of the present invention, and thus, all of them will fall within the protection scope of the present invention.

It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are merely for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

As shown in fig. 1 to 4, in order to solve the problem of too much noise of the conventional centrifugal fan, the centrifugal fan of the present invention includes a fan blade 1, the fan blade 1 is in a curved plate shape, the fan blade 1 has a centripetal surface 11 and a vest surface 12, a groove 14 is provided at a trailing edge 13 of the fan blade 1, and the size of an opening of the groove 14 gradually shrinks toward a bottom end.

The setting mode has the advantages that: the centrifugal fan of the present invention has the curved plate-shaped fan blades 1, the change of the air flow direction is gradually changed, the curved plate-shaped fan blades 1 make the instantaneous impact action of the air flow on the fan blades 1 small, the air flow pressure loss is reduced, thereby the pressure difference of the air is reduced, the turbulence intensity is reduced, and the noise generated by the turbulence is correspondingly reduced. The fan blade 1 is provided with the groove 14, when the air flow passes through the arc-shaped blade with a certain curvature in the rotating process of the fan blade 1, the flow velocity of the air is continuously reduced, the corresponding pressure is continuously increased along the flow direction, and the air micro-cluster is subjected to the friction force and the pressure difference force of the wall surface of the fan blade, wherein the two forces are opposite to the flowing direction. The air current is at the boundary layer along flabellum 1 wall normal direction, under the effect of frictional force and pressure differential two power, the velocity of flow gradually tends to zero, frictional force also becomes zero correspondingly, but pressure differential still exists, under this effect, gaseous micelle can take place the refluence of nearly wall, if take place to intersect with the following current gaseous micelle of flabellum 1 wall, will flow to the direction of keeping away from flabellum 1 wall, make the air current lifting in the boundary layer, produce the boundary layer separation and the vortex noise of air current, the recess 14 that the trailing edge set up can be broken into a little vortex group 3 with the great vortex 4 that produces along gaseous micelle flow direction, thereby reduce the exhibition of vortex group to the relevance thereby reduce the vortex noise. The groove 14 is in reasonable transition along the curvature of the fan blade and is in a streamline shape, and the airflow vortex group is in more stable transition in terms of noise reduction, excessive loss of air volume due to large angles of other groove structures is avoided, and a certain noise reduction effect can be achieved. The opening of the groove 14 which is gradually reduced has the function of inducing airflow, the sectional area is enlarged when the air flows through the opening, the dynamic pressure is reduced, the static pressure is increased, the air flow speed is reduced, and the aerodynamic noise is further reduced. The inventor carries out fluid mechanics simulation analysis and actual experiment on the scheme, and the noise of the centrifugal fan is greatly improved.

As shown in fig. 2 and 3, in one possible embodiment, the centripetal surface 11 intersects with the inner surface of the groove 14 to form a first circular arc line 16, the vest surface 12 intersects with the inner surface of the groove 14 to form a second circular arc line 17, and the opening size of the first circular arc line 16 is larger than that of the second circular arc line 17.

The setting mode has the advantages that: the groove 14 arranged on the fan blade 1 has a tapered cutting structure from the centripetal surface 11 to the vest surface 12, and the opening size of the first circular arc line 16 is larger than that of the second circular arc line 17. The structure enables the fan blade 1 to form a larger opening on the centripetal side of the groove 14, in the rotating and air flowing process of the fan, on one hand, air flows from the surface of the front edge 15 of the fan blade 1 to the groove 14 of the tail edge 13, air flow is separated from a boundary layer to form air vortex, the air vortex is scattered into smaller vortex groups through the spline linear groove 14 to reduce aerodynamic noise, on the basis of the opening with the downward taper of the groove 14, the function of inducing the air flow is further enhanced through the taper cutting structure from the centripetal surface 11 to the vest surface 12, the air flow flows from the opening of the second arc line 17 to the opening of the first arc line 16, the sectional area is enlarged, the dynamic pressure is reduced, the static pressure is increased, the air flow speed is reduced, and the aerodynamic noise is further reduced.

As shown in fig. 1 and 2, in one possible embodiment, the trailing edge 13 of the fan blade 1 is an inclined surface 18, a plurality of grooves 14 are provided on the fan blade 1, the centrifugal fan includes a fan frame 2, the fan blades 1 are uniformly arranged on the fan frame 2, the fan frame 2 is cylindrical, and the leading edge 15 of the fan blade 1 is fixedly connected with the inner side wall of the fan frame 2.

The setting mode has the advantages that: the front edge 15 of flabellum 1 and fan frame 2 inside wall fixed connection, fan frame 2 fixes a plurality of flabellums 1 on it to rotate along with flabellum 1, the trailing edge 13 of flabellum 1 is inclined plane 18, and gas flows to trailing edge 13 department, and inclined plane 18 makes the air current accomplish the flow direction in the flabellum runner and turns to, thereby reduces the turbulent noise in the flabellum runner, makes the air flow to trailing edge 13 department, prevents that the air current from taking place the turbulent flow, causes efficiency loss to centrifugal fan.

In one possible embodiment, the fan blade 1 is integrally formed with the fan frame 2.

The setting mode has the advantages that: make flabellum 1 and fan frame 2 integrated into one piece setting through the mode of moulding plastics or machine tooling, improved the manufacturing installation accuracy of flabellum 1 greatly, avoided the seam gap after the concatenation or the windage influence that the seam arch brought, ensured that the air current gently turns to when getting into the segmental arc, improved centrifugal fan stability at the during operation. The noise is prevented from being generated by unstable reaction force generated by the airflow and the obstacle when the airflow meets the obstacle in the flowing process. Meanwhile, the fan blade 1 can run more stably, and the transition of the airflow vortex mass on the surface of the fan blade 1 is more stable, so that the noise of the fan blade 1 is reduced, and the running efficiency of the centrifugal fan is improved.

As shown in fig. 5, in a possible embodiment, the thickness of the fan blade 1 gradually decreases from the front edge 15 to the tail edge 13, and the fan blade 1 is provided with a cavity structure (not shown) outside the groove 14, and the cavity structure is provided with a reinforcing rib (not shown).

The setting mode has the advantages that: flabellum 1 is by the direction thickness taper of leading edge 15 to trailing edge 13, and flabellum 1 reduces along the direction thickness of radian to when lightening centrifugal fan weight, make the air current more smooth-going in the flow transition on flabellum 1's surface, the circulation of air is faster, and the windage is littleer, thereby reduces the production of noise, and has improved centrifugal fan's work efficiency. The cavity structure reduces the weight of the fan blade 1, and the reinforcing ribs reduce the weight of the fan blade 1 and improve the operation efficiency under the condition that the strength of the fan blade 1 is unchanged.

In summary, the centrifugal fan has the curved blade 1, the blade 1 is provided with the groove 14, when the airflow passes through the arc blade 1 with a certain curvature during the operation process, the flow velocity of the airflow is continuously reduced, the corresponding pressure is continuously increased along the flow direction, and the air micelle is subjected to the friction force and the pressure difference force of the wall surface of the blade 1, and the two forces are opposite to the flow direction. The flow velocity of the air flow in the boundary layer along the wall surface normal direction of the fan blade 1 gradually approaches zero under the action of two forces of friction force and differential pressure force, the friction force correspondingly becomes zero, but the differential pressure force still exists, and under the action of the force, the fluid in the boundary layer is lifted, and boundary layer separation and vortex noise are generated. The trailing edge 13 with the tapered groove can break up the larger vortex 4 generated in the flow direction of the gas micro-mass into one small vortex 3, reducing the spanwise dependence of the vortex and thus reducing the vortex noise. The groove 14 is in reasonable transition along the curvature of the fan blade 1 and is in a streamline shape, and for noise reduction, the transition of airflow vortex masses is more stable, excessive loss of air volume due to large angles of other triangular or polygonal groove structures is avoided, and a certain noise reduction effect can be achieved. On the basis, the gradually-reduced gap from the centripetal surface 11 to the vest surface 12 has the function of inducing airflow, the sectional area is gradually increased when the air flows through the gap, the dynamic pressure is reduced, the static pressure is increased, the air flow speed is reduced, and the aerodynamic noise is further reduced. The processing and mounting precision is better by integrally arranging the fan blades 1 and the fan frame 2, so that the rotation of the fan blades 1 is more stable, and the effect of the groove 14 structure is better. The trailing edge 13 is provided with an inclined surface 18 so that the flow of air at the inclined surface 18 reduces the occurrence of turbulence. The thickness of the fan blade 1 is gradually reduced from the front edge 15 to the tail edge 13, so that the transition of airflow vortex masses is more stable, and the occurrence of noise is reduced. The cavity structure arranged on the fan blade 1 reduces the weight of the fan blade 1 and improves the working efficiency of the centrifugal fan while not weakening the strength of the fan blade 1.

It should be noted that the above-mentioned embodiments are only used for illustrating the principle of the present invention, and are not intended to limit the protection scope of the present invention, and those skilled in the art can modify the above-mentioned structure so that the present invention can be applied to more specific application scenarios without departing from the principle of the present invention.

For example, in an alternative embodiment, the fan blade 1 is a curved plate, but the shape of the fan blade 1 is not limited, and may be an arc shape, a spiral shape, a regular shape such as a long strip or a semicircle, or other irregular shapes, as long as the groove 14 can be disposed thereon, without departing from the principle of the present invention, and therefore, the present invention is within the protection scope of the present invention.

For example, in another alternative embodiment, the front edge 15 of the fan blade 1 is fixedly connected to the inner sidewall of the fan frame 2, the front edge 15 of the fan blade 1 is fixedly connected to the outer sidewall of the fan frame 2, or the fan blades 1 are disposed on both inner and outer sidewalls of the fan frame 2, as long as the fan blades 1 can be fixed thereon and achieve the air flowing effect, which do not depart from the principle of the present invention and thus fall within the protection scope of the present invention.

For example, in another alternative embodiment, the trailing edge 13 of the fan blade 1 is provided with an inclined surface 18, or may be in other configurations such as a transitional arc, so long as the air flow can be diverted in the flow channel to prevent turbulent noise, without departing from the principle of the present invention, and therefore, the present invention is within the protection scope of the present invention.

For example, in another alternative embodiment, the number of fan blades 1 is not limited, and may be odd or even, and may be selected according to the specific model of the centrifugal fan, without departing from the principle of the present invention, and therefore, all fall within the protection scope of the present invention.

For example, in another alternative embodiment, the fan frame 2 is not limited to a ring structure, but may be a rotating shaft or a rotating disc, as long as it can function to fix the fan blades 1, without departing from the principle of the present invention, and therefore, it will fall within the protection scope of the present invention.

Finally, although the present invention is described by taking a centrifugal fan as an example, it is obvious that the fan blade 1 of the centrifugal fan of the present invention can also be applied to other fan apparatuses. For example, the axial flow fan can also be applied to a blower or the like.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

Claims

1. The centrifugal fan is characterized by comprising fan blades, wherein the fan blades are in a bent plate shape, the fan blades are provided with a centripetal surface and a vest surface, the tail edges of the fan blades are provided with grooves, and the size of the openings of the grooves is gradually shrunk to the size of the bottom ends.

2. The centrifugal fan according to claim 1, wherein the centripetal surface intersects the inner surface of the groove to form a first circular arc line, the vest surface intersects the inner surface of the groove to form a second circular arc line, and an opening dimension of the first circular arc line is larger than an opening dimension of the second circular arc line.

3. The centrifugal fan of claim 1 wherein the trailing edges of the fan blades are beveled.

4. The centrifugal fan as claimed in claim 3, wherein the recess is provided in plurality on the fan blade.

5. The centrifugal fan of claim 4, comprising a fan frame, wherein the fan blades are uniformly disposed on the fan frame.

6. The centrifugal fan of claim 5 wherein the fan frame is cylindrical or oval.

7. The centrifugal fan of claim 6 wherein the leading edges of the fan blades are fixedly attached to the inner sidewall of the fan frame.

8. The centrifugal fan of claim 6 wherein said fan blades are integrally formed with said fan frame.

9. The centrifugal fan of claim 1 wherein said fan blades taper in thickness from said leading edge to said trailing edge.

10. The centrifugal fan as claimed in claim 1, wherein the fan blades are provided with a cavity structure outside the groove, and the cavity structure is provided with a rib.