A low noise centrifugal fan

Abstract

The present invention proposes a low-noise centrifugal fan, which relates to the technical field of fans, and includes: a volute, wherein the volute has a mutually independent diffusion chamber and a volute chamber, the diffusion chamber is a circular cavity structure, the volute chamber is a spiral cavity structure, there is a connecting port between the diffusion chamber and the volute chamber, the connecting port is located at the beginning of the spiral cavity of the volute chamber, an air inlet is opened at the center of the side of the diffusion chamber facing the volute chamber, and the end of the spiral cavity of the volute chamber has an air outlet, and a fan impeller is rotatably arranged in the diffusion chamber, and the suction port of the fan impeller is connected to the air inlet; a driving motor is fixedly arranged on the side of the diffusion chamber away from the volute chamber, and is used to drive the fan impeller to rotate. The centrifugal fan disclosed in the present invention eliminates the volute tongue structure of the traditional centrifugal fan by setting a separate diffusion chamber and volute chamber, and adopts a cylindrical diffusion chamber and a spiral cavity volute chamber structure, and the connecting port between the diffusion chamber and the volute chamber is located at the beginning of the spiral cavity, so as to reduce airflow separation and vortex shedding, optimize airflow guidance, and reduce flow separation and throttling noise.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal fans, and in particular to a low-noise centrifugal fan. Background Art

[0002] Centrifugal fans are widely used in HVAC, energy and power, chemical processes, power cooling and other fields. They are the core equipment that provides power for air flow and overcomes pipe network resistance.

[0003] The noise generated by centrifugal fans during operation has become one of the main sources of environmental pollution in various fields such as household appliances and industrial production. It not only reduces people's work efficiency, but also has a great impact on people's physical and mental health. The noise pollution problem has attracted increasing attention. Therefore, it is very urgent and of practical significance to study the fan noise control method.

[0004] The causes of centrifugal fan noise can be divided into aerodynamic noise, noise generated by the interaction between gas and solid elastic system (i.e. coupling noise), mechanical structure noise and motor noise according to its nature and source. The first two are also called aerodynamic noise, and the last two are also called mechanical noise.

[0005] Aerodynamic noise is of high intensity and is the main noise in centrifugal fans. It is mainly caused by the following aspects: the interaction between the unstable flow of the airflow at the inlet of the centrifugal fan and the impeller, and the wide-band radiated by the coupling, including the incoming flow turbulence noise and the turbulent boundary layer noise; the airflow in the flow channel separates on the blade interface to produce vortices, and the vortex separation produces vortex shedding noise; the sudden diffusion of the airflow at the impeller flow channel outlet causes gas rarefaction and produces noise; the interaction between the high-speed airflow and the volute tongue produces blade tip vortex noise.

[0006] Traditional centrifugal fans place the fan impeller into the fan volute to achieve the gas expansion effect. Inevitably, due to the rotation of the fan impeller, the interaction between the airflow and the volute tongue will produce air noise. In addition, due to the small flow channel at the volute tongue, the high airflow velocity and high vortex intensity, there are violent flow separation and vortex shedding phenomena. Summary of the invention

[0007] In view of this, the present invention proposes a low-noise centrifugal fan to solve the problem of large aerodynamic noise in existing centrifugal fans.

[0008] The technical solution of the present invention is achieved in this way:

[0009] The present invention provides a low-noise centrifugal fan, comprising:

[0010] The volute has a mutually independent diffusion chamber and a volute chamber in the volute, the diffusion chamber is a circular cavity structure, the volute chamber is a spiral cavity structure, there is a communication port between the diffusion chamber and the volute chamber, the communication port is located at the beginning of the spiral cavity of the volute chamber, the diffusion chamber is provided with an air inlet at the center of one side facing the volute chamber, and the end of the spiral cavity of the volute chamber is provided with an air outlet,

[0011] A fan impeller is rotatably disposed in the expansion chamber, and a suction port of the fan impeller is connected to an air inlet;

[0012] The driving motor is fixedly arranged on a side of the diffusion chamber away from the volute chamber, and the output shaft of the driving motor is coaxially fixedly connected to the fan impeller.

[0013] On the basis of the above technical solution, preferably, the fan impeller includes a first disk body, a second disk body and arc-shaped blades, the first disk body and the second disk body are coaxially arranged in the diffusion chamber, a plurality of arc-shaped blades are fixedly arranged between the first disk body and the second disk body, and the plurality of arc-shaped blades are axially symmetrically distributed around the central axis of the diffusion chamber, and two adjacent arc-shaped blades form an air duct between the first disk body and the second disk body, and the suction port of the fan impeller is located at the center of the first disk body.

[0014] Further, preferably, the first disk body is in an arc-shaped convex shape, and the distance from the center of the first disk body to the second disk body is greater than the distance from the edge of the first disk body to the second disk body.

[0015] Furthermore, preferably, the diameter of the rotating body formed by one end of the plurality of arc-shaped blades facing the air inlet is less than or equal to the diameter of the air inlet.

[0016] On the basis of the above technical solution, preferably, the connecting port is located between the fan impeller and the inner wall of the diffuser chamber.

[0017] On the basis of the above technical solution, preferably, the cross-sectional area of ​​the volute chamber gradually increases from the beginning of the spiral cavity of the volute chamber to the end of the spiral cavity of the volute chamber.

[0018] Further, preferably, the cross section of the volute chamber is an arc-shaped structure.

[0019] On the basis of the above technical solution, preferably, it further includes an air inlet pipe fixedly connected to the air inlet, and the diameter of the air inlet pipe gradually increases from one end of the air inlet pipe close to the air inlet to the other end of the air inlet pipe away from the air inlet.

[0020] On the basis of the above technical solution, preferably, it also includes an air outlet pipe, which is fixedly connected to the air outlet, and the diameter of the air outlet pipe gradually increases from one end of the air outlet pipe close to the air outlet to the other end of the air outlet pipe away from the air outlet.

[0021] Further, preferably, the air outlet is located at the beginning of the spiral cavity of the volute chamber, and the air outlet pipe is connected with the diffusion chamber and the volute chamber in an intersecting manner.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The centrifugal fan proposed in the present invention has a separate diffuser chamber and a volute chamber structure inside the volute, which can realize the relative independence of the diffuser and guide functions of the fan, and create conditions for each link to independently carry out vibration and noise. The diffuser chamber adopts a cylindrical cavity structure, and the fan impeller is arranged in the diffuser chamber in an axisymmetric form. The fan impeller forms an axisymmetric flow field, and the airflow has no asymmetric pulsation phenomenon, and the flow separation and vortex shedding are less, the regeneration noise is low, and the structural fluid-solid coupling vibration is small. In addition, the volute chamber adopts a spiral cavity structure, which is connected in series with the diffuser chamber along the airflow direction. There is no fan impeller in the volute chamber, and there will be no fluid-solid coupling noise due to the periodic motion structure. In order to avoid turbulence in the airflow in the volute chamber, the connecting port between the diffuser chamber and the volute chamber is located at the beginning of the spiral cavity, and the size of the connecting port is determined according to the air volume of the fan, which can effectively reduce the flow separation and throttling noise.

[0024] (2) The fan impeller adopts an axisymmetric arc-shaped blade design, which allows the airflow to form a stable flow state in the fan impeller, reduces flow separation and vortex shedding, and thus reduces aerodynamic noise. The arc-shaped blades can guide the airflow more effectively, reduce the separation and backflow of the airflow in the process of passing through the impeller, and improve the stability of the airflow and the efficiency of the fan. Two adjacent arc-shaped blades form an air duct between the first disk and the second disk, so that the airflow can enter the diffuser chamber through the impeller air duct in an orderly and stable manner, thereby improving the speed and transmission efficiency of the airflow.

[0025] (3) By configuring the first disk body to be an arc-shaped protrusion, the flow characteristics of the airflow through the impeller can be improved, the separation of the airflow on the impeller surface and the generation of vortices can be reduced, and the dynamic pressure balance of the airflow from the center to the edge can be ensured.

[0026] (4) By arranging the connecting port between the fan impeller and the inner wall of the diffuser chamber, the airflow can be better guided from the diffuser chamber into the volute chamber, reducing airflow resistance and energy loss. In addition, this position setting ensures that the airflow can be evenly distributed in the diffuser chamber before entering the volute chamber, avoiding interference and separation of the airflow before entering the volute chamber, and reducing the noise generated by vortex.

[0027] (5) The cross-sectional area of ​​the volute chamber is gradually increased from the beginning of the spiral cavity of the volute chamber to the end of the spiral cavity of the volute chamber. The speed of the airflow in the volute chamber is gradually reduced, and the pressure is gradually increased, so that the kinetic energy is more effectively converted into static pressure energy, which improves the overall efficiency of the fan and enhances the working performance of the fan. The gradual increase in the cross-sectional area makes the speed of the airflow gradually decrease, reducing the friction and impact between the high-speed airflow and the wall of the volute chamber, thereby reducing the aerodynamic noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a three-dimensional structural schematic diagram of the low-noise centrifugal fan disclosed in the present invention;

[0030] Figure 2 A top view of the low-noise centrifugal fan disclosed in the present invention;

[0031] Figure 3 for Figure 2 Plane section view at AA in the middle;

[0032] Figure 4 It is a schematic diagram of the internal structure of the low-noise centrifugal fan disclosed in the present invention;

[0033] Figure 5 It is a schematic diagram of the three-dimensional structure of the volute disclosed in the present invention;

[0034] Figure 6 It is a schematic diagram of the internal structure of the volute disclosed in the present invention;

[0035] Figure 7 It is a schematic diagram of the three-dimensional structure of the fan impeller disclosed in the present invention;

[0036] Figure 8 It is a front view of the low-noise centrifugal fan disclosed in the present invention;

[0037] Fig. 9 for Figure 8 Plane section view at BB in the middle;

[0038] Reference numerals:

[0039] 1. Volute; 11. Diffuser chamber; 12. Volute chamber; 10. Connecting port; 111. Air inlet; 121. Air outlet; 2. Fan impeller; 3. Driving motor; 21. First disk; 22. Second disk; 23. Curved blades; 20. Air duct; 24. Inlet; 4. Air inlet duct; 5. Air outlet duct. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figure 1 As shown, combined Figure 2-6 The present invention discloses a low-noise centrifugal fan, comprising a volute 1, a fan impeller 2 and a drive motor 3.

[0042] Among them, the volute 1 has independent diffusion chambers 11 and volute chambers 12, and an air inlet 111 is opened at the center of one side of the diffusion chamber 11 facing the volute chamber 12. The fan impeller 2 is rotatably arranged in the diffusion chamber 11, and the suction port 24 of the fan impeller 2 is connected to the air inlet 111.

[0043] In this embodiment, the air inlet 111 serves as a channel connecting the inside and outside of the centrifugal fan, which introduces external airflow and sends it to the suction port 24 of the fan impeller 2. The fan impeller 2 transfers mechanical energy to the gas through rotation, and can also convert part of the kinetic energy of the gas into static pressure energy, thereby increasing the pressure of the gas.

[0044] The driving motor 3 is fixedly arranged on a side of the diffusion chamber 11 away from the volute chamber 12, and the output shaft of the driving motor 3 is coaxially fixedly connected with the fan impeller 2. The driving motor 3 transmits mechanical energy to the fan impeller 2, so that the fan impeller 2 continuously inhales the external airflow and performs centrifugal motion, and sends the airflow from the outlet of the impeller into the diffusion chamber 11.

[0045] In this embodiment, the diffusion chamber 11 is a circular cavity structure, and the volute chamber 12 is a spiral cavity structure. There is a connecting port 10 between the diffusion chamber 11 and the volute chamber 12. The connecting port 10 is located at the starting point of the spiral cavity of the volute chamber 12, and the end of the spiral cavity of the volute chamber 12 has an air outlet 121.

[0046] With this arrangement, a high-speed airflow flows from the impeller outlet into the diffusion chamber 11, and the kinetic energy generated by the fan impeller 2 after doing work on the gas is converted into static pressure energy. In this embodiment, the fan impeller 2 is arranged in the diffusion chamber 11, and the diffusion chamber 11 and the volute chamber 12 are connected in series along the airflow direction. The connecting port 10 between the diffusion chamber 11 and the volute chamber 12 is located at the beginning of the spiral cavity of the volute chamber 12. The caliber of the connecting port 10 can be determined according to the air volume of the centrifugal fan. The larger the air volume, the larger the caliber design of the connecting port 10. By setting the connecting port 10, the air flow rate between the two chambers can be reduced, thereby reducing the air noise caused by throttling. The volute chamber 12 can further expand the gas flowing into the diffusion chamber 11, and along the spiral cavity, the kinetic energy of the gas is converted into static pressure energy, and the pressurized air is drawn out from the air outlet 121.

[0047] Traditional centrifugal fans generally use an integrated volute 1, and functions such as pressure diffusion and airflow guidance are all completed in the volute 1. However, the separate pressure diffusion chamber 11 and volute chamber 12 structure proposed in the present invention can achieve relative independence of the fan's pressure diffusion and guidance functions, creating conditions for each link to independently carry out vibration and noise.

[0048] The diffuser chamber 11 of a traditional centrifugal fan adopts an asymmetric structure, and the airflow is prone to pulsation in the diffuser chamber 11, thereby exciting air noise and fluid-solid coupling vibration. The diffuser chamber 11 proposed in the present invention adopts a cylindrical cavity structure, and the fan impeller 2 is arranged in the diffuser chamber 11 in an axisymmetric form. The fan impeller 2 forms an axisymmetric flow field, and the airflow has no asymmetric pulsation phenomenon, and there is less flow separation and vortex shedding, low regeneration noise, and small structural fluid-solid coupling vibration. In addition, the volute chamber 12 adopts a spiral cavity structure, which is connected in series with the diffuser chamber 11 along the flow direction of the airflow. There is no fan impeller 2 in the volute chamber 12, and there will be no fluid-solid coupling noise due to the periodic motion structure. In order to avoid turbulence in the airflow in the volute chamber 12, the connecting port 10 between the diffuser chamber 11 and the volute chamber 12 is located at the beginning of the spiral cavity, and the size of the connecting port 10 is determined according to the air volume of the fan, which can effectively reduce flow separation and throttling noise.

[0049] As some preferred implementations, refer to the attached Figure 3 , 4 , 7, 8 and appendix Fig. 9 As shown, the fan impeller 2 includes a first disk body 21, a second disk body 22 and arc-shaped blades 23. The first disk body 21 and the second disk body 22 are coaxially arranged in the diffusion chamber 11 at intervals. A plurality of arc-shaped blades 23 are fixedly arranged between the first disk body 21 and the second disk body 22. The plurality of arc-shaped blades 23 are axially symmetrically distributed around the central axis of the diffusion chamber 11. Two adjacent arc-shaped blades 23 form an air duct 20 between the first disk body 21 and the second disk body 22. The suction port 24 of the fan impeller 2 is located at the center of the first disk body 21.

[0050] With the above technical solution, the fan impeller 2 is designed with an axisymmetric arc blade 23, so that the airflow forms a stable flow state in the fan impeller 2, reducing flow separation and vortex shedding, thereby reducing aerodynamic noise. The arc blade 23 can guide the airflow more effectively, reduce the separation and backflow of the airflow in the process of passing through the impeller, and improve the stability of the airflow and the efficiency of the fan. Two adjacent arc blades 23 form an air duct 20 between the first disk 21 and the second disk 22, so that the airflow can enter the diffuser chamber 11 through the air duct 20 in an orderly and stable manner, thereby improving the speed and transportation efficiency of the airflow.

[0051] As some preferred embodiments, the first disk 21 is in an arc-shaped convex shape, and the distance from the center of the first disk 21 to the second disk 22 is greater than the distance from the edge of the first disk 21 to the second disk 22. The arc-shaped convex shape of the first disk 21 can improve the flow characteristics of the airflow through the impeller, reduce the separation of the airflow on the impeller surface and the generation of vortices, and ensure the balance of the airflow dynamic pressure from the center to the edge.

[0052] Preferably, the diameter of the rotating body formed by one end of the plurality of arc-shaped blades 23 facing the air inlet 111 is less than or equal to the diameter of the air inlet 111. The above technical solution effectively reduces the air flow resistance between the air inlet 111 and the blades, so that the air flow can enter the impeller more smoothly, reducing energy loss and noise generation.

[0053] In this embodiment, the communication port 10 is located between the fan impeller 2 and the inner wall of the diffuser chamber 11. This arrangement can better guide the airflow from the diffuser chamber 11 into the volute chamber 12, reducing airflow resistance and energy loss. In addition, this position setting ensures that the airflow can be evenly distributed in the diffuser chamber 11 before entering the volute chamber 12, avoiding interference and separation of the airflow before entering the volute chamber 12, and reducing the noise generated by the vortex.

[0054] In this embodiment, the cross-sectional area of ​​the volute chamber 12 gradually increases from the beginning of the spiral cavity of the volute chamber 12 to the end of the spiral cavity of the volute chamber 12. With this structural setting, the speed of the airflow in the volute chamber 12 gradually decreases, and the pressure gradually increases, so that the kinetic energy is more effectively converted into static pressure energy, the overall efficiency of the fan is improved, and the working performance of the fan is enhanced. The gradual increase in the cross-sectional area gradually reduces the speed of the airflow, reduces the friction and impact between the high-speed airflow and the wall of the volute chamber 12, and thus reduces the aerodynamic noise.

[0055] In this embodiment, the cross section of the volute chamber 12 is an arc-shaped structure. With this arrangement, the airflow can flow more smoothly along the wall of the volute chamber 12, reducing the friction and impact between the airflow and the wall of the volute chamber 12, and reducing the airflow noise. The smooth transition of the arc helps to reduce eddy currents and turbulence, further reducing noise.

[0056] As some preferred embodiments, the centrifugal fan disclosed in the present invention further includes an air inlet pipe 4 fixedly connected to the air inlet 111, and the diameter of the air inlet pipe 4 gradually increases from the end of the air inlet pipe 4 close to the air inlet 111 to the end of the air inlet pipe 4 away from the air inlet 111. With the above-mentioned structural arrangement, the air inlet pipe 4 is a bell-mouth structure, which can effectively guide the airflow into the fan, reduce the resistance when the airflow enters, and improve the air intake efficiency of the fan.

[0057] As some preferred embodiments, the centrifugal fan disclosed in the present invention further includes an air outlet pipe 5, which is fixedly connected to the air outlet 121, and the diameter of the air outlet pipe 5 gradually increases from the end of the air outlet pipe 5 close to the air outlet 121 to the end of the air outlet pipe 5 away from the air outlet 121. In this embodiment, the air outlet pipe 5 is connected to the end of the spiral cavity of the volute chamber 12, further converting the low-pressure airflow generated by the fan into a high-pressure airflow to meet the needs of the system and serving as a fan outlet.

[0058] In this embodiment, the air outlet 121 is located at the beginning of the spiral cavity of the volute chamber 12, and the air outlet pipe 5 is connected to the expansion chamber 11 and the volute chamber 12 in an intersecting form. With this arrangement, the entire centrifugal fan has a compact structure, smooth airflow, and low fluid-solid coupling noise; because of the expansion effect of the vortex chamber, the airflow velocity gradually decreases, and the static pressure gradually increases. At the air outlet pipe 5, the airflow dynamic pressure has been mostly converted into static pressure, and the vortex intensity at the air outlet pipe 5 is greatly weakened. Compared with the vortex intensity at the volute tongue of the traditional fan, the regeneration noise will be greatly reduced.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low noise centrifugal fan, characterized in that: include: A volute (1), wherein the volute (1) has a mutually independent diffusion chamber (11) and a volute chamber (12), wherein the diffusion chamber (11) is a circular cavity structure, and the volute chamber (12) is a spiral cavity structure, wherein a communication port (10) is provided between the diffusion chamber (11) and the volute chamber (12), wherein the communication port (10) is located at the beginning of the spiral cavity of the volute chamber (12), wherein an air inlet (111) is provided at the center of one side of the diffusion chamber (11) facing the volute chamber (12), and an air outlet (121) is provided at the end of the spiral cavity of the volute chamber (12), A fan impeller (2) is rotatably disposed in the diffusion chamber (11), and a suction port (24) of the fan impeller (2) is connected to an air inlet (111); A drive motor (3) is fixedly arranged on a side of the diffusion chamber (11) away from the volute chamber (12), and an output shaft of the drive motor (3) is coaxially fixedly connected to the fan impeller (2); The communication port (10) is located between the fan impeller (2) and the inner wall of the diffusion chamber (11); The cross-sectional area of ​​the volute chamber (12) gradually increases from the starting point of the spiral cavity of the volute chamber (12) to the end point of the spiral cavity of the volute chamber (12), and the cross-sectional area of ​​the volute chamber (12) is an arc-shaped structure.

2. The low noise centrifugal fan according to claim 1, characterized in that: The fan impeller (2) comprises a first disk body (21), a second disk body (22) and arc-shaped blades (23); the first disk body (21) and the second disk body (22) are coaxially arranged in a diffusion chamber (11) at intervals; a plurality of arc-shaped blades (23) are fixedly arranged between the first disk body (21) and the second disk body (22); the plurality of arc-shaped blades (23) are axially symmetrically distributed around the central axis of the diffusion chamber (11); two adjacent arc-shaped blades (23) form an air duct (20) between the first disk body (21) and the second disk body (22); and the suction port (24) of the fan impeller (2) is located at the center of the first disk body (21).

3. The low noise centrifugal fan according to claim 2, characterized in that: The first disk body (21) is in an arc-shaped convex shape, and the distance from the center of the first disk body (21) to the second disk body (22) is greater than the distance from the edge of the first disk body (21) to the second disk body (22).

4. The low noise centrifugal fan according to claim 3, characterized in that: The diameter of the rotating body formed by one end of the plurality of arc-shaped blades (23) facing the air inlet (111) is less than or equal to the diameter of the air inlet (111).

5. The low noise centrifugal fan according to claim 1, characterized in that: It also comprises an air inlet pipe (4) fixedly connected to the air inlet (111), wherein the diameter of the air inlet pipe (4) gradually increases from an end of the air inlet pipe (4) close to the air inlet (111) to an end of the air inlet pipe (4) away from the air inlet (111).

6. The low noise centrifugal fan according to claim 1, characterized in that: It also comprises an air outlet pipe (5), wherein the air outlet pipe (5) is fixedly connected to the air outlet (121), and the diameter of the air outlet pipe (5) gradually increases from an end of the air outlet pipe (5) close to the air outlet (121) to an end of the air outlet pipe (5) far from the air outlet (121).

7. The low noise centrifugal fan according to claim 6, characterized in that: The air outlet (121) is located at the beginning of the spiral cavity of the volute chamber (12), and the air outlet pipe (5) is connected to the diffusion chamber (11) and the volute chamber (12) in an intersecting manner.

Images