Multi-wing centrifugal fan

Abstract

The invention relates to the technical field of centrifugal fans, in particular to a multi-wing centrifugal fan which comprises a volute and an impeller. The volute is provided with an air outlet and two air inlets; the impeller comprises a hub disc, a hub, two reinforcing rings and two sets of blade assemblies, the hub is fixedly connected to the center of the hub disc, the two sets of blade assemblies are arranged on the two opposite side faces of the hub disc in a staggered mode, and each set of blade assembly is fixedly connected with the inner ring of one reinforcing ring; each blade assembly comprises a plurality of blades, and the blades of the two blade assemblies are the same in structure. The impeller is installed in the volute according to the preset size proportion and structure parameters. The structural design of the impeller and the volute is optimized, key size parameters are accurately matched, the positioning relation of all parts is defined, the aerodynamic performance, operation stability and assembly consistency of the fan are improved, and operation noise and abrasion are reduced.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan technology, and more particularly to a multi-blade centrifugal fan. Background Technology

[0002] Multi-blade centrifugal fans are widely used in air conditioning, ventilation, refrigeration and other fields due to their large flow rate, moderate pressure and low noise. Existing multi-blade centrifugal fans usually adopt a single-inlet or dual-inlet structure. Among them, the dual-inlet structure has become the preferred choice for medium and large air volume requirements because it can effectively improve air intake efficiency and balance the force on the impeller.

[0003] However, the dual-inlet multi-blade centrifugal fans currently on the market still have many shortcomings: First, the connection between the impeller blades and the reinforcing ring is abrupt, and the blade tips are mostly flush, which easily generates airflow vortices, leading to decreased fan efficiency and increased noise; Second, the assembly and positioning accuracy of the impeller and volute is insufficient, making it difficult to guarantee the overlap of the rotating shaft, which can easily lead to vibration and wear problems during long-term operation; Third, the size ratio and structural parameters of the impeller and volute are not designed reasonably, especially the low matching degree of key parameters such as blade angle, volute profile, and clearance size, which further restricts the aerodynamic performance and operational stability of the fan; Fourth, the definitions of some key parameters are vague and the references are chaotic, making it difficult to control the production and assembly accuracy of the fan, resulting in poor product consistency during mass production.

[0004] To address the aforementioned issues, there is an urgent need for a multi-bladed centrifugal fan with a reasonable structural design, precise parameter matching, and stable and efficient operation to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] The purpose of this invention is to propose a multi-blade centrifugal fan to solve the technical problems of low efficiency, high noise, unstable operation, and poor production consistency in existing multi-blade centrifugal fans.

[0006] To achieve this objective, the present invention adopts the following technical solution: A multi-blade centrifugal fan includes a volute and an impeller; The volute has an air outlet and two air inlets. The planes containing the two air inlets are arranged relatively parallel to each other. The center of the two air inlets is defined as axis O', and the axis passing through the two axis O' is defined as the rotation axis of the volute. The impeller includes a hub disk, a hub, two reinforcing rings, and two sets of blade assemblies. The hub is fixedly connected to the center of the hub disk, and the two sets of blade assemblies are arranged alternately on two opposite sides of the hub disk. Each set of blade assemblies is fixedly connected to the inner ring of one of the reinforcing rings. The blade assembly includes a plurality of blades, and each blade in the two sets of blade assemblies has the same structure. The peripheral contour of the blade is formed by the blade leading edge, blade top edge, blade trailing edge and blade bottom edge. The plurality of blades are evenly distributed at equal intervals on the corresponding side of the hub disk, and the bottom edge of each blade is fixedly connected to the corresponding side of the hub disk. The trailing edge of each blade is flush with the outer edge of the hub disk. The trailing edge of each blade is also fixedly connected to the inner ring of the corresponding reinforcing ring. The top edge of each blade is smoothly connected to the top edge of the corresponding reinforcing ring, and the top edge of each blade and the top edge of the corresponding reinforcing ring form a non-flush blade top structure. The center of the hub disk and the center of the two reinforcing rings overlap and are defined as the axis O of the impeller. The axis passing through the axis O and perpendicular to the surface of the hub disk is defined as the rotation axis of the impeller. The impeller is installed inside the volute according to a preset size ratio and structural parameters, and the shaft center O and shaft center O' are overlapped. The rotation axis of the impeller is collinear with the rotation axis of the volute.

[0007] Preferably, both sets of blade assemblies each contain Z blades, and the stagger angle between the two sets of blade assemblies on the two sides of the hub disk is 360° / Z / 2, where 39 ≤ Z ≤ 47.

[0008] Preferably, the axial distance between the highest and lowest points of a single non-flush blade tip structure is defined as B4 by projecting along a direction perpendicular to the rotation axis of the volute. Define the axial distance between the highest points of the non-flush blade tip structures of the two sets of blade assemblies as B1; The axial distance between the highest point of the non-flush blade tip structure of the two sets of blade assemblies and the inner wall of the volute is defined as B2. The axial distance between the lowest point of the non-flush blade tip structure of the two sets of blade assemblies and the end of the air guide is defined as B3. The cross-sectional shape of the air guide is an arc, and the radius of the arc of the air guide is defined as r1; Wherein, 125mm≤B1≤155mm, 2mm≤B2-r1≤5mm, 4mm≤B3≤8mm, and B4=B3-(B2-r1).

[0009] Preferably, by projecting along the direction of the impeller rotation axis, the leading edges of all blades in the same group of blade assemblies are connected with the axis O as the center to form the inner circle of the blade, and the diameter of the inner circle of the blade is defined as the impeller inner diameter D2. The inner diameter of the reinforcing ring is defined as the impeller outer diameter D1; Define the outer diameter of the reinforcement ring as the impeller diameter D3; where, D1 / D2 = 1.15 to 1.25, D3 = D1 + 2.8 mm.

[0010] Preferably, the edges of the two air inlets of the volute extend towards the interior of the volute and gradually indent inward to form air guiding parts, and the ends of the air guiding parts enclose to form an air guiding opening. The shapes of the air inlet and the air guiding opening are both circular. Define the diameter of the air guiding opening as D4; where, D4 / D2 = 1.03 to 1.05.

[0011] Preferably, when projected along the direction of the impeller rotation axis, each blade in the blade assembly has an inlet angle β1 and an outlet angle β2; where, β1 = 78° to 83°, β2 = 155° to 160°.

[0012] Preferably, when projected along the direction of the volute rotation axis, the inner wall of the volute forms a volute profile, and the volute profile is enclosed by an outlet section, a diffuser section, and a volute tongue section; The diffuser section includes a first arc segment, a second arc segment, a third arc segment, and a fourth arc segment connected in sequence. Define the starting end point of the first arc segment as design point P1, the connection point of the first arc segment and the second arc segment as design point P2, the connection point of the second arc segment and the third arc segment as design point P3, the connection point of the third arc segment and the fourth arc segment as design point P4, and the terminating end point of the fourth arc segment as design point P5; The first arc segment is controlled and set by design points P1 and P2, and the circular radius corresponding to the first arc segment is R1; The second arc segment is controlled and set by design points P2 and P3, and the circular radius corresponding to the second arc segment is R2; The third arc segment is controlled and set by design points P3 and P4, and the circular radius corresponding to the third arc segment is R3; The fourth arc segment is controlled and set by design points P4 and P5, and the circular radius corresponding to the fourth arc segment is R4; where, R2 < R1 < R3 < R4, and the difference amplitude between any two adjacent circular radii does not exceed 10%.

[0013] Preferably, define the linear distance between design point P3 and design point P5 as the volute width Dh; Define the shortest linear distance from design point P3 to the outer circle of the reinforcement ring as A1; Define the shortest linear distance from design point P5 to the outer circle of the reinforcement ring as A; Among them, 1.3≤Dh / D3≤1.4, 4.5≤A / A1≤5.5.

[0014] Preferably, the cochlear tongue segment includes a fifth arc segment; The two endpoints of the fifth arc segment are defined as design point P0 and design point P1, respectively. The radius of the circle corresponding to the fifth arc segment is the radius r of the volute tongue. The shortest straight-line distance between the fifth arc segment and the outer ring of the reinforcing ring is defined as the volute tongue gap t; Where r < R2, 0.04 ≤ t / D3 ≤ 0.05.

[0015] Preferably, the blade has a pressure surface and a suction surface, which are arranged opposite to each other; Projected along the direction of the impeller's rotation axis, the pressure surface and the suction surface respectively form a pressure flange profile and a suction flange profile; The pressure flange profile is the sixth arc segment, and the two endpoints of the sixth arc segment are defined as design point Q0 and design point Q1, respectively. The radius of the circle corresponding to the sixth arc segment is R5. The suction edge profile includes a seventh arc segment, an eighth arc segment, and a ninth arc segment connected sequentially. The seventh arc segment is located near the trailing edge of the blade, and the ninth arc segment is located near the leading edge of the blade. The starting endpoint of the seventh arc segment is defined as design point Q2, the connection point between the seventh and eighth arc segments is defined as design point Q3, the connection point between the eighth and ninth arc segments is defined as design point Q4, and the ending endpoint of the ninth arc segment is defined as design point Q5. The seventh arc segment is controlled by design points Q2 and Q3, and the radius of the circle corresponding to the seventh arc segment is R6. The eighth arc segment is controlled by design points Q3 and Q4, and the radius of the circle corresponding to the eighth arc segment is R7. The ninth arc segment is controlled by design points Q4 and Q5, and the radius of the circle corresponding to the ninth arc segment is R8. Among them, R8 < R5 < R7 < R6.

[0016] One of the above technical solutions has the following beneficial effects: In summary, the multi-blade centrifugal fan of the present invention has the following advantages compared with the prior art: 1. Reasonable structural design: The dual-inlet symmetrical structure, combined with staggered double-blade assemblies, allows airflow to enter the impeller evenly, balances the impeller force, and reduces vibration; the blade tip edge and the reinforcing ring tip edge smoothly transition to form a non-flush blade tip structure, which effectively reduces eddy current loss and lowers operating noise.

[0017] 2. Precise and reliable positioning: The impeller and volute shafts and the rotating shaft are all set to coincide, ensuring that the impeller rotates in the center, avoiding friction and collision, and improving operational stability and service life; the hub disc and the reinforcing ring are aligned to ensure the dynamic balance performance of the impeller and reduce vibration during high-speed rotation.

[0018] 3. Precise parameter matching: Clearly define the definition and proportion range of each key dimension parameter, optimize core parameters such as blade angle, volute profile, and clearance size, so that the impeller and volute are perfectly matched, improving the aerodynamic efficiency and operational stability of the fan, while facilitating mass production and ensuring product consistency.

[0019] 4. High structural strength: The blades adopt a double fixing method, combined with the reinforcement ring, to effectively prevent deformation and breakage of the blades when rotating at high speed; the connection of each component is reliable, the overall structure is stable, and it is suitable for long-term high-speed operation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a multi-blade centrifugal fan. Figure 2 This is a schematic diagram of the impeller structure in a multi-blade centrifugal fan. Figure 3 yes Figure 2 A magnified view of a portion of point a; Figure 4 This is a side view schematic diagram of the impeller in a multi-blade centrifugal fan; Figure 5 This is a schematic diagram of the design of a multi-blade centrifugal fan projected along the axis of rotation. Figure 6 This is a schematic diagram of the design of a multi-blade centrifugal fan projected along a cross section perpendicular to the axis of rotation; Figure 7 This is a design schematic diagram of an impeller in a multi-blade centrifugal fan; Figure 8 This is a schematic diagram of the cross-section of a blade in a multi-blade centrifugal fan; Figure 9 This is a schematic diagram of the blade design in a multi-blade centrifugal fan. In the attached diagram: volute 1, air outlet 11, air inlet 12, air guide 13, air guide 14, impeller 2, hub disc 21, hub 22, reinforcing ring 23, blade assembly 24, blade 241, blade leading edge 2411, blade tip edge 2412, blade trailing edge 2413, blade bottom edge 2414, pressure surface 2415, suction surface 2416, non-flush blade tip structure 25. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "left," "right," "vertical," "level," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] A multi-blade centrifugal fan includes a volute 1 and an impeller 2; The volute 1 has an air outlet 11 and two air inlets 12. The planes on which the two air inlets 12 are located are arranged relatively parallel. The center of the two air inlets 12 is defined as the axis O', and the axis passing through the two axis O' is defined as the rotation axis of the volute 1. The impeller 2 includes a hub disk 21, a hub 22, two reinforcing rings 23 and two sets of blade assemblies 24. The hub 22 is fixedly connected to the center of the hub disk 21. The two sets of blade assemblies 24 are respectively arranged alternately on two opposite sides of the hub disk 21, and each set of blade assemblies 24 is fixedly connected to the inner ring of one of the reinforcing rings 23. The blade assembly 24 includes a plurality of blades 241, and each blade 241 in both sets of blade assemblies 24 has the same structure. The peripheral contour of the blade 241 is formed by the leading edge 2411, the top edge 2412, the trailing edge 2413, and the bottom edge 2414. The plurality of blades 241 are evenly distributed at equal intervals on the corresponding side of the hub disk 21, and the bottom edge 2414 of each blade 241 is aligned with the corresponding side of the hub disk 21. The blades are fixedly connected, and the trailing edge 2413 of each blade 241 is flush with the outer edge of the hub disk 21. The trailing edge 2413 of each blade 241 is also fixedly connected to the inner ring of the corresponding reinforcing ring 23. The top edge 2412 of each blade 241 is smoothly connected to the top edge of the corresponding reinforcing ring 23, and the top edge 2412 of each blade 241 and the top edge of the corresponding reinforcing ring 23 form a non-flush blade tip structure 25. The center of the hub disk 21 and the center of the two reinforcing rings 23 are overlapped and defined as the axis O of the impeller 2. The axis passing through the axis O and perpendicular to the disk surface of the hub disk 21 is defined as the rotation axis of the impeller 2. The impeller 2 is installed inside the volute 1 according to a preset size ratio and structural parameters, and the shaft center O and shaft center O' are overlapped. The rotation axis of the impeller 2 is collinear with the rotation axis of the volute 1.

[0026] like Figure 1-8 As shown, this technical solution precisely matches the volute 1 and impeller 2 with preset size ratios and structural parameters to ensure stable and efficient operation of the fan.

[0027] The volute 1 serves as the airflow guide and containment component of the fan, and has an air outlet 11 and two air inlets 12. The two air inlets 12 are symmetrically arranged, and their planes are relatively parallel. The center of the two air inlets 12 is defined as the axis O', and the axis passing through the axis O' is the rotation axis of the volute 1. This design allows the airflow to enter the interior of the volute 1 evenly from the two air inlets 12, avoiding problems such as airflow deflection and eddies caused by unilateral airflow.

[0028] The impeller 2 is the core working component of the wind turbine, including a hub disc 21, a hub 22, two reinforcing rings 23, and two sets of blade assemblies 24. The hub 22 is fixedly connected to the center of the hub disc 21 and is used to connect to a drive device such as the output shaft of a motor to transmit driving force. The two sets of blade assemblies 24 are staggered on two opposite sides of the hub disc 21, and each set of blade assemblies 24 is fixedly connected to the inner ring of a reinforcing ring 23. The reinforcing rings 23 enhance the structural strength of the blade assemblies 24, preventing the blades 241 from deforming or breaking during high-speed rotation, thus extending the service life of the impeller 2.

[0029] The blade assembly 24 includes several blades 241. Each blade 241 in the two sets of blade assemblies 24 has the same structure, which facilitates mass production and assembly. The peripheral contour of the blade 241 is formed by the leading edge 2411, the top edge 2412, the trailing edge 2413, and the bottom edge 2414. Several blades 241 are evenly distributed at equal intervals on the corresponding sides of the hub disk 21 to ensure uniform airflow force. The bottom edge 2414 of each blade 241 is fixedly connected to the corresponding side of the hub disk 21, and the trailing edge 2413 of the blade is flush with the outer edge of the hub disk 21. At the same time, the trailing edge 2413 of the blade is also fixedly connected to the inner ring of the corresponding reinforcing ring 23, realizing the double fixation of the blade 241 and improving the structural stability. The top edge 2412 of each blade 241 is smoothly connected to the top edge of the corresponding reinforcing ring 23, and the two form a non-flush blade tip structure 25. This structure can effectively reduce the vortex loss of airflow at the blade tip, reduce operating noise, and improve the aerodynamic efficiency of the fan.

[0030] To ensure the dynamic balance performance of the impeller 2 during rotation, the center of the hub disk 21 is set to coincide with the center of the two reinforcing rings 23. This coincident center point is defined as the shaft center O of the impeller 2, and the axis passing through the shaft center O and perpendicular to the disk surface of the hub disk 21 is defined as the rotation axis of the impeller 2.

[0031] The impeller 2 is assembled inside the volute 1, and the axis O of the impeller 2 coincides with the axis O' of the volute 1. The rotation axis of the impeller 2 is collinear with the rotation axis of the volute 1, ensuring that the impeller 2 rotates centrally inside the volute 1, avoiding friction and collision between the impeller 2 and the inner wall of the volute 1, while ensuring that the airflow trajectory inside the volute 1 is reasonable and improving the efficiency of the fan.

[0032] To further explain, both sets of blade assemblies 24 each include Z blades 241, and the stagger angle of the two sets of blade assemblies 24 on the two sides of the hub disk 21 is 360° / Z / 2, where 39 ≤ Z ≤ 47.

[0033] like Figure 2 and Figure 4 As shown, the above-mentioned staggered angle design can effectively cancel the aerodynamic noise generated when the two sets of blade assemblies 24 rotate, reduce noise superposition, further reduce the overall operating noise of the fan, and at the same time ensure the dynamic balance performance of the impeller 2 and improve the operational stability. In a preferred embodiment, Z=41, then the staggered angle is 360° / 41 / 2≈4.39°.

[0034] To further explain, projecting along a direction perpendicular to the rotation axis of the volute 1, the axial distance between the highest and lowest points of a single non-flush blade tip structure 25 is defined as B4. Define the axial distance between the highest points of the non-flush blade tip structure 25 of the two sets of blade assemblies 24 as B1; The axial distance between the highest point of the non-flush blade tip structure 25 of the two sets of blade assemblies 24 and the inner wall of the volute 1 is defined as B2. The axial distance between the lowest point of the non-flush blade tip structure 25 of the two sets of blade assemblies 24 and the end of the air guide 13 is defined as B3. The cross-sectional shape of the air guide 13 is an arc, and the radius of the arc of the air guide 13 is defined as r1; Among them, 125mm≤B1≤155mm, 2mm≤B2-r1≤5mm, 4mm≤B3≤8mm, and B4=B3-(B2-r1).

[0035] like Figure 3 and Figure 6 As shown, the precise matching of the above-mentioned dimensional parameters ensures a reasonable gap between the blade tip and the inner wall of the volute 1 and the air guide 13, reducing airflow leakage and preventing interference between the blade tip and other components, thus balancing fan efficiency and operational safety. In a preferred embodiment, B1=132mm, B2=15mm, B3=6mm, B4=2mm, and r1=11mm.

[0036] To further explain, by projecting along the rotation axis of the impeller 2, the leading edges 2411 of all blades 241 in the same group of blade assemblies 24 are connected with the axis O as the center to form the inner circle of the blade 241, and the diameter of the inner circle of the blade 241 is defined as the impeller inner diameter D2. The inner diameter of the reinforcing ring 23 is defined as the impeller outer diameter D1; The outer diameter of the reinforcing ring 23 is defined as the impeller diameter D3; Wherein, D1 / D2=1.15~1.25, D3=D1+2.8mm.

[0037] like Figure 5 As shown, the above-mentioned size ratio design can optimize the stress state of the blade 241, improve the aerodynamic performance of the impeller 2, and at the same time ensure the connection strength between the reinforcing ring 23 and the blade 241, and prevent the blade 241 from deforming. The optimal ratio can make the fan efficiency reach the best state.

[0038] In a preferred embodiment, D1 / D2 is set to 1.2, which allows the fan efficiency to reach its optimal state.

[0039] To further explain, the edges of the two air inlets 12 of the volute 1 extend into the interior of the volute 1 and gradually recede inward to form air guides 13. The ends of the air guides 13 enclose to form air guide openings 14. The air inlets 12 and the air guide openings 14 are both circular in shape, and the diameter of the air guide openings 14 is defined as D4. Among them, D4 / D2 = 1.03 to 1.05.

[0040] As Figure 1 and Figure 6 shown, the arc structure of the air guiding part 13 can guide the air flow to smoothly enter the impeller 2, reduce the resistance loss at the air inlet, and at the same time, the precise dimensional ratio can ensure the air intake efficiency and avoid the generation of eddy currents between the air guiding part 13 and the impeller 2.

[0041] For further illustration, when projected along the direction of the rotation axis of the impeller 2, each blade 241 in the blade assembly 24 has an inlet angle β1 and an outlet angle β2; Among them, β1 = 78° to 83°, β2 = 155° to 160°.

[0042] As Figure 8 shown, through the reasonable design of the inlet angle and outlet angle of the blade 241, the flow state of the air flow on the surface of the blade 241 can be optimized, the air flow separation and eddy current loss can be reduced, the work efficiency of the blade 241 can be improved, and at the same time, the noise generated by the air flow impact can be reduced.

[0043] In a preferred embodiment, β1 = 80°, β2 = 158°, which can achieve the best balance between the aerodynamic performance and the noise performance of the fan.

[0044] For further illustration, when projected along the direction of the rotation axis of the volute 1, the inner wall of the volute 1 forms a volute profile, and the volute profile is enclosed by an outlet section, a diffuser section, and a volute tongue section; The diffuser section includes a first arc segment, a second arc segment, a third arc segment, and a fourth arc segment connected in sequence. Define the starting end point of the first arc segment as the design point P1, the connection point of the first arc segment and the second arc segment as the design point P2, the connection point of the second arc segment and the third arc segment as the design point P3, the connection point of the third arc segment and the fourth arc segment as the design point P4, and the terminating end point of the fourth arc segment as the design point P5; The first arc segment is controlled and set by the design points P1 and P2, and the radius of the circle corresponding to the first arc segment is R1; The second arc segment is controlled and set by the design points P2 and P3, and the radius of the circle corresponding to the second arc segment is R2; The third arc segment is controlled and set by the design points P3 and P4, and the radius of the circle corresponding to the third arc segment is R3; The fourth arc segment is controlled and set by the design points P4 and P5, and the radius of the circle corresponding to the fourth arc segment is R4; Among them, R2 < R1 < R3 < R4, and the difference amplitude between any two adjacent circle radii does not exceed 10%.

[0045] like Figure 5 As shown, the segmented circular arc diffuser section design allows the airflow to diffuse smoothly inside the volute 1, gradually increasing the airflow pressure and reducing energy loss during the diffusion process. At the same time, the difference control between adjacent radii can avoid sudden changes in airflow velocity, further optimizing aerodynamic performance.

[0046] To further clarify, the straight-line distance between design point P3 and design point P5 is defined as the volute width Dh; Define the shortest straight-line distance from the design point P3 to the outer ring of the reinforcing ring 23 as A1; Define A as the shortest straight-line distance from the design point P5 to the outer ring of the reinforcing ring 23; Among them, 1.3≤Dh / D3≤1.4, 4.5≤A / A1≤5.5.

[0047] like Figure 5 As shown, the above-mentioned dimensional proportions ensure a reasonable width match between the volute 1 and the impeller 2, appropriate flow space for airflow within the volute 1, and uniform gap between the reinforcing ring 23 and the inner wall of the volute 1, reducing airflow leakage and frictional losses. In a preferred embodiment, Dh / D3=1.32, A / A1=5.03.

[0048] To further explain, the cochlear tongue segment includes a fifth arc segment; The two endpoints of the fifth arc segment are defined as design point P0 and design point P1, respectively. The radius of the circle corresponding to the fifth arc segment is the radius r of the volute tongue. The shortest straight-line distance between the fifth arc segment and the outer ring of the reinforcing ring 23 is defined as the volute tongue gap t; Where r < R2, 0.04 ≤ t / D3 ≤ 0.05.

[0049] like Figure 5 As shown, the circular arc structure and reasonable gap size of the volute tongue can effectively reduce eddy currents and backflow losses at the volute tongue, thereby reducing fan noise and preventing interference between the volute tongue and impeller 2, thus improving operational stability. In a preferred embodiment, t / D3 = 0.044.

[0050] To further explain, the blade 241 has a pressure surface 2415 and a suction surface 2416, which are arranged opposite to each other. Projected along the rotation axis of the impeller 2, the pressure surface 2415 and the suction surface 2416 respectively form a pressure flange profile and a suction flange profile; The pressure flange profile is the sixth arc segment, and the two endpoints of the sixth arc segment are defined as design point Q0 and design point Q1, respectively. The radius of the circle corresponding to the sixth arc segment is R5. The suction edge profile includes a seventh arc segment, an eighth arc segment, and a ninth arc segment connected sequentially. The seventh arc segment is located near the trailing edge 2413 of the blade, and the ninth arc segment is located near the leading edge 2411 of the blade. The starting endpoint of the seventh arc segment is defined as design point Q2, the connection point between the seventh and eighth arc segments is defined as design point Q3, the connection point between the eighth and ninth arc segments is defined as design point Q4, and the ending endpoint of the ninth arc segment is defined as design point Q5. The seventh arc segment is controlled by design points Q2 and Q3, and the radius of the circle corresponding to the seventh arc segment is R6. The eighth arc segment is controlled by design points Q3 and Q4, and the radius of the circle corresponding to the eighth arc segment is R7. The ninth arc segment is controlled by design points Q4 and Q5, and the radius of the circle corresponding to the ninth arc segment is R8. Among them, R8 < R5 < R7 < R6.

[0051] like Figure 8-9 As shown, the above-mentioned radius ratio design can adapt to the airflow trajectory from the leading edge 2411 to the trailing edge 2413 of the blade, making the profile of the suction surface 2415 conform to the airflow direction, reducing airflow separation and eddy current losses. Simultaneously, in conjunction with the pressure flange profile, it forms a reasonable blade aerodynamic profile, further improving the blade's working efficiency and reducing operating noise. In a preferred embodiment, R5 = 8.29 mm, R6 = 9.39 mm, R7 = 9.21 mm, and R8 = 3.57 mm.

[0052] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these equivalent variations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A multi-blade centrifugal fan, characterized in that, Includes a volute (1) and an impeller (2); The volute (1) has an air outlet (11) and two air inlets (12). The planes on which the two air inlets (12) are located are arranged in parallel relative to each other. The center of the two air inlets (12) is defined as the axis O', and the axis passing through the two axis O' is defined as the rotation axis of the volute (1). The impeller (2) includes a hub disk (21), a hub (22), two reinforcing rings (23) and two sets of blade assemblies (24). The hub (22) is fixedly connected to the center of the hub disk (21). The two sets of blade assemblies (24) are arranged alternately on two opposite sides of the hub disk (21), and each set of blade assemblies (24) is fixedly connected to the inner ring of one of the reinforcing rings (23). The blade assembly (24) includes a plurality of blades (241), and each blade (241) of the two sets of blade assemblies (24) has the same structure; the peripheral contour of the blade (241) is formed by the blade leading edge (2411), the blade top edge (2412), the blade trailing edge (2413), and the blade bottom edge (2414), and the plurality of blades (241) are evenly distributed at equal intervals on the corresponding side of the hub disk (21), and the bottom edge (2414) of each blade (241) is aligned with the corresponding side of the hub disk (21). The blades are fixedly connected on the side. The trailing edge (2413) of each blade (241) is flush with the outer edge of the hub disk (21). The trailing edge (2413) of each blade (241) is also fixedly connected to the inner ring of the corresponding reinforcing ring (23). The top edge (2412) of each blade (241) is smoothly connected to the top edge of the corresponding reinforcing ring (23). The top edge (2412) of each blade (241) and the top edge of the corresponding reinforcing ring (23) form a non-flush blade tip structure (25). The center of the hub disk (21) and the center of the two reinforcing rings (23) are overlapped and defined as the axis O of the impeller (2), and the axis passing through the axis O and perpendicular to the disk surface of the hub disk (21) is defined as the rotation axis of the impeller (2); The impeller (2) is installed inside the volute (1) according to a preset size ratio and structural parameters, and the shaft center O and shaft center O' are overlapped. The rotation axis of the impeller (2) is collinear with the rotation axis of the volute (1).

2. A multi-blade centrifugal fan according to claim 1, characterized in that, Both sets of blade assemblies (24) contain Z blades (241), and the stagger angle of the two sets of blade assemblies (24) on the two sides of the hub disk (21) is 360° / Z / 2, 39≤Z≤47.

3. A multi-blade centrifugal fan according to claim 1, characterized in that, Projecting along a direction perpendicular to the rotation axis of the volute (1), the axial distance between the highest and lowest points of a single non-flush blade top structure (25) is defined as B4; Define the axial distance between the highest points of the non-flush blade tip structure (25) of the two sets of blade assemblies (24) as B1; The axial distance between the highest point of the non-flush blade tip structure (25) of the two sets of blade assemblies (24) and the inner wall of the volute (1) is defined as B2; The axial distance between the lowest point of the non-flush blade tip structure (25) of the two sets of blade assemblies (24) and the end of the air guide (13) is defined as B3. The cross-sectional shape of the air guide (13) is an arc, and the radius of the arc of the air guide (13) is defined as r1; Wherein, 125mm≤B1≤155mm, 2mm≤B2-r1≤5mm, 4mm≤B3≤8mm, and B4=B3-(B2-r1).

4. A multi-blade centrifugal fan according to claim 1, characterized in that, Projecting along the rotation axis of the impeller (2), the leading edges (2411) of all blades (241) in the same set of blade assemblies (24) are connected with the axis O as the center to form the inner circle of the blade (241), and the diameter of the inner circle of the blade (241) is defined as the inner diameter of the impeller D2. The inner diameter of the reinforcing ring (23) is defined as the impeller outer diameter D1; The outer diameter of the reinforcing ring (23) is defined as the impeller diameter D3; Wherein, D1 / D2=1.15~1.25, D3=D1+2.8mm.

5. A multi-blade centrifugal fan according to claim 4, characterized in that, The edges of the two air inlets (12) of the volute (1) extend into the interior of the volute (1) and gradually recede inward to form air guides (13). The ends of the air guides (13) enclose to form air guides (14). The air inlets (12) and the air guides (14) are both circular in shape. The diameter of the air guides (14) is defined as D4. Wherein, D4 / D2 = 1.03~1.

05.

6. A multi-blade centrifugal fan according to claim 1, characterized in that, Projected along the direction of the rotation axis of the impeller (2), each blade (241) in the blade assembly (24) has an inlet angle β1 and an outlet angle β2; Wherein, β1 = 78°~83°, β2 = 155°~160°.

7. A multi-blade centrifugal fan according to claim 4, characterized in that, Projecting along the rotation axis of the volute (1), the inner wall of the volute (1) forms a volute profile, which is formed by the outlet section, the diffuser section and the volute tongue section. The diffuser section includes a first arc segment, a second arc segment, a third arc segment, and a fourth arc segment connected in sequence. The starting endpoint of the first arc segment is defined as design point P1, the connection point between the first and second arc segments is defined as design point P2, the connection point between the second and third arc segments is defined as design point P3, the connection point between the third and fourth arc segments is defined as design point P4, and the ending endpoint of the fourth arc segment is defined as design point P5. The first arc segment is controlled and set by the design point P1 and the design point P2, and the radius of the circle corresponding to the first arc segment is R1; The second arc segment is controlled and set by the design points P2 and P3, and the radius of the circle corresponding to the second arc segment is R2; The third arc segment is controlled and set by the design points P3 and P4, and the radius of the circle corresponding to the third arc segment is R3; The fourth arc segment is controlled and set by the design points P4 and P5, and the radius of the circle corresponding to the fourth arc segment is R4; Among them, R2 < R1 < R3 < R4, and the difference amplitude between the radii of any two adjacent circles does not exceed 10%.

8. A multi-blade centrifugal fan according to claim 7, characterized in that, Define the straight-line distance between the design point P3 and the design point P5 as the volute width Dh; Define the shortest straight-line distance from the design point P3 to the outer circle of the reinforcement ring (23) as A1; Define the shortest straight-line distance from the design point P5 to the outer circle of the reinforcement ring (23) as A; Among them, 1.3 ≤ Dh / D3 ≤ 1.4, 4.5 ≤ A / A1 ≤ 5.

5.

9. A multi-blade centrifugal fan according to claim 7, characterized in that, The volute tongue section includes a fifth arc segment; Define the two end points of the fifth arc segment as the design point P0 and the design point P1 respectively; The radius of the circle corresponding to the fifth arc segment is the volute tongue radius r; Define the shortest straight-line distance between the fifth arc segment and the outer circle of the reinforcement ring (23) as the volute tongue clearance t; Among them, r < R2, 0.04 ≤ t / D3 ≤ 0.

05.

10. A multi-blade centrifugal fan according to claim 1, characterized in that, The blade (241) has a pressure surface (2415) and a suction surface (2416), and the pressure surface (2415) and the suction surface (2416) are arranged oppositely; Projected along the direction of the rotation axis of the impeller (2), the pressure surface (2415) and the suction surface (2416) respectively form a pressure edge profile and a suction edge profile; The pressure edge profile is a sixth arc segment. Define the two end points of the sixth arc segment as the design point Q0 and the design point Q1 respectively, and the radius of the circle corresponding to the sixth arc segment is R5; The suction edge profile includes a seventh arc segment, an eighth arc segment and a ninth arc segment connected in sequence. The seventh arc segment is arranged near the trailing edge (2413) of the blade, and the ninth arc segment is arranged near the leading edge (2411) of the blade; Define the starting end point of the seventh arc segment as the design point Q2, the connection point of the seventh arc segment and the eighth arc segment as the design point Q3, the connection point of the eighth arc segment and the ninth arc segment as the design point Q4, and the terminating end point of the ninth arc segment as the design point Q5; The seventh arc segment is controlled and set by the design point Q2 and the design point Q3, and the radius of the circle corresponding to the seventh arc segment is R6; The eighth arc segment is controlled and set by the design point Q3 and the design point Q4, and the radius of the circle corresponding to the eighth arc segment is R7; The ninth arc segment is controlled and set by the design point Q4 and the design point Q5, and the radius of the circle corresponding to the ninth arc segment is R8; Among them, R8 < R5 < R7 < R6.

Images