Impeller of multi-blade centrifugal fan

Abstract

The utility model discloses a multi-blade centrifugal fan impeller, and belongs to the technical field of fan impellers. Comprising a wheel disc, a plurality of sets of fan blades and a wheel cover, the fan blades are evenly arranged in the circumferential direction of the axis of the wheel disc and the axis of the wheel cover, and the fan blades are all located between the wheel disc and the wheel cover; the fan blade comprises a front edge, a blade body and a tail edge which are sequentially arranged, the front edge and the tail edge are asymmetrically arranged, and the radius of the front edge is larger than that of the tail edge. According to the utility model, flow separation is effectively inhibited, the performance of the fan is improved, and the running stability of the fan is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of fan impellers, in particular to a multi-blade centrifugal fan impeller. Background Art

[0002] The multi-blade centrifugal fan is a common aerodynamic mechanical device, also known as a multi-blade centrifugal fan or a multi-blade axial flow fan. The main components of the multi-blade centrifugal fan include a casing, an impeller, a duct, a driving device, etc., and are used in scenarios such as gas transportation, ventilation, air change, air supply or exhaust. It is usually applied in fields such as construction, industry, and environmental protection, and has the advantages of high efficiency, large air volume, low noise, energy conservation and environmental protection, providing effective ventilation, air change, heating and air treatment solutions for various scenarios.

[0003] The impeller is the core component in the multi-blade centrifugal fan. The impeller is driven to rotate by an external power such as an electric motor, and the rotating impeller pushes air or other gases to move through centrifugal force. For the convenience of industrial production and manufacturing, the traditional centrifugal impeller blade profile usually adopts a simple straight plate type. As shown in the Chinese invention patent with the application number 201510660495.5: Centrifugal Fan Impeller, it includes a wheel disc, blades arranged on the wheel disc and a blade ring, and a strengthening structure is arranged at the connection of the blades and the blade ring to reduce the equivalent stress of the impeller.

[0004] The prior art has the following defects: When the fluid passes through the straight plate type impeller blades, due to the simplicity of the blade shape, the contact area with the air flow is relatively small. At the same time, the straight blade shape does not provide a suitable guide, so that the air flow cannot form an ideal flow path on the blades, and it is easy to generate a turbulent area at the tail of the blades. The flow separation in the turbulent area will cause energy loss of the air flow, thereby weakening the impeller's control ability on the fan flow field, and then leading to a reduction in efficiency. Moreover, the flow field of the straight plate type impeller blades is very complex, often exacerbating the jet-wake phenomenon, thereby causing noise and vibration and affecting the operation stability of the fan. Therefore, there is room for improvement. Summary of the Utility Model

[0005] In order to solve the above-mentioned technical problems, the utility model provides a multi-blade centrifugal fan impeller to solve the technical problems that the existing centrifugal fan impeller has weak control ability on the fan flow field and poor operation stability of the fan.

[0006] The utility model is realized through the following technical solutions:

[0007] A multi-blade centrifugal fan impeller includes a hub, multiple groups of fan blades, and a shroud. The fan blades are evenly arranged circumferentially along the axis of the hub and the shroud, and all the fan blades are located between the hub and the shroud. The fan blades include a leading edge, a blade body, and a trailing edge arranged in sequence. The leading edge and the trailing edge are asymmetrically arranged, and the radius of the leading edge is greater than the radius of the trailing edge.

[0008] Preferably, a blunt head is provided at one end of the leading edge away from the blade body.

[0009] Preferably, a maximum thickness portion is provided at one end of the blade body close to the leading edge.

[0010] Preferably, the blunt head is connected to the position of the maximum thickness portion by a smooth curve.

[0011] Preferably, the blade body connects the leading edge and the trailing edge by a smooth curve, and a maximum camber portion is provided on the inner arc of the blade body.

[0012] Preferably, the angle between the trailing edge and the tangential direction of the impeller rotation is the outlet installation angle, and the outlet installation angle is set to 175°.

[0013] Preferably, the maximum thickness portion is provided at the 1 / 3 position of the fan blade.

[0014] Preferably, the fan blade is selected as a GOE370 airfoil blade.

[0015] The beneficial effects of the present utility model are as follows:

[0016] 1. Through the design of the asymmetric airfoil, the changes in the flow lines of the intake and exhaust are made smoother, reducing the resistance of the air flow when passing through the blades, thereby improving the efficiency, reducing the impact and vortex generation between the gas and the blades, and thus reducing the noise. At the same time, it is beneficial to avoid unnecessary damage to the impeller during operation, such as impact and friction, etc., thereby extending the service life of the impeller. The asymmetric design helps to form an accelerating flow channel. After the air flow enters the blade through the leading edge, because the radius of the leading edge is greater than the radius of the trailing edge, the blade diffuses the air flow, and then an accelerating flow channel is formed when the air flow leaves the trailing edge of the blade, which not only increases the kinetic energy but also improves the head of the fan.

[0017] 2. The setting of the blunt head can reduce the separation of the airflow on the blade surface, enabling the blade to transfer energy to the airflow more efficiently, thereby improving the power efficiency. At the same time, the blunt head can increase the stability of the blade, reducing the stall risk of the blade under different working conditions and enabling the blade to maintain good performance under various working conditions. The maximum thickness part increases the material usage of the blade, enhancing the anti-deformation and anti-fracture capabilities of the blade; the design of the curve allows the airflow entering the fan to be more smoothly guided to the maximum thickness part, reducing the turbulence phenomenon during the airflow movement, thereby reducing the operating resistance of the fan and improving the operating efficiency of the fan;

[0018] 3. By increasing the outlet angle, more efficient airfoils can be considered and used. At the same time, an effective acceleration flow channel can be formed, enabling the airflow entering the impeller to be better converted into kinetic energy, which can improve the total pressure efficiency of the fan and ultimately enhance the operating efficiency of the entire fan; setting the maximum thickness at the 1 / 3 position of the blade can increase the stiffness of the blade, and the airflow accelerates fastest at the first 1 / 3 position of the blade. Setting the maximum thickness here can effectively guide the airflow, effectively reducing the flow field resistance and improving the working efficiency of the fan; ensuring the stable operation of the fan and extending the service life of the fan.

[0019] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the background art, the drawings required for use in the embodiments of the present invention or the background art will be described below.

[0021] The drawings herein are incorporated into the specification and form a part of this specification. These drawings show embodiments that conform to the present disclosure and are used together with the specification to illustrate the technical solutions disclosed by the present invention.

[0022] Figure 1 It is a schematic diagram of the overall structure of the fan impeller of the present invention;

[0023] Figure 2 is Figure 1 an enlarged view of part A in

[0024] Figure 3 It is a schematic diagram of the overall structure of the fan blade.

[0025] Legend: 1. Hub; 2. Fan blade; 21. Leading edge; 22. Blade body; 23. Trailing edge; 3. Shroud; 4. Blunt head; 5. Maximum thickness part; 6. Maximum camber part. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To enable those skilled in the art to better understand the solution of the present utility model, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0028] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower",

[0029] "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the utility model product is customarily placed during use. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0030] In addition, the terms "horizontal", "vertical", "hanging", etc. do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0031] In the description of the present utility model, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0032] The following will describe in detail some embodiments of the present utility model in conjunction with the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0033] To further elaborate on the technical means and effects adopted by the present utility model to achieve the intended utility model purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation manner, structure, features, and effects of the present utility model as follows.

[0034] Please refer to Figures 1-3 , a multi - blade centrifugal fan impeller, which includes a wheel disc 1, multiple groups of fan blades 2, and a wheel cover 3. The fan blades 2 are evenly arranged circumferentially along the axis of the wheel disc 1 and the wheel cover 3, and the fan blades 2 are all located between the wheel disc 1 and the wheel cover 3; the fan blades 2 include a leading edge 21, a blade body 22, and a trailing edge 23 arranged in sequence. The leading edge 21 and the trailing edge 23 are asymmetrically arranged, and the radius of the leading edge 21 is greater than the radius of the trailing edge 23.

[0035] After starting the fan, the fan blades 2 start to rotate, driving air or other fluids to enter the fan from the leading edge 21. When the fluid enters the impeller, under the action of the rotating blades, it accelerates and moves circumferentially. The fluid experiences changes in speed and pressure in the channels between the blades, the speed increases, and the pressure also increases accordingly. After the fluid enters the central area of the wheel disc, due to the obstruction of the wheel disc 1 and the wheel cover 3, it changes direction and continues to flow circumferentially. The fluid continuously accelerates in the channel of the blade body 22 and is thrown out due to the centrifugal force when it moves to the trailing edge 23, entering the exhaust duct or being directly discharged into the environment.

[0036] The design of the asymmetric airfoil makes the changes in the flow lines of the inlet and outlet air more smooth, reducing the resistance when the air flow passes through the blades, thereby improving the efficiency; in the case of the same impeller diameter, compared with the symmetric airfoil, the asymmetric airfoil can handle a larger air flow volume, so the air volume is increased; due to the use of the asymmetric airfoil, the process of gas entering and leaving the impeller is more stable, greatly reducing the collision and vortex generation between the gas and the blades, thereby reducing the noise; the asymmetric airfoil is beneficial to avoiding unnecessary damage to the impeller during operation, such as impact and friction, etc., thus extending the service life of the impeller.

[0037] The leading edge 21 of the blade directly contacts the incoming air flow first, and its shape and direction have a great influence on the guiding of the air flow. The design of appropriately increasing the radius of the leading edge 21 can reduce the fluid resistance and maintain the stability of the air flow; the trailing edge 23 part is mainly to optimize the state of the air flow when it leaves the blade. The design of appropriately reducing the radius of the trailing edge 23 can minimize the generation of air flow separation and vortices, thereby improving the output efficiency of the fan. The asymmetric design helps to form an accelerating flow channel. After the air flow enters the blade through the leading edge 21, because the radius of the leading edge 21 is greater than the radius of the trailing edge 23, the blade causes the diffusion of the air flow, and then an accelerating flow channel is formed when the air flow leaves the trailing edge 23 of the blade, which not only increases the kinetic energy but also improves the head of the fan.

[0038] If the leading edge 21 is designed too sharply, it may cause a regional high-speed flow of the fluid at the contact point, which will generate vortices at the inlet and result in energy loss. On the contrary, if the leading edge 21 is designed too flat, the fluid may overflow when entering, which will also cause energy loss. Based on this, in one embodiment, a blunt head portion 4 is provided at one end of the leading edge 21 away from the blade body 22. The setting of the blunt head portion 4 can reduce the separation of the air flow on the blade surface. When the air flow adheres to the blade surface, the blade can transfer energy to the air flow more efficiently, thereby improving the power efficiency. At the same time, the blunt head portion 4 can increase the stability of the blade because it can reduce the pressure difference applied to the blade and make the flow velocity distribution of the air flow on the blade more uniform. This can reduce the stall risk of the blade under different working conditions, reduce the situation where the fan efficiency is reduced due to stall, and avoid the possible structural problems caused by stall, so that the blade can maintain good performance under various working conditions. In addition, setting the blunt head portion 4 at the leading end of the blade can increase the bending and torsion resistance of the blade, improve the structural strength and stability of the blade, and prevent the blade from deforming or breaking under the conditions of high-speed rotation and large air flow.

[0039] In order to enhance the anti-deformation ability and anti-fracture ability of the blade, and at the same time effectively control the flow of the air flow on the blade surface, based on this, in one embodiment, a maximum thickness portion 5 is provided at one end of the blade body 22 close to the leading edge 21. The blade body 22 is the main part of the blade, and its shape and thickness affect the efficiency and noise of the fan. The design of the blade body 22 and the position setting of its maximum thickness portion 5 are to achieve the best distribution of the air flow on the blade surface while ensuring the structural strength, so as to obtain the highest efficiency. The maximum thickness portion 5 increases the material usage of the blade, makes the blade stronger and more stable when bearing the centrifugal force and other mechanical loads generated during the operation of the fan, and enhances the anti-deformation ability and anti-fracture ability of the blade; setting the maximum thickness portion 5 close to the leading edge 21 can increase the bypass ratio of the blade, help improve the lift and reduce the drag, thereby improving the performance of the fan; by adjusting the position and shape of the maximum thickness portion 5, the flow of the air flow on the blade surface can be effectively controlled, making its distribution uniform, reducing vortices and air flow separation; by optimizing the shape of the blade and the design of the position of the maximum thickness portion 5, the noise generated during the operation of the fan can be effectively reduced.

[0040] In order to reduce the operating resistance of the fan and improve the operating efficiency of the fan, based on this, in one embodiment, the blunt head 4 is connected to the position of the maximum thickness part 5 by a smooth curve. Connecting the blunt head 4 to the maximum thickness part 5 by a smooth curve allows air to transition naturally and smoothly to the maximum thickness part 5 of the blade. The gentle transition can reduce the turbulence phenomenon during air flow, thereby reducing noise and improving efficiency; the curve design enables the air flow entering the fan to be more smoothly guided to the maximum thickness part 5, reducing the turbulence phenomenon during air flow, thus reducing the operating resistance of the fan and improving the operating efficiency of the fan; the appropriate curve design can ensure that the air flow clings to the blade surface, reducing the phenomenon of flow separation; the design of the smooth curve can control the pressure distribution of the air flow on the blade, making it more uniform, which can further increase the lift and working efficiency of the fan; at the same time, it makes the air flow on the blade surface more smooth, effectively reducing the fan noise and vibration caused by vortices and turbulence.

[0041] In order to effectively reduce flow separation and increase the strength of the blade at the same time, based on this, in one embodiment, the blade body 22 is connected to the leading edge 21 and the trailing edge 23 by a smooth curve, and a maximum camber part 6 is arranged on the inner arc of the blade body 22. Connecting the blade body 22 to the leading edge 21 and the trailing edge 23 by a smooth curve enables the air flow entering the fan to flow more smoothly on the blade surface, and can effectively reduce flow separation, increase the air volume, and reduce the operating noise; it ensures the smooth flow of the air flow on the blade surface, reduces the leakage loss, and improves the efficiency of the entire fan. At the same time, the camber design of the blade can increase the strength of the blade, preventing bending or even breaking due to large forces. By adjusting the position and value of the maximum camber, the acceleration degree and position of the air flow on the blade can be effectively changed, thereby optimizing the aerodynamic performance. The appropriate maximum camber position and maximum camber value can be selected according to actual production requirements to achieve precise control of the air flow and meet the required performance indicators.

[0042] In order to effectively form an accelerating flow path and enable more efficient airfoils to be considered and used, based on this, in one embodiment, the angle between the trailing edge 23 and the tangential direction of the impeller rotation is the outlet installation angle, and the outlet installation angle is set to 175°. As the outlet angle increases, the total pressure efficiency increases, and the maximum acceleration position coefficient x is all 1. The range of the maximum acceleration coefficient μ of high efficiency gradually expands, which enables more efficient airfoils to be considered and used. Because such airfoils usually have good aerodynamic characteristics and can maintain high efficiency at a relatively large outlet installation angle; due to the increase in the outlet installation angle, an effective accelerating flow path can be formed, enabling the air flow entering the impeller to be better converted into kinetic energy, thereby improving the total pressure efficiency of the fan and ultimately enhancing the operating efficiency of the entire fan; the increase in the outlet installation angle is beneficial to improving the aerodynamic performance of the fan. The flow direction of the air flow at the outlet is closer to the tangential direction of the impeller, which can reduce the vortex loss caused by the sudden change in the air flow direction and is beneficial to improving the working efficiency and stability of the fan.

[0043] In order to effectively guide the air flow and reduce the flow field resistance, based on this, in one embodiment, the maximum thickness part 5 is arranged at the 1 / 3 position of the fan blade 2. Setting the maximum thickness at the 1 / 3 position of the blade can increase the stiffness of the blade, counteract the blade deformation and fatigue caused by the self-weight of the blade and the impact force of the air flow on the blade during the operation of the fan, and ensure the stable operation of the fan; fluid dynamics shows that the air flow accelerates fastest at the first 1 / 3 position of the blade. Setting the maximum thickness here can effectively guide the air flow, effectively reduce the flow field resistance, and improve the working efficiency of the fan; setting the maximum thickness part 5 at the 1 / 3 position can reduce the noise generated during the operation of the fan by optimizing the blade shape, reduce the vibration of the fan structurally, ensure the stable operation of the fan, and extend the service life of the fan.

[0044] In order to efficiently convert wind energy into mechanical energy and improve the stability of the fan, based on this, in one embodiment, the fan blade 2 is selected as the GOE370 airfoil blade. The GOE370 airfoil has very excellent aerodynamic characteristics within a certain range of attack angles, including a relatively high lift coefficient and a relatively low drag coefficient, which enables it to efficiently convert wind energy into mechanical energy; the GOE370 airfoil has good stability and performs excellently when the wind speed changes greatly. Due to the characteristics of its airfoil shape, it can maintain good performance under a wide range of working conditions; in terms of design, the GOE370 airfoil can effectively reduce the noise generated during the operation of the fan and improve the user experience; the GOE370 airfoil design takes into account a wide range of applications and can better adapt to both large industrial fans and small residential ventilation equipment. Under the design working conditions, the total pressure efficiency of the prototype fan is 42.28%. After the outlet angle of the fan blade 2 is changed to 175° by this method, the blade adopts the GOE370 airfoil, and the inner and outer diameters of the impeller and the number of blades are reduced, and the total pressure efficiency is increased to 54.28%.

[0045] As described above, it is only the preferred embodiment of the present utility model, and it does not impose any formal restrictions on the present utility model. Although the present utility model has been disclosed above with the preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the disclosed technical content without departing from the technical solution of the present utility model. However, as long as it does not depart from the technical solution content of the present utility model, any brief modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. A multi-blade centrifugal fan impeller, characterized in that: The invention comprises a wheel disc (1), a plurality of groups of fan blades (2) and a wheel cover (3), wherein the fan blades (2) are evenly arranged along the circumferential direction of the axis of the wheel disc (1) and the wheel cover (3), and the fan blades (2) are all located between the wheel disc (1) and the wheel cover (3); the fan blades (2) comprise a leading edge (21), a blade body (22) and a trailing edge (23) which are arranged in sequence, the leading edge (21) and the trailing edge (23) are arranged asymmetrically, and the radius of the leading edge (21) is greater than the radius of the trailing edge (23).

2. A multi-blade centrifugal fan impeller according to claim 1, characterized in that: A blunt head (4) is provided at one end of the leading edge (21) away from the blade body (22).

3. A multi-blade centrifugal fan impeller according to claim 2, characterized in that: A maximum thickness portion (5) is provided at one end of the blade body (22) close to the leading edge (21).

4. A multi-blade centrifugal fan impeller according to claim 3, characterized in that: The blunt head portion (4) is connected to the maximum thickness portion (5) in a smooth curve.

5. The multi-blade centrifugal fan impeller according to claim 1, characterized in that: The blade body (22) connects the leading edge (21) and the trailing edge (23) with a smooth curve, and a maximum curvature portion (6) is provided inside the circular arc of the blade body (22).

6. The multi-blade centrifugal fan impeller according to claim 1, characterized in that: The angle between the trailing edge (23) and the tangential direction of the impeller rotation is the outlet installation angle, and the outlet installation angle is set to 175°.

7. The multi-blade centrifugal fan impeller according to claim 3, characterized in that: The maximum thickness portion (5) is arranged at the 1 / 3 position of the fan blade (2).

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