A fan blade structure for reducing noise

Abstract

The invention relates to a blower blade structure for reducing noise, belonging to the technical field of blowers, comprising a shell, an impeller disk and a plurality of blades arranged in an equidistant array on the impeller disk, the impeller disk being mounted on the shell and provided with a connected air inlet and air outlet; an air guide channel is formed between adjacent blades, the end of the air guide channel close to the axis of the impeller disk being an air inlet area A, and the end away from the axis being an air outlet area B; the area of ​​the air inlet area A is larger than the area of ​​the air outlet area B; the blade is integrally formed by three circular arcs, namely, a flushing arc, a guide arc and a backflow arc, the two sides of the guide arc are respectively connected to the flushing arc and the backflow arc, the center of the guide arc is in the opposite direction to the center of the flushing arc and the backflow arc, the arc length ratio of the flushing arc, the guide arc and the backflow arc is 2.9:1.02:4.32, the curvature size is such that the flushing arc is smaller than the backflow arc and smaller than the guide arc, the impact of the airflow on the airflow in the impeller is reduced, the generation of vortex is reduced by reducing the gap between the blades, thereby reducing the noise.

Description

Technical Field

[0001] The invention belongs to the technical field of blowers, and in particular relates to a blower blade structure capable of reducing noise. Background Art

[0002] As consumers' requirements for product performance and quality continue to increase, manufacturers are also constantly improving their products and using various methods to bring consumers a better user experience. Among the various methods, reducing the noise of the fan inside the product can significantly reduce the noise during product operation, reduce the noise interference of users during use, and improve the user experience. This is especially important for various daily necessities such as cars, washing machines, microwave ovens, etc. These products are closely related to daily life, and reducing noise can help bring a better life experience to consumers.

[0003] In the structure of the blower, the impeller is one of the sources of noise. The rotation of the impeller drives the blades to rotate, stirring the air to generate airflow and play a role in heat dissipation. The process of vortex generation is that at the beginning, the fluid particles on the blades have already moved, while the nearby particles have not yet moved, so a velocity gradient is generated in the thin layer of fluid near the blades, forming a vortex layer. Later, due to the effect of viscosity, the fluid particles slightly farther away will also move, and the velocity gradient layer, i.e. the vortex layer, will diffuse.

[0004] The gap between the blades provides a path for the airflow to flow, which has a significant impact on the performance of the blower, such as air volume, air pressure, and noise. In a blower, in order to ensure efficiency, the usual practice is to set the gap between the two blades slightly larger, so that the fluid passing through the blades will also increase. However, due to the large gap, the airflow will generate eddy currents when passing through the gap between the blades, disrupting the correct air duct and increasing the degree of turbulence of the air flow. This phenomenon not only reduces the efficiency of the blower, but also generates noise.

[0005] Therefore, the blades need to be improved to improve the blower operating efficiency and reduce noise. Summary of the invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a blower blade structure with reduced noise, which solves the problem of high noise caused by the existing blowers in order to ensure working efficiency.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A fan blade structure for reducing noise, comprising a housing, an impeller disk, and a plurality of blades arranged in an equidistant array on the impeller disk, wherein the impeller disk is mounted on the housing, and the housing is provided with a connected air inlet and an air outlet; an air guide channel is formed between adjacent blades, an end of the air guide channel close to the axis of the impeller disk is an air inlet area A, and an end away from the axis is an air outlet area B; an area of ​​the air inlet area A is larger than an area of ​​the air outlet area B;

[0009] The blade is formed integrally by three circular arcs, namely, a scouring arc, a guide arc and a back-flow arc. The two sides of the guide arc are respectively connected to the scouring arc and the back-flow arc. The center of the guide arc is in the opposite direction to the center of the scouring arc and the back-flow arc. The arc length ratio of the scouring arc, the guide arc and the back-flow arc is 2.9:1.02:4.32, and the curvature of the scouring arc is smaller than that of the back-flow arc, which is smaller than that of the guide arc.

[0010] Preferably, the maximum straight-line distance S between the scouring arc and the guiding arc is 0.15 mm.

[0011] Preferably, the number of blades is 62, and the width of the air outlet area is 1.30 mm.

[0012] Preferably, the ratio of the area of ​​a single air guide channel to the cross-sectional area of ​​a single blade is 1:1.4.

[0013] Preferably, the wind outlet angle of a single blade is in the range of 130°-140°.

[0014] Preferably, the wind inlet angle of a single blade is between 15° and 30°.

[0015] Preferably, the height of the blade is higher than the height of the impeller disk, and a cavity is formed between the three arcs.

[0016] Preferably, a fixing ring is provided at one end of a plurality of the blades away from the impeller disk, and the fixing ring is located at the outer circumference of the blades.

[0017] The beneficial effects of the present invention are:

[0018] The reduction of the gap between the blades, that is, the reduction of the wind guide channel, helps to guide the airflow through the impeller more smoothly, reduces the impact of the backflow airflow on the airflow in the impeller, and reduces the generation of vortex by reducing the gap between the blades, thereby reducing noise. On the premise of reasonably setting the air guide channel, by setting the arc length ratio of the guide arc, the flushing arc and the back flow arc, the purpose is to increase the area of ​​the air inlet zone, thereby capturing more air, and achieve a smooth transition through the guiding effect of the back flow arc when the airflow enters the air outlet zone, thereby reducing the turbulence and vortex of the airflow, and reducing the generation of vortex and noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0020] Figure 1 It is a schematic diagram of the front view of the fan blade structure of a blower provided in one embodiment of the present invention;

[0021] Figure 2 A schematic diagram of a blade structure provided in one embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of an enlarged structure of a blade provided in one embodiment of the present invention;

[0023] Figure 4 A schematic diagram of a side view of a blower blade structure provided in one embodiment of the present invention;

[0024] Figure 5 A fluid simulation diagram of a blower blade provided in one embodiment of the present invention;

[0025] Legend: 1. Impeller disk; 2. Blades; 21. Scour arc; 22. Guide arc; 23. Backflow arc; 3. Air guide channel; 31. Air inlet area A; 32. Air outlet area B; 4. Fixed ring. DETAILED DESCRIPTION

[0026] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0027] like Figure 1-Figure 5As shown, a noise-reducing blower blade structure includes a housing, an impeller disk 1, and a plurality of blades 2 arranged in an equidistant array on the impeller disk 1. The impeller disk 1 is mounted on the housing and is provided with a connected air inlet and air outlet. An air guide channel 3 is formed between adjacent blades 2. The end of the air guide channel 3 close to the axis of the impeller disk is an air inlet area A31, and the end away from the axis is an air outlet area B32. The area of ​​the air inlet area A31 is larger than the area of ​​the air outlet area B32. The noise-reducing blower blade structure achieves the effect of noise reduction and efficient air supply through its unique blade 2 design and air guide channel 3 structure. When the blower is working, the rotation of the impeller disk 1 drives the blades 2 to rotate together. During the rotation process, the air inlet area A31 can capture and introduce more air due to its larger area, and the design of the air guide channel 3 guides the air to flow to the air outlet area B32; as the air flows, the air flow velocity in the air guide channel 3 gradually increases, and when entering the air outlet area B32, due to the relatively small area of ​​the air outlet area B32, the air flow is compressed, thereby increasing the pressure and speed of the air flow. This accelerated airflow can be more effectively pushed to the air outlet of the blower, thereby improving the air supply efficiency. In terms of noise reduction, the design of this structure can reduce the turbulence and vortex of the air flow, and through the reasonable spacing and shape of the blades 2, the impact and collision of the air when flowing in the air guide channel 3 are reduced, and the noise generated thereby is reduced. At the same time, the air flow in the air guide channel 3 is smoother, reducing the generation of turbulent noise.

[0028] Initial stage of vortex formation: air is sucked into the impeller, begins to contact with blade 2 and is pushed by blade 2. In the development stage, as the impeller rotates, air forms a rotating airflow under the push of blade 2, and gradually accumulates around the impeller to form a vortex, which gradually stabilizes and forms one or more obvious vortices. These vortices continue to exist as the impeller continues to rotate. The vortex has a certain impact on the performance and efficiency of the fan. They can increase the disturbance of the airflow and affect the air volume and noise level of the fan; the blade 2 is formed by three circular arcs, namely, the scouring arc 21, the guide arc 22 and the back flow arc 23. The two sides of the guide arc 22 are connected to the scouring arc 21 and the back flow arc 23 respectively, and the area of ​​the back flow arc 23 in the air inlet area A31 is larger than that of the guide arc 22; the scouring arc 21 is located at the leading edge of the blade 2, and its main function is to guide the air to smoothly enter the air guide channel 3. In terms of design, the scouring arc 21 should have a smoother transition to reduce the friction between the air and the leading edge of the blade 2, thereby reducing the noise generated by the impact of the airflow; the guide arc 22 connects the scouring arc 21 and the backflow arc 23, and its main function is to guide the airflow to flow smoothly in the air guide channel 3. The design of the guide arc 22 should take into account the flow characteristics and noise reduction requirements of the airflow to ensure that it can effectively reduce the turbulence and vortex of the airflow. The backflow arc 23 is located at the trailing edge of the blade 2 and plays a key role in the flow of the airflow in the outlet area B32. According to the principle, the area of ​​the backflow arc 23 in the air inlet area A31 is larger than the guide arc 22, aiming to increase the area of ​​the air inlet area, thereby capturing more air, and achieving a smooth transition through the guiding effect of the backflow arc 23 when the airflow enters the outlet area, thereby reducing the generation of vortices and noise.

[0029] The difference in area mainly reduces the frequency of vortex generation by affecting the path and velocity distribution of fluid flow. By increasing the area ratio in the backflow arc 23, the flow path of the fluid and the backflow arc 23 area becomes longer in the direction of wind flow, the contact between the fluid and the backflow arc 23 increases, and the velocity becomes lower, thereby reducing the generation of vortices. Since the generation of vortices is usually related to high-speed flow and sharp turns of the fluid, reducing the fluid velocity can reduce the generation of vortices. Secondly, the larger the width, the smaller the frequency of the generated vortex. According to the basic frequency formula of vortex noise:

[0030]

[0031] The longer the width L of the object's front surface projected on the vertical velocity plane, the smaller the frequency of eddy currents generated. This can reduce the frequency of eddy currents generated when the blower is running, thereby reducing the noise generated by the eddy currents.

[0032] f represents the frequency of eddy current noise (Hz); S_r is the Strouhal number, a dimensionless constant related to the Reynolds number, usually between 0.14 and 0.20, and generally 0.185; W1 is the relative speed between the gas and the blade 2 (m / s); L is the width of the projection of the positive surface of the object on the vertical velocity plane (m); i is the harmonic number, i=1, 2, 3, ..., n;

[0033] In summary, by setting the arc length ratio of the guide arc 22, the scouring arc 21 and the backflow arc 23, and the area of ​​the backflow arc 23 in the air inlet area A31 is larger than the guide arc 22, the purpose is to increase the area of ​​the air inlet area, thereby capturing more air, and achieving a smooth transition through the guiding effect of the backflow arc 23 when the airflow enters the air outlet area, reducing the generation of eddy currents and noise, reducing the turbulence and vortex of the airflow, and through the reasonable spacing and shape of the blades 2, reducing the impact and collision of the air when flowing in the air guide channel 3, thereby reducing the noise generated thereby.

[0034] In one embodiment, the center of the guide arc 22 is in the opposite direction to the center of the scouring arc 21 and the back flow arc 23, and the arc length ratio of the scouring arc 21, the guide arc 22 and the back flow arc 23 is 2.9:1.02:4.32, and the curvature is that the scouring arc 21 is smaller than the back flow arc 23 and smaller than the guide arc 22; because when the blade 2 rotates, the guide arc 22 is close to the axis of the impeller disk 1, after the rotation, the fluid first acts on the guide arc 22, and as the blade 2 continues to rotate, the fluid acting on the guide arc 22 is diverted by the guide arc 22 to the scouring arc 21 and the back flow arc 23, wherein the scouring arc 21 is located at the rear side of the rotation direction, and fluid will continuously act and scour the scouring arc 21 during rotation, while the back flow arc 23 is located at the front end of the rotation direction, and mainly receives and transfers the fluid from the guide arc 22, so that the fluid flow potential of the air guide channel 3 flows along the scouring arc 21 and the back flow arc 23;

[0035] The direction of its center is opposite to that of the scouring arc 21 and the backflow arc 23. This configuration helps to guide the fluid to transition more smoothly and reduce eddies and turbulence caused by sudden changes in the direction of the fluid. The arc length ratio of the scouring arc 21, the guide arc 22 and the backflow arc 23 is set to 2.9:1.02:4.32. This proportional design is based on the optimal ratio obtained through fluid dynamics simulation and experimental verification. It can minimize noise while ensuring equipment performance. The curvature of the scouring arc 21 is smaller than that of the backflow arc 23, and the curvature of the backflow arc 23 is smaller than that of the guide arc 22. This curvature design enables the fluid to gradually adapt to changes in flow velocity and flow direction when flowing through different arcs, reducing noise caused by sudden changes in flow velocity and sudden changes in flow direction.

[0036] Based on the previous embodiment, the fluid directly flushes the flushing arc 21 of the adjacent blade 2, but in the direction of the fluid flowing toward the blade 2, the flushing arc 21 mainly receives the fluid flowing in front and part of the fluid flushed on the guide arc 22. In this way, the flushing arc 21 is actually affected by the fluid from two directions. If the straight-line distance between the guide arc 22 and the flushing arc 21 is too long, it will cause the fluids in the two directions to interact with each other and generate eddies near the flushing arc 21. Therefore, the distance between the guide arc 22 and the flushing arc 21 also has a certain influence on the generation of noise. In one embodiment, the maximum straight-line distance S between the flushing arc 21 and the guide arc 22 is 0.15 mm. If the maximum straight-line distance The longer the distance S is, and the flow directions of the two fluids are opposite, so that when the fluids from two directions act, a surface force deviating from the scouring arc 21 will be generated, so that the flow rate and flow velocity on the surface of the scouring arc 21 are reduced, while the flow velocity outside the scouring arc 21 is large, and when flowing, the fluid on the surface of the scouring arc 21 will be driven to flow together, so that eddy currents are easily generated, and the pressure difference between the surface of the scouring arc 21 and the outside becomes larger. According to the sound power formula of eddy current noise, when the pipeline diameter, gas density and sound velocity are determined, the larger the pressure difference, the greater the sound power of the eddy current noise. The sound power of the eddy current noise is proportional to the sixth power of the airflow velocity, and can be approximately estimated by the following formula:

[0037]

[0038] W is the acoustic power of eddy current noise (W); k is an empirical constant obtained from experiments. For a circular pipe, the constant k = 2.5 × 10 -4 ; ΔP is the gas pressure difference before and after the obstacle (N / m 2 ); D is the pipe diameter (m); ρ is the gas density (kg / m 3 ); c is the speed of sound (m / s);

[0039] Therefore, the maximum straight-line distance S between the scouring arc 21 and the guide arc 22 is 0.15 mm, which can ensure a streamline transition between the scouring arc 21 and the guide, so that the fluid will not have a large pressure difference and fluctuation during the transition, thereby generating noise and causing the noise sound power to be too high.

[0040] In the design of fluid dynamics equipment, the number of blades 2 and the width of the air outlet area are key factors affecting the performance and noise level of the equipment. This embodiment aims to reduce the noise level by optimizing the number of blades 2 and the width of the air outlet area, while maintaining or improving the fluid dynamics performance of the equipment. In one embodiment, the number of blades 2 is 62, and the width of the air outlet area is 1.30 mm. Each impeller has an optimal number of blades 2. Too many blades 2 will increase friction resistance and energy consumption, while too few blades 2 will cause flow chaos and performance degradation. The number of blades 2 is optimized to 62. Based on the principles of fluid dynamics and experimental verification, the noise generated by the interaction between the blades 2 can be reduced while ensuring the stable flow of the fluid. The design of 62 blades 2 can provide a denser fluid channel, making the fluid more stable when passing through, reducing the noise generated by uneven flow rate; also based on fluid dynamics simulation and experimental verification, the width of the air outlet area is optimized to 1.30 mm. It can reduce the turbulence and eddy currents of the fluid in the outlet area while ensuring the smooth discharge of the fluid, thereby reducing noise. The width of 1.30mm allows the fluid to have a more stable flow state in the outlet area, avoiding the noise caused by excessive flow velocity or uneven flow. The optimized design has a significant effect in noise reduction through comparative experiments. Under the same working conditions, the equipment with 62 blades 2 and an outlet area width of 1.30mm reduces the noise by about 3 decibels compared with the equipment with traditional design. At the same time, the fluid dynamic performance of the equipment has also been improved; the reduction in the gap between the blades 2, that is, the reduction in the air guide channel 3, helps to guide the airflow through the impeller more smoothly, reduces the impact of the backflow airflow when the airflow is in the impeller, and reduces the generation of eddy currents by reducing the gap between the blades 2, thereby reducing noise.

[0041] The area ratio of the air guide channel 3 to the blade 2 is one of the key factors affecting the performance and efficiency of the equipment. By optimizing this ratio, the smooth flow of the fluid inside the equipment can be ensured, while reducing energy loss and noise generation. In one embodiment, according to the fluid dynamics characteristics and performance requirements of the equipment, the cross-sectional area of ​​a single blade 2 is determined to be S1. The size of the blade 2 area directly affects the fluid processing capacity and efficiency of the equipment. On the basis of determining the area S1 of the blade 2, the area S2 of the air guide channel 3 is optimized through fluid dynamics simulation and experimental verification, and the ratio of the area S2 of the single air guide channel 3 to the cross-sectional area of ​​the area S1 of the single blade 2 is set to 1:1.4, that is, S2=1.4*S1. Based on the principles of fluid dynamics and experimental data, the smooth flow of the fluid in the air guide channel 3 can be ensured, while reducing the friction and energy loss between the fluid and the blade 2. In the entire device, the blades 2 and the air guide channel 3 are arranged according to the optimized area ratio. Ensure that the area ratio between each wind guide channel 3 and the adjacent blades 2 is consistent to achieve uniform fluid distribution and efficient energy conversion; under the same wind speed (V = 10m / s) and fluid properties (such as air), the performance of the fluid dynamics equipment before and after optimization is tested. After long-term operation tests, it shows a significant performance improvement, and the fluid processing capacity is increased by 20%, from the original 100m 3 / s increased to 120m 3 / s, so that the wind turbine can process more wind energy in the same time, the efficiency is increased by 5%, from 80% to 85%, the energy conversion efficiency is improved, the operating cost is reduced, the noise level is reduced by 3dB, from 46dB to 43dB, which significantly improves the noise pollution problem in the surrounding environment and improves the user experience; in short, the optimized ratio of the area of ​​the wind guide channel 3 to the area of ​​the blade 2 allows the fluid to flow smoothly inside the device, reducing the friction and resistance between the fluid and the blade 2. This helps to improve the fluid handling capacity and efficiency of the device: the optimized design reduces the interaction and vibration between the fluid and the blade 2, thereby reducing the noise level of the device.

[0042] In one embodiment, the outlet angle of a single blade 2 is in the range of 130°-140°, and the size of the outlet angle directly affects the diffusion range and air supply distance of the airflow. A larger outlet angle means that the airflow has a wider diffusion range when leaving the air outlet, so that the wind can cover a longer distance; under the same air supply volume, the air flow rate at the air outlet can be effectively reduced by increasing the outlet angle. The reduction in flow rate can reduce the friction and turbulence between the airflow and the surrounding medium, thereby reducing the noise generated by the movement of the airflow. The outlet angle of blade 2 is in the range of 130°-140°, which is intended to ensure that the fluid has a suitable flow direction and velocity distribution at the outlet of blade 2 to achieve smooth fluid flow and efficient energy conversion.

[0043] In one embodiment, the inlet angle of a single blade 2 is between 15° and 30°. The inlet angle generally refers to the angle between the flow direction of the fluid (in this case, air) before entering the fan impeller or similar rotating device and the device axis or blade 2. Changes in the inlet angle will affect the initial velocity and pressure distribution of the fluid when it enters the impeller. A larger inlet angle may cause greater impact and disturbance of the fluid when it enters the impeller, thereby enhancing the intensity and complexity of the vortex. Changes in the inlet angle may also affect the main rotation direction of the vortex.

[0044] In one embodiment, the height of the blade 2 is higher than that of the impeller disk 1, and a cavity is formed between the three arcs, so that when the impeller disk 1 rotates, a large amount of airflow will not flow into the cavity, thereby generating noise in the cavity, and the cavity structure can also reduce the weight of the blower.

[0045] In one embodiment, a fixing ring is provided at one end of a plurality of blades 2 away from the impeller disk 1. The fixing ring is located at the outer periphery of the blade 2, which is equivalent to adding an annular support structure to the outer edge of the blade 2, thereby increasing the overall support area of ​​the blade 2. This design of increasing the support area effectively disperses the stress and deformation that may be generated by the blade 2 during the rotation process, and significantly improves the structural stability of the blade 2. When the blower is working, the blade 2 will be subjected to the centrifugal force caused by the high-speed rotation and the dynamic load caused by the impact of the airflow. The presence of the fixing ring can limit the excessive bending or twisting deformation of the blade 2 under the action of these forces, and maintain the shape and structural integrity of the blade 2. The fixing ring is usually made of high-strength materials with excellent tensile, compression and bending resistance. By tightly combining the fixing ring with the blade 2, the overall rigidity of the blade 2 can be significantly improved, so that it can better resist deformation and vibration when subjected to external forces.

[0046] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A blower blade structure for reducing noise, characterized in that: The invention comprises a housing, an impeller disk, and a plurality of blades arranged in an equidistant array on the impeller disk, wherein the impeller disk is mounted on the housing, and the housing is provided with a connected air inlet and an air outlet; an air guide channel is formed between adjacent blades, and an end of the air guide channel close to the axis of the impeller disk is an air inlet area A, and an end away from the axis is an air outlet area B; the area of ​​the air inlet area A is larger than the area of ​​the air outlet area B; The blade is formed integrally by three circular arcs, namely, a flushing arc, a guide arc and a back-flow arc. The two sides of the guide arc are respectively connected to the flushing arc and the back-flow arc. The center of the guide arc is in the opposite direction to the center of the flushing arc and the back-flow arc. The arc length ratio of the flushing arc, the guide arc and the back-flow arc is 2.9:1.02:4.

32. The curvature is such that the flushing arc is smaller than the back-flow arc and smaller than the guide arc. The height of the blade is higher than the height of the impeller disk. A cavity is formed between the three circular arcs. The ratio of the area of ​​a single air guide channel to the cross-sectional area of ​​a single blade is 1:1.

4. The wind outlet angle of a single blade is in the range of 130°-140°, and the wind inlet angle of a single blade is between 15°-30°.

2. A blower blade structure for reducing noise according to claim 1, characterized in that: The maximum straight-line distance S between the flushing arc and the guide arc is 0.15 mm.

3. A blower blade structure for reducing noise according to claim 1, characterized in that: The number of blades is 62, and the width of the air outlet area is 1.30 mm.

4. The blower blade structure for reducing noise according to claim 1, characterized in that: A fixing ring is arranged at one end of a plurality of blades away from the impeller disk, and the fixing ring is located at the outer periphery of the blades.

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