A high air volume and low noise fan blade, fan and blade design method
Through the design of large-fold corner blades and small hole control technology, the problem of increased noise and power consumption when the fan increases air volume is solved, the effect of high air volume and low noise is achieved, and the performance and efficiency of the fan is improved.
Patent Information
- Application Number
- CN202111161340.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-09-30
- Publication Date
- 2024-12-06
- Estimated Expiration
- 2041-09-30
AI Technical Summary
Existing fans cannot reduce noise and power consumption while increasing air volume. Traditional design methods such as increasing blade chord length and folding angle are already close to the limit, which cannot meet the heat dissipation needs of high-performance electronic components.
The large-fold corner blade design is adopted. By setting multiple rows of small holes on the fan blade, fluid separation is controlled, airflow velocity and static pressure are increased, flow separation is delayed, and noise and power consumption are reduced.
At lower speeds, significantly increase air volume and air pressure, reduce aerodynamic noise and power consumption, improve P-Q performance, reduce noise by 3~7dB, and reduce power consumption by 2%~5%.
Smart Images
Figure CN113757170B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of fans, and in particular to a high-air-volume and low-noise fan blade, a fan and a design method for the blade. Background Art
[0002] With the high performance of electronic products and the increasing attention paid to energy saving and noise reduction by the society, fans, as one of the main components of air-cooling heat dissipation systems, have put forward more stringent requirements on their cooling and noise performance. In order to meet the higher heat dissipation requirements of electronic components, the current way to significantly increase the fan air volume is still mainly to increase the speed. However, the high-speed rotation of the fan will inevitably directly lead to an increase in noise and power consumption. Therefore, fan design technology that meets high air volume, low power consumption and low noise at the same time has become an important research direction for domestic and foreign scholars and fan industry workers.
[0003] In the prior art, taking the axial flow fan for servers as an example, its noise is mainly composed of aerodynamic noise, mechanical noise and electromagnetic noise. Under normal conditions, compared with aerodynamic noise, the intensity of mechanical noise and electromagnetic noise is low and can be ignored. Aerodynamic noise is mainly composed of rotational noise and eddy current noise. Rotational noise is a discrete noise formed by the periodic flapping of the surrounding air by the fan blades, causing gas pressure pulsation. Its intensity is mainly affected by the rotation speed and is proportional to the sixth power of the rotation speed. Eddy current noise is mainly manifested as broadband noise formed by the eddy current falling off the surface of the fan blades. Its intensity is mainly affected by the scale and intensity of flow separation on the surface of the fan blades. At present, in the design of axial flow fans, increasing air volume and air pressure can be achieved mainly by increasing the fan blade load and increasing the fan blade speed. However, the inherent reverse pressure gradient in the fan blade flow channel makes it easy for low-energy fluids to separate. Further increase in the fan blade load will aggravate the occurrence of this phenomenon, and even cause the fan to stall, resulting in a sharp increase in aerodynamic losses, a sharp drop in aerodynamic efficiency, a sudden increase in power consumption, and a sharp increase in eddy current noise. In recent years, fan manufacturers have used the method of increasing the blade chord length and blade turning angle at the same time to increase the fan blade load, but due to the limited increase in the chord length, the improvement effect has reached its limit. Therefore, the current mainstream way to significantly increase the air volume is still to rely on the increase in speed. However, as mentioned above, the increase in fan speed will directly lead to a sharp increase in rotational noise, and at the same time increase the fan power consumption. At present, fan manufacturers have tried to adopt unequal pitch fan blade design methods, starting from breaking the periodic flapping angle of the fan blade to the flow field, reducing rotational noise, and have achieved certain results. However, since this method destroys the original flow field distribution inside the fan blade, it will have a certain impact on the PQ performance, and it also poses a great challenge to the dynamic balance design of the fan, resulting in this design method is also relatively limited.
[0004] Therefore, some of the traditional optimization and new design methods currently used still cannot meet the fans required by the next generation of high-performance and high-heat electronic components, and some other new fan blade design technologies still need to be explored. Summary of the invention
[0005] In order to overcome the deficiencies in the above-mentioned prior art, the present invention provides a high-air-volume and low-noise fan blade and a design method for a fan and a fan blade to meet the requirements of high-performance and high-heat-generating electronic components for fans.
[0006] On the one hand, the present invention provides a high-air-volume, low-noise fan blade to solve the above-mentioned technical problems. The technical solution adopted is: the blade includes a blade body, and the blade body is formed by stacking large-angle blade shapes (because the blade body is a three-dimensional shape, and the large-angle blade shape is a two-dimensional shape, which contains multiple large-angle blade shapes, it is described as a blade body formed by stacking large-angle blade shapes), and the two fan surfaces on the blade body are the suction surface and the pressure surface, respectively. The suction surface and the pressure surface have different curvatures. The starting position of fluid separation on the suction surface is the separation starting point, and the separation starting point is located in the middle and rear part of the suction surface. At least two rows of small holes are opened on the blade body, and the small holes are all located upstream of the separation starting point. The small holes penetrate the pressure surface and the suction surface. Furthermore, three rows of small holes are arranged on the blade body, and each row includes a plurality of small holes arranged at intervals. The high-speed fluid flowing through the first row of holes controls the flow before flow separation occurs. As the fluid moves downstream, the high-speed fluid flowing through the second and third rows of holes continues to provide energy to the low-energy fluid, which can effectively suppress the flow separation size and intensity on one side of the suction surface. Furthermore, the blade turning angle of the fan blade body is θ, and the value range of θ is 20º ~65º.
[0007] The increase in air volume mainly depends on the increase in rotation speed, which brings about the increase in aerodynamic noise and power consumption. If the blade turning angle θ at different cross-sections is appropriately increased by 5º ~15º, the fan blade's ability to do work on the airflow can be significantly enhanced, that is, the airflow velocity and static pressure can be significantly improved. However, the increase in adverse pressure gradient will cause a sudden increase in the degree of flow separation on the suction side, and the separation point will move toward the leading edge of the blade, which can easily cause blockage of the flow channel between the fan blades and cause the fan to stall. By drilling holes from the pressure side to the suction side at the upstream position of the flow separation starting point, the high-speed fluid on the pressure side can flow from the small holes to the suction side, which can not only blow away the low-energy fluid on the suction side, but also provide momentum for the low-energy fluid on the suction side, thereby enhancing the ability of these low-energy fluids to resist the adverse pressure gradient, and moving the starting position of the flow separation toward the trailing edge, effectively delaying the flow separation phenomenon in the fan blade flow channel.
[0008] On the other hand, the present invention provides a high air volume and low noise fan, comprising the above-mentioned fan blades, a fan seat and a driving device, wherein the fan blade body has a plurality of blade bodies, the plurality of blade bodies are evenly distributed on the fan seat, and the fan seat is connected to the driving device. The driving device drives the fan seat to rotate to realize the rotation of the fan blade.
[0009] In addition, the present invention also provides a design method for a high-air-volume and low-noise fan blade, comprising the following steps:
[0010] A1: Increase the blade turning angle;
[0011] A2: By starting the hole design at the upstream position of the separation starting point; a total of three rows of holes are opened, and the high-speed fluid on the pressure side flows into the suction side through the holes due to the higher static pressure to blow away the low-energy fluid on the suction side, and at the same time provide momentum for the low-energy fluid. The high-speed fluid flowing through the first row of holes controls the flow before the flow separation occurs. As the fluid moves downstream, the high-speed fluid flowing through the second and third rows of holes continues to provide energy for the low-energy fluid, which can effectively suppress the flow separation size and intensity on the suction side.
[0012] A3: Design the size and array layout of the small holes;
[0013] A4: Determine the geometric position of each small hole on the fan blade body;
[0014] A5: Determine the opening direction (i.e. the blowing direction from the pressure side to the suction side) and the diameter of the small hole;
[0015] The above steps are not limited to the order;
[0016] Among them, according to the starting position and flow separation range of the flow separation at the suction surface of the fan, the approximate value ranges of the radial position l and the chordal position SHOLE of the small hole are determined, and according to the blowing flow rate required to suppress the fan flow separation and the degree of mixing between the blowing airflow of the small hole and the flow in the separation zone, the approximate value ranges of the aperture d, the line-surface angle α and the direction angle β of the small hole are determined. Then, a detailed parametric analysis is carried out on the above parameters to explore the different effects of different parameter values on the fan flow field, and finally the specific values of the above parameters are determined, thereby completing the design of the small hole array.
[0017] Furthermore, parameters are defined during the design process.
[0018] Furthermore, h represents the blade height, the radial position l of the hole is determined by the relative blade height (l / h), and the chord position SHOLE of the hole is determined by the relative arc length position of the suction surface under the blade height where the hole outlet center point (point A) is located (SHOLE / SSS). After these two parameters are determined, the geometric position of each small hole is determined.
[0019] Furthermore, in the process of defining the opening direction of the small hole, a reference plane must be selected first, the angle between the hole center line and the reference plane must be determined, and then the angle between the projection of the line on the reference plane and the reference line must be determined.
[0020] Furthermore, straight line b represents a straight line in space passing through point A and parallel to the fan rotation axis. The plane where straight line b is located and perpendicular to the radius corresponding to point A is selected as the reference plane S. The angle between the axis of the small hole (i.e., the blowing direction of the small hole) k and the reference plane S is defined as the line-plane angle α. The angle between the projection k' of the axis of the small hole on the reference plane S and straight line b is defined as the direction angle β. After these two angles are determined, the blowing direction of the small hole is fixed.
[0021] Furthermore, for different types of fans, the size and array arrangement of the small holes will change due to the different airflow mechanisms in the flow channels.
[0022] It can be seen from the above technical solutions that the present invention has the following advantages:
[0023] 1. By adopting a large fold angle blade shape combined with a blade structure with openings from the pressure side to the suction side, the blade load is effectively increased, thereby improving the ability of the blade to work on the airflow, so that the kinetic energy and static pressure of the gas are further increased, so that a larger air volume and higher air pressure can be obtained at a relatively low speed, thereby reducing aerodynamic noise and fan power consumption.
[0024] 2. It can improve the PQ performance in the fan working area by 5%~10%, reduce the overall noise by 3~7dB, and reduce power consumption by 2%~5%, or even more. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.
[0026] Figure 1-Figure 8 It is a schematic diagram of the structure and design of the fan blade design process in a specific implementation manner of the present invention.
[0027] In the figure, 1. separation starting point position, 2. small hole, 3. separation area, 4. airflow. DETAILED DESCRIPTION
[0028] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in this specific embodiment. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent. Specific implementation method 1
[0030] like Figure 1-Figure 8 As shown, this specific embodiment provides a high-air-volume, low-noise fan blade, which includes a blade body, which is formed by stacking large-angle blade profiles, and the two fan surfaces on the blade body are respectively the suction surface and the pressure surface, and the suction surface and the pressure surface have different curvatures. The starting position of fluid separation on the suction surface is the separation starting point, and the separation starting point is located in the middle and rear part of the suction surface. At least two rows of small holes 2 are provided on the blade body, and the small holes 2 are all located upstream of the separation starting point, and the small holes 2 pass through the pressure surface and the suction surface. Further, three rows of small holes 2 are provided on the blade body, and each row includes a plurality of small holes 2 arranged at intervals. The high-speed fluid flowing through the first row of holes controls the flow before the flow separation occurs. As the fluid moves downstream, the high-speed fluid flowing through the second and third rows of holes continues to provide energy to the low-energy fluid, which can effectively suppress the flow separation size and intensity on one side of the suction surface. Further, the blade profile turning angle of the blade body is θ, and the value range of θ is 20º ~65º. The increase in air volume mainly depends on the increase in rotation speed, which brings about the increase in aerodynamic noise and power consumption. If the blade turning angle θ at different cross-sections is appropriately increased by 5º ~15º, the fan blade's ability to do work on the airflow can be significantly enhanced, that is, the airflow velocity and static pressure can be significantly improved. However, the increase in adverse pressure gradient will cause a sudden increase in the degree of flow separation on the suction side, and the separation point will move toward the leading edge of the blade, which can easily cause blockage of the flow channel between the fan blades and cause the fan to stall. By drilling holes from the pressure side to the suction side at the upstream position of the flow separation starting point, the high-speed fluid on the pressure side can flow from the small hole 2 to the suction side, which can not only blow away the low-energy fluid on the suction side, but also provide momentum for the low-energy fluid on the suction side, thereby enhancing the ability of these low-energy fluids to resist the adverse pressure gradient, and moving the starting position of the flow separation toward the trailing edge, effectively delaying the flow separation phenomenon in the fan blade flow channel. Specific implementation method 2
[0032] This specific embodiment provides a high air volume and low noise fan (see Figure 3 , Figure 4 , Figure 7), including the fan blades in the specific embodiment 1, and also including a fan seat and a driving device, the fan blade body has multiple, the multiple fan blade bodies are evenly distributed on the fan seat, and the fan seat is connected to the driving device. The fan seat is driven by the driving device to rotate to realize the rotation of the fan blade. Specific implementation method 3
[0034] This specific implementation provides a design method for a fan blade with high air volume and low noise.
[0035] like Figure 1 As shown, θ is defined as the blade turning angle. In order to suppress the flow separation caused by the adverse pressure gradient on the blade surface, the blade turning angle θ at different cross sections is generally limited. The blade turning angle shows an increasing trend from the top to the root of the blade, and the range is roughly between 20º and 50º. Therefore, the increase in air volume mainly depends on the increase in speed, and the problems brought about by it are the increase in aerodynamic noise and power consumption. If the blade turning angle θ at different cross sections is appropriately increased by 5º ~15º, the ability of the blade to do work on the airflow can be significantly enhanced, that is, the airflow velocity and static pressure can be significantly improved. However, the enhancement of the adverse pressure gradient will cause a sudden increase in the degree of flow separation on the suction side, and the separation point will move toward the leading edge of the blade, which is easy to cause blockage of the flow channel between the blades, resulting in fan stall. By starting to punch holes from the pressure side to the suction side at the upstream position of the flow separation starting point, as shown in Figure 2 As shown, the high-speed fluid on the pressure side can flow from the small hole 2 to the suction side, which can not only blow away the low-energy fluid on the suction side, but also provide momentum for the low-energy fluid on the suction side, thereby enhancing the ability of these low-energy fluids to resist the adverse pressure gradient, and moving the starting position of the flow separation toward the trailing edge, effectively delaying the flow separation phenomenon in the fan blade flow channel.
[0036] like Figure 3 As shown in the figure, during the operation of the fan, the gas enters the blade from the leading edge LE of the fan, then enters the blade flow channel, and finally flows out of the blade through the trailing edge TE of the blade. When the gas flows through the blade, due to the different curvatures of the suction surface and the pressure surface, the corresponding static pressures of the gas on both sides are different. The static pressure of the fluid on the pressure surface PS side will be greater than that on the suction surface SS side. The low-energy fluid on the suction surface is very likely to undergo flow separation under the action of the adverse pressure gradient. Flow separation usually occurs in the middle and rear part of the suction surface. Therefore, Figure 4As shown, based on the large turning angle blade design, the hole design is started at the upstream position of the separation starting point, and a total of three rows of holes are opened. The high-speed fluid on the pressure side flows into the suction side through the holes due to its higher static pressure, and blows out the low-energy fluid on the suction side, while providing momentum for the low-energy fluid. The high-speed fluid flowing through the first row of holes controls the flow before the flow separation occurs. As the fluid moves downstream, the high-speed fluid flowing through the second and third rows of holes continues to provide energy for the low-energy fluid, which can effectively suppress the flow separation size and intensity on the suction side.
[0037] In the process of designing the size and array layout of the small holes 2, it is necessary to determine the geometric position of each hole on the fan blade, the opening direction (i.e., the blowing direction from the pressure side to the suction side) and the diameter of the small hole 2, because the change of these parameters determines the effect of the opening design on the flow field inside the fan blade. Therefore, before introducing the design process, the above parameters are defined first, and the definition method is as follows: Figure 5 As shown, h represents the blade height of the fan blade, and the radial position l of the hole is determined by the relative blade height (l / h), as shown in Figure 6 As shown in the figure, the chord position SHOLE of the hole is determined by the relative arc length position (SHOLE / SSS) of the suction surface under the blade height where the center point of the hole outlet (point A) is located. After these two parameters are determined, the geometric position of each small hole 2 is determined; in the process of defining the opening direction of the small hole 2, a reference plane must be selected first, the angle between the hole center line and the reference plane must be determined, and then the angle between the projection of the line on the reference plane and the reference line must be determined. Therefore, if Figure 7 As shown, straight line b represents a straight line in space passing through point A and parallel to the fan rotation axis. The plane where straight line b is located and perpendicular to the radius corresponding to point A is selected as the reference plane S. The angle between the axis k of small hole 2 (i.e., the blowing direction of small hole 2) and the reference plane S is defined as the line-plane angle α. The angle between the projection k' of the axis of small hole 2 on the reference plane S and straight line b is defined as the direction angle β. After these two angles are determined, the blowing direction of small hole 2 is fixed. Figure 8As shown, d represents the aperture of small hole 2. The specific design process of the small hole 2 array is as follows: according to the starting position and flow separation range of the flow separation at the suction surface of the fan, determine the approximate value range of the radial position l and the chord position SHOLE of the small hole 2, and determine the approximate value range of the aperture d, line surface angle α and direction angle β of the small hole 2 according to the blowing flow required to suppress the fan flow separation, and at the same time combine the mixing degree of the blowing airflow of the small hole 2 and the flow in the separation zone. Then, a detailed parameterized analysis is performed on the above parameters to explore the different effects of different parameter values on the fan flow field, and finally determine the specific values of the above five parameters, thereby completing the design of the small hole 2 array. For different types of fans, due to the different airflow flow mechanisms inside the flow channel, the size and array arrangement position of the small hole 2 will change. This design method can improve the PQ performance in the fan working area by 5%~10%, reduce the overall noise by 3~7dB, and reduce power consumption by 2%~5%, or even more.
[0038] The terms "upper", "lower", "outer side", "inner side" and the like (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish the relative relationship in position without giving qualitative description. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.
[0039] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A design method for a high-air-volume, low-noise fan blade, wherein the high-air-volume, low-noise fan blade comprises a blade body, wherein the blade body is formed by stacking blades with large turning angles, wherein the blade turning angle of the blade body is θ, wherein the value range of θ is 20 to 65 degrees, wherein the two fan surfaces on the blade body are respectively a suction surface and a pressure surface, wherein the curvatures of the suction surface and the pressure surface are different, wherein the starting position where fluid separation occurs on the suction surface is the separation starting point, wherein the separation starting point is located in the middle and rear part of the suction surface, wherein at least two rows of small holes are provided on the blade body, wherein the small holes are all located upstream of the separation starting point, and wherein the small holes penetrate the pressure surface and the suction surface, wherein the blade body is provided with at least two rows of small holes, wherein the small holes are all located upstream of the separation starting point, and wherein the small holes penetrate the pressure surface and the suction surface, wherein the blade body is provided with at least two rows of small holes, wherein the small holes are located upstream of the separation starting point, and wherein the small holes penetrate the pressure surface and the suction surface, wherein the blade body is provided with at least two rows of small holes, wherein the small holes penetrate the pressure surface and the suction surface, and wherein the blade body is provided with at least two rows of small holes, wherein the small holes are all located upstream of the separation starting point, and wherein the small holes penetrate the pressure surface and the suction surface, and wherein the blade body is provided with at least two rows of small holes, ... The design method of the fan blade includes the following steps: A1: Increase the blade turning angle; A2: Based on step A1, design an opening at the upstream position of the separation starting point; A3: Design the size and array layout of the small holes; A4: Determine the geometric position of each small hole on the fan blade body; A5: Determine the opening direction and the diameter of the small hole; Among them, according to the starting position and flow separation range of the flow separation at the suction surface of the fan, the approximate value range of the radial position and the chord position of the small hole is determined, and according to the blowing flow required to suppress the flow separation of the fan, and at the same time combined with the mixing degree of the blowing airflow of the small hole and the flow in the separation zone, the approximate value range of the aperture, line-surface angle and direction angle of the small hole is determined, and then the parameters of the above-mentioned small holes are subjected to detailed parametric analysis, and according to the different effects of different parameter values on the fan flow field, the specific values of the above-mentioned parameters are finally determined, thereby completing the design of the small hole array; wherein, the straight line b represents the straight line passing through point A in space and parallel to the fan rotation axis, point A is the center point of the hole outlet, and the plane where the straight line b is located and perpendicular to the radius corresponding to point A is selected as the reference plane S, and the angle between the axis k of the small hole and the reference plane S is defined as the line-surface angle α, and the angle between the projection k' of the axis of the small hole on the reference plane S and the straight line b is defined as the direction angle β, and the two angles are used to determine the blowing direction of the small hole.
2. The design method of a high air volume and low noise fan blade according to claim 1, characterized in that: During the design process, parameters are defined and parametric analysis is performed.
3. The design method of a high air volume and low noise fan blade according to claim 2, characterized in that: h represents the blade height of the fan blade, and the radial position l of the hole is determined by the relative blade height l / h; SSS represents the arc length of the suction surface blade from the leading edge to the trailing edge at the blade height where the center point of the hole outlet is located, and the chordal position SHOLE is determined by the relative arc length position SHOLE / SSS.
4. The method for designing a high air volume and low noise fan blade according to any one of claims 1 to 3, characterized in that: For different types of fans, the size and array arrangement of the small holes will change due to the different airflow mechanisms inside the flow channels.
5. The method for designing a high air volume and low noise fan blade according to claim 1, characterized in that: The fan blade body is provided with three rows of small holes, and each row includes a plurality of small holes arranged at intervals.