Optimized structure of suction surface of axial flow wind wheel
By adding a bird feather-like aerodynamic shape and a guide channel structure to the back pressure surface of the axial flow impeller, the noise and resonance problems were solved, the flow efficiency and fan performance were improved, and the blade life was extended.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- MITSUBISHI HEAVY IND HAIER QINGDAO AIR CONDITIONERS CO LTD
- Filing Date
- 2025-05-21
- Publication Date
- 2026-05-12
AI Technical Summary
现有轴流风轮在高速工况下产生宽频噪声、气流分离导致能量利用率降低及风轮与电机易产生同频共振，影响寿命。
在轴流风轮的背压面增加多层仿鸟类羽毛的非对称气动外形，设计定向涡流结构，通过导流槽梯度分布以引导气流形成有序纵向涡对，并优化叶片结构以提升整机强度，避免共振。
It effectively reduces noise by 1-3dB, improves flow efficiency by 1-3%, increases the working area of the blades, extends the life of the blades and reduces weight, avoids resonance, and improves the performance of the fan.
Smart Images
Figure CN224228946U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an optimized structure for the suction surface of an axial flow impeller, belonging to the field of fluid machinery technology. Background Technology
[0002] For example, the multi-channel axial flow focusing impeller disclosed in application number 201611237715.4 includes at least two layers of axial flow channels arranged sequentially around the axis of the multi-channel axial flow focusing impeller. The helical blades on the latter layer of axial flow channels are N times larger than those on the former layer of axial flow channels. Any helical blade on the former layer of axial flow channels corresponds to two helical blades on the latter layer of axial flow channels. The two corresponding helical blades are staggered, and the front edge of one helical blade is located on the same arc line as the front edge of the corresponding helical blade in the former layer, and the rear edge of the other helical blade is located on the same arc line as the rear edge of the corresponding helical blade in the former layer. This not only effectively increases the air outlet surface and heat dissipation area, but also gradually reduces the area of the blades in the secondary axial flow channels and gradually increases the shear line. The front and rear layers share the same blade line, resulting in a high impeller speed, effectively increasing wind speed and wind pressure, preventing wind interference between adjacent axial flow channels, and making the impeller easy to demold.
[0003] The above-mentioned applications still have shortcomings:
[0004] 1. Eddy current shedding generates broadband noise, which is particularly noticeable under high-speed conditions;
[0005] 2. Airflow separation reduces the actual working area of the blades, thus decreasing energy utilization.
[0006] 3. When the wind turbine and motor are running under rated conditions, they are prone to resonance due to their similar natural frequencies, which affects the life cycle of the wind turbine.
[0007] To address this issue, an optimized structure for the suction surface of an axial flow fan was designed. Utility Model Content
[0008] The main purpose of this invention is to provide an optimized structure for the suction surface of an axial flow fan.
[0009] The objective of this utility model can be achieved by adopting the following technical solution:
[0010] An optimized suction surface structure for an axial flow wind turbine, wherein the axial flow wind turbine is composed of an axial flow wind turbine and blades, with one side of the blades being a pressure surface;
[0011] On the other side of the blade, the first guide groove, the second guide groove and the third guide groove are distributed in a gradient structure from the inside to the outside;
[0012] The downward-sloping outer surface of the blade is the back pressure surface, and the blades are distributed around the outer ring of the hub.
[0013] Preferably, the first guide groove starts from the hub and ends at 0.35-0.45 of the outer diameter of the axial flow wind turbine.
[0014] Preferably, the second guide channel starts at the stop of the first guide channel and ends at 0.6-0.75 of the outer diameter of the axial flow impeller.
[0015] Preferably, the third guide channel starts at the stop of the second guide channel and ends at 0.9-0.95 of the outer diameter of the axial flow impeller.
[0016] Preferably, the pressure surface has at least one layer of staggered, feather-like aerodynamic shape.
[0017] Preferably, the blades on the axial flow wind turbine have an inclined structure.
[0018] The beneficial technical effects of this utility model are as follows:
[0019] This utility model provides an optimized suction surface structure for an axial flow wind turbine, consisting of a hub and two or more blades. The blades, viewed from the front, have a back pressure surface and a pressure surface. Work is primarily done on the pressure surface. Due to the higher flow velocity on the back pressure surface, radial flow is more easily generated, resulting in small radial... The flow generates noise and reduces flow efficiency. By adding a multi-layered asymmetric aerodynamic shape resembling bird feathers (such as the hooked edges of primary feathers and the gap structure of secondary feathers) to the back pressure surface of the axial flow impeller, directional vortices are generated. The structure of the feather edges guides the airflow to form ordered longitudinal vortex pairs (CVPs). CFD simulations show that the vortex intensity is increased by more than 20%.
[0020] Due to the different strengths of the three layers of different gradients on its back pressure surface, the blades of existing axial flow wind turbines are generally cantilever beams, and their first natural frequency can be estimated as: fn=12πKeffmefffn=2π1meffKeff
[0021] Keff is the equivalent stiffness (related to material and section moment of inertia II), and meff is the equivalent mass (related to blade length LL and mass distribution). By making the blade radial and spanwise directions into a multi-layered asymmetric aerodynamic shape resembling bird feathers as described above, the overall strength of the blade can be effectively improved. The natural frequency of its axial flow impeller can be effectively increased compared to existing solutions, thereby avoiding resonance with the natural frequency of the motor when running in conjunction with the motor, thus improving service life and reducing noise.
[0022] The specific structure is as follows: from a horizontal forward projection, the first layer of guide channels starts from the wind turbine hub and ends at 0.35-0.45 of the outer diameter of the axial wind turbine. It is used to suppress secondary flow outside the hub.
[0023] The second layer of guide channels starts at the stop of the first layer of guide channels and ends at 0.6-0.75 of the outer diameter of the axial flow impeller, matching the trend of boundary layer thickening;
[0024] The third-layer guide channel begins at the stop of the second-layer guide channel and terminates at 0.9-0.95 of the outer diameter of the axial flow impeller. It is specifically used for breaking down and dispersing gap vortices.
[0025] from Figure 3 From the top view, the three structures of the first-layer guide channel, the second-layer guide channel, and the third-layer guide channel are progressively layered. The concave dimension of the first-layer guide channel is 0.1-1 times that of the second-layer guide channel, the concave dimension of the second-layer guide channel is 0.1-1 times that of the third-layer guide channel, and the concave dimension of the third-layer guide channel is 0.01% to 50% of the thickness of the wind turbine blade.
[0026] The feather-like recesses and scale structure can reduce aerodynamic noise by 1-3 dB. The new design can improve the radial flow of the impeller, and the flow field optimization can increase the efficiency of the fan by 1% to 3%. The working area of the blades is increased. The spaced arrangement of the feather-like recesses and the asymmetrical hub design take into account both strength and lightweight requirements. At the same time, its natural frequency can effectively avoid the operating frequency of the motor and avoid resonance, thereby effectively improving the performance and life of the impeller. The new structure is conducive to weight reduction while ensuring strength, thus achieving cost reduction. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the back structure of a preferred embodiment of an axial flow impeller suction surface optimization structure according to the present invention;
[0028] Figure 2 This is a side view of a preferred embodiment of an optimized suction surface structure for an axial flow impeller according to the present invention;
[0029] Figure 3 This is a transverse front view of a preferred embodiment of an optimized suction surface structure for an axial flow fan according to the present invention.
[0030] In the diagram: 1. Axial flow impeller; 2. Pressure surface; 3. Back pressure surface; 4. Hub; 5. Blade; 6. First layer of guide channel; 7. Second layer of guide channel; 8. Third layer of guide channel. Detailed Implementation
[0031] To enable those skilled in the art to understand the technical solution of this utility model more clearly, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of this utility model is not limited thereto.
[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.
[0033] Therefore, the following detailed description of the embodiments of this utility model is not intended to limit the scope of the claimed utility model, but merely to illustrate some embodiments of the utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.
[0034] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.
[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0036] In the description of this utility model, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product is usually placed when in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are only for the convenience of describing this utility model and simplifying the description, and do not 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 utility model. In addition, the terms "first" and "second" are only used to distinguish the description and should not be construed as indicating or implying relative importance.
[0037] Example 1
[0038] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment proposes an optimized suction surface structure for an axial flow wind turbine, consisting of a hub 4 and two or more blades 5. The blades 5, viewed from the front, are divided into a back pressure surface 3 and a pressure surface 2. Work is primarily done on the pressure surface 2. Due to the higher flow velocity on the back pressure surface 3, radial flow is more easily generated, resulting in small radial... The flow generates noise and reduces flow efficiency. By adding a multi-layered asymmetric aerodynamic shape (such as the hooked edge of the primary feather and the gap structure of the secondary feather) to the back pressure surface 3 of the axial flow impeller 1, directional vortices are generated. The structure of the feather edge guides the airflow to form ordered longitudinal vortex pairs (CVPs). CFD simulation shows that the vortex intensity is increased by more than 20%.
[0039] Example 2
[0040] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment proposes an optimized structure for the suction surface of an axial flow wind turbine. Due to the different strengths of the three layers of specific structures with different gradients on its back pressure surface 3, the blades 5 of the existing axial flow wind turbine 1 are generally cantilever beams, and their first natural frequencies can be estimated as: fn = 1 / 2πKeffmefffn = 2π1meff, Keff.
[0041] Keff and Keff are equivalent stiffness (related to material and section moment of inertia II), and meff is equivalent mass (related to blade 5 length LL and mass distribution). By making the radial spanwise direction of blade 5 into a multi-layered asymmetric aerodynamic shape that resembles bird feathers as described above, the overall strength of blade 5 can be effectively improved. The natural frequency of its axial flow impeller 1 can be effectively improved compared with the existing scheme, thereby avoiding resonance with the natural frequency of the motor when running with it, thus improving service life and reducing noise.
[0042] The specific structure is as follows: from the horizontal forward projection, the first layer of guide channel 6 starts from the wind turbine hub 4 and ends at 0.35-0.45 of the outer diameter of the axial flow wind turbine 1. It is used to suppress the secondary flow outside the hub 4.
[0043] The second layer of guide channel 7 starts at the stop of the first layer of guide channel and ends at 0.6-0.75 of the outer diameter of the axial flow impeller 1, matching the boundary layer thickening trend;
[0044] The third-layer guide channel 8 starts at the stop of the second-layer guide channel 7 and ends at 0.9-0.95 of the outer diameter of the axial flow impeller 1. It is specifically used for breaking and dispersing gap vortices.
[0045] from Figure 3 From the top view, the three-layer structure of the first-layer guide channel 6, the second-layer guide channel 7, and the third-layer guide channel 8 is progressively layered. The concave dimension of the first-layer guide channel 7 is 0.1-1 times that of the second-layer guide channel 7, the concave dimension of the second-layer guide channel 7 is 0.1-1 times that of the third-layer guide channel 8, and the concave dimension of the third-layer guide channel is 0.01% to 50% of the thickness of the wind turbine blade.
[0046] The feather-like recesses and scale structure can reduce aerodynamic noise by 1-3 dB. The new design can improve the radial flow of the impeller, and the flow field optimization can increase the efficiency of the fan by 1% to 3%. The working area of the blades is increased. The spaced arrangement of the feather-like recesses and the asymmetric hub design take into account both strength and lightweight requirements. At the same time, its natural frequency can effectively avoid the operating frequency of the motor and avoid resonance, thereby effectively improving the performance and life of the impeller. The new structure is conducive to weight reduction while ensuring strength, thus achieving cost reduction.
[0047] The above description is only a further embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope disclosed by the present utility model, based on the technical solution and concept of the present utility model, shall fall within the protection scope of the present utility model.
Claims
1. An optimized structure for the suction surface of an axial flow wind turbine, characterized in that: The axial flow impeller (1) consists of an axial flow impeller (1) and blades (5), with one side of the blades (5) being a pressure surface (2); On the other side of the blade (5), a first guide groove (6), a second guide groove (7) and a third guide groove (8) are distributed in a gradient structure from the inside to the outside; The outer side of the blade (5) is inclined downward as the back pressure surface (3), and the blade (5) is distributed around the outer ring of the hub (4).
2. The optimized suction surface structure of an axial flow wind turbine according to claim 1, characterized in that: The first guide groove (6) starts from the hub (4) and ends at 0.35-0.45 of the outer diameter of the axial flow fan (1).
3. The optimized suction surface structure of an axial flow wind turbine according to claim 1, characterized in that: The second guide channel (7) starts at the stop of the first guide channel (6) and ends at 0.6-0.75 of the outer diameter of the axial flow impeller (1).
4. The optimized suction surface structure of an axial flow wind turbine according to claim 2, characterized in that: The third guide channel (8) starts at the stop of the second guide channel (7) and ends at 0.9-0.95 of the outer diameter of the axial flow impeller (1).
5. The optimized suction surface structure of an axial flow wind turbine according to claim 3, characterized in that: The pressure surface (2) has at least one layer of staggered feather-like aerodynamic shape.
6. The optimized suction surface structure of an axial flow wind turbine according to claim 2, characterized in that: The blades (5) on the axial flow wind turbine (1) are inclined.