Axial flow fan assembly comprising detachable bionic sawtooth rear guide vane

Abstract

The invention discloses an axial flow fan assembly comprising detachable bionic sawtooth rear guide vanes. The axial flow fan assembly comprises a motor, an impeller, a motor support, an air guide ring body and a plurality of independently-formed rear guide vane modules. The rear guide vane modules are distributed in the circumferential direction of the air guide ring body in an array mode, and each rear guide vane module is a non-bearing piece and detachably fixed to the air guide ring body through an expansion type locking mechanism. The front edge of the rear guide vane module is provided with a bionic sawtooth structure, and the bionic sawtooth structure is composed of convex teeth and concave teeth which are continuously arranged in the spanwise direction and used for rectifying rotating airflow exhausted by the impeller and restraining aerodynamic noise. Functional separation of a pneumatic component and a bearing component is achieved, a design space is provided for pneumatic optimization of the rear guide vane, modular design is convenient to assemble and maintain, and aerodynamic noise is effectively reduced through the bionic sawtooth structure.

Description

Technical Field

[0001] This invention relates to the field of fan aerodynamics and structural design, and specifically to an axial flow fan assembly including detachable biomimetic serrated rear guide vanes. Background Technology

[0002] Axial flow fans are widely used in ventilation, heat dissipation, dust removal, and air conditioning applications. To improve the fan's pressure rise capacity and efficiency, and reduce aerodynamic noise, guide vanes are often installed downstream of the impeller in engineering applications. These guide vanes rectify and diffuse the rotating airflow with tangential components discharged from the impeller, converting some kinetic energy into static pressure energy, thereby improving the fan's static pressure characteristics and adaptability to various operating conditions.

[0003] In existing axial flow fan structural designs, to simplify assembly processes, reduce the number of parts, and lower procurement and management costs, the industry commonly adopts an integrated solution of "guide ring + rear guide vane + bracket," especially in plastic parts applications where injection molding is often used to combine the guide ring, rear guide vane, and motor bracket into a single integral structure. This type of solution has certain advantages in terms of initial assembly efficiency and the number of parts. However, because it forcibly couples the original aerodynamic components (rear guide vane) with the load-bearing components (bracket), it can easily lead to problems such as structural safety issues, limited aerodynamic optimization, poor adaptability to operating conditions, and increased life-cycle costs. Specifically: I. Structural safety: In the integrated design, the weight of the motor is transmitted through areas such as the root of the rear guide vane. To meet aerodynamic requirements, the rear guide vane is usually thin and airfoil-shaped, making it difficult to balance load-bearing stiffness and fatigue life. Under long-term vibration and start-stop loads, stress concentration and fatigue cracks are likely to occur at geometric abrupt changes, posing a risk of failure such as root fracture leading to motor displacement and impeller rubbing.

[0004] II. In terms of aerodynamic performance: The rear guide vane requires a high degree of design freedom to match different impeller outlet flow angles and optimize noise reduction. However, the integrated load-bearing constraints will force the rear guide vane to be thickened, reinforced, or have a solidified profile and installation angle, making it difficult to implement or maintain the reliability of biomimetic noise reduction structures such as sawtooth, thus limiting efficiency improvement and noise control.

[0005] III. In terms of operating condition adaptation and maintenance: Different application scenarios have different requirements for air volume / pressure, impeller diameter, number of blades and speed. The rear guide vane needs to be matched with parameters such as profile, angle and chord length accordingly. The integrated structure makes it difficult to replace the rear guide vane separately, which means that adaptation and upgrades require the whole system to be redone, resulting in long maintenance downtime, large material waste and high operation and maintenance costs.

[0006] Therefore, there is an urgent need for a wind turbine rear guide vane structure that can improve the aerodynamic optimization space of the rear guide vane, reduce assembly and maintenance costs, and improve noise and efficiency performance without sacrificing structural reliability. Summary of the Invention

[0007] This invention provides a combined independent rear guide vane fan assembly with a biomimetic serrated leading edge to solve the technical problems of insufficient structural reliability, limited aerodynamic optimization, and high operating condition adaptability and maintenance costs caused by the coupling of aerodynamic components and load-bearing components in the existing integrated structure of air guide ring, rear guide vane and support.

[0008] This invention adopts the following technical solution: an axial flow fan assembly including detachable biomimetic serrated rear guide vanes, comprising a motor, an impeller, and a motor bracket, wherein the motor is fixed on the motor bracket, and the impeller is poweredly connected to the motor to achieve airflow delivery, characterized in that: The fan assembly also includes the air guide ring body; and several independently formed rear guide vane modules, which are arranged in an array along the circumference of the air guide ring body; The rear guide vane module is constructed as a non-load-bearing component. The rear guide vane module includes blades that extend radially. The blades are three-dimensional twisted curved surfaces and are detachably fixed to the air guide ring body by an expansion locking mechanism to match the spiral flow field at the upstream impeller outlet and to achieve deswirl and diffusion of the rotating airflow containing tangential components in the blade channel. The leading edge of the rear guide vane module has at least a portion of a biomimetic sawtooth structure. The biomimetic sawtooth structure consists of several convex and concave teeth arranged continuously along the span. The rear guide vane module, the expansion locking mechanism, and the biomimetic sawtooth structure work together to achieve rectification, noise reduction, and vibration isolation of the rotating airflow.

[0009] Furthermore, the expansion locking mechanism includes a hollow mounting post integrally formed on one side of the root of the rear guide vane module, and a mounting hole integrally formed on the other side of the root of the rear guide vane module and adapted to the hollow mounting post; and a separate locking element. The hollow mounting post has at least two radially expandable elastic bifurcations at its end; the locking element is adapted to be installed inside the hollow mounting post, and when the locking element is inserted axially, it forces the elastic bifurcations to expand radially, thereby forming an interference lock fit with the inner wall of the mounting hole.

[0010] Furthermore, a locking part is provided on one side of the elastic bifurcation part. After the hollow mounting post is locked with the mounting hole, the locking part abuts against the edge of the mounting hole.

[0011] Furthermore, the expansion locking mechanism also integrates an angle limiting structure, which includes: a positioning boss protruding from one side of the connecting surface at the root of the rear guide vane module, and a positioning groove recessed on the other side of the mating surface at the root of the rear guide vane module; the positioning boss and the positioning groove cooperate to limit the installation angle between two adjacent rear guide vane modules.

[0012] Furthermore, the outline of the biomimetic sawtooth structure is defined by a trigonometric function curve, satisfying the following geometric parameters: tooth height B is 3mm to 10mm; tooth pitch A is 10mm to 50mm; the biomimetic sawtooth structure covers 30% to 95% of the total length of the leading edge and extends from the inside to the outside of the rear guide vane module to cover the tip region with high airflow velocity; the rear guide vane module is injection molded from glass fiber reinforced engineering plastic, with a blade body thickness of 3mm to 8mm, and a lightweight hollow structure is provided on the non-aerodynamic working surface of the blade sidewall, with reinforcing ribs at the edge of the hollow structure to maintain rigidity.

[0013] Furthermore, the rear guide vane module also includes a sidewall diffuser section, which is located at the sidewall connection of the rear guide vane module. Its cross-sectional area gradually increases along the flow direction of the airflow to help convert the kinetic energy of the airflow into static pressure energy. A rear guide vane fixing foot is provided on one side of the sidewall diffuser section.

[0014] Furthermore, the fan assembly also includes a fan panel, a motor bracket directly connected to the fan panel or external structure to support the weight of the motor, a mesh cover on one side of the impeller, and a rear guide vane module that is spatially independent of the motor bracket and has a physical clearance groove to prevent motor vibration from being directly transmitted to the rear guide vane module.

[0015] Furthermore, the blade cross-section of the rear guide vane module is airfoil-shaped at different radial positions, and the blade cross-section installation angle and chord length change continuously along the radial direction. Specifically, at the first radial position, the installation angle is 50° to 60° and the chord length is 70mm to 80mm, while at the second radial position, the installation angle is 60° to 70° and the chord length is 70mm to 80mm. The first radial position is smaller than the second radial position, thereby making the blade as a whole have a three-dimensional spatial twisted curved surface shape to match the spiral flow field at the upstream impeller outlet, and maintaining a smooth transition of installation angle and chord length at the intermediate radial position between the first and second radial positions.

[0016] Among them, at a diameter of ∅433mm, the installation angle is 46° to 66° and the chord length is 46mm to 106mm; At a diameter of ∅523mm, the installation angle is 50° to 70° and the chord length is 46mm to 106mm; At a diameter of ∅610mm, the installation angle is 43° to 63° and the chord length is 45mm to 105mm; At a diameter of ∅698mm, the installation angle is 55° to 75° and the chord length is 43mm to 103mm; At a diameter of ∅785mm, the installation angle is 51° to 71° and the chord length is 43mm to 103mm; At a diameter of ∅873mm, the installation angle is 51° to 71° and the chord length is 46mm to 106mm; At a diameter of ∅960mm, the installation angle is 47° to 67° and the chord length is 50mm to 110mm.

[0017] By specifying the range of the mounting angle and chord length at multiple diameter locations and employing a smooth transition between adjacent sections, the blade as a whole forms a three-dimensional spatial twisted surface shape to match the helical flow field at the upstream impeller outlet.

[0018] Furthermore, the rear guide vane module is also equipped with an annular damping and reinforcement structure. The damping and reinforcement structure is manifested as an integrated reinforcing rib surrounding the main body of the rear guide vane, which is used to disperse aerodynamic loads and improve the overall structural rigidity, while suppressing the transmission of high-frequency vibrations on the guide vane surface.

[0019] Furthermore, the rear guide vane module has a shrinkage reduction structure in the area of ​​uneven wall thickness. By reducing the local wall thickness and setting a transition rounded corner, the wall thickness of the area of ​​uneven wall thickness is made to be consistent with the wall thickness of the surrounding main body, so as to eliminate the surface shrinkage defects caused by uneven cooling shrinkage during injection molding.

[0020] The beneficial effects of this invention are as follows: I. This invention separates the aerodynamic components from the load-bearing components by setting the rear guide vane module to be independently formed and constructed as a non-load-bearing component. The motor bracket bears the weight of the motor, while the rear guide vane module only undertakes the function of airflow rectification. This allows the design of the rear guide vane profile to be free from load constraints, providing greater design space for aerodynamic parameter optimization, while also enabling the blade to be made thinner and more airfoil-shaped.

[0021] II. This invention sets a biomimetic sawtooth structure on the leading edge of the rear guide vane module. The irregular edge formed by the alternating distribution of convex and concave teeth interferes with the rotating airflow, decomposes the large-scale vortex structure into a small-scale vortex structure, reduces the intensity of turbulent pulsation, and can effectively suppress the aerodynamic noise generated by the interaction between the airflow and the blade surface and improve the sound quality of the fan during operation.

[0022] Third, by setting an expansion locking mechanism and an angle limiting structure, the present invention utilizes the radial expansion of the elastic bifurcation to form an interference lock fit, and the convex-concave engagement of the positioning boss and the positioning groove to limit the installation angle, thereby achieving the technical effect of detachable connection of the rear guide vane module and automatic positioning of the assembly angle, reducing the assembly difficulty and facilitating maintenance and replacement.

[0023] Fourth, by setting up a physical clearance groove, the present invention makes the rear guide vane module and the motor support spatially independent, cuts off the transmission path of motor vibration to the rear guide vane module, achieves the technical effect of vibration isolation between the rear guide vane module and the motor support, reduces the generation of structural noise and extends the fatigue life of the rear guide vane module.

[0024] V. This invention, by setting up a shock-absorbing and reinforcing structure and a shrinkage-reducing structure, utilizes annular reinforcing ribs to disperse aerodynamic loads and improve structural rigidity. At the same time, it achieves the effect of suppressing high-frequency vibration transmission and eliminating shrinkage defects on the injection molding surface through local thinning, while ensuring the structural reliability and appearance quality of the product. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present invention, and are not intended to limit the present invention.

[0026] Figure 1 This is a schematic diagram of the overall structure of the wind turbine assembly; Figure 2 Left view of the wind turbine assembly; Figure 3 This is a schematic diagram of the overall structure after the rear guide vane module is assembled. Figure 4 This is a schematic diagram of the assembly of the rear guide vane module; Figure 5 This is a schematic diagram of the rear guide vane module; Figure 6 This is a schematic diagram of the expansion locking mechanism; Figure 7 Assembly drawing of expansion locking mechanism and angle limiting structure; Figure 8 A schematic diagram of the expansion locking mechanism when locked; Figure 9 This is an intersection diagram at different diameters of the rear guide vane module; Figure 10 The following are cross-sectional views of the rear guide vane module at different diameters. Figure 11 To compare the flow field with and without a guide vane; Figure 12 This is a schematic diagram showing the overall performance comparison curves of the wind turbine; Figure 13 This is a schematic diagram of the parameters used for measuring convex and concave teeth.

[0027] Explanation of reference numerals in the attached figures: 10. Motor; 11. Impeller; 12. Motor bracket; 13. Mesh cover; 14. Fan panel; 20. Air guide ring body; 30. Rear guide vane module; 31. Lightweight hollow structure; 32. Reinforcing rib; 33. Side wall diffuser section; 34. Physical clearance groove; 35. Rear guide vane fixing foot; 40. Expansion locking mechanism; 41. Hollow mounting post; 41a. Elastic fork; 41b. Locking part; 42. Mounting hole; 43. Locking element; 50. Bionic sawtooth structure; 51. Convex teeth; 52. Concave teeth; 60. Angle limiting structure; 61. Positioning boss; 62. Positioning groove; 70. Vibration-damping and reinforced structure; 80. Shrinkage-thinning structure. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example 1

[0029] This application discloses an axial flow fan assembly including a detachable biomimetic serrated rear guide vane, with reference to... Figures 1 to 6 The fan assembly includes a motor 10, an impeller 11, a motor bracket 12, a guide vane body 20, and several independently formed rear guide vane modules 30. The motor 10 is fixedly mounted on the motor bracket 12, and the impeller 11 is poweredly connected to the motor 10, achieving axial airflow delivery under the drive of the motor 10. The guide vane body 20 forms the outer peripheral contour structure of the fan assembly, and several rear guide vane modules 30 are arranged in an array along the circumference of the guide vane body 20. Each rear guide vane module 30 is constructed as a non-load-bearing component and is detachably fixed to the guide vane body 20 by an expansion locking mechanism 40.

[0030] In this technical solution, the aerodynamic and load-bearing components are functionally separated by adopting an independently formed, non-load-bearing structure for the rear guide vane module 30. The motor bracket 12 directly bears the weight of the motor 10, while the rear guide vane module 30 only undertakes the aerodynamic functions of airflow rectification and noise reduction. The two are independent of each other in terms of structural stress paths. This functional separation design allows the profile design of the rear guide vane module 30 to focus on optimizing aerodynamic performance without considering the structural constraints imposed by bearing the weight of the motor, thus providing greater design flexibility for adjusting the aerodynamic parameters of the rear guide vane. Furthermore, since the rear guide vane module 30 does not participate in the transmission of motor weight, its structure can be made thinner and more airfoil-shaped, which helps reduce aerodynamic drag and improve rectification efficiency.

[0031] Reference Figure 5 and Figure 13The leading edge of the rear guide vane module 30 is provided with a biomimetic sawtooth structure 50 in at least a portion of its leading edge. This biomimetic sawtooth structure 50 consists of a plurality of convex teeth 51 and concave teeth 52 arranged continuously along the spanwise direction. In this technical solution, by setting the biomimetic sawtooth structure 50 at the leading edge of the rear guide vane module 30, the geometric features of the sawtooth structure are used to interfere with and decompose the rotating airflow discharged from the impeller 11. When the rotating airflow containing a tangential component reaches the leading edge of the rear guide vane module 30, the irregular edge formed by the alternating distribution of convex teeth 51 and concave teeth 52 in the biomimetic sawtooth structure 50 can change the local flow state of the airflow, decomposing large-scale vortex structures into small-scale vortex structures, thereby reducing the intensity of turbulent pulsation. This vortex structure decomposition process can effectively suppress the aerodynamic noise generated by the interaction between the airflow and the blade surface, achieving a low-noise effect during wind turbine operation.

[0032] Reference Figures 6 to 8 The expansion locking mechanism 40 includes a hollow mounting post 41 integrally formed on one side of the root of the rear guide vane module 30, and a mounting hole 42 integrally formed on the other side of the root of the rear guide vane module 30 and adapted to the hollow mounting post 41. It also includes a separate locking member 43. The end of the hollow mounting post 41 has at least two radially expandable elastic forks 41a, and the locking member 43 is adapted to be installed inside the hollow mounting post 41. When the locking member 43 is axially inserted into the hollow mounting post 41, the outer wall of the locking member 43 generates a radial thrust on the inner wall of the elastic forks 41a, forcing the elastic forks 41a to expand radially outward. The expanded elastic forks 41a form an interference fit with the inner wall of the mounting hole 42, thereby locking two adjacent rear guide vane modules 30 together.

[0033] In this technical solution, a detachable connection between the rear guide vane modules 30 is achieved by setting an expansion-type locking mechanism 40. The working principle of the expansion-type locking mechanism 40 is based on the radial deformation characteristics of the elastic bifurcation portion 41a. Before the locking member 43 is inserted, the elastic bifurcation portion 41a is in a naturally contracted state, and its outer diameter is smaller than the inner diameter of the mounting hole 42, which facilitates the insertion of the hollow mounting post 41 into the mounting hole 42 for positioning. After the locking member 43 is inserted, the elastic bifurcation portion 41a is expanded and forms a radial interference fit with the inner wall of the mounting hole 42, providing constraints on axial pull-out force and circumferential torsional force. This locking method does not require the use of additional fasteners or tools, and the assembly process is simple and quick, suitable for applications requiring rapid on-site assembly and maintenance replacement. At the same time, when disassembly is required, the elastic bifurcation portion 41a can be returned to its contracted state by pulling out the locking member 43, releasing the interference fit with the mounting hole 42, thereby achieving non-destructive disassembly and reuse of the rear guide vane module 30.

[0034] A locking part 41b is also provided on one side of the elastic bifurcation 41a. After the hollow mounting post 41 and the mounting hole 42 complete the locking engagement, the locking part 41b forms a pressing contact with the edge of the mounting hole 42. In this technical solution, the locking part 41b provides axial positioning for the expansion locking mechanism 40. The locking part 41b plays a limiting role during the insertion of the hollow mounting post 41 into the mounting hole 42. When the locking part 41b contacts the edge of the mounting hole 42, it indicates that the hollow mounting post 41 has been inserted to the predetermined depth, ensuring that the engagement area between the elastic bifurcation 41a and the mounting hole 42 is in the optimal position. At the same time, the pressing contact between the locking part 41b and the edge of the mounting hole 42 increases the axial constraint after locking, reduces the possibility of axial loosening or displacement of the rear guide vane module 30 under aerodynamic load, and improves the stability and reliability of the connection.

[0035] Reference Figure 7 The expansion locking mechanism 40 also integrates an angle limiting structure 60. This angle limiting structure 60 includes a positioning boss 61 protruding from one side of the connecting surface at the root of the rear guide vane module 30, and a positioning groove 62 recessed into the mating surface at the other side of the root of the rear guide vane module 30. The positioning boss 61 and the positioning groove 62 cooperate to limit the installation angle between two adjacent rear guide vane modules 30. The angle positioning of the rear guide vane modules 30 during assembly is achieved by setting the angle limiting structure 60. The engagement of the positioning boss 61 and the positioning groove 62 is a convex-concave meshing type. When adjacent rear guide vane modules 30 are assembled, the positioning boss 61 of one rear guide vane module 30 inserts into the positioning groove 62 of another rear guide vane module 30, and the mating surfaces of the two form a circumferential limit, thereby determining the relative installation angle between the two rear guide vane modules 30. This angle limiting mechanism eliminates the reliance on angle measuring tools or positioning fixtures during assembly, allowing operators to accurately position the angle through simple alignment and insertion, reducing assembly difficulty and improving assembly consistency.

[0036] Reference Figure 1 and Figure 2The fan assembly also includes a fan panel 14, and a motor bracket 12 is directly connected to the fan panel 14 or an external structure to support the weight of the motor 10. A mesh cover 13 is provided on one side of the impeller 11 to prevent foreign objects from entering the rotation area of ​​the impeller 11. The rear guide vane module 30 is spatially independent of the motor bracket 12 and is provided with a physical clearance groove 34 to prevent vibrations generated by the motor 10 during operation from being directly transmitted to the rear guide vane module 30. In this technical solution, vibration isolation between the rear guide vane module 30 and the motor bracket 12 is achieved by providing a physical clearance groove 34 on the rear guide vane module 30. The physical clearance groove 34 creates a certain spatial gap between the rear guide vane module 30 and the motor bracket 12, preventing direct structural contact. The mechanical vibrations generated by the motor 10 during operation are transmitted through the motor bracket 12. Due to the presence of the physical clearance groove 34, these vibrations cannot be directly transmitted to the rear guide vane module 30, thereby reducing structural noise generated by forced vibration in the rear guide vane module 30. In addition, the vibration isolation design also helps to extend the fatigue life of the rear guide vane module 30 and avoid cracks in the stress concentration area due to long-term vibration load.

[0037] Reference Figure 9 and Figure 10 The blade section installation angle of the rear guide vane module 30 exhibits a three-dimensional twisted shape as the radius changes, wherein: The blade cross-section of the rear guide vane module 30 is airfoil-shaped at different radial positions, and the blade cross-section installation angle and chord length change continuously radially. The first radius is located on the inner side of the rear guide vane module 30, near the hub region; the second radius is located on the outer side of the rear guide vane module 30, near the blade tip region. At the first radial position, the installation angle is 50° to 60° and the chord length is 70mm to 80mm; at the second radial position, the installation angle is 60° to 70° and the chord length is 70mm to 80mm. The first radial position is smaller than the second radial position, thus giving the blade an overall three-dimensional twisted surface shape to match the helical flow field at the upstream impeller outlet, and maintaining a smooth transition in installation angle and chord length at the intermediate radial position between the first and second radial positions.

[0038] As an optional implementation of this embodiment, in the rear guide vane module 30, the data acquisition values ​​of the rear guide vane are selected from the following ranges: at a diameter of ∅433mm, the installation angle is 46° to 66° and the chord length is 46mm to 106mm; at a diameter of ∅523mm, the installation angle is 50° to 70° and the chord length is 46mm to 106mm; at a diameter of ∅610mm, the installation angle is 43° to 63° and the chord length is 45mm to 1... 0.5mm; at a diameter of ∅698mm, the installation angle is 55° to 75° and the chord length is 43mm to 103mm; at a diameter of ∅785mm, the installation angle is 51° to 71° and the chord length is 43mm to 103mm; at a diameter of ∅873mm, the installation angle is 51° to 71° and the chord length is 46mm to 106mm; at a diameter of ∅960mm, the installation angle is 47° to 67° and the chord length is 50mm to 110mm.

[0039] As the most preferred implementation method in this embodiment: The cross section at ∅433 is airfoil-shaped with an installation angle of 56 degrees and a chord length of 76 mm. The cross-section at ∅523 is airfoil-shaped with an installation angle of 60 degrees and a chord length of 76 mm. The cross-section at ∅610 is airfoil-shaped, with an installation angle of 53 degrees and a chord length of 75 mm. The cross-section at ∅698 is airfoil-shaped with an installation angle of 65 degrees and a chord length of 73 mm. The cross-section at ∅785 is airfoil-shaped, with an installation angle of 61 degrees and a chord length of 73 mm. The cross-section at ∅873 is airfoil-shaped with an installation angle of 61 degrees and a chord length of 76 mm. The cross-section at ∅960 is airfoil-shaped, with an installation angle of 57 degrees and a chord length of 80 mm.

[0040] By making the installation angle of the blade section of the rear guide vane module 30 gradually vary with the radius, the profile of the rear guide vane can match the helical flow field at the outlet of the upstream impeller 11. During rotation, the impeller 11 applies a tangential velocity component to the airflow. Due to the different linear velocities of the impeller 11's radial sections, the ratio of the tangential velocity to the axial velocity of the exhaust airflow is also non-uniformly distributed radially, resulting in a radial variation in the airflow angle. The rear guide vane module 30 adopts a three-dimensional twisted shape, ensuring that its installation angle at different radii matches the corresponding incoming flow angle. This more effectively rectifyes the rotating airflow and converts tangential kinetic energy into axial static pressure, thereby improving the fan's static pressure efficiency and operational adaptability. The rear guide vane module 30 also features an annular damping and reinforcing structure 70, which is an integrated reinforcing rib 32 surrounding the main body of the rear guide vane. In this technical solution, the damping and reinforcing structure 70 disperses aerodynamic loads and enhances the overall structural stiffness of the rear guide vane module 30. The damping and reinforcing structure 70 is annularly distributed and integrally formed with the main body of the rear guide vane, creating a continuous reinforcing ring. Under aerodynamic loads, the blade surface of the rear guide vane module 30 experiences periodic pressure fluctuations. These loads are dispersed circumferentially through the damping and reinforcing structure 70, preventing load concentration in local areas. Simultaneously, the reinforcing rib form of the damping and reinforcing structure 70 increases the bending and torsional stiffness of the rear guide vane module 30, raising the structure's natural frequency and allowing it to avoid the operating frequencies of the motor 10 and impeller 11, thereby reducing resonance. Furthermore, the damping and reinforcing structure 70 suppresses the transmission of high-frequency vibrations on the guide vane surface, helping to reduce the radiated noise generated by the rear guide vane module 30 under high-frequency vibration excitation. Example 2

[0041] Based on Embodiment 1, this embodiment further explains the geometric parameters of the biomimetic sawtooth structure 50 and the materials and structure of the rear guide vane module 30. (Refer to...) Figure 5 and Figure 13 The outline of the biomimetic sawtooth structure 50 is defined by a trigonometric function curve, which satisfies the following geometric parameters: tooth height B is 3 mm to 10 mm; tooth pitch A is 10 mm to 50 mm. The biomimetic sawtooth structure 50 covers 30% to 95% of the total length of the leading edge and extends from the inside to the outside of the rear guide vane module 30 to cover the tip region with high airflow velocity.

[0042] In this technical solution, a smooth and continuous sawtooth edge morphology is obtained by defining the contour line of the biomimetic sawtooth structure 50 using trigonometric function curves. Compared with the sawtooth structure formed by splicing straight segments, the sawtooth defined by trigonometric function curves has a continuous curvature change in the transition area between the convex teeth 51 and the concave teeth 52, avoiding sharp geometric abrupt changes. This smooth transition geometric feature helps to reduce the flow separation intensity when the airflow passes through the sawtooth edge, and at the same time reduces the demolding difficulty and surface defect risk caused by stress concentration during injection molding.

[0043] The tooth height B is set within the range of 3mm to 10mm based on a comprehensive consideration of the chord length of the rear guide vane module 30 and the operating Reynolds number. If the tooth height B is too small, the serrated structure's interference with the airflow is insufficient, resulting in limited noise reduction; if the tooth height B is too large, the serrated structure itself becomes a source of aerodynamic drag, increasing the fan's energy loss. Within the tooth height range of 3mm to 10mm, the biomimetic serrated structure 50 can effectively suppress aerodynamic noise without significantly increasing aerodynamic drag. The tooth pitch A is set within the range of 10mm to 50mm based on the matching relationship between the characteristic scale of the incoming turbulence and the chord length of the blade. The tooth pitch A affects the serrated structure's ability to decompose vortex structures. Within the tooth pitch range of 10mm to 50mm, the serrated structure can effectively interfere with the main turbulent vortex structures in the incoming flow, achieving vortex scale decomposition and energy dissipation.

[0044] The biomimetic sawtooth structure 50 covers 30% to 95% of the total leading edge length. This coverage range takes into account the radial distribution characteristics of aerodynamic noise. In axial flow fans, the airflow velocity in the blade tip region is higher than that in the hub region, and aerodynamic noise generation is mainly concentrated in the high-speed airflow area on the blade tip side. By extending the biomimetic sawtooth structure 50 from the inside to the outside of the rear guide vane module 30 to cover the high-velocity blade tip region, targeted noise reduction treatment can be implemented in areas that contribute significantly to noise, improving the effectiveness of noise reduction measures. The lower limit of 30% coverage ensures that the sawtooth structure can cover the main noise-generating areas; the upper limit of 95% coverage provides necessary design margins for the structural integrity of the leading edge and manufacturing processes.

[0045] The aft guide vane module 30 is injection molded from glass fiber reinforced engineering plastic, with a blade body thickness ranging from 3mm to 8mm. By selecting glass fiber reinforced engineering plastic as the molding material for the aft guide vane module 30, the requirements for structural strength, molding process, and cost control are balanced. Glass fiber reinforced engineering plastic has a high elastic modulus and fatigue resistance, and its stiffness is between that of pure plastic and metal, meeting the stiffness requirements of the aft guide vane module 30 under aerodynamic loads. Simultaneously, glass fiber reinforced engineering plastic is suitable for injection molding, enabling the one-time molding of complex three-dimensional twisted blade profiles and biomimetic sawtooth structures, resulting in high production efficiency and controllable molding precision. Furthermore, to balance structural stiffness and aerodynamic performance, the blade body thickness is set to 3mm to 8mm: if the blade thickness is too small, the blade deflection under aerodynamic loads will be excessive, affecting the rectification effect; if the thickness is too large, the streamline profile of the blade will decrease, increasing the form drag of the airflow.

[0046] Reference Figure 5The rear guide vane module 30 has a lightweight perforated structure 31 on the non-aerodynamic working surface of the blade sidewall. Reinforcing ribs 32 are provided at the edges of the perforated structure 31 to maintain rigidity. In this technical solution, the weight reduction of the rear guide vane module 30 is optimized by setting a lightweight perforated structure 31 on the non-aerodynamic working surface. The non-aerodynamic working surface refers to the area on the sidewall of the rear guide vane module 30 that does not directly contact the airflow or has a minimal impact on airflow. Setting the perforated structure 31 in these areas can reduce material usage and lower the overall mass of the rear guide vane module 30 without affecting aerodynamic performance. The reduced mass of the rear guide vane module 30 helps to reduce the total weight of the wind turbine components and also reduces the inertial response of the rear guide vane module 30 under vibration excitation. The reinforcing ribs 32 at the edges of the perforated structure 31 are distributed around the perimeter of the perforations, forming a frame-like reinforcing network. This allows the material around the perforated area to bear the load originally borne by the perforated area, maintaining the overall rigidity and strength of the rear guide vane module 30 without significant decrease.

[0047] The rear guide vane module 30 also includes a sidewall diffuser section 33, located at the sidewall connection of the rear guide vane module 30, whose cross-sectional area gradually increases along the flow direction of the airflow. A rear guide vane fixing foot 35 is provided on one side of the sidewall diffuser section 33. In this technical solution, the sidewall diffuser section 33 assists in converting the kinetic energy of the airflow into static pressure energy. The cross-sectional area of ​​the sidewall diffuser section 33 gradually expands along the flow direction, forming a gradually expanding flow channel. According to the continuity equation and Bernoulli's equation in fluid mechanics, when the airflow passes through the gradually expanding flow channel, the velocity decreases while the pressure increases, realizing the conversion of kinetic energy into static pressure energy. This diffusion process enhances the static pressure recovery capability of the rear guide vane and improves the static pressure efficiency of the fan. The rear guide vane fixing foot 35 provides an interface for the rear guide vane module 30 to connect with the guide ring body 20 or other fixed structures, achieving reliable fixation and positioning of the rear guide vane module 30.

[0048] The rear guide vane module 30 has a shrinkage reduction structure 80 in the area of ​​uneven wall thickness. The shrinkage reduction structure 80 reduces the local wall thickness and sets a transition fillet to make the wall thickness of the uneven wall thickness area more consistent with the wall thickness of the surrounding main body, so as to eliminate surface shrinkage defects caused by uneven cooling shrinkage during injection molding.

[0049] In this technical solution, a shrinkage reduction structure 80 is used to address surface quality issues during injection molding. During injection molding, the molten plastic shrinks as it cools and solidifies within the mold cavity. When there is significant unevenness in the wall thickness of the part, the cooling rate of the thick-walled area is slower than that of the thin-walled area, causing the thick-walled area to shrink inward during cooling, forming surface depressions, i.e., shrinkage marks. The shrinkage reduction structure 80 locally thins the thick-walled area, making its wall thickness closer to that of the surrounding main body, thus achieving wall thickness uniformity. This makes the cooling shrinkage rate of each area more consistent, eliminating surface shrinkage marks caused by uneven shrinkage. The use of transition fillets ensures a smooth wall thickness change between the thinned area and the main body area, avoiding stress concentration points and ensuring structural integrity and a smooth appearance. Example 3

[0050] Based on Embodiments 1 and 2, this embodiment further explains the overall structural layout of the wind turbine assembly and the collaborative working relationship between the components. (Refer to...) Figures 1 to 4 as well as Figure 11 and Figure 12 , specifically: The motor 10, serving as the power source for the fan assembly, is fixedly mounted on the fan panel 14 via the motor bracket 12. The motor bracket 12 bears the entire weight of the motor 10, and its structural design meets the requirements for load-bearing rigidity and fatigue strength. The impeller 11 is mounted on the output shaft of the motor 10 and rotates under the drive of the motor 10, performing work on the airflow to achieve energy transfer. The guide ring body 20 is arranged around the outer periphery of the impeller 11, forming the outer boundary of the airflow channel, and also serves as the mounting base for the rear guide vane module 30. Several rear guide vane modules 30 are evenly distributed along the circumference of the guide ring body 20, together forming a complete annular array of rear guide vanes. The mesh cover 13 is located on the air inlet side of the impeller 11 to prevent foreign objects from entering the rotation area of ​​the impeller 11, protecting the operational safety of the impeller 11 and the motor 10.

[0051] Motor 10 drives impeller 11 to rotate. The blades of impeller 11 exert a force on the incoming airflow, causing the airflow to acquire axial and tangential velocity components, forming a spiral flow field containing a rotational component. The rotating airflow discharged from impeller 11 enters the region where the rear guide vane module 30 is located. The blade profile of the rear guide vane module 30 guides the airflow to change its flow direction, converting the tangential velocity component into an axial velocity component, thus rectifying the airflow. During the rectification process, the tangential kinetic energy of the airflow is converted into static pressure energy, increasing the static pressure at the fan outlet. (Refer to...) Figure 11 The flow field comparison diagrams show that, compared to the configuration without rear guide vanes, the fan assembly with added rear guide vanes exhibits a significantly reduced tangential velocity component in the outlet airflow, more uniform and orderly axial flow, and enhanced static pressure recovery. (Refer to...) Figure 12The performance comparison curves show that the fan assembly with added rear guide vanes can provide higher static pressure at the same air volume, thus improving the fan's pressure rise capability and efficiency.

[0052] The biomimetic sawtooth structure 50 suppresses aerodynamic noise in several ways. When the rotating airflow reaches the leading edge of the rear guide vane module 30, the irregular edge formed by the convex teeth 51 and concave teeth 52 of the biomimetic sawtooth structure 50 alters the interaction between the airflow and the leading edge. In the case of a conventional leading edge without a sawtooth structure, the airflow separates synchronously along the leading edge line, forming coherent vortex shedding and generating strong narrowband noise. In the case of a leading edge with a sawtooth structure, the separation time and intensity of the airflow at each sawtooth position are inconsistent, and the resulting vortex shedding is spatially and temporally dispersed, reducing coherence. The noise energy changes from a narrowband distribution to a broadband distribution, and the subjective perceived sharpness of the noise decreases. Furthermore, the three-dimensional geometric features of the sawtooth structure enhance the mixing and dissipation of the airflow, accelerate the attenuation of small-scale vortices, and reduce the secondary noise generated by the interaction between vortices and the downstream blade surface.

[0053] In terms of modular assembly, the independent molding and detachable connection design of the rear guide vane module 30 facilitates the production, assembly, and maintenance of the wind turbine components. During production, each rear guide vane module 30 can be independently injection molded; mold design and molding process optimization can be performed on a per-module basis, reducing mold complexity and molding difficulty. During assembly, operators can sequentially connect each rear guide vane module 30 to the air guide ring body 20 and adjacent rear guide vane modules 30 via the expansion locking mechanism 40. The angle limiting structure 60 ensures the consistency of the installation angle between modules, eliminating the need for additional angle measurement and adjustment procedures. (Refer to...) Figure 3 and Figure 4 As can be seen from the assembly diagram, the assembly process of the rear guide vane module 30 is a sequential splicing type. The modules are positioned by the cooperation of the hollow mounting post 41 and the mounting hole 42, and locked by the insertion of the locking part 43. The entire assembly process does not require the use of screws or adhesives for fastening.

[0054] When the entire equipment is being maintained or upgraded, if a particular rear guide vane module 30 is damaged or requires aerodynamic optimization, it can be replaced individually without disassembling the entire guide vane body 20 or the fan assembly. During disassembly, the elastic forked portion 41a is returned to its retracted state by pulling out the locking member 43, releasing the locking engagement with the mounting hole 42, and then the target rear guide vane module 30 is removed from the assembly structure. After replacing the rear guide vane module 30, the maintenance is completed by repositioning and locking it. This modular maintainable design reduces the overall replacement cost due to partial damage and facilitates the adjustment and optimization of the rear guide vane's aerodynamic parameters according to actual operating needs throughout the product lifecycle.

[0055] When adapting to different operating conditions, various application scenarios have different requirements for parameters such as air volume, air pressure, impeller diameter, number of blades, and rotational speed of the fan. The aerodynamic parameters such as the profile, installation angle, and chord length of the rear guide vane need to match the design parameters of the upstream impeller to achieve the best rectification and diffusion effect. In this technical solution, the independently molded design of the rear guide vane module 30 allows for the development of different specifications of the rear guide vane module 30 for different operating conditions, while structural components such as the air guide ring body 20 and the motor bracket 12 can remain universal. When it is necessary to adapt to a new impeller design or operating condition, only the rear guide vane module 30 needs to be replaced, without the need to redesign and manufacture the entire fan assembly, thus shortening the product development cycle and reducing R&D costs.

[0056] The separate design of aerodynamic and load-bearing components eliminates the structural contradictions caused by the rear guide vane simultaneously undertaking the dual functions of aerodynamic rectification and motor load-bearing in traditional integrated structures. The motor bracket 12 is specifically designed to support the weight of the motor 10, and its cross-sectional dimensions, material selection, and connection method are optimized according to the requirements of the load-bearing structure, possessing sufficient load-bearing stiffness and fatigue life. The rear guide vane module 30 is constructed as a non-load-bearing component, and its structural design can focus on optimizing aerodynamic performance. The blades can be made thinner and more airfoil-shaped, and noise reduction features such as the biomimetic sawtooth structure 50 can be arranged at the leading edge without considering the impact on load-bearing capacity. The physical clearance groove 34 further cuts off the transmission path of motor vibration to the rear guide vane module 30, avoiding fatigue damage and noise radiation caused by forced vibration of the rear guide vane module 30.

[0057] The independently molded design of the rear guide vane module 30 offers cost advantages in mass production. The smaller size and weight of a single rear guide vane module 30 reduce the required injection mold size, lowering mold manufacturing and maintenance costs. Simultaneously, the smaller injection molded parts require lower tonnage injection molding equipment, allowing for production with smaller injection molding machines, thus controlling equipment investment and operating costs. In terms of mold design, the cavity shape of a single rear guide vane module 30 is relatively simple, making it easier to set the demolding direction and arrange the core-pulling mechanism, reducing the structural complexity of the mold. Furthermore, a single-specification rear guide vane module 30 can be combined in different quantities to accommodate guide vane bodies 20 of varying diameters, increasing component standardization and production volume, further reducing unit costs.

[0058] The aft guide vane module 30 is subjected to periodic aerodynamic loads from the airflow during operation. These loads include pressure loads on the blade surface and vortex-induced loads generated when the airflow passes around the blade edge. The damping and strengthening structure 70, through its annularly distributed stiffeners, disperses the aerodynamic loads from the blade surface to the root and surrounding areas, preventing load concentration in a localized area of ​​the blade surface and reducing local stress levels. Simultaneously, the arrangement of the stiffeners increases the overall stiffness of the aft guide vane module 30 structure, reduces the deformation of the blade under aerodynamic loads, ensures the stability of the blade profile during operation, and maintains the designed aerodynamic performance.

[0059] The vibration damping and strengthening structure 70 suppresses the transmission of high-frequency vibrations. The mechanical vibrations and aerodynamic excitations generated by the motor 10 and impeller 11 during operation contain certain high-frequency components. If these high-frequency vibrations are transmitted to the blade surface of the guide vane module 30, they will cause a high-frequency vibration response in the blade, which in turn radiates sound waves into the surrounding air, generating noise. The reinforcing ribs of the vibration damping and strengthening structure 70 structurally form branch points for multiple vibration transmission paths. Vibration energy is distributed and dissipated at these branch points, reducing the vibration energy reaching the blade surface. Furthermore, the presence of the reinforcing ribs alters the vibration modal characteristics of the guide vane module 30, causing its natural frequencies to avoid the main excitation frequencies and reducing the occurrence of resonance amplification effects.

[0060] In summary, the combined wind turbine assembly with biomimetic serrated rear guide vanes disclosed in this invention achieves functional separation between aerodynamic and load-bearing components. The rear guide vane module 30 is independently formed and detachably connected to the air guide ring body 20 via an expansion locking mechanism 40, providing ample design freedom for aerodynamic optimization of the rear guide vane. The biomimetic serrated structure 50 utilizes the decomposition effect of the serrations on the airflow vortex structure to suppress aerodynamic noise generation. The angle limiting structure 60 ensures the accuracy and consistency of the installation angle during modular assembly. The physical clearance groove 34 achieves vibration isolation between the rear guide vane module 30 and the motor bracket 12. The three-dimensional twisted blade profile matches the spiral flow field at the upstream impeller outlet. The vibration damping and strengthening structure 70 disperses aerodynamic loads and suppresses the transmission of high-frequency vibrations. The shrinkage and thinning structure 80 solves the surface shrinkage problem during injection molding. These technical features work together to improve the wind turbine assembly of this invention in terms of structural reliability, aerodynamic efficiency, noise control, ease of assembly and maintenance, and manufacturing economy.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An axial flow fan assembly comprising detachable biomimetic serrated rear guide vanes, including a motor (10), an impeller (11), and a motor bracket (12), wherein the motor (10) is fixed on the motor bracket (12), and the impeller (11) is poweredly connected to the motor (10) to achieve airflow delivery, characterized in that: The fan assembly also includes a guide ring body (20); and several independently formed rear guide vane modules (30), which are arranged in an array along the circumferential direction of the guide ring body (20); The rear guide vane module (30) is constructed as a non-load-bearing component. The rear guide vane module (30) includes blades extending radially. The blades are three-dimensional twisted curved surfaces and are detachably fixed to the air guide ring body (20) by an expansion locking mechanism (40) to match the spiral flow field at the outlet of the upstream impeller (11) and to achieve deswirl and diffusion of the rotating airflow containing tangential components in the blade channel. The leading edge of the rear guide vane module (30) is provided with a biomimetic sawtooth structure (50) in at least a part of the region. The biomimetic sawtooth structure (50) is composed of a number of convex teeth (51) and concave teeth (52) arranged continuously along the span. The rear guide vane module (30), the expansion locking mechanism (40) and the biomimetic sawtooth structure (50) work together to achieve rectification, noise reduction and vibration isolation of the rotating airflow.

2. The wind turbine assembly as described in claim 1, characterized in that, The expansion locking mechanism (40) includes a hollow mounting post (41) integrally formed on one side of the root of the rear guide vane module (30), and a mounting hole (42) integrally formed on the other side of the root of the rear guide vane module (30) and adapted to the hollow mounting post (41); and a separate locking member (43). The hollow mounting post (41) has at least two radially expandable elastic bifurcations (41a) at its end; the locking member (43) is adapted to be installed in the hollow mounting post (41). When the locking member (43) is inserted axially, it forces the elastic bifurcations (41a) to expand radially, thereby forming an interference lock fit with the inner wall of the mounting hole (42).

3. The wind turbine assembly as described in claim 2, characterized in that, A locking part (41b) is also provided on one side of the elastic bifurcation part (41a). After the hollow mounting post (41) is locked with the mounting hole (42), the locking part (41b) and the edge of the mounting hole (42) are pressed into contact.

4. The wind turbine assembly as described in claim 2, characterized in that, The expansion locking mechanism (40) also integrates an angle limiting structure (60), which includes: a positioning boss (61) protruding from the connecting surface on one side of the root of the rear guide vane module (30), and a positioning groove (62) recessed on the mating surface on the other side of the root of the rear guide vane module (30). The positioning boss (61) and the positioning groove (62) cooperate to define the installation angle between two adjacent rear guide vane modules (30).

5. The wind turbine assembly as described in claim 1, characterized in that, The outline of the biomimetic sawtooth structure (50) is defined by a trigonometric function curve and satisfies the following geometric parameters: tooth height B is 3mm to 10mm; tooth pitch A is 10mm to 50mm; the biomimetic sawtooth structure (50) covers 30% to 95% of the total length of the leading edge and extends from the inside to the outside of the rear guide vane module (30) to cover the blade tip area with high airflow velocity; the rear guide vane module (30) is injection molded from glass fiber reinforced engineering plastic, and its blade body thickness is 3mm to 8mm, and a lightweight hollow structure (31) is provided on the non-aerodynamic working surface of the blade sidewall, and the edge of the hollow structure (31) is provided with reinforcing ribs (32) to maintain rigidity.

6. The wind turbine assembly as described in any one of claims 1 to 5, characterized in that, The rear guide vane module (30) also includes a sidewall diffuser section (33), which is located at the sidewall connection of the rear guide vane module (30). Its cross-sectional area gradually increases along the flow direction of the airflow and is used to assist in converting the kinetic energy of the airflow into static pressure energy. A rear guide vane fixing foot (35) is provided on one side of the sidewall diffuser section (33).

7. The wind turbine assembly as described in claim 1, characterized in that, The fan assembly also includes a fan panel (14), the motor bracket (12) is directly connected to the fan panel (14) or an external structure to bear the weight of the motor, a mesh cover (13) is provided on one side of the impeller (11), the rear guide vane module (30) and the motor bracket (12) are spatially independent and are provided with a physical clearance groove (34) to prevent motor vibration from being directly transmitted to the rear guide vane module (30).

8. The wind turbine assembly as described in claim 1, characterized in that, The blade cross section of the rear guide vane module (30) is an airfoil cross section at different radial positions, and the blade cross section installation angle and chord length change continuously in the radial direction; wherein, at the first radial position, the installation angle is 50° to 60° and the chord length is 70mm to 80mm, and at the second radial position, the installation angle is 60° to 70° and the chord length is 70mm to 80mm. The first radial direction is smaller than the second radial direction, thereby making the blade as a whole have a three-dimensional spatial twisted curved surface shape to match the spiral flow field at the outlet of the upstream impeller (11), and maintain a smooth transition of installation angle and chord length at the intermediate radial position between the first radial position and the second radial position.

9. The wind turbine assembly as claimed in claim 1, characterized in that, The rear guide vane module (30) is also provided with an annular damping and strengthening structure (70), which is an integrated reinforcing rib (32) surrounding the rear guide vane body. It is used to disperse aerodynamic loads and improve the overall structural rigidity, while suppressing the transmission of high-frequency vibrations on the guide vane surface.

10. The wind turbine assembly as claimed in claim 5, characterized in that, The rear guide vane module (30) has a shrinkage reduction structure (80) in the local uneven wall thickness area to eliminate surface shrinkage defects caused by uneven cooling shrinkage during injection molding.

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