Axial flow fan blade and fan comprising same

Abstract

This invention provides an axial flow fan blade and a fan comprising it, including a hub and blades; the blade includes several base circle sections sequentially from the inner edge to the outer edge; the contour line SP of each base circle section is generated by a first polynomial function; the starting points of each contour line SP are connected together to form the leading edge of the blade, which is a large-radius curved surface and is generated by a second polynomial function; the chord length L of each contour line SP is generated by a third polynomial function; the suction and pressure surfaces of the blade from the inner edge to the outer edge are both curved surface structures, which are generated by a first sine series function through boundary mixing; the ending points of each contour line SP are connected together to form the trailing edge of the blade, which is a wavy curved surface structure and is generated by a second sine series function. The axial flow fan blade and trailing edge of this invention are based on a multi-frequency harmonic superposition and collaborative optimization design, which significantly reduces the power consumption of the fan blade and greatly suppresses noise generation while meeting airflow requirements.

Description

Technical Field

[0001] This invention relates to the field of wind turbine technology, and in particular to an axial flow fan blade and a fan comprising the same. Background Technology

[0002] With increasing global demands for energy efficiency and environmental protection, air conditioning equipment, as a crucial household appliance, faces an urgent need to improve its energy efficiency ratio and reduce energy consumption. Axial flow fans, due to their simple structure, large air volume, and high efficiency, are widely used in air conditioners, ventilation systems, and other fields. However, ordinary axial flow fans are prone to generating significant aerodynamic noise during operation, mainly due to the interaction between the blades and the airflow, as well as the shedding of trailing vortices. This not only affects the user experience but may also cause noise pollution to the environment.

[0003] Furthermore, as a crucial energy-consuming component of the outdoor unit of an air conditioner, the performance optimization of axial fan blades is of great significance for improving the overall energy efficiency of the system. By optimizing the fan blade design, sufficient airflow can be maintained while reducing motor power consumption and operating noise, thus achieving dual optimization of energy efficiency and noise reduction. Existing axial fan blades for outdoor air conditioners typically need to meet the following performance requirements:

[0004] 1. Ensure sufficient airflow to meet heat dissipation requirements;

[0005] 2. Low operating energy consumption, reducing power consumption and motor load;

[0006] 3. Meets noise control standards and complies with environmental regulations.

[0007] However, there is a trade-off between airflow, energy consumption, and noise: increasing airflow usually requires increasing impeller power consumption and leads to increased aerodynamic noise. Therefore, there is an urgent need to develop an axial fan blade design that can meet airflow requirements while also achieving low energy consumption and low noise at the same rotational speed, in order to achieve an optimal balance among the three factors. Summary of the Invention

[0008] The purpose of this invention is to provide an axial flow fan blade and a fan containing the same, so as to solve the technical problems of unreasonable axial flow fan blade design in the prior art, which cannot simultaneously meet the requirements of large air volume, low power consumption and low noise.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] This invention provides an axial flow fan blade, comprising a hub and multiple blades; all the blades are arranged circumferentially along the hub; each blade includes several base circle sections in sequence from its inner edge to its outer edge; the contour line SP of each base circle section is generated by a first polynomial function; the starting points of each contour line SP are connected together to form the blade leading edge, which is a large-radius curved surface and is generated by a second polynomial function; the chord length L of each contour line SP is generated by a third polynomial function; the suction surface and pressure surface of the blade in the direction from its inner edge to its outer edge are both curved surface structures, which are generated by a first sine series function through boundary mixing; the ending points of each contour line SP are connected together to form the blade trailing edge, which is a wavy curved surface structure and is generated by a second sine series function.

[0011] The axial flow fan blade of this invention utilizes a multi-objective optimization design method, employing five polynomial functions to precisely control the blade cross-sectional profile, leading edge curvature, chord length distribution, surface curvature, and trailing edge wave morphology, effectively improving the airflow field distribution and suppressing the generation and development of separation vortices. The wave-shaped trailing edge structure can disperse detached vortices and reduce turbulent noise; the large-arc leading edge enhances the guiding capability of the inlet airflow, increasing airflow while reducing flow losses. This design achieves a 25% reduction in power consumption and a 0.5-1 dB(A) reduction in fan noise at the same rotational speed, significantly outperforming traditional straight-tailing-edge blades, achieving synergistic optimization of airflow, energy efficiency, and quietness.

[0012] As a further improvement of the present invention, the base circle section includes six base circle sections, namely the first to the sixth base circle sections; the relationship between the radius of each base circle section and the radius R of the blade is as follows: the radius of the first base circle section R1 = 0.364R, the radius of the second base circle section R2 = 0.553R, the radius of the third base circle section R3 = 0.692R, the radius of the fourth base circle section R4 = 0.808R, the radius of the fifth base circle section R5 = 0.909R, and the radius of the sixth base circle section R6 = R.

[0013] The axial flow fan blade of this invention constructs a non-uniform blade chord length and twist angle gradient by setting the radial distribution of six key cross-sections, thereby optimizing the aerodynamic load distribution along the spanwise direction and avoiding local stall. The parameters of each base circle cross-section are iteratively simulated through fluid dynamics to ensure that efficient flow characteristics are maintained under different operating conditions.

[0014] As a further improvement of the present invention, the first polynomial function includes the pressure surface profile cylindrical coordinate function f. z (θ) and the cylindrical coordinate function g of the suction surface profile z (θ); where:

[0015] f z (θ)=aθ 5 +bθ4 +cθ 3 +dθ 2 +eθ+f;

[0016] g z (θ)=Aθ 5 +Bθ 4 +Cθ 3 +Dθ 2 +Eθ+F; where θ is the central angle, and a, b, c, d, e, f, A, B, C, D, E, and F are all coefficients.

[0017] This invention achieves precise control over the aerodynamic shape of the blade cross-section by accurately fitting the cylindrical coordinate distribution of the pressure and suction surfaces using a fifth-order polynomial, effectively improving the lift-to-drag ratio. The coefficients a to f and A to F are optimized using a multi-objective genetic algorithm, balancing the requirements of high airflow, low noise, and a wide operating range. This maintains good airflow adhesion characteristics at different angles of attack, significantly enhancing the overall aerodynamic efficiency and stability of the blade.

[0018] As a further improvement of the present invention, the second polynomial function is the relative bending angle function β(R). x ), β(R) x )=-2E-06(R x ) 3 +0.001(R x ) 2 -3.458; where R x For each base circle cross-section radius, in mm, β(R) x () represents the relative bend angle at different base circle sections.

[0019] This invention constructs a third-order polynomial relative bend angle distribution function to achieve a smooth transition and optimal load distribution of the blade spanwise bend angle, effectively suppressing radial flow deviation. Aerodynamic simulation and experimental verification show that β(Rx) forms a reasonable pressure gradient within the range of 0.364R to R, avoiding airflow separation and improving the blade's work capacity. This function ensures stable aerodynamic performance under different speed conditions, enhancing the overall impeller efficiency and anti-stall capability.

[0020] As a further improvement of the present invention, the relative bend angle includes an initial relative bend angle βs corresponding to the first base circle section and a final relative bend angle βe corresponding to the sixth base circle section; wherein: βs∈[3°, 6°], βe∈[35°, 37°].

[0021] This invention ensures good air intake conditions at the blade root and sufficient work capacity at the blade tip by setting the range of initial relative bend angle βs and final relative bend angle βe. The bend angle distribution gradient has been verified through multi-condition simulations, achieving optimal aerodynamic load distribution at rated speed and effectively reducing secondary flow losses. Combining fifth-order polynomial profile control with third-order bend angle function adjustment enables the blade to maintain efficient and stable operation over a wide flow range, significantly improving the overall performance of the axial flow fan blade.

[0022] As a further improvement of the present invention, the third polynomial function is the chord length function L(Rx) of each base circle section, L(R... x )=-7E-08(R x ) 5 +7E-05(R x ) 4 -0.0269(R x ) 3 +4.9019(R x ) 2 -431.5(R x ) +14777; where: R x The radius of each base circle section is in mm.

[0023] As a further improvement of the present invention, the first sinusoidal series function is the height function H(x) of each base circle section.

[0024]

[0025] Where x is the axial distance from the center of the circle. For leaf height, A k For amplitude, w k For frequency, φ k For phase.

[0026] As a further improvement of the present invention, the amplitude A k >0, the frequency w k >0.

[0027] As a further improvement of the present invention, the second sinusoidal series function is the trailing edge curve axial height function F(x).

[0028]

[0029] in, For amplitude, For frequency, For phase.

[0030] The present invention provides a fan, including the axial flow fan blades.

[0031] The wind turbine of this invention features axial flow blades that significantly improve aerodynamic efficiency while ensuring structural strength through multi-parameter collaborative optimization design. The blade spanwise bending angle is coupled and controlled with chord length and height functions to achieve a uniform flow field distribution, effectively suppressing boundary layer separation and eddy generation. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the axial flow fan blade of the present invention;

[0034] Figure 2 This is a schematic diagram of the pressure surface and suction surface structure of the axial flow fan blade of the present invention;

[0035] Figure 3 This is a schematic diagram of the base circle radii of the axial flow fan blades of the present invention;

[0036] Figure 4 This is a schematic diagram of the outline of each base circle of the axial flow fan blade of the present invention;

[0037] Figure 5 This is a schematic diagram of the relative bending angle of the leading edge contour line of the axial flow fan blade of the present invention;

[0038] Figure 6 This is a schematic diagram of the chord length of the base circle outline of the axial flow fan blade of the present invention;

[0039] Figure 7 This is a schematic diagram of the cross-sectional structure of the axial flow fan blade of the present invention;

[0040] Figure 8 This is a schematic diagram of the cross-sectional structure of the multi-frequency harmonic superposition optimization design of the axial flow fan blade of the present invention;

[0041] Figure 9 This is a schematic diagram of curve fitting for the multi-frequency harmonic superposition optimization design of the axial flow fan blades of the present invention;

[0042] Figure 10 This is a schematic diagram of the tail edge optimized design structure based on multi-frequency harmonic superposition in this invention;

[0043] Figure 11 This is a power comparison curve of the axial flow fan blades of the present invention at the same rotational speed;

[0044] Figure 12 This is a noise comparison curve of the axial flow fan blades of the present invention at the same rotational speed;

[0045] Figure 13 This is a partial three-dimensional structural schematic diagram of the axial flow fan blade of the present invention.

[0046] In the picture:

[0047] 1. Wheel hub;

[0048] 2. Leaves;

[0049] 3. Leading edge of the leaf;

[0050] 4. Outer edge of the leaf;

[0051] 5. Inner edge of the leaf;

[0052] 6. Blade tip;

[0053] 7. The outer edge of the blade is bent;

[0054] 8. Pressure surface;

[0055] 9. Suction surface. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0057] like Figures 1-13 As shown, this invention provides an axial flow fan blade based on multi-frequency harmonic superposition optimization design, including a hub 1 and multiple blades 2; all blades 2 are arranged circumferentially along the hub 1; the blades 2 include several base circle sections in sequence from the inner edge 5 to the outer edge 4; the contour line SP of each base circle section is generated by a first polynomial function; the starting points of each contour line SP are connected together to form the blade leading edge, which is a large-radius curved surface and is generated by a second polynomial function; the chord length L of each contour line SP is generated by a third polynomial function; the suction surface and pressure surface of the blade from the inner edge to the outer edge are both curved surface structures, which are generated by a first sine series function through boundary mixing; the ending points of each contour line SP are connected together to form the blade trailing edge, which is a wavy curved surface structure and is generated by a second sine series function.

[0058] Specifically, blade 2 includes a leading edge 3, an outer edge 4, an inner edge 5, a trailing edge 6, a pressure surface 8, and a suction surface 9; the outer edge 4 has an outer edge bend 7. The leading edge 3 is a large-angle arc structure, and the trailing edge 6 is a wavy airfoil trailing edge structure. The windward surface of the blade in this invention does not have a windward groove, and the trailing edge is locally concave to form a wavy shape. By controlling the chord length and relative bending angle parameters of different basic blade profiles of the axial flow fan, the trailing edge of the blade and the gradually changing corrugated structure of the blade surface are better matched, avoiding excessively large local velocity gradients. This allows the airflow to better converge at the blade outlet, improving the wind gathering effect and dispersing the noise spectrum.

[0059] The axial flow fan blade of this invention utilizes a multi-objective optimization design method, employing five polynomial functions to precisely control the blade cross-sectional profile, leading edge curvature, chord length distribution, surface curvature, and trailing edge wave morphology, effectively improving the airflow field distribution and suppressing the generation and development of separation vortices. The wave-shaped trailing edge structure can disperse detached vortices and reduce turbulent noise; the large-arc leading edge enhances the guiding capability of the inlet airflow, increasing airflow while reducing flow losses. This design achieves a 25% reduction in power consumption and a 0.5-1 dB(A) reduction in fan noise at the same rotational speed, significantly outperforming traditional straight-tailing-edge blades, achieving synergistic optimization of airflow, energy efficiency, and quietness.

[0060] As a further improvement of the present invention, the base circle section includes six base circle sections, namely the first to the sixth base circle sections; the relationship between the radius of each base circle section and the radius R of the blade is as follows: the radius of the first base circle section R1 = 0.364R, the radius of the second base circle section R2 = 0.553R, the radius of the third base circle section R3 = 0.692R, the radius of the fourth base circle section R4 = 0.808R, the radius of the fifth base circle section R5 = 0.909R, and the radius of the sixth base circle section R6 = R.

[0061] The axial flow fan blade of this invention constructs a non-uniform blade chord length and twist angle gradient by setting the radial distribution of six key cross-sections, thereby optimizing the aerodynamic load distribution along the spanwise direction and avoiding local stall. The parameters of each base circle cross-section are iteratively simulated through fluid dynamics to ensure that efficient flow characteristics are maintained under different operating conditions.

[0062] As a further improvement of the present invention, the first polynomial function includes the pressure surface profile cylindrical coordinate function f. z (θ) and the cylindrical coordinate function g of the suction surface profile z (θ); where:

[0063] f z (θ)=aθ 5 +bθ 4 +cθ 3 +dθ 2 +eθ+f;

[0064] g z (θ)=Aθ 5 +Bθ 4 +Cθ 3 +Dθ 2 +Eθ+F; where θ is the central angle, and a, b, c, d, e, f, A, B, C, D, E, and F are all coefficients.

[0065] This invention achieves precise control over the aerodynamic shape of the blade cross-section by accurately fitting the cylindrical coordinate distribution of the pressure and suction surfaces using a fifth-order polynomial, effectively improving the lift-to-drag ratio. The coefficients a to f and A to F are optimized using a multi-objective genetic algorithm, balancing the requirements of high airflow, low noise, and a wide operating range. This maintains good airflow adhesion characteristics at different angles of attack, significantly enhancing the overall aerodynamic efficiency and stability of the blade.

[0066] As a further improvement of the present invention, the second polynomial function is the relative bending angle function β(R). x ), β(R) x )=-2E-06(R x ) 3 +0.001(R x ) 2 -3.458; where R x For each base circle cross-section radius, in mm, β(R) x () represents the relative bend angle at different base circle sections.

[0067] This invention constructs a third-order polynomial relative bend angle distribution function to achieve a smooth transition and optimal load distribution of the blade spanwise bend angle, effectively suppressing radial flow deviation. Aerodynamic simulation and experimental verification show that β(Rx) forms a reasonable pressure gradient within the range of 0.364R to R, avoiding airflow separation and improving the blade's work capacity. This function ensures stable aerodynamic performance under different speed conditions, enhancing the overall impeller efficiency and anti-stall capability.

[0068] As a further improvement of the present invention, the relative bend angle includes an initial relative bend angle βs corresponding to the first base circle section and a final relative bend angle βe corresponding to the sixth base circle section; wherein: βs∈[3°, 6°], βe∈[35°, 37°].

[0069] This invention ensures good air intake conditions at the blade root and sufficient work capacity at the blade tip by setting the range of initial relative bend angle βs and final relative bend angle βe. The bend angle distribution gradient has been verified through multi-condition simulations, achieving optimal aerodynamic load distribution at rated speed and effectively reducing secondary flow losses. Combining fifth-order polynomial profile control with third-order bend angle function adjustment enables the blade to maintain efficient and stable operation over a wide flow range, significantly improving the overall performance of the axial flow fan blade.

[0070] As a further improvement to the present invention, the third polynomial function is the chord length function L(Rx) of each base circle section, L(R... x )=-7E-08(R x ) 5 +7E-05(R x ) 4 -0.0269(R x ) 3 +4.9019(R x ) 2 -431.5(R x ) +14777; where: R x The radius of each base circle section is in mm.

[0071] As a further improvement of the present invention, the first sine series function is the height function H(x) of each base circle section.

[0072]

[0073] Where x is the axial distance from the center of the circle. For leaf height, A k For amplitude, w k For frequency, φ k For phase.

[0074] As a further improvement of the present invention, amplitude A k >0, frequency w k >0.

[0075] The blade 2 in the axial flow fan blade is based on a multi-frequency harmonic superposition optimization design structure, which can achieve smooth airflow transition, effectively suppress turbulence and eddy generation, improve flow stability, and reduce local pressure fluctuations, thereby significantly delaying airflow separation. This design enhances flow control capability by introducing a controllable micro-disturbance stable boundary layer, and significantly improves the fan blade's wind-gathering effect while reducing the generation of fan blade noise sources.

[0076] As a further improvement of the present invention, the second sinusoidal series function is the trailing edge curve axial height function F(x).

[0077]

[0078] in, For amplitude, For frequency, For phase.

[0079] In addition to the localized wave shape in the longitudinal direction, the present invention also features a gradually changing wave shape in the axial direction. The suction and pressure surfaces of the blades adopt a gradually changing corrugated structure design, which makes the airflow transition more smoothly, thereby reducing the generation of turbulence and eddies, reducing fluctuations between high-pressure and low-pressure areas, and thus reducing the possibility of airflow separation.

[0080] By controlling the chord length and relative bend angle parameters of different basic blade profiles of axial flow fan blades, the trailing edge, pressure surface, and suction surface of the blades are all optimized by multi-frequency superposition. Through the matching of fluid dynamic characteristics, excessive local velocity gradients can be avoided, thereby allowing the airflow to converge better at the blade outlet, improving the wind gathering effect, dispersing the noise spectrum, making it smoother, significantly reducing power fluctuations and aerodynamic noise, and achieving high efficiency and low noise synergistic optimization.

[0081] The axial flow fan blade provided by this invention has three blades 2. Through the above design, the three-bladed low-pressure axial flow fan blade provided by this invention can reduce noise and power while meeting the air volume requirements. It can significantly improve the aerodynamic performance of the fan blade, reduce noise, and increase efficiency. By optimizing the airflow distribution, it can significantly reduce the generation of turbulence and eddies, improve the wind gathering effect, and reduce noise.

[0082] like Figures 1-13 As shown, the present invention provides a fan including axial flow fan blades.

[0083] Specifically, the axial flow fan blades include a hub 1 and blades 2. There are three blades 2, which are evenly distributed around the hub 1 and fixedly connected to the outer circumference of the hub 1.

[0084] The blade 2 consists of a leading edge 3, an airfoil trailing edge 6, an outer edge 4, an inner edge 5, an outer edge bend 7, a pressure surface 8, and a suction surface 9. The leading edge 3 is located on the windward side of the blade, and its curvature is designed by fitting multiple circular arcs to reduce inlet impact loss. The trailing edge 6 of the airfoil adopts an asymmetric thin-walled structure and combines the axial height function F(x) to control its geometry, effectively reducing the intensity of the wake vortex.

[0085] Specifically, the radius of the axial flow fan blade is R, which in this embodiment is R=275mm; the radii corresponding to the six base circle sections are R1=0.364R, R2=0.553R, R3=0.692R, R4=0.808R, R5=0.909R, and R6=R, respectively; the blade shape is generated by controlling the radius of the base circle, such as... Figure 3 As shown.

[0086] The pressure surface 8 and suction surface 9 of blade 2 are generated by boundary blending of the contour lines SP1, SP2, SP3, SP4, SP5, and SP6 (circular arc segments) on the six base circular sections, as shown below. Figure 4As shown, the contour lines SP1, SP2, SP3, SP4, SP5, and SP6 are composed of the pressure surface 8 and suction surface 9 of the blade 2, and the pressure surface 8 and suction surface 9 of the contour lines SP1, SP2, SP3, SP4, SP5, and SP6 are determined by the polynomials fz(θ) and gz(θ), respectively.

[0087] The polynomial equation for pressure surface 8 is (cylindrical coordinates) fz(θ) = aθ 5 +bθ 4 +cθ 3 +dθ 2 +eθ+f, where θ is the central angle, and the preferred values ​​of the coefficients in the equation are shown in Table 1:

[0088] Table 1 Optimal values ​​of applicability coefficients for pressure surface airfoil equations

[0089]

[0090] The suction surface 9 of the blade is fitted by the coordinate points of the contour lines on the six base circle sections SP1~SP6. The polynomial equation of the suction surface 9 is (cylindrical coordinates) g. z (θ)=Aθ 5 +Bθ 4 +Cθ 3 +Dθ 2 +Eθ+F, where θ is the central angle, and the preferred values ​​of the coefficients in the equation are shown in Table 2:

[0091] Table 2 Optimal values ​​of applicability coefficients for suction surface airfoil equations

[0092]

[0093] The initial relative bend angle of the leading edge 3 of the blade is β s The relative bend angle at termination is β. e ,like Figure 5 As shown, the relative bending angles β(Rx) of the three leading edges of the blade and the radius Rx of each base circle are given by the polynomial β(Rx) = -2E-06(Rx). 3 +0.001(Rx) 2 -3.458 is determined, where the initial relative bending angle β s (βs∈[3°, 6°], preferably β) s =4.35°; Termination relative bend angle β e (βe∈[35°, 37°], preferably β) s =36.36°, and the radius of each base circle Rx∈[100mm, 275mm].

[0094] The chord length L(Rx) of each base circle section of the blade and the radius Rx of each base circle are given by the polynomial L(Rx) = -7E-08(Rx).5 +7E-05(Rx) 4 -0.0269(Rx) 3 +4.9019 (Rx) 2 -431.5(Rx) +14777 is determined, where L(Rx)∈[190mm,495mm], preferably L(R1)=192.97mm, L(R2)=252mm, L(R3)=308.76mm, L(R4)=337.72mm, L(R5)=427.88mm, and L(R6)=490.26mm. It should be noted that the blade chord length here is the commonly used definition in this field, which is the distance between the two ends of the blade arc segment after it is flattened in space.

[0095] In this invention, the pressure surface and suction surface are controlled by the arc length of the base circle contour line, so that the pressure surface and suction surface of the entire blade smoothly transition into a gradually changing corrugated shape, forming a concave-convex shape, which makes the airflow transition more smoothly, thereby reducing the generation of blade turbulence and eddies, and helping to improve the stability of airflow.

[0096] The blade surface of this invention has a radial direction extending outward from the inner edge of the blade, and the blade thickness d = 4 mm, as shown below. Figure 7 As shown. Figure 8 In the two-dimensional plane shown, the radius of the wind turbine blade is R, which in this embodiment is R=275mm, and x is the axial distance from the center of the circle. , The blade height is represented by the radial coordinate R = 275 mm, and x is the axial distance from the center of the circle. , Leaf height, radial coordinate , , is the outer edge of the leaf. Let x be the inner edge of the blade, and let x be a negative value representing the radial position extending outward from the blade root (axis), and let H(x) satisfy the mathematical expression:

[0097] ;

[0098] Among them, the optimized parameters were verified by aerodynamic performance, and the optimal value was: Hx and the height of the horizontal plane;

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] In the expression, amplitude ,frequency To ensure the curve is smooth and free of physically unrealizable oscillations, phase Make the cross-sectional curvature Internally continuous and conductive, avoiding airflow separation. For example... Figure 9 The figure shows a schematic diagram of the fitting curve of the blade structure based on the multi-frequency harmonic superposition optimization design.

[0106] The blades, based on a multi-frequency harmonic superposition-based optimized design, achieve smooth airflow transition, effectively suppress turbulence and eddy generation, improve flow stability, and reduce local pressure fluctuations, thereby significantly delaying airflow separation. This design enhances flow control capabilities by introducing a controllable micro-disturbance stable boundary layer, significantly improves the blade's wind-gathering effect, and reduces the generation of blade noise sources.

[0107] like Figure 10 As shown, in a two-dimensional cross-section, with O as the center, the trailing edge axial direction X presents a multi-frequency harmonic superposition design structure. In this embodiment, the blade radius is R = 275 mm, F(x) is the axial height on the trailing edge curve, and the distance from the axial direction to the center is x ∈ (-0.9R, -0.19R) mm. The multi-frequency harmonic superposition optimization design curve F(x) satisfies the mathematical expression:

[0108]

[0109] In the expression, For amplitude, For frequency, For the phase, the optimized parameters have been verified through aerodynamic performance, and the optimal values ​​are:

[0110] Table 3 Optimized values ​​of coefficients for trailing edge design equations based on multi-frequency harmonic superposition

[0111]

[0112] The blade trailing edge, pressure surface, and suction surface of this invention all adopt a multi-frequency superposition optimization design, and the following effects can be achieved through fluid dynamic characteristic matching:

[0113] (1) Significantly improves the wind gathering effect and enhances the wind energy conversion efficiency;

[0114] (2) Effectively suppresses the separation of trailing edge turbulence from the boundary layer, reducing flow resistance;

[0115] (3) Simultaneously reduce power fluctuations and aerodynamic noise to achieve high efficiency and low noise synergistic optimization.

[0116] from Figure 11 , Figure 12 Experimental data shows that, while meeting airflow requirements, the axial flow fan blades of this invention can reduce power consumption by an average of 25% at the same rotational speed. At the same rotational speed, the new fan blades reduce the input power of the original fan motor by approximately 50W, and at the same rotational speed, the noise level of the new fan blades is reduced by 0.5~1dB(A) compared to the original fan blades. Experiments demonstrate that this invention, through multi-frequency harmonic optimization design, simultaneously achieves a 25% reduction in input energy consumption and a 1.5 dB(A) noise reduction while maintaining constant airflow, effectively solving the technical bottlenecks of high power consumption and high noise in the original fan system.

[0117] The wind turbine of this invention employs a multi-parameter collaborative optimization design for its axial flow blades. By controlling the chord length and relative bend angle parameters of different basic blade profiles, the trailing edge, pressure surface, and suction surface of the blades are all optimized through multi-frequency superposition. This significantly improves aerodynamic efficiency while ensuring structural strength. The blade spanwise bend angle is coupled and controlled with the chord length and height functions to achieve a uniform flow field distribution, effectively suppressing boundary layer separation and eddy generation.

[0118] First, it should be noted that "inward" refers to the direction towards the center of the storage space, while "outward" refers to the direction away from the center of the storage space.

[0119] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the purpose of facilitating and simplifying the description of the present invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0120] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0121] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0122] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0123] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0124] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An axial flow fan blade, comprising a hub and a plurality of blades; all said blades are arranged circumferentially along the hub; characterized in that, The blade comprises several base circle sections sequentially from its inner edge to its outer edge. The contour line SP of each base circle section is generated by a first polynomial function. The starting points of each contour line SP are connected to form the blade leading edge, which is a large-radius curved surface and is generated by a second polynomial function. The chord length L of each contour line SP is generated by a third polynomial function. The suction and pressure surfaces of the blade from its inner edge to its outer edge are both curved surfaces, generated by a first sine series function through boundary mixing. The ending points of each contour line SP are connected to form the blade trailing edge, which is a wavy curved surface structure and is generated by a second sine series function. The first sine series function is the height function H(x) of each base circle section. ； Where x is the axial distance from the center of the circle. For leaf height, A k For amplitude, w k For frequency, φ k For phase.

2. The axial fan blade of claim 1, wherein, The base circle section includes six base circle sections, namely the first to the sixth base circle sections; the relationship between the radius of each base circle section and the radius R of the blade is as follows: the radius of the first base circle section R1 = 0.364R, the radius of the second base circle section R2 = 0.553R, the radius of the third base circle section R3 = 0.692R, the radius of the fourth base circle section R4 = 0.808R, the radius of the fifth base circle section R5 = 0.909R, and the radius of the sixth base circle section R6 = R.

3. The axial fan blade of claim 1, wherein, The first polynomial function includes the pressure surface profile cylindrical coordinate function f. z (θ) and the cylindrical coordinate function g of the suction surface profile z (θ); where: f z (θ)=aθ 5 +bθ 4 +cθ 3 +dθ 2 +eθ+f; g z (θ)=Aθ 5 +Bθ 4 +Cθ 3 +Dθ 2 +Eθ+F; where θ is the central angle, and a, b, c, d, e, f, A, B, C, D, E, and F are all coefficients.

4. The axial fan blade of claim 2, wherein, The second polynomial function is the relative curvature function β(R) x ), β(R) x )=-2E-06(R x ) 3 +0.001(R x ) 2 -3.458; where R x is the radius of each base circle section in mm, and β(R x ) is the relative bend angle at different base circle sections.

5. The axial fan blade of claim 4, wherein, The relative bend angles include the initial relative bend angle βs corresponding to the first base circle section and the final relative bend angle βe corresponding to the sixth base circle section; where: βs∈[3°, 6°], βe∈[35°, 37°].

6. The axial fan blade of claim 2, wherein, The third polynomial function is the chord length function L(R) of each base circle section. x ), L(R x )=-7E-08(R x ) 5 +7E-05(R x ) 4 -0.0269(R x ) 3 +4.9019(R x ) 2 -431.5(R x ) +14777; where: R x The radius of each base circle section is in mm.

7. The axial fan blade of claim 1, wherein, the amplitude A k > 0, the frequency w k > 0.

8. The axial flow fan blade according to claim 1, characterized in that, The second sinusoidal series function is the axial height function F(x) of the trailing edge curve. in, For amplitude, For frequency, For phase.

9. A fan, characterized by Includes the axial flow fan blades as described in any one of claims 1-8.

Images