Mine axial flow fan

Abstract

The application discloses a mine axial flow fan, which comprises a hub, a plurality of blades, a plurality of first protrusions, a plurality of second protrusions and a plurality of sawteeth. The plurality of blades are arranged on the hub and are spaced along the circumference of the hub. The plurality of first protrusions are arranged on the leading edge of the blade and are arranged along the blade span. The first protrusions are used for breaking vortex to improve the flow state of the airflow. The plurality of second protrusions are arranged on the pressure surface of the blade and are spaced along the blade span. The second protrusions are used for inhibiting the turbulent flow fluctuation on the pressure surface of the blade and attenuating the Reynolds stress. The plurality of sawteeth are arranged on the trailing edge of the blade and are arranged along the blade span. The plurality of sawteeth are used for reducing the operation noise of the blade. The mine axial flow fan has the advantages of simple structure, small operation noise and the like.

Description

Technical Field

[0001] This invention relates to the field of mining machinery, specifically to a mining axial flow fan. Background Technology

[0002] Axial flow fans for mining are the core and key equipment of mine ventilation systems, and they operate continuously in harsh environments with high dust levels and complex working conditions.

[0003] Among related technologies, axial flow fans used in mines are noisy and have low ventilation efficiency. Summary of the Invention

[0004] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0005] The blades of mining fans have a simple structural design, and large-scale eddy currents and induced eddy currents are easily generated at the leading edge of the blades. This leads to turbulent airflow and intense turbulent pulsation in the boundary layer at the pressure surface, and large-area eddy current shedding at the trailing edge of the blades. As a result, the aerodynamic noise is high and the airflow stability is poor during the operation of the fan. Long-term high-intensity noise not only pollutes the underground working environment and endangers the health of workers, but also easily causes machine vibration, affecting the operational stability and service life of the fan.

[0006] The present invention aims to at least partially solve one of the technical problems in the related art.

[0007] Therefore, embodiments of the present invention propose a mining axial flow fan with low noise and high ventilation efficiency.

[0008] According to an embodiment of the present invention, a mining axial flow fan includes: a hub; a plurality of blades, all disposed on the hub and spaced apart circumferentially along the hub; a plurality of first protrusions, disposed on the leading edge of the blades and arranged sequentially along the spanwise direction of the blades, the first protrusions being used to break up eddies to improve airflow; a plurality of second protrusions, disposed on the pressure surface of the blades and arranged spaced apart along the spanwise direction of the blades, the second protrusions being used to suppress turbulent pulsation on the pressure surface of the blades and attenuate Reynolds stress; and a plurality of serrations, disposed on the trailing edge of the blades and arranged sequentially along the spanwise direction of the blades, the plurality of serrations being used to reduce blade operating noise.

[0009] The mining axial flow fan of this invention features a first protrusion, a second protrusion, and serrations on the leading edge, pressure surface, and trailing edge of the blades, respectively. The first protrusion at the leading edge breaks up large-scale eddies, suppresses the generation of leading-edge induced eddies, optimizes the internal flow field, and reduces aerodynamic noise at its source. The second protrusion on the pressure surface reconstructs the boundary layer flow field, achieves reasonable distribution of airflow, suppresses turbulent pulsations, attenuates Reynolds stress, and weakens stall noise. The trailing-edge serrations segment the wake and break up detached eddies, achieving broadband noise reduction. These three features work synergistically without increasing the complexity of the equipment structure or affecting ventilation efficiency. They effectively improve airflow separation, comprehensively optimize flow field characteristics, significantly reduce overall aerodynamic noise, and enhance the operational stability of the mining axial flow fan.

[0010] In some embodiments, the cross-sectional area of ​​the first protrusion gradually decreases in the direction away from the blade, and the top of the first protrusion is arc-shaped.

[0011] In some embodiments, the second protrusion extends along the chordal direction of the blade, and an airflow channel is defined between two adjacent second protrusions.

[0012] In some embodiments, the cross-sectional area of ​​the second protrusion is triangular or rectangular.

[0013] In some embodiments, the cross-sectional area of ​​the serrations gradually decreases in the direction away from the blade.

[0014] In some embodiments, a plurality of first protrusions and a plurality of second protrusions are spaced apart along the chordal direction of the blade, and / or, a plurality of first protrusions and the serrations are spaced apart along the chordal direction of the blade.

[0015] In some embodiments, the height of the saw teeth is greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0016] In some embodiments, the mining axial flow fan further includes a motor connected to the hub so that the motor drives the hub to rotate.

[0017] In some embodiments, the cross-sectional area of ​​the blade gradually decreases in the direction away from the hub.

[0018] In some embodiments, the blade, the first protrusion, the second protrusion, and the serrations are integrally formed. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a mining axial flow fan according to an embodiment of the present invention.

[0020] Figure 2 This is a top view of the blades of a mining axial flow fan according to an embodiment of the present invention.

[0021] Figure 3 This is a front view of the blades of a mining axial flow fan according to an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the blade structure of a mining axial flow fan according to an embodiment of the present invention.

[0023] Figure 5 This is a rear view of the blades of a mining axial flow fan according to an embodiment of the present invention.

[0024] 100. Axial flow fans for mining; 1. Hub; 2. Blade; 3. First protrusion; 4. Second protrusion; 5. Serration. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] The following description, with reference to the accompanying drawings, describes a mining axial flow fan 100 according to an embodiment of the present invention.

[0027] like Figures 1-5 As shown, the mining axial flow fan 100 according to an embodiment of the present invention includes a hub 1, multiple blades 2, multiple first protrusions 3, multiple second protrusions 4, and multiple serrations 5.

[0028] Multiple blades 2 are disposed on the hub 1 and spaced apart circumferentially along the hub 1. Multiple first protrusions 3 are disposed on the leading edge of the blades 2 and arranged sequentially along the span of the blades 2. The first protrusions 3 are used to break up vortices to improve airflow. Specifically, as shown in the figure... Figures 1-5 As shown, the hub 1 is circular, and the number of blades 2 can be set to multiple according to the actual situation. Multiple blades 2 are arranged sequentially along the circumference of the hub 1 and are driven to rotate synchronously by the hub 1 during operation. Each blade 2 has several first protrusions 3 arranged on its leading edge surface. The first protrusions 3 are continuously arranged along the extension direction from the root of the blade 2 to the tip of the blade.

[0029] The first protrusion 3 structure added to the leading edge can sever the large-scale vortex structure in the airflow, weaken and suppress the generation and development of the leading edge induced vortex of the blade 2, destroy the shedding law of the large-scale vortex, reduce vortex disturbance from the source of noise generation, significantly reduce the radiation intensity of aerodynamic noise, improve the airflow separation phenomenon inside the fan, make the airflow more stable and smooth, and effectively improve the operational stability of the mining axial flow fan 100.

[0030] Multiple second protrusions 4 are disposed on the pressure surface of the blade 2 and are spaced apart along the spanwise direction of the blade 2. The second protrusions 4 are used to suppress turbulent pulsation on the pressure surface of the blade 2 and attenuate Reynolds stress. Specifically, as shown in... Figures 1-5 As shown, the second protrusion 4 is set on the pressure surface of the blade 2 and is continuously arranged along the extension direction from the root to the tip of the blade 2. The second protrusion 4 itself will have a forced cutting and guiding effect on the boundary layer airflow flowing close to the wall, forcing the mainstream airflow to split along both sides of the protrusion and generate regular longitudinal swirling motion along the flow direction, thereby spontaneously forming a stable and orderly flow vortex field inside the boundary layer of the pressure surface. This directional micro-vortex can continuously stir the airflow near the wall, delay the thickening of the boundary layer and the separation of the airflow, weaken the development of disordered turbulence on the surface, and thus achieve the effect of suppressing turbulent pulsation and attenuating Reynolds stress. Thus, it can transform the stall noise that was originally concentrated and energy-concentrated during the operation of the wind turbine into a wide-bandwidth, low-amplitude background turbulence sound that is easy to decay naturally, thereby achieving a noise reduction effect.

[0031] Multiple serrations 5 are located at the trailing edge of the blade 2 and are arranged sequentially along the span of the blade 2. These serrations 5 are used to reduce the operating noise of the blade 2. Specifically, as shown... Figures 1-5 As shown, multiple serrations 5 are arranged on the trailing edge of blade 2 and continuously along the extension direction from the root to the tip of blade 2. Through the diversion effect of the serrations 5, the overall airflow separation area at the trailing edge is divided into multiple smaller areas, preventing the generation and periodic shedding of large-scale vortices. At the same time, the serrations 5 can guide the airflow to flow smoothly, break up large vortex structures and decompose them into small fragments, weakening vortex impact and airflow disturbance, thereby effectively reducing the overall aerodynamic noise of the fan and achieving noise reduction while ensuring ventilation efficiency.

[0032] The mine axial flow fan 100 of this invention is provided with a first protrusion 3, a second protrusion 4 arranged on the pressure surface, and a sawtooth structure 5 added to the trailing edge. The first protrusion 3 can effectively break up large-scale eddies, suppress the generation of leading-edge induced eddies, improve the internal airflow state, and reduce aerodynamic noise radiation from the sound source. The second protrusion 4 on the pressure surface can construct a vortex field, complete the redistribution of airflow, suppress turbulent pulsation, attenuate Reynolds stress, and convert high-intensity stall noise into low-amplitude, easily attenuated background turbulent sound. The sawtooth 5 on the trailing edge of the blade 2 can divide the wake region, disperse and break up large eddies, shorten the wake effect range, and achieve wideband noise reduction. The three work together to comprehensively optimize the flow field distribution, improve airflow separation, reduce aerodynamic noise across the entire frequency band, and significantly improve the operational stability of the mine axial flow fan 100 without increasing the complexity of the equipment structure or weakening the ventilation efficiency of the fan.

[0033] In some embodiments, the cross-sectional area of ​​the first protrusion 3 gradually decreases in the direction away from the blade 2, and the top of the first protrusion 3 is arc-shaped. Specifically, as shown in... Figures 1-5As shown, the cross-sectional area of ​​the first protrusion 3 gradually decreases along the direction away from the surface of the blade 2, forming a streamlined gradient structure. The top of the first protrusion 3 adopts a smooth arc design, which not only ensures smooth airflow but also enhances the vortex breaking effect. On the one hand, the gradual reduction of the cross-sectional area makes the windward surface of the first protrusion 3 in contact with the airflow form a smoothly transitioning streamlined profile, avoiding the generation of additional local vortices or airflow obstruction when the airflow hits the first protrusion 3, ensuring that the incoming flow can smoothly bypass the first protrusion 3 and reduce the increase in aerodynamic drag. On the other hand, the smooth arc design at the top not only further reduces airflow friction loss but also forms a gentle guiding and cutting effect on the airflow through the arc surface. When a large-scale vortex flows through the first protrusion 3, the arc top can accurately act on the core region of the vortex, gradually tearing it into smaller-scale vortices, while avoiding secondary vortex noise caused by the angular structure.

[0034] In some embodiments, the first protrusion 3 may adopt a whale fin-shaped biomimetic structure, which, based on the principle of fluid bionics, actively forms a controllable separation vortex at the airflow inlet. The streamlined contour of the whale fin can efficiently cut and break up the large-scale vortex structure of the incoming flow. Compared with the leading edge of the traditional blunt blade 2, this biomimetic shape can significantly optimize the leading edge flow field distribution, suppress vortex disturbance and airflow separation, effectively reduce high-frequency aerodynamic noise of 3kHz-8kHz, and achieve a noise reduction of about 4.6dB, greatly improving the overall acoustic performance of the fan.

[0035] In some embodiments, the second protrusion 4 extends along the chordal direction of the blade 2, and an airflow channel is defined between two adjacent second protrusions 4. Specifically, as Figures 1-5 As shown, each second protrusion 4 extends laterally from one side of the pressure surface of the blade 2 to the other side, and is arranged in a parallel and spaced manner. The sidewalls of adjacent second protrusions 4 and the pressure surface of the blade 2 together form a narrow airflow channel. Thus, the small-scale airflow that has been dispersed by the first protrusion 3 at the leading edge of the blade 2 will flow smoothly in a preset direction under the constraint and guidance of the channel. This avoids disordered diffusion or secondary separation of the airflow on the pressure surface and guides the airflow to the serrated 5 structure at the trailing edge of the blade 2, laying the foundation for the serrated 5 to further optimize the wake and reduce noise.

[0036] In some embodiments, the cross-sectional area of ​​the second protrusion 4 is triangular or rectangular. Specifically, the triangular cross-section has sharp edges and a stronger guiding and shearing effect, which can efficiently cut the boundary layer airflow and enhance the suppression of turbulent fluctuations. The rectangular cross-section has a regular structure and good stress stability, which can stably construct a continuous airflow channel and has stronger guiding properties. Therefore, by selecting the second protrusion 4 with a triangular or rectangular cross-section, the airflow control requirements under different operating conditions can be met, and it can be perfectly matched with the pressure surface of the blade 2, effectively maintaining the stability of the flow field and further enhancing the effect of attenuating Reynolds stress and optimizing the airflow direction.

[0037] In some embodiments, the cross-sectional area of ​​the serration 5 gradually decreases in the direction away from the blade 2. Specifically, as... Figures 1-5 As shown, the cross-sectional area of ​​the trailing edge serration 5 of blade 2 gradually narrows and smoothly decreases along the direction away from the blade body. This gradually contracting structure can achieve a smooth transition of airflow, effectively weaken the abrupt separation of airflow at the trailing edge of blade 2, evenly disperse the wake vortex, weaken the intensity of trailing edge vortex shedding, avoid local airflow impact and turbulence disturbance, thereby smoothly reducing the aerodynamic noise of the fan, while reducing airflow resistance and further improving the overall flow field characteristics.

[0038] In some embodiments, a plurality of first protrusions 3 and a plurality of second protrusions 4 are spaced apart along the chordal direction of the blade 2, and / or, a plurality of first protrusions 3 and serrations 5 are spaced apart along the chordal direction of the blade 2. Specifically, as Figures 1-5 As shown, the first protrusion 3, the second protrusion 4, and the serration 5 are arranged sequentially along the width direction of the blade 2. By dividing the distribution positions of the first protrusion 3, the second protrusion 4, and the serration 5 in the chord direction, the functional zones of leading edge vortex breaking, pressure surface flow field regulation, and trailing edge wake noise reduction can be clearly defined. While each structure plays its role independently, it forms airflow linkage, realizes full-process flow field optimization, and further improves the overall noise reduction and aerodynamic efficiency of the fan.

[0039] In some embodiments, the height of the sawtooth 5 is greater than or equal to 0.5 mm and less than or equal to 2 mm. Therefore, limiting the height of the sawtooth 5 to the range of 0.5 mm to 2 mm ensures that the sawtooth 5 has sufficient structural dimensions to effectively segment the trailing edge wake and break up vortices, fully exerting its noise reduction effect. It also avoids the problems of increased aerodynamic drag and decreased fan efficiency caused by excessively large sawtooth 5 height, while preventing stress concentration and deformation damage to the slender structure under high-speed operation. This balances structural strength, manufacturability, and overall aerodynamic performance, making it suitable for long-term, harsh operating conditions of mining fans.

[0040] In some embodiments, the serrations 5 can adopt a biomimetic tooth-shaped structure inspired by owl feathers, designed with reference to the natural biological noise reduction characteristics of owl feathers. The two key parameters, the height and spacing of the serrations 5, are distributed in a regular gradient increasing pattern along the spanwise direction of the blade 2 from the leaf root to the leaf tip. Specifically, the serrations 5 are densely arranged at the leaf root, with a height of approximately 0.2 mm and a spacing of approximately 0.8 mm, specifically reducing high-frequency turbulent noise generated under low-speed, high-load conditions. Extending towards the leaf tip along the spanwise direction, a non-uniform gradual arrangement pattern is constructed using the Fibonacci sequence, causing the height and spacing of the serrations 5 to increase progressively until the leaf tip region, where the height of the serrations 5 can reach 3.4 mm and the spacing expands to 13 mm. This biomimetic gradient serration structure creates a stepped sound wave scattering effect at the trailing edge of the blade 2: the densely toothed area at the leaf root effectively scatters 6-10 kHz high-frequency noise, the transitional toothed area in the middle of the blade 2 covers 4-6 kHz mid-frequency noise, and the sparsely toothed area at the leaf tip effectively disperses 3-4 kHz low-frequency eddy radiation noise. Multi-region segmented collaborative coupling achieves integrated suppression of aerodynamic noise across the entire frequency band from 3 to 10 kHz, forming a wide-range continuous noise reduction effect and reducing the overall operating noise of the fan.

[0041] In some embodiments, the mining axial flow fan 100 further includes a motor (not shown in the figure), which is connected to the hub 1 so that the motor drives the hub 1 to rotate. Specifically, as Figures 1-5 As shown, the output shaft of the motor is connected to the hub 1, and the motor drives the hub 1 to rotate, providing a power foundation for the mining axial flow fan 100.

[0042] In some embodiments, the cross-sectional area of ​​the blade 2 gradually decreases in the direction away from the hub 1. As a result, when the wind turbine is working, the linear velocity of the blade 2 at different spanwise positions gradually increases from the blade root to the blade tip. The gradually narrowing cross section can match the airflow load and motion velocity at different positions, making the load distribution of each section of the blade 2 more uniform. Moreover, the gradual decrease in the cross-sectional area of ​​the blade 2 in the direction away from the hub 1 can effectively reduce the aerodynamic drag and centrifugal load at the blade tip, weaken the generation and development of blade tip vortices, delay airflow separation, optimize the overall flow field stability, and reduce aerodynamic noise and energy loss.

[0043] In some embodiments, the blade 2, the first protrusion 3, the second protrusion 4, and the serration 5 are integrally formed. Specifically, the blade 2, the first protrusion 3, the second protrusion 4, and the serration 5 can be integrally cast, injection molded, die-cast, or molded. The leading edge first protrusion 3, the pressure surface second protrusion 4, and the trailing edge serration 5 can be directly and simultaneously machined on the blade 2 blank. Each functional structure and the blade 2 base are made of the same integral material and are formed in one piece without the need for subsequent separate installation, welding, or bonding. This makes the functional structures of the first protrusion 3, the second protrusion 4, and the serration 5 integral with the blade 2 base, eliminating the need for subsequent splicing, welding, or assembly. This not only improves the overall structural strength and rigidity, avoiding problems such as connection gaps, loosening and falling off, and stress concentration, but also withstands high-speed rotating centrifugal loads and complex airflow impacts, adapting to the harsh working environment of mines. It also ensures that the surface of the blade 2 is continuously flat and smooth, eliminating additional eddies and aerodynamic drag caused by splicing gaps, optimizing airflow, reducing aerodynamic noise, simplifying the processing procedures, improving overall dimensional accuracy, and reducing production and maintenance costs.

[0044] 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 orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, 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. Therefore, they should not be construed as limitations on this invention.

[0045] 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.

[0046] 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, an electrical connection, or a connection that allows communication between them; 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.

[0047] 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.

[0048] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the 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.

[0049] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A mining axial flow fan, characterized in that, include: Wheel hub; Multiple blades, all of which are disposed on the hub and spaced apart circumferentially along the hub; Multiple first protrusions are provided on the leading edge of the blade and arranged sequentially along the span of the blade. The first protrusions are used to break up vortices to improve the airflow state. Multiple second protrusions are provided on the pressure surface of the blade and the second protrusions are arranged at intervals along the spanwise direction of the blade. The second protrusions are used to suppress turbulent pulsation on the pressure surface of the blade and attenuate Reynolds stress. Multiple serrations are provided on the trailing edge of the blade and arranged sequentially along the span of the blade. The multiple serrations are used to reduce blade operating noise.

2. The mining axial flow fan according to claim 1, characterized in that, The cross-sectional area of ​​the first protrusion gradually decreases in the direction away from the blade, and the top of the first protrusion is arc-shaped.

3. The mining axial flow fan according to claim 1, characterized in that, The second protrusion extends along the chordal direction of the blade, and an airflow channel is defined between two adjacent second protrusions.

4. The mining axial flow fan according to claim 1, characterized in that, The cross-sectional area of ​​the second protrusion is triangular or rectangular.

5. The mining axial flow fan according to claim 1, characterized in that, The cross-sectional area of ​​the serrations gradually decreases in the direction away from the blade.

6. The mining axial flow fan according to claim 1, characterized in that, The plurality of first protrusions and the plurality of second protrusions are spaced apart along the chordal direction of the blade, and / or the plurality of first protrusions and the serrations are spaced apart along the chordal direction of the blade.

7. The mining axial flow fan according to claim 1, characterized in that, The height of the saw teeth is greater than or equal to 0.5 mm and less than or equal to 2 mm.

8. The mining axial flow fan according to claim 1, characterized in that, It also includes a motor connected to the wheel hub so that the motor drives the wheel hub to rotate.

9. The mining axial flow fan according to claim 1, characterized in that, The cross-sectional area of ​​the blade gradually decreases in the direction away from the hub.

10. The mining axial flow fan according to claim 1, characterized in that, The blade, the first protrusion, the second protrusion, and the serrations are integrally formed.

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