Fan module

Abstract

The fan module comprises an air duct, an impeller and a driving unit, an air inlet and an air outlet are formed in the air duct in the axial direction, a flow guide partition plate is arranged at the air outlet, and the impeller comprises a hub and a plurality of fan blades arranged on the circumferential end face of the hub in an annular array mode. The impeller is arranged at the middle section position of the air duct, the flow guide partition plate is in clearance fit with the fan blades, the flow guide partition plate is obliquely arranged relative to the axial direction of the air duct and is bent automatically, and the windward end of the flow guide partition plate is of a blade-shaped structure. The included angle between the chord line of the section, from the root to the tip end, of each fan blade and the rotating plane changes continuously, so that the fan blades are in a spatial twisted shape, the rotating motion trails of the tip ends of the fan blades are uniform in the axial direction of the air flue, and the tip ends of the fan blades are in clearance fit with the inner wall of the head shell. The fan has the advantages of ensuring stable acceleration of airflow, improving the output air volume, increasing the air supply distance and reducing noise.

Description

Technical Field

[0001] This invention relates to the field of fan technology, and more particularly to a fan module. Background Technology

[0002] Current fan modules are limited by traditional structural design and manufacturing processes in terms of aerodynamic performance and noise control. On the one hand, to balance structural strength and processing convenience, the air outlet guide grille generally adopts a blunt-head configuration, which leads to severe flow separation and periodic vortex shedding when the airflow passes through. This not only causes airflow energy loss and wind pressure attenuation, but also generates significant broadband airflow noise. On the other hand, cost control constraints result in dimensional and positional tolerances between the impeller and the casing, and between the impeller and the guide baffle. During operation, the leakage flow from the high-pressure area to the low-pressure area not only causes energy loss, but also interacts with the main airflow to generate unstable vortices, resulting in reduced airflow efficiency and increased turbulence noise. This limits the performance of the fan module in terms of output air volume, air delivery distance, and noise reduction. Summary of the Invention

[0003] To address the shortcomings of existing technologies, a fan module is provided.

[0004] The present invention is implemented using the following technical solutions:

[0005] A fan module includes an air duct formed by the inner wall of a head housing, an impeller coaxially disposed within the air duct, and a drive unit for driving the impeller. The air duct has an air inlet and an air outlet in its axial direction. The front end of the impeller corresponds to the air inlet, and the rear end corresponds to the air outlet. A baffle is provided at the air outlet. The impeller includes a hub and a plurality of fan blades arranged in a ring array on the circumferential end face of the hub. The impeller is located in the middle section of the air duct. The baffle and the fan blades are in clearance fit. The baffle is inclined relative to the axial direction of the air duct and is self-bending. The windward end of the baffle has a blade-shaped structure. The angle between the chord line of the cross section of the fan blade from the root to the tip and the plane of rotation changes continuously, so that the fan blade is spatially twisted. The rotation trajectory of the tip of the fan blade is uniform along the axial direction of the air duct. The tip of the fan blade is in clearance fit with the inner wall of the head housing.

[0006] The drive unit can be a wire used to drive the impeller to rotate or other existing technology structures that provide power to the impeller.

[0007] By gradually twisting the fan blades along their height, the angle between the blade tip and the root gradually increases, ensuring a relative balance in the radial pressure distribution of the airflow. This weakens the pressure difference driving force between the blade tip and the inner wall of the head housing, suppressing backflow leakage of high-pressure airflow to low-pressure areas. Compared to traditional fan modules, this avoids leakage flow and aerodynamic noise caused by manufacturing tolerances. Furthermore, by using a more precise and narrower gap than existing technologies, the airflow at that location is reduced, increasing the obstruction to airflow backflow. Consequently, at the same rotational speed, more air is effectively pushed from the inlet to the outlet, thereby increasing the actual output air volume.

[0008] During the process of airflow from the air inlet to the air outlet, the rotating airflow blown out by the impeller is segmented and rectified by the baffle plate located at the air outlet. The blade-shaped front end splits the incoming airflow, allowing the airflow to flow close to the edge. Compared with the existing blunt or square front end, this can avoid periodic vortex shedding, effectively reduce aerodynamic drag and reduce the resulting broadband noise, thereby achieving higher speed and airflow at the same power consumption.

[0009] Preferably, the angle between the tangent of the baffle near the air inlet and the axis of the air duct does not exceed 5°. The baffle includes a parallel section near the air outlet and a curved section between the parallel section and the impeller. The axial length ratio of the curved section to the parallel section is 1:1.5 to 1:2.

[0010] The curved section can utilize the Coanda effect to turn the airflow from tangential to axial, while the parallel section can stabilize the flow field, eliminate internal turbulence, and achieve airflow homogenization. This ratio ensures that the curved section has sufficient length to complete the main turning task, while the parallel section has more sufficient length to stabilize the flow field and homogenize the velocity distribution.

[0011] Preferably, the blade angle at the windward end of the baffle is 20° to 25°, thereby achieving smooth airflow diversion.

[0012] Preferably, the number of fan blades is greater than 5, and the number of flow guide baffles is greater than the number of fan blades and coprime to the number of fan blades. This ensures that when the impeller rotates, the periodic pulsations generated when any impeller passes over the flow guide baffles will not be synchronously superimposed, thereby achieving the purpose of eliminating resonance noise.

[0013] Preferably, the windward end of the hub has a bullet-shaped structure, and the length of the leading edge of the fan blade is greater than the length of the trailing edge so that the distance between the tip of the fan blade and the axis of the head housing is equal at all axial positions, and the linear velocity of the tip of the fan blade is the same at all axial positions.

[0014] By designing the outer surface shape of the hub, frontal air resistance is reduced, and the air duct at the radial direction of the hub gradually narrows from the air inlet to the air outlet, thereby concentrating air pressure. Furthermore, by setting the shape of the fan blades, which, when unfolded, form a trapezoidal shape that is narrower at the front and wider at the back along the axial direction, the air-skimming area is increased, ensuring that the linear velocity at all positions of the blade tip remains at the highest possible level. This allows the airflow to be accelerated smoothly and evenly, reducing vortices and flow separation inside the impeller, thereby improving the efficiency of working on the air.

[0015] Preferably, the width of the gap between the tip of the fan blade and the inner wall of the head housing does not exceed 1 mm.

[0016] Compared to traditional fan modules, by limiting the gap between the tip and the inner wall of the head housing, a high-strength shear layer is formed on the rotation path of the tip when the impeller rotates at high speed. This makes it difficult for vortices to mix in, thereby suppressing the backflow leakage of airflow from the high-pressure area to the low-pressure area and forcing the airflow to be guided and transmitted along the curved surface of the blade.

[0017] Preferably, the distance H between the leading edge and the air inlet is 13mm-20mm, the axial length of the baffle is h, the ratio of H to h is 1:1 to 1:1.3, and the axial distance between the baffle and the fan blade is 1mm-4mm.

[0018] After the airflow passes through the air inlet, there is enough distance for the turbulent incoming flow to become stable and flow to the fan blades. This avoids the fan blades experiencing force fluctuations due to uneven air intake, reduces the generation of airflow separation noise and rotational stall noise, and by limiting the axial distance between the guide baffle and the fan blades, the rectification channel of the airflow entering the guide baffle after leaving the blade tip is shortened, preventing the airflow from spreading and generating eddies in this axial gap, which would affect the rectification effect and generate eddy noise.

[0019] Preferably, the leading edge includes a first edge and a second edge that are relatively deflected, and the angle between the first edge and the second edge is an obtuse angle. This allows the blades to maintain high efficiency even at a larger intake angle of attack, thereby widening the efficient operating range of the fan. Compared to a circular or pointed leading edge, this design allows the airflow to adhere to both sides of the blades earlier and more stably while reducing the resistance caused by airflow impact. This improves efficiency and operational stability, and avoids the phenomenon where the airflow cannot adhere to the blade surface and separates, resulting in a sudden drop in lift and a surge in drag.

[0020] Preferably, the air duct is tapered from the air inlet to the air outlet, and the tapering slope at the air outlet of the head housing is greater than the tapering slope at the body and the air inlet of the head housing.

[0021] Because the air duct narrows from the inlet to the outlet, it forms a gradually narrowing air duct structure, which facilitates the conversion of static pressure gained by the airflow at the impeller into dynamic pressure, thereby increasing the airflow velocity. The design of being gentle at the beginning and steep at the end ensures that the airflow remains attached throughout the acceleration process, avoiding flow separation, suppressing the generation of broadband turbulence noise, and converting the static pressure of the airflow into dynamic pressure in the shortest axial distance, so that the airflow at the outlet can obtain higher velocity and kinetic energy.

[0022] Preferably, a cooling mechanism is provided at the center of the air outlet of the head housing. The cooling mechanism is concentrically arranged with the head housing and has an outer circumferential surface concentrically arranged with the head housing. The distance between the cooling mechanism and the inner wall of the head housing is 6mm-8mm, thereby ensuring that the annular airflow channel formed by the inner wall of the head housing and the outer circumferential surface of the cooling mechanism has sufficient cross-sectional area.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The blade-shaped structure of the baffle smoothly cuts into the airflow, achieving active splitting and rectification of the rotating airflow. This avoids the flow separation phenomenon caused by traditional blunt-nosed structures, effectively suppresses vortex shedding, thereby reducing broadband noise and kinetic energy loss. The tangential momentum is then efficiently converted into axial kinetic energy through the curved section. Based on the Coanda effect, the airflow flows closely along the curved surface, significantly improving airflow concentration and enhancing the delivery distance.

[0025] By using a twisted design where the fan blades gradually twist along the blade height, the dynamic balance of airflow in radial pressure distribution is ensured, the pressure difference driving force between the fan blade tip and the casing wall is weakened, and backflow leakage from the high-pressure area to the low-pressure area is effectively suppressed, thereby reducing leakage flow loss caused by manufacturing tolerances. Combined with the gradually narrowing air duct structure, the static pressure of the airflow is continuously converted into dynamic pressure, thereby accelerating the airflow.

[0026] The arrangement of fan blades and baffles of similar numbers ensures that the periodic pulsations generated when any impeller passes over a baffle during impeller rotation do not overlap synchronously. This results in asynchronous distribution of periodic pressure pulsations, eliminating resonance noise, ensuring smooth airflow acceleration, significantly improving aerodynamic efficiency, and enhancing the performance of the fan module. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of a fan module according to the present invention;

[0028] Figure 2 This is a schematic diagram of the structure at another axial angle of the present invention;

[0029] Figure 3 This is a radial cross-sectional view of the present invention;

[0030] Figure 4 for Figure 3 Enlarged structural diagram at point A;

[0031] Figure 5 for Figure 3 A schematic diagram of the cross-sectional structure along the BB direction;

[0032] Figure 6 This is an axial sectional view of the present invention;

[0033] Figure 7 for Figure 6 A schematic diagram of the structure under the current conditions;

[0034] Figure 8 This is a three-dimensional sectional view of the present invention in a radial section reference state;

[0035] Figure 9 This is a schematic diagram of the impeller structure in this invention.

[0036] Reference numerals: 1. Head casing; 2. Impeller; 3. Baffle plate; 4. Refrigeration mechanism; 11. Air duct; 111. Air inlet; 121. Air outlet; 1211. Assembly ring; 21. Hub; 22. Fan blade; 221. Tip; 222. Root; 223. Leading edge; 2231. First edge; 2232. Second edge; 224. Trailing edge; 31. Windward end; 32. Parallel section; 33. Curved section. Detailed Implementation

[0037] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0038] like Figure 1 — Figure 9 As shown, this embodiment discloses a fan module, including an air duct 11 formed by the inner wall of the head housing 1, an impeller 2 coaxially disposed in the air duct 11, and a drive unit (not shown in the figure) for driving the impeller 2. The two axial ends of the air duct 11 respectively form an air inlet 111 and an air outlet 121. The impeller 2 is disposed in the middle section of the air duct 11, with its axial front end corresponding to the air inlet 111 and its axial rear end corresponding to the air outlet 121. The drive unit can be any existing wire used to drive the impeller 2 to rotate or other existing technical structures that provide power to the impeller 2.

[0039] The air duct 11 is tapered from the air inlet 111 to the air outlet 121, forming a gradually narrowing air duct structure. An assembly ring 1211 is fixed at the air outlet 121. The inner ring surface of the assembly ring 1211 is a sloping end located at the air outlet 121 with a taper of θ1. The head shell 1 also has a corresponding slope with a taper of θ2. θ1 is greater than θ2, thus forming an accelerating air duct structure that is first gentle and then steep. This ensures that the airflow remains attached and flows throughout the acceleration process and can efficiently convert static pressure into dynamic pressure, allowing the outlet airflow to obtain a higher speed. The kinetic energy conversion is completed within a short axial distance formed by the steeper contraction slope at the outlet.

[0040] A cooling mechanism 4 can also be provided at the center of the air outlet 121 of the head housing 1. The cooling mechanism 4 has the same structure as the existing semiconductor cooling chip. The cooling mechanism 4 is concentrically arranged with the head housing 1, and its outer circumferential surface is kept 6mm to 8mm away from the inner wall of the head housing 1 to form an annular air outlet channel with sufficient flow cross-sectional area to ensure that the cooling airflow passes smoothly and effectively exchanges heat with the cold end of the cooling mechanism 4.

[0041] The impeller 2 includes a hub 21 and several fan blades 22 arranged in an annular array on the circumferential end face of the hub 21. The angle between the chord line of the cross section of the fan blade 22 from its root 222 to its tip 221 and the plane of rotation changes continuously, making the fan blade 22 spatially twisted. This ensures the relative balance of airflow in the radial pressure distribution of the fan blade 22, effectively weakening the pressure difference driving force between the tip 221 of the fan blade 22 and the inner wall of the head housing 1, thereby suppressing the backflow leakage of high-pressure airflow to the low-pressure area. The rotational trajectory of the tip 221 of the fan blade 22 is uniform along the axial direction of the air duct 11, and there is a small radial gap α between the tip 221 and the inner wall of the head housing 1, which is 0.5 mm.

[0042] When the impeller 2 rotates at high speed, the radial gap α between the tip 221 and the inner wall of the head housing 1 is only 0.5mm, which forms a high-strength shear layer on the path of the tip 221, further hindering airflow leakage and forcing the airflow to do work effectively along the curved surface of the fan blade 22, thereby increasing the actual output air volume at the same speed.

[0043] The windward end of the hub 21 has a bullet-shaped structure, which helps to reduce frontal air resistance and makes the radial air duct 11 of the hub 21 taper, which is conducive to the concentration of wind pressure. The leading edge 223 of the fan blade 22 is longer than the trailing edge 224, so that it is trapezoidal when unfolded, which increases the effective wind sweep area and ensures that the distance between each point of the tip 221 of the fan blade and the axis of the head shell 1 is equal and the linear velocity is similar, thereby achieving smooth and uniform acceleration of the airflow and weakening internal vortices and flow separation.

[0044] The leading edge 223 includes a first edge 2231 and a second edge 2232 that are relatively deflected. The angle between the first edge 2231 and the second edge 2232 is an obtuse angle and is transitioned through a rounded edge, thereby increasing the angle of attack range in which the airflow can stably adhere, so that the fan can maintain its operating performance from startup to high load.

[0045] A baffle plate 3 is provided at the air outlet 121. The baffle plate 3 is inclined relative to the axial direction of the air duct 11 and is curved. Its windward end 31 has a blade-shaped structure with a blade angle of 20° to 25°. The windward end 31 can smoothly split the airflow and make it flow closely along the surface of the baffle plate, avoiding the periodic vortex shedding caused by the traditional blunt head structure, effectively reducing aerodynamic drag and reducing broadband noise.

[0046] The baffle 3 includes a parallel section 32 near the air outlet 121 and a curved section 33 located between the parallel section 32 and the impeller 2. The curvature direction of the curved section 33 is opposite to that of the fan blade 22, which is used to actively counteract the rotational momentum of the airflow. The end of the curved section 33 is the windward end 31 of the baffle 3. The curved section 33 can use the Coanda effect to convert the tangential momentum of the airflow into axial momentum, while the parallel section 32 is used to stabilize the flow field and eliminate turbulence. The axial length ratio of the curved section 33 to the parallel section 32 is 1:1.5 to 1:2 to ensure sufficient deflection and flow field stability. The angle between the tangent of the baffle 3 near the air inlet 111 and the axis of the duct 11 does not exceed 5° to optimize the air intake conditions. The axial distance between the baffle 3 and the fan blade 22 is 1mm to 4mm, which avoids the airflow from spreading and generating vortices after leaving the impeller and ensures the rectification effect.

[0047] There are 7 fan blades 22 and 8 baffles 3. The number of baffles 3 is greater than the number of fan blades 22, and the two are coprime. This ensures that when the impeller 2 rotates, the periodic pressure pulsations generated by any fan blade 22 passing over the baffle 3 will not be synchronously superimposed, thereby achieving the purpose of eliminating resonance noise.

[0048] The distance H between the foremost point of the leading edge 223 of the fan blade 22 and the air inlet 111 is 14mm. Correspondingly, the axial length h of the guide baffle 3 is also set to 14mm. This ensures that the airflow has a sufficient stable section after entering the air inlet 111, so that the turbulent incoming flow tends to be stable before reaching the fan blade 22. This effectively avoids the force fluctuation of the fan blade 22 caused by uneven air intake, thereby reducing the generation of airflow separation noise and rotational stall noise.

[0049] Actual measurements showed that the wind speed at 5cm from the air outlet 121 in this embodiment was 12.8m / s, while the wind speed at 5cm from the air outlet 121 of a traditional high-speed fan was 7.7m / s; the noise level detected by the handheld noise meter at 30cm from the air outlet 121 in this embodiment was 73.2dB, while that of the traditional high-speed fan was 72.8dB.

Claims

1. A fan module comprising a wind channel enclosed by an inner wall of a head shell, an impeller coaxially arranged in the wind channel, and a driving unit driving the impeller, the wind channel having an air inlet and an air outlet in axial direction respectively, the axial front end of the impeller corresponding to the air inlet, and the axial rear end corresponding to the air outlet, a flow guide partition plate being arranged at the air outlet, the impeller comprising a hub and a plurality of fan blades arranged in an annular array on the circumferential end surface of the hub, characterized in that: The impeller is arranged at a middle section of the air duct, the guide baffle is arranged in gap cooperation with the fan blades, the guide baffle is arranged in an inclined manner relative to the axial direction of the air duct and is curved, the windward end of the guide baffle is in a blade shape, the angle between the chord line of the fan blade from the root to the tip and the rotation plane continuously changes, so that the fan blade is in a spatially twisted shape, the movement track of the tip of the fan blade is uniform along the axial direction of the air duct, and the tip of the fan blade is in gap cooperation with the inner wall of the head shell.

2. The fan module of claim 1, wherein: The angle between the tangent line of the end of the guide baffle close to the air inlet and the axis of the air duct is not more than 5°, the guide baffle comprises a parallel section close to the air outlet and a curved section between the parallel section and the impeller, and the length ratio of the curved section to the parallel section in the axial direction is 1:1.5 to 1:

2.

3. The fan module of claim 2, wherein: The included angle of the blade edge of the windward end of the guide baffle is 20° to 25°.

4. The fan module of claim 3, wherein: The number of the fan blades is greater than 5, and the number of the guide baffles is greater than the number of the fan blades and is co-prime to the number of the fan blades.

5. A fan module according to claim 1 or 2 or 3 or 4, wherein: The windward end of the hub is in a bullet head shape, the length of the leading edge of the fan blade is greater than the length of the trailing edge, so that the tip of the fan blade has equal spacing from the axis of the head shell at each axial position, and the linear speed of the tip of the fan blade is the same at each axial position.

6. The fan module of claim 5, wherein: The gap between the tip of the fan blade and the inner wall of the head shell is not more than 1mm in width.

7. The fan module of claim 6, wherein: The spacing H between the leading edge and the air inlet is 13mm-20mm, the axial length of the guide baffle is h, and the ratio of H to h is 1:1 to 1:1.3, and the axial spacing between the guide baffle and the fan blade is 1mm-4mm.

8. The fan module of claim 7, wherein: The leading edge comprises a first edge and a second edge that are relatively deflected, and the included angle between the first edge and the second edge is obtuse.

9. The fan module of claim 8, wherein: The air duct is tapered from the air inlet to the air outlet, and the tapering slope of the air outlet of the head shell is greater than the tapering slopes of the barrel and the air inlet of the head shell.

10. The fan module of claim 9, wherein: The air outlet of the head shell is provided with a refrigeration mechanism at the axis, the refrigeration mechanism is arranged concentrically with the head shell, the refrigeration mechanism has an outer circumferential surface arranged concentrically with the head shell, and the distance between the outer circumferential surface of the refrigeration mechanism and the inner wall of the head shell is 6mm-8mm.

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