Impeller, fan and dust collector

Abstract

The present application relates to the field of fluid machinery, and discloses an impeller, a fan and a dust collector, comprising a hub and blades, the blades are multiple, the multiple blades are distributed and arranged on the circumference of the hub, and the area between each two adjacent blades forms a flow channel; a groove is arranged on the surface of the impeller, the groove comprises a long groove and a short groove, and the long groove and the short groove are alternately arranged. By arranging the groove on the surface of the impeller, the vortex can be lifted above the ridge of the groove, the contact area between the vortex and the surface of the impeller is reduced, the energy loss caused by the contact between the vortex and the surface of the impeller is reduced, the vortex can move along the groove after being lifted, the energy loss caused by the transverse diffusion and development of the vortex is reduced, the fluid flow resistance is reduced, and the performance of the impeller is improved. Moreover, compared with arranging only one kind of groove on the surface of the impeller, since the surface of the impeller is usually irregular or non-uniform, the combination of the long groove and the short groove can be more suitable for the shape of the impeller, and the drag reduction effect is ensured.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery, and in particular to an impeller, a fan, and a vacuum cleaner. Background Technology

[0002] A vacuum cleaner's fan drives an impeller to rotate at high speed using a motor, creating a high negative pressure space within a sealed cavity. This draws external dust into the dust collection device, thus achieving the purpose of cleaning.

[0003] Currently, vacuum cleaner fans rotate at speeds ranging from 20,000 to 150,000 rpm, achieving a total aerodynamic power of 120-230 AW. The impeller, as a key component of the vacuum cleaner fan, directly determines the overall aerodynamic power and efficiency of the unit. However, current impellers exhibit relatively poor aerodynamic performance. Utility Model Content

[0004] The present invention aims to provide an impeller, a fan, and a vacuum cleaner, wherein the impeller has superior aerodynamic performance.

[0005] The present invention addresses its technical problems by adopting the following technical solution: providing an impeller, including a hub and blades, wherein there are multiple blades, which are distributed in the circumferential direction of the hub, and a flow channel is formed in the area between each pair of adjacent blades; grooves are formed on the surface of the impeller, the grooves including long grooves and short grooves, which are alternately arranged.

[0006] In some embodiments, the groove is formed on the surface of the wheel hub.

[0007] In some embodiments, the radius of the wheel hub increases from the front to the rear, the long groove extends from the front to the rear of the wheel hub, and the short groove extends from the middle to the rear of the wheel hub.

[0008] In some embodiments, the grooves are formed on the surface of the blade.

[0009] In some embodiments, the blade includes a pressure surface and a suction surface, and the groove is provided on the pressure surface and / or the suction surface. The pressure surface is the side of the blade facing the rotation direction of the impeller, and the suction surface is the side of the blade away from the rotation direction of the impeller.

[0010] In some embodiments, the blade height decreases from the front to the rear of the blade, the long groove extends from the rear of the blade to the front of the blade, and the short groove extends from the middle of the blade to the front of the blade.

[0011] In some embodiments, the number of long trenches is equal to the number of short trenches; or, the number of long trenches differs from the number of short trenches by 1.

[0012] In some embodiments, the ratio of the length of the short trench to the length of the long trench is 0.3 to 0.5.

[0013] In some embodiments, the total width of the grooves within a single flow channel accounts for 20% to 50% of the total circumference of the outlet of a single flow channel.

[0014] In some embodiments, 10 ≤ the number of grooves n between each pair of adjacent blades ≤ 20.

[0015] In some embodiments, the surface of the middle section of the hub is concave inward toward the axis of the hub, the surface of the rear section of the hub is convex outward toward the axis of the hub, and the groove has a triangular cross-section.

[0016] In some embodiments, the angle between the extending direction of the surface at the rear periphery of the hub and the axial direction of the hub is 0° to 50°.

[0017] The present invention also employs the following technical solution to solve its technical problem: providing a fan, including the impeller as described above.

[0018] The present invention also employs the following technical solution to solve its technical problem: a vacuum cleaner, including the fan described above.

[0019] Compared with existing technologies, in the impeller, fan, and vacuum cleaner provided in the embodiments of the present invention, by creating grooves on the surface of the impeller, vortices can be lifted onto the ridges of the grooves, reducing the surface contact area between the vortex and the impeller, and reducing the energy loss caused by the surface contact between the vortex and the impeller. After being lifted, the vortex can move along the grooves, reducing the energy loss caused by the lateral diffusion and development of the vortex, reducing fluid flow resistance, and improving impeller performance. Furthermore, compared to setting only one type of groove on the surface of the impeller, since the surface of the impeller is usually irregular or non-uniform, the combination of long and short grooves can better adapt to the shape of the impeller and ensure drag reduction effect. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0021] Figure 1 This is a schematic diagram of the triangular grooved ribs on the skin of a shark.

[0022] Figure 2This is a schematic diagram of the structure of an impeller provided in Embodiment 1 of the present invention;

[0023] Figure 3 yes Figure 2 The diagram shows the structure of the impeller at another angle;

[0024] Figure 4 This is a schematic diagram of the vortex and impeller surface without grooves.

[0025] Figure 5 This is a schematic diagram of the vortex and impeller surface after the grooves are set;

[0026] Figure 6 yes Figure 2 A schematic diagram of the impeller groove structure is shown;

[0027] Figure 7 This is a schematic diagram of the impeller structure provided in Embodiment 2 of the present invention;

[0028] Figure 8 yes Figure 7 The diagram shows the structure of the impeller at another angle. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as "connected" to another element, it can be directly on the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "left," "right," "upper end," "lower end," "top," and "bottom," etc., used in this specification indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0031] Sharks are among the fastest swimming animals in the ocean. Numerous experiments and studies have shown that, compared to other smooth structures, sharkskin-like structures (triangular grooved ribs) possess superior drag-reduction and anti-adhesion properties. The scales on the surface of sharkskin are shaped like... Figure 1 As shown.

[0032] The sharkskin-inspired (triangular grooved rib) structure reduces viscosity and drag using vortex drag reduction theory. Turbulent flow generates numerous vortices, and the contact between these vortices and the structural surface results in energy loss, increasing drag. Furthermore, vortex diffusion generates secondary vortices, similarly increasing drag. The grooves created on the structural surface lift these vortices, causing them to remain above the groove ridges. This reduces the velocity gradient and velocity pulse within the grooves to a level lower than the velocity gradient and velocity pulse on the structural surface, thus lowering the shear stress between the airflow and the surface. Simultaneously, the grooves guide the vortex structure along the grooves, preventing lateral vortex migration and reducing vortex bursting, entanglement, and turbulence outside the boundary layer.

[0033] The groove dimensions of the sharkskin-like (triangular grooved rib) structure need to be strictly limited. When the vortex structure is smaller than the groove, it will fall into the groove and interact with the groove surface. When the vortex size is larger than the groove structure, the vortex is lifted, reducing the contact area with the groove surface and thus reducing the interaction. Simultaneously, the surface area of ​​the groove is larger than that of a plane. Therefore, only when the groove width and spacing are sufficiently small to avoid frictional resistance being smaller than that of a smooth plane can a drag-reduction effect be observed. The depth-to-width ratio of the groove, i.e., the ratio of the groove depth to its width, is related to both the groove depth and width. A small depth-to-width ratio results in a large groove width, making it easier for vortices to fall into the groove and interact with the groove surface; a large depth-to-width ratio results in a small groove width, making it difficult for vortices to fall into the groove, reducing contact with the groove surface and thus reducing the interaction. Therefore, only when the depth-to-width ratio is appropriate and the wall frictional resistance is smaller than that of a smooth plane can a drag-reduction effect be observed.

[0034] Example 1

[0035] Inspired by the above, Embodiment 1 of the present invention provides an impeller, which can be either a semi-open impeller or a closed impeller. Generally, a closed impeller includes a disc, a cover, and multiple blades, with the disc and cover arranged opposite to each other, and the multiple blades disposed between the disc and cover. Compared to a closed impeller, a semi-open impeller does not have a cover. In this embodiment, a semi-open impeller is used as an example for explanation.

[0036] It is worth noting that the large opening and low strength of the end cap of a closed impeller limit the increase in circumferential speed and motor efficiency. In contrast, a semi-open impeller, without the limitation of an end cap, allows for a significantly higher maximum permissible circumferential speed. Therefore, using a semi-open impeller can achieve higher rotational speeds and higher aerodynamic efficiency.

[0037] Please see Figure 2 and Figure 3 The impeller includes a hub 10 and multiple blades 20. The multiple blades 20 are distributed circumferentially along the hub 10 in a circular array, and the hub 10 is located at the center of the circular array. The spacing between each pair of adjacent blades 20 is equal.

[0038] The hub 10 is generally conical or frustum-shaped. Along the axial direction of the hub 10, it can be divided into a front section, a middle section, and a rear section, with the middle section located between the front and rear sections. In the direction from the front section to the rear section, the diameter of the hub 10 increases; that is, the diameter of the front section is smaller, and the diameter of the rear section is larger. Specifically, in the direction from the front section to the rear section, the rate of increase in the diameter of the hub 10 first increases and then decreases, so that the surfaces of the front and middle sections are concave towards the axis of the hub 10, while the surface of the rear section is convex away from the axis of the hub 10.

[0039] The extension direction of the surface at the rear periphery of the hub 10 tends to be parallel to the axis of the hub 10. The rear periphery of the hub 10 is the periphery of the end of the rear section of the hub 10 that is away from the front section of the hub 10.

[0040] The rear section of hub 10 forms a semi-open impeller disc.

[0041] The impeller has an air inlet and an air outlet. The air inlet is located near the front section of the hub 10, and the air outlet is located near the rear section of the hub 10.

[0042] The blades 20 extend along a helix, which may have fewer than one turn. The center line of the helix along which the blades 20 extend coincides with the axis of the hub 10, and the helical direction of the helix along which each blade 20 extends is consistent.

[0043] A flow channel is formed between every two adjacent blades 20. One end of the flow channel connects to the impeller's inlet, and the other end connects to the impeller's outlet. During impeller rotation, fluid flows into the flow channel from the inlet, flows along the flow channel, and then flows out of the flow channel from the outlet. The direction of the flow channel from the inlet to the outlet is the flow direction, and the width of the flow channel tends to increase along the flow direction.

[0044] The number of blades 20 is N, where 7 ≤ N ≤ 11. The specific number of blades 20 can be determined based on the overall aerodynamic performance required by the impeller.

[0045] Each blade 20 includes a leading edge surface 21, a trailing edge surface 22, a tip surface 23, a root surface 24, a pressure surface 25, and a suction surface 26. The side of the blade 20 facing the impeller rotation direction is the pressure surface 25, and the side of the blade 20 away from the impeller rotation direction is the suction surface 26. The four edges of the blade 20 form the leading edge surface 21, trailing edge surface 22, tip surface 23, and root surface 24, respectively. Specifically, the leading edge surface 21, trailing edge surface 22, tip surface 23, and root surface 24 are all located between the pressure surface 25 and the suction surface 26. The leading edge surface 21 is close to the impeller's air inlet, and forms an angle with the axis of the hub 10. The end of the leading edge surface 21 away from the axis of the hub 10 is higher than the end of the leading edge surface 21 close to the axis of the hub 10. This arrangement is mainly to reduce the airflow resistance at the leading edge of the blade during impeller rotation. The trailing edge surface 22 is close to the air outlet of the impeller, and the end of the trailing edge surface 22 near the axis of the hub 10 is higher than the other end of the trailing edge surface 22 away from the axis of the hub 10. The end of the blade tip surface 23 near the air inlet is connected to one end of the leading edge surface 21, specifically the end of the leading edge surface 21 away from the axis of the hub 10; the end of the blade tip surface 23 near the air outlet is connected to one end of the trailing edge surface 22, specifically the end of the trailing edge surface 22 near the axis of the hub 10. The blade root surface 24 is in contact with the surface of the hub 10 to form an integral structure. The end of the blade root surface 24 near the air inlet is connected to one end of the leading edge surface 21, specifically the end of the leading edge surface 21 near the axis of the hub 10; the end of the blade root surface 24 near the air outlet is connected to one end of the trailing edge surface 22, specifically the end of the trailing edge surface 22 near the peripheral edge of the tail end of the hub 10.

[0046] The extension direction of the surface of the hub 10 near the trailing edge surface 22 of the blade 20, i.e., the extension direction of the surface at the peripheral edge of the trailing end of the hub 10, forms an angle of 0 to 50° with the axial direction of the hub 10. This design allows the peripheral edge of the trailing end of the hub 10 to act as a guide, directing the fluid to an angle of 0 to 50° with the axial direction of the hub 10. This reduces energy loss caused by the collision between the fluid and the inner wall of the fan casing. The junction between the blade tip surface 23 and the trailing edge surface 22 of the blade 10 has a rounded, smooth transition, which effectively guides the fluid flowing through the blade 10 to a direction substantially parallel to the axial direction of the hub 10. This reduces collision losses between the fluid at the outlet of the trailing edge surface 22 of the blade 20 and the inner wall of the fan casing, improving the impeller's performance. The airflow enters the impeller axially and exits the impeller axially. This type of impeller can be used in vacuum cleaner fans.

[0047] Along the extension direction of blade 20, that is, along the helical direction, blade 20 can be divided into a front section and a rear section. The front section of blade 20 is closer to the impeller's inlet, and the rear section is closer to the impeller's outlet. The pressure surface 25 of the front section of blade 20 is concave, forming a concave surface; specifically, the direction of concavity is opposite to the impeller's rotation direction. The pressure surface 25 of the rear section of blade 20 is convex, forming a convex surface; specifically, the direction of convexity is the same as the impeller's rotation direction. The front and rear sections of blade 20 transition smoothly.

[0048] After installation, gaps inevitably form between the impeller and the inner wall of the fan casing. When the impeller rotates, a pressure difference is created between the flow channel and this gap. Part of the airflow within the flow channel leaks through the blade tip surface 23 towards the gap. In other words, fluid leakage occurs at the blade tip surface 23 of the blade 20, leading to reduced impeller performance. Furthermore, when leakage occurs at the blade tip or even the inlet, the effective work-performing fluid flow rate decreases, and the pressure generated by the fluid passing through the blade decreases, easily causing impeller performance degradation. Therefore, the impact of leakage at the blade tip is more pronounced. By setting the pressure surface 25 at the blade tip to be concave in the opposite direction to the impeller's rotation, it facilitates fluid flow guidance. Moreover, the pressure surface at the blade tip can envelop the fluid at the inlet, reducing leakage losses at the inlet, increasing the impeller's pressure surface at low flow rates, increasing the contact area between the pressure surface and the fluid, and improving impeller performance.

[0049] The pressure surface 25 under low flow conditions is described in detail here. When the impeller is in operation at low flow, the fluid cannot fill the entire flow channel, and boundary layer separation will occur at the pressure surface 25 of the blade 20, that is, flow separation. By setting the pressure surface 25 of the blade 20 to be concave inward and convex outward, the fluid can be guided to approach the surface of the hub 10 and the pressure surface 25 and suction surface 26 of the blade 20, reducing the flow loss of the fluid near the blade tip surface 23.

[0050] The curvature of the front section of blade 20 is less than the curvature of the rear section of blade 20.

[0051] A detailed explanation of concave and convex surfaces is required here; please refer to [link / reference]. Figure 2Four points M, Q, N, and P are taken on the blade 20. M and Q are two points on the blade 20 closest to the root surface 24, and N and P are two points on the blade 20 closest to the tip surface 23. The line connecting MN is located in the front section of the blade 20, and the line connecting P and Q is located in the rear section of the blade 20. Each part of the front section of the blade 20 has the following characteristics: the projection of the line connecting MN onto the pressure surface 25 or suction surface 26 of the blade 20 is approximately an arc, and its convex direction is opposite to the rotation direction of the impeller. Each part of the tail section of blade 20 has the following characteristics: the projection of the PQ line onto the pressure surface 25 or suction surface 26 of blade 20 is approximately an arc or a straight line, and its curvature is much greater than the curvature of the projection of the MN line onto the pressure surface 25 or suction surface 26 of blade 20; the projection of the PQ line onto the tail section of blade 20 near the trailing edge surface 22 is approximately a straight line, and the projection onto the tail section of blade 20 away from the trailing edge surface 22 is approximately an arc; the convex direction of the projection of the PQ line onto the pressure surface 25 or suction surface 26 of blade 20 is the same as the rotation direction of the impeller.

[0052] The blade height gradually decreases from the leading edge to the trailing edge of blade 20, with the blade height direction pointing from the tip surface 23 to the root surface 24. The larger blade height at the leading edge of blade 20 helps to enclose the fluid at the inlet, reducing fluid leakage losses. The smaller blade height at the trailing edge of blade 20 helps to reduce collision losses between blade 20 and the fluid at the outlet, improving the aerodynamic performance of the impeller.

[0053] Since the blade height gradually decreases from the front section to the tail section of the blade 20, the work capacity of the blade 20 decreases. Setting a convex surface at the tail section of the blade 20 can reduce drag loss. Therefore, through simulation experiments, it has been verified that when the tail section of the blade 20 accounts for 5% to 30% of the total length of the blade 20, the tail section of the blade 20 has a better effect on reducing drag loss, thus making the overall performance of the impeller better.

[0054] Grooves 30 are formed on the surface of the impeller. The orientation of the grooves 30 is consistent with the development direction of the flow channel. Since the blades 20 extend along a helical line, the flow channel also extends substantially along a helical line. The development direction of the flow channel is along its extension direction, from the end of the flow channel near the inlet to the end of the flow channel near the outlet. During the rotation of the impeller, vortices v are generated in the turbulence. The contact between the vortices v and the impeller surface causes energy loss, such as... Figure 4 As shown. By creating grooves 30 on the surface of the impeller, with the grooves 30 oriented in the same direction as the flow channel, the fluid motion can be guided and the airflow direction smoothed, resulting in smoother gas flow and improved impeller performance. Furthermore, the grooves 30 can lift the vortex v onto the ridge of the grooves 30, such as... Figure 5As shown, reducing the surface contact area between the vortex v and the impeller reduces energy loss caused by this contact. After being lifted, the vortex v can move along the groove 30. The ridges of the groove 30 restrict the direction of vortex v's movement, effectively preventing energy loss caused by lateral diffusion and development of the vortex v, reducing fluid flow resistance, and improving impeller performance. Furthermore, creating the groove 30 on the impeller surface does not require changing the overall size of the impeller; it can be designed and manufactured on existing impeller structures, saving design costs. Additionally, by creating the groove 30 on the impeller surface, some impeller material is removed, reducing the impeller's weight and thus reducing the load on the motor, indirectly increasing the impeller's rotational speed.

[0055] The groove 30 is formed on the surface of the hub 10 and extends from the front section of the hub 10 to the rear section of the hub 10. Optionally, the groove 30 may only extend from the front section of the hub 10 to the middle section of the hub 10. After the fluid enters the flow channel, the fluid velocity is relatively slow. The rotation of the blade 20 does work on the fluid, and the static pressure and kinetic energy of the fluid are increased simultaneously. When the fluid flows to the flow channel near the trailing edge of the blade 20, the fluid velocity is faster, and the pressure and velocity increase effect of the groove 30 on the fluid is slightly reduced. Therefore, the groove 30 set on the front section of the hub 10 can start to play a role when the fluid velocity is relatively slow, and the drag reduction effect is better. The flow channel near the trailing edge of the blade 20 has a lower drag reduction requirement than the front section. Therefore, depending on actual needs, the groove 30 may not be set at the rear section of the hub 10.

[0056] It is understandable that, depending on actual needs, the groove 30 can also be formed on the surface of the blade 20. For example, the groove 30 can be formed on the pressure surface 25 and / or suction surface 26 of the blade 20. Since the blade 20 is relatively thin, forming the groove 30 on its surface can easily lead to a decrease in the strength of the blade 20, a smaller operating space, and greater machining difficulty. Therefore, compared to forming the groove 30 on the surface of the blade 20, forming the groove 30 on the surface of the hub 10 can avoid a decrease in the strength of the blade 20, and provides a larger operating space and is easier to machine.

[0057] The cross-section of the groove 30 is triangular, which can form a sharkskin-like structure, namely a triangular groove rib structure, which has superior drag reduction and adhesion reduction properties.

[0058] Please see Figure 6The dimensions of the groove 30 need to be strictly limited. When the size of the vortex is smaller than the width of the groove 30, it will fall into the groove 30 and interact with the groove wall and the surface of the hub 10. When the size of the vortex is larger than the width of the groove 30, the vortex is lifted, reducing the contact area with the impeller surface and thus reducing the interaction. Therefore, only when the width and spacing of the groove 30 are appropriate can the wall friction resistance be smaller than that of a smooth plane, thereby achieving a drag reduction effect on the impeller surface. The depth-to-width ratio of the groove 30 is related to both its depth and width. A smaller depth-to-width ratio results in a larger groove width, making it easier for vortices to fall into the groove 30 and interact with the groove wall. A larger depth-to-width ratio results in a smaller groove width, making it harder for vortices to fall into the groove 30, reducing the contact area with the impeller surface and thus reducing the interaction. Therefore, only when the depth-to-width ratio of the groove 30 is appropriate and the wall friction resistance is smaller than that of the hub surface can a drag reduction effect be achieved.

[0059] Experimental tests showed that the effect of groove 30 in lifting the vortex structure is more significant when the parameters of groove 30 are as follows:

[0060] The optimal value is when the number of grooves 30 between two adjacent blades is 5 ≤ ​​n ≤ 12, and the number of grooves 30 between two adjacent blades is 6.

[0061] The central angle A of the bottom of two adjacent grooves 30 should be ≤ 4° and ≤ 10°, with 8.6° being optimal. It should be noted that the central angle A of the bottom of two adjacent grooves 30 is the angle formed by the lines connecting the bottom of the grooves near the impeller outlet and the bottom of the grooves near the impeller inlet. The larger the distance between two adjacent grooves 30, the larger the central angle A; conversely, the smaller the distance between two adjacent grooves 30, the smaller the central angle A.

[0062] The width L of the groove 30 is ≤0.14mm and ≤0.08mm.

[0063] The depth H of trench 30 is (1~1.5)L.

[0064] In some embodiments, the number of blades 20 is N=7, the number of grooves 30 between two adjacent blades 20 is n=6, the central angle A of the bottom of two adjacent grooves 30 is 8.6°, the width of the groove 30 is L=0.14mm, and the depth of the groove 30 is H=1.07L=0.15mm.

[0065] The width L of a single groove 30 accounts for 2% to 3% of the total circumference of the single flow channel outlet.

[0066] The total width of the groove 30 within a single flow channel accounts for 15-30% of the total circumference of the outlet of that single flow channel.

[0067] It should be noted that the total circumference S of a single flow channel outlet is the circumference of the hub's rear edge within a single flow channel, such as... Figure 3 As shown.

[0068] Example 2

[0069] On the one hand, since the hub 10 is roughly conical or frustum-shaped, the diameter of the front section of the hub 10 is relatively small. On the other hand, the groove 30 needs to maintain a certain width to avoid the inability to form a triangular groove structure. Therefore, the surface of the front section of the hub 10 can only accommodate a small number of grooves 30, resulting in a small number of grooves 30 on the entire hub 10. Based on this, according to the impellers provided in the aforementioned embodiments, Embodiment 2 of the present invention provides an impeller that is basically the same as the impeller provided in Embodiment 1, with the main difference being the structure of the grooves 30, as detailed below:

[0070] Please see Figure 7 and Figure 8 The groove 30 is divided into a long groove 32 and a short groove 34. The long groove 32 and the short groove 34 are arranged alternately. The long groove 32 extends from the front section of the hub 10 to the rear section of the hub 10, that is, the long groove 32 extends from the front section of the flow channel to the rear section of the flow channel. The short groove 34 extends from the middle section of the hub 10 to the rear section of the hub 10, that is, the short groove 34 extends from the middle section of the flow channel to the rear section of the flow channel. Since the hub 10 is roughly conical or frustum-shaped, and the diameter of the rear section of the hub 10 is larger, the flow channel gradually widens along the development direction of the flow channel. The spacing of the grooves 30 near the impeller outlet also gradually increases, resulting in a smaller spacing of the grooves 30 at the front section of the hub 10. The grooves 30 at the front section of the hub 10 have a better effect on lifting the vortex, and the vortex is less likely to fall into the grooves 30 at the front section of the hub 10. The drag reduction performance at the front section of the hub 10 is better. The grooves 30 at the middle section and the rear section of the hub 10 have a larger spacing, and the grooves 30 at the middle section and the rear section of the hub 10 have a poorer effect on lifting the vortex. The vortex is more likely to fall into the grooves 30 at the middle section and the rear section of the hub 10. The drag reduction performance at the middle section and the rear section of the hub 10 is poor. By setting the groove 30 as a long groove 32 and a short groove 34, the short groove 34 can make full use of the surface space of the rear section of the hub 10, while the number of long grooves 32 is basically equal to the number of grooves 30 before the improvement. Therefore, the groove spacing of the front section of the hub 10 remains basically unchanged, and the drag reduction performance of the front section of the hub 10 is basically unaffected. The groove spacing of the middle and rear sections of the hub 10 is reduced, and the grooves 30 in the middle and rear sections of the hub 10 improve the vortex lifting effect. The vortex is less likely to fall into the grooves 30 in the middle and rear sections of the hub 10, and the drag reduction performance of the middle and rear sections of the hub 10 is improved.

[0071] It is understandable that, depending on actual needs, long grooves 32 and short grooves 34 can also be formed on the surface of blade 20, for example, on the pressure surface 25 and / or suction surface 26 of blade 20. Since the blade height gradually decreases from the leading edge to the trailing edge of blade 20, the long grooves 32 extend from the trailing edge to the leading edge of blade 20, and the short grooves 34 extend from the middle section to the leading edge of blade 20. Compared to forming only long grooves 32 on the surface of blade 20, adding short grooves 34 to the surface of blade 20 keeps the groove spacing 30 at the trailing edge of blade 20 essentially unchanged, and the drag reduction performance at the trailing edge of blade 20 is basically unaffected. The groove spacing 30 at the middle and leading edges of blade 20 decreases, improving the vortex lifting effect and making it less likely for vortices to fall into the grooves 30 at the middle and leading edges of blade 20, thus improving the drag reduction performance at the middle and leading edges of blade 20.

[0072] The ratio of the length of the short groove 34 to the length of the long groove 32 is 0.3 to 0.5, and the overall aerodynamic performance of the impeller is optimal when the ratio of the length of the short groove 34 to the length of the long groove 32 is 0.33.

[0073] The alternating arrangement of long grooves 32 and short grooves 34 can be such that one or two short grooves 34 are provided between every two adjacent long grooves 32, or one or two long grooves 32 are provided between every two adjacent short grooves 34. In this embodiment, one short groove 34 is provided between every two adjacent long grooves 32.

[0074] The number of grooves between two adjacent blades is n≤20.

[0075] The number of long grooves (32) can be equal to the number of short grooves (34), or the number of long grooves (32) can differ from the number of short grooves (34) by 1.

[0076] The total width of the groove 30 in a single flow channel accounts for 20% to 50% of the total circumference of the outlet of the single flow channel. The aerodynamic performance of the impeller reaches its optimal level when the total width of the groove 30 in a single flow channel accounts for 29.3% of the total circumference of the outlet of the single flow channel.

[0077] It can be understood that in Example 1, 5 ≤ the number of grooves 30 between two adjacent blades 20 n ≤ 12, and in Example 2, 10 ≤ the number of grooves 30 between two adjacent blades 20 n ≤ 20. In summary, as long as 5 ≤ ​​the number of grooves 30 between two adjacent blades 20 n ≤ 20, it is acceptable.

[0078] It is understood that in Example 1, the total width of the grooves 30 within a single flow channel accounts for 15% to 30% of the total circumference of the outlet of the single flow channel, and in Example 2, the total width of the grooves 30 within a single flow channel accounts for 20% to 50% of the total circumference of the outlet of the single flow channel. In summary, it is sufficient as long as the total width of the grooves 30 within a single flow channel accounts for 15% to 50% of the total circumference of the outlet of the single flow channel.

[0079] It is worth noting that the impeller size or the number of blades 20 can be adjusted accordingly based on actual needs. With the same impeller size, increasing the number of blades 20 reduces the volume of a single flow channel, requiring a reduction in the number of grooves 30 to prevent excessive grooves 30 from forming the triangular groove rib structure. Conversely, decreasing the number of blades 20 increases the volume of a single flow channel, necessitating an increase in the number of grooves 30 to prevent excessive contact between the fluid vortex and the surface of the hub 10, which could lead to energy loss. Experiments have shown that as long as at least one of the following conditions is met, the impeller's aerodynamic performance and drag reduction effect can be maintained at an excellent level, as follows:

[0080] 5≤The number of grooves 30 between two adjacent blades n≤20;

[0081] The total width of the groove 30 within a single flow channel accounts for 15% to 50% of the total circumference of the outlet of that single flow channel.

[0082] The performance improvement of the impeller after adding grooves by 30 is mainly reflected in the fan vacuum degree and suction power index. Under the same conditions, the corrected vacuum degree and suction power are significantly improved, as shown in Table 1 and Table 2.

[0083] Table 1. Performance of the fan after adding 30 grooves to the impeller

[0084]

[0085] Table 2. Performance of the fan before adding grooves to the impeller (30mm).

[0086]

[0087] Note: The “aperture” in Tables 1 and 2 refers to the aperture of the testing device. Generally, when testing wind turbines, the test bench needs to test the performance under different apertures.

[0088] When the test results are taken as the standard with the test device having an aperture of 14 mm, it is considered that the impeller performance is excellent if the fan performance efficiency is higher than 45%. This application obtained the fan performance by keeping the impeller speed constant and changing the number of grooves or the ratio of the total width of the grooves in a single flow channel to the total circumference of the single flow channel outlet, with the test device having an aperture of 14 mm. The results are shown in Tables 3 and 4, respectively.

[0089] Table 3. Fan performance at a fixed impeller speed and with a test aperture of 14 mm.

[0090] number of trenches Flow rate dm^3 / s Calibrated vacuum kPa efficiency% 0 14.49 15.92 42.05 5 14.4 16.55 45.21 13 14.49 16.76 46.78 20 14.55 16.3 45.9 25 13.97 15.76 42.31

[0091] Table 4 shows the fan performance under a fixed impeller speed and with a test device orifice diameter of 14 mm.

[0092]

[0093] Based on the above experimental results, the number of grooves between two adjacent blades is selected to be 5 to 20, and the ratio of the total width of the grooves in a single flow channel to the total circumference of the single flow channel outlet is 15 to 50%. Within this range, the overall performance of the impeller is excellent.

[0094] The impeller testing setup includes an equalizing chamber, a thick steel orifice plate, a pressure gauge, and a frequency converter control cabinet. The thick steel orifice plate can be a flow control valve with 10 different orifice diameters. During testing, the motor is started, driving the impeller to rotate, and the vacuum level, input voltage, and current within the equalizing chamber are measured. The flow rate is calculated from the calibrated orifice plate; the orifice diameter is continuously adjusted during the experiment to change the flow rate, achieving variable operating condition measurement, thereby obtaining flow rate, vacuum level, and efficiency data.

[0095] Example 3

[0096] Embodiment 3 of the present invention provides a fan, including a fan housing, a motor, and an impeller provided in Embodiments 1 and 2. The impeller is housed within the fan housing, and the output shaft of the motor is connected to the impeller to drive the impeller to rotate.

[0097] Example 4

[0098] Embodiment 4 of the present invention provides a vacuum cleaner, including the fan described in Embodiment 3. In this embodiment, the vacuum cleaner is not limited to canister, horizontal, upright, or handheld vacuum cleaners, and robots or other devices with vacuuming functions also fall under the category of vacuum cleaners in this application. Robots with vacuuming functions include robotic vacuum cleaners, robotic mopping robots, etc.

[0099] Compared with existing technologies, in the impeller, fan, and vacuum cleaner provided in this embodiment of the invention, by creating grooves 30 on the surface of the impeller, with the grooves 30 oriented in the same direction as the flow channel, the fluid movement can be guided and the airflow direction smoothed, resulting in smoother gas flow and improved impeller performance. Furthermore, the grooves 30 can lift vortices onto the ridges of the grooves 30, reducing the surface contact area between the vortex and the impeller, thus reducing energy loss caused by surface contact. After being lifted, the vortex can move along the grooves 30, reducing energy loss caused by lateral diffusion and development of the vortex, reducing fluid flow resistance, and improving impeller performance. Moreover, creating grooves 30 on the surface of the impeller does not require changing the overall size of the impeller; it can be designed and manufactured on existing impeller structures, saving design costs. Furthermore, by creating grooves 30 on the surface of the impeller, some material is removed, reducing the weight of the impeller and thus reducing the load on the motor, indirectly increasing the impeller speed.

[0100] In addition, by setting the pressure surface 25 at the front of the blade 20 to be concave, with the concave direction opposite to the rotation direction of the impeller, it is beneficial to conform to the fluid flow. Furthermore, the pressure surface 25 at the front of the blade 20 can form a wrap around the fluid at the air inlet, which can reduce the leakage loss of the fluid at the air inlet, expand the pressure surface 25 of the impeller at low flow rates, increase the contact area between the pressure surface 25 and the fluid, and improve the impeller performance.

[0101] In addition, the size of the impeller and the number of blades can be adjusted according to actual needs. As long as the number of grooves 30 between two adjacent blades 20 is 20 or less, or the total width of the grooves 30 in a single flow channel accounts for 15% to 50% of the total circumference of the outlet of a single flow channel, the aerodynamic performance and drag reduction effect of the impeller can be maintained at an excellent level.

[0102] In addition, compared to setting only one groove 30 on the surface of the impeller, since the surface of the impeller is usually irregular or non-uniform, the combination of long groove 32 and short groove 34 can better adapt to the shape of the impeller and ensure the drag reduction effect.

[0103] In addition, by extending the surface of the hub 10 near the trailing edge surface 22 of the blade 30, the connection between the blade tip surface 23 and the trailing edge surface 22 of the blade 30 is smoothly transitioned with rounded corners. This can better guide the fluid that does work through the blade 30 to be basically parallel to the axial direction of the hub 10, reduce the collision loss between the blade tip surface 23 and the trailing edge surface 22 and the fluid, and improve the performance of the impeller.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An impeller, characterized in that, It includes a hub and blades, and there are multiple blades distributed in the circumferential direction of the hub, with a flow channel formed between each pair of adjacent blades; A first groove is formed on the surface of the wheel hub. The first groove includes a long groove and a short groove, and the long groove and the short groove are alternately arranged. The long groove extends from the front section of the flow channel to the rear section of the flow channel, and the short groove extends from the middle section of the hub to the rear section of the hub. The width of the first trench is L, and the depth of the first trench is H, where H = (1~1.5)L; 5 ≤ the number of the first grooves between two adjacent blades n ≤ 20; or / and, The total width of the first groove within a single flow channel accounts for 15% to 50% of the total circumference of the outlet of the single flow channel.

2. The impeller according to claim 1, characterized in that, The radius of the wheel hub increases from the front to the rear. The long groove extends from the front to the rear of the wheel hub, and the short groove extends from the middle to the rear of the wheel hub.

3. The impeller according to claim 1, characterized in that, The second groove is formed on the surface of the blade.

4. The impeller according to claim 3, characterized in that, The blade includes a pressure surface and a suction surface, and the second groove is provided on the pressure surface and / or the suction surface. The pressure surface is the side of the blade facing the rotation direction of the impeller, and the suction surface is the side of the blade away from the rotation direction of the impeller.

5. The impeller according to claim 4, characterized in that, The second groove includes a long second groove and a short second groove. The blade height decreases from the front section to the rear section of the blade. The long second groove extends from the rear section of the blade to the front section of the blade, and the short second groove extends from the middle section of the blade to the front section of the blade.

6. The impeller according to claim 1, characterized in that, The number of long grooves is equal to the number of short grooves; or, the number of long grooves differs from the number of short grooves by 1.

7. The impeller according to claim 1, characterized in that, The ratio of the length of the short groove to the length of the long groove is 0.3 to 0.

5.

8. The impeller according to claim 1, characterized in that, The total width of the first groove within a single flow channel accounts for 20% to 50% of the total circumference of the outlet of the single flow channel.

9. The impeller according to claim 1, characterized in that, 10 ≤ the number of the first grooves between each pair of adjacent blades n ≤ 20.

10. The impeller according to claim 1, characterized in that, The surface of the middle section of the hub is concave inward toward the axis of the hub, and the surface of the rear section of the hub is convex outward away from the axis of the hub. The cross-section of the first groove is triangular.

11. The impeller according to claim 1, characterized in that, The angle between the extension direction of the surface at the rear periphery of the hub and the axial direction of the hub is 0° to 50°.

12. A fan, characterized in that, Includes the impeller as described in any one of claims 1 to 11.

13. A vacuum cleaner, characterized in that, Includes the wind turbine as described in claim 12.

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