An impeller and a voluteless fan having the same

Abstract

The application relates to the technical field of fans, in particular to an impeller and a volute-free fan with the same, the volute-free fan comprising, in sequence along the Z-axis direction, an air inlet mounting panel, the impeller, a motor and a fan mounting panel, the air inlet mounting panel being provided with an air inlet, the air inlet being connected with one end of the impeller in a matched mode to form a gradually expanding airflow channel, and each parameter of the impeller being optimized in design. The application is verified through a sand dust test, and under the same conditions, the dust accumulation amount is reduced by 86%, the influence of dust accumulation on the rotor unsteadiness of the fan is greatly reduced, and the equipment maintenance cycle and service life are significantly prolonged.

Description

Technical Field

[0001] This application relates to the field of fan technology, specifically to an impeller and a volute-less fan with the impeller for preventing dust accumulation in a three-dimensional flow. Background Technology

[0002] Centrifugal fans are core components of the ventilation and cooling systems of rail transit vehicles. Their long-term stable operation directly determines the comfort of the environment inside the carriage and has a significant impact on the operational safety of various core equipment in the vehicle. They are one of the fundamental components that ensure the reliable operation of rail transit vehicles.

[0003] In existing technologies, centrifugal fan impeller blades mostly adopt a single-plate or simple arc-shaped structure. Their flow channel design does not fully consider the three-dimensional flow field characteristics during actual operation of rail transit fans, leading to the formation of stable negative pressure vortex zones in the non-working surfaces of the blades (especially in the impeller front plate area). These negative pressure vortex zones create a strong dust particle capture effect, becoming the main area for dust adhesion. When the accumulated dust reaches a certain thickness, uneven shedding can easily occur, disrupting the impeller's dynamic balance and causing severe fan vibration. This not only leads to a significant increase in wind resistance and abnormal motor load but can also cause fan malfunctions and shutdowns in severe cases, directly affecting the normal operation of rail transit vehicles. To address the aforementioned dust accumulation problem, existing technologies mostly employ passive protection methods such as adding block-shaped protrusions or anti-dust plates to the blade surface. While these solutions can reduce dust adhesion in localized areas, they significantly disrupt the continuity of the internal flow field of the fan, leading to a substantial decrease in fan operating efficiency. Furthermore, their design is not fully adapted to the unique volute-less structure of rail transit fans, resulting in poor installation compatibility and unstable anti-dust accumulation effects, making it difficult to meet practical application requirements. Meanwhile, although three-dimensional flow impeller technology has been applied in the industrial fan field, proving its ability to improve fan operating efficiency through precise optimization of flow field distribution, to date, no technical solution has emerged that combines three-dimensional flow impeller technology with the volute-less structure of rail transit fans to control dust accumulation at its source. This fails to simultaneously meet the dual requirements of efficient fan operation and improved dust accumulation control.

[0004] Therefore, there is an urgent need for a fan structure that balances efficient operation with dust accumulation reduction. By optimizing the impeller design, dust accumulation can be controlled at the source of the flow field, thus meeting the stringent requirements of the rail transit sector for high equipment reliability and low maintenance costs. Utility Model Content

[0005] The purpose of this application is to provide an impeller and a volute-less fan with the impeller, so as to solve the problems of serious dust accumulation on impellers in the rail transit field, serious dust accumulation and low operating efficiency of volute-less fans due to poor impeller structure adaptability and unreasonable flow field design.

[0006] The embodiments of this application can be implemented through the following technical solutions: An impeller includes a front impeller disk, a rear impeller disk, and a plurality of three-dimensional flow blades connecting the front and rear impeller disks. Along the Z-axis, the space between the profiles of the front and rear impeller disks facing each other is equally divided into four small flow channels, forming five different flow channel lines a, b, c, d, and e, where a is the front disk profile line and e is the rear disk profile line. The intersection lines of these five lines with the same three-dimensional flow blade are... , , , , , , , , , The projection lines i on the cross section perpendicular to the Z-axis are denoted as follows: , , , , ; The specific design parameter ranges are as follows: Wherein, the curved surface connecting the three-dimensional flow blade to the impeller front disk is the front blade root, and the outlet edge diameter of the front blade root is the same as the blade outlet edge diameter. The straight-line distance from the endpoint of projection line i at the outlet edge to the center of the fan's rotating shaft is the outlet projection diameter. The distance from the inlet endpoint of projection line i to the projection axis is the inlet projection diameter. The angle between the tangent at the endpoint of projection line i and the tangent of the arc from the endpoint to the projection axis is the projection entrance angle. The angle between the tangent to projection line i at its endpoint at the exit edge and the tangent to the arc from its endpoint to the projection axis is the projection exit angle. .

[0007] Furthermore, along the airflow direction from the inlet to the outlet, the angle between the circumferential angle difference formed by the i-th projection line and its adjacent projection line at the corresponding two radii on the outlet side is the misalignment angle. , , , , misalignment angle The design parameter range is 0-6, 0-5, 0-4, 0-3.

[0008] Furthermore, the impeller front disc is composed of a tangent front disc arc segment and a front disc straight segment, wherein the forming angle of the front disc straight segment is... The range is 0°-25°, the ratio of the inlet projection diameter D04 of the impeller front plate to the outlet outer diameter D05 of the impeller front plate is 0.65-0.8, and along the Z-axis direction, the ratio of the height H05 of the impeller front plate to the height H07 of the impeller is 0.3-0.6.

[0009] Furthermore, the impeller rear disk is composed of a first straight segment, a first arc segment, a second straight segment, and a second arc segment connected in sequence, wherein the forming angle of the second straight segment is... The range is 15°-35°; the ratio of the center diameter D06 of the rear disc center hole to the outlet outer diameter D05 of the front disc of the impeller is 0.3-0.5; the ratio of the outer edge diameter D07 of the rear disc to the outlet outer diameter D05 of the front disc of the impeller is 0.8-1; the ratio of the height H06 of the rear disc to the height H07 of the impeller is 0.4-0.75; the ratio of the height H07 of the impeller to the outlet outer diameter D05 of the front disc of the impeller is 0.21-0.35.

[0010] Furthermore, the curved surface connecting the three-dimensional flow blade to the impeller front disk is the front blade root, and the outlet edge diameter of the front blade root is... The ratio of the outer diameter D05 of the impeller front disc to the outlet diameter D05 ranges from 0.48 to 0.493.

[0011] Furthermore, the number of the three-dimensional flow blades is 7-15.

[0012] Furthermore, the outlet edge of the three-dimensional flow blade is provided with several serrations to... This indicates the length of the outlet edge of the three-dimensional flow blade. This indicates the spacing between two adjacent saw teeth. Specifically, there are no saw teeth in the one-third area closest to the outlet edge of the impeller front disc, and the saw teeth are only arranged in the remaining two-thirds area. The spacing between two adjacent saw teeth... The length of the outlet edge of the three-dimensional flow blade The ratio ranges from 0.11 to 0.15.

[0013] A volute-less fan includes an impeller as described above, and also includes an air inlet mounting panel, a motor, and a fan mounting panel connected along the vertical rotation axis Z-axis. The air inlet mounting panel is provided with an air inlet, which is connected to one end of the impeller to form a gradually expanding airflow channel; The air inlet includes an air inlet neck section, which is composed of a circular arc segment and a straight line segment rotated together, with the straight line segment being tangent to the circular arc segment; wherein, the ratio of the air inlet diameter D01 to the air outlet diameter D02 of the air inlet ranges from 1.02 to 1.6.

[0014] Furthermore, the minimum diameter of the air inlet is the throat diameter D03, the ratio of the throat diameter D03 of the air inlet to the air outlet diameter D02 of the air inlet is in the range of 0.92-0.95, and the ratio of the throat height H02 to the air inlet height H01 is in the range of 0.35-0.5.

[0015] Furthermore, the overlap depth between the impeller front disc and the air inlet is 5-10mm, and the overlap gap is 1-4mm.

[0016] The impeller and volute-less fan provided by the embodiments of this application have at least the following beneficial effects: This application constructs a collaborative dust prevention system through multi-dimensional structural optimization, significantly improving the impeller's ability to prevent dust accumulation: through precise design / , / , , Parameters such as these ensure a smooth, diffused flow field in the flow channel, with gradual and abrupt velocity changes, reducing the formation of negative pressure vortices at the source. A serrated structure with specific dimensional ratios is used at the blade outlet edge to break up the stable vortex at the tail end into easily dissipated micro-vortices, disrupting the flow field conditions for continuous dust adhesion. Simultaneously, the impact force of the airflow adhering to the wall continuously scours the blade surface. Optimizing the overlap depth and gap between the impeller and the inlet, along with a reasonable blade spacing design, avoids low-velocity or dead zones within the flow channel, enhancing the airflow's dust-carrying capacity and ensuring dust is quickly discharged with the mainstream. Multiple insulation structures are superimposed to block electrochemical corrosion caused by stray currents, reducing dust adsorption on corroded surfaces. Finally, sand and dust tests verified that under the same conditions, dust accumulation was reduced by 86%, significantly reducing the impact of dust accumulation on the fan rotor's instability and significantly extending the equipment's maintenance cycle and service life. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a volute-less fan according to this application; Figure 2 This is a side sectional view of a volute-less fan according to this application; Figure 3 This application presents a schematic diagram of the air inlet structure of a volute-less fan; Figure 4 This is a schematic diagram of the impeller structure in this application; Figure 5a To modify the front impeller flow area curve schematic diagram; Figure 5b This is a schematic diagram of the flow area curve of the fan impeller in this application; Figure 6a To change the vector diagram of the velocity in the front flow field on the axial section; Figure 6b This is a vector diagram of the velocity in the flow field on the axial section in this application; Figure 7 A schematic diagram of the flow channel on the shaft section of the wind turbine impeller in this application; Figure 8 This is a schematic diagram of the intersection line between the small flow channel line and the blade of the wind turbine impeller shaft section in this application; Figure 9 This is a schematic diagram of the cross-section projection of the intersection line of the small flow channel line and the blade of the wind turbine impeller in this application. Figure 10 This is a schematic diagram of the serrated shape of the outlet edge of the wind turbine impeller blade in this application; Figure 11a To change the vector diagram of the velocity in the front flow field on the cross section at the maximum diameter of the front disk; Figure 11b This is a vector diagram of the wind turbine speed in this application on the cross-section at the maximum diameter of the front disc; Figure 12 This is a schematic diagram of the fan inlet structure of this application; Figure 13a This is a vector diagram of the fan speed in the impeller region from the front disc visible view in Embodiment 1 of this application; Figure 13b This is a vector diagram of the fan speed in the impeller region from the rear disc visible view in Embodiment 1 of this application; Figure 14a This is a vector diagram of the fan speed in the impeller region from the front disc visible view in Embodiment 2 of this application; Figure 14b This is a vector diagram of the fan speed in the impeller region from the rear disc visible view in Embodiment 2 of this application; Figure 15a This is a vector diagram of the fan speed in the impeller region from the visible front disc perspective, as shown in this application. Figure 15b This is a vector diagram of the fan speed in the cross section near the rear disc, which is a comparative example of this application.

[0018] Numbers in the diagram 1-Inlet mounting panel; 2-Impeller front plate; 3-Impeller rear plate; 4-Three-dimensional flow blades; 5-Shaft sleeve; 6-Motor; 7-Motor connecting bracket; 8-Fan mounting panel; 9-Panel reinforcement frame; 10-Inlet; 11-Inlet connecting bracket; 12-Inlet sealing gasket; 13-Inlet insulation plate; 14-Panel sealing gasket; 15-Panel insulation gasket; 16-Connector; 101 - Air inlet flange; 102 - Air inlet neck section; 103 - Large diameter through hole; 104 - Small diameter through hole; 105 - Circular arc segment; 106 - Straight line segment; 201 - Front disc arc segment; 202 - Front disc straight line segment; 301 - Rear disc first straight line segment; 302 - Rear disc second straight line segment; 303 - Rear disc second arc segment; 304 - Rear disc first arc segment. Detailed Implementation

[0019] The present application will now be further described based on preferred embodiments and with reference to the accompanying drawings.

[0020] Furthermore, for ease of understanding, various components on the drawings have been enlarged or reduced, but this is not intended to limit the scope of protection of this application.

[0021] Singular forms of words also include plural meanings, and vice versa.

[0022] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, they are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation on this application. In addition, in the description of this application, in order to distinguish different units, the terms "first," "second," etc. are used in this specification, but these are not limited by the manufacturing order, nor should they be construed as indicating or implying relative importance. Their names may differ in the detailed description and claims of this application.

[0023] The vocabulary used in this specification is for illustrative purposes and is not intended to limit the scope of this application. It should also be noted that, unless otherwise expressly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection via an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of these terms in this application.

[0024] For ease of description, the direction of the fan's rotation axis is marked as the Z-axis. The airflow flows axially from the negative Z-axis side (air inlet end) to the positive Z-axis side (air inlet outlet end, near the impeller).

[0025] Specifically, such as Figure 1 , Figure 2As shown, a volute-less fan includes an inlet mounting panel 1, an impeller, a motor 6, and a fan mounting panel 8 connected sequentially along the Z-axis. The inlet mounting panel 1 is provided with an inlet 10, which is connected to one end of the impeller to form a gradually expanding airflow channel. This allows the airflow to be stably guided by a straight section first, and then smoothly transitioned through a circular arc section. The design with the straight section in front can stabilize the airflow from the source and avoid airflow turbulence at the inlet end. The smooth transition with the circular arc section behind can reduce the impact of airflow turning. There are no obvious airflow abrupt changes throughout the process, which reduces the formation of negative pressure vortex zones from the root of the flow field and significantly reduces the risk of dust adhesion on the non-working surfaces of the blades and the front plate of the impeller.

[0026] The gradually expanding airflow channel is achieved through the following structural design: In some preferred embodiments, such as Figures 1 to 3 As shown, the air inlet 10 includes an air inlet neck section 102, which is formed by rotating an arc segment 105 and a straight segment 106, with the straight segment 106 tangent to the arc segment 105. The ratio of the air inlet diameter D01 to the air outlet diameter D02 of the air inlet 10 ranges from 1.02 to 1.6. The minimum diameter of the air inlet 10 is the throat diameter D03, and the ratio of the throat diameter D03 to the air outlet diameter D02 ranges from 0.92 to 0.95. The ratio of the throat height H02 to the air inlet height H01 ranges from 0.35 to 0.5. When the ratio is too small, the turning radius of the airflow is small, the flow loss is large, the guiding effect of the air inlet on the airflow is weakened, and the high-efficiency zone of the performance curve becomes narrower. When the ratio is too large, the airflow enters the throat of the air inlet from the outer area, the flow velocity rises rapidly in a short distance, the flow loss increases, and the airflow is prone to separation before entering the impeller.

[0027] In some preferred embodiments, the air inlet 10 of the fan has a structure that expands outward at both ends and is concave in the middle. The air inlet diameter D01 refers to the port diameter at the airflow inlet end, the air outlet diameter D02 refers to the port diameter at the airflow outlet end, and the throat diameter D03 refers to the minimum cross-sectional diameter of the concave area in the middle.

[0028] In some preferred embodiments, such as Figure 4 As shown, the impeller includes a front impeller plate 2, a rear impeller plate 3, and several three-dimensional flow blades 4. The front impeller plate 2 is connected to the air inlet 10. The rear impeller plate 3 is coaxially connected to the drive end of the motor 6. The other end of the motor 6 is fixedly connected to the fan mounting panel 8. Several three-dimensional flow blades 4 are connected between the front impeller plate 2 and the rear impeller plate 3 along the circumferential direction of the Z-axis.

[0029] In some preferred embodiments, the impeller front disc 2 is composed of a front disc arc segment 201 and a front disc straight segment 202, wherein the front disc arc segment 201 and the front disc straight segment 202 are tangent, the radius of the front disc arc segment 201 is in the range of 40mm-80mm, and the forming angle of the front disc straight segment 202 is... The range is 0°-25°. The ratio of the inlet projection diameter D04 of the impeller front plate 2 to the outlet outer diameter D05 of the impeller front plate 2 is 0.65-0.8. Along the Z-axis direction, the ratio of the height H05 of the impeller front plate 2 to the height H07 of the impeller is 0.3-0.6.

[0030] In some preferred embodiments, along the Z-axis, the impeller rear disk 3 is composed of a first straight segment 301, a first arc segment 304, a second straight segment 302, and a second arc segment 303 connected in sequence. Both arc segments of the impeller rear disk 3 are tangent to their adjacent straight segments. The radius of the second arc segment 303 ranges from 150mm to 450mm; the radius of the first arc segment 304 ranges from 10mm to 50mm; and the forming angle of the second straight segment 302 is... The range is 15°-35°; the ratio of the center diameter D06 of the rear disc center hole end of the impeller rear disc 3 to the outlet outer diameter D05 of the outer edge of the front disc of the impeller front disc 2 ranges from 0.3 to 0.5; the ratio of the outer edge diameter D07 of the rear disc of the impeller rear disc 3 to the outlet outer diameter D05 of the outer edge of the front disc of the impeller front disc 2 ranges from 0.8 to 1; the ratio of the height H06 of the impeller rear disc 3 to the height H07 of the impeller ranges from 0.4 to 0.75; the ratio of the height H07 of the impeller to the outlet outer diameter D05 of the outer edge of the front disc of the impeller front disc 2 ranges from 0.21 to 0.35.

[0031] With the above settings, the gradient of curvature change in the airflow area curve is significantly improved, such as... Figure 6a , Figure 6b Comparison diagram: Figure 5a To modify the schematic diagram of the front impeller flow area curve, the entire curve has protrusions and chaotic curvature changes, indicating that the airflow velocity distribution in the flow channel is uneven and changes drastically. The area where the four points at the end of the curve of the three-dimensional flow blade 4 are located is horizontal and has a downward trend. This not only causes the flow channel itself to have no pressure boosting capacity, but also prevents the pressure boosting function of the three-dimensional flow blade 4 from being utilized. At the same time, it causes an abnormal increase in airflow velocity acceleration, resulting in unnecessary kinetic energy loss, and is prone to inducing turbulence, exacerbating energy loss and the risk of dust adhesion.

[0032] Figure 5bThis is a schematic diagram of the flow area curve of the impeller of the wind turbine of the present invention. Due to the influence of the bushing and the change in the direction of airflow, the spatial shape changes in the first half of the curve, which slightly decreases to provide pre-guidance for the smooth entry of the medium into the impeller. The three-dimensional flow blade 4 also corresponds to the area where the four points at the end of the curve are located. This section of the curve is a parabola opening upward, which can realize the efficient conversion of some air kinetic energy into pressure energy. The shape of the entire curve is natural and smooth, following a quadratic function. The curvature changes gradually without abrupt changes or singularities. Simultaneously, the total length of the flow channel is shortened, reducing both disk friction losses and the total area where dust can adhere, thus laying a solid foundation for the effective work of the three-dimensional flow blades 4 and the smooth passage of the medium in this region.

[0033] Figure 6a This is a vector diagram of the velocity in the flow field on the axial section before the impeller structure was modified. Figure 6b This is a vector diagram of the velocity in the flow field of the fan of the present invention on the axial section. As can be seen from the figure, the low-speed vortex region on the back of the three-dimensional flow blade 4 has been significantly eliminated after the modification, the flow velocity state of the gas after being discharged from the impeller has been significantly improved, and the flow field uniformity has been greatly improved.

[0034] This application optimizes the impeller structure design, enabling the flow channel formed by the impeller front disk 2 and the impeller rear disk 3 to have excellent diffusion capacity, significantly improving the impeller's working efficiency. At the same time, it achieves smooth changes in airflow velocity without abrupt changes, reducing vortex formation at the source. The airflow velocity acceleration at the impeller outlet is greatly reduced, effectively reducing operating noise. The ability of the airflow to carry particles in the blade area is significantly enhanced, optimizing the flow field characteristics from multiple dimensions.

[0035] Specifically, this invention redesigns the three-dimensional flow blades to precisely match the front and rear disc structures and equipment operating conditions, and to highly adapt to the characteristics of the flow space. At the same time, it optimizes the blade profile to promote stable wall-hugging flow on the blade surface, reducing dust adhesion through the impact force of the airflow. In addition, by rationally designing the impeller blade spacing and inlet and outlet angles, it effectively reduces airflow separation, reduces the backflow area, ensures that particles are quickly discharged with the mainstream airflow, avoids low-velocity zones or dead zones in the flow channel, and allows the airflow to continuously scour the blade surface, fundamentally inhibiting dust deposition.

[0036] Furthermore, along the direction perpendicular to the Z-axis of rotation, the space between the two profiles of the impeller front disc 2 and the impeller rear disc 3 facing each other is equally divided into four small flow channels. Preferably, the space between the four small flow channels has equal volume, forming five different small flow channel lines a, b, c, d, and e, where a is the front disc profile line, e is the rear disc profile line, and the outlet projection diameter is as follows: Figure 7 , Figure 8 As shown, the intersection of these 5 lines with the same three-dimensional flow blade 4 is... , , , , ,like Figure 8 As shown, , , , , The projection lines i on the cross section perpendicular to the Z-axis are denoted as follows: , , , , ,like Figure 9 As shown, the straight-line distance from the endpoint of projection line i at the outlet edge to the center of the fan's rotation axis is the outlet projection diameter. The distance from the inlet endpoint of projection line i to the axis is the inlet projection diameter. Projection entrance angle The projection exit angle is the angle between the tangent at the endpoint of projection line i at its inlet and the tangent of the arc from the endpoint to the projection axis. The angle between the tangent to projection line i at its endpoint at the exit edge and the tangent to the arc from its endpoint to the projection axis is called the misalignment angle. Let be the circumferential angle difference between the projection line of line i and the projection line located adjacent to its outlet end at the two radii of the outlet edge. Let i be the projection line of a single three-dimensional blade on the cross-section perpendicular to the Z-axis, and let i be the position number of the projection line. The angle occupied along the impeller circumference is represented by the projection line number. , , , , The specific design parameter range is as follows: Wherein, the curved surface connecting the three-dimensional flow blade 4 to the impeller rear disk 3 is the rear blade root, the curved surface connecting the three-dimensional flow blade 4 to the impeller front disk 2 is the front blade root, the inlet is the edge where the airflow enters, and the outlet is the edge where the airflow exits.

[0037] , It is the core key parameter for improving blade flow and inhibiting dust accumulation, and it is mainly reflected in the following aspects.

[0038] To prevent "inlet vortexes" at the source and reduce initial dust accumulation, the main issue is that the blade inlet is the "connection point" where airflow enters the flow channel from the air inlet. If... With airflow at the inlet radius The incoming flow direction at the location does not match (e.g.) If the airflow is too large, it will "collide head-on" with the blade inlet; or If the airflow is too small (it "spins around" the blade inlet), it will cause the airflow to prematurely detach from the blade surface at the front disc, forming a "vortex zone." This vortex zone is a negative pressure area that actively adsorbs dust particles in the airflow, forming initial dust accumulation; while a reasonable... (Matching the angle with the incoming flow direction) allows the airflow to enter smoothly along the blade inlet profile, avoiding impact and separation, eliminating the inlet vortex area from the source, cutting off the formation path of initial dust accumulation, and at the same time, allowing the airflow to enter the flow channel at a stable flow rate, ensuring that dust particles flow smoothly with the airflow and do not settle prematurely.

[0039] Optimizing "outlet diffuser and flow rate" to suppress outlet ash accumulation and backflow is mainly reflected in: It is the core control parameter of the diffuser capability—when When designed with a reasonable acute angle (or within a specific angle range), the blade exit profile can guide the airflow to efficiently convert the "kinetic energy" gained from rotation into "pressure energy" as it leaves the blade, preventing the formation of a negative pressure vortex zone at the exit due to excessively low pressure. Negative pressure vortices are a major source of dust adhesion, especially in volute-less fans where the absence of a volute at the outlet makes them more prone to stabilization. Optimization... This can enhance the diffusion effect, eliminate or weaken the negative pressure vortex zone at the outlet, and reduce dust adhesion. If If the angle is too small (acute), the airflow velocity at the exit will decrease, resulting in insufficient energy conversion capacity; if If the airflow is too large, a separation zone will form, causing a sharp drop in airflow velocity. Dust particles, lacking sufficient kinetic energy, will settle directly in the blade exit area. A reasonable... This allows the airflow to leave the blades at a gentle speed, which avoids dust impact and deposition while ensuring the airflow's ability to carry dust, thus smoothly expelling the dust from the fan and reducing dust accumulation at the blade outlet.

[0040] In addition, in the process of achieving optimal flow conditions and preventing dust accumulation on the blades, the radial proportional parameter... / (Ratio of blade inlet radius to characteristic reference radius) / (Ratio of blade exit radius to characteristic reference radius) and angular parameters (Projection entrance angle) The (projected exit angle) is an interconnected parameter system: the radial proportional parameter provides the "spatial boundary" for the angle parameter, while the angle parameter provides "direction and path guidance" for the airflow within the radial space. Both need to be optimized synchronously and dynamically adapted. Determining the angle parameter in isolation from the radial proportional parameter will cause the angle design to lose spatial support, failing to achieve its function of controlling flow and preventing dust accumulation; optimizing only the radial proportional parameter while ignoring the angle parameter will also lead to turbulent flow due to uncontrolled airflow direction. Only by coordinating and adjusting both as a whole can a suitable flow channel space and guidance mechanism be constructed to achieve optimal flow conditions and completely suppress dust accumulation.

[0041] Specifically, Its core function is to ensure that the airflow enters smoothly along the blade inlet, and its appropriate value needs to be determined based on... / Based on: If / A ratio that is too small (the inlet radius is too narrow relative to the reference radius) means that the radial space for airflow at the inlet is limited. If designed at a large angle, it can easily cause airflow to impact and separate within a narrow space, forming a vortex region; if / The ratio is too large (the import radius is too wide). If the angle is small, it may cause the airflow to disperse within the wide inlet space, reducing flow velocity stability. Only by combining... / Determined inlet radial dimensions, matching Only by adjusting the angle can the airflow enter in the optimal direction within the suitable radial space, avoiding inlet vortex and dust settling.

[0042] for (Projection exit angle) and / Both factors together determine the "diffraction efficiency and velocity distribution" at the blade outlet: The direction of the airflow outlet and the efficiency of kinetic energy conversion are controlled by angle design. / Then define the radial range of the outlet—if / An unreasonable ratio (e.g., the export radius is too large relative to the reference radius), even Even with an optimal angle, excessively wide radial space at the outlet can lead to excessive airflow diffusion, weakening the diffusion effect and creating a negative pressure vortex region; if / Too small A larger angle is required to meet design parameters, but a large angle can easily cause airflow separation, leading to airflow congestion and exacerbating sudden changes in flow velocity. Only by... / Optimize to a suitable radial ratio, and then combine Only by adjusting the angle can the airflow achieve efficient diffusion at the outlet while maintaining a gentle flow velocity, thus avoiding dust adhesion and deposition.

[0043] In conclusion, / , / and , It is an interconnected parameter system: the radial proportional parameter provides the "spatial boundary" for the angular parameter, and the angular parameter provides the "direction and path guidance" for the airflow in the radial space. Only by coordinating the two as a whole can a suitable flow channel space and guidance mechanism be constructed to achieve the optimal flow conditions and completely suppress dust accumulation.

[0044] In addition, corner wrapping It also has advantages in extending the "airflow guidance path" and optimizing the stability of the entire flow channel, as well as the blade wrap angle. The larger the blade, the longer the circular path of the airflow within the flow channel between the blades, and the more sufficient the "guiding and work time" of the blades for the airflow—shorter wrap angle ( Too small a blade will cause the airflow to "pass through quickly" within the flow channel, preventing the blades from fully managing the airflow and easily leading to the formation of localized vortices due to insufficient airflow movement; a reasonable size... This allows the airflow to gradually adapt to the changes in the blade profile within the flow channel, avoiding airflow turbulence caused by excessively short movement paths, reducing vortex areas within the flow channel (especially vortices in the middle region of the blade), and lowering the probability of dust adhesion within the flow channel. The size directly affects the circumferential distribution density of the blades (for the same impeller diameter, The larger the size, the fewer the number of leaves; The smaller the size, the more leaves there are. If the blades are too large, have too many blades, or too narrow a blade spacing, airflow can easily become congested within the flow channel, causing sudden increases and decreases in flow velocity, forming localized eddies and dust deposition, thus failing to meet design parameters; if If the blade spacing is too small, the number of blades will be too few, the blade spacing will be too wide, the airflow filling will be insufficient, and the airflow will easily disperse and form small, scattered vortices. A reasonable ∅ can balance the blade spacing and the flow channel cross-section, ensuring that the airflow flows evenly and stably within the flow channel, without obvious congestion or dispersion, and reducing dust deposition.

[0045] Based on this, This optimizes the uniformity of the outlet flow field and indirectly helps prevent dust accumulation. Its core function is to control the circumferential position difference of the outlet projection of adjacent flow channels, indirectly controlling the tilt angle of the blades in each small flow channel, and controlling the normal direction of the blade surface. If Both are 0, the blade exit edges are located on the same axial section, the blade exit portion is not twisted, similar to a two-dimensional blade, suitable for situations where the exit portions of the front and rear disks are perpendicular to the axis and the two disks are parallel, but has poor adaptability to non-parallel front and rear disks; if Excessive tilt angle increases the blade's inclination relative to the front and rear disks, worsens its verticality, and forms a diamond-shaped flow channel, increasing wetted perimeter, frictional losses, and weakening flow capacity. An inappropriate misalignment angle leads to uneven circumferential airflow distribution at the outlets of each flow channel—in some areas, the outlet spacing is too narrow, causing airflow congestion and a sudden increase in velocity; in other areas, the spacing is too wide, causing airflow dispersion and a sudden decrease in velocity, forming a "circumferentially biased vortex zone." This vortex zone adsorbs dust particles, especially in the junction area between the impeller outlet and the non-volute structure, where circumferential bias exacerbates airflow turbulence, leading to dust deposition at the junction. When properly designed, a square or near-circular flow channel is formed, reducing circumferential friction loss, increasing flow capacity, and ensuring uniform circumferential airflow distribution at the outlets of each channel without significant flow deviation. This design can assist in flow control. and Optimize the outlet flow field to reduce dust accumulation caused by circumferential unevenness.

[0046] Typically, those skilled in the art, when designing impeller parameters for volute-less fans in rail transit, often fall into the inertia of prioritizing a single objective—design. At the time, the sole objective is often to "reduce inlet pressure loss," leading to the tendency to use the same angle setting and neglecting the compatibility between the airflow direction and the blade inlet profile, resulting in the easy formation of inlet vortex zones; design In pursuit of "high wind speed output," a larger angle is often used. While this increases the outlet velocity, it exacerbates abrupt velocity changes and negative pressure vortex zones, increasing the risk of dust accumulation. Previously, due to the constraints of "compact space layout," smaller wrap angles were commonly chosen in an attempt to adapt to the fan installation size by reducing the space occupied by the blade circumference. However, this resulted in frequent vortices within the flow channel due to the excessively short airflow guidance path. This application, however, breaks with these approaches and designs... The design focuses on "airflow direction adaptation," determining the angle by matching the incoming flow direction guided by the inlet neck channel, rather than simply pursuing minimal pressure loss, thus eliminating the inlet vortex zone at its source. Instead of adopting the "large angle, high wind speed" approach, a moderately acute angle setting is used to enhance diffusion capacity while ensuring a certain wind speed, avoiding sudden changes in flow velocity and negative pressure vortex zones; design Breaking through the limitations of "small space and small angle", it adopts a larger wrap angle and optimizes the airflow stability in the flow channel by extending the airflow guidance path. Although it occupies part of the circumferential space, it greatly reduces vortices. These settings all break through the conventional understanding of those skilled in the art and have significant non-obviousness.

[0047] This application optimizes the flow channel of the air inlet 10 and the geometric parameters of the impeller, thereby enhancing the diffusion capacity and work capacity of the flow channel formed by the front impeller plate 2 and the rear impeller plate 3. This results in smooth flow velocity changes without abrupt changes, reduced vortex formation, decreased outlet acceleration, low noise, and strong particle carrying capacity in the blade area, fundamentally changing problems such as severe dust accumulation and low operating efficiency.

[0048] In some preferred embodiments, the outlet edge diameter of the forefoot root is... The ratio of the blade's outer diameter D05 at the outlet of the impeller front disc 2 ranges from 0.48 to 0.493. This setting limits the relative position of the blades between the front and rear discs, reserving space for processing such as blade welding. If the ratio is too small, the overall size of the impeller and the entire machine will increase, which does not conform to the concept of "compact structure and small weight"; an increased overall impeller size, or being too close to the mounting bracket, will significantly increase dynamic and static interference, which does not conform to the concept of "high efficiency and low noise". When the ratio is 0.5, there is no processing allowance at the blade edges, making forming difficult and reducing strength. When the ratio is greater than 0.5, the blades extend beyond the front and rear discs, increasing the risk of accidents; without the constraint of the front disc, the blades' work capacity is reduced.

[0049] In some preferred embodiments, the number of the three-dimensional flow blades 4 is 7-15, preferably 9. When the number of blades is too small, the total working area of ​​the impeller decreases, requiring a larger diameter and a larger outlet angle to compensate for the design requirements. A large angle can easily cause flow separation, creating a hidden danger for dust accumulation, and large diameter blades have poor market competitiveness. When the number of blades is too large, the contact area between the airflow and the blades increases, leading to more adhering dust, and the flow channel is easily blocked, reducing the effective working area of ​​the fan.

[0050] To further optimize the flow field and dust accumulation prevention effect of the three-dimensional flow blade 4, this invention adds several serrations 41 to the outlet edge of the three-dimensional flow blade 4 (as shown in Figure 10), and optimizes the overlap parameters between the impeller and the air inlet 10. The specific design and function are as follows: The serration 41 at the outlet edge of the three-dimensional flow blade 4 needs to meet a specific dimensional ratio: This indicates the length of the outlet edge of the three-dimensional flow blade 4. This indicates the spacing between two adjacent saw teeth 41. Specifically, there are no saw teeth in the area one-third of the region closest to the outlet edge of the impeller front disc 2, and the saw teeth 41 are only arranged in the remaining two-thirds region; and the spacing between two adjacent saw teeth 41... The length of the outlet edge of the three-dimensional flow blade 4 The ratio ranges from 0.11 to 0.15, and the depth of the sawtooth 41 and the spacing between two adjacent sawtooth 41 are... Correspondingly, the serration depth refers to the distance from the apex of the serration protrusion to the bottom of the adjacent depression, along the length direction perpendicular to the exit edge of the three-dimensional flow blade 4 (i.e., perpendicular to...). The distance (in the direction of the line it lies on).

[0051] The core function of this design is to change the airflow pattern at the blade tail, suppressing dust accumulation at the source of the flow field: the blade tail is a high-incidence area of ​​negative pressure vortex (a major dust accumulation area). The serrated structure can "shred" the large-area stable vortex at the tail, decomposing it into small-scale, easily dissipated micro-vortices, disrupting the flow field conditions for continuous dust particle adhesion, and preventing dust from accumulating on the blade surface; at the same time, the serrated design will not significantly increase wind resistance, but can instead streamline the flow state of the outlet airflow, reduce airflow separation loss, and slightly improve the static pressure efficiency of the fan.

[0052] In some preferred embodiments, the overlap depth between the impeller and the air inlet 10 is 5-10 mm, and the overlap gap is 1-4 mm. The overlap depth refers to the axial length along the fan rotation axis (Z-axis, where airflow flows from the negative direction to the positive direction of the Z-axis) by which the impeller (specifically, the edge area of ​​the impeller front disc near the air inlet) and the air inlet (the outlet end of the air inlet neck section) overlap. The overlap gap refers to the minimum gap width between the impeller (usually the edge of the impeller front disc) and the air inlet (the inner wall of the air inlet neck section) in the radial direction perpendicular to the Z-axis (i.e., the circumferential direction). The overlap depth and overlap gap are the "core matching parameters" for the assembly of the impeller and the air inlet: the overlap depth determines the axial overlap range, ensuring "no leakage and stable transition" of the airflow; the overlap gap controls the size of the radial gap, ensuring "no friction and minimal eddies". The two work together to ensure smooth flow in the connection area between the air inlet and the impeller, which avoids efficiency loss caused by airflow leakage and reduces dust accumulation caused by gap vortices, laying the foundation for subsequent blade vortex breaking and dust accumulation prevention design.

[0053] Through the above optimized design, such as Figure 11a , Figure 11b As shown, after modification, the airflow separation phenomenon on the back of the three-dimensional flow blade 4 near the impeller front disk 2 completely disappeared, the recirculation zone was almost undetectable, and the velocity change gradient between the two blades was gentle, the flow field distribution was uniform, the airflow velocity was significantly improved, and the ability to carry dust particles was greatly enhanced. The anti-dust accumulation and flow control effects were verified from the flow field level.

[0054] The following optimized effects were obtained from the performance test and sandstorm test results: Under the same test conditions, the dust accumulation decreased from 709 grams to 99 grams, a reduction rate of 86%, significantly reducing the damage to the fan caused by dust adhesion; power consumption decreased by 15.6%, resulting in a significant reduction in energy loss; static pressure efficiency increased by 7.8%, improving airflow energy conversion efficiency; and aerodynamic noise decreased by 2.4 dB, effectively controlling noise pollution. Therefore, it simultaneously achieves the beneficial effects of reducing energy consumption, significantly reducing maintenance costs, extending fan life, and reducing noise pollution.

[0055] In summary, by designing the blade outlet serrations and optimizing the overlap parameters between the impeller and the air inlet, this invention achieves multiple objectives of "preventing dust accumulation, reducing energy consumption, improving efficiency, and reducing noise," ultimately resulting in the beneficial effects of reducing equipment maintenance costs, extending the service life of the fan, and improving the reliability of the rail transit ventilation system.

[0056] In some preferred embodiments, such as Figure 12 As shown, the air inlet 10 consists of an air inlet flange 101 and an air inlet neck section 102. Along the circumferential direction of the air inlet flange 101, there are axially penetrating large-diameter through holes 103 and small-diameter through holes 104. The small-diameter through holes 104 are used to connect the air inlet insulation plate 13 to the air inlet 10. The large-diameter through holes 103 are used to avoid the air inlet insulation plate 13 and its connecting parts, and to prevent the connecting parts from contacting the flange. Correspondingly, the air inlet mounting panel 1 is also provided with large-diameter through holes 103 to avoid contact between the connecting parts and the air inlet mounting panel 1, and to ensure the insulation effect.

[0057] In some preferred embodiments, such as Figure 1 , Figure 2 As shown, the volute-less fan also includes a motor connecting bracket 7, a panel reinforcement frame 9, a panel sealing gasket 14, a panel insulating gasket 15, and a connector 16. The motor 6 is mounted on one side of the fan mounting panel 8 via the motor connecting bracket 7 and the connector 16. The panel insulating gasket 15 is sandwiched at the connection point between the motor 6 and the fan mounting panel 8. The fan mounting panel 8 integrates the panel reinforcement frame 9 and the panel sealing gasket 14 to improve structural strength and sealing performance.

[0058] In some preferred embodiments, the volute-less fan further includes an air inlet sealing gasket 12 and an air inlet insulating plate 13. The air inlet 10 is integrated into the air inlet mounting surface. The air inlet mounting panel 1 is provided with an air inlet sealing gasket 12. The sealing surface of the air inlet 10 is located on the air inlet side of the air inlet mounting panel 1, and the air inlet mounting panel 1 is mounted on the air inlet insulating plate 13. The air inlet insulating plate 13 blocks the direct contact between the air inlet 10 and the air inlet mounting panel 1, thereby achieving an insulating effect.

[0059] In some preferred embodiments, the air inlet mounting panel 1 and the fan mounting panel 8 are fixedly connected by an air inlet connecting bracket 11, and the air inlet connecting bracket 11 is arranged on the outside of the impeller to stably support the air inlet mounting panel 1 and the fan mounting panel 8, ensuring the installation distance and coaxiality between the two panels, and avoiding panel deformation or relative displacement due to vibration; at the same time, its outer arrangement can avoid the core flow channel area around the impeller, not interfere with the airflow, prevent eddies or airflow obstruction in the flow channel, and take into account both structural stability and flow field smoothness.

[0060] In some preferred embodiments, the volute-less fan further includes a bushing 5, and the impeller is connected to the drive end (motor shaft) of the motor 6 through the bushing 5 to realize power transmission.

[0061] The above-mentioned structure, formed by adding an air inlet insulating plate 13, a panel insulating pad 15, and bolt insulating sleeves for connectors 16, provides multiple electrical isolation functions. Its core function is to block stray current corrosion and prevent the safety risks of motor leakage. In rail transit systems, unexpected stray currents (leakage currents) are generated during train operation. If this current directly contacts the metal components of the fan (such as the air inlet 10, impeller, motor 6 housing, etc.), it will cause electrochemical corrosion and significantly shorten the service life of the components. The insulating components can effectively block the conduction path of stray currents and prevent metal components from being corroded. At the same time, the insulating structure can achieve electrical isolation and prevent leakage current inside the motor 6 from being conducted to the track or car body, thus ensuring passenger safety and preventing leakage current from damaging other equipment in the rail transit system.

[0062] Example 1 The ratio of the air inlet diameter D01 to the air outlet diameter D02 of the air inlet 10 is set to 1.02. The minimum diameter of the air inlet 10 is the throat diameter D03. The ratio of the throat diameter D03 to the air outlet diameter D02 of the air inlet 10 is set to 0.92. The ratio of the throat height H02 to the air inlet height H01 is set to 0.35.

[0063] The impeller front disc 2 is composed of a front disc arc segment 201 and a front disc straight segment 202. The front disc arc segment 201 and the front disc straight segment 202 are tangent. The radius of the front disc arc segment 201 is 40mm, and the forming angle of the front disc straight segment 202 is... The inlet projection diameter D04 of the impeller front disc 2 is 0.65, and the ratio of the outlet outer diameter D05 of the impeller front disc 2 to the outlet outer diameter D05 of the impeller front disc 2 is 0.3 along the Z-axis direction.

[0064] In some preferred embodiments, along the Z-axis, the impeller rear disk 3 is composed of a first straight segment 301, a first arc segment 304, a second straight segment 302, and a second arc segment 303 connected in sequence. Both arc segments of the impeller rear disk 3 are tangent to their adjacent straight segments. The radius of the second arc segment 303 is 150mm; the radius of the first arc segment 304 is 10mm; and the forming angle of the second straight segment 302 is... The angle is 15°; the ratio of the center diameter D06 of the rear disc center hole of the impeller rear disc 3 to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 0.3; the ratio of the outer edge diameter D07 of the impeller rear disc 3 to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 1; the ratio of the height H06 of the impeller rear disc 3 to the height H07 of the impeller is 0.4. The ratio of the height H07 of the impeller to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 0.21.

[0065] The specific design parameters of the impeller are as follows: In this embodiment, the performance meets the design requirements, power consumption is reduced by 10%, and the flow field inside the impeller is as follows: Figure 13a As shown, near the front plate on the back of the blades, there is no backflow zone before the airflow exits the impeller, resulting in smooth overall flow. The velocity direction is consistent with the main flow direction, making it difficult for dust to settle. For example... Figure 13b As shown, near the impeller back plate, the airflow does not separate on the back of the blades from the moment it enters them, resulting in good flow and preventing large-scale deposition of sand and dust.

[0066] Example 2 The ratio of the air inlet diameter D01 to the air outlet diameter D02 of the air inlet 10 is set to 1.6. The minimum diameter of the air inlet 10 is the throat diameter D03. The ratio of the throat diameter D03 to the air outlet diameter D02 of the air inlet 10 is set to 0.95. The ratio of the throat height H02 to the air inlet height H01 is set to 0.5.

[0067] The impeller front disc 2 is composed of a front disc arc segment 201 and a front disc straight segment 202. The front disc arc segment 201 and the front disc straight segment 202 are tangent. The radius of the front disc arc segment 201 is 80mm, and the forming angle of the front disc straight segment 202 is... The angle is 25°. The ratio of the inlet projection diameter D04 of the impeller front disk 2 to the outlet outer diameter D05 of the impeller front disk 2 is 0.8. Along the Z-axis direction, the ratio of the height H05 of the impeller front disk 2 to the height H07 of the impeller is 0.6.

[0068] In some preferred embodiments, along the Z-axis, the impeller rear disk 3 is composed of a first straight segment 301, a first arc segment 304, a second straight segment 302, and a second arc segment 303 connected in sequence. Both arc segments of the impeller rear disk 3 are tangent to their adjacent straight segments. The radius of the second arc segment 303 is 450 mm; the radius of the first arc segment 304 is 50 mm; and the forming angle of the second straight segment 302 is... The angle is 35°; the ratio of the center diameter D06 of the rear disc center hole of the impeller rear disc 3 to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 0.5; the ratio of the outer edge diameter D07 of the impeller rear disc 3 to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 0.8; the ratio of the height H06 of the impeller rear disc 3 to the height H07 of the impeller is 0.75; the ratio of the height H07 of the impeller to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 0.35.

[0069] The specific design parameters of the impeller are as follows: In this embodiment, the performance meets the design requirements, power consumption is reduced by 9%, and the flow field inside the impeller is as follows: Figure 14a As shown, near the front plate on the back of the blades, there is no backflow zone before the airflow exits the impeller, resulting in smooth overall flow. The velocity direction is consistent with the main flow direction, making it difficult for dust to settle. For example... Figure 14b As shown, near the impeller back plate, the airflow does not separate on the back of the blades from the moment it enters them, resulting in good flow and preventing large-scale deposition of sand and dust.

[0070] Comparative Example In some embodiments, the air inlet and front disc profile adopt parameters within a preferred range, and different rear discs and blades are used.

[0071] Along the Z-axis, the impeller rear disk 3 is composed of a first straight segment 301, a first arc segment 304, a second straight segment 302, a second arc segment 303, and a third straight segment tangent to them, connected in sequence. Both arc segments of the impeller rear disk 3 are tangent to their adjacent straight segments. The radius of the second arc segment 303 is 21 mm; the radius of the first arc segment 304 is 21 mm; the forming angle of the second straight segment 302 is... The angle is 64.7°; the ratio of the center diameter D06 of the rear disc center hole of the impeller rear disc 3 to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 0.21; the ratio of the outer edge diameter D07 of the impeller rear disc 3 to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 0.99; the ratio of the height H06 of the impeller rear disc 3 to the height H07 of the impeller is 0.69. The ratio of the height H07 of the impeller to the outlet outer diameter D05 of the front disc outer edge of the impeller front disc 2 is 0.28. The main parameter of the rear disc is the forming angle. The diameter D06 is not within the preferred parameter range.

[0072] The specific design parameters of the impeller are as follows: In this embodiment, the fan performance meets the design requirements, but the efficiency is low, the power consumption is high, and the flow field inside the impeller is as follows: Figure 15a As shown, near the front disk on the back of the blade, a large area of ​​backflow occurs before the airflow exits the impeller. In this area, the gas flow is turbulent, the velocity suddenly decreases, and the velocity direction is inconsistent with the main flow direction, making it a major area for dust deposition. Figure 15b As shown, near the impeller back plate, the airflow begins to separate on the back of the blade from the moment it enters the blade. The separation occurs on the back of the blade, which accounts for about 2 / 3 of the total blade length. The velocity in this area is low, and the dust-carrying capacity is insufficient, so sand and dust are deposited here.

[0073] The specific embodiments of this application have been described in detail above. For those skilled in the art, several improvements and modifications can be made to this application without departing from the principle of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. An impeller comprising an impeller front disc (2), an impeller rear disc (3), and a plurality of three-dimensional flow blades (4) connected between the impeller front disc (2) and the impeller rear disc (3), characterized in that: Along the Z-axis, the space between the two profiles of the impeller front disc (2) and the impeller rear disc (3) facing each other is divided into four small channels, forming five different small channel lines, denoted as a, b, c, d, and e, where a is the front disc profile and e is the rear disc profile. The intersection of these five lines with the same three-dimensional blade (4) is... , , , , , , , , , The projection lines i on the cross section perpendicular to the Z-axis are denoted as follows: , , , , ; The specific design parameter range is as follows: The curved surface connecting the three-dimensional flow blade (4) to the impeller front disk (2) is the front blade root, and the outlet diameter of the front blade root is the same as the blade outlet diameter. The straight-line distance from the endpoint of projection line i at the outlet edge to the center of the fan's rotating shaft is the outlet projection diameter. The distance from the inlet endpoint of projection line i to the projection axis is the inlet projection diameter. The angle between the tangent at the endpoint of projection line i and the tangent of the arc from the endpoint to the projection axis is the projection entrance angle. The angle between the tangent to projection line i at its endpoint at the exit edge and the tangent to the arc from its endpoint to the projection axis is the projection exit angle. .

2. The impeller according to claim 1, characterized in that: Along the airflow direction from the inlet to the outlet, the angle between the circumferential angle difference formed by the i-th projection line and its adjacent projection line at the corresponding radii on the outlet side is the misalignment angle. , , , , misalignment angle The design parameter range is 0-6, 0-5, 0-4, 0-3.

3. The impeller according to claim 1, characterized in that: The impeller front disc (2) is composed of a tangent front disc arc segment (201) and a front disc straight segment (202), wherein the forming angle of the front disc straight segment (202) is... The range is 0°-25°. The ratio of the inlet projection diameter D04 of the impeller front plate (2) to the outlet outer diameter D05 of the impeller front plate (2) is 0.65-0.

8. Along the Z-axis direction, the ratio of the height H05 of the impeller front plate (2) to the height H07 of the impeller is 0.3-0.

6.

4. The impeller according to claim 1, characterized in that: The impeller rear disc (3) is composed of a first straight segment (301), a first arc segment (304), a second straight segment (302), and a second arc segment (303) connected in sequence. The forming angle of the second straight segment (302) is... The range is 15°-35°; The ratio of the center diameter D06 of the rear disc of the impeller rear disc (3) to the outlet outer diameter D05 of the front disc of the impeller front disc (2) is in the range of 0.3-0.5; the ratio of the outer diameter D07 of the rear disc of the impeller rear disc (3) to the outlet outer diameter D05 of the front disc of the impeller front disc (2) is in the range of 0.8-1; the ratio of the height H06 of the impeller rear disc (3) to the height H07 of the impeller is in the range of 0.4-0.

75. The ratio of the height H07 of the impeller to the outlet outer diameter D05 of the outer edge of the front plate of the impeller front plate (2) is in the range of 0.21-0.

35.

5. The impeller according to claim 1, characterized in that: The curved surface connecting the three-dimensional flow blade (4) to the impeller front disk (2) is the front blade root, and the outlet edge diameter of the front blade root is... The ratio of the outer diameter D05 of the impeller front disc (2) to the outlet diameter D05 ranges from 0.48 to 0.

493.

6. The impeller according to claim 1, characterized in that: The number of the three-dimensional flow blades (4) is 7-15.

7. The impeller according to claim 1, characterized in that: The exit edge of the three-dimensional flow blade (4) is provided with several serrations (41) to... This indicates the length of the exit edge of the three-dimensional flow blade (4). The spacing between two adjacent saw teeth (41) is specified, wherein there are no saw teeth in one-third of the area near the outlet edge of the impeller front disc (2), and the saw teeth (41) are arranged only in the remaining two-thirds of the area, and the spacing between two adjacent saw teeth (41) is specified. The length of the outlet edge of the three-dimensional flow blade (4) The ratio ranges from 0.11 to 0.

15.

8. A volute-less fan, comprising an impeller as described in any one of claims 1 to 7, and further comprising an air inlet mounting panel (1), a motor (6), and a fan mounting panel (8) connected along the vertical rotation axis Z-axis, characterized in that: The air inlet mounting panel (1) is provided with an air inlet (10), and the air inlet (10) is connected to one end of the impeller to form a gradually expanding airflow channel; The air inlet (10) includes an air inlet neck section (102), which is composed of a circular arc section (105) and a straight line section (106) rotated together, and the straight line section (106) is tangent to the circular arc section (105); The ratio of the air inlet diameter D01 of the air inlet (10) to the air outlet diameter D02 of the air inlet (10) is in the range of 1.02-1.

6.

9. The impeller of the volute-less fan according to claim 8, characterized in that: The minimum diameter of the air inlet (10) is the throat diameter D03. The ratio of the throat diameter D03 of the air inlet (10) to the air outlet diameter D02 of the air inlet (10) is in the range of 0.92-0.

95. The ratio of the throat height H02 to the air inlet height H01 is in the range of 0.35-0.

5.

10. The volute-less fan according to claim 8, characterized in that: The overlap depth between the impeller front plate (2) and the air inlet (10) is 5-10mm, and the overlap gap is 1-4mm.

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