CN114109897A

CN114109897A - Wind wheel, centrifugal fan and clothes drying equipment

Info

Publication number: CN114109897A
Application number: CN202010876844.8A
Authority: CN
Inventors: 汪坤; 李磊; 谢邦明; 邓德喜; 宁喆
Original assignee: Wuxi Little Swan Electric Co Ltd
Current assignee: Wuxi Little Swan Electric Co Ltd
Priority date: 2020-08-27
Filing date: 2020-08-27
Publication date: 2022-03-01

Abstract

The embodiment of the application provides a wind wheel, centrifugal fan and clothes drying equipment, the wind wheel includes the end disc and sets up in a plurality of blades of end disc one side, and a plurality of blades are around the rotation center line interval arrangement of wind wheel in order to form annular structure, and the one end that the end disc was kept away from to annular structure is the inlet end, and the clearance between two adjacent blades is the air-out passageway, from the leading edge to the direction at trailing edge of blade, the thickness of blade reduces gradually. The wind wheel of this application embodiment, because the thickness of blade reduces gradually, make the flow area of air-out passageway increase gradually along airflow flow direction, that is to say, the air-out passageway forms a diffusion wind channel, so can reduce wind speed in the air-out passageway, reduce the frictional force on air current and blade surface, reduce the loss of pressure of air-out passageway, reduce the adverse pressure gradient in the air-out passageway, thereby reduce the blade trailing edge and produce the possibility of flow separation, reduce air current energy loss and reduce aerodynamic noise.

Description

Wind wheel, centrifugal fan and clothes drying equipment

Technical Field

The application relates to the technical field of fans, in particular to a wind wheel, a centrifugal fan and clothes drying equipment.

Background

Taking a clothes dryer as an example, the pneumatic noise caused by the rotation of the wind wheel is a main source of the noise of the clothes dryer, and the problem of complaint of the noise generated by the wind wheel in the clothes dryer is increased gradually. In the related art, the blades of the wind turbine are mainly designed to have the same thickness, that is, the thickness of the blades from the leading edge to the trailing edge is the same, so that the pressure loss in the flow channel is large, and further, the large aerodynamic noise is generated.

Disclosure of Invention

In view of the above, embodiments of the present application are expected to provide a wind wheel, a centrifugal fan and a clothes drying apparatus, which reduce pressure loss and pneumatic noise.

In order to reach above-mentioned purpose, this application embodiment a wind wheel for centrifugal fan, wind wheel include the end disc and set up in a plurality of blades of end disc one side, a plurality of blades center on the center line of rotation interval arrangement of wind wheel is in order to form annular structure, annular structure keeps away from the one end of end disc is the inlet end, adjacent two clearance between the blade is the air-out passageway, follows the leading edge to the direction at trailing edge of blade, the thickness of blade reduces gradually.

In some embodiments, the profile of the blade comprises a first arc on the windward side and a second arc on the leeward side, the first arc and the second arc being eccentrically disposed.

In some embodiments, the ratio of the inner diameter to the outer diameter of the annular structure is 0.78 to 0.84.

In some embodiments, the front edge of one end of the blade, which is far away from the end disc, is provided with an arc transition area, and the ratio of the radius of the arc transition area to the width of the wind wheel along the axial direction is 0.05-0.08.

In some embodiments, the blade has a thickness of 1mm to 2 mm.

In some embodiments, the inlet angle of the blade is between 80 ° and 96 °.

In some embodiments, the exit angle of the blade is 135 ° to 150 °.

In some embodiments, the rotor includes an end ring connected to an end of the annular structure facing away from the end disk; the circumferential outer surface of the end ring is flush with the outer surface of the blade along the circumferential direction of the wind wheel; the end surfaces of the blades and the end surfaces of the end rings are flush in the axial direction of the wind wheel.

A second aspect of an embodiment of the present application provides a centrifugal fan, including a volute and the wind wheel of any of the above embodiments, the wind wheel is rotatably disposed in the volute.

A third aspect of the embodiments of the present application provides a clothes drying apparatus, comprising the centrifugal fan, the clothes drying airflow channel and the clothes treatment cavity, wherein the centrifugal fan is disposed on the clothes drying airflow channel to generate directional movement of air in the clothes drying airflow channel.

The wind wheel of this application embodiment, because the thickness of blade reduces gradually, make the flow area of air-out passageway increase gradually along airflow flow direction, that is to say, the air-out passageway forms a diffusion wind channel, so can reduce wind speed in the air-out passageway, reduce the frictional force on air current and blade surface, reduce the loss of pressure of air-out passageway, reduce the adverse pressure gradient in the air-out passageway, thereby reduce the blade trailing edge and produce the possibility of flow separation, reduce air current energy loss and reduce aerodynamic noise.

Drawings

FIG. 1 is a schematic view of a wind turbine according to an embodiment of the present application;

FIG. 2 is a schematic view from another perspective of FIG. 1, wherein the dashed lines and arrows indicate the direction of airflow;

FIG. 3 is a right side view of FIG. 2;

FIG. 4 is a schematic view of FIG. 2 with a portion of the structure omitted;

FIG. 5 is a schematic view of a blade profile fit of an embodiment of the present application, wherein only one blade is shown;

fig. 6 is a partially enlarged schematic view of the blade of fig. 5.

Description of the reference numerals

An end disk 10; an end ring 20; a blade 30; an air outlet channel 30 a; a circular arc transition zone 30 b; a first profile 301; a second profile 302; a leading edge 30e and a trailing edge 30f

Detailed Description

It should be noted that, in the present application, technical features in examples and embodiments may be combined with each other without conflict, and the detailed description in the specific embodiment should be understood as an explanation of the gist of the present application and should not be construed as an improper limitation to the present application.

The orientation or positional relationship in the description of the embodiments of the present application is based on that shown in the drawings, it being understood that these positional terms are merely for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the present application.

The embodiment of the application provides a wind wheel for a centrifugal fan. Referring to fig. 1, the wind wheel includes an end disc 10 and a plurality of blades 30 disposed on one side of the end disc 10, the plurality of blades 30 are spaced around a rotation center line (simplified to point O in fig. 4 and 5) of the wind wheel to form an annular structure, one end of the annular structure away from the end disc 10 is an air inlet end, a gap between two adjacent blades 30 is an air outlet channel 30a, and referring to fig. 6, the thickness of the blades 30 is gradually reduced from a front edge 30e to a rear edge 30f of the blades 30.

The working principle of the wind wheel is as follows: the gas flow enters the middle region of the ring structure along the end of the ring structure facing away from the end disc 10, e.g. the gas flow enters the ring structure along the left in fig. 3; when the wind wheel rotates at a high speed, the air flow in each air outlet channel 30a is thrown out of the wind wheel at a high speed, so that negative pressure is formed in the middle area of the annular structure, outside air is sucked into the wind wheel under the action of the negative pressure, and then is thrown out of the wind wheel, and the circulation is performed. That is, the airflow enters the wind wheel along the axial direction of the wind wheel and is discharged along the circumferential direction of the wind wheel.

It should be noted that, during the rotation of the wind wheel, the airflow flows from the low pressure place to the high pressure place in the wind outlet channel 30a, that is, the airflow has a counter pressure gradient in the wind outlet channel 30 a. For the boundary layer of the wall surface of the blade 30, if there is a backpressure gradient in the main flow direction, the main flow outside the boundary layer can increase the pressure with decreasing kinetic energy, but in the boundary layer, the flow has lost part of the kinetic energy due to viscous drag, so under the backpressure gradient, assuming that the normal pressure gradient along the wall surface of the blade 30 is zero, the flow velocity in the boundary layer decreases at a greater rate than outside the boundary layer, and as a result, its velocity profile becomes thinner and thinner in the flow direction. Meanwhile, the frictional stress on the wall surface of the blade 30 is also reduced along with the increase of the backpressure gradient, when the pressure gradient is large enough, the kinetic energy of the flowing air flow near the wall surface of the blade 30 is not enough to provide the required pressure, at this time, the fluid flowing near the wall surface of the blade 30 flows in the reverse direction, the main flow far away from the wall surface of the blade 30 still flows in the original direction, and the phenomenon of flow separation occurs, so that the collision friction between the air flows and the wall surface of the blade 30 is increased, and the large air flow energy loss and the large aerodynamic noise are formed.

The wind wheel of the embodiment of the application, because the thickness d of blade 30 reduces gradually, make the flow area of air-out passageway 30a increase gradually along airflow flow direction, that is to say, air-out passageway 30a forms a diffusion wind channel, so can reduce wind speed in the air-out passageway 30a, reduce the frictional force on air current and blade 30 surface, reduce the pressure loss of air-out passageway 30a, reduce the adverse pressure gradient in the air-out passageway 30a, thereby reduce the trailing edge 30f of blade 30d and produce the possibility of flow separation, reduce the air current energy loss and reduce aerodynamic noise.

In one embodiment, referring to FIG. 4, the inner diameter r of the ring structure₁And outer diameter r₂The ratio of (r) to (b) is 0.78 to 0.84₁/r₂0.78-0.84. The inner diameter r of the annular structure₁The outer diameter r of the ring structure is the distance between the leading edge 30e of the blade 30 and the rotation center line of the wind wheel 30₂The distance between the trailing edge 30f of the blade 30 and the rotational center line of the rotor 30. Book (I)The ratio of the inner diameter to the outer diameter of the applied embodiment is larger than that of the wind wheel in the related art. For example, at the inner diameter r of the ring structure₁Under the same condition, the outer diameter of the annular structure of the embodiment is smaller, and under the condition of the same rotating speed, the linear velocity of the trailing edge 30f of the blade 30d is smaller, so that the stress borne by the trailing edge 30f of the blade 30 is reduced, and the structural safety of the blade 30 is improved. For example, under the condition that the outer diameters of the annular structures are the same, the inner diameter of the annular structure of the embodiment is larger, so that the air inlet area of the wind wheel is larger, and the flow velocity of the airflow is relatively smaller under the same flow rate, so that the pressure loss in the air outlet channel 30a is small.

It can be understood that the specific implementation manners of the embodiments of the present application, which provide the ratio between the inner diameter and the outer diameter, include the following three types: first, only the size of the outer diameter is reduced on the basis of the size of the wind wheel of the related art; second, only the size of the inner diameter is increased on the basis of the size of the wind wheel of the related art; thirdly, based on the size of the wind wheel in the related art, the size of the inner diameter is increased, and the size of the outer diameter is decreased, in this embodiment, the inner diameter is larger, the outer diameter is smaller, the wind inlet area of the wind wheel is increased, and the linear velocity of the rear edge 30f of the blade 30 is decreased.

In one embodiment, the thickness d of the blade 30 is 1mm to 2mm, such as 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, and the like. That is, the thickness range of the entire blade 30 at any position is in the range of 1mm to 2 mm. It should be noted that, if the thickness of the blade 30 is too thin, the structural strength of the blade 30 is poor, and the blade 30 is easily torn; if the thickness of the blade 30 is too thick, the weight of the wind wheel is increased, which not only increases the manufacturing cost but also reduces the flow area of the wind outlet channel 30 a. Therefore, in the embodiment of the present invention, the thickness of the blade 30 is controlled within the range of 1mm to 2mm, and the structural strength and the airflow flow area can be satisfied at the same time.

Referring to fig. 6, the profile of the blade 30 includes a first profile 301 on the windward side and a second profile 302 on the leeward side. The profile of the blade refers to a line corresponding to the profile of the blade.

In one embodiment, referring to fig. 6, the inlet angle θ of the blade 30 is 80-96 °. Specifically, the tangent line at the leading edge 30e of the first profile 301 of the blade 30 is a straight line DB, the tangent line at D of the inner circle of the annular structure is DN, and the included angle between the straight line DB and the straight line DN on the convex side of the first profile 301 is the inlet angle θ.

In one embodiment, referring to FIG. 6, the exit angle of the blade 30 is 135-150, such as 135, 136, 140, 145, 147, 150, etc. It should be noted that a tangent of the outer diameter circle C2 at the trailing edge 30f of the first profile 301 of the vane 30 is FK, and an included angle between the tangent FK at the trailing edge 30f of the first profile 301 of the vane 30 and a straight line on the convex side of the first profile 301 is the exit angle β. Under the range of the outlet angle beta, the wind wheel can obtain higher isentropic efficiency and higher static pressure ratio.

In one embodiment, referring to fig. 1, a circular arc transition area 30b is disposed at a front edge 30e of an end of the blade 30 facing away from the end disk 10, and a ratio of a radius of the circular arc transition area 30b to a width L of the wind wheel along the axial direction is 0.05-0.08. In this embodiment, circular arc transition zone 30b can increase the air inlet area of wind wheel, reduces the air intake resistance of wind wheel, guarantees that more gas can get into the one end that the wind wheel is close to end plate 10 from the inlet end of wind wheel, improves wind wheel efficiency, the lightweight design of the wind wheel of being convenient for simultaneously, and the lightweight design of wind wheel not only can reduce manufacturing cost, can also improve centrifugal fan's work efficiency.

It can be understood that the radius of the arc transition area 30b cannot be too large, otherwise, the working capacity of the blade 30 is affected, and therefore, in the embodiment of the present application, the ratio range of the two is designed to be 0.05-0.08, and the air inlet area and the working capacity of the blade 30 can be considered at the same time. Illustratively, the radius of the arc transition zone 30b is 3mm, and the width L of the rotor in the axial direction is 44.776, with a ratio of 0.067.

The specific shape of the first profile 301 is not limited, and may be, for example, a plurality of circular arcs, or a circular arc and a straight line segment. Similarly, the specific shape of the second profile 302 is not limited, and may be, for example, a plurality of circular arcs, or a circular arc and a straight line segment.

Illustratively, in an embodiment, the first profile 301 and the second profile 302 are circular arcs, that is, the profile of the blade 30 includes a first circular arc on the windward side and a second circular arc on the leeward side, and the first circular arc and the second circular arc are eccentrically arranged. Specifically, the first mold line 301 corresponds to a first circle center, the second mold line 302 corresponds to a second circle center, and the first circle center and the second circle center are eccentrically arranged. In this embodiment, the first mold line 301 and the second mold line 302 are generated by circular arcs, and the mold lines are simple and convenient for mold manufacturing and molding.

In one embodiment, referring to fig. 1, the wind wheel includes an end ring 20, and the end ring 20 is connected to an end of the annular structure facing away from the end disc 10, that is, an end of each blade 30 facing away from the end disc 10 is connected to the end ring 20. The end ring 20 can increase the rigidity of the vane 30, prevent the vane 30 from being in a cantilever supporting structure, improve the stress condition of the vane 30, and prolong the service life of the vane 30.

In one embodiment, referring to fig. 2 and 3, the circumferential outer surface of the end ring 20 is flush with the outer surface of the blades 30 in the circumferential direction of the wind turbine; in the axial direction of the wind wheel, the end faces of the end rings 20 are flush with the end faces of the blades 30. Note that, in fig. 2, a part of the vane 30 radially outward is shielded by the end ring 20. In this embodiment, the end rings 20 do not increase the external dimension of the wind wheel, and also make the external appearance of the wind wheel neat and beautiful.

Note that, the end face of the end ring 20 is flush with the end face of the vane 30, which means that the area of the end face of the vane 30, which is not connected to the end ring 30, is flush with the end face of the end ring 30.

The fitting method of the profile of the blade of the wind turbine is not limited, and may be obtained according to any suitable fitting method. Exemplarily, in an embodiment, referring to fig. 5 and 6, the method for fitting the profile of the blade of the wind turbine includes the following steps.

S1: setting the center O of the wind wheel, taking the center O as the center of a circle and r as the center of a circle₁Drawing the inner diameter circle C1 of the wind wheel for radius, with r₂The outer diameter circle C2 of the rotor is drawn for the radius. The inner diameter circle C1 and the outer diameter circle C2 are concentric circles. The inner circle C1 is an inner circle of the annular structure, and the outer circle C2 is an outer circle of the annular structure.

S2: a straight line OA is drawn through center O and intersects inner radius C1 at point D. The length of the straight line OA is not limited as long as the straight line OA can intersect the inner diameter circle C1. In some embodiments, the length of the line OA may be the same as the length of the line OD, i.e., points a and D coincide.

S3: determining a circle center point E, drawing an arc C3 by taking the circle center point E as a circle center and taking R1 as a radius, wherein the arc C3 intersects the inner diameter circle C1 at a point D and intersects the outer diameter circle C2 at a point F, and an arc DF is a first profile 301 of the blade 30.

S5: determining a circle center G point, wherein the circle center G point and the circle center E point are eccentrically arranged, namely the G point and the E point are not overlapped; an arc C4 is drawn by taking a circle center point G as a circle center and taking R2 as a radius, the arc C4 intersects the inner diameter circle C1 at a point H and intersects the outer diameter circle C2 at a point I, and an arc HI is a second profile line 302 of the blade 30.

The profile DFIH is the profile of the blade 30.

It will be appreciated that the above steps may be repeated to sequentially depict the remaining blades, or the depicted blades may be rotationally duplicated to depict the remaining blades based on the central angle corresponding to the spacing between adjacent blades.

The above manner of determining the circle center E point is not limited, and in an exemplary embodiment, the step of determining the circle center E point specifically includes: drawing a tangent line DB of the first profile 301 according to the entrance angle theta, taking a point D as a starting point, and making a perpendicular line DE of the tangent line DB, wherein a point which is away from the point D by R1 on the perpendicular line DE is a circle center point E. It should be noted that, according to the perpendicular DE, there are two points which are separated from the point D by R1, and it is necessary to determine which point is selected as the point E according to the actual turning direction of the wind wheel. For example, taking figure 6 as an example, if the rotor needs to be turned counterclockwise, point E will be to the left of point D. If the rotor needs to be turned clockwise, point E will be to the right of point D.

It should be noted that R1 determines the exit angle of blade 30, and adjusting the size of R1 can change the size of exit angle β to keep exit angle β in a proper range.

The above determining manner of determining the circle center G point is not limited, and in an exemplary embodiment, the step of determining the circle center G point specifically includes: and taking the point E as a starting point, drawing a vertical line EG of the line segment DE, and taking the point E as the starting point and a point which is away from the point E by h1 as a circle center G point on the vertical line EG. It should be noted that, on the perpendicular line EG, there are two points separated from the point E by the distance h1, wherein one of the points will cause the thickness of the blade 30 to gradually increase from the leading edge to the trailing edge, and the point above the point E should be discarded, for example, as shown in fig. 6, and the point below the point E should be used as the center G point, so as to satisfy the requirement that the thickness of the blade 30 gradually decreases from the leading edge to the trailing edge.

It should be noted that the distances h1 and R2 together determine the thickness of the blade 30.

The embodiment of the application further provides a centrifugal fan, which comprises a volute and any one of the wind wheels, wherein the wind wheel is rotatably arranged in the volute.

The centrifugal fan of the embodiment of the application can be used in any appropriate occasions. Illustratively, the centrifugal fan is used for a clothes drying device as an example for description.

The embodiment of the application provides a clothes drying device, and clothes drying device includes the centrifugal fan of any one of the above-mentioned embodiments, the clothing air current passageway and the clothing process chamber that communicate each other, and the clothing of treating drying can be placed in the clothing process chamber, and centrifugal fan sets up on clothing air current passageway so that the air in the clothing air current passageway produces directional motion, in order to take away the humid air in the clothing process chamber.

In some embodiments, a heater may be further disposed on the clothes drying airflow channel to dry the clothes through the hot airflow.

The drying device may be a clothes dryer or an all-in-one washer dryer. The drying device may be a pulsator type drying device, a drum type drying device, a cabinet type dryer, or the like, which is not limited herein.

The various embodiments/implementations provided herein may be combined with each other without contradiction.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A wind wheel for a centrifugal fan, comprising:

an end disc (10);

set up in a plurality of blades (30) of end disc (10) one side, a plurality of blades (30) centers on the rotation center line interval arrangement of wind wheel is in order to form annular structure, annular structure keeps away from the one end of end disc (10) is the inlet end, adjacent two clearance between blade (30) is air-out passageway (30a), follows the leading edge to the direction of trailing edge of blade (30), the thickness of blade (30) reduces gradually.

2. The wind rotor according to claim 1, characterized in that the profile of the blade (30) comprises a first arc on the windward side and a second arc on the leeward side, the first and second arcs being eccentrically arranged.

3. The wind turbine of claim 1, wherein the ratio of the inner diameter to the outer diameter of the ring-shaped structure is 0.78-0.84.

4. The wind wheel according to claim 1, characterized in that the front edge of the end of the blade (30) facing away from the end disc (10) is provided with a circular arc transition area (30b), and the ratio of the radius of the circular arc transition area (30b) to the width of the wind wheel along the axial direction is 0.05-0.08.

5. The wind rotor according to claim 1, characterized in that the thickness of the blades (30) is 1 mm-2 mm.

6. The wind wheel according to claim 1, characterized in that the inlet angle of the blades (30) is 80-96 °.

7. The wind rotor according to claim 1, characterized in that the exit angle of the blades (30) is 135-150 °.

8. The wind wheel according to claim 1, characterized in that the wind wheel comprises an end ring (20), the end ring (20) being connected to an end of the ring-shaped structure facing away from the end disc (10); the circumferential outer surface of the end ring (20) is flush with the outer surface of the blade (30) in the circumferential direction of the wind wheel; the end surfaces of the blades (30) and the end ring (20) are flush with each other in the axial direction of the wind wheel.

9. A centrifugal fan comprising a volute and the wind wheel of any of claims 1-8, the wind wheel being rotatably disposed within the volute.

10. A clothes drying apparatus comprising the centrifugal fan of claim 9, a clothes drying airflow path and a clothes treatment chamber which are in communication with each other, wherein the centrifugal fan is disposed on the clothes drying airflow path to generate a directional motion of air in the clothes drying airflow path.