Centrifugal fan impeller and volute-free centrifugal fan

Abstract

The utility model provides a centrifugal fan impeller and a volute-free centrifugal fan, the centrifugal fan impeller comprises a front disc, a rear disc and a plurality of blades, the blades are fixedly connected with the front disc and the rear disc and distributed around the axis at intervals, the blades are variable-section twisted backward blades, and the blades are provided with bent wing-shaped molded lines on the cross section of the centrifugal fan impeller; the wing-shaped molded lines of the blades are gradually close to the axis of the impeller of the centrifugal fan from the front disc to the rear disc and are gradually twisted around the axis; and from the front disc to the rear disc, the thickness of each blade and the chord length of the molded line of the wing type are gradually reduced. According to the centrifugal fan impeller provided by the invention, the blades are each flow surface variable cross-section wing type, the aerodynamic performance is good, the flow loss in the air channel between the two blades is small, the fan efficiency can be effectively improved, and the noise can be effectively reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of centrifugal fans, and specifically provides a centrifugal fan impeller and a volute-free centrifugal fan using the impeller. Background Art

[0002] The voluteless centrifugal fan has a simple structure, light weight, beautiful appearance, strong installation adaptability, and convenient maintenance. It is widely used in various fields. Since this type of product has only been around for a short time, its impeller is mainly in the form of a centrifugal impeller with a casing. In order to facilitate manufacturing and reduce production costs, the commonly used blades are flat blades or arc blades. In addition, in order to reduce noise, there are also products with equal-section airfoil blades.

[0003] In recent years, centrifugal fan impellers with twisted three-dimensional plate blades and twisted airfoil blades of equal cross-section have appeared. The above-mentioned centrifugal fan impellers achieve the effect of improving efficiency and reducing noise by improving the shape of the blades. However, for application fields that require a higher specific speed, such as a specific speed of more than 100, the above-mentioned existing centrifugal fan impellers are difficult to achieve the effect of high efficiency and low noise at the same time, so there is still much room for improvement. Utility Model Content

[0004] The purpose of the present application is to solve the problems existing in the above-mentioned prior art and to provide a centrifugal fan impeller with high efficiency and low noise and a volute-free centrifugal fan using the impeller.

[0005] A first aspect of the present application provides a centrifugal fan impeller, comprising a front disc, a rear disc, and a plurality of blades fixedly connected to the front disc and the rear disc and spaced apart around an axis;

[0006] The blade is a variable-section twisted backward blade having a curved airfoil-shaped profile line on the cross section of the centrifugal fan impeller;

[0007] The airfoil line of the blade gradually approaches the axis of the centrifugal fan impeller from the front disc to the rear disc, and gradually twists around the axis;

[0008] Furthermore, the thickness of the blade and the chord length of the airfoil profile line gradually decrease from the front disc to the rear disc.

[0009] Preferably, the inlet angle of the blade is in the range of 8° to 24°, the outlet angle is in the range of 15° to 45°, and the wrap angle is in the range of 40° to 75°.

[0010] Preferably, the ratio of the chord length of the longest airfoil profile line to the shortest airfoil profile line of the blade is 1.1-1.3.

[0011] Preferably, the ratio of the maximum thickness of the longest airfoil profile line to the shortest airfoil profile line of the blade is 1.5-4.

[0012] Preferably, the distance between the position where the maximum thickness of each airfoil profile line is located and the leading edge of the airfoil profile line is 1 / 5 to 1 / 2 of the chord length of the airfoil profile line.

[0013] Preferably, the front disk is composed of a straight line segment and at least two arc segments connected in sequence tangentially, the straight line segment is parallel to the axis, and the diffusion angle θ2 of the last arc segment of the front disk ranges from 0° to 45°; the outer diameter D2Q of the front disk is equal to the diameter D2 of the centrifugal fan impeller, and the ratio of the inner diameter D1 of the front disk to the outer diameter D2Q of the front disk is 0.7 to 0.8; the ratio of the height L4 of the front disk to the height L2 of the centrifugal fan impeller is 0.12 to 0.24.

[0014] Preferably, the rear disc is composed of a cone segment and at least two arc segments connected tangentially in sequence, and the inclination angle θ1 of the cone segment ranges from 0° to 30°; the diffusion angle θ3 of the last arc segment of the rear disc ranges from 0° to 45°; the ratio of the outer diameter D2H of the rear disc to the diameter D2 of the centrifugal fan impeller is 0.8 to 0.95; the ratio of the height L5 of the rear disc to the height L2 of the centrifugal fan impeller is 0.35 to 0.5.

[0015] Preferably, the ratio of the inlet diameter D1a of the blade at the front disk to the diameter D2 of the centrifugal fan impeller is 0.72-0.82, and the ratio of the inlet diameter D1b of the blade at the rear disk to the diameter D2 of the centrifugal fan impeller is 0.42-0.55; the ratio of the outlet diameter D2a of the blade at the front disk to the diameter D2 of the centrifugal fan impeller is 0.95-0.995, and the ratio of the outlet diameter D2b of the blade at the rear disk to the diameter D2 of the centrifugal fan impeller is 0.7-0.8; the ratio of the outlet width b2 of the centrifugal fan impeller to the height L2 is 0.8-0.9.

[0016] A second aspect of the present application provides a volute-less centrifugal fan, comprising a support portion, a motor, and the centrifugal fan impeller described above;

[0017] The body of the motor is fixedly connected to the support portion, and the rotor of the motor is coaxially fixedly connected to the rear disk of the centrifugal fan impeller.

[0018] Preferably, the volute-less centrifugal fan further comprises an air guide ring, which is fixedly connected to the support portion and has a distal end thereof axially extending into a front disk of the centrifugal fan impeller.

[0019] An embodiment of the present application provides a centrifugal fan impeller, whose blades have a three-dimensional shape with a variable cross-section, an inclination and a twist. The entire blade profile is diamond-shaped, and gradually inclines and twists toward the axis from the front disk to the rear disk. The centrifugal fan impeller with blades has a shape that fits the aerodynamic characteristics of the airflow in the air duct, can better adapt to the fan design parameters, and effectively reduce the aerodynamic losses in the air duct between the two blades. At the same time, its thickness gradually becomes thinner from the front disk to the rear disk, which can effectively improve the separation loss of the airflow at the front disk, thereby improving the fan efficiency and reducing the fan noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a centrifugal fan impeller provided according to an embodiment of the present application;

[0021] Figure 2 A schematic diagram of the structure of blades in a centrifugal fan impeller provided according to an embodiment of the present application;

[0022] Figure 3 A side view of a centrifugal fan impeller provided according to an embodiment of the present application;

[0023] Figure 4 It is a cross-sectional view taken along the AA direction of the centrifugal fan impeller provided according to an embodiment of the present application;

[0024] Figure 5 for Figure 4 A partial enlarged schematic diagram of

[0025] Figure 6 A BB-sectional view of a centrifugal fan impeller provided according to an embodiment of the present application;

[0026] Figure 7 for Figure 6 A partial enlarged schematic diagram of

[0027] Figure 8 An axial cross-sectional view of a centrifugal fan impeller provided according to an embodiment of the present application;

[0028] Fig. 9 It is a structural schematic diagram of a volute-free centrifugal fan provided according to an embodiment of the present application;

[0029] Fig.10 It is an exploded schematic diagram of a volute-free centrifugal fan provided according to an embodiment of the present application;

[0030] Fig.11 It is a front view of a volute-free centrifugal fan provided according to an embodiment of the present application;

[0031] Fig.12 A CC sectional view of a volute-free centrifugal fan provided according to an embodiment of the present application;

[0032] Fig.13 for Fig.12 Enlarged schematic diagram of the middle circle D.

[0033] Numbers in the figure

[0034] Centrifugal fan impeller 1, blade 11, leading edge 111, trailing edge 112, front disc side 113, rear disc side 114, front disc 12, rear disc 13, motor connector 131, motor 2, air guide ring 3, straight wall 31, first arc wall 321, second arc wall 322, third arc wall 323, support part 4, front side plate 41, rear side plate 42, connecting rod 43, axis 5. DETAILED DESCRIPTION

[0035] The present application is further described below based on preferred embodiments and with reference to the accompanying drawings. For ease of understanding, various components on the drawings are enlarged or reduced, but this practice is not intended to limit the protection scope of the present application.

[0036] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the products of the embodiments of the present application are usually placed when in use, it is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, in order to distinguish different units, the words first, second, etc. are used in this specification, but these are not limited by the order of manufacture, nor can they be understood as indicating or implying relative importance, and their names may be different in the detailed description and claims of the present application.

[0037] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

[0038] Figure 1 A schematic diagram of the three-dimensional structure of a centrifugal fan impeller 1 provided according to some embodiments of the present application is shown. Figure 1 As shown, the centrifugal fan impeller 1 includes a front disc 12, a rear disc 13, and a plurality of blades 11. The blades 11 are evenly spaced around the axis 5 of the centrifugal fan and are fixedly connected to the front disc 12 and the rear disc 13, respectively. Figure 1 In the illustrated embodiment, the number of blades 11 is five. In other embodiments, the number of blades 11 may be increased or decreased according to the design specifications of the wind turbine.

[0039] Figure 2 The structure of a blade 11 is further shown. Figure 1 and Figure 2 As shown, in an embodiment of the present application, the blade 11 used in the centrifugal fan impeller 1 is a variable-section twisted backward blade, which includes a leading edge 111 facing the direction of rotation of the centrifugal fan, a trailing edge 112 facing away from the direction of rotation of the centrifugal fan, a front disk side 113 connected to the front disk 12, and a rear disk side 114 connected to the rear disk 13.

[0040] Figure 3 is a side view of the centrifugal fan impeller 1. Figure 3 Cut along the AA line near the front disc 12 and the BB line near the rear disc 13 respectively. Figure 4 , Figure 5 The AA cross-sectional view and the partial enlarged schematic diagram of the upper right part are shown respectively. Figure 6 , Figure 7 The BB cross-sectional view and the partially enlarged schematic diagram of the upper right part are shown respectively.

[0041] like Figures 4 to 7 As shown, the blade 11 has a curved airfoil profile line on the cross section of the centrifugal fan impeller 1, so that a convex pressure surface and a concave suction surface are formed between the leading edge 111 and the trailing edge 112 of the blade 11. In some preferred embodiments, various airfoils with good performance known to those skilled in the art can be selected. For example, the thickness distribution law of the airfoil in patent CN216895034U can be used to symmetrically thicken both sides of the airfoil centerline to obtain a curved airfoil profile line.

[0042] Further, in the embodiments of the present application, Figures 4 to 7 As shown, the airfoil profile line of the blade 11 gradually approaches the axis 5 of the centrifugal fan impeller 1 from the front disk 12 to the rear disk 13, and gradually twists around the axis 5 (the twisting direction is the same as the impeller rotation direction), so that the blade 11 gradually forms a shape inclined and twisted toward the axis 5 from the front disk 12 to the rear disk 13.

[0043] Furthermore, if Figure 2 , Figures 4 to 7 As shown, the width of the airfoil profile line of the blade 11 gradually decreases from the front disc 12 to the rear disc 13, that is, the overall thickness of the blade 11 gradually becomes thinner from the front disc 12 to the rear disc 13. At the same time, the chord length of the airfoil profile line of the blade 11 gradually decreases from the front disc 12 to the rear disc 13, so that the overall length of the blade 11 gradually shortens from the front disc 12 to the rear disc 13. Obviously, Figure 2 The airfoil profile line on the front disk side of the middle blade 11 has the longest chord length, and the airfoil profile line on the rear disk side has the shortest chord length. In some preferred embodiments, the ratio of the chord length of the longest airfoil profile line to the shortest airfoil profile line of the blade 11 is 1.1-1.3.

[0044] Furthermore, the maximum thickness of the airfoil profile thickened on the front disc side is maxQ is the maximum thickness of the entire blade 11, and the maximum thickness of the airfoil profile thickened on the rear disc side δ maxH Less than δ maxQ In some preferred embodiments, δ maxH With δ maxQ In some other preferred embodiments, the distance between the maximum thickness position of each airfoil profile line and the leading edge of the airfoil profile line is 1 / 5 to 1 / 2 of the chord length of the airfoil profile line, that is, the maximum thickness of the blade 11 is located at a distance of 1 / 5 to 1 / 2 of the total length of the blade 11 from the leading edge.

[0045] From the front disk 12 to the rear disk 13, the maximum thickness of each section of the blade can be uniformly changed, for example, the δ of each section max The distribution can be 32mm, 30mm, 28mm, 26mm, 24mm, 22mm, 20mm, 18mm, 16mm, or other rules. The front disc is thick at 12 and the rear disc is thin at 13, with a natural transition from the front disc 12 to the rear disc 13 as the principle.

[0046] In addition, in some specific embodiments, the shape of the leading edge of the airfoil can be appropriately adjusted to make the profile of the blade 11 smooth, the leading edge thinned, and achieve a natural transition at the connection with the front disk 12 and the rear disk 13.

[0047] In some preferred embodiments, Figure 5 , Figure 7 As shown, the inlet angle of the blade 11 (for example, the angle β1 of the blade 11 near the front disk) Q and β1 near the rear disc H ) is in the range of 8° to 24°, and the outlet angle (for example, the β2 Q and β2 near the rear disc H ) is in the range of 15° to 45°, and the wrap angle (for example, the φ of the blade 11 near the front disk) Q and φ near the rear disc H ) ranges from 40° to 75°.

[0048] The above-mentioned blade 11 with a variable cross-section and twisted shape has a cross-sectional shape that adopts a wing airfoil, shaped like a goldfish, with a strong head and a thin tail, and the entire blade profile is in a diamond shape, gradually tilting and twisting toward the axis from the front disk 12 to the rear disk 13. The centrifugal fan impeller 1 using this type of variable cross-sectional and twisted blade 11 has a shape that fits the aerodynamic characteristics of the airflow in the air duct, can better adapt to the fan design parameters, and effectively reduce the aerodynamic loss of the air duct between the two blades. Its thickness gradually becomes thinner from the front disk 12 to the rear disk 13, which can effectively improve the separation loss of the airflow at the front disk 12, thereby improving the fan efficiency and reducing the fan noise.

[0049] Figure 8 1 shows a cross-sectional view of the centrifugal fan impeller 1 on an axial plane in some preferred embodiments (the figure shows the upper half of the centrifugal fan impeller 1).

[0050] like Figure 8 As shown, the front disk 12 is composed of a straight line segment and at least two arc segments connected tangentially in sequence, wherein the straight line segment is parallel to the axis 5, and the diffusion angle θ2 of the last arc segment ranges from 0° to 45°.

[0051] The outer diameter D2Q of the front disk 12 is equal to the diameter D2 of the centrifugal fan impeller 1, and the ratio of its inner diameter D1 to D2Q is 0.7-0.8; the ratio of the height L4 of the front disk 12 to the height L2 of the centrifugal fan impeller 1 is 0.12-0.24.

[0052] like Figure 8 As shown, the rear disc 13 is composed of a cone segment and at least two arc segments connected tangentially in sequence, wherein the inclination angle θ1 of the cone segment ranges from 0° to 30°, and the diffusion angle θ3 of the last arc segment ranges from 0° to 45°.

[0053] The ratio of the outer diameter D2H of the rear disc 13 to D2 is 0.8 to 0.95; the ratio of the height L5 of the rear disc 13 to L2 is 0.35 to 0.5.

[0054] like Figure 8 As shown, in some preferred embodiments, the ratio of the inlet diameter D1a of the blade 11 at the front disk 12 to D2 is 0.72-0.82, and the ratio of the inlet diameter D1b at the rear disk 13 to D2 is 0.42-0.55; the ratio of the outlet diameter D2a of the blade 11 at the front disk 12 to D2 is 0.95-0.995, and the ratio of the outlet diameter D2b at the rear disk 13 to D2 is 0.7-0.8; the ratio of the outlet width b2 of the centrifugal fan impeller 1 to L2 is 0.8-0.9.

[0055] The present application also provides a volute-free centrifugal fan using the centrifugal fan impeller 1 through an embodiment. Figures 9 to 12The structure diagram, exploded view, front view and CC-direction cross-sectional view of a centrifugal fan without a volute using the centrifugal fan impeller 1 are respectively shown. Fig.13 The portion of circle D in 12 is enlarged and displayed.

[0056] like Figures 9 to 12 As shown, the volute-less centrifugal fan includes a support portion 4, a motor 2, and the centrifugal fan impeller 1 mentioned above.

[0057] Specifically, the support portion 4 includes a front side plate 41, a rear side plate 42 and a plurality of connecting rods 43 for fixedly connecting the front side plate 41 and the rear side plate 42. The body of the motor 2 passes through the rear side plate 42 and is fixedly connected to the rear side plate 42. The rotor of the motor 2 is coaxially fixedly connected to the rear disk 13 of the centrifugal fan impeller 1 through the motor connecting piece 131.

[0058] In some preferred embodiments, a sealing ring is provided between the motor 2 and the rear disc 13 to prevent fine dust from entering the mounting cavity of the motor 2 and the centrifugal fan impeller 1 and to prevent unbalanced operation of the rotor caused by the fine dust.

[0059] In some preferred embodiments, Figures 9 to 12 As shown, the voluteless centrifugal fan also includes an air guide ring 3 arranged at the air inlet of the front disk 12, the air guide ring 3 is coaxially arranged with the centrifugal fan impeller 1, is fixedly connected to the front side plate 41 of the support portion 4 and penetrates the front side plate 41, and its end extends axially into the front disk 12 of the centrifugal fan impeller 1.

[0060] In some preferred embodiments, Fig.13 As shown, the air guide ring 3 is composed of a straight wall 31, a first arc wall 321, a second arc wall 322, and a third arc wall 323 which are connected tangentially in sequence, wherein the straight wall 31 is fixedly connected to the front side plate 41 as a flange of the air guide ring 3, the first arc wall 321, the second arc wall 322, and the third arc wall 323 are first contracted and then expanded along the axis 5, the end of the third arc wall 323 enters the front disk 12 with a lap depth a, and the gap with the inner wall of the front disk 12 is b. In some preferred embodiments, a ranges from 5 mm to 10 mm, and b ranges from 3 to 5 mm. In other preferred embodiments, the extension line of the third arc wall 323 toward the front disk 12 is tangent to the inner wall of the front disk 12.

[0061] By providing an air guide ring 3 that contracts first and then expands, the angle at which the airflow enters the impeller can be effectively corrected, the separation loss of the airflow at the front disk 12 can be improved, and the fan performance can be improved, the fan's high-efficiency working area can be widened, and the overall efficiency of the fan can be improved.

[0062] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A centrifugal fan impeller, comprising a front disc, a rear disc and a plurality of blades fixedly connected to the front disc and the rear disc and spaced apart around an axis, characterized in that: The blade is a variable-section twisted backward blade having a curved airfoil-shaped profile line on the cross section of the centrifugal fan impeller; The airfoil line of the blade gradually approaches the axis of the centrifugal fan impeller from the front disc to the rear disc, and gradually twists around the axis; Furthermore, the thickness of the blade and the chord length of the airfoil profile line gradually decrease from the front disc to the rear disc.

2. The centrifugal fan impeller according to claim 1, characterized in that: The inlet angle of the blade is in the range of 8° to 24°, the outlet angle is in the range of 15° to 45°, and the wrap angle is in the range of 40° to 75°.

3. The centrifugal fan impeller according to claim 1, characterized in that: The ratio of the chord length of the longest airfoil profile line to the shortest airfoil profile line of the blade is 1.1 to 1.

3.

4. The centrifugal fan impeller according to claim 1, characterized in that: The ratio of the maximum thickness of the longest airfoil profile line to the shortest airfoil profile line of the blade is 1.5-4.

5. The centrifugal fan impeller according to claim 4, characterized in that: The distance between the position where the maximum thickness of each airfoil profile line is located and the leading edge of the airfoil profile line is 1 / 5 to 1 / 2 of the chord length of the airfoil profile line.

6. The centrifugal fan impeller according to claim 1, characterized in that: The front disk is composed of a straight line segment and at least two arc segments connected tangentially in sequence, the straight line segment is parallel to the axis, and the diffusion angle θ2 of the last arc segment of the front disk is in the range of 0° to 45°; The outer diameter D2Q of the front disk is equal to the diameter D2 of the centrifugal fan impeller, and the ratio of the inner diameter D1 of the front disk to the outer diameter D2Q of the front disk is 0.7 to 0.8; The ratio of the height L4 of the front disk to the height L2 of the centrifugal fan impeller is 0.12 to 0.

24.

7. The centrifugal fan impeller according to claim 1, characterized in that: The rear disc is composed of a cone segment and at least two arc segments connected tangentially in sequence, the inclination angle θ1 of the cone segment ranges from 0° to 30°; the diffusion angle θ3 of the last arc segment of the rear disc ranges from 0° to 45°; The ratio of the outer diameter D2H of the rear disc to the diameter D2 of the centrifugal fan impeller is 0.8 to 0.95; The ratio of the height L5 of the rear disc to the height L2 of the centrifugal fan impeller is 0.35-0.

5.

8. The centrifugal fan impeller according to claim 1, characterized in that: The ratio of the inlet diameter D1a of the blade at the front disc to the diameter D2 of the centrifugal fan impeller is 0.72 to 0.82, and the ratio of the inlet diameter D1b of the blade at the rear disc to the diameter D2 of the centrifugal fan impeller is 0.42 to 0.55; The ratio of the outlet diameter D2a of the blade at the front disc to the diameter D2 of the centrifugal fan impeller is 0.95 to 0.995, and the ratio of the outlet diameter D2b of the blade at the rear disc to the diameter D2 of the centrifugal fan impeller is 0.7 to 0.8; The ratio of the outlet width b2 to the height L2 of the centrifugal fan impeller is 0.8-0.

9.

9. A centrifugal fan without volute, characterized in that: It comprises a support part, a motor, and the centrifugal fan impeller according to claim 1; The body of the motor is fixedly connected to the support portion, and the rotor of the motor is coaxially fixedly connected to the rear disk of the centrifugal fan impeller.

10. The volute-less centrifugal fan according to claim 9, characterized in that: It also includes an air guide ring, which is fixedly connected to the support portion and has a distal end that axially extends into the front disk of the centrifugal fan impeller.

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