Blade, centrifugal wind wheel, centrifugal fan and design method of blade

Abstract

The invention relates to the technical field of ventilation equipment, and discloses a blade, a centrifugal wind wheel, a centrifugal fan and a blade design method.The blade is applied to the centrifugal wind wheel, the centrifugal wind wheel is provided with a center shaft, the blade is provided with an inlet edge and an outlet edge, the inlet edge is close to the center shaft, and the outlet edge is away from the center shaft; wherein the inlet edge comprises a first curve section and a second curve section which are in smooth transition connection, the first curve section is in a concave curve shape, and the second curve section is in a convex curve shape; the outlet edge comprises a third curve section which is in a concave curve shape. According to the blade, the centrifugal wind wheel, the centrifugal fan and the design method of the blade, the efficiency bottleneck of an existing centrifugal wind wheel can be broken through, and the efficiency of the centrifugal wind wheel is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ventilation equipment, and in particular to a blade, a centrifugal wind wheel, a centrifugal fan and a design method of the blade. Background Art

[0002] With the vigorous promotion of modernization construction, centrifugal wind wheels have a wide range of applications. In order to fulfill the social responsibility of energy conservation and emission reduction, various application fields pay more and more attention to the efficiency improvement of centrifugal wind wheels. Among them, the blades are the key components of the centrifugal wind wheel, which directly affect the efficiency of the centrifugal wind wheel.

[0003] However, in the related art, affected by the structure of the blades, during the process of the airflow flowing to the inlet edge of the blades and flowing out from the outlet edge, the kinetic energy of the airflow is dissipated in the form of internal energy, sound pressure, etc. due to the constraints of the blades. This also makes it difficult to further improve the efficiency of the centrifugal wind wheel in the related art. Summary of the invention

[0004] In view of this, the present invention provides a blade, a centrifugal wind wheel, a centrifugal fan and a design method for a blade to solve the problem in the related art that the efficiency of the centrifugal wind wheel is difficult to be further improved.

[0005] In a first aspect, the present invention provides a blade for a centrifugal wind wheel, wherein the centrifugal wind wheel has a central axis, and the blade has an inlet edge and an outlet edge, wherein the inlet edge is close to the central axis, and the outlet edge is far away from the central axis; wherein the inlet edge includes a first curve segment and a second curve segment connected by a smooth transition, wherein the first curve segment is an inward-concave curve, and the second curve segment is an outward-convex curve; and the outlet edge includes a third curve segment, wherein the third curve segment is an inward-concave curve.

[0006] In an optional embodiment, the blade has a blade top and a blade root, the end of the first curve segment away from the second curve segment is connected to the blade top, the end of the second curve segment away from the first curve segment is connected to the blade root, and the connection point P of the first curve segment and the second curve segment is located between 1 / 2L and 3 / 4L of the blade; wherein L is the extension length of the blade from the blade root to the blade top, which is defined as 0 at the blade root and L at the blade top.

[0007] In an optional embodiment, the projection of the central axis on the rotating surface of the blade is the axis O; the connection point between the second curve segment and the blade root is E, and the projection point of the connection point E on the rotating surface of the blade is E1; wherein, point E1 and the axis O together form a reference line OE1, and the projections of the first curve segment and the second curve segment on the rotating surface of the blade are respectively located on both sides of the reference line OE1.

[0008] In an optional embodiment, the connection point between the first curve segment and the blade top is A, and the projection point of the connection point A on the rotating surface of the blade is A1; at 3 / 4L of the blade, the projection of the first curve segment on the rotating surface of the blade is B1; at 1 / 2L of the blade, the projection of the second curve segment on the rotating surface of the blade is C1; at 1 / 4L of the blade, the projection of the second curve segment on the rotating surface of the blade is D1; ​​wherein, the angle between the projection point A1 and the point E1 with the axis O as the angle is δa, the angle between the projection point B1 and the point E1 with the axis O as the angle is δb, the angle between the projection point C1 and the point E1 with the axis O as the angle is δc, and the angle between the projection point D1 and the point E1 with the axis O as the angle is δd; the ratio relationship of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:6.

[0009] In an optional embodiment, at the blade top, the blade angle is θa; at 3 / 4L of the blade, the blade angle is θb; at 1 / 2L of the blade, the blade angle is θc; at 1 / 4L of the blade, the blade angle is θd; at the blade root, the blade angle is θe; wherein the ratio range of θa, θb, θc, θd, and θe is θa:θb:θc:θd:θe=1:(1-1.1):1.2:(1.2-1.3):(1.2-1.3).

[0010] In an optional implementation, the value range of θa is 60°-100°.

[0011] In a second aspect, the present invention also provides a blade design method for obtaining a blade as described above, comprising the steps of: S1: defining an inlet edge, an outlet edge, a blade root and a blade top of a basic blade, and obtaining at least five blade centerlines of the basic blade, wherein at least five blade centerlines are equally spaced from the blade top to the blade root; S2: obtaining a projection of the basic blade on a rotating surface, and defining starting points and end points of at least five blade centerlines in the projection of the basic blade; wherein the starting point of the blade centerline is the end point of the blade centerline at the inlet edge, and the end point of the blade centerline is the end point of the blade centerline at the outlet edge; S3: taking the starting point E1 of the blade centerline at the blade root as a reference point and the axis O as a vertex, determining the ratio relationship between the starting point of each blade centerline and the angle between E1 and the axis O, so that the inlet edge presents an "S" shape; S4: determining the ratio relationship of the wrap angles of each blade centerline, so that the outlet edge presents a "C" shape; S5: determining the wrap angle value of any blade centerline, and determining the wrap angle values ​​of other blade centerlines according to the ratio relationship of the wrap angles of each blade centerline, thereby determining the shape of the blade.

[0012] In an optional embodiment, in step S1, at least five blade center lines are obtained, including at least blade center line a located at the blade top, blade center line b located at 3 / 4L of the base blade, blade center line c located at 1 / 2L of the base blade, blade center line d located at 1 / 4L of the base blade, and blade center line e located at the blade root; wherein L is the extension length of the base blade from the blade root to the blade top, which is defined as 0 at the blade root and L at the blade top; in step S3, the angle between the starting point A1 of the blade center line a and point E1 with the axis O as the angle is recorded as δa, the angle between the starting point B1 of the blade center line b and point E1 with the axis O as the angle is recorded as δb, and the angle between the starting point B1 of the blade center line c and point E1 with the axis O as the angle is recorded as δc. The angle between point C1 and point E1 with the axis O as the angle is recorded as δc, and the angle between the starting point D1 of the center line of blade d and point E1 with the axis O as the angle is recorded as δd; the ratio relationship of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:6; in step S4, the wrap angle of the center line of blade a is θa, the wrap angle of the center line of blade b is θb, the wrap angle of the center line of blade c is θc, the wrap angle of the center line of blade d is θd, and the wrap angle of the center line of blade e is θe; wherein, the ratio range of θa, θb, θc, θd, and θe is θa:θb:θc:θd:θe=1:(1-1.1):1.2:(1.2-1.3):(1.2-1.3).

[0013] In a third aspect, the present invention further provides a centrifugal wind wheel, comprising: a blade as described above; or a blade obtained by using the blade design method as described above.

[0014] In a fourth aspect, the present invention further provides a centrifugal fan, comprising: a blade as described above; or a blade obtained by using the blade design method as described above; or a centrifugal wind wheel as described above.

[0015] In the technical solution of the present invention, the inlet edge of the blade includes a first curve segment and a second curve segment that are smoothly connected, the first curve segment is a concave curve segment, and the second curve segment is a convex curve segment, so that the inlet edge of the blade is in an "S" shape; the outlet edge of the blade includes a third curve segment, and the third curve segment is a concave curve segment, so that the outlet edge of the blade is in a "C" shape. By utilizing the blades of the present invention, the inlet edge of the blade is in an "S" shape, and presents a phase difference distribution in the circumferential direction of the centrifugal wind wheel. The outlet edge is in a "C" shape, and also presents a phase difference distribution in the circumferential direction of the centrifugal wind wheel. The phase difference of the inlet edge changes the air flow characteristics at the inlet of the blade, forms a phase difference in the airflow angle of attack, and suppresses negative effects such as pressure difference loss, impact loss, eddy current, and noise; and synergistically optimizes the phase state of the flow in the blade channel, changes local pressure accumulation and kinetic energy mixing, and then optimizes the entire power transfer process and improves the efficiency of the centrifugal impeller; at the same time, the phase difference of the inlet edge and the phase difference of the blade outlet together in space, widen the spatial distance between the high and low kinetic energy outlet airflows, and thereby suppresses the mixing of the flow field at the blade outlet, thereby reducing the dissipation of kinetic energy during the mixing process and further improving the efficiency of the centrifugal wind wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a schematic structural diagram of a centrifugal wind wheel according to an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the structure of a blade according to an embodiment of the present invention;

[0019] Figure 3 This is a structural schematic diagram of step S1 in a blade design method according to an embodiment of the present invention;

[0020] Figure 4 Schematic diagram of the structure of step S2 in a blade design method according to an embodiment of the present invention;

[0021] Figure 5 This is a structural schematic diagram of step S3 in a blade design method according to an embodiment of the present invention;

[0022] Figure 6 Schematic diagram of the structure of step S4 in a blade design method according to an embodiment of the present invention.

[0023] Description of reference numerals:

[0024] 10. Centrifugal wind wheel; 1. Blade; 11. Inlet edge; 111. First curved segment; 112. Second curved segment; 12. Outlet edge; 121. Third curved segment; 13. Blade top; 14. Blade root; 15. a blade centerline; 16. b blade centerline; 17. c blade centerline; 18. d blade centerline; 19. e blade centerline;

[0025] 2. Wheel cover; 3. Wheel disc;

[0026] Z, center axis. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0028] Combine the following Figures 1 to 6 , describing an embodiment of the present invention.

[0029] According to an embodiment of the present invention, on the one hand, a blade 1 applied to a centrifugal wind wheel 10 is provided. Figure 1 As shown, the centrifugal wind wheel 10 has a central axis Z, and the blade 1 has an inlet edge 11 and an outlet edge 12, wherein the inlet edge 11 is close to the central axis Z, and the outlet edge 12 is far from the central axis Z. The inlet edge 11 includes a first curved segment 111 and a second curved segment 112 connected by a smooth transition, wherein the first curved segment 111 is an inwardly concave curved segment, and the second curved segment 112 is an outwardly convex curved segment, so that the inlet edge 11 of the blade 1 is shaped like an "S". The outlet edge 12 includes a third curved segment 121, and the third curved segment 121 is an inwardly concave curved segment, so that the outlet edge 12 of the blade 1 is shaped like a "C".

[0030] It can be understood that the centrifugal wind wheel 10 includes a plurality of blades 1 arranged around the central axis Z and spaced apart along the circumferential direction of the centrifugal wind wheel 10, and a blade channel is formed between two connected blades 1 for airflow to pass through. The central axis Z is the rotation axis of the blade 1, the inlet edge 11 of the blade 1 is the inlet of the blade channel, and the outlet edge 12 is the outlet of the blade 1.

[0031] By utilizing the blade 1 of the present invention, the inlet edge 11 of the blade 1 is in an "S" shape and presents a phase difference distribution in the circumferential direction of the centrifugal wind wheel 10, and the outlet edge 12 is in a "C" shape and also presents a phase difference distribution in the circumferential direction of the centrifugal wind wheel 10. The phase difference of the inlet edge 11 changes the air flow characteristics at the inlet of the blade 1, forming a phase difference in the airflow angle of attack, suppressing negative effects such as pressure difference loss, impact loss, eddy current, and noise; and synergistically optimizes the phase state of the flow in the blade channel, changes local pressure accumulation and kinetic energy mixing, and then optimizes the entire power transfer process and improves the efficiency of the centrifugal impeller; at the same time, the phase difference of the inlet edge 11 and the phase difference of the outlet of the blade 1 together in space, widen the spatial distance between the high and low kinetic energy outlet airflows, and thereby suppresses the mixing of the flow field at the outlet of the blade 1, thereby reducing the dissipation of kinetic energy during the mixing process and further improving the efficiency of the centrifugal wind wheel 10.

[0032] In the prior art, limited by the structure of the blade 1, the upper limit of the single wind wheel efficiency of the centrifugal wind wheel 10 is usually about 75%. However, it has been verified in practice that by using the blade 1 of the present invention, the upper limit of the single wind wheel efficiency of the centrifugal wind wheel 10 can be increased to 78%, which greatly improves the efficiency of the centrifugal wind wheel 10.

[0033] More specifically, in some embodiments, Figure 2 As shown, the blade 1 has a blade tip 13 and a blade root 14, the end of the first curved segment 111 away from the second curved segment 112 is connected to the blade tip 13, the end of the second curved segment 112 away from the first curved segment 111 is connected to the blade root 14, and the connection point P of the first curved segment 111 and the second curved segment 112 is located between 1 / 2L and 3 / 4L of the blade 1. Wherein, L is the extension length of the blade 1 from the blade root 14 to the blade tip 13, for the convenience of description, the blade root 14 is defined as 0, and the blade tip 13 is defined as L. With such arrangement, the first curved segment 111 near the blade top 13 is in the shape of a concave curve, and the second curved segment 112 near the blade root 14 is in the shape of a convex curve. The airflow near the blade root 14 can enter the blade 1 first and do work first, and the airflow near the blade top 13 enters the blade 1 later and does work later, thereby forming a work time difference between the upper and lower parts of the blade 1, so that the airflow forms an airflow attack angle phase difference according to the ideal effect, optimizes the phase state of the flow in the blade channel, and suppresses mixing of the flow field at the outlet of the blade 1.

[0034] It can be understood that the blade 1 usually has a certain thickness, so the first curved segment 111, the second curved segment 112 and the third curved segment 121 can all be understood as curved surfaces. The connection point P of the first curved segment 111 and the second curved segment 112 can be any point at the connection of the first curved segment 111 and the second curved segment 112 in the thickness direction of the blade 1. Exemplarily, the connection point P can be the intersection of the connection of the first curved segment 111 and the second curved segment 112 and the center line of the blade at this position.

[0035] In some embodiments, Figure 5 As shown, the projection of the central axis Z on the rotation surface of the blade 1 is the axis O. The rotation surface refers to any plane with the rotation axis of the blade 1, that is, the central axis Z, as the normal. Figure 4 As shown, direction X, direction Y and central axis Z are perpendicular to each other, the rotation plane is any plane on the XY plane formed by direction X and direction Y, and the axis O is the projection of the central axis Z on the XY plane.

[0036] Furthermore, the connection point between the second curved segment 112 and the blade root 14 is E, and the projection point of the connection point E on the rotation surface of the blade 1 is E1. Specifically, the connection point E and the projection point E1 can be understood as the intersection of the blade center line at the blade root 14 and the end of the second curved segment 112 away from the first curved segment 111.

[0037] Among them, the projection point E1 and the axis O together form a reference line OE1, and the projections of the first curve segment 111 and the second curve segment 112 on the rotating surface of the blade 1 are respectively located on both sides of the reference line OE1, that is, the projection of the connection point P of the first curve segment 111 and the second curve segment 112 on the rotating surface can be located on the extension line of the reference line OE1.

[0038] Corresponding to the three-dimensional structure of the blade 1, in the extension direction of the blade 1, specifically, the radial extension direction of the blade 1 in the centrifugal wind wheel 10, that is, Figure 2 In the left-right direction, the first curved segment 111 protrudes from the blade tip 13 and is recessed in the blade root 14 , and the second curved segment 112 protrudes from the blade tip 13 and the blade root 14 .

[0039] More specifically, in some embodiments, the connection point between the first curved segment 111 and the blade top 13 is A, and the projection point of the connection point A on the rotating surface of the blade 1 is A1; at 3 / 4L of the blade 1, the projection of the first curved segment 111 on the rotating surface of the blade 1 is B1; at 1 / 2L of the blade 1, the projection of the second curved segment 112 on the rotating surface of the blade 1 is C1; at 1 / 4L of the blade 1, the projection of the second curved segment 112 on the rotating surface of the blade 1 is D1.

[0040] It can be understood that the above-mentioned connection point A, projection points A1, B1, C1, D1 can all be understood as the intersection points of the blade centerline and the inlet edge 11 at corresponding positions.

[0041] Among them, the angle between the projection point A1 and the projection point E1 with the axis O as the angle is recorded as δa, the angle between the projection point B1 and the projection point E1 with the axis O as the angle is recorded as δb, the angle between the projection point C1 and the projection point E1 with the axis O as the angle is recorded as δc, and the angle between the projection point D1 and the projection point E1 with the axis O as the angle is recorded as δd; the ratio relationship of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:6. Under this ratio relationship, the phase difference distribution relationship at the inlet edge 11 of the blade 1 can be accurately controlled, and then the phase difference of the airflow angle of attack at the inlet edge 11 can be accurately controlled, so as to achieve a better effect of suppressing negative effects such as pressure difference loss, impact loss, vortex, noise, etc., and ensure the reliability of improving efficiency. At the same time, since a phase difference is formed at the inlet edge 11 according to the ratio relationship, the flow in the blade channel will inevitably form a corresponding phase difference relationship. The airflow in the blade channel is affected by the phase difference to achieve optimization of the phase state, thereby optimizing the entire work process and improving the efficiency of the centrifugal wind wheel 10.

[0042] In some embodiments, at the tip 13, the wrap angle of the blade 1 is θa; at 3 / 4L of the blade 1, the wrap angle of the blade 1 is θb; at 1 / 2L of the blade 1, the wrap angle of the blade 1 is θc; at 1 / 4L of the blade 1, the wrap angle of the blade 1 is θd; at the root 14, the wrap angle of the blade 1 is θe; wherein, the ratio range of θa, θb, θc, θd, θe is θa:θb:θc:θd:θe=1:(1-1.1):1.2:(1.2-1.3):(1.2-1.3). Since the work capacity of the blade centerline at different parts of the blade 1 is different, the kinetic energy of the airflow flowing out at the blade outlet is different, and the difference is large, so that the flow field is mixed at the outlet, which consumes a large amount of kinetic energy. By controlling the ratio of the above-mentioned wrap angle within this range, it is possible to achieve a better effect of suppressing the mixing of the flow field at the outlet, thereby reducing the consumption of kinetic energy and maximizing the efficiency of the centrifugal impeller 10.

[0043] Exemplarily, θa:θb:θc:θd:θe=1:1:1.2:1.2:1.2.

[0044] Exemplarily, θa:θb:θc:θd:θe=1:1.01:1.2:1.21:1.22.

[0045] Exemplarily, θa:θb:θc:θd:θe=1:1.05:1.2:1.24:1.24.

[0046] Exemplarily, θa:θb:θc:θd:θe=1:1.1:1.2:1.3:1.3.

[0047] Specifically, Figure 6As shown, at the blade tip 13, the projection point of the third curve segment 121 on the rotation surface is A2; at 3 / 4L of the blade 1, the projection point of the third curve segment 121 on the rotation surface of the blade 1 is B2; at 1 / 2L of the blade 1, the projection point of the third curve segment 121 on the rotation surface of the blade 1 is C2; at 1 / 4L of the blade 1, the projection point of the third curve segment 121 on the rotation surface of the blade 1 is D2; at the blade root 14, the projection point of the third curve segment 121 on the rotation surface is E2. Among them, the angle between A1 and A2 about the axis O is the wrap angle θa, the angle between B1 and B2 about the axis O is the wrap angle θb, the angle between C1 and C2 about the axis O is the wrap angle θc, the angle between D1 and D2 about the axis O is the wrap angle θd, and the angle between E1 and E2 about the axis O is the wrap angle θe.

[0048] It can be understood that the above-mentioned projection points A2, B2, C2, D2, and E2 can all be understood as the intersection points of the blade center line and the outlet edge 12 at the corresponding positions.

[0049] Furthermore, in some embodiments, the value range of θa is 60°-100°, and the wrap angle values ​​of θb, θc, θd, and θe can be determined based on the ratio relationship of the above-mentioned wrap angles, so as to achieve the purpose of coordinated cooperation between the phase difference at the inlet edge 11 and the phase difference at the outlet edge 12, thereby suppressing mixing of the flow field at the outlet edge 12.

[0050] According to an embodiment of the present invention, on the other hand, a method for designing a blade 1 is provided, for obtaining the blade 1 as described above, and specifically comprises the steps of:

[0051] S1: defining an inlet edge 11, an outlet edge 12, a blade root 14 and a blade tip 13 of a basic blade, and obtaining at least five blade center lines of the basic blade, wherein at least five blade center lines are evenly spaced from the blade tip 13 to the blade root 14;

[0052] S2: Obtain the projection of the basic blade on the rotating surface, and define the starting points and end points of at least five blade midlines in the projection of the basic blade; wherein the starting point of the blade midline is the end point of the blade midline at the inlet edge 11, and the end point of the blade midline is the end point of the blade midline at the outlet edge 12;

[0053] S3: Taking the starting point E1 of the blade centerline at the blade root 14 as the reference point and the axis O as the vertex, determine the ratio between the starting point of each blade centerline and the angle between E1 and the axis O, so that the inlet edge 11 presents an "S" shape;

[0054] S4: Determine the ratio of the wrap angles of the midlines of the blades so that the outlet edge 12 is in a "C" shape;

[0055] S5: Determine the wrap angle value of any blade midline, and determine the wrap angle values ​​of other blade midlines according to the ratio relationship of the wrap angles of the blade midlines, thereby determining the shape of blade 1.

[0056] The blade 1 obtained by the blade 1 design method of the present invention can effectively improve the efficiency of the centrifugal wind wheel 10, and the method uses the ratio relationship between the starting point of each blade centerline and the angle E1 with the axis O as the angle, and the ratio relationship between the wrap angles of each blade centerline to limit the phase difference at the inlet edge 11 and the outlet edge 12. The shape of the blade 1 is not affected by the size of the blade 1 or the centrifugal wind wheel 10 to which it is applied. Therefore, regardless of the actual size of the blade 1 or the centrifugal wind wheel 10 to which it is applied, the efficiency of the centrifugal wind wheel 10 can be effectively improved under similar specific speed conditions, and the applicability is good.

[0057] More specifically, in some embodiments, in step S1, at least five blade center lines are obtained, including at least a blade center line 15 located at the blade tip 13, b blade center line 16 located at 3 / 4L of the base blade, c blade center line 17 located at 1 / 2L of the base blade, d blade center line 18 located at 1 / 4L of the base blade, and e blade center line 19 located at the blade root 14. Wherein, L is the extension length of the base blade from the blade root 14 to the blade tip 13, which is defined as 0 at the blade root 14 and L at the blade tip 13; it can be understood that in the entire design process, the position of the blade root 14 and the blade tip 13 of the base blade and the blade surface shape do not change, and the L of the base blade is also the L of the blade 1 finally obtained.

[0058] In some embodiments, in step S3, the angle between the starting point A1 of the blade centerline 15 and the reference point E1 with the axis O as the angle is recorded as δa, the angle between the starting point B1 of the blade centerline 16 and the reference point E1 with the axis O as the angle is recorded as δb, the angle between the starting point C1 of the blade centerline 17 and the reference point E1 with the axis O as the angle is recorded as δc, and the angle between the starting point D1 of the blade centerline 18 and the reference point E1 with the axis O as the angle is recorded as δd; the ratio relationship of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:6. Under the limitation of this ratio relationship, the phase difference distribution at the inlet edge 11 of the blade 1 can be accurately controlled, and then the phase difference of the airflow attack angle at the inlet edge 11 can be accurately controlled, so as to achieve a better effect of suppressing negative effects such as pressure difference loss, impact loss, vortex, noise, etc., and ensure the reliability of improving efficiency. At the same time, since a phase difference is formed at the inlet edge 11 according to the ratio relationship, the flow in the blade channel will inevitably form a corresponding phase difference relationship. The airflow in the blade channel is affected by the phase difference to achieve optimization of the phase state, thereby optimizing the entire work process and improving the efficiency of the centrifugal wind wheel 10.

[0059] In some embodiments, in step S4, the wrap angle of the center line 15 of blade a is θa, the wrap angle of the center line 16 of blade b is θb, the wrap angle of the center line 17 of blade c is θc, the wrap angle of the center line 18 of blade d is θd, and the wrap angle of the center line 19 of blade e is θe; wherein, the ratio range of θa, θb, θc, θd, θe is θa:θb:θc:θd:θe=1:(1-1.1):1.2:(1.2-1.3):(1.2-1.3). Controlling the ratio of the above wrap angles within this range can achieve a better effect of suppressing the mixing of the flow field at the outlet, thereby reducing the consumption of kinetic energy and maximizing the efficiency of the centrifugal wind wheel 10.

[0060] The design method of the present invention is described below with a specific embodiment:

[0061] S1: Figure 3 As shown, the four sides of the basic blade are defined, namely the inlet side 11, the outlet side 12, the blade root 14 and the blade top 13. From the blade top 13 to the blade root 14, five blade center lines are defined that divide the basic blade into four equal parts, which are:

[0062] a blade midline 15 (leaf top 13);

[0063] b blade centerline 16 (3 / 4L);

[0064] c blade centerline 17 (2 / 4L);

[0065] d blade centerline 18 (1 / 4L);

[0066] e Blade center line 19 (blade root 14).

[0067] In this step, the center line of each blade can be obtained by three-dimensional design theory and CFD iteration.

[0068] It is understandable that the blade 1 also has a suction surface and a pressure surface, and the present invention does not specifically limit the shape of the blade surface of the blade 1, as long as it meets the actual application requirements. Generally, the suction surface and the pressure surface are both curved surface structures twisted in three-dimensional space.

[0069] S2: Obtain the projection of the basic blade on the rotating surface, and define the starting points and end points of 5 blade midlines in the projection of the basic blade, which are:

[0070] a. The starting point of the blade centerline 15 is point A1 on the inlet edge 11, and the end point is point A2 on the outlet edge 12;

[0071] b The starting point of the blade centerline 16 is point B1 on the inlet edge 11, and the end point is point B2 on the outlet edge 12;

[0072] c. The starting point of the blade centerline 17 is C1 on the inlet edge 11, and the end point is C2 on the outlet edge 12;

[0073] d The starting point of the blade centerline 18 is point D1 on the inlet edge 11, and the end point is point D2 on the outlet edge 12;

[0074] The starting point of the blade center line 19 is point E1 on the inlet edge 11, and the end point is point E2 on the outlet edge 12.

[0075] S3: Determine the phase relationship of the starting points of the 5 blade midlines:

[0076] Take point E1 as the phase reference;

[0077] The angle between points A1 and E1 with axis O as the angle is denoted as δa;

[0078] The angle between point B1 and E1 with axis O as the angle is denoted as δb;

[0079] The angle between point C1 and E1 with axis O as the angle is denoted as δc;

[0080] The angle between points D1 and E1 with axis O as the angle is denoted as δd;

[0081] Taking the inlet direction of blade 1 as positive and the outlet direction as negative, the phase relationship between the starting points of each midline is:

[0082] δa:δb:δc:δd=-12:-5:5:6.

[0083] After this step, the starting points of the center lines of the blades are connected to form the first curved segment 111 and the second curved segment 112 , that is, the inlet edge 11 of the blade 1 presents an “S” shape.

[0084] S4: Determine the ratio of the wrap angles of the midlines of the blades:

[0085] The angle between A1 and A2 about the axis O is defined as the wrap angle of the center line 15 of the blade a, denoted as θa;

[0086] The angle between B1 and B2 about the axis O is defined as the wrap angle of the center line 16 of the blade b, denoted as θb;

[0087] The angle between C1 and C2 about the axis O is defined as the wrap angle of the c blade centerline 17, denoted as θc;

[0088] The angle between D1 and D2 about the axis O is defined as the wrap angle of the blade centerline 18, denoted as θd;

[0089] The angle between E1 and E2 about the axis O is defined as the wrap angle of the e-blade centerline 19, denoted as θe;

[0090] θa:θb:θc:θd:θe=1:1.05:1.2:1.24:1.24.

[0091] After this step, the endpoints of the midlines of the blades are connected to form the third curved segment 121, that is, the outlet edge 12 of the blade 1 is in a "C" shape, and there is no need to constrain the phase relationship between the endpoints of the midlines of the blades.

[0092] S5: Determine the wrap angle value of any blade midline, and determine the wrap angle values ​​of other blade midlines according to the ratio relationship of the wrap angles of the blade midlines, thereby determining the shape of blade 1.

[0093] After the above steps S3 and S4, the shape of blade 1 needs to determine a wrap angle value of a center line (optional one) to uniquely determine the angle ratio relationship. At this time, no matter how the size of the impeller changes, the proportional relationship of blade 1 relative to the impeller will no longer change. The wrap angle value of blade 1 is related to the specific speed. Preferably, the specific speed range of the applied centrifugal impeller 10 is 15-5, and the corresponding value range of θa is 60°-100°.

[0094] It can be understood that the design method of the present invention only limits the angle relationship, and does not limit the size of the blade 1. Therefore, the design method of the present invention can be used for the design and application of the blade 1 of the centrifugal wind wheel 10 with a specific speed or a similar specific speed. That is, no matter the actual size of the blade 1 or the centrifugal wind wheel 10 to which it is applied, it is within the scope of the present invention.

[0095] According to an embodiment of the present invention, in another aspect, a centrifugal wind wheel 10 is provided, comprising: a blade 1 as described in any of the above embodiments; or a blade 1 obtained by using a design method for a blade 1 as described in any of the above embodiments.

[0096] Specifically, Figure 1 As shown, the centrifugal wind wheel 10 includes a wheel cover 2, a wheel disc 3 and a plurality of blades 1, wherein the blade tip 13 of the blade 1 is connected to the wheel cover 2, and the blade root 14 of the blade 1 is connected to the wheel disc 3. The wheel cover 2 and the wheel disc 3 are both annular and coaxially arranged, and both have a common central axis Z, which is the rotation axis of the centrifugal wind wheel 10. The plurality of blades 1 are arranged at intervals around the central axis Z, that is, arranged at intervals around the circumference of the wheel cover 2 and / or the wheel disc 3.

[0097] Each blade 1 has an inlet edge 11 and an outlet edge 12, wherein the inlet edge 11 is close to the central axis Z and the outlet edge 12 is far from the central axis Z. The inlet edge 11 includes a first curved segment 111 and a second curved segment 112 which are smoothly connected, wherein the first curved segment 111 is an inwardly concave curved segment and the second curved segment 112 is an outwardly convex curved segment, so that the inlet edge 11 of the blade 1 is shaped like an "S". The outlet edge 12 includes a third curved segment 121, which is an inwardly concave curved segment, so that the outlet edge 12 of the blade 1 is shaped like a "C".

[0098] According to an embodiment of the present invention, on the other hand, a centrifugal fan is provided, comprising: a blade 1 as described in any of the above embodiments; or a blade 1 obtained by using the design method of the blade 1 as described in any of the above embodiments; or a centrifugal wind wheel 10 as described above.

[0099] Since the centrifugal wind wheel 10 and the centrifugal fan of the present invention both include the blade 1 of the present invention or the blade 1 obtained by the design method of the blade 1 of the present invention, the centrifugal wind wheel 10 and the centrifugal fan of the present invention have the same technical effects as the blade 1 of the present invention or the design method of the blade 1 of the present invention, and will not be repeated here.

[0100] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A blade, applied to a centrifugal wind wheel (10), the centrifugal wind wheel (10) having a central axis (Z), characterized in that: The blade (1) has an inlet edge (11) and an outlet edge (12), wherein the inlet edge (11) is close to the central axis (Z), and the outlet edge (12) is far from the central axis (Z); The inlet edge (11) comprises a first curved segment (111) and a second curved segment (112) which are smoothly connected, the first curved segment (111) is an inwardly concave curved segment, and the second curved segment (112) is an outwardly convex curved segment; the outlet edge (12) comprises a third curved segment (121), and the third curved segment (121) is an inwardly concave curved segment.

2. The blade according to claim 1, characterized in that The blade (1) comprises a blade tip (13) and a blade root (14); an end of the first curved segment (111) away from the second curved segment (112) is connected to the blade tip (13), and an end of the second curved segment (112) away from the first curved segment (111) is connected to the blade root (14); a connection point P of the first curved segment (111) and the second curved segment (112) is located between 1 / 2L and 3 / 4L of the blade (1); wherein L is the extension length of the blade (1) from the blade root (14) to the blade tip (13), which is defined as 0 at the blade root (14) and defined as L at the blade tip (13).

3. The blade according to claim 2, characterized in that The projection of the central axis (Z) on the rotation surface of the blade (1) is the axis O; the connection point between the second curved segment (112) and the blade root (14) is E, and the projection point of the connection point E on the rotation surface of the blade (1) is E1; The point E1 and the axis O together form a reference line OE1, and the projections of the first curved segment (111) and the second curved segment (112) on the rotation surface of the blade (1) are respectively located on both sides of the reference line OE1.

4. The blade according to claim 3, characterized in that The connection point between the first curved segment (111) and the blade tip (13) is A, and the projection point of the connection point A on the rotation surface of the blade (1) is A1; at 3 / 4L of the blade (1), the projection of the first curved segment (111) on the rotation surface of the blade (1) is B1; At 1 / 2L of the blade (1), the projection of the second curved segment (112) on the rotation surface of the blade (1) is C1; at 1 / 4L of the blade (1), the projection of the second curved segment (112) on the rotation surface of the blade (1) is D1; Among them, the angle between the projection point A1 and the point E1 with the axis O as the angle is recorded as δa, the angle between the projection point B1 and the point E1 with the axis O as the angle is recorded as δb, the angle between the projection point C1 and the point E1 with the axis O as the angle is recorded as δc, and the angle between the projection point D1 and the point E1 with the axis O as the angle is recorded as δd; the ratio relationship of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:

6.

5. The blade according to claim 4, characterized in that At the blade tip (13), the wrap angle of the blade (1) is θa; at 3 / 4L of the blade (1), the wrap angle of the blade (1) is θb; at 1 / 2L of the blade (1), the wrap angle of the blade (1) is θc; At 1 / 4L of the blade (1), the wrap angle of the blade (1) is θd; at the blade root (14), the wrap angle of the blade (1) is θe; Among them, the ratio range of θa, θb, θc, θd, and θe is θa:θb:θc:θd:θe=1:(1-1.1):1.2:(1.2-1.3):(1.2-1.3).

6. The blade according to claim 5, characterized in that The value range of θa is 60°-100°.

7. A method for designing a blade, for obtaining a blade (1) as claimed in any one of claims 1 to 6, characterized in that: Includes steps: S1: defining an inlet edge (11), an outlet edge (12), a blade root (14) and a blade tip (13) of a basic blade, and obtaining at least five blade center lines of the basic blade, wherein the at least five blade center lines are distributed at equal intervals from the blade tip (13) to the blade root (14); S2: Obtaining the projection of the basic blade on the rotating surface, and defining the starting point and the end point of the at least five blade midlines in the projection of the basic blade; wherein the starting point of the blade midline is the end point of the blade midline at the inlet edge (11), and the end point of the blade midline is the end point of the blade midline at the outlet edge (12); S3: Taking the starting point E1 of the blade centerline located at the blade root (14) as the reference point and the axis O as the vertex, determine the ratio between the starting point of each blade centerline and the angle between E1 and the axis O, so that the inlet edge (11) presents an "S" shape; S4: determining the ratio of the wrap angles of the midlines of the blades so that the outlet edge (12) is in a "C" shape; S5: Determine the wrap angle value of any of the blade midlines, and determine the wrap angle values ​​of other blade midlines based on the ratio of the wrap angles of the blade midlines, thereby determining the shape of the blade (1).

8. The blade design method according to any one of claim 7, characterized in that: In step S1, the at least five blade center lines obtained include at least a blade center line (15) located at the blade top (13), a blade center line (16) located at 3 / 4L of the basic blade, a blade center line (17) located at 1 / 2L of the basic blade, a blade center line (18) located at 1 / 4L of the basic blade, and an e blade center line (19) located at the blade root (14); wherein L is the extension length of the basic blade from the blade root (14) to the blade top (13), which is defined as 0 at the blade root (14) and L at the blade top (13); In step S3, the angle between the starting point A1 of the center line of the a blade (15) and the point E1 with the axis O as the angle is recorded as δa, the angle between the starting point B1 of the center line of the b blade (16) and the point E1 with the axis O as the angle is recorded as δb, the angle between the starting point C1 of the center line of the c blade (17) and the point E1 with the axis O as the angle is recorded as δc, and the angle between the starting point D1 of the center line of the d blade (18) and the point E1 with the axis O as the angle is recorded as δd; the ratio relationship of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:6; In step S4, the wrap angle of the a-blade centerline (15) is θa, the wrap angle of the b-blade centerline (16) is θb, the wrap angle of the c-blade centerline (17) is θc, the wrap angle of the d-blade centerline (18) is θd, and the wrap angle of the e-blade centerline (19) is θe; wherein the ratio range of θa, θb, θc, θd, and θe is θa:θb:θc:θd:θe=1:(1-1.1):1.2:(1.2-1.3):(1.2-1.3).

9. A centrifugal wind wheel, characterized in that: include: A blade (1) as described in any one of claims 1 to 6; Or a blade (1) obtained by using the blade design method as claimed in claim 7 or 8.

10. A centrifugal fan, characterized in that: include: A blade (1) as described in any one of claims 1 to 6; or a blade (1) obtained by using the blade design method as described in claim 7 or 8; or a centrifugal wind wheel (10) as described in claim 9.

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