Design methods for blades, centrifugal impellers, centrifugal fans and blades

Abstract

This invention relates to the field of ventilation equipment technology, and discloses a design method for blades, centrifugal impellers, centrifugal fans, and the blades themselves. The blades are applied to a centrifugal impeller, which has a central shaft. The blades have an inlet edge and an outlet edge, with the inlet edge close to the central shaft and the outlet edge away from it. The inlet edge includes a first curved segment and a second curved segment that are smoothly connected; the first curved segment is concave, and the second curved segment is convex. The outlet edge includes a third curved segment, which is also concave. The design method for the blades, centrifugal impellers, centrifugal fans, and the blades of this invention can overcome the efficiency bottleneck of current centrifugal impellers, further improving their efficiency.

Description

Technical Field

[0001] This invention relates to the field of ventilation equipment technology, specifically to a design method for blades, centrifugal impellers, centrifugal fans, and blades. Background Technology

[0002] With the vigorous promotion of modernization, centrifugal wind turbines have found extremely wide applications. To fulfill their social responsibility of energy conservation and emission reduction, various application fields are increasingly emphasizing the efficiency improvement of centrifugal wind turbines. Among these components, the blades are a key part of the centrifugal wind turbine, directly affecting its efficiency.

[0003] However, in related technologies, due to the influence of the blade structure, during the process of airflow flowing from the inlet side of the blade to the outlet side, the kinetic energy of the airflow is dissipated in the form of internal energy, sound pressure, etc., which also makes it difficult to further improve the efficiency of centrifugal wind turbines in related technologies. Summary of the Invention

[0004] In view of this, the present invention provides a design method for blades, centrifugal impellers, centrifugal fans, and blades to solve the problem that the efficiency of centrifugal impellers is difficult to further improve in related technologies.

[0005] In a first aspect, the present invention provides a blade for use in a centrifugal impeller, the centrifugal impeller having a central shaft, the blade having an inlet side and an outlet side, the inlet side being close to the central shaft and the outlet side being far from the central shaft; wherein, the inlet side includes a first curved segment and a second curved segment that are smoothly connected, the first curved segment being a concave curve and the second curved segment being a convex curve; the outlet side includes a third curved segment, the third curved segment being a concave curve.

[0006] In one alternative embodiment, the blade has a apex and a root. The end of the first curved segment away from the second curved segment is connected to the apex, and the end of the second curved segment away from the first curved segment is connected to the root. The connection point P of the first and second curved segments is located between 1 / 2L and 3 / 4L of the blade. Wherein, L is the extension length of the blade from the root to the apex, defined as 0 at the root and L at the apex.

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

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

[0009] In one optional embodiment, the wrap angle of the blade is θa at the blade tip; θb at 3 / 4L of the blade; θc at 1 / 2L of the blade; θd at 1 / 4L of the blade; and θe at the blade root. The ratio 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 one optional implementation, θa ranges from 60° to 100°.

[0011] Secondly, the present invention also provides a blade design method for obtaining the blade as described above, comprising the following steps: S1: defining the inlet edge, outlet edge, blade root, and blade tip of a basic blade, and obtaining at least five blade centerlines of the basic blade, wherein the at least five blade centerlines are distributed at equal intervals from the blade tip to the blade root; S2: obtaining the projection of the basic blade onto the plane of rotation, and defining the start and end points of at least five blade centerlines in the projection of the basic blade; wherein the start point of the blade centerline is the endpoint of the blade centerline at the inlet edge, and the end point of the blade centerline is the endpoint of the blade centerline at the outlet edge; S3: taking the start point E1 of the blade centerline located at the blade root as the reference point and the axis O as the vertex, determining the ratio between the angle between the start point of each blade centerline and E1 with the axis O as the angle, so that the inlet edge presents an "S" shape; S4: determining the ratio 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 of the wrap angles of each blade centerline, thereby determining the shape of the blade.

[0012] In an optional implementation, in step S1, at least five blade centerlines are obtained, including at least blade centerline a located at the blade tip, blade centerline b located at 3 / 4L of the base blade, blade centerline c located at 1 / 2L of the base blade, blade centerline d located at 1 / 4L of the base blade, and blade centerline e located at the blade root; wherein, L is the extension length from the blade root to the base blade at the blade tip, defined as 0 at the blade root and L at the blade tip; in step S3, the angle between the starting point A1 of blade centerline a and point E1 with the axis O is denoted as δa, the angle between the starting point B1 of blade centerline b and point E1 with the axis O is denoted as δb, and the angle between the starting point A1 of blade centerline c and point E1 with the axis O is denoted as δb. The angle between point C1 and point E1 with the axis O as the angle is denoted as δc, and the angle between the starting point D1 of the blade centerline and point E1 with the axis O as the angle is denoted as δd; the ratio of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:6; in step S4, the wrap angle of the blade centerline is θa, the wrap angle of the blade centerline is θb, the wrap angle of the blade centerline is θc, the wrap angle of the blade centerline is θd, and the wrap angle of the blade centerline is θe; among which, 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] Thirdly, the present invention also provides a centrifugal impeller, comprising: blades as described above; or blades obtained using the blade design method described above.

[0014] Fourthly, the present invention also provides a centrifugal fan, comprising: blades as described above; or blades obtained using the blade design method described above; or centrifugal impellers as described above.

[0015] In the technical solution of the present invention, the inlet edge of the blade includes a first curved segment and a second curved segment that are smoothly connected. The first curved segment is a concave curved segment and the second curved segment is a convex curved segment, so that the inlet edge of the blade is shaped like an "S". The outlet edge of the blade includes a third curved segment, which is a concave curved segment, so that the outlet edge of the blade is shaped like a "C". The blades of this invention have an "S"-shaped inlet edge, exhibiting a phase difference distribution along the circumference of the centrifugal impeller. Similarly, the "C"-shaped outlet edge also exhibits a phase difference distribution along the circumference of the centrifugal impeller. This phase difference at the inlet edge alters the airflow characteristics at the blade inlet, creating a phase difference in the airflow angle of attack, thus suppressing negative effects such as pressure loss, impact loss, eddies, and noise. Furthermore, it synergistically optimizes the phase state of the flow within the blade passage, altering local pressure accumulation and kinetic energy mixing, thereby optimizing the entire power transfer process and improving the efficiency of the centrifugal impeller. Simultaneously, the phase difference at the inlet edge and the phase difference at the blade outlet spatially widen the spatial distance between the high and low kinetic energy outlet airflows, thereby suppressing flow field mixing at the blade outlet and reducing kinetic energy dissipation during mixing, further enhancing the efficiency of the centrifugal impeller. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

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

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

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

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

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

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

[0023] Explanation of reference numerals in the attached figures:

[0024] 10. Centrifugal impeller; 1. Blade; 11. Inlet edge; 111. First curved section; 112. Second curved section; 12. Outlet edge; 121. Third curved section; 13. Blade tip; 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, central axis. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The following is combined with Figures 1 to 6 The following describes embodiments of the present invention.

[0029] According to an embodiment of the present invention, in one aspect, a blade 1 applied to a centrifugal impeller 10 is provided, such as... Figure 1 As shown, the centrifugal impeller 10 has a central axis Z, and the blade 1 has an inlet edge 11 and an outlet edge 12. The inlet edge 11 is close to the central axis Z, and the outlet edge 12 is away from the central axis Z. The inlet edge 11 includes a first curved segment 111 and a second curved segment 112 that are smoothly connected. The first curved segment 111 is a concave curve, and the second curved segment 112 is a convex curve, 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 a concave curve, so that the outlet edge 12 of the blade 1 is shaped like a "C".

[0030] Understandably, the centrifugal impeller 10 includes multiple blades 1 arranged around the central axis Z and spaced apart along the circumference of the centrifugal impeller 10. Two connected blades 1 together form an air passage 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 air passage, and the outlet edge 12 is the outlet of the blade 1.

[0031] Using the blade 1 of the present invention, the inlet edge 11 of the blade 1 is S-shaped, exhibiting a phase difference distribution in the circumferential direction of the centrifugal impeller 10, and the outlet edge 12 is C-shaped, also exhibiting a phase difference distribution in the circumferential direction of the centrifugal impeller 10. The phase difference of the inlet edge 11 changes the airflow characteristics at the inlet of the blade 1, forming an airflow angle of attack phase difference, suppressing negative effects such as pressure loss, impact loss, eddies, and noise; and synergistically optimizing the phase state of the flow in the blade passage, changing local pressure accumulation and kinetic energy mixing, thereby optimizing the entire power process and improving 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 spatially widen the spatial distance between the high and low kinetic energy outlet airflows, thereby suppressing the formation of flow field mixing 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 impeller 10.

[0032] In the prior art, due to the limitations of the blade 1 structure, the upper limit of the single impeller efficiency of the centrifugal impeller 10 is usually around 75%. However, through practical verification, by using the blade 1 of the present invention, the upper limit of the single impeller efficiency of the centrifugal impeller 10 can be increased to 78%, which greatly improves the efficiency of the centrifugal impeller 10.

[0033] More specifically, in some embodiments, such as Figure 2 As shown, the blade 1 has a leaf tip 13 and a leaf root 14. The end of the first curved segment 111 away from the second curved segment 112 is connected to the leaf tip 13, and the end of the second curved segment 112 away from the first curved segment 111 is connected to the leaf root 14. 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. Here, L is the extension length of the blade 1 from the leaf root 14 to the leaf tip 13. For ease of description, the length at the leaf root 14 is defined as 0, and the length at the leaf tip 13 is defined as L. With this configuration, the first curve segment 111 near the blade tip 13 is a concave curve, and the second curve segment 112 near the blade root 14 is a convex curve. The airflow near the blade root 14 can enter the blade 1 first and do work first, while the airflow near the blade tip 13 enters the blade 1 later and does work later. This creates a time difference in work between the upper and lower parts of the blade 1, allowing the airflow to form an ideal phase difference in the angle of attack, thus optimizing the phase state of the flow in the blade passage and suppressing the mixing of the flow field at the exit of the blade 1.

[0034] Understandably, blade 1 typically has a certain thickness; therefore, 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 between the first curved segment 111 and the second curved segment 112 can be any point on the thickness direction of blade 1 where the first curved segment 111 and the second curved segment 112 meet. For example, the connection point P can be the intersection of the connection point of the first curved segment 111 and the second curved segment 112 with the blade centerline at that location.

[0035] In some embodiments, such as Figure 5 As shown, the projection of the central axis Z onto the plane of rotation of blade 1 is the axis O. This plane of rotation refers to any plane with the axis of rotation of blade 1, i.e., the central axis Z, as its normal. Figure 4 As shown, directions X, Y, and the central axis Z are all perpendicular to each other. The plane of revolution is any plane on the XY plane formed by directions X and Y. The axis O is the projection of the central axis Z onto the XY plane.

[0036] Furthermore, the connection point between the second curve 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 point of the blade centerline at the blade root 14 and the end of the second curve segment 112 away from the first curve segment 111.

[0037] Among them, the projection point E1 and the axis O together form the reference line OE1. The projections of the first curve segment 111 and the second curve segment 112 on the rotating surface of the blade 1 are 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 blade 1, in the extension direction of blade 1, specifically in the radial extension direction of blade 1 in the centrifugal impeller 10, that is... Figure 2 In the left-right direction, the first curved segment 111 protrudes from the leaf tip 13 and is recessed within the leaf root 14, and the second curved segment 112 protrudes from both the leaf tip 13 and the leaf root 14.

[0039] More specifically, in some embodiments, the connection point between the first curve 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 curve segment 111 on the rotation surface of the blade 1 is B1; at 1 / 2L of the blade 1, the projection of the second curve segment 112 on the rotation surface of the blade 1 is C1; at 1 / 4L of the blade 1, the projection of the second curve segment 112 on the rotation surface of the blade 1 is D1.

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

[0041] The angle between projection points A1 and E1 with respect to the axis O is denoted as δa, the angle between projection points B1 and E1 with respect to the axis O is denoted as δb, the angle between projection points C1 and E1 with respect to the axis O is denoted as δc, and the angle between projection points D1 and E1 with respect to the axis O is denoted as δd. The ratio of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:6. Under this ratio, the phase difference distribution at the inlet edge 11 of blade 1 can be accurately controlled, thereby accurately controlling the phase difference of the airflow angle of attack at the inlet edge 11. This results in better suppression of negative effects such as pressure loss, impact loss, eddies, and noise, ensuring the reliability of efficiency improvement. Meanwhile, since a phase difference is formed at the inlet edge 11 according to this ratio, the flow in the blade passage will also inevitably form a corresponding phase difference relationship. The airflow in the blade passage is affected by the phase difference, which optimizes the phase state, thereby optimizing the entire work process and improving the efficiency of the centrifugal impeller 10.

[0042] In some embodiments, the wrap angle of blade 1 is θa at the blade tip 13; θb at 3 / 4L of blade 1; θc at 1 / 2L of blade 1; θd at 1 / 4L of blade 1; and θe at the blade root 14. The ratio of θa, θb, θc, θd, and θe ranges from θa:θb:θc:θd:θe = 1:(1-1.1):1.2:(1.2-1.3):(1.2-1.3). Because the work capacity of the blade centerline differs at different locations on blade 1, the kinetic energy of the airflow exiting the blade passage differs significantly, resulting in flow field mixing at the exit and consuming a large amount of kinetic energy. By controlling the ratio of the aforementioned wrap angles within this range, a better effect can be achieved in suppressing flow field mixing at the outlet, thereby reducing kinetic energy consumption and maximizing the efficiency of the centrifugal impeller 10.

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

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

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

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

[0047] Specifically, such as Figure 6As shown, at the blade tip 13, the projection point of the third curve segment 121 onto the plane of rotation is A2; at 3 / 4L of blade 1, the projection of the third curve segment 121 onto the plane of rotation of blade 1 is B2; at 1 / 2L of blade 1, the projection of the third curve segment 121 onto the plane of rotation of blade 1 is C2; at 1 / 4L of blade 1, the projection of the third curve segment 121 onto the plane of rotation of blade 1 is D2; and at the blade root 14, the projection point of the third curve segment 121 onto the plane of rotation is E2. 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] Understandably, the above projection points A2, B2, C2, D2, and E2 can all be understood as the intersection of the blade centerline and the exit edge 12 at the corresponding positions.

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

[0050] According to an embodiment of the present invention, in another aspect, a method for designing a blade 1 is also provided for obtaining a blade 1 as described above, specifically including the following steps:

[0051] S1: Define the inlet edge 11, outlet edge 12, leaf root 14 and leaf tip 13 of the basic blade, and obtain at least five blade centerlines of the basic blade, which are equally spaced from the leaf tip 13 to the leaf root 14.

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

[0053] S3: Taking the starting point E1 of the blade centerline located at the leaf 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 centerlines of each blade so that the exit edge 12 is "C" shaped;

[0055] S5: Determine the wrap angle value of any blade centerline, and determine the wrap angle values ​​of other blade centerlines based on the ratio of the wrap angles of each blade centerline, thereby determining the shape of blade 1.

[0056] The blade 1 obtained by the design method of the present invention can effectively improve the efficiency of the centrifugal impeller 10. The method uses the ratio between the starting point of each blade centerline and the angle between E1 and the axis O, as well as the ratio of the wrap angle of each blade centerline to define the phase difference at the inlet side 11 and the outlet side 12. The shape of the blade 1 is not affected by the size of the blade 1 or the centrifugal impeller 10 to which it is applied. Therefore, regardless of the actual size of the blade 1 or the centrifugal impeller 10 to which it is applied, the efficiency of the centrifugal impeller 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 centerlines are obtained, including at least blade centerline 15 (a) located at the blade tip 13, blade centerline 16 (b) located at 3 / 4L of the base blade, blade centerline 17 (c) located at 1 / 2L of the base blade, blade centerline 18 (d) located at 1 / 4L of the base blade, and blade centerline 19 (e) located at the blade root 14. Here, L is the extension length of the base blade from the blade root 14 to the blade tip 13, defined as 0 at the blade root 14 and L at the blade tip 13. Understandably, throughout the design process, the positions and leaf surface shapes of the base blade's blade root 14 and blade tip 13 do not change, and the L of the base blade is also the L of the final obtained blade 1.

[0058] In some embodiments, in step S3, a) 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 denoted as δa; b) 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 denoted as δb; c) 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 denoted as δc; d) 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 denoted as δd; the ratio of δa, δb, δc, and δd satisfies δa:δb:δc:δd=-12:-5:5:6. Under the constraint of this ratio, the phase difference distribution at the inlet edge 11 of the blade 1 can be precisely controlled, thereby accurately controlling the airflow angle of attack phase difference at the inlet edge 11, thus achieving better suppression of negative effects such as pressure loss, impact loss, eddies, and noise, and ensuring the reliability of efficiency improvement. Meanwhile, since a phase difference is formed at the inlet edge 11 according to this ratio, the flow in the blade passage will also inevitably form a corresponding phase difference relationship. The airflow in the blade passage is affected by the phase difference, which optimizes the phase state, thereby optimizing the entire work process and improving the efficiency of the centrifugal impeller 10.

[0059] In some embodiments, in step S4, the wrap angle of blade centerline 15 is θa, the wrap angle of blade centerline 16 is θb, the wrap angle of blade centerline 17 is θc, the wrap angle of blade centerline 18 is θd, and the wrap angle of blade centerline 19 is θe; wherein the ratio 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). Controlling the above wrap angle ratio within this range can achieve a better effect of suppressing flow field mixing at the outlet, thereby reducing kinetic energy consumption and maximizing the efficiency of the centrifugal impeller 10.

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

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

[0062] a. Leaf midline 15 (leaf tip 13);

[0063] b. Blade centerline 16 (at 3 / 4L);

[0064] c. Blade centerline 17 (at 2 / 4L);

[0065] d. Blade centerline 18 (at 1 / 4L);

[0066] e. Leaf midline 19 (leaf root 14).

[0067] In this step, the centerline of each blade can be obtained by ternary design theory and CFD iteration.

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

[0069] S2: Obtain the projection of the basic blade onto the plane of revolution, and define the start and end points of 5 blade centerlines in the projection of the basic blade, as follows:

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

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

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

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

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

[0075] S3: Determine the phase relationship of the starting points of the centerlines of the five blades:

[0076] Point E1 is used as the phase reference;

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

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

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

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

[0081] Taking the inlet direction of blade 1 as positive and the outlet direction as negative, the phase relationship of each centerline starting point is as follows:

[0082] δa:δb:δc:δd=-12:-5:5:6.

[0083] After this step, the starting points of the centerlines of each blade are connected to form the first curve segment 111 and the second curve segment 112, that is, the inlet edge 11 of blade 1 presents an "S" shape.

[0084] S4: Determine the ratio of the wrap angles of the centerlines of each blade:

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

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

[0087] The angle between C1 and C2 about the axis O is defined as the wrap angle of the 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 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 centerlines of each blade are connected to form the third curve segment 121 mentioned above. That is, the exit edge 12 of blade 1 presents a "C" shape, and there is no need to constrain the phase relationship of the endpoints of the centerlines of each blade.

[0092] S5: Determine the wrap angle value of any blade centerline, and determine the wrap angle values ​​of other blade centerlines based on the ratio of the wrap angles of each blade centerline, thereby determining the shape of blade 1.

[0093] After steps S3 and S4 above, the shape of blade 1 still needs to determine the wrap angle value of a centerline (optional) to uniquely define it in the angular proportion relationship. At this point, regardless of how the size of the impeller changes, the proportional relationship between blade 1 and 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 to 5, and the corresponding value of θa is 60° to 100°.

[0094] Understandably, the design method of this invention only limits the angular relationship and does not limit the size of the blade 1. Therefore, the design method of this invention can be used for the design and application of blades 1 of centrifugal impellers 10 with the same or similar specific speeds. That is, regardless of the actual size of the blade 1 or the centrifugal impeller 10 to which it is applied, it is within the scope of this invention.

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

[0096] Specifically, such as Figure 1 As shown, the centrifugal impeller 10 includes a wheel cover 2, a wheel disk 3, and multiple blades 1. The blade tips 13 of the blades 1 are connected to the wheel cover 2, and the blade roots 14 of the blades 1 are connected to the wheel disk 3. The wheel cover 2 and the wheel disk 3 are both annular and coaxially arranged, sharing a common central axis Z, which is the rotation axis of the centrifugal impeller 10. The multiple blades 1 are spaced apart around the central axis Z, that is, spaced apart circumferentially around the wheel cover 2 and / or the wheel disk 3.

[0097] Each blade 1 has an inlet edge 11 and an outlet edge 12. 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 that are smoothly connected. The first curved segment 111 is a concave curve, and the second curved segment 112 is a convex curve, so that the inlet edge 11 of the blade 1 is S-shaped. The outlet edge 12 includes a third curved segment 121, which is a concave curve, so that the outlet edge 12 of the blade 1 is C-shaped.

[0098] According to an embodiment of the present invention, in another aspect, a centrifugal fan is also 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 impeller 10 as described above.

[0099] Since both the centrifugal impeller 10 and the centrifugal fan of the present invention 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 impeller 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 described again here.

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

Claims

1. A blade applied to a centrifugal impeller (10), the centrifugal impeller (10) having a central shaft (Z), characterized in that, The blade (1) has an inlet edge (11) and an outlet edge (12), the inlet edge (11) being close to the central axis (Z) and the outlet edge (12) being away from the central axis (Z). The inlet edge (11) includes a first curved segment (111) and a second curved segment (112) that are smoothly connected. The first curved segment (111) is a concave curve and the second curved segment (112) is a convex curve. The outlet edge (12) includes a third curved segment (121) that is a concave curve. The leaf (1) has a leaf tip (13) and a leaf root (14), the end of the first curved segment (111) away from the second curved segment (112) is connected to the leaf tip (13), and the end of the second curved segment (112) away from the first curved segment (111) is connected to the leaf root (14). The projection of the central axis (Z) onto the rotation surface of the blade (1) is axis O, and the rotation surface of the blade (1) is any plane with the central axis (Z) as the normal; the connection point between the second curve segment (112) and the blade root (14) is E, and the projection point of the connection point E onto the rotation surface of the blade (1) is E1. The connection point between the first curve segment (111) and the blade tip (13) is A, and the projection point of 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 curve segment (111) on the rotation surface of the blade (1) is B1; at 1 / 2L of the blade (1), the projection of the second curve segment (112) on the rotation surface of the blade (1) is C1; at 1 / 4L of the blade (1), the projection of the second curve segment (112) on the rotation surface of the blade (1) is D1; Wherein, L is the extension length of the leaf blade (1) from the leaf root (14) to the leaf tip (13), defined as 0 at the leaf root (14) and L at the leaf tip (13); Among them, taking point E1 as the phase reference, the inlet direction of the blade (1) is positive and the outlet direction is negative. The angle between the projection point A1 and point E1 with the axis O is denoted as δa, the angle between the projection point B1 and point E1 with the axis O is denoted as δb, the angle between the projection point C1 and point E1 with the axis O is denoted as δc, and the angle between the projection point D1 and point E1 with the axis O is denoted as δd. The ratio of δa, δb, δc and δd satisfies δa:δb:δc:δd=-12:-5:5:

6.

2. The blade according to claim 1, characterized in that, The connection point P of the first curve segment (111) and the second curve segment (112) is located between 1 / 2L and 3 / 4L of the blade (1).

3. The blade according to claim 1, characterized in that, Point E1 and the axis O together form the baseline OE1. The projections of the first curve segment (111) and the second curve segment (112) on the rotating surface of the blade (1) are located on both sides of the baseline OE1.

4. The blade according to claim 1, characterized in that, At the tip (13) of the blade, 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 leaf root (14), the wrap angle of the blade (1) is θe; 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).

5. The blade according to claim 4, characterized in that, The value of θa ranges from 60° to 100°.

6. A method for designing a blade, for obtaining a blade (1) as described in any one of claims 1-5, characterized in that, Including the following steps: S1: Define the inlet edge (11), outlet edge (12), leaf root (14), and leaf tip (13) of the basic blade, and obtain at least five blade centerlines of the basic blade, wherein the at least five blade centerlines are equally spaced from the leaf tip (13) to the leaf root (14); the at least five blade centerlines include at least the a-blade centerline (15) located at the leaf tip (13), the b-blade centerline (16) located at 3 / 4L of the basic blade, the c-blade centerline (17) located at 1 / 2L of the basic blade, and the d-blade centerline (18) located at 1 / 4L of the basic blade; wherein, L is the extension length of the basic blade from the leaf root (14) to the leaf tip (13), defined as 0 at the leaf root (14), and defined as L at the leaf tip (13); S2: Obtain the projection of the base blade on the rotating surface, and define the start and end points of the at least five blade centerlines in the projection of the base blade; wherein, the start point of the blade centerline is the endpoint of the blade centerline at the inlet edge (11), and the end point of the blade centerline is the endpoint of the blade centerline at the outlet edge (12). S3: Taking the starting point E1 of the blade centerline located at the leaf 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; taking point E1 as the phase reference, taking the inlet direction of the blade (1) as positive and the outlet direction as negative, the angle between the starting point A1 of the blade centerline (15) and point E1 with the axis O as the vertex is determined. The angle is denoted as δa, the angle between the starting point B1 of the centerline (16) of blade b and point E1 with the axis O is denoted as δb, the angle between the starting point C1 of the centerline (17) of blade c and point E1 with the axis O is denoted as δc, and the angle between the starting point D1 of the centerline (18) of blade d and point E1 with the axis O is denoted as δd; the ratio of δa, δb, δc and δd satisfies δa:δb:δc:δd=-12:-5:5:6; S4: Determine the ratio of the wrap angles of the centerlines of each blade so that the exit edge (12) is "C" shaped; S5: Determine the wrap angle value of any of the blade centerlines, and determine the wrap angle values ​​of the other blade centerlines according to the ratio of the wrap angles of each blade centerline, thereby determining the shape of the blade (1).

7. The blade design method according to claim 6, characterized in that, In step S1, the at least five blade midlines also include the e-blade midline (19) located at the leaf root (14). In step S4, the wrap angle of the centerline (15) of blade a is θa, the wrap angle of the centerline (16) of blade b is θb, the wrap angle of the centerline (17) of blade c is θc, the wrap angle of the centerline (18) of blade d is θd, and the wrap angle of the centerline (19) 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).

8. A centrifugal impeller, characterized in that, The blade (1) includes any one of claims 1-5; or the blade (1) obtained by the blade design method as described in claim 6 or 7.

9. A centrifugal fan, characterized in that, The blade (1) includes any one of claims 1-5; or the blade (1) obtained by the blade design method as described in claim 6 or 7; or the centrifugal impeller (10) as described in claim 8.

Images