An efficient and energy-saving L-shaped fan blade

Abstract

An efficient and energy-saving L-shaped fan blade of the present invention relates to the field of aerodynamics, especially to the structural improvement technology of fan blades. It is characterized in that: the blade is composed of a blade root area and a blade tip area. The leading edge on the left side and the trailing edge on the right side of the blade are both arc-shaped. The leading edge is arc AOB, and the trailing edge is arc EDB. The length of the leading edge arc AOB is greater than the length of the trailing edge arc EDB. The blade tip area extends towards the trailing edge. The ratio of the extension length GH of the blade tip area to the width HF of the blade root area is 5:5 to 8. Three to seven vortex guide ribs are provided on the blade surface. The present invention effectively blocks the development of negative circumferential vorticity, thereby improving the aerodynamic performance of the fan and the flow field circulation ability. At the same time, the vortex guide ribs 3 enhance the aerodynamic load and centrifugal load capacity of the blade, preventing the blade from deforming.

Description

Technical Field

[0001] The present invention relates to the field of aerodynamics, and particularly to an improved technology for the structure of fan blades. Background Art

[0002] The principle of the fan blade blowing air is that when the fan blade rotates, it squeezes the air on the force-bearing surface in an oblique cutting manner and moves it in a direction perpendicular to the surface of the fan blade.

[0003] Currently, fan blades generally have a swept-back and twisted airfoil shape and are installed on the rotating hub at a certain inclination angle. For example, the fan blade structure (publication number: CN 207598574 U) is described in paragraph

[0011] of the specification: "The end of the air-cutting edge is a circular arc-shaped air-pressing blade foot; the angle b between the air-pressing blade foot and the horizontal axis of the hub is less than the angle a."

[0004] Another example is: an anti-deformation fan blade (publication number: CN 207049065 U), which is described in paragraphs

[0008] to

[0009] of the specification: "Each blade inclines towards the air outlet direction of the electric fan. Among them, the inclination angle of each blade is not less than 10 degrees."

[0005] Due to the different inclination angles of the blades and the direction of the trailing edge of the blades, complex vortices are generated. These complex vortices are randomly distributed in the near-wall region of the blades. The direct physical and mathematical relationship between the negative vortex distribution region and the number of negative vortices on the surface of the fan blade and the aerodynamic performance of the fan is pointed out in the vorticity dynamics theory. The vorticity includes two important parameters: the boundary vorticity (BVF) and the circumferential vorticity (CV). Vorticity is a vector. Positive vorticity does positive work in the flow field, improving the flow capacity of the flow field; negative vorticity does negative work, exacerbating the formation of vortices and reducing the flow capacity of the flow field. In a complex flow field, the circumferential vorticity cannot be fundamentally eliminated, but by blocking the diffusion path of the negative circumferential vorticity or changing its distribution region, the aerodynamic performance of the blade can be effectively improved.

[0006] Second, the fan blade needs to have a certain angle to push the air. The fan blade is made into a streamline shape to avoid unnecessary frictional loss of kinetic energy. The slight difference in the shape of the fan blade will affect the tip clearance and the flow angle of the air flow, which also increases the deformation of the blade under the combined action of aerodynamic load and centrifugal load. The deformation of the blade will cause the movement of the shock wave position, thereby affecting the performance and efficiency of the turbomachine, and even causing problems such as aeroelastic stability. Therefore, the shape of the fan blade is one of the most important parameters determining the performance of the fan. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects of the above-mentioned prior art, and this purpose is achieved through the following technical solutions:

[0008] A highly efficient and energy-saving L-shaped fan blade, the blade consisting of a blade root area 1 and a blade tip area 2, the leading edge 4 on the left side of the blade and the trailing edge 5 on the right side are both arc-shaped, the leading edge 4 is an arc AOB, the trailing edge 5 is an arc EDB, the length of the arc AOB of the leading edge 4 is greater than the length of the arc EDB of the trailing edge 5, the blade tip area 2 extends toward the trailing edge, the ratio of the extension length GH of the blade tip area 2 to the width HF of the blade root area 1 is 5:5-8, and three to seven vortex guide ribs 3 are provided on the surface of the blade.

[0009] Preferably, the symmetry axis of the arc AOB of the leading edge 4 is ray Y, the vertex of the arc AOB is point O, the vertical line of ray Y is ray X, and ray X passes through point O, and the parabolic function of the arc AOB is: 1.5≤X 2 / 2Y≤2, where Y is a positive number, and the length of arc AO in arc AOB is less than the length of arc OB.

[0010] Preferably, the symmetry axis of the arc EDB of the trailing edge 5 is ray M, the vertex of the arc EDB is point D, the perpendicular line of ray M is ray N, and ray N passes through point D, and the parabolic function of the arc EDB is: 2.5≤N 2 / 2M≤3.2, where M is a positive number.

[0011] Preferably: the degree of the angle K at which the ray Y intersects the ray M is 5° to 8°, the ray N intersects the ray Y to obtain line segments OR and RD, the intersection point of the ray N and the ray Y is point R, the length of the line segment OR is T, the length of the segment RD is P, and the positional relationship between the arc AOB and the arc EDB is: 4≤T / P ≤6.

[0012] Preferably: the vortex guide rib 3 is a concave-convex texture stamped on the surface of the wind blade, the number of the vortex guide ribs 3 is odd, the concave-convex directions of two adjacent vortex guide ribs 3 are opposite, each of the vortex guide ribs 3 is composed of two inclined surfaces in opposite directions, the degree of the angle V formed by each two inclined surfaces is 160°~178°, each inclined surface diffuses in an arc shape from the blade root area 1 to the blade tip area, the closer to the blade root area 1, the larger the degree of the angle V, and the arc-shaped opening diffused by each inclined surface is toward the side of the trailing edge 5.

[0013] Preferably, the heights of the leading edge 4 and the trailing edge 5 are greater than the height of the middle vortex guide rib 3 .

[0014] Preferably, the blade tip area 2 is curved upward in an arc shape, and the greater the length of the blade tip area 2, the greater the height of the curve, so the angle I between the blade tip area 2 and the bottom horizontal line of the blade root area 1 is 10° to 25°.

[0015] Preferably, the wind blades are installed on the hub in a horizontal direction, and each hub is installed with 3 to 9 wind blades.

[0016] The present invention adjusts and optimizes the structures of the leading edge 4, trailing edge 5, and tip region 2, especially the tip clearance and airflow angle problems generated between the leading edge 4 and trailing edge 5. A new structural concept is proposed for the parabolic function and positional relationship between the leading edge 4 and trailing edge 5, effectively blocking the development of negative circumferential vorticity. When the fan blade rotates, the air in the upper tip region 2 is forced to "flow away", and the problem of negative pressure generated in the original root region 1. The negative pressure "flows into" the lower part of the vortex guiding rib 3 to form air flow, thereby improving the aerodynamic performance of the fan and the flow capacity of the flow field. At the same time, the vortex guiding rib 3 strengthens the aerodynamic load and centrifugal load capacity of the fan blade, preventing the deformation of the fan blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the present invention.

[0018] Figure 2 It is a schematic cross-sectional view of a-a of the present invention.

[0019] Figure 3 It is a schematic structural diagram of the parabolic function concept of the present invention.

[0020] Figure 4 It is a schematic implementation diagram of the present invention.

[0021] Reference numerals: 1-root region; 2-tip region; 3-vortex guiding rib; 4-leading edge; 5-trailing edge. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The specific embodiments of the present invention will be described below with reference to the accompanying drawings. Embodiment 1

[0023] As Figures 1-3 shown, an L-shaped fan blade with high efficiency and energy saving, the fan blade is composed of a root region 1 and a tip region 2. The leading edge 4 on the left side and the trailing edge 5 on the right side of the fan blade are both arc-shaped. The leading edge 4 is arc AOB, and the trailing edge 5 is arc EDB. The length of the arc AOB of the leading edge 4 is greater than the length of the arc EDB of the trailing edge 5. The tip region 2 extends towards the trailing edge. The ratio of the extension length GH of the tip region 2 to the width HF of the root region 1 is 5:8. Three to seven vortex guiding ribs 3 are provided on the surface of the fan blade.

[0024] The axis of symmetry of the arc AOB of the leading edge 4 is ray Y, the vertex of the arc AOB is point O, the perpendicular line of ray Y is ray X, and ray X passes through point O. The parabolic function of the arc AOB is: 1X 2 / 2Y = 1.5, where Y is a positive number. The specific function details are shown in Table 1. The length of the arc AO in the arc AOB is less than the length of the arc OB.

[0025]

[0026] The axis of symmetry of the trailing edge 5's arc EDB is ray M, the vertex of the arc EDB is point D, the perpendicular line of ray M is ray N, and ray N passes through point D. The parabolic function of the arc EDB is: 2.5 = N 2 / 2M, where M is a positive number. The specific function details are shown in Table 2.

[0027]

[0028] The degree of the included angle K formed by the intersection of the ray Y and the ray M is 5°. The ray N intersects with the ray Y to obtain the line segment OR and the line segment RD. The intersection point of the ray N and the ray Y is point R. The length of the line segment OR is T, and the length of the line segment RD is P. The positional relationship between the arc AOB and the arc EDB is: T / P = 6.

[0029] The vortex guide rib 3 is the concave-convex texture stamped on the surface of the wind blade. The number of the vortex guide ribs 3 is odd. The concave-convex directions of two adjacent vortex guide ribs 3 are opposite. Each vortex guide rib 3 is composed of two inclined planes with opposite directions. The degree of the included angle V formed by every two inclined planes is 160°. Each inclined plane diffuses in an arc shape from the blade root area 1 to the blade tip area. The degree of the included angle V is larger closer to the blade root area 1. The arc openings of each inclined plane diffusion are all towards one side of the trailing edge 5.

[0030] The heights of the leading edge 4 and the trailing edge 5 are greater than the height of the middle vortex guide rib 3.

[0031] The blade tip area 2 is warped upwards in an arc shape. The greater the extension length of the blade tip area 2, the greater the warping height. Therefore, the degree of the included angle I between the blade tip area 2 and the bottom horizontal line of the blade root area 1 is 10°.

[0032] The wind blade is installed on the hub in the horizontal direction. Each hub installs 3 wind blades Embodiment 2

[0033] As Figures 1-3 shown, a highly efficient and energy-saving L-shaped fan wind blade. The wind blade is composed of a blade root area 1 and a blade tip area 2. The leading edge 4 on the left side and the trailing edge 5 on the right side of the wind blade are both arc-shaped. The leading edge 4 is the arc AOB, and the trailing edge 5 is the arc EDB. The length of the arc AOB of the leading edge 4 is greater than the length of the arc EDB of the trailing edge 5. The blade tip area 2 extends towards the trailing edge. The ratio of the extension length GH of the blade tip area 2 to the width HF of the blade root area 1 is 5:8. There are three to seven vortex guide ribs 3 on the surface of the wind blade.

[0034] The axis of symmetry of the arc AOB of the leading edge 4 is ray Y, the vertex of the arc AOB is point O, the perpendicular line of ray Y is ray X, and ray X passes through point O. The parabolic function of the arc AOB is: X 2 / 2Y = 2, where Y is a positive number. The specific function is detailed in Table 3. The length of arc AO in arc AOB is less than the length of arc OB.

[0035]

[0036] The axis of symmetry of the trailing edge 5 arc EDB is ray M, the vertex of the arc EDB is point D, the perpendicular line of ray M is ray N, and ray N passes through point D. The parabolic function of the arc EDB is: N 2 / 2M = 3.2, where M is a positive number. The specific function is detailed in Table 4.

[0037]

[0038] The degree of the included angle K formed by the intersection of the ray Y and the ray M is 8°. The ray N intersects the ray Y to obtain the line segment OR and the line segment RD. The intersection point of the ray N and the ray Y is point R. The length of the line segment OR is T, and the length of the line segment RD is P. The positional relationship between the arc AOB and the arc EDB is: T / P = 4.

[0039] The guide vortex rib 3 is the concave-convex texture stamped on the surface of the wind blade. The number of the guide vortex ribs is odd. The concave-convex directions of two adjacent guide vortex ribs 3 are opposite. Each guide vortex rib 3 is composed of two inclined planes with opposite directions. The degree of the included angle V formed by every two inclined planes is 178°. Each inclined plane diffuses in an arc shape from the blade root area 1 to the blade tip area. The degree of the included angle V is larger closer to the blade root area 1. The arc opening of each inclined plane diffusion faces the side of the trailing edge 5.

[0040] The heights of the leading edge 4 and the trailing edge 5 are greater than the height of the middle guide vortex rib 3.

[0041] The blade tip area 2 is warped upward in an arc shape. The greater the extension length of the blade tip area 2, the greater the warping height. Therefore, the degree of the included angle I between the blade tip area 2 and the bottom horizontal line of the blade root area 1 is 25°.

[0042] The wind blade is installed on the hub in the horizontal direction. Nine wind blades are installed on each hub. Embodiment 3

[0043] As Figures 1-4 shown, a highly efficient and energy-saving L-shaped fan wind blade. The wind blade is composed of a blade root area 1 and a blade tip area 2. The leading edge 4 on the left side and the trailing edge 5 on the right side of the wind blade are both arc-shaped. The leading edge 4 is arc AOB, and the trailing edge 5 is arc EDB. The length of the leading edge 4 arc AOB is greater than the length of the trailing edge 5 arc EDB. The blade tip area 2 extends towards the trailing edge. The ratio of the extension length GH of the blade tip area 2 to the width HF of the blade root area 1 is 5:7. Three to seven guide vortex ribs 3 are provided on the surface of the wind blade.

[0044] The axis of symmetry of the front edge 4 arc AOB is the ray Y, the vertex of the arc AOB is the point O, the perpendicular line of the ray Y is the ray X, and the ray X passes through the point O. The parabolic function of the arc AOB is: X 2 / 2Y = 1.8, where Y is a positive number. The specific function is detailed in Table 5. The length of the arc AO in the arc AOB is less than the length of the arc OB.

[0045]

[0046] The axis of symmetry of the trailing edge 5 arc EDB is the ray M, the vertex of the arc EDB is the point D, the perpendicular line of the ray M is the ray N, and the ray N passes through the point D. The parabolic function of the arc EDB is: N 2 / 2M = 3, where M is a positive number. The specific function is detailed in Table 6.

[0047]

[0048] The degree of the included angle K formed by the intersection of the ray Y and the ray M is 6°. The ray N intersects the ray Y to obtain the line segment OR and the line segment RD. The intersection point of the ray N and the ray Y is the point R. The length of the line segment OR is T, and the length of the line segment RD is P. The positional relationship between the arc AOB and the arc EDB is: T / P = 5.

[0049] The guide vortex rib 3 is the concave and convex texture stamped on the surface of the wind blade. The number of the guide vortex ribs is odd, and the concave and convex directions of two adjacent guide vortex ribs 3 are opposite. Each guide vortex rib 3 is composed of two inclined planes with opposite directions. The degree of the included angle V formed by every two inclined planes is 170°. Each inclined plane diffuses in an arc shape from the blade root area 1 to the blade tip area. The degree of the included angle V is larger closer to the blade root area 1. The arc opening of each inclined plane diffusion faces the side of the trailing edge 5.

[0050] The heights of the front edge 4 and the trailing edge 5 are greater than the height of the middle guide vortex rib 3.

[0051] The blade tip area 2 is warped upward in an arc shape. The greater the extension length of the blade tip area 2, the greater the warping height. Therefore, the degree of the included angle I between the blade tip area 2 and the bottom horizontal line of the blade root area 1 is 15°.

[0052] The wind blade is installed on the hub in the horizontal direction. Each hub installs 5 wind blades.

[0053] The present invention adjusts and optimizes the structures of the leading edge 4, trailing edge 5, and tip region 2, especially the tip clearance and airflow angle problems generated between the leading edge 4 and trailing edge 5. A new structural concept is proposed for the parabolic function and positional relationship between the leading edge 4 and trailing edge 5, effectively blocking the development of negative circumferential vorticity, and solving the problem that the air in the upper tip region 2 flows away when the fan blade rotates while a negative pressure is generated in the original root region 1. The negative pressure "flows in" to the lower part of the vortex guide rib 3 to form an air flow, thereby improving the aerodynamic performance of the fan and the flow field circulation capacity. At the same time, the vortex guide rib 3 enhances the aerodynamic load and centrifugal load capacity of the fan blade, preventing the deformation of the fan blade.

[0054] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. An efficient and energy-saving L-shaped fan blade, characterized in that: The wind blade is composed of a root region (1) and a tip region (2). The leading edge (4) on the left side and the trailing edge (5) on the right side of the wind blade are both arc-shaped. The leading edge (4) is arc AOB, and the trailing edge (5) is arc EDB. The length of arc AOB of the leading edge (4) is greater than the length of arc EDB of the trailing edge (5). The tip region (2) extends towards the trailing edge. The ratio of the extension length GH of the tip region (2) to the width HF of the root region (1) is 5:5 - 8. Three to seven vortex guide ribs (3) are provided on the surface of the wind blade; The axis of symmetry of the arc AOB of the leading edge (4) is the ray Y, the vertex of the arc AOB is the point O, the perpendicular line of the ray Y is the ray X, and the ray X passes through the point O. The parabolic function of the arc AOB is: 1.5 ≤ X 2 / 2Y ≤ 2, where Y is a positive number, and the length of the arc AO in the arc AOB is less than the length of the arc OB; The axis of symmetry of the trailing edge (5) arc EDB is ray M, the vertex of the arc EDB is point D, the perpendicular line of ray M is ray N, and ray N passes through point D. The parabolic function of the arc EDB is: 2.5 ≤ N 2 / 2M ≤ 3.2, where M is a positive number; The degree of the included angle K formed by the intersection of the ray Y and the ray M is 5° - 8°. The ray N intersects the ray Y to obtain the line segment OR and the line segment RD. The intersection point of the ray N and the ray Y is point R. The length of the line segment OR is T, and the length of the line segment RD is P. The positional relationship between the arc AOB and the arc EDB is: 4 ≤ T / P ≤ 6; The vortex guide ribs (3) are concave-convex textures stamped on the surface of the wind blade. The number of the vortex guide ribs (3) is odd. The concave-convex directions of two adjacent vortex guide ribs (3) are opposite. Each vortex guide rib (3) is composed of two inclined planes with opposite directions. The degree of the included angle V formed by each two inclined planes is 160° - 178°. Each inclined plane diffuses in an arc shape from the root region (1) towards the tip region. The degree of the included angle V is larger closer to the root region (1). The arc opening of the diffusion of each inclined plane faces the side of the trailing edge (5).

2. The high-efficiency and energy-saving L-shaped fan blade according to claim 1, wherein: The heights of the leading edge (4) and the trailing edge (5) are greater than the height of the middle vortex guide rib (3).

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