KR100897133B1 - Cooling fan - Google Patents

Abstract

The present invention relates to a cooling fan that increases air volume and reduces noise, and includes a hub (12) and a plurality of blades (14) formed on an outer circumferential surface of the hub. When the airfoil is deformed at the trailing edge of the dimensionless radius (R) between 0 and 0.3, and the axial airfoil length is L1 and the deformation airfoil length is L2, the percentage of the deformation airfoil length [S = (L2 / L1) x 100] has wings of varying shape, decreasing from 25% to 0% in the dimensionless radius R of 0 to 0.3. According to this structure, the air volume of a cooling fan increases and noise is reduced.

Description

Cooling fan

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling fan, and more particularly, to a cooling fan that increases air volume and reduces noise by changing a shape of a blade.

The cooling fan is a blower that cools the cooling water of the car radiator and blows air to the air conditioner condenser to improve the system efficiency of the cooling system.The cooling fan has a plurality of wings extending radially from the hub and the outer periphery of the hub and blows the air axially. It is an axial fan.

Generally, the cooling fan consists of a circular hub 2 coupled to the drive shaft of the motor, and a plurality of vanes 4 extending radially around the hub 2. By enclosing each of the blades 4 and connecting the ends thereof, the air flowing in the radial direction is guided in the axial direction to increase the axial blowing efficiency and the blades 4 are mutually supported to deform the blades 4. The circular fan band 6 that can prevent the is optionally included.

In the configuration of the cooling fan, the blade draws air from the front of the cooling fan by using the pressure rise of the blade pressure surface during rotation, and pushes the air toward the rear of the cooling fan. It greatly affects the blowing efficiency and the flow noise.

Therefore, the shape, number, width, bending angle, mounting angle, etc. of the blade in the design of the cooling fan is an important design factor, various methods have been proposed to improve the performance of the cooling fan. The dimensionless radius R used in the design of the cooling fan is represented by the following equation.

R = (Ri-Rh) / (Rt-Rh)

Where Ri is the arbitrary radius of the blade, Rh is the hub radius, and Rt is the blade tip radius.

The blade is inclined in the opposite direction of rotation on the root of blade side in contact with the hub and in the rotational direction on the tip of blade side, which is the tip of the blade. In this case, the angle between the radial line passing from the hub center and the tangent of the arbitrary point is called a sweeping angle. The angle inclined in the rotational direction is referred to as a forward bending angle, and the angle inclined in the opposite direction of rotation is a backward bending angle. This is called. As shown in FIG. 2, the direction of rotation in the width of the wing is called a leading edge (LE), the direction of rotation in the opposite direction is called a trailing edge (TE), and the angle of the wing inclined with respect to the horizontal plane. Is called the setting angle (θs).

Since the flow of cooling fan is very complicated in three dimensions, it is designed by three-dimensional analysis, but the variable of performance (air volume, current, rotation speed, noise) is changed for one design variable, so it satisfies all variables. It is difficult to do.

In order to increase the blowing efficiency of the cooling fan and reduce the flow noise, US Patent No. 4,569,631 discloses a cooling fan having a bending angle of at least 30 degrees, and US Patent No. 4,684,324 radially centers the center of the circumferential blade width. Disclosed is a cooling fan having a blade whose midpoint of the midline (ML: mid-chord line) defined by connecting lines (points that change from backward bending angle to forward bending angle) is defined by the dimensionless radius (R) of 0.25 to 0.5. have. In addition, U.S. Patent No. 5,603,607 reduces the noise of the flow by reducing the strength of the vortex by making the trailing edge serrated, and Korean Patent No. 0761153 reduces the flow noise by forming a flow dispersion region in the leading and trailing edges.

As described above, the cooling fan mainly improves the blowing efficiency and reduces the noise by changing the shape of the blade, but there is a limit in defining each design element, and thus, satisfactory results are not obtained.

The present invention is to provide a cooling fan that deforms the trailing edge shape of the blade to clearly define the three-dimensional shape to increase the air volume and reduce the noise.

The cooling fan according to the present invention is a cooling fan having a hub and a plurality of blades formed on an outer circumferential surface of the hub, wherein the airfoil is formed in a range between 0 and 0.3 having a dimensionless radius (R) at the trailing edge of the blade. When the axial airfoil length is L1 and the deformation airfoil length is L2, the percentage of the deformation airfoil length [S = (L2 / L1) x 100] is in the range of the dimensionless radius R 0 to 0.3. At 25% to 0%, characterized by having a wing of varying shape.

The bending angle of the trailing edge of the blade is linearly increased in the opposite direction to the blade rotation from 0 to 0.3, the dimensionless radius (R) decreases in the blade rotation direction from 0.3 to 0.43, the dimensionless radius ( R) 0.43 to 1.0 increases nonlinearly in the direction of the blade rotation.

The bending angle of the leading edge of the blade, linearly increases in the anti-rotation direction of the blade radius (R) 0 to 0.3, nonlinearly decreases in the anti-rotation direction of the blade from the dimensionless radius (R) 0.3 to 0.62, The dimensionless radius (R) from 0.62 to 1.0 increases nonlinearly in the direction of the blade rotation.

According to the cooling fan according to the present invention, there is an effect of increasing the air volume and reducing the noise by deforming the trailing edge of the blade.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a front plan view of the cooling fan of the present invention, and FIGS. 4A to 4C are cross-sectional views taken along lines B1-B1, B2-B2, and B3-B3 of FIG. 3, and FIG. It is explanatory drawing for demonstrating the modified airfoil of this invention. As shown in Fig. 3, the cooling fan of the present invention comprises a circular hub 12 coupled to the drive shaft of the motor, and a plurality of vanes 14 extending radially around the hub 12. In addition, by enclosing each of the wings 14 and connecting the ends thereof, the air flowing in the radial direction is guided in the axial direction to increase the axial blowing efficiency and the wings 14 are mutually supported to deform the wings 14. A circular fan band 16 that can be prevented is selectively installed.

At the trailing edge (TE) of the wing, the airfoil C is deformed in the radial direction at the root of the blade contacting the hub. 4 and 5, the front surface of the blade 14 is a suction surface 14a, and the rear surface of the blade 14 is a pressure surface 14b. In FIG. 5, the horizontal length from the leading edge LE to the point where the deformed airfoil C is started is defined as an 'axial airfoil length L1', and the horizontal length of the deformed airfoil on the wing cross section is defined. When defined as 'strain airfoil length' (L2), the percentage of deformation airfoil length (S) is

S = (L2 / L1) x 100

The angle? C of the deformed airfoil length portion with the horizontal plane is the mounting angle of the deformed airfoil part. The dimensionless radius R is defined as R = (Ri-Rh) / (Rt-Rh) in accordance with Ri, Rh and Rt shown in FIG.

The blade of the present invention has a shape in which the airfoil is deformed in the range between 0 and 0.3 of the dimensionless radius R at the trailing edge. In the wing of the present invention, as shown in the graph of FIG. 6, the percentage of the deformation airfoil length (S) decreases to 25% to 0% in a range of 0 to 0.3 of the dimensionless radius (R). It is. Conventional blades in the region between the hub and the wing portion adjacent thereto, the respective flow in the pressure and suction surface of the wing is separated and recycled to the suction surface to generate severe disturbance, whereas the wing of the present invention due to the deformed airfoil Delamination of the flow at the pressure surface 14b and the suction surface 14a of the vane 14 is delayed to significantly reduce noise due to flow loss.

In addition, as shown in the graph of FIG. 7, the bending angle θt of the trailing edge of the blade of the present invention increases linearly in the direction opposite to the blade rotation from the dimensionless radius R to 0 to 0.3, and the dimensionless radius R ) 0.3 to 0.43 decreases in the direction of wing rotation, and dimensionless radius (R) 0.43 to 1.0 increases nonlinearly in the direction of wing rotation. This shape has a phase difference in which the position where the flow is introduced at the leading edge and the position at which the flow is separated at the trailing edge is minimized, thereby minimizing the loss to the vortex, and the boundary layer of the wing surface until R = 0.3. Flow noise is reduced by minimizing losses and boundary layer losses in hubs.

As shown in the graph of Fig. 8, the bending angle θl of the leading edge of the blade of the present invention increases linearly in the direction opposite to the blade rotation from dimensionless radius R to 0, and dimensionless radius R 0.3 to 0.62 decreases nonlinearly in the direction of anti-rotation of wings, and non-dimensional radius (R) increases from 0.62 to 1.0 nonlinearly in the direction of wing rotation. In the present invention, the shape is divided into three sections to minimize the flow resistance flowing into the wing.

In the graphs of Figs. 7 and 8, the bending angle of + represents the blade rotation direction, and the bending angle of − represents the blade rotation direction.

The mounting angle θs of the blade of the present invention decreases slowly from 0 to 0.3 in dimensionless radius R, and decreases almost linearly from 0.3 to 1.0 in dimensionless radius R as shown in FIG. There is a secondary flow between the wing and the wing, which is another type of flow in which some of the fluid is formed between the latter wing and not all of the fluid flows backwards from the front wing. The present invention optimizes the mounting angle to reduce the losses due to this secondary flow.

10 is a graph comparing the performance of the cooling fan of the embodiment of the present invention and the cooling fan of the conventional example. As indicated, based on the vehicle applied voltage 12v, the cooling fan of the present invention is increased by about 200 m 3 / h at the same rotational speed compared to the conventional cooling fan, the rotational speed is reduced by 120 RPM at the same flow rate, The required power is reduced by 30 W and the noise is reduced by 1.6 dB [A].

1 is a front plan view of a conventional cooling fan;

2 is a cross-sectional view taken along the line A-A in FIG.

3 is a front plan view of the cooling fan of the present invention;

4 (a) to 4 (c) are cross-sectional views taken along lines B1-B1, B2-B2, and B3-B3 in FIG. 3;

5 is an explanatory diagram for explaining a modified airfoil of the present invention;

Figure 6 is a graph comparing the percentage of the deformation airfoil length of the blade of the cooling fan of the present invention with the blade of the conventional cooling fan,

7 is a graph comparing the bending angle of the blade trailing edge of the present invention and the conventional cooling fan,

8 is a graph comparing the bending angle of the blade leading edge of the present invention and the conventional cooling fan,

9 is a graph comparing the mounting angle of the present invention and the conventional cooling fan,

10 is a graph comparing the performance of the present invention and the conventional cooling fan.

<Description of the symbols for the main parts of the drawings>

12 Hub 14 Wings

14a: suction surface 14b: pressure surface

16: band C: deformed airfoil

Claims (3)

In a cooling fan having a hub and a plurality of wings formed on the outer peripheral surface of the hub, When the airfoil deforms the airfoil at the trailing edge of the blade between 0 and 0.3, and the axial airfoil length is L1 and the deformation airfoil length L2, the percentage of the deformation airfoil length [S = ( L2 / L1) x 100] is a cooling fan, characterized in that the blade having a shape that is changed to decrease from 25% to 0% in the dimensionless radius (R) of 0 to 0.3. The method according to claim 1, The bending angle of the trailing edge of the blade, Dimensional radius (R) from 0 to 0.3 increases linearly in the direction of wing rotation, dimensionless radius (R) from 0.3 to 0.43 decreases in the direction of wing rotation, and dimensionless radius (R) from 0.43 to 1.0 turns Cooling fan, characterized in that it increases in a non-linear direction. The method according to claim 1 or 2, The bending angle of the leading edge of the blade, The dimensionless radius (R) from 0 to 0.3 increases linearly in the direction opposite to the wing rotation, and the dimensionless radius (R) from 0.3 to 0.62 decreases nonlinearly in the direction opposite the wing rotation, and the dimensionless radius (R) from 0.62 Cooling fan, characterized in that the non-linear increase in the direction of the blade rotation up to 1.0.

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