KR100446759B1 - Turbo fan - Google Patents

Abstract

In the present invention, the vertical projection surface has an airfoil shape, has a convex positive pressure surface and a concave negative pressure surface on both sides, and has a plurality of blades radially vertically installed between the main plate and the shroud, wherein the blade is a line On the basis of the string connecting the disadvantages and the trailing end point, by presenting a turbo fan characterized in that all the vertical projection surface is formed on one side of the string, the same or increased air volume can be generated, the same or reduced power consumption and Provided is a turbofan having a thinly formed blade to reduce manufacturing cost and manufacturing time and reduce the weight of the entire fan under the premise of generating noise.

Description

Turbo Fan {TURBO FAN}

The present invention relates to a turbofan, and more particularly, to a turbofan having a thin blade formed so as to reduce the production cost and manufacturing time under the premise of maintaining the same air flow rate and power consumption.

In general, the blowing fan is used as a means for conveying air by the rotational force of the van or rotor, and is applied to a refrigerator, an air conditioner, a vacuum cleaner, and the like.

In particular, the blower fan is classified into an axial fan, a sirocco fan, a turbo fan, and the like according to a method of suctioning and discharging air or its shape.

Among them, the turbo fan is a method of injecting air from the axial direction of the fan to the radial discharge between the blades, that is, through the side of the fan, since the air naturally flows into the fan and discharged to the outside, no duct is required, It is applied to relatively large products (such as ceiling mounted air conditioners).

1 to 3 show the structure of a conventional turbofan, Figure 1 is a plan view, Figure 2 is a side cross-sectional view, Figure 3 is a plan view showing a vertical projection surface of the blade.

As shown, a conventional turbofan has a main plate 1, a main plate 2 which forms a lower portion of the main body 1, and on which the fan motor 5 is installed, and around the inner surface of the main plate 2. A plurality of blades 3 are formed at regular intervals, and the shroud 4 is connected along the upper end of the blade 3.

An upper portion of the main body 1 is formed with an intake port 7 for sucking air, a central portion is formed with a flow path 6 for guiding the air in a direction to discharge the air, and a discharge hole for discharging the sucked air in the side portion. (8) is formed.

Therefore, when the main body 1 is rotated by the driving of the fan motor 5, the external air flows into the suction port 7 formed at the lower part of the main body by the rotation of the blade 3 formed integrally with the main body 1. The introduced air is discharged to the discharge port 8 side along the flow path 6.

On the other hand, the blade 3 has a vertical projection surface having an aerofoil shape, and has a convex positive pressure surface 31 and a concave negative pressure surface 32 on both sides, and is radial between the main plate 2 and the shroud 4. Vertically installed.

Here, the airfoil is a streamlined airfoil developed by NACA in 1950 and refers to a blade shape designed according to the following theory.

4 is a plan view showing a vertical projection surface of a blade installed in a conventional turbofan, and sets the front end point O, which is a vertex of the inner end of the blade, as the origin, and the rear end point that is the vertex of the origin and the outer end of the blade. The virtual straight line connecting (Z) is displayed on the Cartesian coordinate axis set as X axis.

The airfoil theory (NACA 4-Digit Aerofoil) applies a thickness function (yt) representing the thickness of the blade and a camberline function (yc) representing the parabola formed by the average value of the thicknesses. By using the following equation, the parabola formed by the positive and negative pressure surfaces of the blade is represented by a coordinate value.

First, the thickness function yt is the same as Equation 1.

The camber line function yc is expressed by Equation 2 below.

If is

If is

Here, M represents the Y coordinate of the maximum camber, and p represents the X coordinate of the maximum camber.

From these, the parabola 31 formed by the positive pressure surface of the blade can be expressed as in Equation (3).

,

here,

If is

If is

In addition, the parabola 32 formed by the negative pressure surface of the blade may be represented by Equation 4.

,

Here, the value of θ is the same as that of the parabola 31 formed by the positive pressure surface of the blade.

However, since the blade manufactured by the conventional method as described above has a thick thickness, it has been pointed out as a problem that the power consumption for generating the same air volume is large, and the generation of noise is large.

The present invention solves the above problems, and can produce the same or increased air flow, and on the premise of generating the same or reduced power consumption and noise, to reduce the manufacturing cost and manufacturing time and reduce the weight of the entire fan It is an object of the present invention to provide a turbofan having a blade thinly formed.

1 to 4 show the structure of a conventional turbofan,

1 is a plan view

2 is a side cross-sectional view

3 is a plan view showing the vertical projection surface of the blade;

4 is a plan view showing a vertical projection surface of a blade on a rectangular coordinate axis;

Figure 5 is a plan view showing a vertical projection surface of the blade according to the present invention

Figure 6 is a chart comparing the experimental performance of the blade according to the prior art and the present invention

7 is a plan view showing a vertical projection surface of another embodiment of a blade according to the present invention

** Explanation of symbols for main parts of drawings **

O: front end point Z: rear end point

C: string 31: positive pressure surface

34: negative pressure surface 35: partial negative pressure surface

In order to achieve the object described above, the present invention has a vertical projection surface having an airfoil shape, having a convex positive pressure surface and a concave negative pressure surface on both sides, and having a plurality of blades installed radially vertically between the main plate and the shroud. In one turbofan, the blade is based on the string connecting the front end and the rear end, all the vertical projection surface is formed on one side of the string and the blade is set to the starting point and the origin and the rear end The parabola forming the positive pressure surface of the vertical projection surface is based on the Cartesian coordinate axis that sets the virtual straight line connecting the X axis. , (here, If is If is In order to achieve the above object, the present invention provides a vertical projection surface that has an airfoil shape, and has a convex positive pressure surface and concave on both sides. A turbofan having a negative pressure surface and having a plurality of blades radially vertically installed between a main plate and a shroud, wherein the blades have all vertical projection surfaces of the strings relative to the strings connecting the leading and trailing ends. In addition to being formed on one side, the blade has a parabolic line forming the negative pressure surface of the vertical projection surface based on an orthogonal coordinate axis that sets an imaginary straight line connecting the origin and the trailing end to the X-axis and sets the front end to the origin. expression If is If is A turbofan is provided which is formed by the coordinates obtained by (wherein M represents the Y coordinate of the largest camber and p represents the X coordinate of the maximum camber).

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

5 is a plan view showing a vertical projection surface of the blade according to the present invention.

As shown, in the blade according to the present invention, all vertical projection surfaces are formed on the upper side of the string C, based on the string C connecting the front end O and the rear end Z.

Here, the front end point (O) refers to the vertex of the inner end of the blade in the vertical projection surface of the blade, the rear end (Z) refers to the vertex of the outer end of the blade.

This is in contrast to the conventional blade shown in FIG. 4 with respect to the string C connecting the front end point O and the rear end point Z, and a part of the vertical projection surface is formed below the string C. .

Therefore, only the parabola of the negative pressure 34 surface is moved upward while maintaining the parabolic shape of the conventional positive pressure surface 31 of the blade, and as a result, the thickness of the blade can be made thinner.

Figure 6 is a chart comparing the performance of the blade according to the conventional and the present invention, the reference numerals in parentheses (T, 0.75T, 0.5T) is the thickness of the blade according to the invention thinner based on the thickness of the conventional blade It means degree.

In the case of the blades according to the conventional blades (thickness T) and Example 1 (thickness 0.75T), the latter showed a slight disadvantage in terms of power consumption and noise, but considering that the blade thickness is reduced, It can be evaluated as showing the overall beneficial effect.

Here, the static pressure surface of the blade according to the present invention is formed by the above equation (3) to obtain the parabola formed by the static pressure surface 31 according to the conventional airfoil theory, the parabola of the conventional positive pressure surface 31 of the blade It is preferable in terms of moving only the parabola of the negative pressure surface 34 upward while maintaining the shape.

In the negative pressure surface 34 of the blade according to the present invention, it is preferable that the parabola formed by the negative pressure surface is formed by the coordinates obtained by the above expression (2).

That is, Equation 2 is a formula for obtaining a parabola constituting the camber line 33 in the conventional method, which has a meaning of defining a limit that can reduce the thickness of the blade according to the present invention.

As shown in FIG. 6, in the case of Example 2 (thickness 0.5T), it showed a slightly disadvantageous effect as compared with the case of the prior art and Example 1, but also considering that the thickness is also reduced by half, On the premise of maintaining almost the same performance, it can be said that the blade thickness was greatly reduced.

On the other hand, the two embodiments showed a slight adverse effect, but because some vortices occur at the front end of the blade, which can be solved by the following embodiment of the present invention It is.

That is, as shown in Figure 7, in the blade according to the present invention, based on the string (C) connecting the front end point (O) and the rear end point (Z), all the vertical projection surface on one side of the string (C) A body part 41 formed to be biased; A tip turbulence prevention portion 42 protruding on the tip portion negative pressure surface side of the body portion 41 to form a partial negative pressure surface 35; It is preferable to comprise.

The tip turbulence prevention portion 42 forms only the tip portion of the blade, which is an air inflow portion, to the same thickness as the conventional one, thereby reducing the thickness of the blade, which is the main element of the present invention, and at the same time, to maximize the disadvantageous effects such as vortex formation. It means to suppress.

Therefore, the tip turbulence prevention portion 42 is preferably formed by the parabola forming the partial negative pressure surface 35 by Equation 4 as in the conventional manner.

On the other hand, when the length of the string D of the tip turbulence prevention portion is too long, there is a fear that the basic idea of the present invention to reduce the thickness of the blade is faded.

Therefore, as a result of this experiment, it was found that the length of the string D of the tip turbulence prevention part is preferably 40% or less of the length of the string C of the body part.

The present invention is provided with a thinly formed blade to reduce the manufacturing cost and manufacturing time and reduce the weight of the entire fan, provided that the same or increased air volume can be generated and the same or reduced power consumption and noise are generated. Provide turbofans.

Claims (6)

delete A turbofan having a vertical projection surface having an airfoil shape, having a convex positive pressure surface and a concave negative pressure surface on both sides, and having a plurality of blades radially vertically disposed between the main plate and the shroud, The blade is based on the string connecting the front end and the rear end, all the vertical projection surface is formed on one side of the string and The blade has a parabola constituting the positive pressure surface of the vertical projection surface based on an orthogonal coordinate axis in which the front end point is set as the origin and the virtual straight line connecting the origin point and the rear end point is set in the X axis. , (here, If is If is to be) A turbofan, characterized in that formed by the coordinates obtained by. A turbofan having a vertical projection surface having an airfoil shape, having a convex positive pressure surface and a concave negative pressure surface on both sides, and having a plurality of blades radially vertically disposed between the main plate and the shroud, The blade is based on the string connecting the front end and the rear end, all the vertical projection surface is formed on one side of the string and The blade has a parabola constituting the negative pressure surface of the vertical projection surface based on an orthogonal coordinate axis that sets the front end point as the origin and sets the virtual straight line connecting the origin and the back end to the X axis. If is If is (Wherein, M represents the Y coordinate of the maximum camber, p represents the X coordinate of the maximum camber.) A turbofan, characterized in that formed by the coordinates obtained by. The method according to claim 2 or 3, The blade is A body part formed with all vertical projection surfaces biased to one side of the string, based on the string connecting the front and rear ends; A tip turbulence preventing portion protruding from the tip portion negative pressure surface side of the body portion to form a partial negative pressure surface; Turbo fan, characterized in that configured to include. The method of claim 4, wherein The blade is a parabola forming a partial negative pressure surface formed by the tip turbulence prevention portion of the vertical projection surface , (Here, the value of θ is the same as that of the parabola 31 formed by the positive pressure surface of the blade.) A turbofan, characterized in that formed by the coordinates obtained by. The method of claim 5, The length of the string of the tip turbulence prevention portion of the blade is less than 40% of the length of the string of the body portion.