WO2019035493A1 - Radial fan - Google Patents

Abstract

The present invention relates to a radial fan and, more specifically, to a radial fan having excellent mechanical stability and improved air flow. The radial fan comprises: a shroud having an inlet; a hub provided to be spaced from the shroud; a plurality of first blades radially distributed around the inlet; a plurality of second blades, which are shorter than the first blades in the radial direction, are respectively provided between the plurality of first blades and are radially distributed around the inlet; and a plurality of channels respectively formed between the plurality of first blades, wherein the channels guide air flowing in through the inlet so as to allow the air to be discharged to the outside through a discharge port.

Description

Radial fan

The present invention relates to a radial fan, more particularly, to a radial fan having excellent mechanical stability and improved air flow.

Radial blowers are used in a wide range of applications including industrial, electronic, and personal applications. Other air-positive pressure devices, such as, for example, cooling devices such as fans for cooling electronic components or providing air conditioning, and filtration devices often include radial blowers. Such a blower typically has a central inlet and an impeller that draws air through the inlet as it is rotated by the motor and pushes the air in a circular direction. Scrolls often provide a housing for blower components and include air passageways that wrap around the perimeter of the impeller. The impeller can push air out of the outlet through the air passage.

Many factors affect the efficiency, flow rate and pressure of the radial blower. For example, the shape and size of the scroll, the impeller design and size, the motor speed and output, and the fluid density both affect the efficiency and power of the radial blower. In some industrial applications, the design of a radial blower is driven by efficiency and power requirements, and shape and size are not important limiting factors. In an application in which the user includes a radial blower, for example, in other applications that carry a powered air purifying respirator, the size and shape of the blower may be particularly limited by ergonomic and transport considerations.

There is a need for a radial blower for use in a powered air purifier that can meet power and efficiency requirements while meeting the design constraints.

On the other hand, the study on the aerodynamic design of a fan or a blower as in the past has continued for several decades, and a lot of development has been made in the design technique. In recent years, however, the demand for noise as well as the performance has increased, and the production cycle of the product has been shortened, which necessitated the development of higher level design means.

In addition, as the technology of the industrial society develops day by day, the need for improvement of the noise source in the advanced society where the improvement of the quality of life is required due to the occurrence of the noise source varies according to the noise source, and the level is gradually increasing .

Although efforts have been made to improve the performance of blowers (fans) for industrial, automotive, office equipment, and household appliances, many attempts have been made to reduce noise, but due to many variables, It is difficult to evaluate the contribution and the design considering it.

Further, the background art of the present invention is disclosed in Korean Patent Laid-Open Publication No. 10-2001-0105617 (Nov. 30, 2001).

According to an embodiment of the present invention, there is provided a radial fan which improves the area of an air flow channel to optimize performance and efficiency of the fan.

It also provides a radial fan that optimizes the position of the blades and improves the shape of the blades to reduce mechanical stability and noise generation.

It also provides a radial fan that facilitates fabrication through the combination of an impeller, shroud, and hub.

According to an aspect of the present invention, there is provided a radial fan including a shroud having an inlet, a hub spaced apart from the shroud, a plurality of first blades radially distributed with respect to the inlet, A plurality of second blades radially shorter than the first blades and disposed radially between the first blades and radially distributed about the inlet, a plurality of channels being formed between the plurality of first blades , The channels guide the air introduced through the inlet port and discharge the air through the outlet port.

According to the embodiment of the present invention, the first blade forms a bend in the rotation direction and a bend in the rotation direction opposite to the rotation direction.

According to an embodiment of the present invention, the second blade forms a bend in the rotational direction and a bend in the opposite rotational direction.

According to an embodiment of the present invention, the plurality of second blade positions are randomly arranged in the rotating direction with respect to the center of the inlet port.

According to an embodiment of the present invention, the first blade and the second blade are coupled between the shroud and the hub.

According to an embodiment of the present invention, the width of the first blade is narrowed from the inlet side toward the outlet side.

According to an embodiment of the present invention, the width of the second blade is narrowed from the inlet side toward the outlet side.

According to an embodiment of the present invention, the shroud forms an inclination from the inlet toward the outlet.

According to an embodiment of the present invention, the hub has a center hole coupled to a rotary shaft at the center, and the center hole is curved convexly in the shroud direction.

And the inlet side surface area of the channels is set to be 1.5 to 2 times or less of the surface area of the channels on the side of the discharge port, according to an embodiment of the present invention.

A radial fan according to an embodiment of the present invention is an integral molded part made of a composite material, wherein the molded part is prevented from generating static electricity during operation or is discharged.

With such a configuration, the present invention can optimize the performance and efficiency of the fan by improving the area of the air flow channel. Further, the optimum position of the blade can be selected, and the shape of the blade can be improved to reduce mechanical stability and noise generation. Further, the combination of the impeller, the shroud, and the hub can facilitate fabrication.

According to the present invention having the above-described structure, it is possible to optimize the performance and efficiency of the fan by improving the area of the air flow channel.

Further, the optimum position of the blade can be selected, and the shape of the blade can be improved to reduce mechanical stability and noise generation.

Further, the combination of the impeller, the shroud, and the hub can facilitate fabrication.

1 is a perspective view of a radial fan according to an embodiment.

2 is a view for explaining an impeller design of a radial fan according to an embodiment.

3 is a cross-sectional view of a radial fan according to an embodiment.

4 is a longitudinal sectional view of the radial fan according to the embodiment.

5 is a view showing the channel area of the radial fan according to the embodiment.

Hereinafter, embodiments will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of each of the drawings, the same constituent elements are denoted by the same reference numerals even though they are shown in different drawings. In the following description of the embodiments, detailed description of known functions and configurations incorporated herein will be omitted when it may make the best of an understanding clear.

In describing the components of the embodiment, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be " connected, " " coupled, " or " connected. &Quot;

The components included in any one embodiment and the components including common functions will be described using the same names in other embodiments. Unless otherwise stated, the description of any one embodiment may be applied to other embodiments, and a detailed description thereof will be omitted in the overlapping scope.

FIG. 1 is a perspective view of a radial fan according to an embodiment of the present invention, FIG. 2 is a view for explaining a design of a radial fan according to an embodiment, FIG. 3 is a longitudinal sectional view of a radial fan FIG. 4 is a cross-sectional view of a radial fan according to an embodiment of the present invention, and FIG. 5 is a view showing a channel area of a radial fan according to an embodiment.

1 to 5, the radial fan includes a shroud 100 having an inlet 110, a hub 200 spaced apart from the shroud 100, and a radial fan A plurality of distributed first blades 300 are radially shorter than the first blades 300 and are disposed between a plurality of the first blades 300 and are radially distributed with respect to the inlet 110 A plurality of channels 500 are formed between a plurality of second blades 400 and a plurality of the first blades 300. The channels 500 guide the air introduced through the inlet 110 And discharges to the outside through the discharge port (600).

In general, the radial fan belongs to the low speed fan of the fan, and relatively high pressure is applied to the radial fan, the flow resistance is relatively large as in the fan unit, which is a part of the domestic boiler facilities, It can be applied.

More specifically, the shroud 100 is a donut-shaped circular disk having a hole at the center, and the center hole 210 may form an inlet 110 into which air flows. In addition, the shroud 100 may be inclined from the inlet 110 toward the outlet 600.

A plurality of first blades 300 and a plurality of second blades 400 are provided under the shroud 100. A plurality of first blades 300 and a plurality of second blades 400 are provided with a hub And a channel 500 through which the air flows is formed by the shroud 100, the first blade 300, the second blade 400, and the hub 200. In other words, the first blade 300 and the second blade 400 may be coupled between the shroud 100 and the hub 200.

A plurality of the first blades 300 may bend in the rotational direction and bend in the opposite rotational direction. Specifically, a plurality of first blades 300 are partially formed in a first direction in a rotational direction of the radial fan starting from one side, and a second bending in a direction opposite to the rotation of the radial fan And extend to the other side. In other words, the plurality of first blades 300 extend in the radial direction at the center of the radial fan, and can form an 'S' shaped double bend.

The plurality of second blades 400 may have a shorter length than the first blades 300 in the radial direction and may bend in the rotational direction and bend in the opposite rotational direction. Specifically, a plurality of the second blades 400 are partially formed in a first direction in a rotational direction of the radial fan starting from one side, and at a portion where the first bending ends, To the other side. In other words, the plurality of second blades 400 are formed to have a shorter length than the first blades 300 and extend in the radial direction, and can form an 'S' shaped double bend.

In addition, the first blades 300 may be arranged with a predetermined distance in the circumferential direction, and the second blades 400 may be positioned between the two first blades 300. In particular, the positions of the plurality of second blades 400 may be randomly arranged in the circumferential direction with respect to the center of the inlet 110.

2, the radial fan is provided with an impeller constituted by a backward blade. The main design variables include a cord length, a blade thickness, and a blade number, which are airfoil variables. The impeller shape parameters include an inlet angle, , Inlet height, and outlet height. Therefore, the impeller of the radial fan can be expressed in a two-dimensional shape in which the two-dimensional blades are piled up in the height direction. Here, the impeller may include the first blade 300 and the second blade 400.

Further, in a fluid machine in which a very large pressure is required, as in a compressor, among the radial fans, the shape of the impeller is such that the two-dimensional blades are not stacked in parallel from the hub 200 to the shroud 100, Impeller is used. That is, in the two-dimensional impeller, the stream surface around the blade is plane, while the stream surface around the blade has a curvature in the three-dimensional impeller, and the air flow toward the inlet port 110 is in the direction of the rotation axis And the air flow on the side of the discharge port 600 may have a generally radial direction.

However, in recent years, a high efficiency and low noise radial fan have been demanded, and the application of the impeller having the first blade 300 and the second blade 400 is attempted. In the same manner as used for the centrifugal compressor, And guide the air flow in the channel 500 from the inlet to the outlet of the second blade 400 and the outlet of the second blade 400. Particularly, since the second blade 400 guides the flow from the middle part of the impeller and slip occurs less, the efficiency is higher than that of a normal two-dimensional impeller.

As a non-dimensional parameter to be considered when designing the radial fan, there are a pressure coefficient and a flow meter which are dimensionless with the impeller diameter D2 and the number of revolutions N as pressure and flow rate as shown in the following Equation 1, pt and air volume Q have non-dimensional velocity and specific diameter.

Equation 1 is as follows.

Among these, specific speed is a non-dimensional variable representing a specific fan, and it is a frequently used parameter for comparing characteristics of fan, type, selection of impeller, and comparison of the same fan type.

 If the value of the non-velocity is large, the fan has a larger amount of air than the pressure rise amount. If the non-velocity is small, the pressure increase amount of the fan is higher than the air amount. Also, the impeller having a large non-velocity has a larger impeller outlet width than the diameter of the outlet, and the impeller having a smaller specific velocity may have a narrow outlet width.

 In the case of the impeller, the specific velocity is about 100 to 1000. In the case of 100 to 400, the specific speed is relatively low, and the case where the specific speed is 400 to 700 is mainly used. The specific diameter, δ, can be used as a good measure to determine the size (diameter) of the impeller during design.

The pressure rise of the impeller and the work by the Euler equation have the relationship expressed by Equation 2 below.

Equation 2 is as follows.

은 임펠러의 효율로서 내부 유동에 의한 전압 손실량에 대한 퍼센트(%)이다. here

Is the percentage of the voltage loss due to the internal flow as an efficiency of the impeller.

)을 구할 수 있고 임펠러 출구직경도 결정할 수가 있다. Therefore, assuming the efficiency of the impeller, the velocity component at the impeller outlet (

) And the diameter of the impeller outlet can be determined.

Generally, the flow from the impeller does not flow along the exit wing and slip occurs, so the outlet wing angle should be larger than the flow angle.

일 때 미끄러짐계수를 μ라고 하면,

이 되며 다음으로부터 출구 날개각도를 다음 식3과 같이 계산할 수 있다.Angle

Lt; RTI ID = 0.0 > μ, < / RTI >

And the angle of the exit wing can be calculated from the following equation (3).

Equation 3 is as follows.

The slip coefficient is expressed by the following Equation 4 using the Stodola equation.

Equation 4 is as follows.

Since the operating Mach numbers of most blowers are 0.1 to 0.3, they can be assumed to be incompressible flows. The inflow flow to the first blade 300 is inevitably made nonuniform due to the wake of the installed structure, and the resulting unsteady flow around the wing contributes to noise radiation. Also, the boundary layer around the rotating car is mainly a turbulent boundary layer, which ultimately causes very strong noise emission at the trailing edge of the first blade 300. Therefore, the noise in the radial fan is classified into inflow-turbulence noise, trailing edge noise, inflow vortex noise, and blunt-trailing edge noise. .

However, among these noise components, the most influential factor for the radial fan noise is the rear-end noise of the wing, and the turbulence around the impeller itself can not radiate a large amount of sound. However, when the turbulence caused by the quadrupole noise meets the rear end of the wing, .

배 만큼 원거리 강도가 증가한다. 여기서 ro는 임펠러 후단으로부터의 거리이며, 소음파장에 비해 훨씬 짧다고 가정된다. 또한 소음강도는 유동속도의 5승에 그리고 난류강도의 제곱, 후단 경계층두께 및 횡방향 상관거리에 비례하게 된다. This model of wing trailing noise was first developed by Ffowcs Williams and Hall in 1970, and according to them, both the longitudinal and lateral trapezoidal circles

The distance strength increases by a factor of two. Where ro is the distance from the rear end of the impeller and is assumed to be much shorter than the noise wavelength. Also, the noise intensity is proportional to the fifth power of the flow velocity and to the square of the turbulent intensity, the thickness of the downstream boundary layer, and the lateral correlation distance.

Further, a load (load) acting on the blade is a major cause of the radial fan noise. The most dominant of the unsteady load noises in the rotational and axial directions is the noise due to the load in the rotational direction.

The width of the first blade 300 decreases from the inlet 110 toward the outlet 600 and the width of the second blade 400 decreases from the inlet 110 toward the outlet 600. [ The width can be narrowed toward the discharge port 600 side.

The hub 200 is formed with a center hole 210 coupled to a rotating shaft at a center thereof and the center hole 210 can be curved convexly toward the inlet 110. Here, the hub 200 is formed in a disc shape in the circumferential direction about the rotation axis, and the center portion may be curved convexly toward the shroud 100.

The channel 500 is formed between two or more first blades 300 and has a plurality of circumferential radial shapes. The air introduced through the inlet 110 is discharged to the outside through the outlet 600 To guide the air flow. In addition, the second blade 400 is randomly disposed in a predetermined space in which the channel 500 is formed, and the space in the channel 500 can be divided into two parts by the second blade 400.

In other words, since the second blade 400 is randomly positioned rather than at a specific position in the channel 500, the entrance angle of the channel 500 is not constant and varies for each rotational direction position, Thereby reducing the air flow separation and slip between the channels 500 and allowing the phase of the air vortices passing through the channel 500 to be canceled.

The surface area of the channels 500 on the side of the discharge port 600 may be 1.5 to 2 times or less. In particular, the number of openings of the channel 500 by the second blades 400 may be 0.5 times the number of openings of the channel 500.

5, the second blades 400 may be disposed in the channel 500, but may not be disposed at regular intervals, but may be randomly disposed. Accordingly, since the phase of the second blade 400 is the same as the load applied to the second blade 400, the phase 1 is not constant, and the actual distance decreases as the average load decreases, so that the load noise can be reduced. However, as the repetitive phase? 2 increases, the effect of clogging one channel 500 appears and performance degradation is expected. Therefore, it may be required to use phases (φ1, φ2) within about 5 °.

Meanwhile, the radial fan is an integral molded part made of a composite material, and the molded part can prevent static electricity from being generated during operation or can be discharged.

Specifically, the shroud 100 and the hub 200 of the radial fan may be formed so that a circular shape is symmetrically formed in a circumferential direction about the rotation axis. The first blades 300 and the second blades 400 may be formed by directly forming the molded shroud 100 and the hub 200 on the entire length of the first blade 300 and the second blade 400, To be formed completely.

Accordingly, the radial fan according to the embodiment of the present invention is guided from the air flow and the inlet of the channel to the channel between the first and second blades 400, and the flow of the channel to the second blade 400 And the position of the second blade 400 is adjusted so as to improve the high efficiency condition in which the slip and the flow separation loss are reduced and the peak peak noise of the rear end of the first blade 300 due to the repeated load of the first blade 300 The torque balance is not constant in the circumferential direction, and noise reduction is achieved.

With such a configuration, the present invention can optimize the performance and efficiency of the fan by improving the area of the air flow channel. Further, the optimum position of the blade can be selected, and the shape of the blade can be improved to reduce mechanical stability and noise generation. Further, the combination of the impeller, the shroud, and the hub can facilitate fabrication.

Although the embodiments have been described with reference to the drawings, various technical modifications and variations may be applied to those skilled in the art. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Claims (12)

A shroud having an inlet; A hub disposed apart from the shroud; A plurality of first blades radially distributed with respect to the inlet; And A plurality of second blades radially shorter than the first blades radially and disposed between the plurality of first blades and distributed radially with respect to the inlet; Wherein a plurality of channels are formed between the plurality of first blades, and the channels guide the air introduced through the inlet and discharge the air through the outlet. The method according to claim 1, Wherein the first blade forms a bend in the rotational direction and a bend in the opposite rotational direction. The method according to claim 1, And the second blade forms a bend in the rotational direction and a bend in the opposite rotational direction. The method according to claim 1, And the plurality of second blade positions are randomly arranged in the rotation direction with respect to the center of the inlet port. The method according to claim 1, Wherein the first and second blades are coupled between the shroud and the hub. The method according to claim 1, Wherein the width of the first blade is narrower from the inlet side toward the outlet side. The method according to claim 1, And the width of the second blade is narrower from the inlet side toward the outlet side. The method according to claim 1, Wherein the shroud forms an inclination from the inlet to the outlet. The method according to claim 1, Wherein the hub has a central hole formed at a center thereof to be engaged with a rotary shaft, and the center hole is curved convexly in the shroud direction. The method according to claim 1, And the inlet side surface area of the channels is set to be 1.5 to 2 times or less of the surface area of the discharge port side. The method according to claim 1, Wherein the molded part is an integral molded part made of a composite material. 12. The method of claim 11, Wherein the molded part prevents static electricity from being generated or discharges during operation.

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