JP2000192898A - Propeller fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress fluctuation and advance of vortex generated by a tip end part and an end part of a blade by arranging a groove along a flow line on a negative pressure side blade surface of a downstream region of the tip end part of the blade. SOLUTION: A groove 11 is disposed on a negative pressure surface of a blade 5 of a propeller fan 2 along a flow line on a blade surface in a downstream region of a flange shaped blade tip end part 5d. The groove 11 may be formed from a blade tip end part 5d, a blade front end part 5a, and a blade outer peripheral part 5b to a blade rear end part 5c, or may be formed from the halfway. Horseshoe vortex 9 generated from the blade end and blade tip end vortex 8 generated from the blade tip end part are held along the blade 5 to the groove 11. Namely, the separating region 10 is small, and the horseshoe vortex 9 and the blade tip end vortex 8 flow along the blade 5. It is thus possible to suppress fluctuation and advance of the vortex, and it is also possible to prevent separation by pouring energy of the vortex held to the groove 11 to the separation region 10 on the blade surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propeller fan used for a blower or a ventilator for pumping a medium such as air for cooling or heating a working gas flowing in a heat exchanger of an air conditioner, and in particular, to a propeller fan. The present invention relates to a propeller fan suitable for lowering noise and increasing efficiency of a blower.

[0002]

2. Description of the Related Art FIG. 9 is a perspective view of a main part of a conventional blower. The main part of the blower 1 is a propeller fan 2
And Bellmouth 3. The propeller fan 2 includes a cylindrical boss 4 and a plurality of blades 5, and a plurality of blades 5 are provided at equal intervals along the circumferential direction of the outer peripheral surface of the boss 4. When the positive direction of the central axis 6 of the boss 4 is determined in the arrow direction P, the wing 5 forms a left-hand twisted surface with respect to the P direction. This wing 5
Is formed by a front edge 5a, an outer edge 5b, a rear edge 5c and a front connection portion, that is, a wing tip portion 5d and a rear connection portion 5e that smoothly connect the respective edges in addition to the outer surface 4a of the boss 4. Generally, the wing tip 5d has a sickle-like shape, and the outer edge 5b
Has a constant radius with respect to the shaft 6 and a diameter d.

The bell mouth 3 is a plate-like body provided with an arc-shaped orifice 7 having a thickness t and a predetermined gap ε with respect to the outer diameter d of the propeller fan 2. The bell mouth 3 and the propeller fan 2 are coaxially fixed by an appropriate means, and the propeller fan 2 is driven by driving means (not shown) such as an electric motor, an internal combustion engine, and a pulley.

[0004] When the propeller fan 2 rotates rightward as shown by the white arrow N, a flow in the forward direction P of the center axis 6 is generated from the upstream E to the downstream F. The propeller fan 2 of this type generally has a structure in which the thickness t of the orifice 7 is reduced and the blades 5 protrude to the upstream side in order to obtain a large air volume at a low static pressure, that is, to improve the blowing performance.

This situation is shown in FIG. 10 which is a BB development view from the outside toward the center along the circumferential direction in FIG. In FIG. 10, reference numeral 7 a denotes a front edge of the orifice 7 and also a front edge of the bell mouth 3. 7b is the orifice 7
And the orifice 7 has a band shape of width t, and the wing 5
Are projected at equal intervals according to the number of blades. Lf,
Lb indicates the amount of protrusion of the wing 5 with respect to the leading edge 7a and trailing edge 7b of the orifice 7, respectively, and it can be seen that the wing 5 largely projects with respect to the orifice leading edge 7a.

When the propeller fan 2 is made of resin, the boss 4 and the wing 5 are generally formed integrally, but the boss 4
Also, when the wing 5 and the wing 5 are processed separately and assembled together, the material is selectively used depending on the application. In either case,
The cross section of the outer edge 5b of the blade 5 in the thickness direction of the blade has a sharp shape to the extent that deburring has been performed. This situation is shown by CC in FIG.
FIG. 11 is a cross-sectional view.

[0007]

In the conventional blower 1 described above, most of the tip 5d and the outer edge 5b of the wing 5 protrude from the thickness of the bell mouth 3, and FIG.
Since the angle of attack 流 れ with respect to the flow of the wing 5 is large as shown in FIG.
This tends to develop along the streamline on the blade surface of the blade 5 and downstream of the blade tip 5d as shown in FIG. Also,
Due to the pressure difference between the upstream surface (vacuum surface) and the downstream surface (vacuum surface) of the flow in the wing 5, a secondary flow is generated in which the flow goes from the pressure surface to the vacuum surface, which develops and is shown in FIG. Such a wing tip vortex (horse-shoe vortex) 9 tends to occur.

As shown in FIG. 12, the wing tip vortex 8 and the horseshoe vortex 9 generated upstream of the tip portion and the outer edge of the wing 5 flow downstream respectively, and fluctuate and develop on the suction surface of the wing 5, and furthermore, Passing while interfering.

When operating at a relatively high static pressure operating point, that is, at an intermediate pressure range and a high pressure range, the separation region 10 largely develops from the trailing edge 5c of the blade 5 to the outer surface 4a of the boss 4. 10), which is a major cause of noise generation. This can be seen from the measurement results of the average wind speed distribution immediately after the fan shown in FIG. However, FIG. 13 shows the axial wind velocity V immediately after the fan as a dimensionless wind velocity that is dimensionlessly displayed with the fan tip wind velocity Ut. Further, the wing tip vortex 8 and the horseshoe vortex 9 are turned up by the influence of the separation region, and collide with the bell mouth 3 or flow between the wings and collide with the next wing 5, thereby causing further turbulence and pressure fluctuation. This causes a problem that noise is generated.

In order to solve the above-mentioned problems, the present invention suppresses the fluctuation and development of the vortex generated from the wing tip and the wing tip by appropriately adjusting the shape of the wing central portion of the propeller fan, and interferes with the bellmouth and the wing. While reducing the sound, preventing peeling on the wing surface,
It is an object of the present invention to provide a propeller fan capable of increasing air flow and increasing efficiency.

[0011]

According to a first aspect of the present invention, there is provided a propeller fan, comprising:
It is characterized in that a groove is provided along the streamline.

A propeller fan according to a second aspect of the present invention is the propeller fan according to the first aspect, wherein the distance from the center of rotation of the fan to the outer periphery of the groove is r, the radius of the fan is R, and the dimensionless groove position is λ = r /. R, this dimensionless groove position λ
Is set in the range of 0.40 ≦ λ ≦ 0.98.

According to a third aspect of the present invention, there is provided a propeller fan according to the second aspect, wherein the dimensionless groove position λ is set in a range of 0.50 ≦ λ ≦ 0.64.

According to a fourth aspect of the present invention, there is provided a propeller fan according to the second aspect, wherein the dimensionless groove position λ is set in a range of 0.60 ≦ λ ≦ 0.76.

According to a fifth aspect of the present invention, in the propeller fan according to the second aspect, the dimensionless groove position λ is set in a range of 0.74 ≦ λ ≦ 0.84.

A propeller fan according to a sixth aspect of the present invention is the propeller fan according to the third to fifth aspects, wherein a groove is further formed outside the groove formed at the non-dimensional groove position, and a non-dimensional groove position λ of the outer groove is formed. Is set in the range of 0.86 ≦ λ ≦ 0.96.

According to a seventh aspect of the present invention, there is provided a propeller fan according to the first aspect, wherein a plurality of grooves are provided.

[0018] The fluid feeder according to the eighth aspect is the first aspect.
A blower comprising the propeller fan according to any one of claims 7 to 7 and a drive motor for driving the propeller fan is provided.

In the propeller fan according to the present invention, a groove is formed along the streamline on the blade surface downstream of the sickle-shaped tip of the fan. Vortex (wing tip vortex) generated from the tip of the wing can be held to some extent, so that fluctuation and development of the vortex can be suppressed, interference noise with bell mouths and wings can be reduced, and the vortex is held in the groove By flowing the energy of the vortex into the separation area on the wing surface, separation can be prevented, and the air volume can be increased to increase the efficiency.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) A first embodiment according to the present invention will be described with reference to FIGS. 1A and 1B are diagrams of a propeller fan according to the present embodiment, wherein FIG. 1A is a front view, and FIG.
3 is a sectional view taken along the line AA of FIG.

In FIG. 1, the propeller fan 2 of this embodiment is provided with a groove 11 along the streamline on the suction surface of the blade 5 on the blade surface downstream of the sickle-shaped blade tip 5d. The rest is the same as the conventional example, and the description is omitted.

FIG. 2 is an aerodynamic characteristic diagram when the radial position r (the distance from the center of rotation of the fan to the outer periphery of the groove) of the groove 11 having a pressure coefficient of 0.19 is set to an optimum value. FIG. 4B is a diagram showing a pressure flow rate characteristic, and FIG. The operation and effect of the above-described configuration are as shown in FIG. 2, in which the air volume increases at the same static pressure, and thus the efficiency also improves. FIG. 3 is an axial wind speed distribution diagram immediately after the fan of the present embodiment when the position of the groove 11 is adjusted to the position where the maximum effect is exhibited at the operating point. As can be seen from this figure, it can be seen that the peeled area of the present embodiment is small.

The reason will be described with reference to FIG. FIG. 4 is an explanatory diagram of the behavior of the flow and the vortex on the wing surface of the present embodiment and the conventional example. As shown in FIG. 1, a groove 11 is formed along the streamline on the suction-side blade surface downstream of the sickle-shaped blade tip 5d of the fan 2, so that the horseshoe vortex 9 generated from the blade tip is formed in this groove. And the wing tip vortex 8 generated from the wing tip portion can be held along the wing 5 to some extent. FIG.
4B, the separation area 10 is smaller than in the conventional example, and the horseshoe vortex 9 and the wing tip vortex 8 flow along the wing 5. This is the vortex fluctuation,
This is because the growth was suppressed and the energy of the vortex held in the groove 11 was poured into the separation region 10 on the blade surface, thereby preventing separation.

Here, the radial position of the groove 11 at the blade trailing edge 5c (the distance from the center of rotation of the fan to the outer periphery of the groove 11) is r, the radius of the fan is R, and the position of the groove is the fan radius. It is assumed that the dimensionless groove position λ = r / R displayed dimensionlessly. When the dimensionless groove position λ was set in the range of 0.40 ≦ λ ≦ 0.98, the effects of large noise reduction and high efficiency were recognized.

Further, when the dimensionless groove position λ was set in the range of 0.50 ≦ λ ≦ 0.64, a great effect of reducing noise and increasing efficiency during operation in a low pressure range was recognized.

Further, when the dimensionless groove position λ was set in the range of 0.60 ≦ λ ≦ 0.76, a large noise reduction and high efficiency were observed during operation in the medium pressure range.

Further, when the dimensionless groove position λ was set in the range of 0.74 ≦ λ ≦ 0.84, a great effect of noise reduction and high efficiency was observed during operation in a high pressure range.

It has been confirmed that when the groove is formed in the range of the dimensionless groove position λ, the noise value and the efficiency are improved as compared with the conventional fan. This is because not only the noise generated from the separation area could be reduced, but also the fluctuation and development of the wing tip vortex and the horseshoe vortex could be suppressed, and the interference sound with the bell mouth and the wing could be reduced.

The groove 11 may be formed from the blade tip 5d, the blade leading edge 5a and the blade outer peripheral portion 5b to the blade trailing edge 5c, or may be formed midway. In particular, in the case where the blade is formed to be thick and the blade cross section is formed into a blade shape as shown in FIG. 5, it is desirable to form the groove 11 from a downstream area from the maximum thickness position of the blade. The grooves 11 may be formed not only on the suction-side blade surface but also on the pressure-side blade surface as needed.

(Second Embodiment) A second embodiment according to the present invention will be described with reference to FIG. 6A and 6B are diagrams of the propeller fan according to the present embodiment, in which FIG. 6A is a front view, and FIG.
It is arrow A sectional drawing.

In FIG. 6, the propeller fan 2 of this embodiment is provided with two grooves 11 along the streamline on the suction surface of the blade 5 on the blade surface downstream of the sickle-shaped blade tip 5d. . Others are the same as the conventional example, and the description is omitted.

The inner groove of the fan of this embodiment is the groove shown in the first embodiment, and the dimensionless groove position of the outer groove is provided at a position of 0.86 ≦ λ ≦ 0.96. Since this position is the most convenient position for holding the horseshoe vortex 8, the growth of the horseshoe vortex is suppressed because the horseshoe vortex is held by the second groove immediately after the occurrence,
Not only can the accompanying noise be reduced, but also the horseshoe vortex in the second groove and the wing tip vortex in the first groove separately, so that noise due to interference between the vortices can be further reduced.

The groove 11 may be formed from the blade tip 5d, the blade leading edge 5a and the blade outer peripheral portion 5b to the blade trailing edge 5c, or may be formed midway. In particular, when the blade is formed to be thick and the blade has a blade shape as shown in FIG. 5, it is desirable to apply the groove 11 to the groove 11 from a downstream region from the maximum thickness position of the blade. The grooves 11 may be formed not only on the suction-side blade surface but also on the pressure-side blade surface as needed.

(Third Embodiment) A third embodiment according to the present invention will be described with reference to FIG. 7A and 7B are diagrams of the propeller fan according to the present embodiment, in which FIG. 7A is a front view, and FIG.
It is arrow A sectional drawing.

In FIG. 7, the propeller fan 2 of this embodiment has a large number of grooves 11 along the streamline on the wing surface downstream of the tip 5d of the sickle-shaped wing on the suction surface of the wing 5. Others are the same as the conventional example, and the description is omitted.

The groove 11 in the fan of the present embodiment is the first groove.
A large number of grooves 11 shown in the embodiment are provided at narrow intervals. Therefore, the propeller fan described in the first and second embodiments can have the features to some extent, and can reduce noise and increase noise when operating at various operating points such as low-pressure operation, medium-pressure operation, and high-pressure operation. Can be more efficient. Therefore, it is effective in an environment where the operating point changes every moment.

The groove 11 may be formed from the blade tip 5d, the blade leading edge 5a and the blade outer peripheral portion 5b to the blade trailing edge 5c, or may be formed midway. In particular, when the wing is formed to be thick and the wing cross-sectional shape is as shown in FIG. 5, it is desirable to form the groove 11 from the downstream region from the maximum thickness position of the wing. Any number of the grooves 11 may be provided, and the grooves 11 may be provided not only on the suction-side wing surface but also on the pressure-side wing surface as needed.

(Fluid Feeding Device) Next, an embodiment of the fluid feeding device according to the present invention will be described. FIG. 8 is a configuration diagram illustrating the blower 1 in the main body of the outdoor unit 12 of the air conditioner. The fluid feeder includes a blower 1 including a propeller fan 2 and a drive motor 13 according to the first embodiment, and is configured to send out fluid by the blower 1. Examples of the fluid feeder having such a configuration include an air purifier, a humidifier, a fan heater, a cooling device, and a ventilator. The fluid feeder of the present embodiment is the outdoor unit 12 of the air conditioner. . An outdoor heat exchanger 14 is provided in the outdoor unit 12, and heat is efficiently exchanged by the blower 1.

Since the outdoor unit 12 of the present embodiment includes the propeller fan 2 of the first embodiment, it is a quiet outdoor unit with reduced noise. In addition, since the propeller fan 2 has improved fan efficiency, the propeller fan 2 is an efficient outdoor unit that achieves energy saving.

[0041]

The present invention has the following effects because it is configured as described above.

That is, according to the first to seventh aspects of the present invention, the fluctuation and development of the wing tip vortex and the horseshoe vortex, the interference with the bellmouth and the wing, and the separation on the wing surface can be prevented. Therefore, a quiet and highly efficient propeller fan can be obtained.

In particular, according to the third aspect of the present invention, there is provided a propeller fan optimized for low noise and high efficiency during operation in a low pressure range.

In particular, according to the fourth aspect of the present invention, there is provided a propeller fan which has been optimized for low noise and high efficiency during operation in a medium pressure range.

In particular, according to the fifth aspect of the present invention, it is possible to obtain a propeller fan optimized for low noise and high efficiency during operation in a high pressure range.

According to the sixth aspect of the present invention, since the horseshoe vortex and the wing tip vortex can be separately held, noise due to mutual vortex interference can be reduced to some extent, and the effect of noise reduction can be further obtained. A quiet and highly efficient propeller fan can be obtained.

According to the seventh aspect of the present invention, since the propeller fan according to the third to sixth aspects can be combined with the features to some extent, noise reduction and high efficiency can be achieved during operation at various operating points. The effect of conversion is recognized. Therefore, a propeller fan that is advantageous in both noise and efficiency under an environment where the operating point changes every moment is obtained.

The fluid feeder according to the eighth aspect is constituted by the blower provided with the propeller fan according to any one of the first to seventh aspects, so that good efficiency and energy saving are achieved. The noise is low.

[Brief description of the drawings]

FIG. 1A is a front view of a propeller fan according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view of the propeller fan according to the first embodiment of the present invention taken along line AA of FIG. It is.

FIG. 2 is an aerodynamic characteristic diagram when the radial position r of the groove at the pressure coefficient of 0.19 of the propeller fan according to the first embodiment of the present invention is set to an optimum value.

FIG. 3 is an axial wind speed distribution diagram immediately after the propeller fan according to the first embodiment of the present invention, in which the position of the groove is adjusted to a position where the maximum effect is exhibited at the operating point.

FIG. 4 is an explanatory diagram of the behavior of a flow and a vortex on a wing surface of the present embodiment and a conventional example.

FIG. 5 is an example of a wing cross-sectional shape.

FIG. 6A is a front view of a propeller fan according to a second embodiment of the present invention, and FIG. 6B is a cross-sectional view of the propeller fan according to the second embodiment of the present invention, taken along line AA of FIG. It is.

FIG. 7A is a front view of a propeller fan according to a third embodiment of the present invention, and FIG. 7B is a cross-sectional view of the propeller fan according to the third embodiment of the present invention taken along line AA of FIG. It is.

FIG. 8 is a configuration diagram showing one embodiment of a fluid feeder of the present invention.

FIG. 9 is a perspective view of a conventional blower.

FIG. 10 is an explanatory diagram of a wing tip vortex and a horseshoe vortex flow between wings in a conventional blower.

FIG. 11 is a schematic view of a wing tip vortex in a conventional blower.

FIG. 12 is a schematic diagram of a wing tip vortex and a horseshoe vortex on a suction surface in a conventional blower.

FIG. 13 is an axial wind speed distribution diagram immediately after a fan of a conventional blower.

[Explanation of symbols]

 2 Propeller fan 4 Boss 4a Boss outer surface 5 Blade 5c Blade trailing edge 5d Blade tip 11 Groove r Radial position of groove R Radius of fan

Claims (8)

[Claims] 1. A propeller fan, wherein a groove is formed along a streamline on a suction-side blade surface downstream of a blade tip. 2. The propeller fan according to claim 1, wherein the distance from the center of rotation of the fan to the outer periphery of the groove is r, the radius of the fan is R, and the dimensionless groove position is λ = r / R. A propeller fan, wherein the dimension groove position λ is set in the range of 0.40 ≦ λ ≦ 0.98. 3. The propeller fan according to claim 2, wherein the dimensionless groove position λ is set in a range of 0.50 ≦ λ ≦ 0.64. 4. The propeller fan according to claim 2, wherein the dimensionless groove position λ is set in a range of 0.60 ≦ λ ≦ 0.76. 5. The propeller fan according to claim 2, wherein the dimensionless groove position λ is set in a range of 0.74 ≦ λ ≦ 0.84. 6. The propeller fan according to claim 3, wherein a groove is formed further outside the groove formed at the dimensionless groove position, and the dimensionless groove position λ of the outer groove is set to 0.86 ≦ λ. A propeller fan set in the range of ≦ 0.96. 7. The propeller fan according to claim 1, wherein a plurality of grooves are provided. 8. A fluid feeder comprising a blower comprising the propeller fan according to claim 1 and a drive motor for driving the propeller fan.