阅读说明：本技术 一种轴流风机叶片及风机 (Axial fan blade and fan ) 是由 陈炜 曹浩 胡胜 周舟 周卫华 卢铃 黄韬 张万福 于 2021-10-22 设计创作，主要内容包括：本发明公开了一种轴流风机叶片,所述轴流风机叶片为前弯式叶片,所述轴流风机叶片的尾缘具有锯齿状结构,叶片表面沿叶片长度方向设置有脊状结构,多个所述脊状结构沿叶片宽度方向间隔平行设置。本发明具有在低转速工况下降噪效果明显等优点。(The invention discloses an axial flow fan blade which is a forward-bent blade, the trailing edge of the axial flow fan blade is of a sawtooth structure, the surface of the blade is provided with ridge-shaped structures along the length direction of the blade, and a plurality of the ridge-shaped structures are arranged in parallel at intervals along the width direction of the blade. The invention has the advantages of obvious noise reduction effect under the working condition of low rotating speed and the like.)

1. An axial fan blade characterized in that: the axial flow fan blade is a forward-bent blade, the trailing edge of the axial flow fan blade is provided with a saw-toothed structure (1), the surface of the blade is provided with ridge-shaped structures (2) along the length direction of the blade, and the ridge-shaped structures (2) are arranged in parallel at intervals along the width direction of the blade.

2. The axial fan blade according to claim 1, wherein: the forward bending angle theta of the forward bending type blade is 6-12 degrees.

3. The axial fan blade according to claim 1, wherein; the depth h of the saw teeth of the saw-toothed structure (1) is 2 mm-10 mm, and the angle alpha of the saw teeth is 10-60 degrees.

4. The axial fan blade according to claim 3, wherein: the number of the ridge-shaped structures (2) is a, the number of the saw teeth of the sawtooth-shaped structures is b, and b is 2-7 a.

5. The axial fan blade according to claim 4, wherein: the ridge structure (2) is a groove-like structure.

6. The axial fan blade according to any one of claims 1 to 5, wherein: the thickness of the blade leading edge is the same as that of the blade trailing edge.

7. The utility model provides an axial fan which characterized in that: comprising an axial fan blade according to any of claims 1 to 5.

8. The axial flow fan according to claim 7, wherein: the axial flow fan is a low-rotating-speed variable frequency motor, and the maximum rotating speed of the fan is less than 1450 r/min.

9. The axial flow fan according to claim 8, wherein: the axial flow fan further comprises a temperature sensor, and the temperature sensor is linked with the fan switch.

10. The axial flow fan according to claim 9, wherein: the axial flow fan is respectively provided with at least three air quantity rotating speeds with different gears, and the rotating speeds are recorded as n_min、n_mid、n_maxSatisfy n_min＜n_mid＜n_maxWhen the temperature sensor detects that the indoor temperature is T₁When the rotating speed of the fan is automatically turned on to be n_minWhen the indoor temperature is T₂When the fan rotates, the rotating speed of the fan is automatically switched to n_midWhen the indoor temperature reaches T₃At temperature, the rotation speed is automatically switched to n_maxWherein T is₁＜T₂＜T₃。

Technical Field

The invention relates to the technical field of fan noise reduction and environmental protection, in particular to an axial flow fan blade and a fan.

Background

Along with the increase of the urban electricity utilization scale, the construction positions of electric power facilities such as transformer substations and energy storage stations are closer to the urban human environment. At present, urban power facilities are mainly arranged indoors, the influence of noise of main power equipment such as transformers and reactors on the surrounding environment can be effectively isolated, and meanwhile, a new noise problem can be brought. The main equipment has large heat productivity, so that a large number of ventilation and heat dissipation devices need to be arranged on the outer wall and the roof of an indoor electric facility, the devices can generate large noise and even cause the problem of standard exceeding of factory noise, and in recent years, the noise of the heat dissipation devices causes frequent disputes of complaints of residents. The ventilation and heat dissipation of indoor electric facilities mainly adopt wall fans and roof fans, and most of the fans are axial fans. Research shows that the source of the axial flow fan noise mainly has the following four aspects: firstly, electromagnetic noise generated when the motor operates; mechanical noise generated by rotation of a rotating part of the fan; pneumatic noise generated by air flowing in the fan air duct; and fourthly, the vibration of the fan is transmitted to the radiator or the transformer body through the structure to cause the low-frequency noise caused by the structure vibration transmission.

The mechanical component noise of the fan can be realized by selecting a type low-noise motor, a bearing and optimizing the balance of a rotating component, and the mechanical noise of the fan can be effectively reduced by fine dynamic balance before the fan is installed. The vibration reduction of the fan body can adopt a proper vibration reduction structure such as a rubber ring, a vibration isolation support and the like to effectively isolate the vibration transmission between the fan body and a mounting base or a wall surface.

Firstly, the fan blade impacts airflow at high speed when rotating, a turbulent flow field is generated around the fan blade, and the severely disturbed flow field generates noise; the other is that the air outlet of the fan has high-speed air turbulence to cause pneumatic noise of the air outlet. The blade turbulence noise reduction is mainly developed from the following directions:

one is to increase the number of blades. The fan flow can be increased at the same rotating speed by increasing the number of the blades, which means that the rotating speed required by the impeller with more blades is smaller under the same flow condition, and the mechanical noise of a rotating part of the fan is smaller when the rotating speed is smaller;

secondly, the surface roughness of the blade is changed. The surface roughness of the blade is changed through a proper material or process, so that the pulsating pressure caused by the inflow turbulence on the surface of the blade is attenuated to a certain extent under the buffer of a micro-gap structure, and the noise caused by the pressure pulsation on the surface of the blade is effectively reduced;

and thirdly, the structure of the blade is changed. Research shows that the unsmooth structure of the blade trailing edge can effectively reduce the size of trailing edge turbulent eddies, so that the effect of noise reduction of the blade trailing edge is achieved, and the noise reduction effect of the sawtooth-shaped trailing edge structure similar to bird wings is obvious.

Chinese patent publication No. CN 211573864U discloses an axial fan wind wheel and its blades, which adopts wavy leading edge blades and the overall thickness of the blade body is gradually reduced from the leading edge to the trailing edge, and this kind of design can reduce the ventilation volume to a certain extent, and has a certain noise reduction effect at high rotational speed, but the noise reduction effect is not obvious at low rotational speed working condition, but the aerodynamic performance of partial blades is sacrificed.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the axial flow fan blade with obvious noise reduction effect under the working condition of low rotating speed.

In order to solve the technical problems, the invention adopts the following technical scheme:

the utility model provides an axial fan blade, axial fan blade is the antecurvature formula blade, axial fan blade's trailing edge has the sawtooth structure, and the blade surface is provided with ridge structure along blade length direction, and is a plurality of ridge structure is along blade width direction interval parallel arrangement.

As a further improvement to the above technical solution:

the forward bending angle theta of the forward bending type blade is 6-12 degrees.

The depth h of the saw teeth of the saw-toothed structure is 2 mm-10 mm, and the angle alpha of the saw teeth is 10-60 degrees.

The number of the ridge-shaped structures is a, the number of the saw teeth of the sawtooth-shaped structures is b, and b is 2-7 a.

The ridge structure is a trench-like structure.

The thickness of the blade leading edge is the same as that of the blade trailing edge.

As a general inventive concept, the present invention also provides an axial flow fan including the axial flow fan blade described above.

The axial flow fan is a low-rotating-speed variable frequency motor, and the maximum rotating speed of the fan is less than 1450 r/min.

The axial flow fan further comprises a temperature sensor, and the temperature sensor is linked with the fan switch.

The axial flow fan is respectively provided with at least three air quantity rotating speeds with different gears, and the rotating speeds are recorded as n_min、n_mid、n_maxSatisfy n_min＜n_mid＜n_maxWhen the temperature sensor detects that the indoor temperature is T₁When the rotating speed of the fan is automatically turned on to be n_minWhen the indoor temperature is T₂When the fan rotates, the rotating speed of the fan is automatically switched to n_midWhen the indoor temperature reaches T₃At temperature, the rotation speed is automatically switched to n_maxWherein T is₁＜T₂＜T₃。

Compared with the prior art, the invention has the advantages that:

the axial flow fan blade is a forward-bent blade, which is beneficial to stabilizing the leakage vortex at the blade top, so that a sound source generated by the leakage vortex tends to be stable, the noise reduction effect is obvious under the working condition of low rotating speed when the forward-bent angle theta is within the range of 6-12 degrees, and can reach 5dB (A) to the maximum, and the forward-bent blade can realize that the width of the blade from the inner diameter to the outer diameter is gradually increased, so that the ventilation volume is increased. The sawtooth structure of the tail edge can effectively reduce vortex shedding noise, and the aerodynamic noise reduction effect is obvious and can reach 10dB (A) to the maximum. The unsmooth ridge structure on the surface of the blade has the functions of reducing resistance and noise, can improve the radial pressure distribution of the blade, can absorb and buffer the pressure fluctuation on the wall surface of the blade, and reduces the broadband noise. The fan has the advantages of low noise, energy conservation, environmental protection and the like, is suitable for ventilating and radiating roof fans and wall fans of transformer substations, has higher requirements on noise value control and has low requirements on wind pressure.

The axial flow fan has the advantages that because the fan of the transformer substation is generally independently installed on a wall surface or a roof, the requirement on air pressure is not high, the noise of the fan can be effectively reduced by adopting the low-rotating-speed variable frequency motor, and the opening time and the air volume during opening of the fan are further reduced by adopting a variable frequency design.

Drawings

FIG. 1 is a schematic view of the blade forward curve definition of the present invention.

FIG. 2 is a two-dimensional schematic representation of the surface structure of a blade of the present invention.

The reference numerals in the figures denote: 1. a saw-toothed structure; 2. a ridge structure.

Detailed Description

The invention will be described in further detail below with reference to the drawings and specific examples. Unless otherwise specified, the instruments or materials employed in the present invention are commercially available.

Example 1

As shown in fig. 1 and 2, an axial flow fan blade is a forward-bent blade, the trailing edge of the axial flow fan blade has a saw-toothed structure 1, the surface of the blade is provided with ridge-shaped structures 2 along the length direction of the blade, and the ridge-shaped structures 2 are arranged in parallel along the width direction of the blade at intervals.

In the present invention, the forward-curved blade means that the leading edge of the blade is curved forward, the gravity center line refers to the axial (front-back) gravity center line of the blade, and the forward-curved blade means that the blade is curved forward along the rotation direction.

The forward bending angle theta of the forward bending type blade is 6-12 degrees.

The depth h of the saw teeth of the saw-toothed structure 1 is 2 mm-10 mm, and the angle alpha of the saw teeth is 10-60 degrees. The depth h of the sawteeth is generally related to the shape and the size of the blades, the air volume of an axial flow fan suitable for a transformer substation is generally less than 20000, the diameter of the axial flow fan is less than 1m, and the value of the depth h of the sawteeth of the sawtooth-shaped structure 1 is the best noise reduction effect within the range.

The number of the ridge-shaped structures 2 is a, the number of the saw teeth of the sawtooth-shaped structures 1 is b, and b is 2-7 a. a. The ratio of b determines the sparsity of the trailing edge sawtooth structure 1, the relative quantity relationship between the ridge structure 2 and the sawteeth in the sawtooth structure influences the noise reduction effect, and the noise reduction effect in the ratio range is the best.

The ridge structure 2 is a trench-like structure.

The thickness of the leading edge of the blade is the same as the thickness of the trailing edge of the blade.

An axial fan includes axial fan blades.

The axial flow fan is a low-rotating-speed variable frequency motor, and the maximum rotating speed of the fan is less than 1450 r/min.

The axial flow fan also comprises a temperature sensor, and the temperature sensor is linked with the fan switch.

The axial flow fan is respectively provided with at least three air quantity rotating speeds with different gears, and the rotating speeds are recorded as n_min、n_mid、n_maxSatisfy n_min＜n_mid＜n_maxWhen the temperature sensor detects that the indoor temperature is T₁When the rotating speed of the fan is automatically turned on to be n_minWhen the indoor temperature is T₂When the fan rotates, the rotating speed of the fan is automatically switched to n_midWhen the indoor temperature reaches T₃At temperature, the rotation speed is automatically switched to n_maxWherein T is₁＜T₂＜T₃。

An air volume of this embodiment is 9000m³The maximum rotating speed of the axial flow fan prototype is 960r/min, three-gear speed change of 560r/min, 720r/min and 960r/min can be realized, and the fan control can realize temperature linkage. The radius of the fan blade is400mm。

In the present embodiment, as shown in fig. 1, the forward bend angle θ is 8.3 °. As shown in FIG. 2, the sawtooth angle alpha of the sawtooth-shaped structure at the tail edge of the blade is 30 degrees, the sawtooth depth h is 6mm, and the ratio of the number a of the ridge-shaped structures 2 on the surface to the number b of the sawtooth-shaped structures at the tail edge is 1:3, namely, one ridge-shaped structure 2 on the surface of the blade corresponds to three sawtooth-shaped structures b at the tail edge.

In the embodiment, the fan is started and linked with the temperature sensing, and the air volume can be adjusted along with the temperature change. The temperature of the fan reaches T in the room₁When the temperature is (40 ℃), the minimum air volume mode is automatically started for heat dissipation, and when the temperature reaches T₂When the temperature is (45 ℃), the air volume of the fan is automatically switched to the middle air volume, and when the temperature reaches T₃At the temperature of 50 ℃, the air volume is adjusted to the maximum air volume for heat dissipation. The specific temperature, air volume setting and gear setting depend on actual requirements, and the purpose is to reduce the starting time of the fan and the air volume during starting as much as possible.

In the embodiment, a fan prototype is subjected to noise test in a semi-anechoic chamber, according to the standard of GB/T2888-2008 fan and Roots blower noise measurement method, the noise test is performed at the position where the angle between an air outlet and an axis is 45 degrees and the distance is 1m, the noise value is only 64dB (A) at the maximum rotating speed of 960r/min, and compared with the noise value of a fan with the same air volume of a common blade (the common blade is not provided with a forward bend and a sawtooth), the noise reduction effect is obvious, and the noise reduction effect is 6 dB (A).

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present invention, or modify equivalent embodiments to equivalent variations, without departing from the scope of the invention, using the teachings disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.