Air guide hood, axial flow fan and air conditioning unit

Abstract

The present invention provides a deflector wind ring, an axial flow fan and an air conditioning unit, wherein the deflector wind ring defines an axial direction, and the two ends of the axial direction are respectively defined as an air intake port for gas to enter the deflector wind ring and an air outlet port for gas to flow out of the deflector wind ring, and the deflector includes an inlet section, a middle section and an outlet section in sequence from the air intake port to the air outlet along the axial direction, and the middle section is provided with guide holes penetrating the wall thickness. The deflector wind ring, axial flow fan and air conditioning unit of the present invention change the conventional design concept that the inner surface of the existing deflector wind ring is usually a smooth and non-porous inner wall, and open guide holes in the middle section of the deflector wind ring, which can achieve the purpose of optimizing the airflow channel and reducing the wind noise of the airflow.

Description

Technical Field

[0001] The present invention relates to the technical field of fans, and in particular to a guide cover wind ring, an axial flow fan and an air conditioning unit. Background Art

[0002] Taking the rail transit train air conditioning unit as an example, there is often a high requirement for the noise of the air conditioning unit. When the noise requirement for the air conditioning unit is high, the axial flow fan is the main noise source in the entire air conditioning system. It is necessary to reduce the noise generated by the axial flow fan as much as possible while meeting the heat dissipation of the air conditioning system.

[0003] In the existing axial flow fans, the main reason for the noise is that the air driven by the rotation of the fan blades cannot form a relatively uniform airflow, so the stirred airflow is prone to produce a large noise.

[0004] Therefore, how to effectively reduce the noise generated by the axial flow fan during operation has become an urgent problem to be solved. Summary of the invention

[0005] In view of this, the present invention proposes a guide cover wind ring, an axial flow fan and an air conditioning unit which can effectively reduce the noise generated when the axial flow fan is running.

[0006] In one aspect, the present invention provides a guide cover wind ring, which defines an axial direction, and the two ends of the axial direction are respectively defined as an air intake port for gas entering the guide cover wind ring and an air outlet port for gas flowing out of the guide cover wind ring, and the guide cover includes an inlet section, a middle section and an outlet section in sequence from the air intake port to the air outlet along the axial direction, and the middle section is provided with guide holes that penetrate the wall thickness.

[0007] In one embodiment, the middle section is evenly distributed along the circumferential direction to form a circle of guide holes, and the middle section is evenly distributed along the axial direction to form multiple circles of guide holes.

[0008] In one embodiment, the guide hole is a circular hole with a diameter of 3 to 8 mm.

[0009] In one embodiment, the middle section is in the shape of a cylinder with a constant diameter.

[0010] In one embodiment, the diameter of the inlet section gradually expands along the axial direction toward the air intake port.

[0011] On the other hand, the present invention provides an axial flow fan, comprising a deflector wind ring, fan blades and a motor as described above, wherein the fan blades are mounted on the motor and are coaxially arranged in the deflector wind ring along the axial direction.

[0012] In one embodiment, the fan blades include a rotating shaft and blades installed on the motor along the axial direction, a plurality of blades are evenly distributed around the rotating shaft, and each blade is provided with a reinforcing rib on a side facing the air inlet.

[0013] In one embodiment, the reinforcing ribs are arranged from the trailing edge of the blade to the leading edge of the blade and protrude from the surface of the blade, and a plurality of the reinforcing ribs are arranged at intervals on each blade.

[0014] In one embodiment, a tooth-shaped opening is provided on the trailing edge of each blade from the blade tip to the blade root, and the width and depth of the tooth-shaped opening increase or decrease with the increase or decrease of the width of the blade.

[0015] On the other hand, the present invention provides an air conditioning unit, including a condenser, the air conditioning unit further comprising the axial flow fan as described above, the axial flow fan being used as a condensing fan of the condenser.

[0016] The air deflector ring, axial flow fan and air-conditioning unit provided by the present invention have the following beneficial effects: the air deflector ring, axial flow fan and air-conditioning unit provided by the present invention change the conventional design concept that the inner surface of the existing air deflector ring is usually a smooth inner wall without holes, and an air deflection hole is opened on the middle section of the air deflector ring, so as to achieve the purpose of optimizing the air flow channel and reducing the wind noise of the air flow; the inlet section of the air deflector ring is designed as a bell mouth that gradually expands outward. Under the condition of ensuring the same air volume, the air deflector ring with the inlet section as the bell mouth can effectively reduce the wind speed through the bell mouth, thereby reducing the noise generated by the air flow; reinforcing ribs are added to the blades of the fan blades to enhance the strength and stability of the blades, thereby avoiding the noise generated by the resonance when the fan blades rotate; tooth-shaped openings are set on the blades of the fan blades, which effectively reduce the vortex flow loss at the blade outlet and improve the air flow performance of the fan blades, while reducing the rotation noise of the fan blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the three-dimensional structure of the air deflector wind ring of an embodiment of the present invention;

[0018] Figure 2 for Figure 1 A schematic diagram of the three-dimensional structure of the air deflector wind circle from another angle;

[0019] Figure 3 for Figure 1 A schematic diagram of the cross-sectional structure of the air deflector ring after being cut along the radial direction;

[0020] Figure 4 for Figure 3 A magnified view of part I;

[0021] Figure 5 is a schematic diagram of the three-dimensional structure of an axial flow fan according to an embodiment of the present invention;

[0022] Figure 6 for Figure 5 A schematic diagram of the three-dimensional structure of the fan blades in FIG.

[0023] Figure 7 The wind speed distribution diagram of the air intake of the straight-cylindrical air deflector wind ring;

[0024] Figure 8 This is the wind speed distribution diagram at the air intake of the air guide hood wind ring with a bell-shaped inlet section.

[0025] The components in the figure are labeled as follows:

[0026] The air deflector hood wind ring 10 (including the inlet section 11, the middle section 12, the outlet section 13, the air inlet 14, the air outlet 15; the air guide hole 121, the positioning notch 131);

[0027] Fan blade 20 (including rotating shaft 21, blade 22, reinforcing rib 221, tooth-shaped opening 222);

[0028] Motor 30;

[0029] Motor bracket 40;

[0030] Axial flow fan 100. DETAILED DESCRIPTION

[0031] Before describing the embodiments in detail, it should be understood that the present invention is not limited to the detailed structure or component arrangement described below or in the accompanying drawings in this application. The present invention may be an embodiment implemented in other ways. Moreover, it should be understood that the words and terms used herein are only used for descriptive purposes and should not be interpreted restrictively. The words "including", "comprising", "having" and the like used herein are intended to include the items listed thereafter, their equivalents and other additional items. In particular, when describing "a certain element", the present invention does not limit the number of the element to one, but may also include multiple elements.

[0032] As mentioned above, the main reason for the noise of axial flow fans is that the air driven by the rotation of the fan blades cannot form a relatively uniform airflow, so the stirred airflow easily emits a large operating aerodynamic noise. Through further research on the causes of axial flow fan noise, there are several aspects:

[0033] On the one hand, when the axial flow fan is running, the air usually flows from one side of the fan to the other side along the direction of the rotating axis of the axial flow fan. The concentrated flow of the air fluid causes a pressure difference on the two sides of the fan blade, which is specifically manifested as a pressure surface formed in the high-pressure area of ​​the blade and a suction surface formed in the low-pressure area of ​​the blade. Due to the gap between the blade and the wind ring of the guide cover, at the top of the blade, the air fluid is affected by the pressure difference and naturally flows from the pressure surface of the blade to the suction surface, thereby forming a blade tip leakage that causes noise. For axial flow fans, the air inlet and the middle section of the air guide ring contribute a large proportion to the sound pressure level, and the leakage vortex noise formed by the blade tip gap accounts for a non-negligible proportion, especially the broadband noise formed by the interaction of the blade tip gap between the blade and the air guide ring.

[0034] On the other hand, the resonance of the fan blades when they rotate is also one of the causes of noise.

[0035] Based on the above research results on the causes of axial flow fan noise, the present invention provides a guide cover wind ring, an axial flow fan and an air conditioning unit, which solve the noise problem of axial flow fan operation by solving the noise source.

[0036] See also Figure 1 , Figure 2 and Figure 3 The air deflector ring 10 of the embodiment of the present invention defines an axial direction, and is sequentially divided into an inlet section 11, a middle section 12, and an outlet section 13 along the axial direction. The front end of the inlet section 11 along the axial direction is an air intake port 14, and the rear end of the outlet section 13 along the axial direction is an air outlet 15. The gas enters the air deflector ring 10 from the air intake port 14, passes through the inlet section 11, the middle section 12, and the outlet section 13, and then flows out of the air deflector ring 10 from the air outlet 15.

[0037] More specifically, the inlet section 11 of the air deflector 10 is a bell mouth, that is, the diameter of the inlet section 11 gradually expands from the axial direction to the air inlet 14 to form an outward-expanding bell mouth. In a preferred embodiment, the outer diameter of the inlet section 11 expands by about 10% from the rear end to the front end, that is, the outer diameter of the front end of the inlet section 11 is about 110% of the outer diameter of the rear end of the inlet section 11.

[0038] In the illustrated embodiment, the diameter of the inlet section 11 expands from 562 mm to 617 mm.

[0039] See also Figure 7 and Figure 8 The wind speed distribution at the air inlet of the straight-cylindrical air guide ring and the air speed distribution at the air inlet of the air guide ring with a bell-shaped inlet section were tested. The wind speed distribution diagrams at the air inlet are shown as follows: Figure 7 and Figure 8 as shown in .

[0040] exist Figure 7 and Figure 8 In the air intake wind speed distribution diagram, the horizontal axis is Wherein, x is the distance from a certain point to the air inlet 14, d is the diameter of the air inlet 14, and the velocity of the isovelocity surface is expressed as a percentage of the air inlet flow velocity.

[0041] exist Figure 7 The flow rate percentage of the air intake of the straight-cylindrical air guide ring (circular air intake without a bell mouth) is calculated according to the following formula:

[0042]

[0043] exist Figure 8 In the calculation, the flow rate percentage of the air inlet of the guide cover wind ring with the inlet section being a bell mouth is calculated according to the following formula:

[0044]

[0045] In the above two formulas:

[0046] v0——average flow velocity at the air inlet, in m / s;

[0047] v x ——Suction flow rate at the control point, in m / s;

[0048] x——the distance from the control point to the air inlet, in m;

[0049] F——the area of ​​the air intake, in m 2 .

[0050] pass Figure 7 and Figure 8 It can be seen from the comparison that, under the condition of ensuring the same air volume, the wind ring of the air guide cover with a bell-shaped inlet section can effectively reduce the wind speed through the bell-shaped mouth, thereby reducing the noise generated by the air flow.

[0051] Please refer to Figure 4 , the middle section 12 of the air deflector wind ring 10 is a straight section, in the shape of a cylinder with equal diameter. The air deflector wind ring 10 is covered with guide holes 121 that penetrate the wall thickness. Specifically, the guide holes 121 are evenly distributed along the circumference of the middle section 12 to form a circle of guide holes 121, and multiple circles of guide holes 121 are evenly distributed in the axial direction of the middle section 12. In a preferred embodiment, the guide holes 12 are circular holes with an aperture of 3 to 8 mm. In the illustrated embodiment, in order to ensure the strength of the air deflector wind ring 10, the guide holes 12 are circular holes with an aperture of 3 mm.

[0052] Positioning notches 131 are provided at intervals on the outlet section 13 of the air deflector ring 10 for positioning and installing the air deflector ring 10 .

[0053] The above-mentioned air guide ring 10 has the front end of the bell mouth of the inlet section 11 as large as possible, and is evenly covered with 3mm diameter guide holes on the side wall of the middle section 12 connected to the bell mouth, so as to achieve the purpose of optimizing the air flow channel and reducing the wind noise of the air flow.

[0054] See also Figure 5 The axial flow fan 100 of the embodiment of the present invention includes a guide cover wind ring 10, a fan blade 20, a motor 30 and a motor bracket 40. The fan blade 20 is installed on the power output shaft of the motor 30 and is coaxially arranged in the guide cover wind ring 10. The motor bracket 40 extends outward from the motor 30 to fix the motor 30 and the fan blade 20 installed on the motor 30.

[0055] Please refer to Figure 6 The fan blade 20 includes a rotating shaft 21 and blades 22. The rotating shaft 21 is arranged along the axial direction and is installed on the power output shaft of the motor 30 arranged along the axial direction, so as to transmit the power output by the motor 30 to the fan blade 20; a plurality of blades 22 are evenly distributed around the rotating shaft 21, and rotate around the axial direction together with the rotating shaft 21 under the drive of the motor 30. When the fan blade 20 rotates under the drive of the motor 30, the blade 20 rotates around the axial direction to form an airflow. For each blade 20, the airflow flows into the blade channel from the leading edge of the blade and flows out from the trailing edge of the blade.

[0056] Each blade 22 is provided with a reinforcing rib 221, which is arranged on the side of the blade 22 facing the air inlet 14. More specifically, the reinforcing rib 221 is a convex rib protruding from the surface of the blade and arranged from the trailing edge of the blade to the leading edge of the blade. In the illustrated embodiment, four reinforcing ribs 221 are arranged at intervals on each blade. The reinforcing rib 221 can further enhance the strength and stability of the blade and reduce the noise generated by resonance when the fan blade 20 rotates.

[0057] The trailing edge of each blade 22 is provided with a tooth-shaped opening 222 along the direction from the blade top to the blade root, and the size (width and depth) of the tooth-shaped opening 222 varies with the width of the blade 22, that is, the tooth-shaped opening 222 at the wider width of the blade 22 closer to the blade top is wider and deeper, and the tooth-shaped opening 222 at the narrower width of the blade 22 closer to the blade root is narrower and shallower. The tooth-shaped opening 222 at the trailing edge of the blade can effectively reduce the vortex flow loss at the outlet of the blade 22, improve the air flow performance of the fan blade 22, and reduce the rotation noise of the fan blade 22.

[0058] The present invention also provides an air conditioning unit, including a refrigeration circuit formed by connecting a compressor, an evaporator, and a condenser through pipelines. The air conditioning unit uses the above-mentioned axial flow 100 as a condensing fan of the condenser.

[0059] In order to verify the noise reduction effect of the air deflector ring, axial flow fan and air conditioning unit of the present invention, three groups of schemes are used for comparison, wherein: Scheme 1 is a rail transit air conditioning unit using an existing axial flow fan; Scheme 2 is a rail transit air conditioning unit using an axial flow fan with an air deflector ring with a height of 97mm and air guide holes; Scheme 3 is a rail transit air conditioning unit using an air deflector ring with a height of 97mm and air guide holes and an axial flow fan with reinforced rib blades. The actual noise measurement results of the three groups of schemes at different monitoring points are shown in Table 1.

[0060] Table 1 Noise measurement values ​​of different schemes

[0061]

[0062] From the above monitoring results, we can see that: comparing Scheme 2 with Scheme 1, the noise values ​​of each monitoring point in Scheme 2 are lower than the noise values ​​of the corresponding monitoring points in Scheme 1; comparing Scheme 3 with Scheme 1, the noise values ​​of each monitoring point in Scheme 3 are lower than the noise values ​​of the corresponding monitoring points in Scheme 1; comparing Scheme 3 with Scheme 2, the noise values ​​of each monitoring point in Scheme 3 are lower than the noise values ​​of the corresponding monitoring points in Scheme 2. Therefore, it can be verified that by improving the air deflector wind ring 10 and the fan blades 20, the operating noise of the axial flow fan 100 can be reduced, thereby reducing the overall noise of the air conditioning unit using the axial flow fan 100.

[0063] Compared with the prior art, the air guide cover wind ring, axial flow fan and air conditioning unit of the present invention have at least the following advantages:

[0064] (1) In order to solve the leakage vortex noise caused by the tip gap of the blades, which accounts for a non-negligible proportion, and especially the broadband noise caused by the interaction between the tip gap between the blades and the air guide ring, the air guide ring, the axial flow fan and the air conditioning unit of the present invention change the conventional design concept that the inner surface of the existing air guide ring is usually a smooth and hole-free inner wall, and open a guide hole in the middle section of the air guide ring to achieve the purpose of optimizing the airflow path and reducing the wind noise of the airflow.

[0065] (2) In the air deflector ring, axial flow fan and air conditioner of the present invention, the inlet section of the air deflector ring is designed as a bell mouth that gradually expands outward. Under the condition of ensuring the same air volume, the air deflector ring with the inlet section as a bell mouth can effectively reduce the wind speed through the bell mouth, thereby reducing the noise generated by the air flow.

[0066] (3) In the air shroud, axial flow fan and air conditioner of the present invention, reinforcing ribs are added to the blades of the fan blades to enhance the strength and stability of the blades, thereby avoiding the noise generated by resonance when the fan blades rotate.

[0067] (4) In the hood, axial flow fan and air conditioner of the present invention, tooth-shaped openings are provided on the blades of the fan blades, which effectively reduce the vortex flow loss at the blade outlet, improve the air flow performance of the fan blades, and reduce the rotation noise of the fan blades.

[0068] To summarize, the air guide ring, axial flow fan and air conditioning unit of the present invention redesign the air guide ring of the axial flow fan to reduce the noise generated by the rapid passage of airflow when the fan is started, thereby reducing wind noise; and by setting ribs on the blades of the fan blades to strengthen them, the strength of the blades is further improved, thereby reducing the noise generated when the fan blades rotate; the design of the air guide ring and the fan blades reduces the noise generated when the axial flow fan is in operation, greatly reduces the noise generated by the air conditioning unit as a whole, improves the overall competitiveness of the air conditioning unit, and can meet more stringent requirements on noise.

[0069] The concepts described herein may be implemented in other forms without departing from their spirit and characteristics. The specific embodiments disclosed should be considered illustrative rather than restrictive. Therefore, the scope of the present invention is determined by the appended claims rather than by the preceding description. Any changes within the literal meaning and equivalent scope of the claims should fall within the scope of these claims.

Claims

1. An axial flow fan, characterized in that: It includes a shroud wind ring, a fan blade and a motor, wherein the shroud wind ring defines an axial direction, and the fan blade is mounted on the motor and coaxially arranged in the shroud wind ring along the axial direction; The two ends of the axis direction are respectively defined as an air inlet for gas to enter the air guide ring and an air outlet for gas to flow out of the air guide ring. The air guide ring includes an inlet section, a middle section and an outlet section in sequence from the air inlet to the air outlet along the axis direction. The middle section is provided with guide holes penetrating the wall thickness. The diameter of the inlet section gradually expands along the axial direction toward the air intake port, and the outer diameter of the front end of the inlet section is 110% of the outer diameter of the rear end of the inlet section; The middle section is in the shape of a cylinder with a constant diameter, and the middle section is evenly distributed along the circumference to form a circle of the guide holes, and the middle section is evenly distributed along the axis direction with multiple circles of the guide holes, and the guide holes are circular holes with a hole diameter of 3-8 mm; The outlet section is provided with positioning notches for positioning and installing the air guide ring of the air guide cover at intervals; The fan blades include a rotating shaft and blades installed on the motor along the axial direction, a plurality of the blades are evenly distributed around the rotating shaft, a reinforcing rib is provided on a side of each blade facing the air inlet, the reinforcing rib is provided from the trailing edge of the blade to the leading edge of the blade and protrudes from the surface of the blade, and a plurality of the reinforcing ribs are provided at intervals on each blade; A tooth-shaped opening is provided on the trailing edge of each blade from the blade top to the blade root, and the width and depth of the tooth-shaped opening increase or decrease with the increase or decrease of the width of the blade.

2. The axial flow fan according to claim 1, characterized in that: The diameter of the inlet section expands from 562 mm to 617 mm along the axial direction toward the air intake.

3. An air conditioning unit, comprising a condenser, characterized in that: The air conditioning unit further comprises an axial flow fan according to any one of claims 1 to 2, wherein the axial flow fan is used as a condensing fan of the condenser.

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