Axial flow fan outlet airflow large-rotation-angle resistance reduction device and axial flow fan system
By designing a drag reduction device for the flow cone, flow cone and shunt ring on the axial flow fan, the problem of large angle deflection caused by the air hood of the fan outlet is solved, and the energy loss is reduced, the air volume is increased, and the vibration and noise are reduced. Effect.
Patent Information
- Application Number
- CN202421073119.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2025-02-07
- Estimated Expiration
- 2034-05-17
AI Technical Summary
The airflow outlet of the axial fan is deflected by the air hood, resulting in large-angle local resistance, reduced air volume, increased vibration and increased noise.
A large angle drag reduction device for the axial fan outlet air flow including a flow shield, a flow ring and a shunt ring is designed to guide the air flow through the flow channel and shunt channel, so that its flow is more stable and local resistance is reduced.
It effectively reduces the energy loss of the fan outlet air flow, increases the fan air volume, reduces fan vibration and noise, and extends the fan life.
Smart Images
Figure CN222436683U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of axial flow fans, in particular to a large-angle drag reduction device for airflow at an axial flow fan outlet and an axial flow fan system. Background Art
[0002] Axial flow fans are widely used in various ventilation systems due to their large air volume. However, axial flow fans arranged outdoors (such as roof fans, marine fans, etc., among which roof axial flow fans are mainly used for indoor ventilation of various buildings. According to different use occasions, there are special products in terms of explosion-proof, temperature-resistant, moisture-resistant, wear-resistant, fire-fighting, and corrosion-resistant, which are suitable for medium and low pressure and large flow sites) need to be equipped with hoods in some cases due to the requirements of rainproof performance (by using hoods to cover the outdoor axial flow fan outlet to prevent rain from entering the room). This makes the airflow at the axial flow fan outlet suddenly deflect at a large angle (i.e. a large angle, specifically an angle of 90° to 180°), resulting in local resistance at the fan outlet (when the fluid flows through various local obstacles, the liquid flow will suddenly deform and generate a force that hinders the movement of the fluid. This force is called local resistance, and the energy loss caused by this is called local loss) is much larger than that at the free outlet, and the ventilation volume is greatly reduced. Even if the power of the fan is increased, the effect of increasing the fan air volume is very limited.
[0003] Conventional axial flow fans with hoods such as Figure 1 As shown, the casing 01 of the axial flow fan is arranged on the top of the building, the bottom opening of the casing 01 is the fan inlet, a safety net 02 is arranged between the fan inlet and the vent on the top of the building, the top opening of the casing 01 is the fan outlet, the fan outlet is covered with a hood 03, the motor 04 of the axial flow fan is arranged in the casing 01 through a motor support plate 05, and the output end of the motor 04 is connected to an impeller 06. When in use, the impeller 06 is driven to rotate by the motor 04, so that the indoor air of the building is drawn from the fan inlet to the fan outlet through the hood 03 to the outdoors for ventilation.
[0004] However, conventional axial flow fans with hoods have the following technical problems when in use:
[0005] First, since a hood 03 is provided at the fan outlet, the direction of the outlet airflow changes drastically by about 180°. Due to inertia, the outlet airflow continuously impacts the inner wall of the hood 03, and the downward airflow in the hood 03 collides with the upward airflow at the fan outlet, and finally completes the speed redistribution. This process causes impact losses, consumes a large amount of energy of the outlet airflow, and causes a significant reduction in the fan air volume.
[0006] Second, near the top of the casing 01, the kinetic energy of the airflow due to the viscosity is not enough to overcome the pressure difference and friction resistance to move forward. Under the action of the front and rear pressure difference, the airflow in this area tends to move along the inner wall of the casing 01 in the opposite direction of the main airflow. The combined effect of the pressure difference and friction resistance causes this part of the airflow to swirl in this area continuously and violently. Due to the viscosity, the gas will consume the energy of the flow when it swirls, resulting in energy loss. In addition, during the operation of the fan, the fluid particles in the vortex are constantly carried away by the main airflow. At the same time, airflow from the mainstream area continues to flow into the vortex area. This process is bound to cause collision and friction losses, consuming the energy of the outlet airflow.
[0007] Third, due to the unreasonable aerodynamic layout of the fan outlet and hood, the local resistance at the fan outlet is very large, resulting in a small fan air volume. Even if the power of motor 04 is increased, the improvement effect is not obvious, which causes an increase in energy consumption.
[0008] Fourth, the airflow at the fan outlet continuously impacts the inner wall of the hood 03, causing the fan to vibrate more and the noise to increase, which not only reduces the life of the fan but also affects the surrounding environment.
[0009] It can be seen that how to reduce the energy loss of the airflow at the outlet of the axial flow fan with a hood so as to increase the air volume of the fan and reduce the vibration of the fan is a problem that needs to be solved urgently. Utility Model Content
[0010] The purpose of the utility model is to provide an axial flow fan outlet airflow large-angle drag reduction device and an axial flow fan system to solve the problems existing in the above-mentioned prior art, which can reduce the energy loss of the fan outlet airflow, increase the fan air volume, and at the same time, can reduce the fan vibration, reduce the fan noise, and extend the fan life.
[0011] To achieve the above purpose, the utility model provides the following solutions:
[0012] The utility model provides a large-angle drag reduction device for airflow at the outlet of an axial flow fan, comprising a guide cover, a guide ring and a diverter ring, the guide cover is used to be fixed in the hood of the axial flow fan and cover the upper part of the casing of the axial flow fan, the guide cover is a concave structure in the middle part, and the outer edge of the guide cover can fit with the inner wall of the hood, so that a guide channel is formed between the guide cover, the hood and the upper edge of the casing, and the guide channel is used for supplying airflow out of the mainstream area of the fan outlet; the guide ring is used to be fixed to the upper edge of the casing, and the outer wall of the guide ring can fit with the inner wall of the upper edge of the casing, the cross section of the guide ring is a streamlined shape with a round upper part and a pointed lower part, the diverter ring is used to be fixed above the guide ring, and the cross section of the diverter ring is an arc-shaped cross section, so that a diverter channel is formed between the diverter ring and the guide ring, and the diverter channel is used for supplying airflow out of the near-wall area of the fan outlet.
[0013] Preferably, the side of the air deflector is formed with an outward curvature.
[0014] Preferably, the outer edge of the air deflector can be fixed to the inner wall of the hood by welding.
[0015] Preferably, the arc top of the guide ring is arranged to protrude from the upper edge of the casing.
[0016] Preferably, the outer wall of the guide ring can be fixed to the inner wall of the upper edge of the casing by welding.
[0017] The utility model also provides an axial flow fan system, comprising an axial flow fan, a hood and the large-angle drag reduction device for airflow at the outlet of the axial flow fan.
[0018] Compared with the prior art, the utility model has achieved the following technical effects:
[0019] The utility model provides a large-angle drag reduction device for the outlet airflow of an axial flow fan, comprising a guide cover, a guide ring and a splitter ring. The guide cover is fixed in the hood of the axial flow fan, the guide cover is a concave structure in the middle, and the outer edge of the guide cover is in contact with the inner wall of the hood, so that a guide channel is formed between the guide cover, the hood and the upper edge of the casing. During the operation of the fan, the airflow in the mainstream area of the fan outlet can pass through the guide channel, so that the change of the airflow direction of the fan outlet is smoother, the impact of the fan outlet airflow on the hood is reduced, the local resistance at the hood position is reduced, and at the same time, the collision of the airflow flowing downward through the hood and the upward airflow at the fan outlet is reduced, the energy loss of the fan outlet airflow is reduced, the fan air volume is increased, and the fan vibration caused by the fan outlet airflow impacting the hood is reduced.
[0020] By fixing the guide ring on the upper edge of the casing and fixing the diverter ring on the top of the guide ring, a diverter channel is formed between the diverter ring and the guide ring. During the operation of the fan, the airflow in the near-wall area of the fan outlet can pass through the diverter channel, that is, the guide ring with a streamlined cross-section cooperates with the diverter ring with an arc-shaped cross-section to guide the airflow in the near-wall area to pass through the diverter channel instead of making vortex motion in this area, thereby reducing the eddy current in the near-wall area, reducing local losses, and reducing the interaction between the airflow in the near-wall area and the airflow in the mainstream area, reducing the energy loss of the airflow at the fan outlet, and increasing the fan air volume.
[0021] The presence of the guide ring at the fan outlet can also increase the air flow velocity near the wall, making it greater than the air flow velocity in the middle position, thereby forming a pressure difference between the near wall and the middle position, pressing the air flow from the middle to the surroundings, and promoting the turning of the air flow at the outlet. This also reduces the energy loss of the fan outlet airflow and increases the fan air volume.
[0022] It can be seen that the large-angle drag reducing device for the axial flow fan outlet airflow provided by the utility model can reduce the energy loss of the fan outlet airflow and increase the fan air volume. At the same time, it can reduce the fan vibration, reduce the fan noise and extend the fan life. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0024] Figure 1 A schematic diagram of a conventional axial flow fan with a hood.
[0025] Figure 1 In the middle: 01- housing, 02- safety net, 03- hood, 04- motor, 05- motor support plate, 06- impeller.
[0026] Figure 2 A schematic diagram of an axial flow fan system provided by an embodiment of the utility model;
[0027] Figure 3 for Figure 2 The enlarged view of point A in the middle;
[0028] Figure 4 A schematic diagram of a guide ring provided in an embodiment of the utility model;
[0029] Figure 5 for Figure 4 Cross-sectional view of the middle BB;
[0030] Figure 6 A schematic diagram of a diverter ring provided in an embodiment of the utility model;
[0031] Figure 7 for Figure 6 Cross-sectional view of CC.
[0032] Figure 2-Figure 7 Middle: 1- guide cover, 2- guide ring, 3- diverter ring, 4- wind cap, 5- housing, 6- motor, 7- motor support plate, 8- impeller, 9- safety net. DETAILED DESCRIPTION
[0033] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0034] The utility model aims to provide an axial flow fan outlet airflow large-angle drag reduction device and an axial flow fan system to solve the problems existing in the prior art, which can reduce the energy loss of the fan outlet airflow, increase the fan air volume, and at the same time, can reduce the fan vibration, reduce the fan noise, and extend the fan life.
[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.
[0036] like Figure 2-Figure 7 As shown, this embodiment provides a large-angle drag reduction device for airflow at the outlet of an axial flow fan, comprising a guide cover 1, a guide ring 2 and a splitter ring 3. The guide cover 1 is used to be fixed in the hood 4 of the axial flow fan and cover the upper part of the casing 5 of the axial flow fan. The guide cover 1 is a concave structure in the middle, and the outer edge of the guide cover 1 can fit with the inner wall of the hood 4, so that a guide channel is formed between the guide cover 1 and the upper edge of the hood 4 and the casing 5. The guide channel is used to supply airflow out of the mainstream area of the fan outlet; specifically, in this embodiment, the outer edge of the guide cover 1 The edge is welded and fixed to the inner wall of the hood 4 to realize the installation of the guide cover 1. During the operation of the fan, the airflow in the mainstream area of the fan outlet can pass through the guide channel, so that the change of the direction of the airflow at the fan outlet is smoother, the impact of the airflow at the fan outlet on the hood 4 is reduced, and the local resistance at the position of the hood 4 is reduced. At the same time, the collision of the airflow flowing downward through the hood 4 and the upward airflow at the fan outlet is reduced, the energy loss of the airflow at the fan outlet is reduced, the fan air volume is increased, and the fan vibration caused by the airflow at the fan outlet impacting the hood 4 is reduced.
[0037] In this embodiment, the side of the air guide cover 1 is formed with an outward curvature, so that the airflow at the fan outlet flows more smoothly through the air guide channel.
[0038] In this embodiment, if Figure 3-Figure 5 As shown, the guide ring 2 is used to be fixed to the upper edge of the housing 5, and the outer wall of the guide ring 2 can fit with the inner wall of the upper edge of the housing 5. The cross section of the guide ring 2 is a streamlined shape with a round top and a pointed bottom. Figure 6-Figure 7 As shown, the diverter ring 3 is used to be fixed above the guide ring 2, and the cross-section of the diverter ring 3 is an arc-shaped cross-section, so that a diverter channel is formed between the diverter ring 3 and the guide ring 2, and the diverter channel is used for the outflow of airflow in the near-wall area of the fan outlet; specifically, in this embodiment, the outer wall of the guide ring 2 is welded and fixed to the inner wall of the upper edge of the casing 5 to achieve the installation of the guide ring 2, and the diverter ring 3 can be welded to the upper edge of the casing 5 through a plurality of support rods. During the operation of the fan, the airflow in the near-wall area of the fan outlet can pass through the diverter channel, that is, the guide ring 2 with a streamlined cross-section cooperates with the diverter ring 3 with an arc-shaped cross-section to guide the airflow in the near-wall area to pass through the diverter channel instead of making a vortex motion in this area, thereby reducing the eddy current in the near-wall area, reducing local losses, and reducing the interaction between the airflow in the near-wall area and the airflow in the mainstream area, reducing the energy loss of the airflow at the fan outlet, and increasing the air volume of the fan.
[0039] It should be noted that the presence of the guide ring 2 at the fan outlet can also increase the air flow velocity near the wall, making it greater than the air flow velocity at the middle position, thereby forming a pressure difference between the near wall and the middle position, pressing the air flow from the middle to the surroundings, and promoting the turning of the air flow at the outlet position, which also reduces the energy loss of the fan outlet airflow and increases the fan air volume.
[0040] In this embodiment, the arc top of the guide ring 2 is arranged to protrude from the upper edge of the housing 5, which further ensures the cooperation between the guide ring 2 and the diverter ring 3.
[0041] The present embodiment also provides an axial flow fan system, including an axial flow fan, a hood 4 and the above-mentioned axial flow fan outlet airflow large-angle drag reduction device; specifically, the axial flow fan in the present embodiment includes conventional components such as a casing 5, a motor 6, a motor support plate 7, an impeller 8 and a safety net 9. The hood 4 is arranged at the fan outlet. The difference from a conventional axial flow fan with a hood is that the above-mentioned axial flow fan outlet airflow large-angle drag reduction device is installed.
[0042] Compared with conventional axial flow fans with hoods, this device has the following advantages:
[0043] First, the design of the air deflector 1 and the wind hood 4 reduces the impact of the airflow on the wind hood 4, makes the change of the airflow direction smoother, reduces the local resistance at the position of the wind hood 4, reduces the energy loss of the airflow at the fan outlet, increases the air volume of the fan, reduces the vibration of the fan, reduces the noise of the fan, and extends the life of the fan.
[0044] Second, the design of the guide ring 2 and the diverter ring 3 reduces the vortex of the fan, makes the internal flow field of the fan smoother, reduces the local resistance at the fan outlet, and increases the air volume of the fan.
[0045] Third, the local resistance at the fan outlet is reduced by the drag reduction device, which means that to achieve the same air volume requirement, the fan requires a smaller motor power, and therefore, the fan consumes less energy.
[0046] The present invention uses specific examples to illustrate the principle and implementation of the present invention. The above examples are only used to help understand the method and core idea of the present invention. At the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.
Claims
1. A large-angle drag reduction device for airflow at the outlet of an axial flow fan, characterized in that: It includes a guide cover, a guide ring and a diverter ring. The guide cover is used to be fixed in the hood of an axial flow fan and cover the top of the casing of the axial flow fan. The guide cover is a concave structure in the middle, and the outer edge of the guide cover can fit with the inner wall of the hood to form a guide channel between the guide cover, the hood and the upper edge of the casing, and the guide channel is used to supply airflow out of the mainstream area of the fan outlet; the guide ring is used to be fixed to the upper edge of the casing, and the outer wall of the guide ring can fit with the inner wall of the upper edge of the casing, the cross-section of the guide ring is a streamlined shape with a round upper part and a pointed lower part, and the diverter ring is used to be fixed above the guide ring, and the cross-section of the diverter ring is an arc-shaped cross-section to form a diverter channel between the diverter ring and the guide ring, and the diverter channel is used to supply airflow out of the near-wall area of the fan outlet.
2. The large-angle drag reduction device for airflow at the outlet of an axial flow fan according to claim 1, characterized in that: The side of the air deflector is formed with an outward curvature.
3. The large-angle drag reduction device for airflow at the outlet of an axial flow fan according to claim 1, characterized in that: The outer edge of the air deflector can be welded and fixed to the inner wall of the hood.
4. The large-angle drag reduction device for airflow at the outlet of an axial flow fan according to claim 1, characterized in that: The arc top of the guide ring is arranged to protrude from the upper edge of the casing.
5. The large-angle drag reduction device for airflow at the outlet of an axial flow fan according to claim 1, characterized in that: The outer wall of the guide ring can be welded and fixed to the inner wall of the upper edge of the casing.
6. An axial flow fan system, characterized in that: The invention comprises an axial flow fan, a hood and a large-angle drag reduction device for airflow at an axial flow fan outlet as claimed in any one of claims 1 to 5.