Special-shaped curve air duct structure for axial flow fan

Abstract

The special-shaped curve air duct structure comprises an inlet contraction section, a throat steady flow section and an outlet diffusion section which are used for the axial flow fan, the inlet contraction section and the outlet diffusion section are in continuous smooth curve transition, and the diameter of the throat steady flow section is smaller than that of the inlet contraction section and that of the outlet diffusion section. A venturi tube imitating structure is formed; a gap between the inner wall of the air duct and the impeller is in nonlinear change in the axial direction, and the gap at the throat part is minimum; the special-shaped curve air duct structure for the axial flow fan is simple and reasonable in structure and ingenious in design, the contour curve of the air duct is optimized through the Venturi effect, the gap self-adaptive design and the modular manufacturing process are combined, the machining cost is reduced while the aerodynamic efficiency is improved, and experiments show that the special-shaped curve air duct structure for the axial flow fan is suitable for large-scale popularization and application. According to the design, the fan efficiency can be improved by more than 20%, the noise is reduced by 7dB (A), and the fan is suitable for the fields of industrial ventilation, air conditioning systems and the like.

Description

Technical Field

[0001] This utility model relates to the field of axial flow fan technology, specifically to an irregular curved air duct structure for axial flow fans. Background Technology

[0002] An axial flow fan is a ventilation device in which the airflow direction is parallel to the fan axis. Its working principle is to accelerate the gas by rotating blades, thereby achieving ventilation, dust removal, and cooling effects. Due to its simple structure, small size, large air volume, low noise, and high efficiency, this type of fan is widely used in factories, mines, tunnels, cooling towers, vehicles, ships and other places.

[0003] Conventional axial flow fan ducts typically employ a cylindrical design with a uniform diameter. While this facilitates manufacturing and simplifies impeller-duct clearance control, it suffers from the following drawbacks:

[0004] Efficiency loss: The airflow velocity distribution in cylindrical ducts is uneven, turbulence is easily generated in the inlet section, and kinetic energy is lost due to the sudden expansion structure in the outlet section.

[0005] Noise issues: Significant airflow separation and vortex phenomena result in high noise levels during operation;

[0006] High energy consumption: Traditional designs cannot effectively utilize fluid kinetic energy and require higher power motors to achieve the target air volume. Utility Model Content

[0007] The purpose of this invention is to provide a non-circular curved air duct structure for axial flow fans, so as to solve the efficiency loss problem of traditional cylindrical air ducts mentioned in the background art, while also taking into account the feasibility of processing.

[0008] To achieve the above objectives, this utility model provides the following technical solution: an irregular curved air duct structure for an axial flow fan, comprising an inlet constriction section, a throat flow stabilization section, and an outlet diffusion section for the axial flow fan; the inlet constriction section and the outlet diffusion section are connected by a continuous smooth curve transition, and the diameter of the throat flow stabilization section is smaller than the diameter of the inlet constriction section and the diameter of the outlet diffusion section, forming a Venturi-like tube structure.

[0009] Preferably, the gap between the inner wall of the air duct and the impeller varies non-linearly along the axial direction, with the smallest gap at the throat.

[0010] Preferably, the air duct is composed of at least three axially segmented sections connected by flanges.

[0011] Preferably, it also includes a flow stabilizing component; the flow stabilizing component is arranged within the flow stabilizing section of the throat.

[0012] Preferably, the flow stabilizing component includes flow stabilizing blocks and flow reducing grooves; a plurality of flow stabilizing blocks are fixed in a ring array on the inner wall of the throat flow stabilizing section; a plurality of flow reducing grooves are formed in a linear array on the flow stabilizing blocks.

[0013] Preferably, the current stabilizer has an arc-shaped structure.

[0014] Preferably, the flow reduction groove has a V-shaped structure, and the opening of the flow reduction groove faces outward.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] 1. This utility model features an inlet contraction section, a throat stabilization section, and an outlet diffusion section. The inlet contraction section uses a high-order polynomial curve or spline curve for smooth transition, with a contraction ratio (the ratio of inlet diameter to throat diameter) of 1.2 to 1.5, accelerating airflow and suppressing turbulence. The throat stabilization section consists of a short straight section or a slightly curved section with a length ≤ 10% of the impeller diameter, used to stabilize the velocity distribution. The outlet diffusion section is designed with a gradually expanding curve with a diffusion angle θ = 5° to 8°, reducing the velocity and recovering kinetic energy. Compared with existing technologies, this utility model has a simple and reasonable structure and ingenious design. It optimizes the duct profile curve through the Venturi effect, combined with gap adaptive design and modular manufacturing process, improving aerodynamic efficiency while reducing processing costs. Experiments show that this design can improve fan efficiency by more than 20% and reduce noise by 7 dB(A), making it suitable for industrial ventilation, air conditioning systems, and other fields.

[0017] 2. This utility model, by setting up a flow stabilizing component, can extend the flow path of the airflow through the set flow stabilizing block, so as to stabilize the flow velocity distribution again, reduce the flow velocity, and recover kinetic energy. Through the set flow reduction groove, the contact area between the airflow and the flow stabilizing block can be increased, so as to further stabilize the flow velocity distribution, reduce the flow velocity, and recover kinetic energy. By stabilizing and reducing the flow velocity multiple times, the kinetic energy loss, noise during operation, and energy consumption are greatly reduced, thereby improving the practicality of this utility model. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 This is a cross-sectional view of the overall structure of this utility model;

[0020] Figure 3 This is a partial structural cross-sectional view of the present invention;

[0021] Figure 4 This is a schematic diagram of the current stabilizing component of this utility model.

[0022] In the picture:

[0023] 1. Inlet contraction section; 2. Throat flow stabilization section; 3. Outlet diffusion section; 4. Flow stabilization component; 401. Flow stabilization block; 402. Flow reduction channel. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] Please see Figures 1 to 4 This utility model provides a technical solution: a non-circular curved duct structure for an axial flow fan, including an inlet constriction section 1, a throat stabilization section 2, and an outlet diffuser section 3 for the axial flow fan; the contour curve of the inlet constriction section satisfies the equation y=ax3+bx2+cx+dy=ax3+bx2+cx+d, where a, b, c, and d are coefficients optimized according to air volume requirements; the inlet constriction section 1 and the outlet diffuser section 3 adopt a continuous smooth curve transition, and the diameter of the throat stabilization section 2 is smaller than the diameter of the inlet constriction section 1 and the diameter of the outlet diffuser section 3, forming a Venturi-like tube structure; the gap between the inner wall of the duct and the impeller changes non-linearly along the axial direction, with the smallest gap at the throat; the duct is composed of at least three axial segments connected by flanges; the gap between the inner wall of the duct and the impeller tip changes non-linearly along the axial direction, with the smallest gap at the throat (0.5%~1% of the impeller diameter), and the gap between the inlet / outlet sections gradually increases, taking into account both air tightness and processing tolerance.

[0026] This invention features an inlet contraction section 1, a throat stabilization section 2, and an outlet diffusion section 3. The inlet contraction section 1 uses a high-order polynomial curve or spline curve for smooth transition, with a contraction ratio (the ratio of inlet diameter to throat diameter) of 1.2 to 1.5, accelerating airflow and suppressing turbulence. The throat stabilization section 2 is a short straight section or a slightly curved section with a length ≤ 10% of the impeller diameter, used to stabilize the velocity distribution. The outlet diffusion section 3 is designed with a gradually expanding curve with a diffusion angle θ = 5° to 8°, reducing the velocity and recovering kinetic energy. Compared with existing technologies, this invention has a simple and reasonable structure and ingenious design. It optimizes the duct profile curve through the Venturi effect, combined with gap adaptive design and modular manufacturing process, improving aerodynamic efficiency while reducing processing costs. Experiments show that this design can improve fan efficiency by more than 20% and reduce noise by 7 dB(A), making it suitable for industrial ventilation, air conditioning systems, and other fields.

[0027] The total length of the air duct is L = 1.2m, the inlet diameter is D1 = 800mm, and the throat diameter is D2 = 600mm (contraction ratio 1.33).

[0028] The inlet contraction section is fitted with a cubic spline curve, and the diffusion section is designed with θ = 6°.

[0029] The impeller diameter is 595mm, the throat clearance is 2.5mm, and the inlet / outlet clearance gradually increases to 5mm;

[0030] The measured total pressure efficiency increased from 72% to 89%, and the noise decreased from 85dB(A) to 78dB(A).

[0031] As a preferred embodiment, it also includes a flow stabilizing component 4; the flow stabilizing component 4 is arranged in the throat flow stabilizing section 2; the flow stabilizing component 4 includes a flow stabilizing block 401 and a flow reducing groove 402; three flow stabilizing blocks 401 are fixed in a ring array on the inner wall of the throat flow stabilizing section 2; five flow reducing grooves 402 are linearly arrayed on the flow stabilizing block 401; the flow stabilizing block 401 has an arc-shaped structure; the flow reducing groove 402 has a V-shaped structure, and the opening direction of the flow reducing groove 402 is set outward.

[0032] This invention, by setting up a flow stabilizing component 4, can extend the flow path of the airflow through the flow stabilizing block 401, so as to stabilize the flow velocity distribution again, reduce the flow velocity, and recover kinetic energy. The flow reduction groove 402 can increase the contact area between the airflow and the flow stabilizing block 401, so as to further stabilize the flow velocity distribution, reduce the flow velocity, and recover kinetic energy. By stabilizing and reducing the flow velocity multiple times, the kinetic energy loss, noise during operation, and energy consumption are greatly reduced, thereby improving the practicality of this invention.

[0033] Working principle: The inlet contraction section 1 adopts a high-order polynomial curve or spline curve for smooth transition, with a contraction ratio (the ratio of inlet diameter to throat diameter) of 1.2 to 1.5, which accelerates the airflow and suppresses turbulence; the throat stabilization section 2 is a short straight section or a micro-arc section with a length ≤ 10% of the impeller diameter, used to stabilize the velocity distribution; the outlet diffusion section 3 is designed according to a gradually expanding curve with a diffusion angle θ = 5° to 8°, which reduces the velocity and recovers kinetic energy. The flow stabilization block 401 can extend the flow path of the airflow to stabilize the velocity distribution again and reduce the velocity and recover kinetic energy. The flow reduction groove 402 can increase the contact area between the airflow and the flow stabilization block 401 to further stabilize the velocity distribution and reduce the velocity and recover kinetic energy.

[0034] The above is the entire working process of the device, and all contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0035] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A profiled curve air duct structure for an axial flow fan, characterized by, The application relates to an axial flow fan, which comprises an inlet contraction section (1), a throat steady flow section (2) and an outlet diffusion section (3); the inlet contraction section (1) and the outlet diffusion section (3) are connected through a continuous smooth curve, and the diameter of the throat steady flow section (2) is smaller than the diameters of the inlet contraction section (1) and the outlet diffusion section (3), forming a structure similar to a Venturi tube.

2. A profiled curve air duct structure for an axial flow fan according to claim 1, wherein The gap between the inner wall of the air duct and the impeller changes nonlinearly along the axial direction, and the gap is the smallest at the throat.

3. The profiled curve air duct structure for an axial flow fan according to claim 1, wherein The air duct is composed of at least three axial sections connected through flanges.

4. The profiled curve air duct structure for an axial flow fan according to claim 1, wherein The application further comprises a steady flow assembly (4), which is arranged in the throat steady flow section (2).

5. The profiled curve air duct structure for an axial flow fan according to claim 4, wherein The steady flow assembly (4) comprises steady flow blocks (401) and flow reduction grooves (402); a plurality of the steady flow blocks (401) are fixed on the inner wall of the throat steady flow section (2) in an annular array; a plurality of the flow reduction grooves (402) are arranged on the steady flow blocks (401) in a linear array.

6. The profiled curve air duct structure for an axial flow fan according to claim 5, wherein The steady flow blocks (401) are arc-shaped structures.

7. The profiled curve air duct structure for an axial flow fan according to claim 5, wherein The flow reduction grooves (402) are V-shaped structures, and the opening directions of the flow reduction grooves (402) are outward.

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