High-efficiency low-noise backward centrifugal wind wheel structure

Abstract

The utility model provides a kind of efficient low-noise rear centrifugal wind wheel structure, it is related to centrifugal wind wheel technical field, including wheel disc and wheel cover, be provided with several blades between wheel disc and wheel cover;Several blades are equidistantly arranged around the rotation center of centrifugal wind wheel;The center of wheel cover is formed with air inlet, and air outlet is formed between adjacent blades;Along the direction of blade height, the root of blade is connected with wheel disc, and the top of blade is connected with wheel cover;Wheel cover and wheel disc adopt Bezier curve to construct profile, wheel cover inlet section and axial direction form 13~23's air intake attack angle, and outlet section is designed to form 6~16's horizontal upwarp angle by rotating diffuser;Wheel disc inlet section and axial direction form 55~65's air intake attack angle.The utility model has the beneficial effect of achieving the purpose of reducing noise and improving air volume.

Description

Technical Field

[0001] This utility model relates to the field of centrifugal impeller technology, and in particular to a high-efficiency, low-noise backward centrifugal impeller structure. Background Technology

[0002] In today's ventilation and air conditioning field, centrifugal impellers, as key components, are widely used in various ventilation equipment and air conditioning systems. Their performance directly affects the operating efficiency of the entire system and the user experience. Traditional backward centrifugal impellers (222.5mm outer diameter / 11-blade structure) have gradually revealed many undeniable defects during long-term use, causing numerous problems in practical applications.

[0003] First, the wind turbine employs a horizontal impeller base plate design, which leads to severe airflow separation problems during actual operation. When airflow passes over the horizontal impeller base plate, its structural characteristics prevent it from providing smooth and continuous guidance, causing turbulent flow near the base plate. This turbulent airflow continuously separates from the main flow, forming numerous vortices and turbulence. The presence of these vortices and turbulence results in a significant loss of energy from the originally orderly airflow due to internal friction and collisions. This not only means the wind turbine needs to consume more electricity to maintain the same airflow and pressure, increasing operating costs, but also leads to a substantial decrease in the efficiency of the entire ventilation or air conditioning system, preventing it from fully realizing its potential performance.

[0004] Secondly, the excessive number of blades in the wind turbine cannot be ignored. Too many blades make the internal flow channels of the turbine abnormally narrow, severely impeding airflow. Due to the limited space, the mutual compression and friction between airflow particles intensify, leading to a significant increase in eddy current losses. The generation of eddies not only consumes a large amount of energy but also destabilizes the airflow, further affecting the turbine's performance. Moreover, the narrow flow channels easily lead to the accumulation of dust and debris, increasing the difficulty of cleaning and maintenance costs, and potentially affecting the turbine's lifespan.

[0005] Furthermore, the poor matching between the rotor's outer diameter and the blades has become a key bottleneck limiting efficiency improvements. Precise matching between the outer diameter and blade design is essential for the rotor to achieve optimal operating efficiency under various conditions. However, traditional backward-curved centrifugal rotors have significant shortcomings in this regard. The mismatched outer diameter and blade combination prevents the rotor from fully utilizing the energy of the airflow during operation, hindering further efficiency improvements. Even with increased energy input, it is difficult to achieve a corresponding increase in airflow and pressure, resulting in energy waste and performance limitations.

[0006] Finally, high-frequency noise is another significant drawback of this wind turbine. During operation, due to a combination of factors such as airflow separation, eddy current losses, and unreasonable structural design, the wind turbine generates noticeable high-frequency noise. This high-frequency noise not only severely interferes with the surrounding environment, affecting people's work and quality of life, but may also damage the hearing health of those exposed to this environment for extended periods. For locations with high noise control requirements, such as hospitals, schools, and offices, the presence of this high-frequency noise makes traditional backward centrifugal wind turbines unable to meet practical needs, limiting their application scope.

[0007] In summary, these shortcomings of traditional backward centrifugal fans seriously affect their application performance and development prospects in the field of ventilation and air conditioning, and there is an urgent need for a new technical solution to solve these problems. Utility Model Content

[0008] This invention overcomes the shortcomings of the prior art and provides a high-efficiency, low-noise backward centrifugal impeller structure, achieving the purpose of reducing noise and increasing air volume.

[0009] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution: A high-efficiency, low-noise backward centrifugal impeller structure includes a impeller disc and an impeller cover, with several blades arranged between the impeller disc and the impeller cover; the blades are equidistantly arranged around the rotation center of the centrifugal impeller; an air inlet is formed at the center of the impeller cover, and an air outlet is formed between adjacent blades; along the blade height direction, the blade root is connected to the impeller disc, and the blade tip is connected to the impeller cover.

[0010] The wheel cover and wheel disc adopt Bezier curves to construct their profiles. The inlet section of the wheel cover forms an intake angle of attack of 13°~23° with the axial direction, and the outlet section forms a horizontal upturn angle of 6°~16° through a rotary diffuser design. The inlet section of the wheel disc forms an intake angle of attack of 55°~65° with the axial direction, and the outlet section forms a horizontal downturn angle of 3°~13° through a rotary diffuser design. The rotary diffuser design makes the cross-sectional area of ​​the outlet flow channel increase along the flow direction, forming a decelerating and diffused flow field. The profile curvature of the wheel cover and wheel disc transitions continuously and smoothly.

[0011] Furthermore, the number of blades is 7, and they are evenly spaced.

[0012] Furthermore, the blade wrap angle is 55°~65°, the blade profile is generated by a Bezier curve, the leading edge of the blade maintains aerodynamic matching with the wheel inlet section, and the trailing edge forms a diffusion channel with the wheel cover outlet section.

[0013] Furthermore, the ratio of blade chord length to pitch is 0.35 to 0.45.

[0014] Furthermore, the ratio of the cross-sectional area of ​​the wheel cover to the wheel disk outlet is 1:1.2~1.5.

[0015] Compared with the prior art, the beneficial effects of this utility model are: In this invention, the wheel cover and wheel disc are constructed with Bezier curves, and the inlet and outlet sections are designed to decelerate and pressurize the outlet airflow, thereby improving static pressure efficiency. The chord length-to-pitch ratio can reduce airflow separation and optimize airflow distribution. The reasonable ratio of the outlet cross-sectional area of ​​the wheel cover and wheel disc forms a decelerating and diffused flow field, which improves overall efficiency and pressure recovery capability, and also reduces noise. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the present invention and, together with the embodiments of the present invention, are used to explain the present invention. They do not constitute a limitation thereof. In the drawings: Figure 1 It is a 3D diagram of a high-efficiency, low-noise backward centrifugal impeller structure; Figure 2 This is a side view of a high-efficiency, low-noise backward centrifugal impeller structure; Figure 3 This is a cross-sectional view of the middle section of a high-efficiency, low-noise backward centrifugal impeller structure.

[0017] In the diagram: 1. Wheel; 2. Wheel cover; 3. Blade; 4. Air inlet; 5. Air outlet. Detailed Implementation

[0018] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0019] like Figures 1 to 3 As shown, this utility model claims protection for a high-efficiency, low-noise backward centrifugal impeller structure, including a disc 1 and a cover 2, with a plurality of blades 3 disposed between the disc 1 and the cover 2; the plurality of blades 3 are equidistantly arranged around the rotation center of the centrifugal impeller; an air inlet 4 is formed at the center of the cover 2, and an air outlet 5 is formed between adjacent blades 3; along the blade height direction, the blade root of the blade 3 is connected to the disc 1, and the blade tip of the blade 3 is connected to the cover 2; The wheel cover 2 and the wheel disk 1 employ Bezier curves to construct their profiles. The inlet section of the wheel cover 2 forms an intake angle of attack of 13° to 23° with the axial direction, while the outlet section, through a rotary diffuser design, forms a horizontal upward angle of 6° to 16°, thereby decelerating and pressurizing the outlet airflow and improving static pressure efficiency. Similarly, the inlet section of the wheel disk 1 forms an intake angle of attack of 55° to 65° with the axial direction, while the outlet section, through a rotary diffuser design, forms a horizontal downward angle of 3° to 13°, thereby decelerating and pressurizing the outlet airflow and improving static pressure efficiency. The rotary diffuser design causes the cross-sectional area of ​​the outlet flow channel to increase along the flow direction, forming a decelerating and diffused flow field. The curvature of the profiles of the wheel cover 2 and the wheel disk 1 transitions smoothly and continuously.

[0020] In this embodiment, there are 7 blades 3, which are evenly spaced. The wrap angle of the blade 3 refers to the distance from the starting point of the profile to the center of the circle to the ending point of the profile. Since the larger the wrap angle, the smaller the surface load of the blade 3, in this embodiment, the wrap angle of the blade 3 is 55°~65°. The profile of the blade 3 is generated by a Bezier curve. The leading edge of the blade 3 maintains aerodynamic matching with the inlet section of the impeller 1, and the trailing edge forms a diffusion channel with the outlet section of the impeller cover 2. This design is conducive to the smooth work of the impeller, the small pressure gradient on the surface of the blade 3, the reduction of airflow vortex shedding, and the improvement of the impeller aerodynamic efficiency.

[0021] The ratio of blade chord length to pitch is 0.35~0.45. The ratio of the outlet cross-sectional area of ​​the wheel cover 2 to the wheel disk 1 is 1:1.2~1.5. By controlling the ratio of the outlet cross-sectional area of ​​the wheel cover 2 to the wheel disk 1, the outlet flow channel cross-sectional area increases along the flow direction, forming a decelerating and diffuser flow field. In this flow field, the airflow velocity gradually decreases and the pressure gradually increases, converting the kinetic energy of the airflow into pressure energy, improving the pressure recovery capability of the wind turbine, and thus improving the overall efficiency of the wind turbine.

[0022] Verification has shown that the high-efficiency, low-noise backward centrifugal impeller structure of this invention increases the static pressure efficiency of the fan from 18.66% to 22.08% (an increase of 3.42%); the air volume from 343.22 cmh to 453.91 cmh (an increase of 32%); and the noise level from 61 to 60.9 (a decrease of 0.1 dB).

[0023] In this invention, the profiles of the wheel cover 2 and the wheel disk 1 are constructed using Bezier curves. The design of the inlet and outlet sections decelerates and pressurizes the outlet airflow, thereby improving static pressure efficiency. The chord length-to-pitch ratio can reduce airflow separation and optimize airflow distribution. The reasonable ratio of the outlet cross-sectional area of ​​the wheel cover 2 and the wheel disk 1 forms a decelerating and diffused flow field, which improves overall efficiency and pressure recovery capability, and also reduces noise.

[0024] Finally, it should be noted that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-efficiency, low-noise backward centrifugal impeller structure, characterized in that: It includes a wheel (1) and a wheel cover (2), and several blades (3) are arranged between the wheel (1) and the wheel cover (2); the several blades (3) are arranged at equal intervals around the rotation center of the centrifugal fan; an air inlet (4) is formed in the center of the wheel cover (2), and an air outlet (5) is formed between adjacent blades (3); along the blade height direction, the blade root of the blade (3) is connected to the wheel (1), and the blade tip of the blade (3) is connected to the wheel cover (2); The wheel cover (2) and the wheel disk (1) adopt the Bezier curve to construct the profile. The inlet section of the wheel cover (2) forms an intake angle of 13°~23° with the axial direction, and the outlet section forms a horizontal upturn angle of 6°~16° through the rotary diffuser design. The inlet section of the wheel disk (1) forms an intake angle of 55°~65° with the axial direction, and the outlet section forms a horizontal downturn angle of 3°~13° through the rotary diffuser design. The rotary diffuser design makes the cross-sectional area of ​​the outlet flow channel increase along the flow direction, forming a deceleration and diffusion flow field. The profile curvature of the wheel cover (2) and the wheel disk (1) transitions smoothly and continuously.

2. The high-efficiency, low-noise backward centrifugal impeller structure according to claim 1, characterized in that: The number of blades (3) is 7, and they are evenly distributed.

3. The high-efficiency, low-noise backward centrifugal impeller structure according to claim 2, characterized in that: The blade (3) has a wrap angle of 55°~65°. The blade (3) profile is generated by a Bezier curve. The leading edge of the blade (3) maintains aerodynamic matching with the inlet section of the wheel disk (1), and the trailing edge forms a diffusion channel with the outlet section of the wheel cover (2).

4. The high-efficiency, low-noise backward centrifugal impeller structure according to claim 2, characterized in that: The ratio of the chord length to the pitch of the blade (3) is 0.35 to 0.

45.

5. The high-efficiency, low-noise backward centrifugal impeller structure according to claim 1, characterized in that: The ratio of the outlet cross-sectional area of ​​the wheel cover (2) to that of the wheel disc (1) is 1:1.2~1.5.

Images