An impeller for a mixed or axial flow fan

Abstract

The impeller of the invention is characterized in that the leading edge comprises a leading edge inner section, a leading edge transition section and a leading edge outer section, and the trailing edge comprises a trailing edge inner section, a trailing edge transition section and a trailing edge outer section; from the inner radial side to the outer radial side, the distance between the leading edge side root and the blade tip is R1, and the distance between the trailing edge side root and the blade tip is R2; the leading edge transition section is located at (0.2-0.4) R1, and the trailing edge transition section is located at (0.5-0.6) R2; R1>R2; the radial section line of the leading edge transition section is bent in a straight line section, and the radial section line of the trailing edge transition section is bent in an arc line section; the above structure optimizes the inlet flow state of the leading edge and the trailing edge, and significantly improves the stability and redistribution of the pressure of the mixed flow fan.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery technology, specifically to an impeller, and more specifically to an impeller for a mixed-flow or oblique-flow fan. Background Technology

[0002] Uneven pressure distribution and poor pressurization often occur at the middle of the leading and trailing edges of the blades in mixed-flow or diagonal-flow fans, severely affecting the fan's performance. This problem is generally determined by the blade's geometry, rotational motion, and airflow characteristics. This pressure difference is crucial for the blades to generate lift and achieve ventilation. Specific factors include angle of attack and stagnation effect, blade bending and Bernoulli effect, blade rotation and secondary flow, and incoming flow conditions. Therefore, improving pressure distribution (especially reducing flow separation and vortices), reducing energy loss, and reducing aerodynamic noise to improve fan performance and efficiency are issues that those skilled in the art must constantly consider during impeller design. Based on this, optimizing the impeller design of mixed-flow or diagonal-flow fans, such as obtaining an improved impeller to enhance the pressurization effect at the leading and trailing edges of the blades, is particularly important.

[0003] The prior art CN101949392A discloses a high-efficiency mixed-flow compressor impeller, which includes a hub body 2a and a plurality of blades 2b combined with the hub body 2a. The blades 2b are mixed-flow blades, and a flow channel is formed between two adjacent blades 2b. The distance from the outer edge of the blade 2b to the center of the hub body 2a is greater than the radius of the hub body 2a, so that the outer edge of the blade 2b forms an auxiliary mixing section 2e. The hub body 2a has a central hole, through which the entire mixed-flow impeller is fixed to the rotor shaft 2c with a locking nut 2d. The mixed-flow blades 2b of the high-efficiency mixed-flow compressor impeller are mixed-flow blades, and the distance from their outer edge to the center of the hub body 2a is greater than the radius of the hub body 2a, so that the outer edge of the mixed-flow blades 2b forms an auxiliary mixing section 2e, which increases the mixing range of the impeller and significantly improves the efficiency by 4%. It is not only simple in structure and easy to implement, but also has a wide mixing range, good mixing effect, and high structural reliability.

[0004] The aforementioned prior art relates to the design and application of related mixed-flow compressor impellers. However, the above structure still has design limitations, and in the actual application of the impeller, there are still problems such as poor pressure boosting effect at the leading and trailing edges, uneven pressure distribution (with flow separation and vortices), energy loss, and aerodynamic noise. Therefore, in order to address these problems, the inventors propose an impeller for a mixed-flow or oblique-flow fan. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an impeller for a mixed-flow or oblique-flow fan.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An impeller for a mixed-flow or oblique-flow fan includes an upper cover plate, blades, a lower cover plate, a hub, and a motor. The motor is connected to the hub via a motor shaft, and the hub is connected to the lower cover plate. The blades are disposed between the upper and lower cover plates and include a leading edge, a trailing edge, a tip, and a root. The impeller is characterized in that: the leading edge includes an inner leading edge section, a leading edge turning section, and an outer leading edge section; the trailing edge includes an inner trailing edge section, a trailing edge turning section, and an outer trailing edge section; from the radially inner side to the radially outer side, the distance between the blade root and the blade tip on the leading edge side is R1, and the distance between the blade root and the blade tip on the trailing edge side is R2; the leading edge turning section is located at (0.2–0.4) R1, and the trailing edge turning section is located at (0.5–0.6) R2; an axially arranged capillary venturi-shaped flow channel structure exists between the leading edge turning section and the trailing edge turning section, and the venturi-shaped flow channel structure is located inside the blade.

[0008] Furthermore, the radial cross-sectional lines of the leading and trailing edge transition segments are either straight segments that bend or curved segments that bend.

[0009] Furthermore, the radial section line of the leading edge transition segment is a straight line segment that bends, while the radial section line of the trailing edge transition segment is an arc segment that bends.

[0010] Furthermore, the Venturi-shaped flow channel structure includes a tapering inlet flow channel located on the leading edge side, a widening outlet flow channel located on the trailing edge side, and a throat flow channel connecting the tapering inlet flow channel and the widening outlet flow channel.

[0011] Furthermore, the inlet of the gradually narrowing inlet channel is located on the leading edge bend section, and the outlet of the gradually widening outlet channel is located on the trailing edge bend section.

[0012] Furthermore, the Venturi-shaped flow channel structure consists of multiple parallel structures arranged along the axial direction.

[0013] Furthermore, the inlet cross-sectional area of ​​the gradually narrowing inlet channel is larger than the outlet cross-sectional area of ​​the gradually widening outlet channel.

[0014] Furthermore, R1 > R2.

[0015] Furthermore, the blade has a structure that gradually thins from the leading edge to the trailing edge.

[0016] Furthermore, the blades are curved and twisted and are forward-leaning.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The structural design of the leading and trailing edges of the blades has a very critical impact on blade pressurization and pressure distribution. The shape of the leading and trailing edges affects the direction and speed of airflow. A suitable leading and trailing edge design can better guide airflow, reduce energy loss of airflow at the leading and trailing edges, improve the conversion efficiency of airflow from kinetic energy to pressure energy, and thus enhance the stability and redistribution of pressure. For example, the leading edge includes an inner leading edge section, a leading edge turning section, and an outer leading edge section; the trailing edge includes an inner trailing edge section, a trailing edge turning section, and an outer trailing edge section. From the radially inner side to the radially outer side, the distance between the blade root and the blade tip on the leading edge side is R1, and the distance between the blade root and the blade tip on the trailing edge side is R2. The leading edge turning section is located at (0.2~0.4) R1, and the trailing edge turning section is located at (0.5~0.6) R2. R1>R2. The radial cross-sectional lines of the leading edge turning section and the trailing edge turning section are either straight segments with bends or curved segments with bends. The radial cross-sectional line of the leading edge turning section is a straight segment with bends, and the radial cross-sectional line of the trailing edge turning section is a curved segment with bends. The above structure optimizes the inlet flow pattern of the leading and trailing edges, and significantly improves the pressure stability and redistribution of the mixed-flow or mixed-flow fan.

[0019] 2. To reduce energy loss, particularly flow separation and vortices, this invention incorporates an axially arranged capillary-shaped Venturi flow channel structure between the leading-edge and trailing-edge transition points. This Venturi flow channel structure is located inside the blade and includes a converging inlet channel on the leading-edge side, a expanding outlet channel on the trailing-edge side, and a throat channel connecting the converging inlet and expanding outlet channels. The converging inlet channel inlet is located on the leading-edge transition section, and the expanding outlet channel outlet is located on the trailing-edge transition section. The Venturi flow channel structure consists of multiple parallel axially arranged channels, with the inlet cross-sectional area of ​​the converging inlet channel being larger than the outlet cross-sectional area of ​​the expanding outlet channel. This structure significantly improves the pressure at the trailing edge, reduces pressure pulsation, reduces excitation forces, minimizes flow separation and vortices, and effectively avoids energy loss.

[0020] 3. In order to reduce aerodynamic noise caused by the above-mentioned improved structure while pressurizing and redistributing pressure, the inventors further optimized the blade structure, such as the blade gradually thinning from the leading edge to the trailing edge, the blade being a twisted blade and a forward-tilted blade. The above structure effectively reduced noise and improved the conveying efficiency of the fan. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a cross-sectional view of the impeller structure of the present invention;

[0023] Figure 2 This is a front view of the blade structure of the present invention;

[0024] Figure 3 This is a structural view of a single blade of the present invention;

[0025] Figure 4 For the present invention Figure 3 Enlarged schematic diagram of the middle section structure.

[0026] The reference numerals in the above figures are as follows: 1. Upper cover plate; 2. Blade; 3. Lower cover plate; 4. Hub; 5. Motor; 6. Leading edge; 7. Trailing edge; 8. Blade tip; 9. Blade root; 10. Venturi-shaped flow channel structure; 101. Gradually narrowing inlet flow channel; 102. Throat flow channel; 103. Gradually widening outlet flow channel; 61. Inner section of leading edge; 62. Leading edge turning section; 63. Outer section of leading edge; 71. Inner section of trailing edge; 72. Trailing edge turning section; 73. Outer section of trailing edge; 74. Distance between the blade root and blade tip on the leading edge side; R1. Distance between the blade root and blade tip on the trailing edge side; R2. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The present invention will now be described in further detail with reference to the accompanying drawings.

[0029] like Figure 1-4 As shown, an impeller for a mixed-flow or oblique-flow fan includes an upper cover plate 1, blades 2, a lower cover plate 3, a hub 4, and a motor 5. The motor 5 is connected to the hub 4 via a motor shaft, and the hub 4 is connected to the lower cover plate 3. The blades 2 are disposed between the upper cover plate 1 and the lower cover plate 3, and each blade 2 includes a leading edge 6, a trailing edge 7, a blade tip 8, and a blade root 9. The leading edge 6 includes an inner leading edge section 61, a leading edge turning section 62, and a leading edge outer section 63; the trailing edge 7 includes an inner trailing edge section 71, a trailing edge turning section 72, and a trailing edge outer section 73; from the radially inner to the radially outer side, the distance between the blade root and the blade tip on the leading edge side is R1, and the distance between the blade root and the blade tip on the trailing edge side is R2. The leading edge turning section 62 is located at (0.2~0.4) R1, and the trailing edge turning section 72 is located at (0.5~0.6). At R2, there is an axially arranged capillary venturi-shaped flow channel structure 10 between the leading edge bend and the trailing edge bend, and the venturi-shaped flow channel structure 10 is located inside the blade 2.

[0030] Furthermore, the radial cross-sectional lines of the leading edge turning segment 62 and the trailing edge turning segment 72 are either straight segments bent or curved segments bent.

[0031] Furthermore, the radial section line of the leading edge turning segment 62 is a straight segment bent, and the radial section line of the trailing edge turning segment 72 is an arc segment bent.

[0032] Furthermore, the Venturi-shaped flow channel structure 10 includes a tapered inlet flow channel 101 located on the leading edge side, a tapered outlet flow channel 103 located on the trailing edge side, and a throat flow channel 102 connecting the tapered inlet flow channel 101 and the tapered outlet flow channel 103.

[0033] Furthermore, the inlet of the gradually narrowing inlet channel 101 is located on the leading edge turning section 62, and the outlet of the gradually widening outlet channel 103 is located on the trailing edge turning section 72.

[0034] Furthermore, the Venturi-shaped flow channel structure 10 has multiple parallel structures arranged along the axial direction.

[0035] Furthermore, the inlet cross-sectional area of ​​the gradually narrowing inlet channel 101 is larger than the outlet cross-sectional area of ​​the gradually widening outlet channel 103.

[0036] Furthermore, R1 > R2.

[0037] Furthermore, the blade 2 has a structure that gradually thins from the leading edge 6 to the trailing edge 7.

[0038] Furthermore, blade 2 is a twisted blade and a forward-tilted blade.

[0039] The structural design of the leading and trailing edges of the blades has a crucial impact on blade pressurization and pressure distribution. The shape of the leading and trailing edges affects the direction and speed of airflow. A suitable leading and trailing edge design can better guide airflow, reduce energy loss at the leading and trailing edges, improve the efficiency of airflow conversion from kinetic energy to pressure energy, and thus enhance pressure stability and redistribution. For example, the leading edge includes an inner leading edge section, a leading edge turning section, and an outer leading edge section; the trailing edge includes an inner trailing edge section, a trailing edge turning section, and an outer trailing edge section. From the radially inner side to the radially outer side, the distance between the blade root and the blade tip on the leading edge side is R1, and the distance between the blade root and the blade tip on the trailing edge side is R2. The leading edge turning section is located at (0.2~0.4) R1, and the trailing edge turning section is located at (0.5~0.6) R2. R1>R2. The radial cross-sectional lines of the leading edge turning section and the trailing edge turning section are either straight segments with bends or curved segments with bends. The radial cross-sectional line of the leading edge turning section is a straight segment with bends, and the radial cross-sectional line of the trailing edge turning section is a curved segment with bends. The above structure optimizes the inlet flow pattern of the leading and trailing edges, and significantly improves the pressure stability and redistribution of the mixed-flow or mixed-flow fan.

[0040] To reduce energy loss, particularly flow separation and vortices, this invention incorporates an axially arranged capillary Venturi-shaped flow channel structure between the leading and trailing edge bends. This Venturi-shaped flow channel structure is located inside the blade and includes a converging inlet channel on the leading edge, a expanding outlet channel on the trailing edge, and a throat channel connecting the converging inlet and expanding outlet channels. The converging inlet channel inlet is located on the leading edge bend, and the expanding outlet channel outlet is located on the trailing edge bend. The Venturi-shaped flow channel structure consists of multiple parallel structures arranged axially, with the inlet cross-sectional area of ​​the converging inlet channel being larger than the outlet cross-sectional area of ​​the expanding outlet channel. This structure significantly improves the pressure at the trailing edge, reduces pressure pulsation, reduces excitation forces, minimizes flow separation and vortices, and effectively avoids energy loss.

[0041] In addition to pressurization and pressure redistribution, in order to reduce aerodynamic noise caused by the above-mentioned improved structure, the inventors further optimized the blade structure, such as the blade gradually thinning from the leading edge to the trailing edge, the blade being a twisted blade and a forward-tilted blade. The above structure effectively reduced noise and improved the conveying efficiency of the fan.

[0042] The above embodiments are illustrative of the present invention and not intended to limit the invention. It is understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An impeller for a mixed-flow or oblique-flow fan, comprising an upper cover plate (1), blades (2), a lower cover plate (3), a hub (4), and a motor (5), wherein the motor (5) is connected to the hub (4) via a motor shaft, the hub (4) is connected to the lower cover plate (3), the blades (2) are disposed between the upper cover plate (1) and the lower cover plate (3), and the blades (2) include a leading edge (6), a trailing edge (7), a blade tip (8), and a blade root (9); characterized in that: The leading edge (6) includes the inner leading edge section (61), the leading edge turning section (62), and the outer leading edge section (63); the trailing edge (7) includes the inner trailing edge section (71), the trailing edge turning section (72), and the outer trailing edge section (73); from the radial inner side to the radial outer side, the distance between the leaf root and the leaf tip on the leading edge side is R1, and the distance between the leaf root and the leaf tip on the trailing edge side is R2. The leading edge turning section (62) is located at 0.2 to 0.4 times R1, and the trailing edge turning section (72) is located at 0.5 to 0.8 times R2; there is an axially arranged capillary Venturi-shaped flow channel structure (10) between the leading edge turning point and the trailing edge turning point, and the Venturi-shaped flow channel structure (10) is located inside the blade (2); the radial cross-section lines of the leading edge turning section (62) and the trailing edge turning section (72) are straight sections with bends or arc sections. The radial section of the leading edge turning section (62) is bent into a straight section, and the radial section of the trailing edge turning section (72) is bent into an arc section. The Venturi-shaped flow channel structure (10) includes a tapered inlet flow channel (101) located on the leading edge side, a tapered outlet flow channel (103) located on the trailing edge side, and a throat flow channel (102) connecting the tapered inlet flow channel (101) and the tapered outlet flow channel (103). The inlet of the tapered inlet flow channel (101) is located on the leading edge turning section (62), and the outlet of the tapered outlet flow channel (103) is located on the trailing edge turning section (72). The Venturi-shaped flow channel structure (10) has multiple parallel structures arranged along the axial direction. The inlet cross-sectional area of ​​the tapered inlet flow channel (101) is larger than the outlet cross-sectional area of ​​the tapered outlet flow channel (103). R1 ​​> R2.

2. The impeller of a mixed-flow or oblique-flow fan as described in claim 1, characterized in that, The blade (2) has a gradually thinning structure from the leading edge (6) to the trailing edge (7).

3. The impeller of a mixed-flow or oblique-flow fan as described in claim 1, characterized in that, The blade (2) is a curved and twisted blade and is a forward-tilted blade.

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