A blade and an impeller having the same

Abstract

The present application relates to a kind of vane and impeller with the vane, vane includes vane body, the front end of the vane body is vane leading edge, rear end is vane trailing edge;The thickness of the vane body is gradually increased thick gradually decreasing from vane leading edge to vane trailing edge, and form a smooth vane body;The maximum camber position of the cross section of the vane body is located at 25%-75% of vane chord length.The vane of the present application can effectively save material and reduce noise by changing the maximum camber position of vane cross section and using front bending and rear sweep form.

Description

Technical Field

[0001] This invention relates to the structural composition of an axial flow fan, specifically to a blade and an impeller having the blade, belonging to the field of fan technology. Background Technology

[0002] Blade sweep technology originated from research on aircraft wings in the last century. The rational application of this technology to blades can achieve the goals of improving the overall performance of the machine, reducing noise, and expanding the stable operating range. This technology has been widely used in impellers in industrial fields such as aero engines, compressors, and water turbines, but its application in small axial flow fans has been less studied.

[0003] The existing blade sweeping technology used in small axial flow fans is determined by sweeping or bending the pressure surface and suction surface at a certain angle. After the blade body design is completed, in order to compensate for the loss of air volume and air pressure and to consider the strength issue, the blade width needs to be increased by 20%-40%, which wastes materials.

[0004] Therefore, in order to solve the above-mentioned technical problems, it is indeed necessary to provide an innovative blade and an impeller having the blade to overcome the defects in the prior art. Summary of the Invention

[0005] The primary objective of this invention is to provide a forward-bending, backward-sweeping blade formed by changing the position of the maximum curvature of the blade cross section, which can effectively save materials and reduce noise.

[0006] A second objective of the present invention is to provide an impeller having the aforementioned blades.

[0007] To achieve the aforementioned primary objective, the technical solution adopted by this invention is as follows: a blade, comprising a blade body, wherein the front end of the blade body is the leading edge and the rear end is the trailing edge; the thickness of the blade body gradually increases and then gradually decreases from the leading edge to the trailing edge, forming a blade body with a smooth surface; the maximum curvature of the blade body cross-section is located at 25%-75% of the blade chord length. By changing the location of the maximum curvature of the blade cross-section, material can be effectively saved and noise reduced.

[0008] The blade of the present invention is further configured such that: the blade body adopts a forward-curved structure, and the forward curvature ratio is not greater than 75%, that is, a≤75%b, where a is the distance between the position of the maximum curvature of the blade and the leading edge point of the blade in the chord length direction; b is the chord length of the blade. Increasing the forward curvature ratio of the blade can effectively reduce noise.

[0009] The blade of the present invention is further configured such that: the blade body adopts a swept-back structure with a swept-back ratio of not less than 25%, i.e., a≥25%b, where a is the distance between the position of the maximum curvature of the blade and the leading edge point of the blade in the chord length direction; b is the blade chord length, which can save materials.

[0010] The blade of the present invention is further configured such that the blade body is divided into 5 sections along its extension direction, and the position of the maximum curvature of each section is as follows: in section 1, a=25-40%b; in section 2, a=35-50%b; in section 3, a=40-60%b; in section 4, a=50-70%b; and in section 5, a=60-75%, so that the position of the maximum curvature of the section is appropriate.

[0011] The blade of the present invention is further configured such that: section 1 and section 2 are forward-curved structures; and section 4 and section 5 are swept-back structures.

[0012] The blade of the present invention is further configured such that: the cross section 1 is located at the top of the blade body, the cross section 5 is located at the root of the blade body; and the cross section 3 is the dividing section of the blade cross section.

[0013] The blade of the present invention is further configured such that the cross sections are smoothly transitioned by circular arcs, making the blade surface smooth.

[0014] To achieve the second objective mentioned above, the technical solution adopted by the present invention is as follows: an impeller, which includes a hub and a plurality of blades, wherein the tips of the blades are connected to the hub.

[0015] The impeller of the present invention is further configured such that the impeller has a diameter of 450 mm and the number of blades is 5.

[0016] The impeller of the present invention is further configured such that: the maximum curvature of section 1 is located at 42%b, the chord length b = 115mm, the hub ratio is 0.3, and the blade mounting angle of section 1 is 39°;

[0017] The maximum curvature of section 2 is located at 46%b, the chord length b=99mm, the hub ratio is 0.563, and the plate mounting angle of section 2 is 22.45°.

[0018] The maximum curvature of section 3 is located at 50%b, the chord length b=90mm, the hub ratio is 0.738, and the blade mounting angle of section 3 is 18.97°.

[0019] The maximum curvature of section 4 is located at 53%b, the chord length b = 85mm, the hub ratio is 0.878, and the blade mounting angle of section 4 is 17.49°.

[0020] The maximum curvature of section 5 is located at 62%b, the chord length b = 81mm, the hub ratio is 1, and the blade mounting angle of section 5 is 15.7°.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention changes the position of the maximum curvature of the blade cross section, which only requires conventional processing technology and does not require special widening, thus effectively saving materials and reducing noise.

[0023] 2. The blade tip of the present invention adopts a forward-curved design, which will suppress the dispersion of the vortex core at the blade tip, reduce the vortex entrainment capacity, thereby reducing the interference of the low-speed flow at the blade root on the mainstream flow in the channel, reducing the flow loss at the blade tip, and improving the efficiency of the fan.

[0024] 3. The blade root section of the present invention adopts a swept-back design, which improves the flow near the trailing edge of the blade root, suppresses the formation of low-speed zones, avoids the occurrence of axial negative value zones, and thus improves the aerodynamic performance of the impeller. Attached Figure Description

[0025] Figure 1 This is a perspective view of the blade of the present invention.

[0026] Figure 2 This is a front view of the blade of the present invention and a schematic diagram of the positions of each cross section.

[0027] Figures 3 to 7 yes Figure 2 Cross-sectional view of section 1-5.

[0028] Figure 8 This is a comparison chart of the aerodynamic performance of the blades of this invention and conventional blades.

[0029] Figure 9 This is a comparison chart of the efficiency of the blades of this invention and conventional blades.

[0030] Figure 10 This is a schematic diagram of the impeller structure of the present invention.

[0031] Figure 11 This is a comparison diagram of the turbulent kinetic energy at the blade tip gap between the impeller of the present invention and a conventional impeller. Detailed Implementation

[0032] Please refer to the instruction manual appendix. Figure 1 To be continued Figure 7 As shown, this is a blade according to the present invention, which includes a blade body A. The front end of the blade body A is the leading edge B, and the rear end is the trailing edge C. The thickness of the blade body A gradually increases and then gradually decreases from the leading edge B to the trailing edge C, forming a smooth blade body A. According to Bernoulli's principle, the airflow of this blade is in a diffuser state, the airflow speed decreases, and the pressure loss decreases.

[0033] The most significant improvement of this invention lies in the fact that the maximum curvature of the blade body A is located at 25%-75% of the blade chord length. In existing blade designs, after the blade body is designed, the width increases by at least 10% due to performance and strength considerations, resulting in material waste. This invention, by changing the location of the maximum curvature of the cross-section, only requires meeting conventional processing standards, eliminating the need for additional widening and thus saving materials.

[0034] In this embodiment, the blade body A adopts a forward-curved structure. This forward-curved structure suppresses the dispersion of vortex nuclei at the blade tip, reducing the vortex's entrainment capacity, thereby reducing the interference of the low-velocity flow at the blade root with the mainstream flow in the channel, reducing flow losses at the blade tip, and improving wind turbine efficiency. The aforementioned forward curvature ratio is no greater than 75%, i.e., a ≤ 75%b, where a is the distance between the location of the maximum blade curvature and the blade's leading edge point along the blade chord length; b is the blade chord length. To avoid excessive twisting of the blade after forming due to an excessively large forward curvature ratio, which would reduce strength at this stage, controlling the maximum forward curvature ratio to no more than 75% can effectively reduce noise.

[0035] The blade body A adopts a swept-back structure. This swept-back structure improves flow near the blade root trailing edge, suppresses the formation of low-speed regions, and avoids the occurrence of axial negative value regions, thereby improving the impeller's aerodynamic performance. The sweep ratio is not less than 25%, i.e., a ≥ 25%b. Since a small sweep ratio at the blade root would lead to increased blade thickness, the above-mentioned sweep ratio is used to avoid abrupt changes at the blade root caused by the sweep. Furthermore, the improvement at the blade root only significantly affects low-flow-rate operating conditions, thus saving materials while meeting the performance requirements of the axial flow fan.

[0036] Furthermore, the blade body A of this embodiment is divided into 5 sections along its extension direction (e.g., Figure 2 As shown in the figure, section 1 is located at the tip of the blade body, and it and section 2 should be a forward-curved structure; section 5 is located at the root of the blade body, and it and section 4 should be a backward-swept structure; section 3 is the dividing section of the blade cross-section. The sections 1-5 are smoothly transitioned by circular arcs to make the blade surface smooth.

[0037] The positions of the maximum curvature of each section are as follows: a=25-40%b in section 1, a=35-50%b in section 2, a=40-60%b in section 3, a=50-70%b in section 4, and a=60-75% in section 5, so that the positions of the maximum curvature of the sections are appropriate.

[0038] Please continue to refer to the instruction manual appendix. Figure 8 The diagram shows a comparison of the aerodynamic performance of the blades of this invention and conventional blades. (Attached) Figure 9This is a comparison chart of the efficiency of the blades of this invention and conventional blades. Through experimental data comparison, under the same air volume, the blades of this invention show a significant improvement in static pressure and efficiency compared to conventional blades, while also expanding the high-efficiency range.

[0039] Please refer to the instruction manual appendix. Figure 10 As shown, it is an impeller of the present invention having the above-mentioned blades. The impeller has a diameter of 450 mm and includes a hub D and a plurality of blades A. The tip of the blades A is connected to the hub 4.

[0040] In this embodiment, the number of blades A is 5. The blades are designed based on the power consumption, specific speed, hub ratio, and pressure coefficient. The airflow angle of attack and blade installation angle of each blade section are determined using the variable circulation design method. The blade A specifically adopts the following structure: the maximum curvature of section 1 is located at 42%b, the chord length b = 115mm, the hub ratio is 0.3, and the blade installation angle of section 1 is 39°.

[0041] The maximum curvature of section 2 is located at 46%b, the chord length b=99mm, the hub ratio is 0.563, and the plate mounting angle of section 2 is 22.45°.

[0042] The maximum curvature of section 3 is located at 50%b, the chord length b=90mm, the hub ratio is 0.738, and the blade mounting angle of section 3 is 18.97°.

[0043] The maximum curvature of section 4 is located at 53%b, the chord length b = 85mm, the hub ratio is 0.878, and the blade mounting angle of section 4 is 17.49°.

[0044] The maximum curvature of section 5 is located at 62%b, the chord length b = 81mm, the hub ratio is 1, and the blade mounting angle of section 5 is 15.7°.

[0045] Please refer to the instruction manual appendix. Figure 11 As shown in the figure, the comparison diagram of the turbulent kinetic energy at the blade tip clearance between the impeller of this embodiment and the conventional impeller (left image is the embodiment, right image is the conventional impeller) shows that the radial height of the turbulent vortex core in this embodiment decreases less, the vortex core dispersion range is significantly reduced, and the vortex entrainment capacity is enhanced. This helps to reduce the interference of the leakage flow on the mainstream in the channel, thereby reducing the flow loss at the blade tip. Therefore, the comparison of the turbulent vortex core in the figure shows that the turbulent kinetic energy of this embodiment is smaller, resulting in lower noise.

[0046] The above-described specific embodiments are merely preferred embodiments of this invention and are not intended to limit this invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. An impeller, characterized in that: The device includes a hub and several blades, with the blade root connected to the hub. Each blade includes a blade body, with the leading edge at the front end and the trailing edge at the rear end. The thickness of the blade body gradually increases and then decreases from the leading edge to the trailing edge, forming a smooth blade body. The maximum curvature of the blade body's cross-section is located at 25%-75% of the blade chord length. The blade body adopts a forward-curved and backward-swept structure; the blade body is divided into 5 sections along its extension direction, among which, The maximum curvature of section 1 is located at 42%b, i.e., a=42%b, chord length b=115mm, hub ratio: 0.3, and blade mounting angle of section 1: 39°. The maximum curvature of section 2 is located at 46%b, i.e., a=46%b, chord length b=99mm, hub ratio: 0.563, and blade mounting angle of section 2: 22.45°. The maximum curvature of section 3 is located at 50%b, i.e., a=50%b, chord length b=90mm, hub ratio: 0.738, and blade mounting angle of section 3: 18.97°. The maximum curvature of section 4 is located at 53%b, i.e., a=53%b, chord length b=85mm, hub ratio: 0.878, and blade mounting angle of section 4: 17.49°. The maximum curvature of section 5 is located at 62%b, i.e., a=62%b, chord length b=81mm, hub ratio: 1, and blade mounting angle of section 5: 15.7°. Where a is the distance between the position of maximum blade curvature and the leading edge of the blade along the blade chord length; b is the blade chord length; Sections 4 and 5 are forward-bending structures; sections 1 and 2 are backward-sweeping structures.

2. The impeller as described in claim 1, characterized in that: Section 1 is located at the root of the blade body, and section 5 is located at the tip of the blade body; section 3 is the dividing section of the blade cross section.

3. The impeller as described in claim 1, characterized in that: The cross sections are smoothly transitioned by circular arcs.

4. The impeller as described in claim 1, characterized in that: The impeller has a diameter of 450 mm and 5 blades.

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