Impeller with noise reduction structure arranged in blade top area of blade and axial flow fan

Abstract

The invention discloses an impeller with noise reduction structures arranged in blade top areas and an axial flow fan. The impeller comprises a hub and blades, and the multiple blades are evenly arranged on the hub; a convex structure is arranged in a blade top area of a suction surface of the blade, the convex structure of the suction surface is in smooth transition with the suction surface, and the convex structure of the suction surface extends from a front edge area of the suction surface to a rear edge area of the suction surface; a convex structure is also arranged in the blade top area of the pressure face of the blade, the convex structure of the pressure face and the pressure face are in smooth transition, and the convex structure of the pressure face extends to the rear edge area of the pressure face from the front edge area of the pressure face. Vortex of the blade top gap is destroyed through the convex structure arranged in the blade top area, and blade tip noise is reduced on the premise that the performance of the fan is maintained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fan, and particularly relates to an impeller with a noise reduction structure arranged at a blade tip region and an axial flow fan. BACKGROUND

[0002] An axial flow fan is a device in which air flows parallel to the fan shaft, has the characteristics of simple structure and large flow, and is widely used in factories, buildings and other occasions. The axial flow fan has a noise problem, and the noise mainly comes from three aspects: 1. aerodynamic noise, which is generated by the interaction between the blade and the air, including airflow turbulence, vortex separation and other phenomena; 2. mechanical noise, which is mainly caused by the vibration and friction of the motor and bearing during operation, and the loosening of the coupling, the wear of the bearing or the imbalance of the impeller will cause the noise to increase; 3. resonance noise, which is caused by the coupling of the inherent frequency of the fan and the structural vibration, and is usually caused by design defects or improper installation. At present, mechanical noise and resonance noise can be reduced or eliminated through regular maintenance and calibration, but aerodynamic noise is difficult to solve. During the load operation of the fan, a large amount of vortex is generated in the gap between the blade and the collector, which increases the noise at the blade tip. The current solutions mainly include optimizing the blade design and optimizing the collector design, such as patent CN114458638A discloses a noise reduction structure for the barrel of an axial flow fan, which absorbs noise through a complex noise reduction unit to achieve noise reduction, patent CN105782090A discloses a noise reduction and vortex reduction axial flow fan, which optimizes the blade distribution angle and improves the collector structure to achieve noise reduction, and patent CN116006509A discloses a blade with noise reduction design at the blade tip gap of an axial flow fan, which provides a flow guide groove at the blade tip, and the flow guide groove penetrates from the suction surface to the pressure surface to achieve noise reduction. The existing solutions for reducing aerodynamic noise still have the problem of complex structure, and the improvement of the collector makes the collector structure more and more complex, while the optimization of the blade may affect other performances of the blade, which is difficult to balance. SUMMARY

[0003] To solve the above technical problems, the present application aims to provide an impeller with a noise reduction structure arranged at a blade tip region and an axial flow fan, which breaks the vortex at the blade tip gap through the convex structure arranged at the blade tip region, and reduces the noise at the blade tip under the premise of maintaining the performance of the fan.

[0004] To achieve the above-mentioned application purposes, the technical solutions adopted by the present application are as follows:

[0005] In the first aspect of the present application, an impeller with a noise reduction structure arranged at a blade tip region is provided, which comprises a hub and a blade, and a plurality of blades are uniformly arranged on the hub;

[0006] The tip region of the suction surface of the blade is provided with a convex structure, the convex structure of the suction surface is smoothly connected with the suction surface, and the convex structure of the suction surface extends from the leading edge region of the suction surface to the trailing edge region of the suction surface.

[0007] The tip region of the pressure surface of the blade is also provided with a convex structure, the convex structure of the pressure surface is smoothly connected with the pressure surface, and the convex structure of the pressure surface extends from the leading edge region of the pressure surface to the trailing edge region of the pressure surface.

[0008] Preferably, in the suction surface / pressure surface, the width / thickness of the convex structure is the smallest at the two ends and the largest in the middle, and the width and thickness of the convex structure gradually increase from the ends to the middle, and the ends of the convex structure are pointed ends.

[0009] More preferably, in the suction surface, one end of the convex structure is spaced apart from the leading edge edge on the same side, and the other end of the convex structure extends to the trailing edge edge on the same side.

[0010] More preferably, in the suction surface, the convex structure is spaced apart from the tip edge of the blade, and the gap between the convex structure and the tip edge gradually increases from the leading edge to the trailing edge.

[0011] More preferably, in the pressure surface, the convex structure extends from the leading edge edge to the trailing edge edge.

[0012] More preferably, in the pressure surface, the convex structure is spaced apart from the tip edge, and the gap between the convex structure and the tip edge gradually decreases from the leading edge to the trailing edge.

[0013] Preferably, the length of the tip chord of the blade is L, and the maximum protruding positions of the convex structures of the suction surface / pressure surface are both at 0.5L of the center of the tip chord.

[0014] More preferably, the sum of the maximum thicknesses of the convex structures on both sides of the blade accounts for one third of the maximum thickness at the center of the tip chord of the blade.

[0015] Preferably, the convex structure is formed based on the following three-dimensional outer contour function:

[0016] Z = -0.00957X 2 -0.34X-0.05475Y 2 -9.88Y-457.59;

[0017] The three-dimensional outer contour function is established in a rectangular coordinate system with the center of the hub as the origin.

[0018] In the second aspect of the present application, the present application provides an axial flow fan, comprising a collector and the above-mentioned impeller, and the impeller is arranged in the collector.

[0019] Advantages:

[0020] The convex structure arranged at the blade top region breaks the vortex of the blade gap, reduces the blade tip noise under the premise of maintaining the performance of the fan, and can reduce the blade tip noise of the impeller by 1-2dB compared with the fan without the convex structure. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Fig. 1 shows a schematic diagram of the axial flow fan of the present application;

[0022] Figure 2 Fig. 2 shows a schematic diagram of the impeller of the present application;

[0023] Figure 3 Fig. 3 shows a schematic diagram of the suction surface of the blade of the present application;

[0024] Figure 4 Fig. 4 shows a schematic diagram of the pressure surface of the blade of the present application;

[0025] Figure 5 Fig. 5 shows a schematic diagram of the existing impeller;

[0026] Figure 6 Fig. 6 shows a schematic diagram of the blade top chord length and the blade top chord center thickness of the existing impeller.

[0027] Fig. 1 shows a schematic diagram of the axial flow fan of the present application; DETAILED DESCRIPTION

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, specific embodiments of the present application will be described below with reference to the drawings. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0029] As Figures 1-4 shown, the present application proposes an impeller 1 with noise reduction structure arranged at the blade top region, which comprises a hub 11 and a blade 12, and a plurality of blades 12 are uniformly arranged on the hub 11.

[0030] The blade top region of the suction surface 121 of the blade 12 is provided with a convex structure 3, the convex structure 3 of the suction surface 121 is smoothly connected with the suction surface 121, and the convex structure 3 of the suction surface 121 extends from the leading edge 123 region of the suction surface 121 to the trailing edge 124 region of the suction surface 121.

[0031] A convex structure 3 is also provided in the blade tip area of ​​the pressure surface 122 of the blade 12. The convex structure 3 of the pressure surface 122 smoothly transitions to the pressure surface 122. The convex structure 3 of the pressure surface 122 extends from the leading edge 123 area of ​​the pressure surface 122 to the trailing edge 124 area of ​​the pressure surface 122.

[0032] like Figures 2-5 As shown, in the present invention, the convex structure 3 is integrally formed with the blade 12, which is easy to process. The arrangement of the convex structure 3 on the blade 12 causes the overall thickness of the blade 12 to present a unique variation trend, which is different from the design of thickening the leading edge 123 of the conventional blade 12, and is also different from the existing design of providing a guide groove for the blade tip. In the present invention, the convex structure 3 located in the suction surface 121 is in the shape of an elongated strip and is only located in the blade tip area. It has no effect on the rest of the suction surface 121, and the maximum air intake of the impeller 1 is not affected, with an error of approximately ±0.4%. Similarly, the convex structure 3 located in the pressure surface 122 is also in the shape of an elongated strip and has no effect on the air discharge of the impeller 1. The convex structure 3 arranged in the blade tip area of ​​the suction surface 121 and the pressure surface 122 serves to increase the wind resistance of the gap between the blade 12 and the collector 2, and has the effect of destroying the blade tip vortex, thereby reducing the blade tip noise.

[0033] In the present invention, the smooth transition between the convex structure 3 and the suction surface 121 / pressure surface 122 refers to a smooth transition at the connection between the convex structure 3 and the suction surface 121 / pressure surface 122 .

[0034] Furthermore, within the suction surface 121 / pressure surface 122, the convex structure 3 has the smallest width / thickness at its ends and the largest width / thickness in the middle. The width and thickness of the convex structure 3 gradually increase from the ends toward the middle, and the ends of the convex structure 3 are pointed. In other words, the convex structure 3 on the suction surface 121 has a shape with protruding and pointed ends and a large bulge in the middle, ensuring a good flow field at the blade tip of the suction surface 121.

[0035] Furthermore, within the suction surface 121, a gap exists between one end of the convex structure 3 and the leading edge 123 on the same side, while the other end of the convex structure 3 extends to the trailing edge 124 on the same side. Due to the gap between the convex structure 3 and the leading edge 123, air is cut by the leading edge 123 of the suction surface 121 of the blade 12 before encountering the convex structure 3, thereby increasing the wind resistance in the blade tip area on the suction surface 121. The absence of a gap between the convex structure 3 and the trailing edge 124, coupled with the overall streamlined design of the convex structure 3, prevents turbulent airflow between the convex structure 3 and the trailing edge 124, thereby reducing the negative impact of the convex structure 3 on the air intake and increasing the wind resistance in the blade tip area of ​​the suction surface 121.

[0036] Furthermore, within the suction surface 121, a gap exists between the convex structure 3 and the tip edge of the blade 12, and the gap between the convex structure 3 and the tip edge gradually increases from the leading edge 123 to the trailing edge 124. The convex structure 3 of the present invention does not completely cover the tip region of the suction surface 121. The placement of the convex structure 3 on the suction surface 121 increases the wind resistance of the suction surface 121 in the tip region while maintaining the maximum air intake, thereby reducing noise.

[0037] Furthermore, within pressure surface 122, convex structure 3 extends from leading edge 123 to trailing edge 124, meaning there is no gap between convex structure 3 and leading or trailing edges 123, 124. Pressure surface 122 directly bears the kinetic energy of the gas, and since there is no gap between convex structure 3 and leading edge 123, combined with the streamlined design of convex structure 3, the tip area of ​​pressure surface 122 increases wind resistance when it comes into contact with air, limiting the formation of vortices.

[0038] Furthermore, within the pressure surface 122 , there is a gap between the convex structure 3 and the blade tip edge, and the gap between the convex structure 3 and the blade tip edge gradually decreases from the leading edge 123 to the trailing edge 124 .

[0039] In the present invention, preferably, the blade tip chord length of the blade 12 is L, and the maximum protrusion position of the convex structure 3 of the suction surface 121 / pressure surface 122 is at the center of the blade tip chord, that is, 0.5L. Figure 6

[0040] In the present invention, preferably, the sum of the maximum thickness of the convex structures on both sides of the blade 12 accounts for one third of the maximum thickness of the blade tip chord center. Figure 6 As shown, the blade tip chord center thickness without the convex structure 3 is H. After adding the two convex structures 3, the maximum thickness of the blade tip chord center, that is, the maximum thickness of the blade tip chord center of the present invention, is 1.5H.

[0041] The convex structure 3 with the above characteristics of the present invention can achieve the effect of reducing noise without affecting the performance of the fan. Preferably, the convex structure 3 can be formed based on the following three-dimensional outer contour function: three-dimensional outer contour function Z = -0.00957X 2 -0.34X-0.05475Y 2 -9.88Y-457.59, the three-dimensional outer contour function is established in a rectangular coordinate system with the center of the hub 11 as the origin. X / Y / Z represent coordinate points respectively; the convex structure can delay the vortex diversion at the leading edge and weaken the vortex structure morphology at the trailing edge.

[0042] The axial flow fan formed based on the blade 12 structure of the present application maintains the performance without reduction, destroys the vortex between the blade 12 and the collector 2, and reduces the noise of the blade tip. Compared with the prior art, the present application can reduce the noise by 1-2 dB.

[0043] The above describes the embodiments provided by the present application in detail. The principles and implementation manners of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the core idea of the present application. It should be pointed out that, for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. An impeller with a noise reduction structure provided in the blade tip area, characterized in that: It comprises a hub (11) and blades (12), wherein a plurality of blades (12) are evenly arranged on the hub (11); A convex structure (3) is provided in the blade tip region of the suction surface (121) of the blade (12); the convex structure (3) of the suction surface (121) smoothly transitions with the suction surface (121); and the convex structure (3) of the suction surface (121) extends from the leading edge (123) region of the suction surface (121) to the trailing edge (124) region of the suction surface (121); A convex structure (3) is also provided in the blade tip region of the pressure surface (122) of the blade (12), and the convex structure (3) of the pressure surface (122) smoothly transitions with the pressure surface (122), and the convex structure (3) of the pressure surface (122) extends from the leading edge (123) region of the pressure surface (122) to the trailing edge (124) region of the pressure surface (122).

2. The impeller with a noise reduction structure provided in the blade tip area according to claim 1, characterized in that: In the suction surface (121) / pressure surface (122), the width / thickness of the two ends of the convex structure (3) is the smallest and the width / thickness in the middle is the largest, and the width and thickness of the convex structure (3) gradually increase from the end to the middle, and the end of the convex structure (3) is a pointed end.

3. The impeller with a noise reduction structure provided in the blade tip area according to claim 2, characterized in that: In the suction surface (121), there is a gap between one end of the convex structure (3) and the edge of the leading edge (123) on the same side, and the other end of the convex structure (3) extends to the edge of the trailing edge (124) on the same side.

4. The impeller with a noise reduction structure provided in the blade tip region according to claim 2 or 3, characterized in that: In the suction surface (121), there is a gap between the convex structure (3) and the blade top edge of the blade (12), and the gap between the convex structure (3) and the blade top edge gradually increases from the leading edge (123) to the trailing edge (124).

5. The impeller with a noise reduction structure provided at the blade tip region according to claim 2, characterized in that: In the pressure surface (122), the convex structure (3) extends from the edge of the leading edge (123) to the edge of the trailing edge (124).

6. The impeller with a noise reduction structure provided at the blade tip region according to claim 2 or 5, characterized in that: In the pressure surface (122), there is a gap between the convex structure (3) and the blade tip edge, and the gap between the convex structure (3) and the blade tip edge gradually decreases from the leading edge (123) to the trailing edge (124).

7. The impeller with a noise reduction structure provided at the blade tip region according to claim 2, characterized in that: The blade tip chord length of the blade (12) is L, and the maximum protrusion position of the convex structure (3) of the suction surface (121) / pressure surface (122) is located at 0.5L of the blade tip chord center.

8. The impeller with a noise reduction structure provided at the blade tip region according to claim 7, characterized in that: The sum of the maximum thicknesses of the convex structures (3) on both sides of the blade (12) accounts for one third of the maximum thickness of the blade tip chord center.

9. The impeller with a noise reduction structure provided at the blade tip region according to claim 1, characterized in that: The convex structure (3) is formed based on the following three-dimensional outer contour function: Z=-0.00957X 2 -0.34X-0.05475Y 2 -9.88Y-457.59; The three-dimensional outer contour function is established in a rectangular coordinate system with the center of the hub (11) as the origin.

10. An axial flow fan, comprising a collector (2), characterized in that: It also comprises the impeller (1) according to any one of claims 1 to 9, and the impeller (1) is arranged in the collector (2).

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