CN211525182U - Curved and swept blades and axial fans - Google Patents

Abstract

The utility model relates to a curved and swept blade and an axial flow fan. The curved and swept blade comprises a pressure surface and a suction surface opposite to the pressure surface. The starting point is the same, the forward bending angle of the swept blade is 7° to 11°, and the swept blade has a variable ring volume index ranging from -0.1 to -1. The pressure of the swept blade provided by the utility model increases along the height of the blade, forming a pressure gradient from the blade root to the blade tip, and has the shape of a wide blade tip and a narrow blade root. The twist of the blade is improved, the weight of the blade is reduced, and the manufacture of the blade is also facilitated. The blade tip of the swept blade has a high linear velocity, and the blade tip is used to reduce the loss of air volume and pressure, improve the aerodynamic efficiency, and thus enhance the working efficiency of the axial flow fan. The forward bending of the swept blade makes the force at the bend of the blade fully decomposed, so that the speed of the noise changes quickly, and the noise reduction effect is obvious.

Description

Curved and swept blades and axial fans

technical field

The utility model relates to the technical field of blades for condensing fans, in particular to curved and swept blades and axial flow fans.

Background technique

In the process of my country's development, the emergence of urban rail transit vehicles has a great impact on urban traffic and can improve the level of urban infrastructure construction. Among them, due to the special operation environment of rail transit vehicles and the special effects of public transportation, it is necessary to optimize the air conditioning performance of rail transit vehicles.

The key core component of the air conditioner of the rail transit vehicle - the condensing axial flow fan, is mainly responsible for the heat dissipation of the condenser. Once the fan fails, the temperature of the condenser will rise immediately, causing the compressor to stop under high pressure protection, making the air conditioner lose its cooling source and only have The role of ventilation. At the same time, the condensing axial fan is also the largest source of noise and vibration of the air conditioner. Therefore, improving the design level of the condensing axial fan so that it can meet the actual operation requirements of high reliability, light weight, low noise and low vibration has become the focus of rail air conditioning technology progress.

However, most of the condensing axial fans currently use arc veneer and airfoil veneer blades, resulting in high noise and low fan efficiency. As a result, the performance and efficiency of air conditioners for rail transit vehicles are still insufficient.

Utility model content

Based on this, it is necessary to provide a curved and swept blade and an axial flow fan, and the curved and swept blade can improve the working efficiency of the axial flow fan, thereby optimizing the performance of the axial flow fan.

A curved and swept blade, the curved and swept blade includes a pressure surface and a suction surface opposite to the pressure surface, the pressure surface is curved and swept forward toward the suction force, and the starting points of the forward curvature and the forward swept are the same, and the curved and swept forward The forward bending angle of the blade is 7°˜11°, and the swept blade has a variable ring volume index of -0.1˜-1.

In this way, the swept blade has the shape of a wide blade tip and a narrow blade root, and the pressure increases along the blade height, forming a pressure gradient from the blade root to the blade tip, which has advantages in anti-distortion, anti-surge, etc., not only improves the blade It can reduce the twist of the blade and reduce the weight of the blade, and it is also beneficial to the manufacture of the blade, avoiding the problems that the traditional blade twist angle is too large, the blade root is easy to stall and detach, and the blade is difficult to manufacture. Moreover, the curved and swept blades make the total pressure increase along the radius, so that the blade tip has a higher linear velocity, and the blade tip is used to reduce the loss of air volume and pressure, improve the aerodynamic efficiency, and thus enhance the working efficiency of the axial flow fan. The forward bending of the swept blade makes the leading edge and trailing edge of the blade have a larger offset in the radial direction compared to the traditional straight blade, thus staggering the phase angle of the noise source, and the force at the bending of the blade is fully decomposed , and then the speed of the noise changes quickly, and the noise reduction effect is obvious.

Further, the forward sweep angle of the curved and swept blades is 18°˜22°.

In this way, the forward sweep of the curved and swept blades enables the airflow to flow against the blades, reduces the energy loss at the inlet caused by the impact of the airflow and the blades, significantly increases the stable working range of the axial fan, and can optimize the overall performance of the axial fan. The leading edge and trailing edge of the blade have a large offset, which staggers the phase angle of the noise source, so that the noise superposition value of the blade in the radial direction becomes smaller, and the axial flow fan achieves the purpose of noise reduction.

Further, the connecting line between the midpoint of the blade root and the midpoint of the blade tip includes a straight line segment and a circular arc segment, wherein the length of the straight line segment is 0.4 to 0.5 times the height of the swept blade .

In this way, by controlling the ratio of the straight segment to the arc segment, the forward bending and forward sweeping angles of the swept blade can be optimized, the performance of the swept blade can be improved, and the gas flow, wind pressure and work efficiency of the swept blade can be improved.

Further, the blade tip has a leading edge fillet, and the blade root has a trailing edge fillet.

In this way, the swept blade has a smaller installation angle at the blade root, which can reduce the eddy current generated by the blade root and reduce the working noise of the axial flow fan. The blades of the curved and swept blades are curved and smooth, which can improve the flow efficiency of the gas, reduce the energy loss of the axial flow fan, and improve the working efficiency of the axial flow fan. At the same time, the rounded leading edge of the blade can improve the strength and stiffness of the swept blade, avoid the reduction of fatigue resistance of the swept blade caused by the sharp tip, thereby prolonging the service life of the swept blade.

Further, the airfoil of the swept blade is a single arc plate airfoil.

In this way, the curved and swept blades can improve the stability of the blades, so that the axial flow fan maintains good aerodynamic performance.

Further, the swept blade is a steel swept blade or an aluminum alloy swept blade.

In this way, the swept blade has the advantages of high specific modulus, high strength, good corrosion resistance, good processing performance and low cost, which improves the fatigue resistance of the swept blade and prolongs the service life of the swept blade.

An axial flow fan includes an impeller and a motor, the impeller is connected to the motor, the impeller includes a hub and swept blades, the swept blades are arranged along the circumferential direction of the hub, and the swept blades are the above-mentioned swept blades. swept blades.

In this way, the swept blade can significantly reduce the vortex of the blade root, so that the vortex noise is reduced, thereby avoiding energy loss. Moreover, the curved and swept blades make the axial flow fan have better aerodynamic performance and improve the working efficiency of the axial flow fan.

Further, there are at least two swept blades, and the at least two swept blades are evenly distributed along the circumferential direction of the hub.

In this way, the structure of the curved and swept blades is compact and has a large thrust, which reduces the capacity loss of the axial flow fan and optimizes the performance of the axial flow fan.

Further, at least two of the swept blades have the same thickness.

In this way, the thickness of the swept blades is the same, so that the pressure distribution of the swept blades is uniform, the interference between the blades is reduced, and the axial flow fan has a stable working state.

Description of drawings

1 is a schematic diagram of the pressure gradient distribution of a swept blade in an embodiment of the present invention;

2 is a schematic diagram of the inlet and outlet airflow velocity of the curved and swept blade in an embodiment of the present utility model;

3 is a schematic diagram of the angle of forward bending of the swept blade in an embodiment of the present invention;

Fig. 4 is the angle schematic diagram of the forward sweep of the swept blade in Fig. 3;

Fig. 5 is the structural representation of the swept blade in Fig. 3;

Fig. 6 is the structural representation of the swept blade in Fig. 3;

Fig. 7 is the structural representation of the curved and swept blade in Fig. 3;

8 is a schematic structural diagram of an impeller in an embodiment of the present invention.

Description of main component symbols: 10, swept blade; 11, blade tip; 12, blade root; 13, straight line segment; 14, arc segment; 15, leading edge fillet; 16, trailing edge fillet; 17, pressure surface 18, suction surface; 20, hub; 100, impeller, the following specific embodiments will further illustrate the present utility model in conjunction with the above drawings.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

It should be noted that when a component is referred to as being "mounted on" another component, it can be directly mounted on the other component or there may also be an intervening component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a co-existing centered component. When a component is said to be "fixed" to another component, it may be directly fixed to the other component or there may also be an intervening component.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Please refer to FIGS. 1 to 6 , FIG. 1 is a schematic diagram of the pressure gradient distribution of the curved and swept blade 10 in an embodiment of the present invention, and FIG. 2 is a schematic diagram of the inlet and outlet airflow velocity of the curved and swept blade 10 in an embodiment of the present invention. , FIG. 3 is a schematic diagram of the angle of the forward bending of the swept blade 10 in an embodiment of the present invention, FIG. 4 is a schematic diagram of the angle of the forward swept of the swept blade 10 in FIG. 3 , and FIG. Schematic diagram of the structure of the blade 10, FIG. 6 is a schematic diagram of the structure of the swept blade 10 in FIG. 3, FIG. 7 is a schematic diagram of the structure of the swept blade 10 in FIG. 3, and FIG. Schematic.

The curved and swept blade 10 provided by the present invention can optimize the performance of the blade, reduce the noise of the axial flow fan, and improve the working efficiency of the axial flow fan. Therefore, the curved and swept blade 10 can be applied to the fields of fans, compressors, fans, etc. .

The curved and swept blade 10 includes a pressure surface 17 and a suction surface 18 opposite to the pressure surface 17. The pressure surface 17 is curved forward and swept toward the suction surface 18, and the starting point of the forward curved and forward swept is the same. The forward bending angle is 7°˜11°, and the swept blade 10 has a variable ring volume index of -0.1˜-1.

In this embodiment, the swept blade 10 adopts the isolated airfoil method, and is mainly designed by using the data obtained from the aerodynamic test of the individual airfoil, so that it is suitable for the axial flow fan with small wind pressure and small blade consistency, and obtains better results. use effect.

Specifically, the airflow direction of the swept blade 10 is v. Considering the radial work added to the swept blade 10, this embodiment uses the variable circulation flow pattern of ΔCur=ΔCum(D _m /2) ^α = constant K to design the blade The pressure distribution is used to control the degree of twist of the swept blade, so that the pressure on different heights of the blade is distributed with a certain gradient, and the pressure from the tip 11 to the root 12 is gradually reduced to improve the stability of the swept blade. Among them, ΔCum is the circumferential component of the gas velocity at the impeller outlet, D _m is the radius of the airfoil section, ΔCur represents the degree of circulation change, which is a constant K, α is the variable circulation index, the choice of α It directly affects the distribution of the flow velocity at the impeller outlet, which in turn affects the aerodynamic performance of the axial flow fan.

Specifically, the value range of the variable circulation index is -0.1 to -1, so that the pressure increases along the blade height, forming a pressure gradient from the blade root 12 to the blade tip 11, and forming the blade tip 11 wide and the blade root 12 narrow. The shape can improve the stability of the root of the swept blade 10, and avoid the blade root 12 from being twisted too much, resulting in blade breakage. At the same time, the total pressure increases along the blade height, and the axial flow fan can make full use of the higher linear speed at the tip 11, reduce the loss of air volume and pressure, improve the aerodynamic efficiency, and expand the working area, thereby improving the working efficiency of the axial flow fan. Moreover, a negative variable circulation index can also reduce the eddy current at the blade root, avoid energy loss, and reduce the working noise caused by the eddy current.

Considering that the overall shape of the swept blade 10 is a blade root 12 with a narrow blade tip 11, the weight of the swept blade 10 is reduced, which makes the swept blade 10 easy to manufacture and avoids the low pressure coefficient and distortion of the single-plate blade. If the angle is large, the eddy current of the blade root 12 can be reduced, the eddy current noise can be reduced, and the capacity loss caused by the eddy current can be prevented.

Moreover, the curved and swept blades 10 make the total pressure of the axial flow fan increase along the radius, so that the blade tip 11 has a higher linear velocity, and the blade tip 11 is used to reduce the loss of air volume and pressure, improve the aerodynamic efficiency, and thereby enhance the axial flow fan. work efficiency.

In this embodiment, the swept blade 10 sets the forward bending angle and the forward sweeping angle of the blade through the center of gravity stacking line, so that the blade has both forward bending in the rotation direction and forward sweeping in the airflow direction. Therefore, considering the swept design of the blade, that is, the angle of forward bending and swept of the blade, the leading edge and trailing edge of the blade have a larger offset in the radial direction compared to the traditional straight blade, thereby staggering the noise. The phase angle of the source reduces the noise superposition value of the blade in the radial direction, and the axial flow fan achieves the purpose of noise reduction.

Specifically, the pressure surface 17 of the swept blade 10 is bent forward toward the suction surface 18 , the center of gravity of the blade ADB is inclined toward the rotation direction u of the impeller, that is, the circumferential direction is inclined, the midpoint A of the blade root 12 and the midpoint of the blade tip 11 The included angle θsk between the connecting line AB of the point B and the radial vertical line OC is the forward bending angle. The forward bending angle of the swept blade 10 is 7° to 11°, so that the force at the bend of the blade is fully decomposed, and the speed of the noise changes quickly, and the noise reduction effect is obvious. The connecting line AB includes a straight line segment AD and a circular arc segment DB, and the length L ₁ of AD is 0.4 to 0.5 times the height H ₁ of the swept blade 10 .

At the same time, the pressure surface 17 of the swept blade 10 is swept forward toward the suction surface 18 , the center of gravity of the blade EFH is inclined toward the airflow direction v, that is, the chord length direction is inclined, the midpoint E of the blade root 12 and the midpoint H of the blade tip 11 The included angle θsw between the connecting line EH and the radial vertical line SH is the forward sweep angle. The swept-forward angle of the swept blade 10 is 18° to 22°, so that the airflow can flow close to the blade, reducing the inlet energy loss caused by the impact of the airflow and the blade, significantly increasing the stable working range of the axial flow fan, and optimizing the axial flow The overall performance of the fan. The connecting line EH includes a straight line segment EF and a circular arc segment FH, and the length L ₂ of EH is 0.4 to 0.5 times the height H ₂ of the swept blade 10 .

Therefore, the connecting line between the midpoint of the blade root 12 and the midpoint of the blade tip 11 includes a straight segment 13 and a circular arc segment 14. The length of the straight segment 13 is 0.4 to 0.5 times the height of the swept blade 10. By controlling the straight segment The ratio of 13 to the arc segment 14 can optimize the forward bending and forward sweeping angles of the swept blade 10 , improve the performance of the swept blade 10 , and thereby improve the gas flow, wind pressure and work efficiency of the swept blade 10 .

Taking into account the strength of the swept blade 10 , the tip 11 , the blade root 12 and the blade body of the swept blade 10 are rounded and noise-reduced, so that the blade tip 11 has a leading edge fillet 15 and the blade root 12 has a trailing edge Rounded corners 16. The fillet 16 of the trailing edge of the blade root 12 is relatively smooth, which can reduce the eddy current generated by the blade root 12, thereby reducing the working noise of the fan. The rounded leading edge of the blade tip 11 can improve the strength and stiffness of the swept blade 10, improve the fatigue resistance of the swept blade 10, prolong the service life, and prevent the blade from being insufficient in strength due to the sharp blade tip during use. . At the same time, the blade body of the swept blade 10 is curved and smooth, which can improve the flow efficiency of the gas and enhance the efficiency of the axial flow fan.

In the present embodiment, the airfoil of the swept blade 10 is preferably a single arc plate type airfoil. According to the process requirements, the angle of attack and the aspect ratio of the swept blade 10 are reasonably optimized to obtain the swept blade 10 with excellent performance. The curved and swept blades 10 have better stability, so that the axial flow fan has better aerodynamic performance.

It can be understood that this embodiment does not limit the airfoil of the swept blade 10, and the airfoil of the swept blade 10 also includes one of a flat-concave airfoil, a flat airfoil, or a circular arc plate airfoil.

In this embodiment, considering the strength, stability, use effect and cost of the swept blade 10, the swept blade 10 is preferably a swept steel blade or an aluminum alloy swept blade. The swept blade 10 has the advantages of high specific modulus, high strength, good corrosion resistance, good processing performance and low cost, which improves the fatigue resistance of the swept blade 10 and prolongs the service life of the swept blade 10.

It can be understood that this embodiment does not limit the type of the swept blade 10, and the swept blade 10 further includes titanium alloy swept blade, resin-based composite swept blade, metal-based composite swept blade, ceramic matrix composite swept blade or carbon fiber One of the composite curved and swept blades, which can expand the application range of fans and meet the needs of special fields, such as aero-engine cold-end components.

The present invention also provides an axial flow fan (not shown in the figure), the axial flow fan includes an impeller 100 and a motor (not shown in the figure), the impeller 100 is connected to the motor, and the impeller 100 includes a hub 20 and swept blades 10. The swept blades 10 are disposed along the circumferential direction of the hub 20 , and the swept blades 10 are the swept blades 10 .

The application of the above-mentioned curved and swept blades 10 to the axial flow fan can reduce the energy loss of the axial flow fan and improve the working efficiency of the axial flow fan, thereby optimizing the performance of the axial flow fan and expanding the application range of the axial flow fan.

Specifically, there are at least two swept blades 10 , and the at least two swept blades 10 are evenly distributed along the circumferential direction of the hub 20 , so that the swept blades 10 have greater thrust, which is beneficial to improve the efficiency of the fan. Moreover, the swept blade 10 has a compact structure and has good aerodynamic performance.

Further, the thicknesses of at least two swept blades 10 are the same, so that the pressure distribution of the swept blades 10 is uniform, the interference between the blades is reduced, and a stable working state is maintained. It can be understood that the swept blade 10 is a plate-type airfoil of equal thickness as a whole. Therefore, the swept blade 10 can be processed by molding, which has the advantages of simple operation and low cost, thereby further reducing the manufacturing cost of the fan.

It can be understood that the present embodiment does not limit the processing method of the swept blade 10, and the swept blade 10 can also be formed by casting or machining.

The curved and swept blades 10 of the axial flow fan provided by the utility model can significantly improve the wind pressure and work efficiency of the axial flow fan, and effectively solve the problems of the excessive torsion angle of the equal-circle blades, the easy stall separation of the blade root 12, the difficulty in manufacturing and the like. Poor performance and other problems, but also has a good noise reduction effect.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present utility model, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the utility model patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for this utility model shall be subject to the appended claims.

Claims (9)

1. a curved and swept blade, the curved and swept blade comprises a pressure surface and a suction surface opposite to the pressure surface, and the pressure surface is bent and swept forward toward the suction force, and the starting point of the forward bending and the swept forward is the same, and it is characterized by: The forward bending angle of the swept blade is 7°˜11°, and the swept blade has a variable ring volume index of −0.1˜−1. 2 . The curved and swept blade according to claim 1 , wherein the forward sweep angle of the curved and swept blade is 18°˜22°. 3 . 3 . The swept blade according to claim 1 , wherein the swept blade has a blade tip and a blade root, and the connecting line between the midpoint of the blade root and the midpoint of the blade tip comprises a straight segment. 4 . and a circular arc segment, wherein the length of the straight line segment is 0.4 to 0.5 times the height of the curved and swept blade. 4. The swept blade of claim 1, wherein the swept blade has a blade tip and a blade root, the blade tip has a leading edge fillet, and the blade root has a trailing edge fillet. 5 . The swept blade according to claim 1 , wherein the airfoil of the swept blade is a single arc plate type airfoil. 6 . 6 . The swept blade according to claim 1 , wherein the swept blade is a steel swept blade or an aluminum alloy swept blade. 7 . 7. An axial flow fan, comprising an impeller and a motor, the impeller is connected to the motor, the impeller comprises a hub and a swept blade, and the swept blade is arranged along the circumference of the hub, characterized in that the The swept blade is the swept blade according to any one of claims 1 to 6. 8 . The axial flow fan according to claim 7 , wherein there are at least two swept blades, and the at least two swept blades are evenly distributed along the circumferential direction of the hub. 9 . 9 . The axial flow fan according to claim 7 , wherein at least two of the swept blades have the same thickness. 10 .

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