WO2020077916A1 - Counter-rotating fan - Google Patents

Abstract

A counter-rotating fan. The fan (100) comprises a first stage impeller (2) and a second stage impeller (5), of which the rotation directions are opposite. The first stage impeller (2) and the second stage impeller (5) are driven by two mutually independent drive mechanisms. The first stage impeller (2) comprises multiple first blades (21) arranged circumferentially at intervals, and the second stage impeller (5) comprises multiple second blades (51) arranged circumferentially at intervals . The pressure surfaces (P _S) of the first blades (21) are arranged to be opposite the suction surfaces (S _S) of the second blades (51), the bending directions of the first blades (21) and of the second blades (51) being opposite. The fan can output a wind field of a large flow and at a long distance.

Description

Counter-rotating fan

Cross-reference of related applications

This application is based on a Chinese patent application with an application number of 201811198041.0 and an application date of October 15, 2018 and a Chinese patent application with an application number of 201821672644.5 and an application date of October 15, 2018, and requests the priority of the aforementioned Chinese patent application The entire content of the aforementioned Chinese patent application is hereby incorporated by reference.

Technical field

The invention relates to the technical field of fans, in particular to a counter-rotating fan.

Background technique

The wind field of traditional fans is generally a rotating vortex ring wind field. This kind of wind field has large energy loss, insufficient wind strength, short air supply distance, large wind field pulsation, and poor user satisfaction. Since the traditional fans are mostly single-stage axial fans, such fans have a single air supply field, which is not adjustable nor variable.

Summary of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a counter-rotating fan.

A counter-rotating fan according to an embodiment of the present invention includes a first-stage impeller and a second-stage impeller that rotate in opposite directions. The first-stage impeller and the second-stage impeller are driven by two independent drive mechanisms. The first stage impeller includes a plurality of circumferentially spaced first blades, the second stage impeller includes a plurality of circumferentially spaced second blades, the pressure surface of the first blade and the suction force of the second blade The surfaces are arranged oppositely, and the bending directions of the first blade and the second blade are opposite.

According to the counter-rotating fan of the embodiment of the present invention, since the two-stage impeller rotates in the opposite direction and the blade bending direction is opposite, the airflow generated by the two-stage impeller rotates in the opposite direction. When the two airflows meet, derotation and endurance can occur. Under reasonable conditions, the fan can output a wind field with high wind pressure and strong power, and can also output a wind field with large flow and long distance. In addition, because the driving mechanisms of the two-stage impeller are independent of each other, the counter-rotating fan can obtain an adjustable and controllable wind field, which improves user satisfaction.

According to some embodiments of the present invention, the angle between the inlet angle of the second blade and the reference angle of the first blade does not exceed 5 °, wherein, the angle of the reference angle of the first blade is calculated according to the speed triangle The angle and the flow coefficient of the inlet angle of the first blade are two parameters of the speed triangle.

According to an embodiment of the present invention, the angle between the outlet angle of the second blade and the inlet angle of the first blade does not exceed 10 °, and the tangent of the reference angle of the first blade is positively correlated with the first variable Relationship, the tangent of the first blade reference angle has a negative correlation with a second variable, the first variable is the product of the flow coefficient and the tangent of the inlet angle of the first blade, the second variable Is the sum of the flow coefficient and the tangent of the inlet angle of the first blade.

According to an embodiment of the present invention, the angle between the exit angle of the second blade and the entrance angle of the first blade does not exceed 10 °, and the angle between the entrance angle of the second blade and the reference angle of the first blade The angle difference is not more than 5 °, the inlet angle of the first blade is W1, the reference angle of the first blade is W3t, W1, W3t satisfy the relationship: W3t = arctan {Fi * tan (W1) / [Fi + tan (W1)]}, Fi is the flow coefficient.

According to an embodiment of the present invention, the axial width of the first blade is at least 0.9 times the axial width of the second blade, and the axial width of the first blade does not exceed the axial width of the second blade 1.5 times the width.

According to an embodiment of the present invention, the minimum axial gap between the first blade and the second blade is at least 0.1 times the axial width of the first blade, and does not exceed the first blade's 0.8 times the axial width.

According to an embodiment of the present invention, the diameter of the hub of the first-stage impeller is at least 0.8 times the diameter of the hub of the second-stage impeller, and the diameter of the hub of the first-stage impeller does not exceed the hub of the second-stage impeller 1.1 times the diameter.

According to an embodiment of the present invention, the rim diameter of the first-stage impeller is at least 0.9 times the rim diameter of the second-stage impeller, and the rim diameter of the first-stage impeller does not exceed the second-stage 1.2 times the rim diameter of the impeller.

According to an embodiment of the present invention, the two edges of the first blade in the circumferential direction are the first leading edge and the first trailing edge, respectively, and the center between the blade tip and the root end of the first trailing edge The angle is at least 1.5 times the central angle between the blade tip and the root end of the first leading edge, and the central angle between the blade tip and the root end of the first trailing edge does not exceed the first front The central angle between the leaf tip and the root end of the margin is 2.2 times.

According to an embodiment of the present invention, the two edges of the second blade in the circumferential direction are a second leading edge and a second trailing edge, respectively, and the center between the tip and root ends of the second trailing edge The angle is at least 1.4 times the central angle between the leaf tip and the root end of the second leading edge, and the center angle between the leaf tip and the root end of the second trailing edge does not exceed the second front The central angle between the tip of the leaf and the root of the leaf is 2.1 times the central angle.

According to an embodiment of the present invention, the number of the first blades is less than the number of the second blades, or the number of the first blades is more than the number of the second blades; when the number of the first blades When it is less than the number of the second blades, the difference between the number of the second blades and the first blades does not exceed 2; when the number of the first blades is more than the number of the second blades , The number of the first blades will not exceed twice that of the second blades.

According to an embodiment of the present invention, the rotation speed of the first-stage impeller is equal to the rotation speed of the second-stage impeller, so that the wind field formed by the counter-rotating fan is a straight wind field.

According to an embodiment of the present invention, the rotation speed of the first-stage impeller is not equal to the rotation speed of the second-stage impeller, so that the wind field formed by the counter-rotating fan is an annular vortex wind field with a diffusion cone angle.

According to an embodiment of the present invention, the first-stage impeller and the second-stage impeller constitute a wind wheel group, and the counter-rotating fan includes a plurality of the wind wheel groups distributed in the axial direction.

According to an embodiment of the present invention, the blade shape of the first blade and the blade shape of the second blade are different.

According to an embodiment of the present invention, the rim diameter of the first blade is equal to the rim diameter of the second blade, or the rim diameter of the first blade is not equal to the rim diameter of the second blade.

Additional aspects and advantages of the present invention will be partially given in the following description, and some will become apparent from the following description, or be learned through the practice of the present invention.

Additional aspects and advantages of the present invention will be partially given in the following description, and some will become apparent from the following description, or be learned through the practice of the present invention.

BRIEF DESCRIPTION

The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

FIG. 1 is an overall structural diagram of a counter-rotating fan according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a first-stage impeller and a second-stage impeller according to an embodiment of the present invention.

3 is a schematic diagram of a wind field when the two-stage impeller of the counter-rotating fan has the same rotation speed according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of the wind field when the rotation speeds of the two-stage impeller of the counter-rotating fan according to an embodiment of the present invention are not equal.

FIG. 5 is a schematic diagram of the outlet diffusion cone angle when the rotation speeds of the two-stage impeller of the counter-rotating fan of the embodiment of the present invention are approximately equal.

6 is a schematic diagram of the outlet diffusion cone angle when the two-stage impeller rotation speed of the counter-rotating fan of the embodiment of the present invention is large.

7 is a line graph of the PIV axial plane velocity field test results when the two-stage impeller of the counter-rotating fan of the embodiment of the present invention has the same rotational speed.

8 is a line graph of the PIV axial plane velocity field test result when the two-stage impeller speed ratio of the counter-rotating fan of the embodiment of the present invention is greater than 1. FIG.

9 is a line graph of the PIV axial plane velocity field test result when the two-stage impeller speed ratio of the counter-rotating fan of the embodiment of the present invention is less than 1. FIG.

10 is an explanatory diagram of parameter definitions of the first blade and the second blade of the counter-rotating fan according to an embodiment of the present invention.

FIG. 11 is a schematic diagram of blade type parameter definition of a first blade of a counter-rotating fan according to an embodiment of the present invention.

12 is a schematic diagram of the definition of the blade shape parameters of the second blade of the counter-rotating fan according to an embodiment of the present invention.

13 is a schematic structural diagram of a first-stage impeller and a second-stage impeller according to another embodiment of the present invention.

Fig. 14 is a diagram showing the correspondence between the axial minimum clearance of the first-stage impeller and the second-stage impeller and the rotation noise.

Reference mark:

Counter-rotating fan 100, air intake grille 1, first-stage impeller 2, first blade 21, first hub 22, first drive assembly 3, motor bracket 4, second-stage impeller 5, second blade 51, second Hub 52, second drive assembly 6, air outlet grille 7, first-stage air guide ring 8, second-stage air guide ring 9,

The first leaf type BS1, the second leaf type BS2,

The first leading edge LE1, the first trailing edge TE1, the second leading edge LE2, the second trailing edge TE2,

Pressure surface Ps, suction surface Ss.

detailed description

Hereinafter, embodiments of the present invention will be described in detail. Examples of the embodiments are shown in the drawings, in which the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention, and cannot be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The azimuth or positional relationship indicated by "radial", "circumferential", etc. is based on the azimuth or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the device or element referred to It must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise stated, "plurality" means two or more.

In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be fixed connection or detachable Connected, or connected integrally; either mechanically or electrically; directly connected, or indirectly connected through an intermediary, or internally connected between two components. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood in specific situations.

The counter-rotating fan 100 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 13.

As shown in FIGS. 1-2 and 13, a counter-rotating fan 100 according to an embodiment of the present invention includes a first-stage impeller 2 and a second-stage impeller 5 with opposite rotation directions, and a first-stage impeller 2 and a second-stage The impeller 5 is driven by two independent drive mechanisms, the first-stage impeller 2 includes a plurality of circumferentially spaced first blades 21, and the second-stage impeller 5 includes a plurality of circumferentially spaced second blades 51, the first The pressure surface Ps of the blade 21 (that is, the inner concave surface shown in FIG. 10) is opposite to the suction surface Ss of the second blade 51 (that is, the outer convex surface shown in FIG. 10). in contrast.

It should be noted that the counter-rotating fan 100 according to the embodiment of the present invention can be applied to electric fans, circulation fans, ventilation fans, air-conditioning fans, and other devices that need to send out air. The counter-rotating fan 100 according to the embodiment of the present invention is mainly used to promote airflow Not heat transfer.

It can be understood that, since the counter-rotating fan 100 of the embodiment of the present invention includes two-stage impellers, the rotation of the first-stage impeller 2 will form a circular vortex-like wind flow, when the second-stage impeller 5 and the first-stage impeller 2 rotate simultaneously Under the influence of the wind field of the second-stage impeller 5, the circumferential vortex-shaped wind flow formed by the rotation of the first-stage impeller 2 will exhibit the phenomenon of spin and endurance. However, the difference in the structural parameters of the first-stage impeller 2 and the second-stage impeller 5 and the difference in the rotational speeds of the two will result in different results of wind flow race and endurance. In some cases, the fan will output a wind field with high wind pressure and strong power, and in some cases, the fan will output a large-volume, long-distance wind field.

At the same time, since the first-stage impeller 2 and the second-stage impeller 5 are driven by two mutually independent drive mechanisms, the speed ratio of the first-stage impeller 2 and the second-stage impeller 5 can be adjusted, so that at different speeds In contrast, the counter-rotating fan 100 can output wind fields with different characteristics, thereby enriching the output wind field types of the counter-rotating fan 100 and improving user satisfaction.

According to the counter-rotating fan 100 according to the embodiment of the present invention, since the counter-rotating fan 100 includes two-stage impellers with opposite rotation directions and opposite blade bending directions, the fan can output a high wind pressure and strong wind field under different parameter conditions. It can output large flow and long distance wind field. Since the driving mechanisms of the two-stage impeller are independent of each other, the counter-rotating fan 100 can obtain an adjustable and controllable wind field, which improves user satisfaction.

In some embodiments, as shown in FIG. 10, the inlet angle of the first blade 21 is W1, the inlet angle of the second blade 51 is W3, and the outlet angle of the second blade 51 is W4.

It can be understood that the size of the inlet angle W1 of the first blade 21, the inlet angle W3 and the outlet angle W4 of the second blade 51 affect the air output characteristics of the first-stage impeller 2 and the second-stage impeller 5 to a certain extent.

Studies have shown that the first blade 21 has a speed triangle at the entrance and exit wind speed, and the second blade 51 has a speed triangle at the entrance and exit wind speed. Under ideal plane cascade flow, the outlet angle W4 of the second blade 51 is equal to the inlet angle W1 of the first blade 21 (ie W1 = W4), and the inlet angle W3 of the second blade 51 is equal to the reference angle of the first blade. The air volume of the machine is large, and the air supply distance is long.

However, considering the influence of the limited number of blades and slippage, the speed triangle will have a certain angle of lag and deviation, so the inlet angle W3 of the second blade 51 and the outlet angle W4 of the second blade 51 are preferably angled relative to the ideal angle, but The angle adjustment should not be too large.

Specifically, the angle between the inlet angle W3 of the second blade 51 and the reference angle W3t of the first blade does not exceed 5 °, that is, W3t-5 ° ≦ W3 ≦ W3t + 5 °. The speed triangle of the second blade 51 at the inlet can be as close as possible to the ideal speed triangle, which is advantageous for the contra-rotating fan 100 to obtain good performance. Here, the first blade reference angle W3t is calculated according to the speed triangle, and the inlet angle W1 and the flow coefficient Fi of the first blade 21 are two parameters of the speed triangle. The flow coefficient Fi is a well-known common-sense concept in the field of fluid mechanics, and its definition will not be described here.

More specifically, the tangent of the first blade reference angle W3t has a positive correlation with the first variable. The so-called positive correlation means that when the first variable increases, the tangent of the first blade reference angle W3t increases accordingly; When the first variable decreases, the tangent of the first blade reference angle W3t decreases accordingly. The tangent of the first blade reference angle W3t has a negative correlation with the second variable. The so-called negative correlation means that when the second variable increases, the tangent of the first blade reference angle W3t decreases; when the first When the two variables decrease, the tangent of the first blade reference angle W3t increases accordingly. The first variable is the product of the flow coefficient Fi and the tangent of the inlet angle W1 of the first blade 21, and the second variable is the sum of the flow coefficient Fi and the tangent of the inlet angle W1 of the first blade 21.

In a specific example, W3t satisfies the relationship: W3t = arctan {Fi * tan (W1) / [Fi + tan (W1)]}.

In addition, the difference between the outlet angle W4 of the second blade 51 and the inlet angle W1 of the first blade 21 does not exceed 10 °, that is, W1-10 ° ≦ W4 ≦ W1 + 10 °. The speed triangle of the second blade 51 at the inlet can be as close as possible to the ideal speed triangle, which is advantageous for the contra-rotating fan 100 to obtain good performance.

In some embodiments, as shown in FIG. 10, the axial width of the first blade 21 is B1, the axial width of the second blade 51 is B2, and the axial width B1 of the first blade 21 is at least that of the second blade 51 0.9 times the axial width B2, the axial width B1 of the first blade 21 does not exceed 1.5 times the axial width B2 of the second blade 51. That is, B1 and B2 satisfy the relationship: 0.9 * B2≤B1≤1.5 * B2. It can be understood that, in general, the total axial width of the counter-rotating fan 100 is limited, and a reasonable distribution of the axial widths of the first blade 21 and the second blade 51 is beneficial to ensure the wind output characteristics of the cyclone fan 100. According to multiple tests, when the B1 / B2 is in the range of 0.9-1.5, the counter-rotating fan 100 has better air output characteristics. At this time, the air output of the counter-rotating fan 100 is larger and the air supply distance is longer.

Advantageously, B1 and B2 satisfy the relationship: 1.2 * B2≤B1≤1.4 * B2. Of course, what needs to be explained here is that the values of B1 and B2 are not limited to the above ranges, and in practical applications B1 and B2 can be adjusted adaptively according to actual needs.

Here, when the axial width B1 of the first blade 21 is too long, the flow loss increases, and at the same time, the axial size of the counter-rotating fan 100 increases, which is not conducive to application; the axial width B1 of the first blade 21 is too short, the first One blade 21 does not form a stable and uniform flow, which is not conducive to the flow guide inside the second blade 51.

Studies have shown that the axial width of the front and rear two-stage blades remains B1 = 1.3 * B2, that is, the axial width B1 of the first blade 21 is at least 1.3 times the axial width B2 of the second blade 51. The fan can have better flow distribution and performance, but considering the consideration of different forms of wind field and variable speed requirements, the range of the axial width B1 of the first blade 21 is appropriately widened, which can better compromise B1 too long or too Short-term problems.

In some embodiments, as shown in FIG. 10, the minimum axial gap between the first blade 21 and the second blade 51 is Bg, and the axial width of the first blade 21 is B1. Bg and B1 satisfy the relationship: 0.1 * B1≤Bg≤0.8 * B1. It can be understood that the size of the axial gap between the first blade 21 and the second blade 51 can directly affect the performance of the output wind field of the counter-rotating fan 100. When Bg / B1 is in the range of 0.1-0.8, the counter-rotating fan 100 Can have better wind characteristics.

Specifically, the rotation direction of the air flow between the first blade 21 and the second blade 51 is opposite, and the mixing and mutual interference are serious. If the distance between the two is too long, the flow loss will increase, and the axial size will increase at the same time. If the distance between the two is too short, it will be affected by product application safety issues. On the other hand, the gap will be too small, making the first blade The downstream 21 has no effect on the formation of a stable and uniform flow, which leads to a large attenuation of the performance of the second blade 51. Studies have shown that when the value of Bg is 0.5 times B1, it has a good compromise effect. However, considering the blade size and other factors, when the axial width B1 of the first blade 21 is small, the ideal value of the axial minimum gap Bg is Bg = 0.8 * B1; conversely, when the axial width B1 of the first blade 21 is relatively small When it is large, the ideal value of the minimum axial clearance Bg is Bg = 0.1 * B1, so the range of 0.1 * B1≤Bg≤0.8 * B1 is the result of comprehensive consideration of the blade size.

Advantageously, Bg satisfies the relationship: 10mm≤Bg≤20mm. Of course, it should be noted here that the value of Bg is not limited to the above range, and in practical applications, Bg can be adjusted adaptively according to actual needs.

In some embodiments, as shown in FIGS. 11-12, the hub diameter of the first-stage impeller 2 is D01, and the hub diameter of the second-stage impeller 5 is D02, and D01 and D02 satisfy the relationship: 0.8≤D01 / D02 ≤1.1. It can be understood that the size of D01 / D02 directly affects the superposition relationship between the wind field output by the first-stage impeller 2 and the wind field output by the second-stage impeller 5. According to multiple tests, when D01 / D02 is in the range of 0.8-1.1, the interaction between the wind field output by the first-stage impeller 2 and the wind field output by the second-stage impeller 5 is relatively strong, thereby ensuring the output of the rotary fan 100 It can output wind field with large wind pressure and long supply distance. Of course, what needs to be explained here is that the specific ratio of D01 and D02 can be adjusted according to actual needs and is not limited to the above range.

In theory, the hub of the first-stage impeller 2 and the hub of the second-stage impeller 5 will have better aerodynamic characteristics when the diameters are equal. However, in some operating conditions in actual applications, considering the large difference in load between the two-stage impellers, the size of the motor needs to be different. Therefore, according to the current test application research results, the hub diameter D01 of the first-stage impeller 2 and the second-stage impeller The hub diameter D02 of 5 is preferably within the interval 0.8≤D01 / D02≤1.1.

In some embodiments, as shown in FIGS. 11-12, the rim diameter of the first-stage impeller 2 is D1, and the rim diameter of the second-stage impeller 5 is D2, and D1 and D2 satisfy the relationship: 0.9 * D2 ≤D1≤1.2 * D2. The size of D1 / D2 directly affects the superposition relationship between the wind field output by the first-stage impeller 2 and the wind field output by the second-stage impeller 5. According to several tests, when D1 / D2 is in the range of 0.9-1.2, the interaction between the wind field output by the first-stage impeller 2 and the wind field output by the second-stage impeller 5 is relatively strong, thereby ensuring the output of the counter-rotating fan 100 It can output wind field with large wind pressure and long supply distance. Advantageously, D1 / D2 = 1, ie D1 = D2. Of course, it should be noted here that the specific ratio of D1 and D2 can be adjusted according to actual needs, and is not limited to the above range.

Theoretically, the rim diameters of the first-stage impeller 2 and the second-stage impeller 5 are equal, and they will have better aerodynamic characteristics. However, in practical applications, considering the industrial design appearance, structural size restrictions and other factors, there is usually a design that reduces or increases the diameter of a certain impeller. Therefore, according to the current application research results, the rim diameter D1 of the first-stage impeller 2 and the rim diameter D2 of the second-stage impeller 5 are limited to the range 0.9 * D2≤D1≤1.2 * D2.

In some embodiments, as shown in FIG. 11, the two edges of the first blade 21 in the circumferential direction are the first leading edge LE1 and the first trailing edge TE1, respectively, the leaf tip and leaf root of the first leading edge LE1 The center angle between the ends is W5, the center angle between the tip of the first trailing edge TE1 and the root end is W6, and W5 and W6 satisfy the relationship: 1.5 * W5≤W6≤2.2 * W5. It can be understood that the shapes of the first leading edge LE1 and the first trailing edge TE1 of the first blade 21 have a greater influence on the output wind field of the first-stage impeller 2, while W5 and W6 are respectively determined to a certain extent The degree of curvature of the first leading edge LE1 and the first trailing edge TE1 has been tested, and a large number of experiments have proved that W6 / W5 in the range of 1.5-2.2 can ensure that the first-stage impeller 2 has better wind characteristics, and To a certain extent, the noise generated when the first-stage impeller 2 rotates is reduced. Of course, what needs to be explained here is that the ratio of W6 / W5 can be adjusted according to the requirements of the wind farm, and is not limited to the above range.

It can be seen that the limitation of the two angular parameters W5 and W6 is aimed at controlling the curvature of the first leading edge LE1 and the first trailing edge TE1 of the first blade 21 to control the internal flow of the first-stage impeller 2 and optimize Pneumatic design. The research shows that when 1.5 * W5≤W6≤2.2 * W5, within this range, the downstream inter-stage interference of the first-stage impeller 2 can be effectively controlled, weakening the mutual influence of the two stages, reducing noise, improving wind pressure and other performance.

In some embodiments, as shown in FIG. 12, the two edges of the second blade 51 in the circumferential direction are the second leading edge LE2 and the second trailing edge TE2, respectively, the leaf tip and the leaf root of the second leading edge LE2 The center angle between the ends is W7, the center angle between the tip of the leaf and the root end of the second trailing edge TE2 is W8, and W7 and W8 satisfy the relationship: 1.4 * W7≤W8≤2.1 * W7. It can be understood that the shapes of the second leading edge LE2 and the second trailing edge TE2 of the second blade 51 have a greater influence on the output wind field of the second-stage impeller 5, while W7 and W8 are respectively determined to a certain extent The second leading edge LE2 and the second trailing edge TE2 are bent. After a lot of experiments, it has been proved that W8 / W7 in the range of 1.4-2.1 can ensure that the second-stage impeller 5 has good wind output characteristics, and To a certain extent, the noise generated when the second-stage impeller 5 rotates is reduced. Of course, what needs to be explained here is that the ratio of W8 / W7 can be adjusted according to the requirements of the wind farm, and it is not limited to the above range. Advantageously, the first leading edge LE1 bends in the direction of rotation of the first-stage impeller 2 and the second leading edge LE2 bends in the direction of rotation of the second-stage impeller 5.

It can be seen that the limitation of the two angular parameters W7 and W8 is aimed at controlling the curvature of the second leading edge LE2 and the second trailing edge TE2 of the second blade 51 to control the internal flow of the second-stage impeller 5 and optimize Pneumatic design. Studies have shown that: 1.4 * W7≤W8≤2.1 * W7, within this range, the downstream dynamic and static interference of the second-stage impeller 5 can be effectively controlled, weakening the interaction with the downstream parts (such as motor support, net cover and other structures), reducing Noise, wind pressure and other performance.

As shown in FIG. 11, the first-stage impeller 2 includes a first hub 22 and a first blade 21 provided on the first hub 22. The cylindrical surface diameter of the first hub 22 is D01, and the cylindrical diameter of the rim is D1. A blade 21 is composed of a stack of first airfoils BS1 with different diameters Dx1 (D01≤Dx1≤D1). The shape of the first airfoils BS1 is shown in FIG. 11.

As shown in FIG. 12, the second-stage impeller 5 includes a second hub 52 and a second blade 51 provided on the second hub 52. The cylindrical diameter of the second hub 52 is D02, and the cylindrical diameter of the rim is D2. The two blades 51 are composed of a stack of second blades BS2 with different diameters Dx2 (D02 ≦ Dx2 ≦ D2). The shape of the second blade BS2 is shown in FIG. 12.

In some embodiments, the number of first blades 21 is BN1, and the number of second blades 51 is BN2. BN1 and BN2 satisfy the relationship: BN2-2≤BN1≤2 * BN2. Here, the number of first blades 21 may be less than the number of second blades 51, and the number of first blades 21 may also be greater than the number of second blades 51. When the number of first blades 21 is less than the number of second blades 51, the difference between the number of second blades 51 and first blades 21 does not exceed 2; when the number of first blades 21 is more than that of second blades 51 In terms of number, the number of first blades 21 will not exceed twice that of second blades 51.

Among them, the number of first blades 21 is one of the main factors affecting the frequency or internal turbulence. After considering the blade size and blade consistency factors, the number of first blades 21 BN1 is summarized and studied in the above range. Can meet the needs of counter-rotating fans of different sizes.

It can be understood that the values of BN1 and BN2 will directly affect the wind field superposition results of the first-stage impeller 2 and the second-stage impeller 5, according to actual experiments, when BN1 and BN2 satisfy the relationship: BN2-2≤BN1≤2 * BN2, the wind field superposition effect of the first-stage impeller 2 and the second-stage impeller 5 is the best, and the wind output characteristics of the counter-rotating fan 100 are better ensured.

Of course, in other embodiments of the present invention, the values of BN1 and BN2 can be specifically selected according to actual conditions, and are not limited to the above range.

After a fan leaves the factory, the structural parameters usually cannot be changed, and the wind field formed by the fan operation is also relatively single. Although the structural parameters of the counter-rotating fan 100 of the embodiment of the present invention cannot be changed after delivery, the speed ratio of the two-stage impeller can be adjusted, and the fan can obtain different wind fields at different speed ratios. The following describes the wind field when the fan speed ratio is different when the structural parameters are fixed. Of course, the changes in the wind field conditions obtained at a certain speed ratio are based on the premise that the fan structural parameters are fixed, relative to the wind fields obtained at other speed ratios.

As shown in FIG. 3, the rotation speed of the first-stage impeller 2 is equal to the rotation speed of the second-stage impeller 5, and the wind field formed by the counter-rotating fan 100 at this time can be regarded as a straight wind field. It can be understood that the wind field output by the conventional fan is an annular vortex wind field, which has a large energy loss, a small wind force, and a short air supply distance. In the counter cyclone of the embodiment of the present invention, when the rotational speeds of the first-stage impeller 2 and the second-stage impeller 5 are equal, the wind field of the second-stage impeller 5 will spin and endure the wind field of the first-stage impeller 2 Therefore, the wind field input to the rotary fan 100 is formed into a focused straight wind field. This wind field has a longer air supply distance, more uniform wind pressure, and better wind field characteristics. Of course, what needs to be explained here is that, as shown in FIG. 5, in actual application, the rotation speed of the first-stage impeller 2 and the rotation speed of the second-stage impeller 5 will inevitably deviate, but the difference is very small. Due to the deviation of the two-stage impeller speed, even if the deviation angle is small, the output wind field will have a certain exit cone angle. At this time, the outlet cone angle is generally small, and such output wind sound can also be approximated as a straight wind field.

As shown in FIG. 4, the rotation speed of the first-stage impeller 2 is N1 and the rotation speed of the second-stage impeller 5 is N2. When N1 and N2 are not equal, the wind field formed by the counter-rotating fan 100 is a ring with a diffusion cone angle Vortex wind field. Due to a certain diffusion cone angle, the wind output range of the counter-rotating fan 100 is large, and the wind output is relatively soft. Although the air supply distance is short, the convection effect of the air flow is better than the wind field output by the traditional fan. Specifically, as shown in FIG. 6, assuming that the diffusion cone angle of the annular vortex wind field generated when a single impeller rotates is A00, when 1.6≥N1 / N2> 1, the ring generated by the counter-rotating impeller of the embodiment of the present invention The diffusion cone angle of the vortex wind field is 0≤A03≤1.3 * A00; when 0.2≤N1 / N2 <1, the diffusion cone angle of the wind field generated by the contra-rotating impeller of the embodiment of the present invention is 0.8 * A00≤A03≤2 * A00, when 0 <N1 / N2≤0.2, the diffusion cone angle of the wind field generated by the counter-impeller in the embodiment of the present invention is approximately equal to A00.

In summary, the counter-rotating fan 100 of the embodiment of the present invention can obtain an adjustable and controllable wind field by adjusting the rotational speed difference between the first-stage impeller 2 and the second-stage impeller 5, so that the counter-rotating fan 100 can generate both Conventional fan rotating circular volume air supply wind field can also produce a differentiated air supply wind field with straight beam focusing.

As a result, the wind energy of the counter-rotating fan 100 can be adjusted to a wide-angle divergent soft wind, a flat straight beam strong wind, or an arbitrary wind between the wide-angle divergent soft wind and the straight beam strong wind. It should be noted here that the diffuse angle of the wide-angle soft wind is larger, and the wind is softer. It is suitable for occasions where the air convection is slow. The spread angle of the straight beam-shaped strong wind is small, the wind pressure of the outflow is large, and the air supply distance is long, which is suitable for occasions where the convection speed is relatively fast. In addition, the arbitrary wind between the two mentioned above means that the spread angle is between the wide-angle diffuse soft wind and the straight bundle-shaped strong wind, and the wind pressure of the outgoing wind is also located between the two outgoing winds.

In some embodiments, the first-stage impeller 2 and the second-stage impeller 5 form a wind wheel group, and the counter-rotating fan 100 includes a plurality of wind wheel groups distributed at intervals in the axial direction. In this way, multiple wind wheel groups are combined to form more wind field types. The counter-rotating fan 100 including multiple wind wheel groups can better adapt to various airflow convection requirements, thereby improving customer satisfaction of the counter-rotating fan 100.

In some embodiments, the blade shape of the first blade 21 and the blade shape of the second blade 51 may be the same. In other embodiments, the blade shape of the first blade 21 and the blade shape of the second blade 51 may be different. It can be understood that the different blade shapes of the first blade 21 and the second blade 51 can increase the types of the wind field of the counter-rotating fan 100, so that the counter-rotating fan 100 can better meet the needs of use.

The rim diameter of the first blade 21 may be equal to the rim diameter of the second blade 51, and the rim diameter of the first blade 21 may not be equal to the rim diameter of the second blade 51. In both cases, the counter-rotating fan 100 can obtain a wind field with high wind pressure, large flow rate, long distance, and strong power as required.

The counter-rotating fan 100 according to a specific embodiment of the present invention will be described below with reference to FIGS. 1-12.

Example 1:

The counter-rotating fan 100 of the embodiment of the present invention includes an intake grille 1, a first-stage impeller 2, a first drive assembly 3, a motor bracket 4, a second-stage impeller 5, a second drive assembly 6, an outlet grille 7, a The first-level air guide ring 8 and the second-level air guide ring 9. The first-stage impeller 2 includes five circumferentially spaced first blades 21, the second-stage impeller 5 includes five circumferentially spaced second blades 51, the pressure surface Ps of the first blade 21 and the second blade 51 The suction surfaces Ss are oppositely arranged, and the bending directions of the first blade 21 and the second blade 51 are opposite.

This embodiment is a counter-rotating fan 100 with a casing diameter of 200 mm. The PIV axial plane velocity field test result of the two-stage impeller rotating at the same speed is shown in FIG. 7; the PIV axial plane velocity field test result of the two-stage impeller speed ratio greater than 1 As shown in Figure 8; PIV axial plane velocity field test results of two-stage impeller speed ratio <1 are shown in Figure 9.

It should be noted here that in FIGS. 7-9, the X-axis direction is the axial direction of the counter-rotating fan 100 and the Y-axis direction is the radial direction of the counter-rotating fan 100. As shown in FIG. 7, when the two-stage impeller rotates at the same speed, the air flow is basically kept horizontal in the positive direction of X. At this time, the output of the counter-rotating fan 100 is a straight wind field. This wind field has a long air supply distance. The pressure is greater. As shown in FIG. 8, when the rotation speed ratio of the two-stage impeller is greater than 1, the airflow has a significant deviation in the positive direction of X. At this time, the wind field output by the counter-rotating fan 100 has a certain diffusion angle. Closer, but the wind is softer. As shown in Figure 9, when the speed ratio of the two-stage impeller is less than 1, the airflow has a rotating vortex ring near the counter-rotating fan. This kind of wind field has a shorter air supply distance and softer wind output, which is very suitable. In some occasions where the airflow convection speed is relatively low.

For example, when the indoor air conditioner is just turned on, the two-stage impeller can be set to rotate at the same speed, so that the counter fan 100 has a long air supply distance, which can enhance the air supply function of the air conditioner, and the hot or cold air blown from the air conditioner can be blown into every corner of the room To accelerate indoor air convection. When the number of indoor personnel is large, the speed ratio of the two-stage impeller can be adjusted to be greater than 1, so that the area of the air supply is increased and the comfort is improved. When the user wants to enter the rest state, the speed ratio of the two-stage impeller can be adjusted to less than 1, so that it is not easy to catch a cold when used in the sleeping state.

In summary, the user can adjust the rotation speeds of the first-stage impeller 2 and the second-stage impeller to realize that the counter-rotating fan 100 outputs different wind fields to adapt to different use occasions, and the practicality of the counter-rotating fan 100 is further improved. .

Assuming that the diffusion cone angle of the annular vortex wind field generated when a single impeller rotates is A00, when 1.6≥N1 / N2> 1, the diffusion cone angle of the annular vortex wind field generated by the counter-rotating impeller of this embodiment is 0≤A03 ≤1.3 * A00; when 0.2≤N1 / N2 <1, the diffusion cone angle of the wind field generated by the counter-impeller in this embodiment is 0.8 * A00≤A03≤2 * A00, when 0 <N1 / N2≤0.2, this The diffusion cone angle of the wind field generated by the counter impeller in the embodiment of the invention is approximately equal to A00.

As shown in FIG. 10, the inlet angle of the first blade 21 is W1, the outlet angle of the first blade 21 is W2, the inlet angle of the second blade 51 is W3, and the outlet angle of the second blade 51 is W4, and W1 and W4 satisfy Relational formula: W1-10 ° ≤W4≤W1 + 10 °, W3t-5 ° ≤W3≤W3t + 5 °, W2 = W3, where: W3t = arctan {Fi * tan (W1) / [Fi + tan (W1 )]}, Fi is the flow coefficient. The axial width of the first blade 21 is B1, and the axial width of the second blade 51 is B2. B1 and B2 satisfy the relationship: B1 = 1.4 * B2. The axial direction between the first blade 21 and the second blade 51 is the smallest The gap Bg = 30 mm. The hub diameter D1 of the first-stage impeller 2 is equal to the hub diameter D2 of the second-stage impeller 5. The rim diameter of the first-stage impeller 2 is D01 equal to the rim diameter of the second-stage impeller 5 D02. The two edges of the first blade 21 in the circumferential direction are the first leading edge LE1 and the first trailing edge TE1 respectively, and the center angle between the blade tip and the root end of the first leading edge LE1 is W5, and the first tail The central angle between the tip of the leaf TE1 and the root of the leaf is W6. The two edges of the second blade 51 in the circumferential direction are the second leading edge LE2 and the second trailing edge TE2, respectively. The center angle between the blade tip and the root end of the second leading edge LE2 is W7, and the second tail The central angle between the leaf tip and the root end of the edge TE2 is W8. W5, W6, W7, W8 satisfy the relationship: W6 = 2W5, W8 = 2W7, W5 = W7 = 20 °.

Example 2

The structure of the counter-rotating fan 100 of this embodiment is substantially the same as that of Embodiment 1, and only the different features of Embodiment 2 and Embodiment 1 are described below. This embodiment is a counter-rotating fan 100 with a housing diameter of 200 mm. When 1.3≥N1 / N2> 1, the diffusion cone angle of the annular vortex wind field generated by the counter-rotating impeller of this embodiment is 0≤A03≤1.2 * A00; When 0.2 ≦ N1 / N2 <1, the diffusion cone angle of the wind field generated by the counter-rotating impeller of this embodiment is 0.8 * A00 ≦ A03 ≦ 2 * A00.

In this embodiment, W4 = W1, B1 = B2, Bg = 15mm, D01 = D02, D1 = D2, BN1 = 9, BN2 = 7, and the experiment curve of noise changes with the distance Bg of the two blades is shown in FIG. 14.

In the description of this specification, reference to the descriptions of the terms "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" is meant to be combined with the implementation The specific features, structures, materials, or characteristics described in the examples or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic expression of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art may understand that various changes, modifications, replacements, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, The scope of the invention is defined by the claims and their equivalents.

Claims (16)

1. A counter-rotating fan is characterized in that it includes a first-stage impeller and a second-stage impeller in opposite rotation directions, and the first-stage impeller and the second-stage impeller are driven by two mutually independent driving mechanisms. The first stage impeller includes a plurality of circumferentially spaced first blades, the second stage impeller includes a plurality of circumferentially spaced second blades, the pressure surface of the first blade and the suction force of the second blade The surfaces are arranged oppositely, and the bending directions of the first blade and the second blade are opposite.
2. The counter-rotating fan according to claim 1, wherein the angle between the inlet angle of the second blade and the reference angle of the first blade does not exceed 5 °, wherein the angle of the reference angle of the first blade It is calculated according to the speed triangle that the angle and the flow coefficient of the inlet angle of the first blade are two parameters of the speed triangle.
3. The counter-rotating fan according to claim 2, wherein the angle between the outlet angle of the second blade and the inlet angle of the first blade does not exceed 10 °, and the reference angle of the first blade The tangent value is positively correlated with the first variable, the tangent value of the first blade reference angle is negatively correlated with the second variable, the first variable is the tangent value of the flow coefficient and the first blade inlet angle The second variable is the sum of the flow coefficient and the tangent of the inlet angle of the first blade.
4. The counter-rotating fan according to claim 1, wherein the angle between the outlet angle of the second blade and the inlet angle of the first blade does not exceed 10 °, and the inlet angle of the second blade The angle between the reference angle of the first blade does not exceed 5 °, the inlet angle of the first blade is W1, the reference angle of the first blade is W3t, and W1 and W3t satisfy the relationship: W3t = arctan {Fi * tan (W1) / [Fi + tan (W1)]}, Fi is the flow coefficient.
5. The counter-rotating fan according to any one of claims 1 to 4, wherein the axial width of the first blade is at least 0.9 times the axial width of the second blade, and the first blade The axial width of does not exceed 1.5 times the axial width of the second blade.
6. The counter-rotating fan according to any one of claims 1 to 5, wherein the minimum axial gap between the first blade and the second blade is at least the axial direction of the first blade 0.1 times the width, and not more than 0.8 times the axial width of the first blade.
7. The counter-rotating fan according to any one of claims 1 to 6, wherein the diameter of the hub of the first-stage impeller is at least 0.8 times the diameter of the hub of the second-stage impeller. The diameter of the hub of the impeller does not exceed 1.1 times the diameter of the hub of the second-stage impeller.
8. The counter-rotating fan according to any one of claims 1-7, wherein the diameter of the rim of the first-stage impeller is at least 0.9 times the diameter of the rim of the second-stage impeller. The diameter of the rim of the first-stage impeller does not exceed 1.2 times the diameter of the rim of the second-stage impeller.
9. The counter-rotating fan according to any one of claims 1 to 8, wherein the two edges of the first blade in the circumferential direction are a first leading edge and a first trailing edge, respectively. The central angle between the tip of the leaf and the root end of the trailing edge is at least 1.5 times the central angle between the tip of the leaf and the root end of the first leading edge. The central angle between the root ends does not exceed 2.2 times the central angle between the tip of the leaves and the root end of the first leading edge.
10. The counter-rotating fan according to any one of claims 1-9, characterized in that the edges on both sides of the second blade in the circumferential direction are a second leading edge and a second trailing edge, respectively. The central angle between the leaf tip and the root end of the second trailing edge is at least 1.4 times the central angle between the leaf tip and the root end of the second leading edge, and the leaf tip and the leaf of the second trailing edge The central angle between the root ends does not exceed 2.1 times the central angle between the tip of the leaf and the root end of the second leading edge.
11. The counter-rotating fan according to any one of claims 1-10, wherein the number of the first blades is less than the number of the second blades, or the number of the first blades is greater than the number Number of second leaves;

    When the number of the first blades is less than the number of the second blades, the difference between the number of the second blades and the first blades does not exceed 2;

    When the number of the first blades is greater than the number of the second blades, the number of the first blades will not exceed twice the number of the second blades.
12. The counter-rotating fan according to any one of claims 1-11, wherein the rotation speed of the first-stage impeller is equal to the rotation speed of the second-stage impeller, so that the wind formed by the counter-rotating fan The field is a straight wind field.
13. The counter-rotating fan according to any one of claims 1 to 11, wherein the rotation speed of the first-stage impeller is not equal to the rotation speed of the second-stage impeller, so that the counter-rotating fan forms The wind field is an annular vortex wind field with a diffusion cone angle.
14. The counter-rotating fan according to any one of claims 1 to 11, wherein the first-stage impeller and the second-stage impeller form a wind wheel group, and the counter-rotating fan includes axially distributed A plurality of the wind wheel groups.
15. The counter-rotating fan according to claims 1-11, wherein the blade shape of the first blade and the blade shape of the second blade are different.
16. The counter-rotating fan according to claims 1-11, wherein the rim diameter of the first blade is equal to the rim diameter of the second blade, or the rim diameter of the first blade is not equal to The rim diameter of the second blade.

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