Cross-flow fan blade, Air conditioner

Abstract

The application provides a cross-flow fan blade and an air conditioner. The cross-flow fan blade comprises a plurality of blades which are arranged at intervals around the rotation axis of the cross-flow fan blade. The blade has a blade center line which is a circular arc line in the cross section of the blade. The thickness of the blade gradually increases and then gradually decreases from the middle position of the blade center line to the end position. According to the application, the thickness of the blade has two processes of increasing and decreasing in the flow path of the airflow, namely, the back curve and the basin curve of the blade have two processes of increasing and decreasing in thickness, respectively. The thickness of the blade forms a double-hump distribution in the flow path of the airflow instead of a single thickness increase in the prior art. Therefore, the airflow can effectively reduce the degree of airflow separation on the inflow side and the outflow side, especially reduce the separation loss of the airflow when the airflow enters and exits the flow channel twice, and effectively reduce the airflow flow loss of the fan and the power consumption of the indoor unit.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of air conditioning, and particularly relates to a cross-flow fan blade and an air conditioner. BACKGROUND

[0002] The cross-flow fan blade is widely used in the existing split air conditioner indoor unit. When the cross-flow fan blade rotates, the air flow enters and exits between the cross-flow fan blade blades twice. The air flow first passes through the blade from the outside to the inside of the cross-flow fan blade at the inlet side of the fan blade, and then passes through the blade from the inside to the outside of the cross-flow fan blade at the outlet side of the fan blade. Therefore, the cross-flow fan blade has both inlet and outlet sides. The surface of the blade of the existing cross-flow fan blade is designed as a smooth curved surface. The blade has a single circular arc design. The blade is composed of an outer end circular arc, an inner end circular arc, a back surface circular arc, and a basin surface circular arc. The maximum thickness of the cross-flow fan blade is located at the middle of the blade. The maximum thickness is d1, that is, the thickness of the blade is small at both ends and large in the middle. Research shows that the traditional blade with large thickness in the middle and small thickness at both ends has a serious air flow separation when the air flow enters or exits the cross-flow fan blade. This separation phenomenon causes flow loss, increases the power consumption of the indoor unit, and also causes noise problems of the indoor unit. In order to overcome the above-mentioned deficiencies, the applicant moves the maximum thickness of the traditional blade from the middle of the blade to the outer end of the blade. In this way, the separation degree of the air flow after passing through the traditional cross-flow fan blade can be reduced to a certain extent, and the flow loss and the power consumption of the indoor unit can be reduced. However, the separation degree of the air flow from the outlet side of the cross-flow fan, and the flow loss caused by the cross-flow fan blade still have room for further reduction. SUMMARY

[0003] Therefore, the present application provides a cross-flow fan blade and an air conditioner, which can overcome the deficiencies of the related art that the blade design of the cross-flow fan blade does not consider reducing the air flow separation degree at the air inlet side and the air outlet side, and the fan air flow loss and the power consumption of the indoor unit are large.

[0004] In order to solve the above-mentioned problems, the present application provides a cross-flow fan blade, which comprises a plurality of blades. The plurality of blades are arranged at intervals around the rotation axis of the cross-flow fan blade. The blade has a blade center line. In the cross-sectional view of the blade, the blade center line is a circular arc line. The thickness of the blade gradually increases from the middle position of the blade center line to the both ends.

[0005] In some embodiments, the blade has an outer end and an inner end. The minimum thickness of the blade at the middle position is dmin. The blade between the middle position and the outer end has a first maximum thickness dmax1. The blade between the middle position and the inner end has a second maximum thickness dmax2. dmin < dmax2 < dmax1.

[0006] In some embodiments, the outer end is formed by an outer end circular arc with a radius of do, the inner end is formed by an inner end circular arc with a radius of di, and dmin is not less than the smaller one of do and di.

[0007] In some embodiments, a line segment between the center of the outer end circular arc and the center of the blade midline is a first line segment, a line segment between the center of the inner end circular arc and the center of the blade midline is a second line segment, an included angle between the first line segment and the second line segment is θ, a line segment between the intersection of the straight line where the first maximum thickness is located and the blade midline and the center of the blade midline is a third line segment, and an included angle between the third line segment and the first line segment is α, θ / 5 < α < θ / 3.

[0008] In some embodiments, a line segment between the intersection of the straight line where the minimum thickness dmin at the intermediate position is located and the blade midline and the center of the blade midline is a fourth line segment, and an included angle between the fourth line segment and the first line segment is φ, θ / 2 < φ < 3θ / 4.

[0009] In some embodiments, a line segment between the intersection of the straight line where the second maximum thickness is located and the blade midline and the center of the blade midline is a fifth line segment, and an included angle between the fifth line segment and the first line segment is β, 2θ / 3 < β < 4θ / 5.

[0010] In some embodiments, on the cross section of the blade, a suction curve and a pressure curve are respectively connected between the outer end circular arc and the inner end circular arc, and the suction curve and the pressure curve are respectively smooth transition curves.

[0011] The application also provides an air conditioner, which comprises the cross-flow fan blade.

[0012] The cross-flow fan blade and the air conditioner provided by the application have two thickness increasing and decreasing processes on the flow path of the airflow, i.e., the suction curve and the pressure curve of the blade have two thickness increasing and decreasing processes, so that the thickness of the blade forms a double-hump distribution on the flow path of the airflow instead of a single thickness increase in the prior art. Therefore, the degree of airflow separation can be effectively reduced on the inflow side and the outflow side, especially the separation loss of the airflow when the airflow enters and exits the flow channel twice can be reduced, thereby effectively reducing the airflow flow loss of the fan and the power consumption of the indoor unit, and further reducing the airflow noise. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 FIG. 1 is a cross-sectional structure (radial cross section) of a cross-flow fan blade according to an embodiment of the application;

[0014] Figure 2 is a structural schematic view of the blade in the prior art; Figure 1

[0015] Figure 3a is a cloud picture of the air flow separation of the blade inlet and outlet side in the prior art;

[0016] Figure 3b is a cloud picture of the air flow separation of the blade inlet side in the prior art; Figure 3a

[0017] Figure 4 is a cloud picture of the air flow separation of the blade inlet and outlet side in the prior art;

[0018] Figure 5 is a comparison of the thickness distribution of the blade in the present application and the blade in the prior art on the blade center line;

[0019] Figure 6 is a comparison of the relative velocity of each position point on the outer diameter of the impeller of the cross-flow fan in the present application and the cross-flow fan in the prior art;

[0020] Figure 7 is a comparison of the air flow noise test of the cross-flow fan in the present application and the cross-flow fan in the prior art.

[0021] The reference signs are as follows:

[0022] 1, blade; 11, blade center line; 12, outer end; 13, inner end; 14, blade back curve; 15, blade basin curve; 2, plate body. DETAILED DESCRIPTION

[0023] For reference Figures 1 to 7 ​​As shown, according to the embodiment of the present application, a cross-flow fan blade is provided, which comprises a plurality of blades 1 arranged at intervals around the rotation axis of the cross-flow fan blade. In general, the intervals of two circumferentially adjacent blades 1 are uniform. The corresponding end portions of the plurality of blades 1 are connected to a plate body 2, which can be a partition plate or an end baffle, for example. The blade 1 has a blade midline 11, which is a circular arc line on the cross section of the blade 1 (which can also be understood as on the projection plane formed by the axial projection of the cross-flow fan blade). The thickness of the blade 1 gradually increases and then gradually decreases from the middle position of the blade midline 11 to the end positions. In this technical solution, the thickness of the blade 1 has two processes of increasing and decreasing in the flow path of the airflow, that is, the blade back curve 14 and the blade basin curve 15 of the blade 1 respectively have two processes of increasing and decreasing in thickness, so that the thickness of the blade 1 forms a double hump-shaped distribution in the flow path of the airflow instead of a single thickness increase in the prior art. In this way, the degree of airflow separation can be effectively reduced on both the inflow side and the outflow side, especially the separation loss of the airflow when the airflow enters and exits the flow passage twice can be reduced, thereby effectively reducing the airflow flow loss of the fan and the power consumption of the indoor unit, and in addition, the airflow noise can be further reduced.

[0024] It should be noted that the blade midline 11 is the connecting line of the midpoints of the thicknesses of the blade 1 at different positions from the inner end to the outer end thereof. When the blade midline 11 is a circular arc line, that is, the curvature radius thereof is single, the blade back curve 14 and the blade basin curve 15 respectively have two processes of increasing and decreasing in thickness.

[0025] Referring to Figure 2 As shown, the blade 1 has an outer end 12 and an inner end 13. The minimum thickness of the blade 1 at the middle position is dmin. The blade 1 between the middle position and the outer end 12 has a first maximum thickness dmax1. The blade 1 between the middle position and the inner end 13 has a second maximum thickness dmax2. dmin < dmax2 < dmax1, that is, in the design of the blade thickness being relatively high in front of the blade leading edge and low behind the blade leading edge, the degree of airflow separation of the inflow side airflow of the cross-flow fan can be further reduced while the degree of airflow separation of the outflow side airflow of the cross-flow fan is also reduced.

[0026] The outer end 12 is formed by an outer end circular arc, and the radius of the outer end circular arc is do. The inner end 13 is formed by an inner end circular arc, and the radius of the inner end circular arc is di. dmin is not less than the smaller one of do and di, so as to ensure the overall structural strength of the blade 1.

[0027] In some embodiments, the line connecting the center of the outer end arc and the center of the blade midline 11 is a first line segment, the line connecting the center of the inner end arc and the center of the blade midline 11 is a second line segment, the included angle between the first line segment and the second line segment is θ, the line connecting the intersection point of the straight line where the first maximum thickness is located and the blade midline 11 and the center of the blade midline 11 is a third line segment, the included angle between the third line segment and the first line segment is α, θ / 5 < α < θ / 3; further, the line connecting the intersection point of the straight line where the minimum thickness dmin at the middle position is located and the blade midline 11 and the center of the blade midline 11 is a fourth line segment, the included angle between the fourth line segment and the first line segment is φ, θ / 2 < φ < 3θ / 4; further, the line connecting the intersection point of the straight line where the second maximum thickness is located and the blade midline 11 and the center of the blade midline 11 is a fifth line segment, the included angle between the fifth line segment and the first line segment is β, 2θ / 3 < β < 4θ / 5, and thus α < φ < β. It can be understood that the intersection points of the aforementioned straight lines where the thicknesses are located and the blade midline 11 are described based on the view of the same cross section, which is specifically the cross section shown in Figure 2 The aforementioned angles are used to control the positions corresponding to the respective blade thicknesses, the first thickness is close to the front side of the midline, the second thickness is close to the rear side beyond 2 / 3 of the blade, and the minimum thickness at the middle position is close to the rear side.

[0028] In some embodiments, on the cross section of the blade 1, the outer end arc and the inner end arc are respectively connected with a blade back curve 14 and a blade basin curve 15, the blade back curve 14 and the blade basin curve 15 are respectively smooth transition curves, which reduce the airflow loss caused by the contact between the airflow and the blade 1. Specifically, referring to Figure 5 The blade in the present application presents a thickness increasing and decreasing process with both sides smooth along the blade midline from the outer end to the inner end of the blade 1, forming a double hump structure.

[0029] In a specific embodiment, the design parameters of the blade 1 are as follows: dmax1 = 1.066 mm, dmax2 = 0.836 mm, dmin = 0.828 mm, θ = 69°, α = 18°, Φ = 39°, β = 53°, the cross-flow fan blade of the present application is designed and produced in three dimensions, and the processed cross-flow fan blade is installed on an air conditioner indoor unit for experimental testing, and the comparison of the actual measurement results is shown in Figure 7 Under the condition that the air volume is basically the same, the fan blade of the present application can reduce the noise of the indoor unit by 1-2 dBA compared with the existing fan blade. As shown in Figure 6 As shown in

[0030] According to the embodiment of the present application, an air conditioner is also provided, which is characterized by comprising the cross-flow fan blade.

[0031] Those skilled in the art will readily understand that the above-mentioned advantageous modes can be freely combined and superimposed without conflict.

[0032] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application. The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cross-flow impeller comprising a plurality of blades (1) which are arranged at intervals around an axis of rotation of the cross-flow impeller, the blades (1) having a blade midline (11), characterized in that, In the cross section of the blade (1), the blade midline (11) is a circular arc line, the thickness of the blade (1) gradually increases and then gradually decreases from the middle position of the blade midline (11) to the end position; the blade (1) has an outer end (12) and an inner end (13); the outer end (12) is formed by an outer end circular arc, and the inner end (13) is formed by an inner end circular arc; the connecting line between the center of the outer end circular arc and the center of the blade midline (11) is a first line segment, the connecting line between the center of the inner end circular arc and the center of the blade midline (11) is a second line segment, the included angle between the first line segment and the second line segment is θ, the connecting line between the intersection of the straight line where the minimum thickness dmin of the middle position is located and the center of the blade midline (11) is a fourth line segment, and the included angle between the fourth line segment and the first line segment is φ, θ / 2<φ<3θ / 4.

2. The cross-flow impeller of claim 1, wherein, The minimum thickness of the blade (1) at the middle position is dmin, the blade (1) between the middle position and the outer end (12) has a first maximum thickness dmax1, the blade (1) between the middle position and the inner end (13) has a second maximum thickness dmax2, dmin 3. The cross-flow impeller of claim 2, wherein, The radius of the outer end circular arc is do, the radius of the inner end circular arc is di, and dmin is not less than the smaller one of do and di.

4. The cross-flow impeller of claim 3, wherein, The connecting line between the intersection of the straight line where the first maximum thickness is located and the center of the blade midline (11) is a third line segment, the included angle between the third line segment and the first line segment is α, θ / 5<α<θ / 3.

5. The cross-flow impeller of claim 2, wherein, The connecting line between the intersection of the straight line where the second maximum thickness is located and the center of the blade midline (11) is a fifth line segment, the included angle between the fifth line segment and the first line segment is β, 2θ / 3<β<4θ / 5.

6. The cross-flow impeller of claim 1, wherein, In the cross section of the blade (1), the outer end circular arc and the inner end circular arc are respectively connected with a back curve (14) and a basin curve (15), and the back curve (14) and the basin curve (15) are respectively smooth transition curves.

7. An air conditioner characterized by comprising: The tubular fan blade comprises the tubular fan blade according to any one of claims 1 to 6.

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