Axial flow fan blade, outdoor unit and air conditioner

Abstract

The invention discloses an axial-flow fan blade, an outdoor unit and an air conditioner, and relates to the technical field of air conditioners, the axial-flow fan blade comprises a hub and a plurality of blades arranged on the periphery of the hub at intervals, and the outer edges of the blades are folded in the direction from the pressure faces to the suction faces to form blade winglets; and the blade winglet is arranged close to one end of the tail edge of the blade. According to the technical scheme provided by the invention, the blade tip vortex intensity of the axial flow fan blade is reduced, and the use comfort of the air conditioner is improved.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to an axial flow fan blade, an outdoor unit, and an air conditioner. Background Technology

[0002] In the outdoor unit of an air conditioner, the axial fan is a crucial component for heat dissipation and air supply. A certain clearance exists between the blade tip and the casing of the axial fan. Due to this clearance, when the axial fan is operating, some fluid on the pressure surface of the blades overflows the clearance under the influence of pressure difference, forming a tip leakage flow. The tip leakage vortex formed by this tip leakage is a significant source of aerodynamic noise from the axial fan blades.

[0003] Currently, blade winglets are commonly used to reduce leakage flow at the blade tip. On the blade, the winglets begin at the leading edge and terminate at the trailing edge. However, experimental testing has shown that this design still results in strong vortex intensity at the blade tip, leading to higher noise levels in the air conditioner. Summary of the Invention

[0004] The main objective of this invention is to provide an axial flow fan blade, an outdoor unit, and an air conditioner, which aims to reduce the tip vortex intensity of the axial flow fan blade and improve the user comfort of the air conditioner.

[0005] To achieve the above objectives, the present invention proposes an axial flow fan blade comprising:

[0006] Wheel hubs; and

[0007] Multiple blades are spaced apart on the outer periphery of the hub; the outer edge of each blade is folded in the direction from the pressure surface to the suction surface to form a blade winglet, and the blade winglet is located at one end near the trailing edge of the blade.

[0008] In one embodiment, the length L1 of the blade airfoil along the circumferential direction of the outer edge of the blade is:

[0009] L1=(0.62~0.72)*(L0 / S)*L0;

[0010] Where L0 is the total chord length of the outer edge of the blade, and S is the spacing between the blades;

[0011] S = 2πR / n, where R is the outer diameter of the blade and n is the number of blades.

[0012] In one embodiment, the blade winglet has a tail notch section near the trailing edge of the blade, and an avoidance notch is formed between the tail notch section and the trailing edge of the blade.

[0013] In one embodiment, the blade winglet has a height in the direction from the pressure surface to the suction surface, and the height of the tail notch section ranges from 0 mm to 1 mm; and / or

[0014] Along the circumference of the blade, the length of the tail notch section is 0mm-6mm.

[0015] In one embodiment, in the direction from the leading edge to the trailing edge of the blade, the blade winglet includes a starting section with gradually increasing height, a contour section with uniform height, and a tail notch section. The height of the end of the starting section away from the contour section is 0, and the height of the end of the starting section close to the contour section is the same as the height of the contour section.

[0016] In one embodiment, the height of the contour section is H, where 4mm ≤ H ≤ 0.045R, and R is the outer diameter of the blade.

[0017] In one embodiment, the outward tilt angle α of the blade airfoil is 6°-18°.

[0018] In one embodiment, the radius of the transition fillet between the blade winglet and the suction surface is R1, and the radius of the transition fillet between the blade winglet and the pressure surface is R2, where R1 = (4~6.5)R2.

[0019] In one embodiment, the blade winglet has a first surface for connecting with the suction surface and a second surface for connecting with the pressure surface, wherein the first surface and the second surface intersect at the end of the blade winglet away from the blade.

[0020] The present invention also proposes an outdoor unit, comprising:

[0021] The shell has a receiving cavity; and

[0022] An axial flow fan is installed in the receiving cavity, and the axial flow fan includes the axial flow fan blades.

[0023] In one embodiment, the outdoor unit further includes an air guide ring installed in the receiving cavity, the air guide ring being coaxially arranged with the axial flow fan, and at least a portion of the blade fins overlapping the air guide ring along the axial direction of the air guide ring.

[0024] In one embodiment, along the axial direction of the axial flow fan, the projected height of the blade winglet is H1, and the overlap height between the blade winglet and the air guide ring is H2, where H2 = (0.5~0.65)H1.

[0025] In one embodiment, the outdoor unit further includes a heat exchanger installed in the receiving cavity, the heat exchanger including a straight section located on one side of the suction surface of the fan blade; the projection of the free end of the straight section along the axial direction of the air guide ring is located within the air guide ring.

[0026] In one embodiment, the free end distance of the straight segment of the heat exchanger, the distance at the intersection of the extension line of the axis of the axial fan and the heat exchanger is D1, and the inner radius of the guide ring is R1, wherein 0.7R1≤D1≤1.02R1.

[0027] The present invention also proposes an air conditioner, characterized in that it includes the aforementioned outdoor unit and indoor unit.

[0028] The indoor unit and the outdoor unit are connected by a flexible refrigerant pipe, and the flexible refrigerant pipe is pre-charged with refrigerant; and / or, the compressor of the air conditioner is located in the indoor unit.

[0029] The technical solution of this invention involves arranging a hub and multiple blades mounted on the outer periphery of an axial flow fan. The outer edge of each blade is folded from the pressure surface towards the suction surface to form a blade winglet, which is located at the tip of the blade near the trailing edge. This achieves two advantages: firstly, by placing the blade winglet at the blade tip, the airflow between the suction and pressure surfaces of the blade is separated, controlling tip leakage. Secondly, because the leading edge of the blade is not covered by the guide ring and is in an open space, placing the blade winglet at the tip near the trailing edge avoids the increased pressure gradient and vortex intensity that would occur with blade winglets in such an open space, thus preventing additional noise. This improves the efficiency of the axial flow fan and enhances the user comfort of the air conditioner. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a structural embodiment of the axial flow fan blade provided by the present invention;

[0032] Figure 2 for Figure 1 A cross-sectional view of an embodiment at the contour section of the mid-blade airfoil;

[0033] Figure 3 This is a schematic diagram of the structure of an embodiment of the outdoor unit provided by the present invention;

[0034] Figure 4 for Figure 3 A cross-sectional view of an embodiment of the outdoor unit after part of the casing has been removed;

[0035] Figure 5 The results are CFD simulations of blade structures without blade winglets in existing technologies.

[0036] Figure 6 The results are CFD simulations of the present invention.

[0037] Figure 7 A comparison chart of air volume and power for outdoor units with different axial fan blades;

[0038] Figure 8 A graph comparing the airflow and noise levels of outdoor units equipped with different axial fan blades;

[0039] Figure 9 This is a comparison of the dirt clogging test results of the present invention with those of an outdoor unit without blade winglets.

[0040] Explanation of icon numbers:

[0041] 100. Axial flow fan blades; 200. Wheel hub;

[0042] 300. Blade; 311. Pressure surface; 312. Suction surface; 321. Leading edge; 322. Trailing edge; 323. Blade tip; 324. Blade root; 330. Blade winglet; 331. Initial section; 332. Contour section; 333. Tail notch section; 334. Avoidance notch; 335. First surface; 336. Second surface;

[0043] 400 Outdoor unit; 410 Housing; 411 Receiving cavity; 420 Axial flow fan; 421 Motor; 422 Motor bracket; 430 Air guide ring; 440 Heat exchanger; 441 Straight section; 450 Baffle plate.

[0044] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0047] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0048] In the outdoor unit of an air conditioner, the axial fan is a crucial component for heat dissipation and airflow. During high-speed operation, a certain gap, known as a clearance, exists between the blades and the casing to prevent friction and collision between the fan blades and the casing wall during relative motion. Due to this clearance, when the axial fan is operating, some fluid on the pressure surface of the blades overflows the clearance under the influence of pressure difference, forming a tip leakage flow. The tip leakage vortex formed by this flow is a significant source of aerodynamic noise in axial fan blades. Furthermore, the aerodynamic losses caused by the tip leakage flow account for approximately one-third of the overall aerodynamic losses in an axial fan.

[0049] Blade winglet technology, as one of the methods for passively controlling tip leakage flow, has been extensively researched and applied in other turbomachinery fields. That is, a blade winglet is installed at the blade tip, folding towards the suction surface. Typically, the blade winglet begins at the leading edge of the blade and terminates at the trailing edge. However, experimental verification has shown that this blade winglet structure still suffers from strong vortex intensity at the blade tip, resulting in relatively high noise levels in air conditioners.

[0050] This invention proposes an axial flow fan blade 100.

[0051] Please see Figure 1In one embodiment of the present invention, the axial flow fan blade 100 includes a hub 200 and a plurality of blades 300, the plurality of blades 300 being spaced apart on the outer periphery of the hub 200; the outer edge of the blade 300 is folded in the direction from the pressure surface 311 toward the suction surface 312 to form a blade winglet 330, the blade winglet 330 being disposed at one end near the trailing edge 322 of the blade 300.

[0052] Specifically, the hub 200 is located at the center of the axial flow fan blade 100. The hub 200 is cylindrical, and multiple blades 300 are evenly spaced along the circumference of the hub 200. In one embodiment, the number of blades 300 ranges from 3 to 6. The axial direction of the hub 200 is also the axial direction of the axial flow fan blade 100. Along the axial direction of the axial flow fan blade 100, the blade 300 includes two opposing surfaces, namely a pressure surface 311 and a suction surface 312. The pressure surface 311 refers to the surface of the blade 300 that is closer to the outlet side when the axial flow fan 420 is operating, while the suction surface 312 is the surface that is closer to the inlet side. The end of the blade 300 connected to the hub 200 is the blade root 324, the end of the blade 300 away from the hub 200 is the blade tip 323, the foremost windward part of the blade 300 is the leading edge 321, and the outlet part is the trailing edge 322.

[0053] The blade tip 323 of blade 300 is folded towards the suction surface 312 to form a blade winglet 330, which is smoothly connected to the blade tip 323. Understandably, the axial fan 420, equipped with the axial fan blade 100, works in conjunction with the guide ring 430 to draw air from one end of the guide ring 430 to the other, forming an airflow. When the axial fan 420 rotates, the folded blade winglet 330 can separate the airflow between the suction surface 312 and the pressure surface 311 of blade 300.

[0054] For the outdoor unit 400 of the air conditioner, along the axial direction of the axial fan 420, the portion of the blades 300 near the leading edge 321 cannot be completely covered by the guide ring 430 (e.g., Figure 4 As shown, the portion of the blade tip 323 near the leading edge 321 is in an open space, and a strong pressure gradient does not form between the suction surface 312 and the pressure surface 311. Therefore, the tip vortex intensity of the portion of the blade tip 323 near the leading edge 321 of the blade 300 is not high. In this case, if a blade winglet 330 extending from the leading edge 321 to the trailing edge 322 is provided on the blade tip 323, it would instead lead to an increase in pressure gradient and vortex intensity, creating an additional noise source and causing a decrease in the efficiency of the axial flow fan 420. In this invention, the blade winglet 330 is located at the end of the blade tip 323 near the trailing edge 322, that is, the blade winglet 330 is located in the rear half of the blade tip 323. This avoids the increase in pressure gradient and vortex intensity caused by the blade winglet 330 located at the leading edge 321 of the blade 300 being in an open space.

[0055] The technical solution of the present invention involves arranging a hub 200 and a plurality of blades 300 mounted on the outer periphery of the axial flow fan blade 100. The outer edge of the blades 300 is folded from the pressure surface 311 toward the suction surface 312 to form blade winglets 330, which are located at the tip 323 near the trailing edge 322. In this way, by providing blade winglets 330 at the tip 323 of the blades 300, the airflow between the suction surface 312 and the pressure surface 311 of the blades 300 is separated, thereby controlling leakage flow at the tip 323. On the other hand, since the leading edge 321 of the blade 300 is not covered by the guide ring 430 and is in an open space, the blade winglet 330 is set at the end of the blade tip 323 near the trailing edge 322. This avoids the pressure gradient and vortex intensity increase caused by setting the blade winglet 330 in an open space, thereby avoiding additional noise, which is conducive to improving the efficiency of the axial fan 420 and improving the comfort of using the air conditioner.

[0056] Please see Figure 1 In an embodiment of the present invention, the length L1 of the blade winglet 330 along the circumferential direction of the outer edge of the blade 300 is:

[0057] L1=(0.62~0.72)*(L0 / S)*L0;

[0058] Where L0 is the total chord length of the outer edge of blade 300, and S is the spacing between blades 300;

[0059] S = 2πR / n, where R is the outer diameter of blade 300 and n is the number of blades 300.

[0060] Specifically, the length L1 of the blade winglet 330 refers to the length of the blade winglet 330 extending circumferentially along the blade tip 323. In one embodiment, when the length of the blade winglet 330 satisfies a certain condition, namely L1 = (0.62~0.72)*(L0 / S)*L0, the blade winglet 330 can significantly control the leakage flow at the blade tip 323, reduce the intensity of the blade tip vortex, improve the efficiency of the axial flow fan blade 100, and reduce noise. Here, L0 is the total chord length of the outer edge of the blade 300, which is the length of the outer periphery of the blade tip 323. S is the spacing between multiple blades 300, and n is the number of blades 300, which can be any integer from 3 to 6.

[0061] Please see Figure 1 In an embodiment of the present invention, the blade winglet 330 is provided with a tail notch section 333 near the trailing edge 322 of the blade 300, and an avoidance notch 334 is formed between the tail notch section 333 and the trailing edge 322 of the blade 300.

[0062] Specifically, the blade winglet 330 has a clearance notch 334 near the trailing edge 322 of the blade 300. The clearance notch 334 avoids the formation of a stress concentration sharp corner between the blade winglet 330 and the trailing edge 322 of the blade 300, thereby preventing the axial flow fan blade 100 from being damaged during transportation, thus improving the protection of the axial flow fan blade 100 and increasing its service life.

[0063] In an embodiment of the invention, the blade winglet 330 has a height in the direction from the pressure surface 311 to the suction surface 312, and the height of the tail notch section 333 ranges from 0 mm to 1 mm; and / or, along the circumference of the blade 300, the length of the tail notch section 333 is 0 mm to 6 mm. This avoids the formation of a sharp angle of stress concentration between the blade winglet 330 and the trailing edge 322 of the blade 300, thereby preventing damage to the axial flow fan blade 100 during transportation.

[0064] Please see Figure 1 In an embodiment of the present invention, in the direction from the leading edge 321 of the blade 300 to the trailing edge of the blade 300, the blade winglet 330 includes a starting segment 331 with gradually increasing height, a contour segment 332 with consistent height, and a tail notch segment 333. The height of the end of the starting segment 331 away from the contour segment 332 is 0, and the height of the end of the starting segment 331 close to the contour segment 332 is consistent with the height of the contour segment 332.

[0065] Specifically, the blade winglet 330 is located on the rear half of the blade tip 323 near the trailing edge 322. The blade winglet 330 is configured with a connected starting section 331, a level section 332, and a tail notch section 333. The starting section 331 has a height of 0 at the end near the leading edge 321, and the end of the starting section 331 near the trailing edge 322 is connected to and has the same height as the level section 332. Understandably, when the axial flow fan 100 rotates, the starting section 331 of the blade winglet 330 faces the wind first, followed by the level section 332. Thus, by setting the starting section 331 to gradually increase in height, with the windward side of the starting section 331 having a height of 0, the wind resistance of the blade winglet 330 when facing the wind is reduced, which is beneficial for improving the efficiency of the axial flow fan 420.

[0066] Please see Figure 1 and Figure 2 In an embodiment of the present invention, the height of the contour section 332 is H, 4mm≤H≤0.045R, where R is the outer diameter of the blade 300.

[0067] Specifically, the blade winglet 330 has a certain height in the direction from the pressure surface 311 to the suction surface 312. The height of the equal-height section 332 is denoted by H. It can be understood that the equal-height section 332 refers to the portions of the blade winglet 330 with equal heights, where "equal heights" means approximately equal, not absolutely equal. Due to limitations such as molding processes, a certain height difference range is allowed for the equal-height section 332. In one embodiment, the height difference range of the equal-height section 332 is 0.5 mm. Here, the height difference range of the equal-height section 332 is not limited.

[0068] In one embodiment, when 4mm≤H≤0.045R, the blade winglet 330 can significantly control the leakage flow at the blade tip 323, reduce the intensity of the blade tip vortex, improve the efficiency of the axial fan blade 100, and reduce the operating noise of the air conditioner.

[0069] Please see Figure 2 In an embodiment of the present invention, the outward tilt angle α of the blade winglet 330 is 6°-18°.

[0070] Understandably, the outward cant angle α of the blade winglet 330 refers to the angle between the blade winglet 330 after it is folded and the normal at the tip 323 of the blade 300. In one embodiment of the present invention, the outward cant angle α of the blade winglet 330 is 6°-18°, which can achieve better vortex control and noise reduction, while improving the manufacturability of the blade 300 and the mold life.

[0071] Please see Figure 2 In an embodiment of the present invention, the radius of the transition fillet between the blade winglet 330 and the suction surface 312 is R1, and the radius of the transition fillet between the blade winglet 330 and the pressure surface 311 is R2, wherein R1 = (4~6.5)R2.

[0072] Understandably, the blade winglet 330 is smoothly connected to the blade 300. Along the radial direction of the axial flow fan blade 100, the blade winglet 330 has a side facing the hub 200 and a side facing away from the hub 200. The side of the blade winglet 330 facing the hub 200, which is the side where it connects to the suction surface 312, has a transition fillet radius of R1 between this side and the suction surface 312 of the blade 300. This transition fillet ensures a smooth connection between the blade winglet 330 and the suction surface 312. The side of the blade winglet 330 facing away from the hub 200, which is the side where it connects to the pressure surface 311, has a transition fillet radius of R2 between this side and the pressure surface 311 of the blade 300. This transition fillet ensures a smooth connection between the blade winglet 330 and the pressure surface 311. Wherein, Figure 2 sectional view direction and Figure 4The same applies. In one embodiment, R1 = (4~6.5)R2, so that the blade winglet 330 can significantly control the leakage flow at the blade tip 323, reduce the intensity of the blade tip vortex, improve the efficiency of the axial fan blade 100, and reduce the operating noise of the air conditioner.

[0073] Please see Figure 1 and Figure 2 In an embodiment of the present invention, the blade winglet 330 has a first surface 335 for connecting with the suction surface 312 and a second surface 336 for connecting with the pressure surface 311, and the first surface 335 and the second surface 336 intersect at the end of the blade winglet 330 away from the blade 300.

[0074] Understandably, along the radial direction of the axial fan blade 100, the blade winglet 330 has a first surface 335 and a second surface 336 arranged opposite to each other. The first surface 335 is located closer to the hub 200 and is used to connect with the suction surface 312; the second surface 336 is located away from the hub 200 and is used to connect with the pressure surface 311. Along the height direction of the blade winglet 330, the first surface 335 and the second surface 336 intersect at the top of the blade winglet 330. That is, the cross-section of the blade winglet 330 is approximately triangular. In other words, along the radial direction of the axial fan blade 100, the blade winglet 330 has a certain thickness, and the thickness of the blade winglet 330 gradually decreases from the pressure surface 311 to the suction surface 312. The blade winglet 330 is set at a sharp angle at the top, which helps to reduce the wind resistance of the blade winglet 330 and improve the efficiency of the axial fan 420.

[0075] Please see Figure 5 and Figure 6 Detailed CFE simulation experiments revealed that the blade winglet 330 structure in this invention can effectively control the tip leakage vortex loudness of the axial flow fan blade 100. At 90% of the blade's span, in existing blade structures without the blade winglet 330, the low-speed vortex intensity caused by tip leakage vortex is high, and the low-speed region extends to the center of the main flow channel, affecting duct efficiency. With the blade winglet 330 of this invention, the tip leakage vortex intensity at the same location is reduced, the low-speed region is suppressed, and flow efficiency is improved.

[0076] Please see Figure 3 and Figure 4The present invention also proposes an outdoor unit 400, which includes a housing 410 and an axial flow fan 420. The axial flow fan 420 includes an axial flow blade 100, the specific structure of which is as described in the above embodiments. Since the outdoor unit 400 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here. The housing 410 forms a receiving cavity 411, and the axial flow fan 420 is installed in the receiving cavity 411. The axial flow fan 420 includes an axial flow blade 100, a motor 421, and a motor bracket 422. The motor bracket 422 is installed in the housing 410, and the motor 421 is installed on the motor bracket 422. The motor 421 is connected to the hub 200 of the axial flow blade 100 for transmission, thereby driving the axial flow blade 100 to rotate.

[0077] Please see Figure 4 In an embodiment of the present invention, the outdoor unit 400 further includes an air guide ring 430 installed in the receiving cavity 411. The air guide ring 430 is coaxially arranged with the axial flow fan 420. Along the axial direction of the air guide ring 430, at least a portion of the blade winglets 330 overlap with the air guide ring 430.

[0078] Understandably, the air guide ring 430 is coaxially arranged with the axial flow fan 420, and the air guide ring 430 has the functions of guiding airflow, improving airflow distribution, reducing eddies, and adjusting air volume. In the outdoor unit 400, along the axial direction of the air guide ring 430, the air guide ring 430 cannot cover all of the axial flow fan blades 100. Therefore, in this invention, the blade fins 330 are provided on the portion of the blade tip 323 facing the trailing edge 322. In one embodiment, along the axial direction of the air guide ring 430, at least a portion of the blade fins 330 overlaps with the air guide ring 430. In this way, a blade tip 323 leakage vortex control structure is formed between the blade fins 330 and the air guide ring 430, thereby improving the pressure resistance of the blades 300 during operation.

[0079] Please see Figure 4 In an embodiment of the present invention, along the axial direction of the axial flow fan 420, the projected height of the blade winglet 330 is H1, and the overlap height between the blade winglet 330 and the guide ring 430 is H2, where H2 = (0.5~0.65)H1. This is beneficial for improving the efficiency of the axial flow fan 420 and reducing its noise.

[0080] Please see Figure 4 In an embodiment of the present invention, the outdoor unit 400 further includes a heat exchanger 440 installed in the receiving cavity 411. The heat exchanger 440 includes a straight section 441, which is located on one side of the suction surface 312 of the fan blade. The projection of the free end of the straight section 441 on the axial direction of the air guide ring 430 is located inside the air guide ring 430.

[0081] Specifically, in the outdoor unit 400, a heat exchanger 440 is used to absorb or release heat. In one embodiment, the heat exchanger 440 extends circumferentially along the housing 410 within the receiving cavity 411 and is distributed at least on two adjacent sidewalls of the housing 410 to increase the heat exchange area of ​​the heat exchanger 440 and improve heat exchange efficiency. The straight section 441 of the heat exchanger 440 is located on one side of the suction surface 312 of the fan blade, that is, at least a portion of the heat exchanger 440 is located on the air inlet side of the axial fan 420, which is used to accelerate the heat exchange efficiency of the heat exchanger 440. In one embodiment, the outdoor unit 400 also includes a partition 450 installed within the receiving cavity 411, the partition 450 being close to the free end of the heat exchanger 440, thereby positioning the axial fan 420 between the partition 450 and the heat exchanger 440. The heat exchanger 440, baffle 450, axial fan 420 and air guide ring 430 constitute a forced air-cooled heat exchange system. The baffle 450 is designed so that the air inlet side of the axial fan 420 can be drawn in from the heat exchanger 440 as much as possible to ensure heat exchange efficiency.

[0082] The heat exchanger 440 of the outdoor unit 400 is arranged asymmetrically. After installation, the projection of the free end of the straight section 441 on the axial direction of the air guide ring 430 is located inside the air guide ring 430. That is, the end of the straight section 441 of the heat exchanger 440 falls within the range of the air guide ring 430, thereby forming a gradually expanding air duct between the heat exchanger 440, the baffle 450 and the axial fan blade 100. This solves the problem of efficiency loss and noise of the axial fan 420 caused by the distortion of the inlet airflow due to the asymmetrical installation of the heat exchanger 440.

[0083] Please see Figure 4 In an embodiment of the present invention, the distance from the free end of the straight segment 441 of the heat exchanger 440 to the intersection of the extended line of the axis of the axial fan 420 and the heat exchanger 440 is D1, and the inner radius of the guide ring 430 is R1, wherein 0.7R1≤D1≤1.02R1. At this point, the axial fan 420 has higher efficiency and lower noise, and the heat exchanger 440 has better heat exchange efficiency.

[0084] Please see Figure 7 and Figure 8Experiments revealed that different blade structures resulted in varying performance test data for the outdoor unit 400. The figure shows three blade structures: the prototype without winglets refers to blade 300 without winglets 330; the 0° tilt angle + long chord long winglet refers to blade 300 with winglets 330 at the blade tip 323, starting at the leading edge 321 and ending at the trailing edge 322, with an outward tilt angle of 0°; this solution refers to the winglet 330 structure described in this invention. Compared to the prototype without winglets, adding winglets 330 significantly improves the system efficiency of the axial fan 420, reducing power consumption by 6-16% for the same airflow with different winglet 330 designs. However, improper shape and placement of the winglets 330 can significantly increase the noise of the blade 300 by 0.5-1.5 dBA. This invention optimizes the blade winglet 330 structure, ultimately achieving the beneficial effects of a 2.5 dBA reduction in noise and approximately 16% reduction in power compared to the prototype without winglets.

[0085] Please see Figure 9 Through simulated heat exchanger 440 clogging tests, it was found that after adopting the blade winglet 330 structure of this invention, the airflow attenuation was reduced by 11% compared to the prototype structure without winglets. This result indicates that this invention significantly improves the pressure resistance of the outdoor unit 400's air duct system. Comparative analysis in the overall heating test shows that, due to the improved air duct pressure resistance, the airflow attenuation during frosting is slower, and the heating and defrosting cycle is extended by approximately 2 hours, significantly improving the heating efficiency of the outdoor unit 400.

[0086] The present invention also proposes an air conditioner (not shown) comprising an outdoor unit 400 and an indoor unit (not shown). The specific structure of the outdoor unit 400 is as described in the above embodiments. Since this air conditioner adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated further here. The indoor unit and the outdoor unit 400 are connected by a flexible refrigerant pipe (not shown), and the flexible refrigerant pipe is pre-charged with refrigerant; and / or, the air conditioner's compressor is located in the indoor unit.

[0087] The air conditioner of this invention can be a split-type air conditioner that is easy for users to install individually. By placing the compressor assembly in the indoor unit, the weight of the outdoor unit 400 can be reduced, thereby facilitating the installation of the outdoor unit 400. Correspondingly, by placing the compressor assembly in the indoor unit, a noise reduction structure needs to be incorporated into the compressor to ensure the comfort and low noise interference of the air conditioner.

[0088] The air conditioner uses flexible refrigerant pipes to connect the indoor heat exchanger 440 of the indoor unit and the outdoor heat exchanger 440 of the outdoor unit 400, and refrigerant is injected into the refrigerant circuit before the equipment leaves the factory. Thus, when users install the equipment themselves, they only need to fix the indoor unit and outdoor unit 400 separately, without needing to install refrigerant pipes or add refrigerant, thereby reducing installation difficulty and enabling individual user installation.

[0089] However, this design is not limited to this. In other embodiments, the air conditioner of the present invention can also be a conventional split-type air conditioner. In one embodiment, a compressor is installed inside the outdoor unit 400. In one embodiment, the installation space for the compressor can be expanded by reducing the D1 dimension of the heat exchanger 440, thereby making the overall size of the outdoor unit 400 more compact.

[0090] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An axial flow fan blade, characterized in that, include: Wheel hub; as well as Multiple blades are spaced apart on the outer periphery of the hub; the outer edge of each blade is folded in the direction from the pressure surface to the suction surface to form a blade winglet, and the blade winglet is located at one end near the trailing edge of the blade.

2. The axial flow fan blade as described in claim 1, characterized in that, Along the circumferential direction of the outer edge of the blade, the length L1 of the blade airfoil is: L1=(0.62~0.72)*(L0 / S)*L0; Where L0 is the total chord length of the outer edge of the blade, and S is the spacing between the blades; S = 2πR / n, where R is the outer diameter of the blade and n is the number of blades.

3. The axial flow fan blade as described in claim 1, characterized in that, The blade winglet has a tail notch section near the trailing edge of the blade, and an avoidance notch is formed between the tail notch section and the trailing edge of the blade.

4. The axial flow fan blade as described in claim 3, characterized in that, The blade winglet has a height in the direction from the pressure surface to the suction surface, and the height of the tail notch section ranges from 0 mm to 1 mm; and / or Along the circumference of the blade, the length of the tail notch section is 0mm-6mm.

5. The axial flow fan blade as described in claim 3, characterized in that, In the direction from the leading edge to the trailing edge of the blade, the blade winglet includes an initial section with gradually increasing height, a contour section with uniform height, and a tail notch section. The height of the end of the initial section away from the contour section is 0, and the height of the end of the initial section close to the contour section is the same as the height of the contour section.

6. The axial flow fan blade as described in claim 5, characterized in that, The height of the contour section is H, where 4mm ≤ H ≤ 0.045R, and R is the outer diameter of the blade.

7. The axial flow fan blade as described in claim 1, characterized in that, The outward inclination angle α of the blade winglet is 6°-18°.

8. The axial flow fan blade as described in claim 1, characterized in that, The radius of the transition fillet between the blade winglet and the suction surface is R1, and the radius of the transition fillet between the blade winglet and the pressure surface is R2, where R1 = (4~6.5)R2.

9. The axial flow fan blade as described in claim 1, characterized in that, The blade winglet has a first surface for connecting with the suction surface and a second surface for connecting with the pressure surface, and the first surface and the second surface intersect at the end of the blade winglet away from the blade.

10. An outdoor unit, characterized in that, include: The shell has a receiving cavity; and An axial flow fan is installed in the receiving cavity, the axial flow fan comprising the axial flow fan blades as described in any one of claims 1 to 9.

11. The outdoor unit as described in claim 10, characterized in that, The outdoor unit also includes an air guide ring installed in the receiving cavity. The air guide ring is coaxially arranged with the axial flow fan, and at least a portion of the blade fins overlap with the air guide ring along the axial direction of the air guide ring.

12. The outdoor unit as described in claim 11, characterized in that, Along the axial direction of the axial flow fan, the projected height of the blade winglet is H1, and the overlap height between the blade winglet and the air guide ring is H2, where H2 = (0.5~0.65)H1.

13. The outdoor unit as described in claim 11, characterized in that, The outdoor unit also includes a heat exchanger installed in the receiving cavity. The heat exchanger includes a straight section located on one side of the suction surface of the fan blade. The projection of the free end of the straight section along the axial direction of the air guide ring is located within the air guide ring.

14. The outdoor unit as described in claim 13, characterized in that, The free end distance of the straight segment of the heat exchanger, the distance at the intersection of the extension line of the axis of the axial fan and the heat exchanger is D1, and the inner radius of the guide ring is R1, wherein 0.7R1≤D1≤1.02R1.

15. An air conditioner, characterized in that, Including the outdoor unit and indoor unit as described in any one of claims 10 to 14, The indoor unit and the outdoor unit are connected by a flexible refrigerant pipe, and the flexible refrigerant pipe is pre-charged with refrigerant; and / or, the compressor of the air conditioner is located in the indoor unit.

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