EP2581607A1

EP2581607A1 - Axial flow fan and air conditioner

Info

Publication number: EP2581607A1
Application number: EP20120184410
Authority: EP
Inventors: Jeongtaek Park; Deok Huh; Jaehyuk Jung
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2011-10-12
Filing date: 2012-09-14
Publication date: 2013-04-17
Also published as: US20130091888A1; KR20130039481A; CN103047180A

Abstract

Provided are an axial flow fan and an air conditioner. The axial flow fan includes a plurality of blades (120). The blades (120) include corrugated parts (125) on ends thereof. The corrugated parts (125) include convex portions (125a) and concave portions (125b) that are alternately arranged.

Description

BACKGROUND

The present disclosure relates to an axial flow fan and an air conditioner.
Air conditioners are used to heat or cool indoor areas. Such an air conditioner includes: a compressor for compressing a refrigerant, a condenser for condensing the refrigerant discharged from the compressor, an expansion device for expanding the refrigerant discharged from the condenser, and an evaporator for evaporating the refrigerant expanded by the expansion device.
The condenser and the evaporator of the air conditioner are heat exchangers at which the refrigerant exchanges heat with surrounding air. The condenser and the evaporator may be provided in indoor and outdoor units. An axial flow fan may be provided at a side of a heat exchanger provided in an outdoor unit.
Such an axial fan includes a hub connected to a shaft of a motor and a plurality of blades provided on the outer surface of the hub. The hub and the blades may be provided as one part. If the axial flow fan is rotated by the motor, air is sucked owing to a pressure difference between the front and rear sides of the blades formed on the outer surface of the hub.
That is, outdoor air can be sucked into the outdoor unit by a suction force of the axial flow fan. At this time, the outdoor air passes through the heat exchanger disposed at an entrance side of the outdoor unit and exchanges heat with a refrigerant flowing in the heat exchanger to condense or evaporate the refrigerant. Then, the outdoor air is discharged from the outdoor unit by the blowing action of the axial flow fan.
However, in the case of axial flow fans of the related art, since surfaces defined from a hub to the tips of blades are curved, pneumatic resistance is concentrated at the tips of blades to cause wake currents. This reduces fan efficiency and causes noises.

SUMMARY

The present invention is defined by the claims.
Accordingly the invention provides an axial flow fan comprising a hub, and a plurality of blades extending radially from an outer surface of the hub, wherein corrugated parts are disposed on at least portions of edges of the blades, respectively, and the corrugated parts comprise convex portions and concave portions that are alternately arranged.
Preferably, the convex portions protrude upward from a surfaces of the blades.
The concave portions may also be recessed downward from the surfaces of the blades.
The corrugated parts may be disposed on trailing edges of the blades.
The convex portions and the concave portions may be alternately arranged along the trailing edges.
The convex portions and the concave portions are preferably reduced in size in a direction toward a center of the axial flow fan.
The corrugated parts may have S-shaped cross sections.
The convex portions and the concave portions may extend on surfaces of the blades toward leading edges of the blades by predetermined lengths.
The convex portions and the concave portions may extend concentrically to a center of the axial flow fan by predetermined lengths.
The convex portions may become lower and the concave portions may become shallower in directions toward the leading edges of the blades.
The invention also provides an air conditioner comprising a heat exchanger disposed in a case; an axial flow fan disposed at a side of the heat exchanger and comprising a plurality of blades; a compressor disposed at a side of the axial flow fan; and a barrier plate configured to separate a region in which the compressor is disposed from a region in which the axial flow fan and the heat exchanger are disposed, wherein corrugated parts are disposed on at least portions of trailing edges of the blades, respectively, and the corrugated parts comprise convex portions and concave portions that are alternately arranged.
The convex portions and the concave portions are preferably alternately arranged along the trailing edges.
The convex portions and the concave portions may be reduced in size in a direction toward a center of the axial flow fan.
The corrugated parts may have S-shaped cross sections.
The convex portions and the concave portions may extend on surfaces of the blades toward leading edges of the blades by predetermined lengths.
The convex portions may become lower and the concave portions may become shallower in directions toward the leading edges of the blades.
The invention further provides an air conditioner comprising a heat exchanger disposed in a case; an axial flow fan disposed at a side of the heat exchanger and comprises a plurality of blades; a compressor disposed at a side of the axial flow fan; a barrier plate configured to separate a region in which the compressor is disposed from a region in which the axial flow fan and the heat exchanger are disposed; and a shroud disposed at a front side of the axial flow fan to guide air discharged from the axial flow fan, wherein a shroud corrugated part is disposed on a discharge end of the shroud, and the shroud corrugated part comprises shroud convex portions and shroud concave portions that are alternately arranged.
Preferably, the shroud corrugate part is continuous in a circumferential direction of the discharge end of the shroud.
The shroud convex portions and the shroud concave portions may extend toward an entrance end of the shroud by a predetermined length.
The shroud convex portions may become lower and the shroud concave portions may become shallower in a direction toward the entrance end of the shroud.
Embodiments provide an axial flow fan and an air conditioner. Corrugated parts are provided on blades of the axial flow fan to reduce wake currents and thus to increase the efficient of the axial flow fan and reduce noises when air is sucked and discharged by the axial flow fan.
In one embodiment, an axial flow fan includes a plurality of blades. The blades include corrugated parts on ends thereof. The corrugated parts include convex portions and the concave portions that are alternately arranged.
In another embodiment, an air conditioner includes: a heat exchanger disposed in a case; an axial flow fan disposed at a side of the heat exchanger and comprising a plurality of blades; a compressor disposed at a side of the axial flow fan; and a barrier plate configured to separate a region in which the compressor is disposed from a region in which the axial flow fan and the heat exchanger are disposed, wherein each of the blades includes a corrugated part disposed on at least a portion of a trailing edge thereof , and the corrugated part includes convex portions and concave portions that are alternately arranged.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a front view illustrating an air conditioner according to a first embodiment.
Fig. 2 is a plan view illustrating the air conditioner according to the first embodiment.
Fig. 3 is a front view illustrating an axial flow fan according to the first embodiment.
Fig. 4 is a partial enlarged view illustrating the axial flow fan of Fig. 3.
Fig. 5 is a side view of the axial flow fan to the first embodiment.
Fig. 6 is a partial enlarged view illustrating the axial flow fan of Fig. 5.
Fig. 7 is a plan view illustrating an air conditioner according to a second embodiment.
Fig. 8 is a front view illustrating a shroud according to the second embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, an axial flow fan and an air conditioner will be described according to embodiments of the present disclosure with reference to the accompanying drawings.
Fig. 1 is a front view illustrating an air conditioner 1 according to a first embodiment, and Fig. 2 is a plan view illustrating the air conditioner 1 according to the first embodiment.
Referring to Figs. 1 and 2, the air conditioner 1 of the first embodiment includes a case 10, a heat exchanger 20, a fan 100, a motor 30, a filter (not shown), a compressor 40, and a barrier plate 50. The air conditioner 1 may mean an outdoor unit.
The case 10 includes: a rear panel 11 forming the rear side of the air conditioner 1; lateral panels 12 coupled to the rear panel 11 for forming the lateral sides of the air conditioner 1; a top panel 13 forming the topside of the air conditioner 1; a front panel 14 forming the front side of the air conditioner 1; and a base panel 15 coupled to the lateral panels 12, the rear panel 11, and the front panel 14 for forming the bottom side of the air conditioner 1. In this way, the case 10 forms a hexahedral outer shape of the air conditioner 1. At least one of the panels of the case 10 may be provided in one piece.
The rear panel 11 and the lateral panels 12 include a rear air entrance part (not shown) and a lateral air entrance part (not shown). Grill members (not shown) may be disposed on the air entrance parts to block foreign substances. In this case, outdoor air is introduced into the case 10 through the grill members disposed on the rear panel 11 and the lateral panel 12.
An air discharge part 16 may be formed in the front panel 14. Similarly, a grill member (not shown) may be disposed on the air discharge part 16.
The heat exchanger 20 is disposed in the case 10 for heat exchange between outdoor air and a refrigerant. The heat exchanger 20 may be a fin-tube heat exchanger constituted by a refrigerant tube and a plurality of heat-exchange fins through which the refrigerant tube is inserted.
The heat exchanger 20 is disposed around an entrance side of the fan 100. In the air conditioner 1, the heat exchanger 20 makes contact with the rear panel 11 and one of the lateral panels 12. The heat exchanger 20 may be mounted on the base panel 15.
Air is introduced into the air conditioner 1 through the lateral air entrance part of the lateral panel 12 and the rear air entrance part of the rear panel 11. Then, the air passes through the heat exchanger 20. In detail, the air introduced into the case 10 may be cooled or heated by a refrigerant flowing in the refrigerant tube while the air passes through the heat-exchange fins. Thereafter, the cooled or heated air is discharged through the air discharge part 16 of the front panel 14. Owing to this heat exchange, an indoor area can be kept in a comfortable environment.
The fan 100 is disposed at a side of the heat exchanger 20. The fan 100 may be an axial flow fan 100 that sucks outdoor air and discharge the outdoor air while being rotated.
The axial flow fan 100 includes: a hub 110 connected to a shaft of the motor 30; and a plurality of blades 120 extending radially from the outer surface of the hub 110. The hub 110 and the blades 120 may be formed in one piece. Corrugated parts 125 may be formed on at least portions of edges of the blades 120 to reduce wake currents. The blades 120 of the axial flow fan 100 will be described later in more detail.
The motor 30 is connected to the axial flow fan 100 to rotate the axial flow fan 100. The shaft of the motor 30 may be connected to the hub 110 of the axial flow fan 100, and the motor 30 may be disposed at the rear side of the axial flow fan 100. The motor 30 may be disposed between the axial flow fan 100 and the heat exchanger 20. A motor support (not shown) may be coupled to the heat exchanger 20 or the rear panel 11 for supporting and fixing the motor 30.
The filter (not shown) is disposed close to the heat exchanger 20 to remove contaminants from air when air is introduced through the air entrance parts. The filter may be disposed between the heat exchanger 20 and the rear panel 11 or between the heat exchanger 20 and the lateral panel 12.
The compressor 40 may be disposed at a side of the axial flow fan 100 to compress refrigerant to high temperature and high pressure. The compressor 40 may have a cylindrical shape and be fixed to the base panel 15. The compressor 40 is connected to the heat exchanger 20 so that refrigerant can flow from the compressor 40 to the heat exchanger 20 or from the heat exchanger 20 to the compressor 40. Specifically, in cooling mode, the heat exchanger 20 functions as a condenser, and refrigerant discharged from the compressor 40 is introduced into the heat exchanger 20. On the other hand, in heating mode, the heat exchanger 20 functions as an evaporator, and refrigerant discharged from the heat exchanger 20 is introduced into the compressor 40.
The barrier plate 50 divides the inside of the case 10 into a compartment in which the compressor 40 is disposed and a compartment in which the heat exchanger 20 and the axial flow fan 100 are disposed. Owing to the barrier plate 50, air does not flow unnecessarily to the compressor 40 after passing through the heat exchanger 20. That is, flows of air can be efficiently controlled, and heating/cooling performance can be kept high.
Fig. 3 is a front view illustrating the axial flow fan 100 according to the first embodiment, and Fig. 4 is a partial enlarged view illustrating the axial flow fan 100 illustrated in Fig. 3. Fig. 5 is a side view illustrating the axial flow fan 100 according to the first embodiment, and Fig. 6 is a partial enlarged view illustrating the axial flow fan 100 illustrated in Fig. 5.
Referring to Figs. 3 to 6, the axial flow fan 100 of the first embodiment includes the hub 110 and the blades 120. A shaft (not shown) is coupled to the hub 110 to rotate the axial flow fan 100. As the blades 120 are rotated, air is forced to flow. In more detail, the blades 120 include: leading edges 121 formed at the front sides in a rotation direction of the blades 120; trailing edges 122 formed at the rear edges in the rotation direction of the blades 120; roots 123 which are inner ends of the blades 120; and tips 124 which are outer ends of the blades 120.
The corrugated parts 125 are formed on at least portions of edges of the blades 120. The corrugated parts 125 include convex portions 125a and concave portions 125b that are alternately arranged.
Surfaces of the blades 120 facing the heat exchanger 20 are positive-pressure surfaces that receive a positive pressure by air passing through the heat exchanger 20, And surfaces of the blades 120 not facing the heat exchanger 20 are negative-pressure surfaces opposite to the positive-pressure surfaces.
The corrugated parts 125 may be formed on the trailing edges 122. When air introduced into the axial flow fan 100 along the leading edges 121 is discharged along the trailing edges 122, wake currents of the air can be removed by the corrugated parts 125.
The convex portions 125a and the concave portions 125b may be alternately arranged along the trailing edges 122 and may decrease in size as it goes to the center of the axial flow fan 100. The flow rate of air discharging from the axial flow fan 100 along the trailing edges 122 may increase in a direction away from the center of the axial flow fan 100. Therefore, in the current embodiment, the convex portions 125a and the concave portions 125b distant from the center of the axial flow fan 100 may be greater than the convex portions 125a and the concave portions 125b close to the center of the axial flow fan 100 so as to suppress wake currents. The term 'great(er)' means that the heights of convex portions or the depths of concave portions are great or the widths of convex and concave portions are great.
The corrugated parts 125 may have S-shaped cross sections. That is, the convex portions 125a and the concave portions 125b may be connected in a curved shape. This structure reduces wake currents while not disturbing a discharge flow of air, and thus a sufficient discharge flow rate can be assured.
The convex portions 125a may protrude upward from the surfaces of the blades 120, and the concave portions 125b may be recessed downward from the surfaces of the blades 120. Air introduced along the leading edges 121 flows along surfaces of the blades 120 and is discharged along the trailing edges 122. At the time when the air is discharged along the trailing edges 122, flows of the air are varied by the convex portions 125a and the concave portions 125b. In the current embodiment, since flows on the positive-pressure surfaces and negative-pressure surfaces of the blades 120 can be mixed at the corrugated parts 125, the intensity and region of wake currents can be reduced. Furthermore, according to the current embodiment, since wake currents can be suppressed, noise can also be reduced for user's satisfaction.
The convex portions 125a and the concave portions 125b may extend on the blades 120 toward the leading edges 121 by predetermined lengths. In detail, the convex portions 125a and the concave portions 125b may extend concentrically to the center of the axial flow fan 100 by predetermined lengths. In this case, as it goes toward the leading edges 121, the heights of the convex portions 125a and the depths of the concave portions 125b may be reduced.
Therefore, air flowing on the surfaces of the blades 120 may be less disturbed at the trailing edges 122 by the corrugated parts 125. In this state, air flowing on the positive-pressure surfaces of the blades 120 may be smoothly mixed with air flowing on the negative-pressure surfaces of the blades 120 at the corrugated parts 125, and thus wake currents may be suppressed.
Fig. 7 is a plan view illustrating an air conditioner 1 according to a second embodiment, and Fig. 8 is a front view illustrating a shroud 60 according to the second embodiment.
Referring to Figs. 7 and 8, the air conditioner 1 of the second embodiment includes a case 10, a heat exchanger 20, a fan 100, a motor 30, a filter (not shown), a compressor 40, and a shroud 60. The air conditioner 1 of the second embodiment has the same structure as that of the air conditioner 1 of the first embodiment except for the shroud 60. Thus, a detailed description of the same structure will not be repeated. However, the fan 100 of the second embodiment may be an axial flow fan that has the same structure as the axial flow fan 100 of the first embodiment or does not include corrugated parts.
The shroud 60 is disposed at the front side of the axial flow fan 100 to guide air discharged from the axial flow fan 100. The shroud 60 may have a hollow cylinder shape with a size corresponding to the size of the axial flow fan 100. Alternatively, the shroud 60 may have a hollow truncated cone shape the diameter of which reduces as it goes away from the axial flow fan 100.
A shroud corrugated part 61 may be formed on a discharge end of the shroud 60. The shroud corrugated part 61 may include shroud convex portions 61a and shroud concave portions 61b that are alternately arranged. The shroud convex portions 61a may protrude toward the inside of the shroud 60, and the shroud concave portions 61b may protrude outward from the shroud 60.
That is, in the second embodiment, the shroud 60 may be additionally used, and the shroud corrugated part 61 of the shroud 60 may have a shape similar to that of the corrugated parts 125 of the blades 120 of the first embodiment.
In the second embodiment, owing to the shroud 60 including the shroud corrugated part 61, flows of air may be concentrated to increase the flow rate of the air, and wake currents may be reduced after air passes through the axial flow fan 100.
The corrugated part 61 may have an S-shaped cross section. That is, the shroud convex portions 61a and the shroud concave portions 61b may be connected in a curved shape. Owing to this structure, flows of air may be less disturbed as described in the description of the corrugated parts 125 of the first embodiment.
The shroud convex portions 61a and the shroud concave portions 61b extend toward an entrance end of the shroud 60 by a predetermined length. At this time, the heights of the shroud convex portions 61a and the depths of the shroud concave portions 61b may be reduced as it goes toward the entrance end of the shroud 60.
The shroud corrugated part 61 may be continuous in the circumferential direction of the discharge end of the shroud 60. For example, if the shroud convex portions 61a and the shroud concave portions 61b are arranged around the center of the shroud 60 and each has an angular width of 5 degrees, the number of the shroud convex portions 61a formed on the discharge end of the shroud 60 may be thirty six, and the number of the shroud concave portions 61b formed on the discharge end of the shroud 60 may also be thirty six. The shroud convex portions 61a and the shroud concave portions 61b are alternately arranged on the discharge end of the shroud 60.
Therefore, according to the second embodiment, noise can be reduced by suppressing wake currents by using corrugated parts 125 of the axial flow fan 100. In addition, after air passes through the axial flow fan 100, wake currents can also be suppressed by using the shroud corrugated part 61 of the shroud 60 to increase the flow rate of air at the same or lower level of power consumption.
According to the embodiments, owing to the corrugated parts disposed on the blades of the axial flow fan, air flowing on positive-pressure surfaces of the blades can be effectively mixed with air flowing on negative-pressure surfaces of the blades, and thus the intensity and area of wake currents can be reduced after the blades.
In addition, according to the embodiments, since wake currents can be reduced owing to the corrugated parts, the axial flow fan may consume less power, and noise can be reduced while air is sucked and discharged by the axial flow fan. Therefore, users may use the axial flow fan with more satisfactory.
In addition, according to the embodiments, the shroud is provided on the front side of the axial flow fan to prevent wake currents more effectively when air is discharged from the axial flow fan by using the shroud corrugated part of the shroud.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

An axial flow fan comprising:
a plurality of blades (120),

wherein corrugated parts (125) are disposed on at least portions of edges of the blades (120), respectively, and

the corrugated parts (125) comprise convex portions (125a) and concave portions (125b) that are alternately arranged.
The axial flow fan according to claim 1 comprising a hub (110), wherein the blades extend radially from an outer surface of the hub.
The axial flow fan according to claim 1 or 2, wherein the convex portions (125a) protrude upward from a surfaces of the blades (120), and the concave portions (125b) are recessed downward from the surfaces of the blades (120).
The axial flow fan according to claim 1,2, or 3, wherein the corrugated parts (125) are disposed on trailing edges (122) of the blades.
The axial flow fan according to claim 4, wherein the convex portions (125a) and the concave portions (125b) are alternately arranged along the trailing edges (122).
The axial flow fan according to claim 1, 2, 3, or 4, wherein the convex portions (125a) and the concave portions (125b) are reduced in size in a direction toward a center of the axial flow fan.
The axial flow fan according to any one of the preceding claims, wherein the corrugated parts (125) have S-shaped cross sections.
The axial flow fan according to any one of the preceding claims, wherein the convex portions (125a) and the concave portions (125b) extend on surfaces of the blades toward leading edges (121) of the blades (120) by predetermined lengths.
The axial flow fan according to any one of the preceding claims, wherein the convex portions (125a) and the concave portions (125b) extend concentrically to a center of the axial flow fan (100) by predetermined lengths.
The axial flow fan according to claim 8 or to claim 9 dependent on claim 8, wherein the convex portions (125a) become lower and the concave portions (125b) become shallower in directions toward the leading edges (121) of the blades (120).
An air conditioner comprising:
a heat exchanger (20) disposed in a case;

an axial flow fan (100) according to any one of the preceding claims, wherein the axial flow fan is disposed at a side of the heat exchanger;

a compressor (40) disposed at a side of the axial flow fan (100); and

a barrier plate (50) configured to separate a region in which the compressor (40) is disposed from a region in which the axial flow fan (100) and the heat exchanger (20) are disposed.
An air conditioner comprising:
a heat exchanger (20) disposed in a case;

an axial flow fan (100) disposed at a side of the heat exchanger (20) and comprising a plurality of blades (120);

a compressor (40) disposed at a side of the axial flow fan (100);

a barrier plate (50) configured to separate a region in which the compressor (40) is disposed from a region in which the axial flow fan (100) and the heat exchanger (20) are disposed; and

a shroud (60) disposed at a front side of the axial flow fan (100) to guide air discharged from the axial flow fan,

wherein a shroud corrugated part (61) is disposed on a discharge end of the shroud (60), and

the shroud corrugated part (61) comprises shroud convex portions (61a) and shroud concave portions (61b) that are alternately arranged.
The air conditioner according to claim 12, wherein the shroud corrugate part (61) is continuous in a circumferential direction of the discharge end of the shroud (60).
The air conditioner according to claim 12 or 13, wherein the shroud convex portions (61a) and the shroud concave portions (61b) extend toward an entrance end of the shroud (60) by a predetermined length.
The air conditioner according to claim 12, 13, or 14, wherein the shroud convex portions (61a) become lower and the shroud concave portions (61b) become shallower in a direction toward the entrance end of the shroud (60).