Centrifugal fan for devices including refrigerators

Abstract

A centrifugal fan for a refrigerator can include a plurality of vanes arranged radially about a central a shaft; a ring-shaped shroud coupled to the vanes and having a curved portion with a predetermined radius or curvature and also having an angled portion with a predetermined gradient or angle relative to the curved portion; and a bottom surface coupled to the vanes on the side opposite the shroud; where a ratio (r/R) of an inner diameter r, which is the shortest distance between the vane and the shaft, and an outer diameter R, which is the longest distance between the vane and the shaft, is approximately 0.690.01.

Claims

1. A centrifugal fan operable for use in a refrigerator, the centrifugal fan comprising: a plurality of vanes arranged radially about a central shaft; a ring-shaped shroud coupled to the vanes and comprising (i) a curved portion having a radius or curvature and (ii) an angled portion at an angle relative to the curved portion; and a bottom surface coupled to the vanes opposite the shroud, wherein the curved portion of shroud is formed closer to the inlet direction than the angled portion of shroud, wherein the shroud guides air from the curved portion to the angled portion, and wherein a ratio (r/R) of an inner radius r, which is the shortest distance between an inner edge of a vane of the plurality of vanes and the shaft, and an outer radius R, which is the longest distance between an outer edge of the vane and the shaft, is in a range of 0.690.01.

2. The centrifugal fan of claim 1, wherein the radius or the curvature of the curved portion corresponds to a shape of an inlet of the shroud and an element extending from the shroud.

3. The centrifugal fan of claim 1, wherein the radius or the curvature of the curved portion corresponds to an inlet width of the vane and an outlet width of the shroud, and the angle of the angled portion relative to the curved portion corresponds to the inlet width and the outlet width.

4. The centrifugal fan of claim 1, wherein a ratio of an outlet width of the shroud to a diameter of the centrifugal fan is in a range of 0.160.01.

5. The centrifugal fan of claim 1, wherein a ratio of an inlet width of the vane to a diameter of the centrifugal fan is in a range of 0.240.01.

6. The centrifugal fan of claim 1, wherein the vane has an inlet angle in a range of 251.

7. The centrifugal fan of claim 1, wherein the vane has an outlet angle in a range of 371.

8. The centrifugal fan of claim 1, wherein is the vane has a solidity ratio in a range of 1.00.1.

9. A refrigerator, comprising: an evaporator; a compartment; and a centrifugal fan configured to circulate air from the evaporator to the compartment, the centrifugal fan comprising a fan wheel comprising: a plurality of vanes; a ring-shaped shroud coupled to the vanes and comprising (i) a curved portion having a radius or curvature and (ii) an angled portion that is at an angle relative to the curved portion; and a surface coupled to the vanes opposite the shroud, wherein the curved portion of shroud is formed closer to the inlet direction than the angled portion of shroud, wherein the shroud guides air from the curved portion to the angled portion, and wherein a ratio (r/R) of a minimum radius of the fan wheel and a maximum radius of the fan wheel is in a range of 0.690.01.

10. The refrigerator of claim 9, wherein the radius or the curvature of the curved portion corresponds to a shape of an inlet of the shroud and an element extending from the shroud.

11. The refrigerator of claim 9, wherein the radius or the curvature of the curved portion corresponds to an inlet width of the vane and an outlet width of the shroud, and the angle of the angled portion relative to the curved portion corresponds to the inlet width and the outlet width.

12. The refrigerator of claim 9, wherein a ratio of an outlet width of the shroud to a maximum diameter of the fan wheel is in a range of 0.160.01.

13. The refrigerator of claim 9, wherein a ratio of an inlet width of the vane to a maximum diameter of the fan wheel is in a range of 0.240.01.

14. The refrigerator of claim 9, wherein the vane has an angle of attack in a range of 251.

15. The refrigerator of claim 9, wherein the vane has a blade angle in a range of 371.

16. The refrigerator of claim 9, wherein the vane has a solidity ratio in a range of 1.00.1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cross-sectional view of an example of a refrigerator.

(2) FIG. 2 is a cross-sectional view of the blower device installed in the refrigerator of FIG. 1.

(3) FIG. 3 is a diagram of a blower device in one or more exemplary embodiments according to the present disclosure.

(4) FIG. 4 is a cross-sectional view of the vanes of the exemplary centrifugal fan in one or more embodiments according to the present disclosure, along line A-A of FIG. 3.

(5) FIGS. 5(a), 5(b), and 5(c) illustrate vortex characteristics for various shroud shapes.

(6) FIG. 5(d) illustrates air flow for a shroud in one or more exemplary embodiments according to the present disclosure.

(7) FIG. 6 is a diagram illustrating comparative experimental results for noise level versus air volume flow rate.

(8) FIG. 7 is a diagram illustrating comparative experimental results for power consumption versus air volume flow rate.

DETAILED DESCRIPTION

(9) Hereinafter, exemplary embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings.

(10) In describing the exemplary embodiments, technical content that is well known in the technical field to which the present disclosure belongs and is not directly associated with the present disclosure may not be described. This is to more clearly describe and/or transfer the technical content by omitting unnecessary description(s).

(11) Some components may be exaggerated in size or omitted or schematically illustrated in the accompanying drawings. The drawings are not necessarily drawn to scale. The same reference numerals refer to the same or corresponding components in each drawing.

(12) FIG. 3 is a diagram of a blower device 50 that includes a centrifugal fan 60 that can be used in, for example, a refrigerator or air conditioner in one or more exemplary embodiments according to the present disclosure. FIG. 4 is a cross-sectional view of the fan wheel and/or vanes of the centrifugal fan along line A-A of FIG. 3.

(13) Referring to FIG. 3, the blower device 50 includes a housing 52 that has an inlet 52a and an outlet 52b, a centrifugal fan 60 in the housing 52, and a motor 70 that drives (e.g., rotates) the centrifugal fan 60 via a shaft 72.

(14) The housing 52 forms part of a flow path that circulates air into and through, for example, a refrigerator.

(15) Cool air enters the centrifugal fan 60 through the inlet 52a of the housing 52. The inlet 52 forms a bell mouth 51. The bell mouth 51 is used to more efficiently introduce air into and through the housing 52. The bell mouth 51 is convex (the bell mouth widens from the surface facing the motor 70 towards the inlet 52a of the housing 52).

(16) As illustrated in FIG. 3, the centrifugal fan 60 includes a plurality of vanes 62. Air is introduced through the inlet 52a of the housing 52 and flows to the outlet 52b of the housing 52. A ring-shaped shroud 64 connects the edges (e.g., upper exterior edges) of the plurality of vanes 62, and guides air from the inlet 52a to the inside of the centrifugal fan 60. A bottom surface 66 connects edges of the plurality of vanes 62 at the side opposite the shroud 64.

(17) In other words, with reference to FIG. 4, the circle C1 corresponds to the inner edges of the vanes 62, which are on the bottom surface 66 and inside the shroud 64, and the circle C2 corresponds to the outer diameter of the ring-shaped shroud 64. Part of the bottom edge of each of the vanes 62 is connected to the bottom portion 66, and part of the top edge of each of the vanes is connected to the shroud 64. The vanes 62 may curve. In one embodiment, they may have a convex outer surface (e.g., facing away from the shaft 72 and/or towards the outlet 52b) and a substantially convex inner surface (e.g., facing towards the shaft 72); otherwise, the vanes 62 may be planar or substantially planar, and have a rectangular or substantially rectangular cross-section.

(18) With reference to FIG. 3, the shroud 64 is separated from a neighboring element 51a that is connected to (extends from) the bell mouth 51 by a predetermined interval or distance.

(19) The shroud 64 includes a curved portion 64a that has a predetermined radius or curvature, and an angled portion 64b that is angled by a predetermined amount (e.g., in degrees) relative to the curved portion 64a. Alternatively, the angled portion 64b may be angled by a predetermined amount (e.g., in degrees) relative to the planar portion of the bottom portion 66.

(20) More specifically, the radius or curvature of the curved portion 64a is set according to the shapes of the inlet 52a and the element 51a. The radius or curvature of the curved portion 64a is set according to an inlet width or depth 621 and an outlet width or depth 622 of the shroud 64. The angle or gradient of the angled portion 64b may also be set according to the inlet width or depth 621 and the outlet width or depth 622 of the shroud 64.

(21) In one or more embodiments, the inlet width or depth 621 is the actual width of the vanes 62 at the edge closest to the center of the centrifugal fan, without considering the thickness of the bottom surface 66 of the centrifugal fan 60 (e.g., the inlet width 621 is the distance between the top/outer edge of the shroud 64 and the top/inner side of the bottom portion 66). The ratio of the inlet width 621 to the diameter of the centrifugal fan 60 (e.g., the diameter of the fan wheel) is 0.240.01, or in the range of approximately 0.240.01. The outlet width 622 is the actual width of the vanes 62 at the edges farthest from the center of the centrifugal fan, without considering the thickness of the shroud 64 (e.g., the outlet width 622 is the distance from the bottom/inner edge of the shroud 64 and the bottom/outer side of the bottom portion 66). The ratio of the outlet width 622 to the diameter of the centrifugal fan 60 may be 0.160.01, or in the range of approximately 0.160.01.

(22) As illustrated in FIG. 4, the vanes 62 have cross-sections that are shaped like an airplane wing or airfoil; in embodiments according to the present disclosure, the thickest cross-sectional portion of each vane is at or near the middle of the vane. Each of the vanes 62 includes a positive pressure surface 62a and a negative pressure surface 62b. The positive pressure surface may also be known as the pressure surface, and the negative pressure surface may be known as the suction surface. When the centrifugal fan 60 is turning, the vane 62 pushes air; thus, the pressure on the positive pressure surface 62a is higher than atmospheric pressure, and pressure is lower than atmospheric pressure on the negative pressure surface 62b. Each vane 62 includes: a front peripheral portion 62c on the pressure surface 62a and the negative pressure surface 62b that contacts cool air introduced through the inlet 52a; and a rear peripheral portion 62d on an outer circumference of the centrifugal fan 60 on the pressure surface 62a and the negative pressure surface 62b, and which discharges cool air to the outlet 52b.

(23) The vanes 62 form a virtual inner circle C1 with a radius r from the motor shaft 72 to the front peripheral portion 62c, and also form a virtual outer circle C2 with a radius R from the motor shaft 72 to the rear peripheral portion 62d. The inner radius r is the shortest distance between an inner edge of a vane of the plurality of vanes and the shaft, and an outer radius R is the longest distance between an outer edge of the vane and the shaft. The diameter of the circle C1 may be referred to herein as the minimum fan wheel diameter and thus the radius r may be referred to as the minimum fan wheel radius. The diameter of the circle C2 may be referred to herein as the maximum fan wheel diameter and thus the radius R may be referred to as the maximum fan wheel radius.

(24) In one or more embodiments according to the present disclosure, the ratio r/R (the radius r of the inner circle C1 to the radius R of the outer circle C2) is 0.690.01, or in a range of approximately 0.690.01.

(25) An inlet angle is defined herein as the angle between a tangent of the inner circle C1 and the front peripheral portion 62c of a vane 62. The angle may also be known as the angle of attack. In one or more embodiments according to the present disclosure, the inlet angle may be 251, or in a range of approximately 251. An outlet angle is defined herein as the angle between a tangent of the outer circle C2 and the rear peripheral portion 62d of a vane 62. The angle may also be known as the blade angle. In one or more embodiments according to the present disclosure, the outlet angle may be 371, or in a range of approximately 371.

(26) The outer tips and/or edges of the vanes 62 are separated from each other by a pitch P, which may be the length of an arc that connects the outer tips/edges of adjacent vanes (e.g., the length of an arc that connects an outlet angle in the outer circle C2 between the rear periphery portions 62d of any one vane and the nearest vane adjacent thereto and an outlet angle of the nearest/adjacent vane 62). If the vanes 62 are uniformly spaced, then the pitch is the circumference of the outer circle C2 divided by the number of vanes 62. At least one of the vanes 62 has a chord (e.g., a one-dimensional line from the innermost edge to the outermost edge, or between the vertices of the inner and outer angles) having a length L. A chord may also be a straight line that connects the front peripheral portion 62c and the rear peripheral portion 62d. In other words, a chord is generally a straight line connecting the leading and trailing edges of a vane 62. Typically, all of the vanes 62 have the same chord. In one or more embodiments according to the present disclosure, the ratio L/P, or blade solidity ratio, of the chord L and the pitch P is in the range of 1.00.1.

(27) FIGS. 5(a), 5(b), and 5(c) illustrate a vortex caused by different shroud shapes that may be used in conventional centrifugal fans.

(28) As illustrated in FIG. 5(a), when a shape 81 of the shroud has a round or curved portion 81a and a horizontal portion 81b, a vortex occurs at an interface between the round portion 81a and the horizontal portion 81b, generally toward the outlet.

(29) As illustrated in FIG. 5(b), when a shape 82 of the shroud has a tapered portion 82a and a horizontal portion 82b, a vortex larger than that of FIG. 5A occurs in the horizontal portion 81b, past the interface between the round portion 81a and the horizontal portion 81b, toward the outlet.

(30) As illustrated in FIG. 5(c), when a shape 83 of the shroud from a horizontal inlet 83a is only tilted (e.g., tapered surface 83b), collision loss resistance with a duct at or near the outlet is generated by a shaft-direction velocity component (e.g., of the air flow from the fan).

(31) FIG. 5(d) illustrates an exemplary air flow using embodiments of a shroud according to the present disclosure (e.g., the shroud 64 of FIG. 3). As illustrated in FIG. 5(d), in one or more embodiments according to the present disclosure, the shape 84 of the shroud 64 includes a curved portion 84a (64a) and an angled portion 84b (64b). Consequently, a vortex does not occur within or below the shroud or at the outlet, and collision losses are reduced.

(32) FIG. 6 is a diagram illustrating comparative results of experiments measuring noise level versus air volume flow rate in a centrifugal fan according to exemplary embodiment(s) of the present disclosure (e.g., having a shroud with a shape similar to or the same as FIG. 5(d)) and in a conventional centrifugal fan (e.g., having a shroud with a shape similar to or the same as FIG. 5(a)). FIG. 7 is a diagram illustrating results of experiments measuring power consumption versus air volume/flow rate in a centrifugal fan according to exemplary embodiment(s) of the present disclosure and in a conventional centrifugal fan.

(33) A noise level result 91b for the centrifugal fan 60 according to exemplary embodiment(s) of the present disclosure and a noise level result 91a for the conventional centrifugal fan are illustrated in FIG. 6. The centrifugal fan 60 generates less noise than the conventional centrifugal fan. For example, at an air volume flow rate of 35 CMH, the noise level of the centrifugal fan 60 is in the range of 21 to 22 dB (A), and the noise level of the conventional centrifugal fan is in the range of 24 to 25 dB (A). Thus, the noise level of the centrifugal fan 60 is 3 to 4 dB (A) lower than that of the conventional centrifugal fan. Alternatively, at the same noise level, the fan according to embodiment(s) of the present disclosure can move or circulate a volume of air over time that is about 15-20% or greater than the conventional centrifugal fan.

(34) Meanwhile, a power consumption result 92b for the centrifugal fan 60 according to exemplary embodiment(s) of the present disclosure and a power consumption result 92a for the conventional centrifugal fan are illustrated in FIG. 7. The power consumption of the present exemplary centrifugal fan 60 is lower than that of the conventional centrifugal fan. For example, the power consumption of the present exemplary centrifugal fan 60 is approximately 1.75 W for an air volume/flow rate of 35 CMH, and the power consumption of the conventional centrifugal fan is approximately 2.5 W at that air volume/flow rate. Thus, the power consumption of the centrifugal fan 60 is approximately 22 to 30% lower than that of the conventional centrifugal fan, and the improvement may increase at higher air flow rates.

(35) From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. The exemplary embodiments disclosed in the specification of the present disclosure will not limit the present disclosure. The scope of the present disclosure will be interpreted by the claims below, and it will be construed that all techniques within the scope equivalent thereto belong to the scope of the present disclosure.