KR101320805B1 - Fan blades and modifications - Google Patents

Abstract

The winglet of the present application is composed of a vertical member and a mounting member. The mounting member is configured to easily mount the winglet on the tip of the fan blade. The vertical member is formed to extend at right angles to the tip of the fan blade. By adding winglets to the fan blades, the aerodynamics of the fan blades are improved and the efficiency of the fans is increased.

Description

Fan blades and their variants {FAN BLADES AND MODIFICATIONS}

FIELD OF THE INVENTION The present invention relates to fan blades and fan blades, and more particularly to airfoils suitable for using fan blades and winglets suitable for using fan blades.

People working on large structures such as warehouses and factories may be exposed to uncomfortable or dangerous working conditions. Such a situation may also apply equally to farms, such as in structures filled with livestock. In hot weather, the air temperature inside can reach a temperature at which a person or animal cannot maintain a healthy or otherwise desirable body temperature. In areas where the temperature is unpleasant or unstable, it would be desirable to install a device that can operate to generate or improve airflow within that area. Such airflows are responsible for lowering the temperature of the area to some extent.

In addition, various activities performed in such an environment, such as welding or the operation of an internal combustion engine, can generate airborne pollutants that can be harmful to those exposed to the environment. The effects of airborne contaminants can be magnified if airflow in the area is not ideal. In such a situation, it is desirable to have a device in the area capable of generating or improving airflow. Such airflow reduces to some extent the adverse effects of the contaminants, for example to promote dilution and / or removal of the contaminants.

In certain structures and environments, it is a problem that heat collects near the ceiling of the structure. This is related to the fact that the area near the bottom of the structure is at a relatively low temperature. Those skilled in the art will readily recognize the disadvantages that may be caused by these or other unbalanced air / temperature distributions. In such or similar situations, it is desirable to install a device within the area that can operate to generate or improve airflow. Such airflow helps to some extent lead to de-stratification and an ideal air / temperature distribution.

Various embodiments of the present invention will be described below with reference to the accompanying drawings for the purpose of illustrating the basic principles and the present invention. Accordingly, the described embodiments are described for purposes of illustration and not of limitation. In addition, in the drawings, like reference numerals are assigned to understand the same elements.

It may be desirable to have a fan that can reduce energy consumption. Reduction of energy consumption consists of fans that operate efficiently (eg, consume less power to drive the fans compared to other fans). In addition, the reduction of energy consumption may be more effective by the fans with improved air distribution, which may reduce heating or cooling costs in conjunction with other devices.

1 is a plan view of a hub on which a fan blade is mounted.
2 is a cross-sectional view of an example fan blade airfoil.
3 is a cross-sectional view of another example fan blade airfoil.
4 is a graph showing two ellipses.
FIG. 5 illustrates a portion of the graph of FIG. 4. FIG.
6 is a side view of an example winglet fan blade modified.
Figure 7 is a cross sectional view of the winglet of Figure 6;
8 is a top view of the winglet of FIG.
Figure 9 is an end view of the fan blade of Figure 2 with the winglet of Figure 6 adapted.
10 is an exploded perspective view of the winglet-blade assembly of FIG.

Various embodiments of the present invention will be described below with reference to the accompanying drawings for the purpose of illustrating the basic principles and the present invention. Accordingly, the described embodiments are described for purposes of illustration and not of limitation. In addition, in the drawings, like reference numerals are assigned to understand the same elements.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described with reference to the accompanying drawings, in which like parts indicate like parts throughout. 1 shows an exemplary fan hub 10 used to provide a fan with fan blades 30 or 50. In an embodiment, the fan hub 10 includes a plurality of hub mounting members 12 on which fan blades 30 or 50 can be installed. In one embodiment, fan hub 10 is coupled to a drive mechanism that rotates fan hub 10 at an optional or predetermined speed. Thus, a suitable hub assembly includes the hub 10 and a drive mechanism coupled to the hub 10. Of course, the hub assembly can include a variety of other components with other hubs, and the fan hub 10 can be driven by any suitable means. In addition, the fan hub 10 may have any suitable number of hub mounting members 12.

As shown in Figs. 1 to 3, each hub mounting member 12 has an upper surface 14 and a lower surface 16 which terminate at the leading edge 18 and trailing edge 20 side. Has In addition, each hub mounting member 12 has an open hole 22 formed through the upper surface 14 and through the lower surface 16. In an embodiment, the aperture 22 is sized to accommodate the fastener 26. Each hub mounting member 12 is configured to receive a fan blade 30 or 50. Those skilled in the art will appreciate that the hub mounting member 12 can be provided in a variety of modified structures.

In one embodiment, fan blades 30 or 50 are mounted to the hub assembly disclosed in US Pat. No. 6,244,821. Of course, fan blades 30 or 50 may be mounted to any other hub and / or hub assembly. A suitable hub assembly allows the hub 10 to operate to rotate at any suitable angular speed. For example, the angular velocity is in the range of about 7 to 108 rpm in some region.

2 is a cross-sectional view of an exemplary fan blade 30 with a curled trailing edge 38 mounted to the hub 10. The cross section is cut along the cross section located in the center of the fan blade 30 as viewed toward the hub 10. The fan blade 30 has an upper face 32 and a lower face 34, each face ending at an anterior edge 36 and an anterior edge 38. As shown, the trailing edge 38 has an inclination of approximately 45 ° with respect to the upper surface 32 portion near the trailing edge 38 and the lower surface 34 portion near the trailing edge 38. Of course, the trailing edge 38 may have any other suitable slope, such as, for example, 0 °, in the range including the single flat surface. Other suitable back-end 38 structures will be readily appreciated by those skilled in the art.

In this embodiment, the fan blades 30 are almost hollow. A plurality of ribs or bosses 40 are disposed inside the fan blades 30. As shown, when the hub mounting member 12 is inserted into the fan blades 30, the ribs or bosses 40 are formed on the top surface 14, bottom surface 16, front edge of the hub mounting member 12. 18), and to engage with the anterior chamber 20. Thus, the boss 40 allows the fan blade 30 and the hub mounting member 12 to be snug fit to each other. Those skilled in the art will readily recognize other structures of the fan blades 30 that have a structure that affects the interrelationship between the fan blades 30 and the hub mounting member 12 with non-limiting substrates.

As used herein, the terms "chord", "cord length", "maximum thickness", "maximum camber", "angle of attack" and the like refer to airplane wings or other airfoil design technologies. It is used the same as the meaning of the term used in. In one embodiment, the cord length of fan blades 30 is approximately 6.44 inches (16.35 cm). The maximum thickness of the fan blades 30 is approximately 16.2% of the cord and the maximum camber is approximately 12.7% of the cord. The radius of lead 36 is approximately 3.9% of the cord. The radius of the trailing edge 38 of the quadrant of the lower face 34 is approximately 6.8% of the cord. In another embodiment, the cord of fan blade 30 is approximately 7 inches (17.78 cm). In another embodiment, the cord of fan blades 30 is approximately 6.6875 inches (16.9862 cm). Of course, any other suitable size and / or ratio may be used.

For example, fan blades 30 exhibit lift to drag ratios ranging from approximately 39.8 with a Reynolds number of approximately 120,000 to approximately 93.3 with a Reynolds number of approximately 250,000. Of course, the fan blades 30 can obtain different yield ratios.

In one embodiment, fan blade 30 exhibits drag coefficients ranging from approximately 0.027 with a Reynolds number of approximately 75,000 to approximately 0.127 with a Reynolds number of approximately 112,500. Of course, the fan blades 30 can obtain different drag coefficients.

In one example, with the Reynolds number approximately 200,000, the fan blades 30 move air such that the speed ratio is approximately 1.6 at the lower surface 34 of the trailing edge 38 of the fan blades 30. The fan blades 30 can obtain different speed ratios.

In one embodiment, fan blades 30 have an angle of attack of approximately -1 ° to 7 ° with a Reynolds number of approximately 112,000 and an angle of attack of approximately -2 ° to 10 ° with a Reynolds number of approximately 250,000. Provides non- stalled aerodynamics. Of course, these values are shown by way of example only.

FIG. 3 is a cross-sectional view of another example of a fan blade 50 having approximately elliptical upper and lower surfaces 52 and lower surfaces 54 extending from the front to the back 56 and the back to the front 58 mounted on the hub 10, respectively. to be. The cross-sectional view is cut along the transverse plane located at the center of the fan blade 50 as viewed toward the hub 10. In this example, the fan blade 50 is hollow. A plurality of bosses 60 are installed inside the fan blade 50. As shown, when the hub mounting member 12 is inserted into the fan blade 50, the boss 60 is the upper surface 14, the lower surface 16, the leading edge 18 of the hub mounting member 12 , And is located in contact with the trailing edge (20). Thus, the boss 60 allows the fan blade 50 and the hub mounting member 12 to be installed in a stable fit with each other. As a non-limiting substrate, a person skilled in the art can easily foresee another structure of the fan blade 50, which is made of a structure that affects the relationship between the fan blade 50 and the hub mounting member 12. will be.

As shown, the fan blade 50 has a radius of curvature that is smaller towards the leading edge 56, as compared to having a larger radius of curvature towards the trailing edge 58. As shown in FIG. The curvature of the fan blade 50 can be obtained at least in part through the generation of two ellipses using the following equation. One skilled in the art will appreciate that a first ellipse whose origin is the intersection of the x and y axes of the Cartesian coordinates can be made by the following equation.

[1] x = a (COS (t))

[2] y = b (SIN (t))

Where a = first radius length, b = second radius length, and t = radial rotation angle (eg, radians) relative to the origin.

Thus, the first ellipse can be generated using the above equation. Similarly, a pair of left � of the first ellipse can be obtained using the formulas [1] and [2]. For example, the first ellipse 200 is illustrated in the graph of FIG. 4, where a = 3 and b = 2.

The coordinates of the second ellipse are obtained using the following equation.

[3] x ₂ = x (COS (θ))-y (SIN (θ)),

[4] y ₂ = y (COS (θ))-x (SIN (θ))

Here, x ₂ is the second "x" coordinate after the first ellipse rotates in the system direction by θ radian with respect to the origin, and y ₂ is after the first ellipse rotates in the system direction by θ radians with respect to the origin. The second "y" coordinate.

Thus, the dimensions of the second ellipse are determined by the dimensions of the first ellipse. An example second ellipse 300 is illustrated in the graph shown in Figure 4, where θ = 0.525 radians. Here, it can be seen that the first and second ellipses are represented by coordinates according to equations [1] to [4], and the two ellipses cross each other (ellipse intersection) at four points. 4 is a diagram illustrating four ellipse intersections 400 between the first ellipse 200 and the second ellipse 300.

The curvature of the upper surface 52 and the lower surface 54 is based at least in part on the curvatures of the first and second ellipses between two consecutive elliptic intersections. FIG. 5 showing ellipses 200 and 300 between intersections 400 of consecutive ellipses shows an example of a section of the first ellipse 200 and the second ellipse 300. Therefore, the surface coordinates of at least the lower surface 54 and the upper surface 52 of the fan blade 50 can be generated using the formulas [1] to [4].

It will be appreciated that the cord length to thickness ratio of the fan blade 50 will vary with the amount of rotation θ for the two ellipses.

Of course, portions of the fan blades 50 deviate from the curves of the first and second ellipses. For example, the leading edge 56 may be modified to have a nearly circular curve. Those skilled in the art will appreciate that other variations may be made.

In one embodiment, the fan blade 50 is obtained using equations [1] to [4], where a = 3 units, b = 2 units, and θ = 0.525 radians. In this embodiment, the fan blade 50 is installed with a circular front 56 with a diameter of 3.5% of the cord length. This bending of the leading edge 56 coincides tangentially with the curves of the upper surface 52 and the lower surface 54. The match can be seen in contrast to FIGS. 3 and 5. Of course, other dimensions may be used.

In one embodiment, fan blade 50 has a cord length of approximately 7.67 inches (19.48 cm). In another embodiment, the fan blades have a cord length of approximately 7.687 inches (19.524 cm). Of course, fan blades 50 may have other suitable cord lengths.

In this example, the radius of leading 56 is approximately 3.5% of the cord. The maximum thickness of the fan blade 50 is approximately 14.2% of the cord. The maximum camber of the fan blade 50 is approximately 15.6% of the cord. Of course, all other suitable dimensions and / or ratios may be used.

For example, a fan with a diameter of 24 feet (7.3m) and 10 fan blades 50 installed at an angle of attack of 10 °, when rotated at approximately 7 rpm, generates approximately 5.2 lb (2.359 kg) of thrust resulting in approximately 87,302 Perform cfm (cubic feet per minute) displacement. Spinning at approximately 14 rpm, the fan generates approximately 10.52 lb of thrust and approximately 124,174 cfm displacement. When rotating at approximately 42 rpm, the fan generates approximately 71.01 lb of thrust and approximately 322,613 cfm displacement. Other thrust and / or displacement volumes can be obtained with the fan of the fan blade 50.

As an example, a fan blade 50 having an angle of attack of approximately 10 ° exhibits a lift ratio ranging from approximately 39 with a Reynolds number of approximately 120,000 to approximately 60 with a Reynolds number of approximately 250,000. The fan blade 50 can obtain different yield ratios.

In one embodiment, the fan blade 50 has an angle of attack between approximately 0 ° and 13 ° with a Reynolds number of approximately 200,000, for an angle of attack between approximately 1 ° and 11 ° with a Reynolds number of approximately 112,000. In addition, it provides non-stall aerodynamics for angles of attack between approximately 1 ° and 13 ° with a Reynolds number of approximately 250,000. Of course, these values are shown by way of example only.

In one example, a fan with a diameter of 14 feet (4.2 m) and ten fan blades 50 is rotated at approximately 25 rpm. The fans operate at approximately 54 watts with a torque of approximately 78.80 inches-pounds (in. Lbs.) And a flow rate of approximately 34,169 cfm. Thus, the efficiency of the fan is approximately 632.76 cfm / watt.

In another example, a fan with a diameter of 14 feet (4.2 m) and ten fan blades 50 is rotated at approximately 37.5 rpm. The fan operates at approximately 82 watts with a torque of approximately 187.53 inches-pounds (in. Lbs.) And a flow rate of approximately 62,421 cfm. Thus, the efficiency of the fan is approximately 761.23cfm / watt.

In another example, a fan 14 feet (4.2 m) in diameter and having 10 fan blades 50 is rotated at approximately 50 rpm. The fan operates at approximately 263 watts with a torque of approximately 376.59 inches-pounds (in. Lbs.) And a flow rate of approximately 96,816 cfm. Thus, the efficiency of the fan is approximately 368.12 cfm / watt.

The following is merely described by way of example, but may be applied to all fan blades including fan blades 30 or fan blades 50.

In one embodiment, each fan blade 30 or 50 comprises a continuum of homogeneous material. In one simple example, fan blades 30 and 50 may be constructed of extruded aluminum. However, fan blades 30 and / or 50 may be composed of any other suitable material (s) including any metal and / or plastic as a non-limiting substrate. In addition, fan blades 30 and / or 50 are manufactured by any suitable manufacturing method including stamping, bending, welding, and / or molding with non-limiting substrates. Those skilled in the art will also be able to anticipate other suitable manufacturing methods and materials.

When fan blades 30 or 50 are mounted to hub 10, hub mounting member 12 extends into fan blades 30 or 50, for example approximately 6 inches (15.24 cm). Optionally, the hub mounting member 12 can extend into any suitable length into the fan blades 30 or 50. Also, as can be expected, the hub 10 may have a mounting member 12 installed externally, not into the fan blades 30 or 50. Alternatively, the mounting member 12 may be partially installed on both sides of the fan blade 30 or 50 and partially outside.

The fan blades 30 or 50 may also have one or more drilled holes configured to coincide with the drilled holes 22 of the hub mounting member 12. In this embodiment, if the opening in the fan blades 30 or 50 matches the opening 22 in the hub mounting member 12, the fastener 26 is inserted through the opening so that the fan blades 30 or 50 can be inserted. ) May be fixed to the hub mounting member 12. In one embodiment, fastener 26 is a bolt. Those skilled in the art will appreciate that the adhesive may be included as a non-limiting substrate as another suitable substitute for fastener (s) 26. Therefore, it can be understood that the opening 22 is selectively selected.

Fan blades 30 or 50 are approximately 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or 14 feet long (1.2, 1.5, 1.8, 2.1, 2.4, 2.7, 3.0, 3.3). , 3.6, 3.9, or 4.2 m). Optionally, fan blades 30 or 50 can be of any other suitable length. In one embodiment, fan blades 30 or 50 and hub 10 are sized such that the diameter of the fan comprising fan blades 30 or 50 and hub 10 is approximately 24 feet (7.3 m). In other embodiments, fan blades 30 or 50 and hub 10 are sized such that the diameter of the fan comprising fan blades 30 or 50 and hub 10 is approximately 14 feet (4.2 m) in diameter. Those skilled in the art will appreciate that other suitable dimensions can be achieved.

It will be appreciated that not all cross sections along the length of the fan blades 30 or 50 need to be identical. That is, the structure of the fan blades 30 or 50 need not be made constant along the entire length of the fan blades 30 or 50. As an example, a part of the "hub mounting end" of the fan blades 30 or 50 (ie, the other end of the fan blades 30 or 50 mounted to the hub 10) may be removed. In one example, the front edge 56 of the fan blade 50 may be obliquely cut to accommodate the other blade 50 in the hub 10.

Optionally, some or other portions of the hub mounting end may be omitted, removed, or otherwise "missed" to form or form fan blades 30 or 50. The absence of such a portion (whether removed or not present from the beginning) may foresee a problem with the fan blades 30 or 50 interfering with each other at the location of the hub 10. Such interference is caused by a variety of factors including, but not limited to, the cord length of the fan blades 30 or 50. Of course, factors other than interference may affect the removal of, or otherwise absent, portions of the fan blades 30 or 50. The missing portion may comprise a portion of the anterior segment 36 or 56, a portion of the trailing segment 38 or 58, or both portions.

Optionally, the diameter of the hub may be increased (eg, without increasing the number of hub mounting members 12) to resolve interference of the fan blades 30 or 50 at the hub 10. Alternatively, the cord of the fan blades 30 or 50 can be shortened. Those skilled in the art will appreciate other alternatives and modifications of the hub 10 and / or fan blades 30 or 50.

Those skilled in the art will appreciate that the angle of attack of the fan blades 30 or 50 may be zero or non-zero. In one example, when mounted to hub mounting member 12, fan blades 30 or 50 may, for example, comprise approximately −1 ° to 7 ° (including 7 °); -2 ° to 10 ° (including 10 °); Or an angle of attack in the range of approximately 7 °, 8 °, 10 °, or 13 °. Of course, fan blades 30 or 50 may have any other suitable angle of attack. The fan blades 30 or 50 may be made nearly straight along the length, or the angle of attack may be provided to have a hub mounting member 12 with a desired angle of attack.

Optionally, the angle of attack of the hub mounting member 12 may be zero, and the angle of attack may be provided to the fan blades 30 or 50 by twisting the fan blades 30 or 50. That is, the fan blades 30 or 50 are made generally straight along the length of the hub mounting member 12 extending into the fan blades 30 or 50, and the angle of attack relative to the rest of the fan blades 30 or 50 is established. Torsion may be given to give. Such torsion can be produced over all suitable lengths of the fan blades 30 or 50 (eg, the entirety of the remainder of the length of the fan blades 30 or 50 is torsional; or the torsion is short and hence the fan blades are Almost all of the remainder of (30 or 50) is generally linear; and so on). One of ordinary skill in the art would envision other suitable structures and methods for providing angle of attack to all or a portion of the fan blades 30. It may also be foreseen that all or part of the fan blades 30 or 50 may have one or more twists for any purpose.

Those skilled in the art will appreciate that the fan blades (eg, 30 or 50) may be modified in various ways. Such modifications will change the characteristics of the fan performance. As shown, for example, in FIGS. 6-10, the winglets 70 may be included in one such modification. Winglets 70 are described with respect to fan blades 30 or 50, although the winglets 70 may be used for any other suitable fan blade.

The winglet 70 in this example includes a vertical member 72. The vertical member 72 includes a flat inner surface 74 and a rounded outer surface 76. Those skilled in the art will appreciate other suitable structures of the inner surface 74 and the outer surface 76. In this example, the perimeter of the vertical member 72 is defined by the lower edge 78, the upper edge 80, and the rear edge 82. Each edge 78, 80, 82 is generally joined at each edge 84. Thus, in this example, the vertical member 72 has three edges 84. As shown, each edge 84 is rounded. Thus, the term "edge" as used herein should not be understood as reminiscent of a sharp angle. That is, the edges should not be limited to the points or areas where a set of straight lines meet or intersect. Although the vertical member 72 is described as having three corners in this example, the vertical member 72 may have an appropriate number of corners 84.

Other modifications of the vertical member 72 will be readily apparent to those skilled in the art.

In addition, the winglet 70 of this example further includes a winglet mounting member 90, which extends substantially at right angles from the inner surface 74 of the vertical member 72. As shown, the winglet mounting member 90 has a structure similar to the hub mounting member 12. The winglet mounting member 90 has an upper surface 92 and a lower surface 94, each extending to the front anterior 96 and the rear anterior 98. In addition, each winglet mounting member 90 includes an open hole 100 formed through an upper surface 92 and a lower surface 94. In this example, each open hole 100 is sized to receive the fastener 26. The winglet mounting member 90 is configured to be inserted into one end of the fan blade 30 or 50. Those skilled in the art will appreciate that the winglet mounting member 90 may be provided in a variety of alternative structures.

9 is a cross sectional view of the fan blade 30 with the winglets 70 mounted thereon. This cross sectional view is shown and shown toward the winglet 70 cut along the cross section located at the center of the fan blade 30 (ie, away from the hub 10). In this example, as shown in Figs. 9 and 10, the winglet mounting member 90 is configured to fit at one end of the fan blades 30 or 90. Similar to the hub mounting member 12, the winglet mounting member 90 is securely installed and engaged with respect to the boss 40 or 60 of the fan blades 30 or 50. In this example, the upper edge 80 of the winglet 70 extends above the top surface 32 or 52 of the fan blades 30 or 50 and also extends beyond the leading edge 36 or 56. Likewise, the lower edge 78 of the winglet 70 extends below the lower surface 34 or 54 of the fan blades 30 or 50. The rear edge 82 of the winglet 70 extends beyond the trailing edge 38 or 58 of the fan blades 30 or 50. Of course, the winglets 70 and fan blades 30 or 50 may both have different relative sizes and / or structures.

The fan blades 30 or 50 may have one or more openings formed through the upper surface 32 or 52 and / or the lower surface 34 or 54 near the tip of the fan blades 30 or 50, This hole is positioned coincident with the open-hole (s) 100 in the winglet mounting member 90 when the winglet mounting member 90 is inserted into the fan blades 30 or 50 and receives the fastener 26. Size. Thus, the winglets 70 are secured to the fan blades 30 or 50 by one or more fasteners 26. In one embodiment, fastener 26 is a bolt. In another embodiment, the fasteners 26 are complementary pairs of thin head interlocking screws, for example threaded posts (e.g. "male" screws with threaded outer surfaces) commonly used to wind many papers together. Pictured and configured to engage with a "female" screw with an inner surface). However, other suitable fastener (s) may be used including, but not limited to, adhesives. Thus, it will be appreciated that the open hole 100 is optional.

It will also be appreciated that the winglet mounting member 90 does not have to be inserted into the end of the fan blades 30 or 50. In other words, like the hub mounting member 12, the winglet mounting member 90 may be manufactured to be installed at the outer side of the fan blade 30 or 50 instead of the inner side thereof. Optionally, the winglet mounting member 90 may be installed on both sides, partly inside the fan blades 30 or 50 and partly outside the fan blades 30 or 50. Those skilled in the art will appreciate that other structures may exist.

In another embodiment, the winglet 70 removes the mounting member 90 and instead forms a recess in the inner surface 74 of the vertical member 72. In this embodiment, the tip of the fan blades 30 or 50 is inserted into the winglets 70 to attach the winglets 70 to the fan blades 30 or 50. In another embodiment, fan blades 30 or 50 are integrally formed with winglets 70. Thus, those skilled in the art will anticipate that there are various structures for installing the winglets 70 to the fan blades 30 or 50.

Although the vertical member 72 is shown to be nearly perpendicular to the mounting member 90, the two members are at any suitable angle with respect to each other. Thus, for example, when the winglets 70 are attached to the fan blades 30 or 50, the vertical member 72 may be inclined inward or outward. Optionally, the vertical member 72 may comprise several angles. That is, when the winglets are attached to the fan blades 30 or 50, the vertical member 72 may be configured such that the upper portion of the vertical member and the lower portion of the vertical member are inclined inward. One of ordinary skill in the art would appreciate that modifications of other winglets 70 include angle changes to non-limiting substrates.

Although the winglets 70 have been specifically described herein as modifications to the fan blades 30 or 50, the winglets 70 may be used to modify any other fan blade.

In one embodiment, the winglets 70 are formed of a homogeneous continuum of molded plastic. However, the winglets 70 may be made of a variety of materials, including any suitable metal and / or plastic, with no limitation, and may include a plurality of pieces. In addition, the winglets can be produced by any suitable manufacturing method.

Further, trailing vortices occurring at or near the tip of fan blades 30 or 50 will increase lift near the tip of fan blades 30 or 50. The winglets 70 suppress radial air flow across the top surface 32 or 52 and / or the bottom surface 34 or 54 near the tip of the fan blades 30 or 50. Such suppression allows air to flow more gracefully from the leading edge 36 or 56 to the trailing edge 38 or 58, thereby improving the efficiency of the fan with fan blades 30 or 50 with winglets 70 at least at any rotational speed. Can be improved.

In one example, winglets 70 were attached to the ends of fan blades 30 or 50 in a 6 foot (1.8 m) fan. By adding winglets 70, the air flow rate of the fan was increased by 4.8% to 171 rpm.

In another example, winglets 70 were attached to the ends of fan blades 30 or 50 in a 14 ft (4.2 m) fan. By adding winglets 70, the fan's air flow increased by 4.4% to 75 rpm.

The two tables below show the efficiency obtained by adding the winglets 70 to a 14 ft (4.2 m) fan.

Fan without winglets (70) Speed (rpm) Max Power (watt) Average Power (watt) Torque (in.lbs) Flow rate (cfm) Efficiency (cfm / watt) 12.5 54 50 17.86 0 0 25 66 54 78.80 34,169 632.76 37.5 125 82 187.53 62,421 761.23 50 339 263 376.59 96,816 368.12 62.5 700 660 564.01 110,784 167.85 75 1170 1140 839.75 129,983 114.02

Fan with winglet (70) Speed (rpm) Max Power (watt) Average Power (watt) Torque (in.lbs) Flow rate (cfm) Efficiency (cfm / watt) 12.5 50 42 18.56 26,815 638.45 25 58 43 18.39 46,547 1,082.49 37.5 68 49 186.00 61,661 1,258.39 50 241 198 354.61 87,552 442.18 62.5 591 528 582.78 120,859 228.90 75 980 950 847.41 136,560 143.75

Of course, the winglets 70 may be used to obtain other values. In addition, as will be appreciated by those skilled in the art, other winglet structures may be obtained by appropriately changing the winglets with non-limiting substrates.

In summary, the specification herein describes many of the advantages obtained using the concepts of the present invention. The above-described various embodiments of the invention have been described for purposes of illustration, and are not intended to limit the invention. The present invention is intended to embrace all such various changes and modifications as may be made without departing from the spirit of the appended claims based on the foregoing description.

10: Hub 18: Ahead
20: behind 30, 50: fan blade
70: winglet 72: vertical member

Claims (20)

A fan blade configured to be mounted to a rotating fan hub,
The fan blade is
An upper surface having an elliptical curvature;
A bottom surface having an elliptic curvature;
The front edge of which the upper and lower surfaces are terminated, respectively; And
Including the trailing edge where the upper and lower surfaces terminate respectively,
The curvature of the upper surface is formed of a first ellipse and the curvature of the lower surface is formed of a second ellipse. The method of claim 1,
Further comprising a first radius of curvature and a second radius of curvature,
The front blade is formed with a first radius of curvature, the rear blade is formed with a second radius of curvature, wherein the first radius of curvature is less than the second radius of curvature. The method of claim 1,
And the curvature of the second ellipse depends on the curvature of the first ellipse. The method of claim 1,
And the fan blade is hollow. The method of claim 1,
And the fan blade is configured to receive the mounting member of the fan hub. The method of claim 5,
And the fan blade is fixed to the fan hub by at least one fastener. The method of claim 1,
Said fan blade having a cord and a maximum thickness, said maximum thickness being approximately 14.2% of said cord. The method of claim 1,
Wherein said fan blade has a cord and a maximum camber, said maximum camber being approximately 15.6% of said cord. The method of claim 1,
And the fan blade is mounted to the hub at an angle of attack between and including -1 ° and 13 °. The method of claim 1,
And the fan blade is formed of extruded aluminum. The method of claim 1,
And the fan blades have a length between and including 4 feet and 14 feet. The method of claim 1,
And the fan blade has a constant cross section along the entire length of the fan blade. The method of claim 1,
The fan blade has a hub mounting end, characterized in that the oblique cut portion is formed at the hub mounting end in front of the fan blade. The method of claim 1,
And the fan blade is straight along the entire length of the fan blade. The method of claim 1,
The first ellipse is at least partly formed by the following formula.
x = a (COS (t))-(1)
y = b (SIN (t))-(2)
x and y provide the xy coordinates of the first ellipse, where a = first radius length, b = second radius length, and t = radius of rotation about the origin. 16. The method of claim 15,
The second ellipse is at least partially formed by the following formula.
x ₂ = x (COS (θ))-y (SIN (θ))-(3),
y ₂ = y (COS (θ))-x (SIN (θ))-(4)
x ₂ and y ₂ provides the xy coordinates of the second ellipse, x and y are the same as x and y obtained using equations (1) and (2), and θ is the angle at which the first ellipse is rotated around the origin . 17. The method of claim 16,
Wherein θ is approximately 0.525 radians. The method of claim 1,
The first ellipse and the second ellipse intersect at four intersection points when drawn on a common graph, and the elliptic curvature of the upper surface and the elliptic curvature of the lower surface are respectively the first ellipse and the second ellipse in the area between the pair of intersection points. Fan blade, characterized in that based on the curvature of. A fan blade configured to be mounted to a rotating fan hub,
The fan blade is
An upper surface having an elliptical curvature; And
A lower surface having an elliptical curvature,
The curvature of the upper surface is formed of a first ellipse and the curvature of the lower surface is formed of a second ellipse,
The first ellipse and the second ellipse intersect at four intersections when drawn on a common graph, and the elliptic curvature of the upper surface and the elliptic curvature of the lower surface are respectively the first ellipse and the second ellipse in the area between the pair of intersection points. Fan blade, characterized in that formed in the curvature of. A fan blade configured to be mounted to a rotating fan hub,
The fan blade is
An upper surface having an elliptical curvature; And
A lower surface having an elliptical curvature,
And the curvature of the upper surface is formed of a first ellipse, the curvature of the lower surface is formed of a second ellipse, and the formation of the second ellipse is dependent on the formation of the first ellipse.

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