A FAN BLADE UNIT WITH GURNEY FLAP

FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a fan blade unit for air cooler, industrial fan, table fan, etc., and, in particular to, a fan blade unit having a gurney flap at trailing edge to enhance lift coefficient to improve discharge air velocity.
BACKGROUND AND PRIOR ART:
[002] Generally, air coolers, such as house hold air coolers, industrial air coolers, table fan, computer fan blade requires high lift coefficient to improve air discharge velocity. To improve air discharge velocity, existing design suggests optimizing angle of attack, blade chord length, camber, twist angle, lift angle. Making these changes involve lot of tooling cost and complete design has to be changed.
[003] The prior art document US20180162515A1 assigned to CLAVERHAM LTD, relates to a gurney flap, which comprises an airfoil with a trailing edge and an opening in a surface of the airfoil. The gurney flap includes a first position in which at least a portion of the gurney flap 1extends through the opening and projects outwardly from the airfoil surface, and a second position in which the gurney flap does not project from the airfoil surface or projects outwardly from the airfoil surface to a lesser extent; and a gurney flap actuator for moving the gurney flap between at least the first position and the second position.
[004] Another prior art document US 8,757,557 B2 assigned to CLAVERHAM LTD, relates to a gurney flap assembly, which comprises an actuator, and a flexible body attaching to the actuator, the body having a downwardly depending flap for moving into and out of an airstream in a pressure side of a wing, wherein the flexible body flexes in reaction to motion of the actuator.
[005] There is need in the art to provide improve the air discharge velocity without optimizing the standard blade characteristics, such as angle of attack, blade chord length, camber etc. In the present subject matter provides a simple and effective technical solution for the above mentioned technical objective to improve air discharge velocity that does not increase the complexity and overall manufacturing cost.
OBJECTS OF THE INVENTION:
[006] The principal objective of the present subject matter is to improve the overall performance of fan blade unit.
[007] Another object of the present subject matter is to improve the air discharge velocity of air cooler.
[008] Yet another object of the present subject matter is to provide a gurney flap in the fan blade unit to improve lift to drag ratio which results in more efficient and effective air discharge velocity.
[009] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.
SUMMARY OF THE INVENTION:
[0010] One or more drawbacks of conventional method for scale removal of water heating element in the water geyser, and additional advantages are provided through the method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure
[0011] The present subject matter relates to a fan blade unit having a hub and a plurality of blades that is configured to extend away from the hub. Each blade from the plurality of blades has a leading-edge and a trailing-edge. A gurney flap is projecting perpendicularly from the trailing-edge of each blade from the plurality of blades.
[0012] In an aspect, each blade from the plurality of blades defines a root end and a tip end where the gurney flap is provided in between the root end and the tip end.
[0013] In an aspect, length of the gurney flap is smaller than length of each blade from the plurality of blades.
[0014] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0016] Fig. 1 and 2 illustrate a structure of fan blade unit, in accordance with an embodiment of the present subject matter; and
[0017] Fig. 3 illustrates a structure of blade of fan blade unit as shown in fig. 1, in accordance with the present subject matter.
[0018] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0019] The present subject matter relates to a fan blade unit having a hub and a plurality of blades that is configured to extend away from the hub. Each blade from the plurality of blades has a leading-edge and a trailing-edge. A gurney flap is projecting perpendicularly from the trailing-edge of each blade from the plurality of blades.
[0020] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art and are to be constructed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0021] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0022] Fig. 1-2 illustrate a structure of a fan blade unit, in accordance with the present subject matter. The fan blade unit 200 including a hub 201 and a plurality of blades 202 that is configured to extend away from the hub 201 such that each blade from the plurality blades 202 has a leading edge 202a and a trailing edge 202b. Further, a gurney flap 204 is projecting perpendicularly from the trailing edge 202b of each blade from the plurality blades 202. The gurney flap 204 is integrated at a right angle to the pressure-side surface of the blade and projecting in a range of 1% to 2% of wing chord. The wing chord is distance between the trialing edge and the leading edge. Further, in the uneven shape of the blade, the wing chord may be calculated by Mean Aerodynamic Chord (MAC).
[0023] As shown in the figure 2 and 3, each blade from the plurality of blades 202 (hereinafter single blade can be referred as blade 202) has a root end 202c and a tip end 202d. The root end 202c is connected with the hub 201 and tip end 202d is the distal end of the blade 202. The gurney flap 204 is provided in between the root end 202c and the tip end 202d of the blade 202. As shown in the figure 3, length 204a of the gurney flap 204 is smaller than length 202e of the blade 202.
[0024] In accordance with an embodiment of the present subject matter, the shape and size of the gurney flap 204 can be optimized by using Computational Fluid dynamics (CFD) techniques. The gurney flap 204 in the blade 202 increases the maximum lift coefficient with very little drag penalty. As known that the air flow of the air cooler is directly dependent on lift generated by the blades of the fan blade unit 200.
[0025] With the gurney flap 204, the air throw efficiency of the fan blade unit 200 is increased. In the fan blade unit 200 there are no change apart from addition of gurney flap 204. Other blade characteristics are standard characteristics as exist in the existing fan blade units.
[0026] The gurney flap 204 increases pressure on the pressure side, i.e., trailing edge and decreases pressure on the suction side, i.e., leading edge. Further, the gurney flap 204 helps the boundary layer flow stay attached all the way to the trailing edge on the suction side of the blade.
[0027] In an aspect, the gurney flap 204 increases the maximal lift coefficient (CL,max) and decreases the angle of attack for zero lift. Further, overall lift-to-drag ratio is improved if the flap is sized appropriately, based on the boundary layer thickness. Furthermore, the lift to drag ratio is in range 15 – 65. The fan blade unit 200 has lift coefficient is in range 1.50 to 1.95.
[0028] The gurney flap 204 increases the drag coefficient, that increases the air discharge velocity up to 11.2m/s. The fan blade unit 200 has air discharge velocity in range 8.0 m/s to 11.2 m/s. The fan blade unit 200 has 10.2 m/s average air discharge velocity and 11.2 m/s peak air discharge velocity. With the implementation of the gurney flap 204 in the existing fan blade unit, average air discharge velocity is increased up to 10%.
[0029] Advantages of the present subject matter: The present fan blade unit with the gurney flap is to improve the efficiency of air throw of the blade as compared to the existing design. Also, the present fan blade unit with gurney flap allows very minor change in design which results in low tooling cost.
[0030] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
[0031] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.
[0032] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:

1. A fan blade unit (200) comprising:
a hub (201) at center; and
a plurality of blades (202) extending away from the hub (201), wherein each blade from the plurality blades (202) has a leading edge (202a) and a trailing edge (202b);
characterized in that
a gurney flap (204) projecting perpendicularly from the trailing edge (202b) of each blade from the plurality of blades (202).
2. The fan blade unit (200) as claimed in claim 1, wherein the gurney flap (204) is positioned at a right angle to a pressure side surface of each blade from the plurality of blades (202).
3. The fan blade unit (200) as claimed in claim 1, wherein each blade from the plurality of blades (202) define a root end (202c) and a tip end (202d), the gurney flap (204) is provided in between the root end (202c) and the tip end (202d).
4. The fan blade unit (200) as claimed in claim 1, wherein length (204a) of the gurney flap (204) is smaller than length (202e) of each blade from the plurality of blades (202).
5. The fan blade unit (200) as claimed in claim 1, wherein the gurney flap (204) is projecting in a range of at least 1% to 2% of a wing chord.
6. The fan blade unit (200) as claimed in claim 1, wherein the fan blade unit (200) has lift to drag ratio is in range 15 - 65.
7. The fan blade unit (200) as claimed in claim 1, wherein the fan blade unit (200) has lift coefficient is in range 1.50 to 1.95.
8. The fan blade unit (200) as claimed in claim 1, wherein discharge air velocity of the fan blade unit (200) is in range 8.0 m/s to 11.2 m/s.
9. The fan blade unit (200) as claimed in claim 1, wherein average discharge air velocity of the fan blade unit (200) is 10.2 m/s.
10. The fan blade unit (200) as claimed in claim 1, wherein the gurney flap (204) is integrated with the fan blade unit (200).
11. The fan blade unit (200) as claimed in claim 1, wherein the gurney flap (204) is provided through injection molding process.