Turbine rotor blade

Abstract

A rotor blade assembly for use with a rotating shaft, the rotor blade assembly may comprise a rotor hub coaxially mounted on the rotating shaft, and a plurality of blades connected to and arranged circumferentially around the rotor hub. Each respective blade of the plurality of blades may be mirror-symmetrical with respect to a corresponding plane of symmetry. The corresponding plane of symmetry may extend between a hub-side end and a tip-side end of the respective blade, bisecting the respective blade into two similar portions, wherein each of the respective similar portions comprises a root edge connected to the rotor hub, a trailing edge, a leading edge, and a blade surface extending between the root edge, the trailing edge, the leading edge, and the corresponding plane of symmetry.

Description

Ref- 1403003TURBINE ROTOR BLADETECHNICAL FIELD

[0001] The present disclosure generally relates to turbine blades for generating energy, and more particularly to turbine rotor blades capable of harvesting energy from renewable energy sources such as wind power.BACKGROUND

[0002] The ongoing expansion of civilization has led to a significant global demand for energy, with a particular emphasis on clean sources. Wind turbines are essential in the shift towards cleaner energy sources, offering numerous advantages and some notable challenges. The primary benefits of wind power include its clean and renewable nature, as it generates electricity without burning fuel or emitting pollutants, thereby maintaining a low carbon footprint and aiding in the fight against climate change. Versatility of wind power allows it to be utilized in various settings, including rural areas, coastal communities, and islands with abundant wind resources.

[0003] However, conventional wind power equipment faces challenges such as intermittency, as its availability depends on wind speed and direction, affecting grid stability and reliability. The efficiency and overall performance of wind turbines are greatly influenced by the design choices made for various blade features. Therefore, there is need for turbine rotor blades capable of increasing wind power capture to enhance efficiency and performance.SUMMARY

[0004] This summary is intended to provide an overview of the subject matter of one or more exemplary embodiments, and is not intended to identify essential elements or key elements of the subject matter, nor is it intended to be used to determine the scope of theRef- 1403003 claimed implementations. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. The proper scope of one or more exemplary embodiments may be ascertained from the claims set forth below in view of the detailed description below and the drawings.

[0005] In one general aspect, the present disclosure may describe an exemplary rotor blade assembly for use with an exemplary rotating shaft. In an exemplary embodiment, an exemplary rotor blade assembly may comprise an exemplary rotor hub, and a plurality of exemplary blades. In an exemplary embodiment, the exemplary rotor hub may be coaxially mounted on the exemplary rotating shaft. In one or more exemplary embodiments, the plurality of exemplary blades may be connected to and may be arranged circumferentially around the exemplary rotor hub. In an exemplary embodiment, the plurality of exemplary blades may be arranged equally- spaced around the exemplary rotor hub.

[0006] In one or more exemplary embodiments, each respective exemplary blade of the plurality of exemplary blades may be mirror- symmetrical with respect to a corresponding exemplary plane of symmetry. In an exemplary embodiment, the corresponding exemplary plane of symmetry may extend between an exemplary hub-side end and an exemplary tip-side end of the respective blade, bisecting the respective blade into two exemplary similar portions. In an exemplary embodiment, each respective blade of the plurality of exemplary blades may define an angular distance, a, between their corresponding plane of symmetry and the exemplary rotating shaft such that the angular distance may be defined by the inequality (1): (T< a < 9Cr (1)

[0007] In an exemplary embodiment, each respective blade of the plurality of exemplary blades may define an angular distance, a, between their corresponding plane of symmetry andRef- 1403003 the exemplary rotating shaft such that the angular distance may be defined by the inequality(2):90° < a (2)

[0008] In an exemplary embodiment, each respective blade of the plurality of exemplary blades may define an angular distance, a, between their corresponding plane of symmetry and the exemplary rotating shaft such that the angular distance may be defined by the inequality(3):(T< a < 18cr (3)

[0009] In an exemplary embodiment, each of the respective exemplary similar portions may comprise an exemplary root edge, an exemplary trailing edge, an exemplary leading edge, and an exemplary blade surface. In an exemplary embodiment, the exemplary root edge may be connected to the exemplary rotor hub, wherein the exemplary root edge may define an exemplary first angle, OR, with the corresponding exemplary plane of symmetry. In an exemplary embodiment, the exemplary root edge may comprise an exemplary first linear segment extending from the exemplary first end of the exemplary root edge to an exemplary middle part of the exemplary root edge such that the exemplary first angle is defined between the exemplary first linear segment and the corresponding exemplary plane of symmetry. In an exemplary embodiment, the exemplary first angle may be defined by the Inequality (4):(T< eR < 9Cr (4)

[0010] In an exemplary embodiment, the exemplary middle part of the exemplary root edge having an exemplary curved segment which tangentially extends from the exemplary first linear segment.

[0011] In an exemplary embodiment, the exemplary trailing edge may be disposed farther from the exemplary rotor hub than the exemplary root edge. In an exemplary embodiment, theRef- 1403003 exemplary trailing edge may comprise an exemplary first segment extending between an exemplary first end of the exemplary trailing edge and the corresponding exemplary plane of symmetry, wherein an exemplary second angle, OT, may be defined between the exemplary first segment and the corresponding exemplary plane of symmetry. In an exemplary embodiment, the exemplary second angle may be defined by the Inequality (5):OT < OR (5)

[0012] In an exemplary embodiment, the exemplary second angle may be defined by the Inequality (6):26’< eT< 4 (6)

[0013] In an exemplary embodiment, the exemplary trailing edge may define an exemplary sixth angle, 06, with an exemplary line which is perpendicular to the corresponding exemplary plane of symmetry and passes through the exemplary first end of the exemplary trailing edge. In an exemplary embodiment, the exemplary sixth angle may be defined by the Inequality (7):06 > 51° (7)

[0014] In an exemplary embodiment, the exemplary trailing edge may further comprise an exemplary middle part comprising an exemplary curved segment which tangentially extends from the exemplary first segment of the exemplary trailing edge and proceeds towards the corresponding exemplary plane of symmetry.

[0015] In an exemplary embodiment, the exemplary leading edge may divergently extend from an exemplary first end of the exemplary root edge to the exemplary first end of the exemplary trailing edge, wherein the exemplary leading edge may define an exemplary third angle, e3, with the exemplary trailing edge at the exemplary first end of the exemplary trailing edge. In an exemplary embodiment, the exemplary leading edge may define anRef- 1403003 exemplary fourth angle, e4, with the corresponding exemplary plane of symmetry at the exemplary first end of the exemplary trailing edge. In an exemplary embodiment, the exemplary leading edge may define an exemplary fifth angle, e5, with the corresponding exemplary plane of symmetry at the exemplary first end of the exemplary root edge. In one or more exemplary embodiments, the exemplary third, fourth, and fifth angles may be defined by the Inequality (8): e5 < e4 < e3 (8)

[0016] In an exemplary embodiment, the exemplary third, fourth, and fifth angles may be defined by the Inequalities (9) and (10):4°< e5 < e4 < 26’ (9)95°< e3 < l l l° (10)

[0017] In an exemplary embodiment, the exemplary blade surface may extend between the exemplary root edge, the exemplary trailing edge, the exemplary leading edge, and the corresponding exemplary plane of symmetry. In one or more exemplary embodiments, the exemplary blade surface may define an exemplary curved line disposed within the corresponding exemplary plane of symmetry and extending from the exemplary root edge to the exemplary trailing edge. In one or more exemplary embodiments, the exemplary curved line may comprise at least two exemplary portions comprising an exemplary first inwardly arced portion, and a second inwardly arced portion. In an exemplary embodiment, the exemplary first inwardly arced portion may extend from the exemplary root edge towards the exemplary trailing edge. In an exemplary embodiment, the exemplary first inwardly arced portion may comprise an exemplary first degree of curvature, Pi. In an exemplary embodiment, the exemplary second inwardly arced portion may extend from the exemplary trailing edge towards the exemplary root edge. In an exemplary embodiment, the exemplary secondRef- 1403003 inwardly arced portion may comprise an exemplary second degree of curvature, p2. In an exemplary embodiment, the exemplary first degree of curvature and the exemplary second degree of curvature may be defined by the Inequality (11):Pl < 02 (11)

[0018] In an exemplary embodiment, the exemplary curved line may further comprise an exemplary third inwardly arced portion having an exemplary third degree of curvature, P3, wherein the exemplary third portion tangentially extends from the exemplary first inwardly arced portion to the exemplary second inwardly arced portion.

[0019] In an exemplary embodiment, the exemplary first degree and the exemplary second degree of curvatures corresponding to the exemplary first inwardly arced portion and the exemplary second inwardly arced portion of the exemplary curved line may be defined by the Inequality (12):1°< PI < P2< 47 (12)

[0020] This Summary may introduce a number of concepts in a simplified format; the concepts are further disclosed within the “Detailed Description” section. This Summary is not intended to configure essential / key features of the claimed subject matter, nor is intended to limit the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The novel features which are believed to be characteristic of the present disclosure, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which a presently preferred embodiment of the present disclosure will now be illustrated by way of example. It is expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the presentRef- 1403003 disclosure. Embodiments of the present disclosure will now be described by way of example in association with the accompanying drawings in which:

[0022] FIG. 1A illustrates a perspective view of an exemplary rotor blade assembly, consistent with one or more embodiments of the present disclosure;

[0023] FIG. 2A illustrates a front view of an exemplary blade, consistent with one or more embodiments of the present disclosure;

[0024] FIG. 2B illustrates a front view of an exemplary blade inclined with respect to an exemplary rotating shaft, consistent with one or more embodiments of the present disclosure;

[0025] FIG. 2C illustrates an exemplary configuration of rotor blade assembly, consistent with one or more embodiments of the present disclosure;

[0026] FIG. 2D illustrates another exemplary configuration of rotor blade assembly, consistent with one or more embodiments of the present disclosure;

[0027] FIG. 3A illustrates a detailed view of an exemplary blade, consistent with one or more embodiments of the present disclosure;

[0028] FIG. 3B illustrates a side view of an exemplary blade, consistent with one or more embodiments of the present disclosure;

[0029] FIG. 3C illustrates a top view of an exemplary blade, consistent with one or more embodiments of the present disclosure;

[0030] FIG. 3D illustrates a cross-sectional view of an exemplary blade along line A- A depicted in FIG. 3C, consistent with one or more embodiments of the present disclosure;

[0031] FIG. 3E illustrates a cross-sectional view of an exemplary blade along line B- B depicted in FIG. 3D, consistent with one or more embodiments of the present disclosure; andRef- 1403003

[0032] FIG. 4 illustrates a schematic view of external loads applied to an exemplary blade, consistent with one or more embodiments of the present disclosure.DETAILED DESCRIPTION

[0033] In the following detailed description, numerous specific details are set forth by way of examples to provide a thorough understanding of the relevant teachings related to the exemplary embodiments. However, it should be apparent that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and / or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.

[0034] The following detailed description is presented to enable a person skilled in the art to make and use the methods and devices disclosed in one or more exemplary embodiments of the present disclosure. For purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that these specific details are not required to practice the disclosed exemplary embodiments. Descriptions of specific exemplary embodiments are provided only as representative examples. Various modifications to the exemplary implementations will be plain to one skilled in the art, and the general principles defined herein may be applied to other implementations and applications without departing from the scope of the present disclosure. The present disclosure is not intended to be limited to the implementations shown, but is to be accorded the widest possible scope consistent with the principles and features disclosed herein.

[0035] Referring now to the figures, FIG. 1A illustrates a perspective view 101 of an exemplary rotor blade assembly 102, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, rotor blade assembly 102 may employ an exemplary rotating shaft 104 which is connected to an exemplary gearbox 106 for generating variousRef- 1403003 speeds and torques as rotor blade assembly 102 rotates about rotating shaft 104. In an exemplary embodiment, gearbox 106 may be connected to an exemplary generator 108 through an exemplary secondary shaft 110 for producing electrical energy from rotation of rotor blade assembly 102 about rotating shaft 104.

[0036] In one or more exemplary embodiments, an exemplary coordinate system 100 for rotor blade assembly 102, shown in FIG. 1, is represented by three mutually perpendicular exemplary axes 112, 114, and 116. In an exemplary embodiment, an exemplary vertical axis 112, also called rotational axis, or z-axis, aligns with rotating shaft 104. An exemplary radial axis 114, also called axis of symmetry, or r-axis, is an axis drawn through an exemplary blade of rotor blade assembly 102, from an exemplary hub-side end to an exemplary tip-side end thereof. An exemplary transverse axis 116, also called e-axis, is an axis running from an exemplary backside to an exemplary pressure side of the exemplary blade of rotor blade assembly 102.

[0037] FIG. 2A illustrates a front view 201 of an exemplary blade 204, and FIG. 2B illustrates a front view 203 of an exemplary blade 204 inclined with respect to an exemplary rotating shaft 104, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, rotor blade assembly 102 may comprise an exemplary rotor hub (e.g., rotor hub 206a or 206b), and a plurality of exemplary blades. In an exemplary embodiment, rotor hub 206a may be coaxially mounted on rotating shaft 104 (i.e., rotating shaft 104 and rotor hub (e.g., rotor hub 206a or 206b) are coaxial with respect to axis of rotation 214 which aligns with z-axis). In one or more exemplary embodiments, the plurality of exemplary blades may be connected to rotor hub (e.g., rotor hub 206a or 206b). In an exemplary embodiment, as shown in FIG. 1, each blade 204 of rotor blade assembly 102 may be arranged circumferentially around rotor hub (e.g., rotor hub 206a pr 206b). In an exemplaryRef- 1403003 embodiment, the plurality of exemplary blades may be arranged equally-spaced around rotor hub (e.g., rotor hub 206a or 206b).

[0038] In an exemplary embodiment, with continued reference to FIGs. 2A-2B, each blade 204 of rotor blade assembly 102 may span between an exemplary hub-side end 208 and an exemplary tip-side end 210 (i.e., align r-axis). In an exemplary embodiment, each blade 204 may be mirror- symmetrical with respect to an exemplary plane of symmetry 212 which extends between hub- side end 208 and tip- side end 210 of blade 204. In an exemplary embodiment, plane of symmetry 212 may substantially bisect blade 204 into two exemplary substantially similar portions (i.e., portions 204a and 204b). In an exemplary embodiment, blade 204 may define an exemplary angle a with axis of rotation 214. In an exemplary embodiment, angle a may be defined between plane of symmetry 212 of blade 204 and rotating shaft 104 (i.e., axis of rotation 214). In an exemplary embodiment, as shown in FIG. 2A, angle a may be substantially equal to or less than 90 degrees (i.e., O’ < a < 90). In an exemplary embodiment, as shown in FIG. 2B, angle a may be greater than or equal to 90 degrees (i.e., 90s< a). In an exemplary embodiment, angle a may be in a range of 0 degree to 180 degrees (i.e., O’ < a < 180). In an exemplary embodiment, angle a may be substantially equal to 120 degrees (i.e., a = 120).

[0039] FIG. 2C illustrates an exemplary configuration 205 of rotor blade assembly 102, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, as shown in FIG. 2C, rotor blade assembly 102 may comprise at least two exemplary sets of rotor blade assembly 102, employed to generate more electrical power when compared to usage of a singular set of rotor blade assembly 102. In an exemplary embodiment, one exemplary set may comprise blades in non-inclined position and another exemplary set may comprise blades in inclined positions with respect to axis of rotation 214. In an exemplaryRef- 1403003 embodiment, exemplary sets of rotor blade assembly may be connected to same rotating shaft (e.g., shaft 104) via rotor hubs 206a and / or 206b. In an exemplary embodiment, rotating shaft 104 may comprise two or more sections having similar or various radii.

[0040] FIG. 2D illustrates another exemplary configuration 207 of rotor blade assembly 102, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, rotor blade assembly 102 may comprise blades (e.g., blade 204) in both inclined and non-inclined positions with respect to axis of rotation 214. In an exemplary embodiment, blades in both inclined and non-inclined positions may be arranged circumferentially around an exemplary rotor hub 206c. In an exemplary embodiment, blades in in both inclined and non-inclined positions may equidistantly be mounted around rotor hub 206c.

[0041] FIG. 3A illustrates a detailed view 301 of an exemplary blade 204, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, each blade 204 of rotor blade assembly 102 may comprise an exemplary trailing edge 308, at least two exemplary leading edges (i.e., leading edges 314a and 314b), an exemplary root edge 316, and an exemplary blade surface 317. In an exemplary embodiment, root edge 316 may be connected to rotor hub 206a. In an exemplary embodiment, root edge 316 may be disposed at hub-side end of blade 204 and trailing edge 308 may be disposed at tip-side end of blade 204. In an exemplary embodiment, blade surface 317 may span between trailing edge 308, root edge 316, and leading edges 314a and 314b. It is appreciated that rotor hub 206b can be employed instead of rotor hub 206a without altering exemplary essential features of blade 204 as will be described here.

[0042] In an exemplary embodiment, trailing edge 308 may be disposed farther from rotor hub 206a than root edge 316. In an exemplary embodiment, trailing edge 308 may extendRef- 1403003 between an exemplary first end 310a and second end 310b. In an exemplary embodiment, root edge 316 may span between an exemplary first end 318a and an exemplary second end 318b. In an exemplary embodiment, leading edges 314a and 314b may span between trailing edge 308 and root edge 316. In an exemplary embodiment, first leading edge 314a and second leading edge 314b may diverge from each other. In an exemplary embodiment, first leading edge 314a may extend from first end 318a of root edge 316 to first end 310a of trailing edge 308 such that at trailing edge 308, first leading edge 314a may deviate further from plane of symmetry 212 compared to its deviation at root edge 316. In an exemplary embodiment, second leading edge 314b may extend from second end 318b of root edge 316 to second end 310b of trailing edge 308 such that deviation of second leading edge 314b from plane of symmetry 212 may tend to be more pronounced at trailing edge 308 than at root edge 316.

[0043] In an exemplary embodiment, with continued reference to FIG. 3A, blade surface 317 may define an exemplary curved line 320 disposed within plane of symmetry 212 and extending from root edge 316 to trailing edge 308. In an exemplary embodiment, curved line320 may intersect with trailing edge 308 at an exemplary transition point 312. In an exemplary embodiment, transition point 312 may be an exemplary apex of trailing edge 308. In an exemplary embodiment, blade surface 317 may separate blade 204 into an exemplary back side321 and an exemplary pressure side 322. In an exemplary embodiment, pressure side 322 is an exemplary side of blade 204 which is capable of effectively capturing an exemplary fluid flow 323 to produce an exemplary torque required for generating rotational motion of rotor blade assembly 102. In an exemplary embodiment, fluid flow 323 may be an exemplary air flow, so rotor blade assembly 102 is used as an exemplary wind turbine.

[0044] FIG. 3B illustrates a side view 303 of an exemplary blade 204, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, plane ofRef- 1403003 symmetry 212 may bisect each respective trailing edge 308, root edge 316, and blade surface 317 into two substantially similar sections. In an exemplary embodiment, due to blade’s symmetry, first leading edge 314a and second leading edge 314b may have equal lengths. In one or more exemplary embodiments, curved line 320 may comprise at least two exemplary portions comprising an exemplary first inwardly arced portion 324, and an exemplary second inwardly arced portion 326 (i.e., both portions may bend toward pressure side 322 of blade 204 such that both portions may define concave segments with respect to back side 321 of blade 204). In an exemplary embodiment, first inwardly arced portion 324 may extend from root edge 316 towards trailing edge 308. In an exemplary embodiment, first inwardly arced portion 324 may be an exemplary arc of an exemplary circle having an exemplary radius Ri. In an exemplary embodiment, first inwardly arced portion 324 may comprise an exemplary first degree of curvature, Pi.

[0045] In an exemplary embodiment, with continued reference to FIG. 3A, second inwardly arced portion 326 may extend from trailing edge 308 towards root edge 316. In an exemplary embodiment, second inwardly arced portion 326 may be an exemplary arc of an exemplary circle having an exemplary radius R2. In an exemplary embodiment, second inwardly arced portion 326 may comprise an exemplary second degree of curvature, P2. In an exemplary embodiment, first degree of curvature may measure less than or equal to second degree of curvature (i.e., Pi < P2). In an exemplary embodiment, first degree of curvature may be greater than 1 degree (i.e., 1° < Pi). In an exemplary embodiment, first degree of curvature may be in a range of 1 degree to 17 degrees (i.e., 1° < Pi < 17°). In an exemplary embodiment, second degree of curvature may be less than 47 degrees (i.e., P2 < 47). In an exemplary embodiment, second degree of curvature may be in a range of 31 degrees to 47 degrees (i.e., 31° < P2 < 47). In an exemplary embodiment, first degree of curvature may be greater than 1Ref- 1403003 degree and less than or equal to second degree of curvature, and second degree of curvature may be less than 47 degrees (i.e., 1°< Pi < P2 < 47°). In an exemplary embodiment, curved line 320 may further comprise an exemplary third inwardly arced portion 328 having an exemplary third degree of curvature, P3, wherein third inwardly arced portion 328 tangentially extends from first inwardly arced portion 324 to second inwardly arced portion 326.

[0046] In an exemplary embodiment, root edge 316 may define an exemplary first angle, OR, with plane of symmetry 212 (as will be shown in FIG. 3E). In an exemplary embodiment, trailing edge 308 may define an exemplary second angle, OT, with plane of symmetry 212 (as will be shown in FIG. 3D). In an exemplary embodiment, an exemplary tangent 330 of trailing edge 308 at each respective first end 310a and second end 310b may define an exemplary third angle, 03, with an exemplary tangent plane 332 to corresponding leading edges 314a and 314b. In an exemplary embodiment, third angle 03, may be in a range of 95 degrees to 111 degrees (i.e., 95° < 03 < 111°).

[0047] FIG. 3C illustrates a top view 305 of an exemplary blade 204, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, each respective leading edge 314a and 314b may define an exemplary fourth angle, 04, with r-axis (or with plane of symmetry 212 which is parallel with r-axis) at corresponding first end 310a and second end 310b of trailing edge 308 (e.g., fourth angle is an angle between an exemplary line 338, tangent to second leading edge 314b at second end 310b of trailing edge 308, and r- axis). In an exemplary embodiment, fourth angle may be less than 26 degrees. In an exemplary embodiment, fourth angle may be between 10 degrees and 26 degrees (i.e., 1(T< 04 < 26).

[0048] In an exemplary embodiment, each respective leading edge 314a and 314b may define an exemplary fifth angle, 05, with r-axis (or with plane of symmetry 212 which is parallel with r-axis) at corresponding first end 318a and second end 318b of root edge 316 (e.g., fifthRef- 1403003 angle is an angle between an exemplary line 340, tangent to second leading edge 314b at second end of root edge 316, and r-axis). In an exemplary embodiment, fifth angle may be greater than 4 degrees (i.e., 4° < es). In an exemplary embodiment, fifth angle may be in a range of 4 degrees to 20 degrees (i.e., 4°< es < 20). In one or more exemplary embodiments, fourth angle may be greater than or equal to fifth angle es < 04. In an exemplary embodiment, fourth angle may be greater than fifth angle greater than 4 degrees, and fourth angle may also be less than 26 degrees (i.e., 4°< os < 04 < 26). In an exemplary embodiment, third angle may be greater than or equal to fourth angle, and fourth angle may be greater than or equal to fifth angle (i.e., 05 < 04 < 03). It is appreciated that although FIG. 3C illustrates fourth and fifth angles specifically for second leading edge 314b, similar angles may also be defined for first leading edge 314a, because blade 204 is mirror- symmetrical with respect to plane of symmetry 212.

[0049] FIG. 3D illustrates a cross-sectional view 307 of an exemplary blade 204 along line A-A depicted in FIG. 3C, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, plane of symmetry 212 may divide trailing edge 308 into two substantially similar sections which may also be referred to as trailing edge. In an exemplary embodiment, trailing edge 308 may comprise an exemplary first segment 308a and an exemplary second segment 308b. In an exemplary embodiment, first segment 308a and second segment 308b may extend from corresponding first end 310a and second end 310b of trailing edge 308 defining second angle, OT, relative to plane of symmetry 212, so first segment 308a and second segment 308b may have an angular distance with each other which is twice second angle (i.e., angular distance between an exemplary line 342, tangent to first segment 308a, and an exemplary line 344, tangent to second segment 308b equals to 2OT). In an exemplary embodiment, trailing edge 308 may further comprise an exemplary middle part 346 comprising an exemplary curved segment which extends between first and second segmentsRef- 1403003308a and 308b of trailing edge 308. In an exemplary embodiment, plane of symmetry 212 may bisect middle part 346 into two substantially similar sections. In an exemplary embodiment, due to blade’ s symmetry, first and second segments 308a and 308b may be substantially similar and have substantially equal lengths. In an exemplary embodiment, each of first and second segments 308a and 308b may comprise an exemplary straight line which is tangent to middle part 346 at exemplary intersection with it. In an exemplary embodiment, second angle may be in a range of 26 degrees to 42 degrees (i.e., 26s< er < 42).

[0050] In an exemplary embodiment, each first segment 308a and second segment 308b of trailing edge 308 may define an exemplary sixth angle, 06, with an exemplary plane 332 which passes through both first end 310a and second end 310b of trailing edge 308. In an exemplary embodiment, tangent plane 332 may be perpendicular to plane of symmetry 212. In an exemplary embodiment, sixth angle may be greater than or equal to 51 degrees (i.e., 06 > 51°). It is appreciated that although FIG. 3D illustrates second and sixth angles specifically for first segment 308a of trailing edge 308, similar angles may also be defined for second segment 308b, because blade 204 is mirror- symmetric al with respect to plane of symmetry 212.

[0051] FIG. 3E illustrates a cross-sectional view 309 of an exemplary blade 204 along line B-B depicted in FIG. 3D, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, root edge 316 may comprise an exemplary first linear segment 316a and an exemplary second linear segment 316b. In an exemplary embodiment, root edge 316 may further comprise an exemplary middle part 348 which is tangent to both first and second linear segments 316a and 316b at exemplary intersections with them. In an exemplary embodiment, middle part 348 may comprise an exemplary curved segment. In an exemplary embodiment, each first and second linear segments 316a and 316b may define an exemplary first angle, OR, with plane of symmetry 212. In an exemplary embodiment, firstRef- 1403003 linear segment 316a and second linear segment 316b may extend from respective first end 318a and second end 318b of root edge 316 to middle part 348 thereof. In an exemplary embodiment, first angle may be between 0 and 90 degrees (i.e., O’ < OR < 90). In an exemplary embodiment, first angle may be greater than second angle (i.e., OT < OR). It is appreciated that although FIG. 3E illustrates first angle specifically for first linear segment 316a of root edge 316, similar angle may also be defined for second linear segment 316b, because blade 204 is mirror- symmetrical with respect to plane of symmetry 212.

[0052] FIG. 4 illustrates a schematic view 401 of external loads (e.g., external loads Fi, F2, Fi 1, F22) applied to an exemplary blade 204, consistent with one or more embodiments of the present disclosure. In an exemplary embodiment, when blade 204 is exposed to fluid flow 323 (e.g., air flow), due to an exemplary concave shape of pressure side 322 of blade 204 exemplary forces or loads (e.g., external loads Fi, F2, Fn, F22) are exerted to blade 204 in three mutually perpendicular directions along r-axis and e-axis (as shown in FIG. 4) and z-axis (not shown in figures, but it should be appreciated that because of three dimensional structure of blade 204, some external loads may have three components along said axes). In an exemplary embodiment, external loads (e.g., external loads Fi, F2, Fn, F22) may produce exemplary torques about rotating shaft 104, resulting in rotation of rotor blade assembly 102 about rotating shaft 104. In an exemplary embodiment, every external load (e.g., external loads Fi, F2, Fn, F22) having a distance (e.g., distances Di, D2, Dimax, D2max) with rotating shaft 104 may play a role in generation of torques. In one or more exemplary embodiments, curvatures of blade surface 317 (e.g., degree of curvatures Pi, P2, P3), specifically within plane of symmetry 212, lead to generation of greater torques when compared to an exemplary blade without such curvatures.Ref- 1403003

[0053] In one or more exemplary embodiments, blades (e.g., blade 204) may be manufactured from various materials. In an exemplary embodiment, blade 204 may be manufactured from solid materials such as aluminum, steel, titanium, composite materials, ceramic matrix composites, etc, or any materials known for use in manufacturing turbine blades such as, but are not limited to, U-500, Rene 77, Rene N5, Rene N6, PWA1484, CMSX-4, CMSX-10, Inconel, GTD-111, EPM-102, Nominic 80a, Niminic 90, Nimonic 105, Nimonic 105 and Nimonic 263. In one or more exemplary embodiments, blades (e.g., blade 204) may be manufactured using any known methods such as, but not limited to, casting, machining, extrusion.

[0054] It is appreciated by a person having ordinary skill in the art that all features described above through FIGs. 1-4 for blade 204 connected to rotating shaft 104 via rotor hub 206a can also be defined for an exemplary blade connected to rotating shaft 104 in an inclined position via rotor hub 206b or 206c.

[0055] While the foregoing has described what are considered to be the best mode and / or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.

[0056] Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.Ref- 1403003

[0057] The scope of protection is limited solely by the claims that now follow. That scope is intended and should be interpreted to be as broad as is consistent with the ordinary meaning of the language that is used in the claims when interpreted in light of this specification and the prosecution history that follows and to encompass all structural and functional equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirement of Sections 101, 102, or 103 of the Patent Act, nor should they be interpreted in such a way. Any unintended embracement of such subject matter is hereby disclaimed.

[0058] Except as stated immediately above, nothing that has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is or is not recited in the claims.

[0059] It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. Relational terms such as first and second and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. An element proceeded by “a” or “an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0060] It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study, except where specific meanings have otherwise been set forth herein. Relational terms such as “first” and “second” and the like may be used solely toRef- 1403003 distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0061] The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it may be seen that various features are grouped together in various implementations. This is for purposes of streamlining the disclosure, and is not to be interpreted as reflecting an intention that the claimed implementations require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed implementation. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

[0062] While various implementations have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more implementations and implementations are possible that are within the scope of the implementations. Although many possible combinations of features are shown in the accompanying figures and discussed in this detailed description, many other combinations of the disclosed features are possible. Any feature of any implementation may be used in combination with or substituted for any other feature or element in any other implementation unless specifically restricted. Therefore, it will be understood that any of the features shown and / or discussed in the present disclosure may be implemented together in any suitable combination. Accordingly, the implementations are not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.

Claims

Ref- 1403003What is claimed is:

1. A rotor blade assembly for use with a rotating shaft, the rotor blade assembly comprising: a rotor hub coaxially mounted on the rotating shaft; a plurality of blades connected to and arranged circumferentially around the rotor hub, each respective blade of the plurality of blades being mirror-symmetrical with respect to a corresponding plane of symmetry, the corresponding plane of symmetry extending between a hubside end and a tip- side end of the respective blade, bisecting the respective blade into two similar portions, wherein each of the respective similar portions comprises: a root edge connected to the rotor hub, the root edge making a first angle, OR, with the corresponding plane of symmetry; a trailing edge disposed farther from the rotor hub than the root edge, the trailing edge comprising a first segment extending between a first end of the trailing edge and the corresponding plane of symmetry, wherein a second angle, er, is defined between the first segment and the corresponding plane of symmetry, wherein the second angle is defined by the inequality: er < OR; a leading edge divergently extending from a first end of the root edge to the first end of the trailing edge, wherein the leading edge makes a third angle, 03, with the trailing edge at the first end of the trailing edge, a fourth angle, 04, with the corresponding plane of symmetry at the first end of the trailing edge, and a fifth angle, 05, with the corresponding plane of symmetry at the first end of the root edge, such that the third, fourth, and fifth angles are defined by the inequality: os < 04 < 03; andRef- 1403003 a blade surface extending between the root edge, the trailing edge, the leading edge, and the corresponding plane of symmetry, wherein: the blade surface defines a curved line disposed within the corresponding plane of symmetry and extending from the root edge to the trailing edge; and the curved line comprises at least two portions comprising: a first inwardly arced portion extending from the root edge towards the trailing edge, the first inwardly arced portion comprising a first degree of curvature, Pi; and a second inwardly arced portion extending from the trailing edge towards the root edge, the second inwardly arced portion comprising a second degree of curvature, P2, wherein the first degree of curvature and the second degree of curvature is defined by the inequality:Pi < P2.

2. The rotor blade assembly of claim 1, wherein the plurality of blades are arranged equally-spaced around the rotor hub.

3. The rotor blade assembly of claim 1, wherein the root edge comprises a first linear segment extending from the first end of the root edge to a middle part of the root edge such that the first angle is defined between the first linear segment and the corresponding plane of symmetry, the first angle is defined by the inequality: cr<eR<9cr.

4. The rotor blade assembly of claim 3, wherein the middle part of the root edge having a curved segment which tangentially extends from the first linear segment.

5. The rotor blade assembly of claim 1, wherein the second angle is defined by the inequality:Ref- 140300326’< eT< 42>.

6. The rotor blade assembly of claim 1, wherein the third, fourth, and fifth angles are defined by the inequalities:4° < os < 04 < 26°; and95°< o3< 111°.

7. The rotor blade assembly of claim 1, wherein the trailing edge makes a sixth angle, ©6, with a line which is perpendicular to the corresponding plane of symmetry and passes through the first end of the trailing edge.

8. The rotor blade assembly of claim 7, wherein the sixth angle is defined by the inequality:06 > 5 1°.

9. The rotor blade assembly of claim 1, wherein the trailing edge further comprises a middle part comprising a curved segment which tangentially extends from the first segment of the trailing edge and proceeds towards the corresponding plane of symmetry.

10. The rotor blade assembly of claim 1, wherein the first degree and the second degree of curvatures corresponding to the first inwardly arced portion and the second inwardly arced portion of the curved line are defined by the inequality:1°< PI < P2< 47.

11. The rotor blade assembly of claim 1, wherein the curved line further comprises a third inwardly arced portion having a third degree of curvature, P3, wherein the third inwardly arced portion tangentially extends from the first inwardly arced portion to the second inwardly arced portion.

12. The rotor blade assembly of claim 1, wherein each respective blade of the plurality of blades defines an angular distance, a, between their corresponding plane of symmetry and the rotating shaft such that the angular distance is defined by the inequality: cr< a < 9cr.Ref- 140300313. The rotor blade assembly of claim 1, wherein each respective blade of the plurality of blades defines an angular distance, a, between their corresponding plane of symmetry and the rotating shaft such that the angular distance is defined by the inequality:90s< a.

14. The rotor blade assembly of claim 1, wherein each respective blade of the plurality of blades defines an angular distance, a, between their corresponding plane of symmetry and the rotating shaft such that the angular distance is defined by the inequality:Cf< a < 18(T.

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