Aerodynamic rotor blade

Abstract

The invention is related to a rotor blade for the generation of electrical power. The rotor blade transforms the kinetic energy of a fluid, into rotational movement of a mechanical shaft. The shape of the rotor blade is characterized in that, along an axis, it is longitudinally bound by a root (a) and a tip (b), which are connected through multiples curved segments, called neutral sectional axes [En.sub.i]. All [En.sub.i] generate a continuous or discontinuous curvature called Primary Neutral Axis [En]. The point corresponding to a leading edge and a trailing edge, configure an airfoil [PA.sub.ij]. The curvature of the blade (e) has an arch of length L, and is defined by the neutral sectional axes [En.sub.i]. The blade (e) is defined by at least one continuous curved section called primary neutral axis [En] having a length [L.sub.n]. The blade's shape has a variable cross section along the Primary Neutral Axis [En].

Claims

1. A blade for the generation of electrical power, from the transformation of kinetic energy of a fluid in rotation movement of the blade (e), wherein said movement is transmitted to a rotation axis coupled to said blade (e) located in an orthogonal framework of clearance planes formed by Cartesian axes [{right arrow over (X)}.sub.0], [{right arrow over (Y)}.sub.0] and [{right arrow over (Z)}.sub.0], wherein: the rotation axis is coaxial relative to axis [{right arrow over (Z)}.sub.0]; the origin of the orthogonal framework of clearance planes formed by Cartesian axes [{right arrow over (X)}.sub.0], [{right arrow over (Y)}.sub.0] and [{right arrow over (Z)}.sub.0] is located at the rotation axis and at the point wherein the rotation axis is coupled to the blade (e); the blade (e) extends along axis [{right arrow over (Z)}.sub.0], longitudinally bound by a root (a) and a tip (b), wherein root (a) is located by an auxiliary reference framework {right arrow over (X)}.sub.1{right arrow over (Y)}.sub.1{right arrow over (Z)}.sub.1 which is parallel to the orthogonal framework of clearance planes formed by Cartesian axes [{right arrow over (X)}.sub.0], [{right arrow over (Y)}.sub.0] and [{right arrow over (Z)}.sub.0]; the root (a) and the tip (b) are connected through a series of sectional and constant curvatures called sectional neutral axes [En.sub.i], which generate a continuous or discontinuous primary curvature called a primary neutral axis [En]; the blade (e) has a cross-section limited by a leading edge (f) and a trailing edge (d), which upon joining leading edge (f) and the trailing edge (d) by means of continuous curves, configure an airfoil [PA.sub.ij] having a bottom curve and a top curve; the curvature of the blade (e) has a length L from the root (a) to the tip (b), which is between 0.01 m and 30 m, said curvature is formed by joining a series of points [Pc.sub.ij], which are constructed over the bottom curve of the airfoil [PA.sub.ij], at a distance of c/4 from the leading edge (f), where c is the chord length of the airfoil [PA.sub.ij]; the origin of the framework {right arrow over (X)}.sub.1{right arrow over (Y)}.sub.1{right arrow over (Z)}.sub.1 is located in the point wherein said primary neutral axis [En] crosses the airfoil [PA.sub.ij] at the root (a); the blade's shape comprises a first geometrical variation corresponding to a change in the chord length c of the airfoil [PA.sub.ij] along the primary neutral axis [En]; the blade's shape comprises a second geometrical variation corresponding to an inclination varying along the primary neutral axis [En], said inclination is measured as a function of an inclination angle .sub.ij formed between the chord of each airfoil [PA.sub.ij] and an axis u, wherein the axis u is perpendicular to a plane [P], and the plane [P] coincides with the {right arrow over (X)}.sub.0{right arrow over (Z)}.sub.0 plane and intersects the primary neutral axis [En] at point [Pc.sub.ij]; and said inclination angle .sub.ij ranges between 31.sub.ij30 at the root (a) and between 44.sub.ij16 at the tip (b).

2. The blade (e) according to claim 1, wherein the blade (e) comprises three division sections of the primary neutral axis [En], called the first division section En.sub.1, the second division section En.sub.2 and the third division section En.sub.3, wherein: first division section En.sub.1 comprises a first sectional neutral axis [En.sub.1] and has a length L.sub.1, which begins at the root (a) and ends at a point (2) located over the primary neutral axis [En], limited to a range between 0.15*LL.sub.10.25*L, second division section En.sub.2 comprises a second sectional neutral axis [En.sub.2] and has a length L.sub.2, which begins at point (2) and ends at a point (3) located over the primary neutral axis [En], limited to a range between 0.3*LL.sub.20.5*L, third division section En.sub.3 comprises a third sectional neutral axis [En.sub.3] and has a length L.sub.3, which begins at point (3) and ends at the tip (b), limited to a range between 0.3*LL.sub.30.5*; and wherein the first division section En.sub.1 is tangent to the second division section En.sub.2 at point (2), and the second division section En.sub.2 is tangent to the third division section En.sub.3 at point (3).

3. The blade (e) according to claim 2, wherein the chord length c ranges between 0.05*Lc.sub.110.3*L at the root (a) and between 0.01*Lc.sub.330.3*L at the tip (b).

4. The blade (e) according to claim 2, wherein L.sub.1 is 20% of L, L.sub.2 is 40% of L, and L.sub.3 is 40% of L.

5. The blade (e) according to claim 2, wherein: the first division section En.sub.1 corresponds to the root zone, from which the blade attaches to a horizontal rotation axis, maintaining throughout the first division section En.sub.1 sweep the shape of its airfoils [PA.sub.ij]; said root zone is a constant curve having a constant bending radius Rp.sub.1, which provides a focus located on plane [P] at a distance bound by a range between 1.3*L.sub.1Rp.sub.157*L.sub.1; a first plane A is located at the root (a) and is perpendicular to the sectional neutral axis [En.sub.1], said plane A provides an angle {right arrow over (X)}{right arrow over (Y)}.sub.1 with plane {right arrow over (X)}.sub.1 {right arrow over (Y)}.sub.1 in the range 0{right arrow over (X)}{right arrow over (Y)}.sub.190; said root zone comprises at least three (3) equidistant airfoils PA.sub.11, PA.sub.12 and PA.sub.13, wherein each of these airfoils is located on a plane perpendicular to the sectional neutral axis [En.sub.1], the first plane A located at the root (a) corresponds to airfoil PA.sub.11; a second plane B located on the sectional neutral axis [En.sub.1] at an intermediate point between the root (a) and point (2) belongs to the airfoil PA.sub.12; and a third plane D located at point (2) corresponds to the airfoil PA.sub.13, said sectional neutral axis [En.sub.1] corresponds to joining points Pc.sub.11, Pc.sub.12 and Pc.sub.13 located at a distance of c/4 from the leading edge (f) over the bottom curve of their corresponding airfoils PA.sub.11, PA.sub.12 and PA.sub.13 at planes A, B and D, respectively; the transverse length of said root zone provides progressive and regressive changes or combinations thereof of the chord length c, ranging between 0.05*Lc.sub.110.3*L; 0.046*Lc.sub.120.3*L and 0.042*Lc.sub.130.3*L; each airfoil [PA.sub.ij] making part of the root zone has an inclination angle .sub.ij (.sub.11, .sub.12 and .sub.13, respectively), wherein the inclination angle .sub.ij at the root (a) ranges between 31.sub.1130 and the inclination angle .sub.ij at point (2) ranges between 34.sub.13105.

6. The blade (e) according to claim 5, wherein said angle {right arrow over (X)}{right arrow over (Y)}.sub.1, with plane {right arrow over (X)}.sub.1{right arrow over (Y)}.sub.1 ranges between 0{right arrow over (X)}{right arrow over (Y)}.sub.140.

7. The blade (e) according to claim 6, wherein said angle {right arrow over (X)}{right arrow over (Y)}.sub.1 with plane {right arrow over (X)}.sub.1{right arrow over (Y)}.sub.1 ranges between 10{right arrow over (X)}{right arrow over (Y)}.sub.120.

8. The blade (e) according to claim 5, wherein said chord length c undergoes a progressive change as it moves away from the root (a), said chord length c having a value of 0.082*L, 0.092*L, and 0.099*L, for airfoils PA.sub.11, PA.sub.12 and PA.sub.13, respectively.

9. The blade (e) according to claim 5, wherein the inclination angle .sub.ij at the root (a) ranges between 5.sub.1125 and the inclination-angle .sub.ij at point (2) ranges between 1.sub.1319.

10. The blade (e) according to claim 2, wherein: the second division section En.sub.2 corresponds to the internal zone, maintaining throughout its sweep the shape of its airfoils [PA.sub.ij]; said internal zone is a constant curve having a constant bending radius Rp.sub.2 which has a focus located on plane [P] at a distance bound by a range 1*L.sub.2Rp.sub.25*L.sub.2; said internal zone comprises at least three (3) equidistant airfoils PA.sub.21, PA.sub.22 and PA.sub.23, wherein each of these airfoils is located on a plane perpendicular to the sectional neutral axis [En.sub.2], a first plane E located at point (2) corresponds to airfoil PA.sub.21; a second plane F located on the sectional neutral axis [En.sub.2] at an intermediate point between point (2) and point (3) belongs to the airfoil PA.sub.22; and a third plane G located at point (3) corresponds to the airfoil PA.sub.23; said sectional neutral axis [En.sub.2] corresponds to joining points Pc.sub.21, Pc.sub.22 and Pc.sub.23 located at a distance of c/4 from the leading edge (f) over the bottom curve of their corresponding airfoils PA.sub.21, PA.sub.22 and PA.sub.23 at planes E, F and G, respectively; the transverse length of this internal zone provides progressive and regressive changes or combinations thereof of the chord length c, ranging between 0.042*Lc.sub.210.3*L, 0.034*Lc.sub.220.3*L and 0.026*Lc.sub.230.3*L; each airfoil [PA.sub.ij] making part of the internal zone has an inclination angle .sub.ij (.sub.21, .sub.22 and .sub.23, respectively), wherein the inclination angle .sub.ij at point (2) ranges between 34.sub.21105 and the inclination angle .sub.ij at point (3) ranges between 41.sub.2360.

11. The blade (e) according to claim 10, wherein said transverse length of said internal zone comprises a first progressive change in the length of chord length c from point (2) up to an inflection point located on plane F at the middle of the sectional neutral axis [En.sub.2], and a second regressive change in the length of chord length c until point (3), said chord length c having a value of 0.099*L, 0.104*L, and 0.094*L, for airfoils PA.sub.21, PA.sub.22 and PA.sub.23, respectively.

12. The blade (e) according to claim 10, wherein the inclination angle .sub.ij at point (2) ranges between 1.sub.2119 and the inclination angle .sub.ij at point (3) ranges between 5.sub.2313.

13. The blade (e) according to claim 2, wherein: the third division section En.sub.3 corresponds to the external zone, maintaining throughout its sweep the shape of its airfoils [PA.sub.ij]; said external zone is a constant curve having a constant bending radius Rp.sub.3, which has a focus located on plane [P] at a distance bound by a range between 1*L.sub.3 Rp.sub.312*L.sub.3; said external zone comprises at least three (3) equidistant airfoils PA.sub.31, PA.sub.32 and PA.sub.33, wherein each of these airfoils is located on a plane perpendicular to the sectional neutral axis [En.sub.3], a first plane H located at point (3) corresponds to airfoil PA.sub.31, a second plane I located on the sectional neutral axis [En.sub.3] at an intermediate point between point (3) and the tip (b) belongs to the airfoil PA.sub.32, and a third plane J located at the tip (b) corresponds to the airfoil PA.sub.33; said sectional neutral axis [En.sub.3] corresponds to joining points Pc.sub.31, Pc.sub.32 and Pc.sub.33 located at a distance of c/4 from the leading edge (f) over the bottom curve of their corresponding airfoils PA.sub.31, PA.sub.32 and PA.sub.33 at planes H, I and J, respectively; the transverse length of this external zone provides progressive and regressive changes or combinations thereof of the chord length c, ranging between 0.026*Lc.sub.310.3*L, 0.018*Lc.sub.320.3*L and 0.01*Lc.sub.330.3*L; each airfoil [PA.sub.ij] making part the external zone has an inclination angle .sub.ij (.sub.31, .sub.32 and .sub.33, respectively), wherein inclination angle .sub.ij at point (3) ranges between 41.sub.3160 and the inclination angle .sub.ij at the tip (b) ranges between 44.sub.3316.

14. The blade (e) according to claim 13, wherein chord length c undergoes a regressive change as it moves away from point (3), said chord length c having a value of 0.094*L, 0.080*L, and 0.070*L, for airfoils PA.sub.31, PA.sub.32 and PA.sub.33, respectively.

15. The blade (e) according to claim 13, wherein the inclination angle .sub.ij at point (3) ranges between 5.sub.3113 and the inclination angle .sub.ij at the tip (b) ranges between 5.sub.3315.

16. The blade (e) according to claim 2, wherein a tangent line at the tip (b) is at most, perpendicular to the rotation axis {right arrow over (Z)}.sub.0 when the blade shows its greatest curvature according to the combination of bending radius Rp.sub.1, Rp.sub.2 and Rp.sub.3 of the division sections En.sub.1, En.sub.2 and En.sub.3, wherein: Rp.sub.1 is the constant bending radius of the first division section En.sub.1 having a focus located on plane [P] at a distance bound by a range between 1.3*L.sub.1Rp.sub.157*L.sub.1; Rp.sub.2 is the constant bending radius of the second division section En.sub.2 having a focus located on plane [P] at a distance bound by a range between 1*L.sub.2Rp.sub.25*L.sub.2; Rp.sub.3 is the constant bending radius of the third division section En.sub.3 having a focus located on plane [P] at a distance bound by a range between 1*L.sub.3Rp.sub.312*L.sub.3.

17. The blade (e) according to claim 1, wherein said inclination angle .sub.ij ranges between 5.sub.ij25 at the root (a) and between 5.sub.ij15 at the tip (b).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a preferred embodiment of the blade and the direction wherein the fluid is moving in the present invention.

(2) FIG. 2 illustrates an overall three-dimensional view of the blade and its primary neutral axis included in plane P.

(3) FIG. 3 illustrates a detailed view of the first section with its respective bending radius.

(4) FIG. 4 illustrates a two-dimensional view of aerodynamic profile PA.sub.ij.

(5) FIG. 5 illustrates a two-dimensional view of the blade's first section along the {right arrow over (X)}.sub.0{right arrow over (Z)}.sub.0 plane.

(6) FIG. 6 illustrates a detailed three-dimensional view of the blade's cross-section.

(7) FIG. 7 illustrates a three-dimensional view of the blade's second section.

(8) FIG. 8 illustrates a three-dimensional of the blade's third section.

(9) FIG. 9 illustrates a three-dimensional view of the configuration in a preferred embodiment for the wind power generation system.

(10) FIG. 10 illustrates a view of the fluid flow through the wind power generation system.

(11) FIG. 11 illustrates the direction of rotation of the wind power generation system.

(12) FIG. 12 illustrates the blade's Cp (coefficient of power) for different speeds and different TSR.

BRIEF DESCRIPTION OF THE INVENTION

(13) The present invention discloses a blade for the generation of electrical energy stemming from the transformation of kinetic energy of a fluid, in rotational movement. Said rotational movement is moved to a central horizontal axis which may be coupled to an electric generator. Said horizontal axis is found defined by a Cartesian axis {right arrow over (Z)}.sub.0 which together with Cartesian axes {right arrow over (X)}.sub.0 {right arrow over (Y)}.sub.0, form a global orthogonal framework of clearance planes.

(14) Blade (e) has a particular geometrical shape which extends along axis {right arrow over (Z)}.sub.0, moving away thereof as it continues to develop, and is limited longitudinally by Base (a) and Tip (b), whose connection is obtained by a series of sectional and constant curvatures called Sectional Neutral Axes [En.sub.i] which generate all together a continuous or discontinuous primary curvature called Primary Neutral Axis [En]. Cross-sectionally, it is found limited by an Leading Edge (f) and an Trailing Edge (d), which when joined by one or two continuous curves which connect several points, amongst them the point corresponding to the leading edge and the trailing edge, form an Aerodynamic Profile PA.sub.ij having a variable or constant thickness. The volume defined by these five borders (Base, Tip, Leading Edge, Trailing Edge, Aerodynamic Profile) generates the shape of the blade.

(15) The main geometrical feature of the blade is the curvature, defined by the Sectional Neutral Axes [En.sub.i], which as mentioned above, when joined form the Primary Neutral Axis [En] whose curvature length is given by L, which may lie in the range of 0.01 mL30 m. In order to create this curvature, a series of points Pc.sub.ij are joined; these points are constructed along the bottom curve describing aerodynamic profile PA.sub.ij, at a distance of c/4 from the leading edge point, c being the length of the aerodynamic profile chord.

(16) Said Primary Neutral Axis [En] is included within plane P, which coincides with the {right arrow over (X)}.sub.0{right arrow over (Z)}.sub.0 plane. The initial point of Primary Neutral Axis [En], the base, is located by an auxiliary reference framework {right arrow over (X)}.sub.1{right arrow over (Y)}.sub.1{right arrow over (Z)}.sub.1; initiating at the intersection of plane {right arrow over (X)}.sub.1{right arrow over (Y)}.sub.1 which is parallel to plane {right arrow over (X)}.sub.0{right arrow over (Y)}.sub.0 and perpendicular to the rotation axis {right arrow over (Z)}.sub.0; with plane {right arrow over (Y)}.sub.1{right arrow over (Z)}.sub.1 which is parallel to plane {right arrow over (Y)}.sub.0{right arrow over (Z)}.sub.0; and to plane {right arrow over (X)}.sub.1{right arrow over (Z)}.sub.1 which coincides with plane {right arrow over (X)}.sub.0{right arrow over (Z)}.sub.0 and thus with plane P, if the preferred embodiment is had. This intersection point 1 between the auxiliary planes, is where Primary Neutral Axis [En] begins and is also identified as the initial point of the first of three division sections of [En].

(17) The first section of division L.sub.1 corresponds, in the blade's preferred embodiment, to 20% of L; however, it may range between 0.15*LL.sub.10.25*L. This section is limited by points 1 and 2, whereby the latter is found towards the end of the length of L.sub.1 over Sectional Neutral Axis [En.sub.1]. The second division section is defined by L.sub.2; this section begins at point 2 and ends at point 3 located over Sectional Neutral Axis [En.sub.2], in accordance to the preferred embodiment, this section has a length corresponding to 40% of L, but however it may vary between 0.3*LL.sub.20.5*L. The last division section of the blade corresponds to L.sub.3 and is limited by points 3 and 4; its length, as defined in the preferred embodiment is 40% of L, and like the other sections has a length between 0.3*LL.sub.30.5*L. The different arches defining each one of these sections, are tangents at each one of the connection points, i.e., section L.sub.1 is tangent to section L.sub.2 at point 2 and section L.sub.2 is tangent to section L.sub.3 at point 3.

(18) The shape of the blade undergoes a series of variations in its cross-section, which develop along the Primary Neutral Axis [En] from point 1 to point 4 and which like curvature L, these variations are analyzed at the same three sections L.sub.1L.sub.2L.sub.3. The first variation evidenced is the length of the cross-section, seen as the decrease or increase of the length of chord length c of aerodynamic profile PA.sub.ij. The length of said cross section is bound by ranges 0.05*Lc.sub.110.3*L and 0.01*Lc.sub.330.3*L, for aerodynamic profiles located at the base and tip of the blade, respectively.

(19) The second geometrical variation corresponds to an inclination which varies along Primary Neutral Axis [En] from point 1 to point 4 and which like curvature L, these variations are analyzed at the same three sections L.sub.1L.sub.2L.sub.3. This inclination is measured as a function of angle .sub.ij which is formed between chord length c of each PA.sub.ij profile and a perpendicular axis u to plane P which intersects Primary Neutral Axis [En] at point Pc.sub.ij. This angle may be both positive as well as negative, having angle 0 as an inflection point, which is formed when the a axis is parallel to the c chord. A positive angle exists when said angle grows clockwise and negative when counter-clockwise.

(20) At the base of the blade, the inclination angle may range between the following values, 38.sub.i148 and the tip's inclination angle may range between 46.sub.i40. However, in the preferred embodiment the inclination is found between 31.sub.i30 and 44.sub.i16 for the base and tip, respectively.

(21) For a configuration with greater performance, said inclination lies in the following ranges: 5.sub.i25 and 5.sub.i15, for the base and tip respectively.

DETAILED DESCRIPTION OF THE INVENTION

(22) The present invention discloses a blade for electric power generation stemming from the transformation of a fluid's kinetic energy into rotational movement, wherein the capacity of kinetic energy transformation into rotation movement is directly correlated to the effective contact area between the blade and air flow. The present invention provides an increase of said effective area in contrast to a conventional flat blade, given its curved shape allows that for an equal effective diameter, a greater contact surface can be provided and thus a greater amount of energy generated.

(23) In addition, the blade's curvature herein allows for the kinetic energy found in the fluid's flow to be used in a greater proportion in contrast to that obtained using a conventional mainly flat-shaped blade. The above due to that air flow impacting the blade does not do so perpendicularly as usually happens in conventional designs, wherein the greater part of the flow energy is transformed into drag forces associated to the pressure of impact, but instead, the flow impacting the blade does so at an angle with respect to the blade allowing for the flow to acquire velocity components which are used in kinetic energy transformation of the flow into rotational movement.

(24) The present invention discloses a blade for the generation of electrical power from the transformation of a fluid's kinetic energy into rotation movement. Said rotational movement is moved to a central horizontal axis which may be coupled to an electrical generator. This rotation horizontal axis is defined by a Cartesian axis {right arrow over (Z)}.sub.0 which together with Cartesian axes {right arrow over (X)}.sub.0 {right arrow over (Y)}.sub.0, form a global orthogonal framework of clearance planes.

(25) Making reference to FIG. 1 and FIG. 2, an embodiment of blade (e) of the present invention is shown, having a particular geometrical shape which extends along axis {right arrow over (Z)}.sub.0, moving away thereof as it continues to develop, and is limited longitudinally by Base (a) and Tip (b), whose connection is obtained by a series of sectional and constant curvatures called Sectional Neutral Axes [En.sub.i] which generate all together a continuous or discontinuous primary curvature called Primary Neutral Axis [En].

(26) Given the curvature of the Primary Neutral Axis [En] may be continuous or discontinuous, it is necessary, for the latter, divide its length in different sections which allows to characterize the invention in continuous curvatures or Sectional Neutral Axes [En.sub.i]. The number of sections is one (1) for continuous Primary Neutral Axes [En] and at least two (2) for discontinuous Primary Neutral Axes [En], wherein L.sub.2 comprises 50% of L and L.sub.3 the other 50%. However, for the preferred embodiment, the blade is divided into three (3) sections represented by Sectional Neutral Axes [En.sub.1], [En.sub.2], [En.sub.3] found between points 1-2; 2-3; and 3-4.

(27) The first division section En.sub.1 starts at point 1, has a preferred length of L.sub.1=0.2*L and ends at point 2. This section corresponds to the base zone, where the blade is attached to the horizontal rotation axis. En.sub.1 is a constant curve obtained from the polynomial interpolation of various points. Its constant bending radius Rp.sub.1 has a focus located at plane P at a preferred distance of Rp.sub.1=4*L.sub.1; said bending radius can range between 1.3*L.sub.1Rp.sub.157*L.sub.1. At point 1 and perpendicular to curve En.sub.1, plane A is located and having an angle {right arrow over (X)}{right arrow over (Y)}.sub.1 with plane {right arrow over (X)}.sub.1{right arrow over (Y)}.sub.1, said angle ranging between 0{right arrow over (X)}{right arrow over (Y)}.sub.190. However, its preferred value ranging from 0{right arrow over (X)}{right arrow over (Y)}.sub.140 and its greatest efficiency range between 10{right arrow over (X)}{right arrow over (Y)}.sub.120.

(28) In FIG. 2, section En.sub.1 is observed formed by at least three (3) cross-sections, whose geometrical shape is an aerodynamic profile PA.sub.ij, named PA.sub.11, PA.sub.12 and PA.sub.13. Each one of these profiles are found on a plane perpendicular to En.sub.1, the first plane A corresponds to profile PA.sub.11 and located at point 1; the second plane B belongs to profile PA.sub.12 and its location is at sectional neutral axis [En.sub.1] at an intermediate point between 1 and 2; at the third plane D, the aerodynamic profile PA.sub.13 is found and is located at point 2.

(29) Making reference to FIG. 3, which illustrates a detailed view of the first section showing the respective bending radius, it may be noted that on the bottom curve of aerodynamic profiles PA.sub.11, PA.sub.12 and PA.sub.13, called intratwo, points Pc.sub.11, Pc.sub.12 and Pc.sub.13 are located, respectively. These points are located at a distance of c/4 from the leading edge and by joining them in an arch containing them, the Sectional Neutral Axis [En.sub.1] is obtained.

(30) If a material extrusion is generated which follows the path described by the En.sub.1 curve and said path conserves the shape of multiple cross-sections in its sweep (aerodynamic profiles), the solid having the geometric shape of the invention is generated at the base zone.

(31) Using the configuration of greatest performance, this first section demonstrates a progressive change in its transverse length; this is due to the fact that chord length c suffers an increase in size as it moves away from the beginning of the En.sub.1 curve at point 1, where the chord shows values of 0.082*L, 0.092*L, 0.099*L, for profiles PA.sub.11, PA.sub.12 and PA.sub.13, respectively.

(32) However, this section may demonstrate progressive or regressive changes or a combination thereof in chord length, provided they are within the following ranges: 0.05*Lc.sub.110.3*L; 0.046*Lc.sub.120.3*L; 0.042*Lc.sub.130.3*L. Making reference to FIG. 4, a two-dimensional view of aerodynamic profiles PA.sub.ij is shown, wherein each aerodynmic profile PA.sub.ij making part of first division section En.sub.ij has an inclination angle .sub.ij (.sub.11.sub.12.sub.13) formed between chord length c of each PA.sub.ij profile and u axis. The first aerodynamic profile in this section may lie between the following values, 30.sub.11120 and the profile inclination angle and point 2 may lie between 34.sub.13105. However, in the preferred embodiment, said inclination is limited by the following ranges 5.sub.i25 and 1.sub.i19, for profiles .sub.11 and .sub.13, respectively (also see FIG. 6).

(33) In FIG. 7, it may be noted that second division section En.sub.2 initiates at point 2, has a preferred length of L.sub.2=0, 4*L and ends at point 3. This section corresponds to the internal zone, wherein the greatest percentage of aerodynamic forces that the blade generates in its entirety are concentrated. En.sub.2 is a constant curve obtained from the polynomial interpolation of several points. Its constant bending radius Rp.sub.2 has a focus located on plane P at a preferred distance of Rp.sub.2=2*L.sub.2; this bending radius may be in the following range: 1*L.sub.2Rp.sub.25*L.sub.2.

(34) Section En.sub.2 is made up of at least three (3) equidistant cross-sections, whose geometric shape is an aerodynamic profile PA.sub.ij, called PA.sub.21, PA.sub.22 and PA.sub.23. Each one of these profiles is found on a plane perpendicular to En.sub.2; the first plane E corresponds to profile PA.sub.21 and is located at point 2; the second plane F corresponds to profile PA.sub.22 and it is located on sectional neutral axis [En.sub.2] at an intermediate point between 2 and 3; aerodynamic profile PA.sub.23 is located on plane G and is located on point 3.

(35) On the bottom curve of aerodynamic profiles PA.sub.21, PA.sub.22 and PA.sub.23, called intratwo, points Pc.sub.21, Pc.sub.22 and Pc.sub.23 are located, respectively. These points are at a distance of c/4 from the leading edge and by joining them in an arch containing them, the Sectional Neutral Axis [En.sub.2] is obtained.

(36) If the material extrusion used in the first section (base) is continued, i.e. following the path described by curve En.sub.2 and maintaining the shape of the multiple cross-sections PA.sub.21, PA.sub.22 and PA.sub.23 in its sweep, the solid having the geometric shape of the invention is generated in the internal zone of the blade.

(37) This second section in contrast to the first shows two sectional changes in its configuration of greatest performance; the first being a progressive change in the length of chord length c from point 2 up to near the central point of curvature En.sub.2. This point, preferably located on plane F is considered the inflection point of the chord of the section's aerodynamic profiles, since from it, chord length c of the cross-sections describe a regressive behavior and its size begins to decrease until point 3. In accordance with this embodiment, the chord has a value of 0.099*L, 0.104*L, 0.094*L, for profiles PA.sub.21, PA.sub.22 and PA.sub.23, respectively.

(38) Nevertheless, this section may show progressive or regressive changes or combinations thereof in chord length, provided they are within the following ranges: 0.042*Lc.sub.210.3*L; 0.034*Lc.sub.220.3*L; 0.026*Lc.sub.230.3*L.

(39) Each aerodynamic profile PA.sub.ij making part of section En.sub.2 has an inclination angle .sub.ij (.sub.21.sub.22.sub.23) formed between chord length c and each PA.sub.ij profile and the u axis. The first aerodynamic profile of this section may lie within the following values, 34.sub.21105 and the final profile inclination angle at point 3 may range between 41.sub.2360. However, in its configuration of greatest performance, said inclination is bound by the ranges 1.sub.i19 and 5.sub.i13, for profiles .sub.21 and .sub.23, respectively.

(40) The third division section En.sub.3 initiates at point 3, has a preferred length of L.sub.3=0.4*L and ends at point 4. This section corresponds to the external zone, and here is where the greatest rotational velocity components are found, and therefore its inertia must be the least in order to reduce stresses; this is obtained by decreasing the size of the aerodynamic profiles which make part of the section. En.sub.3 is a constant curve obtained from the polynomial interpolation of various points. Its constant bending radius Rp.sub.3 has a focus located at plane P at a preferred distance of Rp.sub.3=5*L.sub.3; said bending radius can range between 1*L.sub.3Rp.sub.312*L.sub.3.

(41) Making reference to FIG. 8, section En.sub.3 is shown which is made up of at least three (3) equidistant cross-sections, whose geometric shape is an aerodynamic profile PA.sub.ij, called PA.sub.31, PA.sub.32 and PA.sub.33. Each one of these profiles is found on a plane perpendicular to En.sub.3; the first plane H corresponds to profile PA.sub.31 and is located at point 3; the second plane I corresponds to profile PA.sub.32 and is located on sectional neutral axis [En.sub.3] at an intermediate point between 3 and 4; aerodynamic profile PA.sub.33 is located on plane J and is located on point 4.

(42) On the bottom curve of aerodynamic profiles PA.sub.31, PA.sub.32 and PA.sub.33, called intratwo, points Pc.sub.31, Pc.sub.32 and Pc.sub.33 are located, respectively. These points are at a distance of c/4 from the leading edge and by joining them in an arch containing them, Sectional Neutral Axis [En.sub.3] is obtained.

(43) Continuing with material extrusion of the second section, i.e. following the path described by curve En.sub.3 and maintaining the shape of the multiple cross-sections (aerodynamic profiles) during its sweep, the solid having the geometric shape of the invention is generated in the external zone.

(44) This third and preferably last section, develops a regressive change in its transverse length for the embodiment of greatest performance; this is due to the fact that chord length c decreases its size as it moves away from the beginning of curve En.sub.3 at point 3. In accordance with this embodiment, the chord has a value of 0.094*L, 0.080*L, 0.070*L, for profiles PA.sub.31, PA.sub.32 and PA.sub.33, respectively.

(45) Nevertheless, this section may show progressive or regressive changes or combinations thereof in chord length, provided they are within the following ranges: 0.026*Lc.sub.310.3*L; 0.018*Lc.sub.320.3*L; 0.01*Lc.sub.330.3*L.

(46) Each aerodynamic profile PA.sub.ij making part of section En.sub.3 has an inclination angle .sub.ij (.sub.31.sub.32.sub.33) formed between chord length c of each PA.sub.ij profile and u axis. The first aerodynamic profile in this section may lie between the following values, 41.sub.ij60 and the profile inclination angle at point 4 may lie between 44.sub.3316. However, in its configuration of greatest performance, said inclination is limited by the following ranges 5.sub.i13 and 5.sub.i15, for profiles .sub.31 and .sub.33, respectively.

(47) The combination of bending radius ranges for sections Rp.sub.1, Rp.sub.2 and Rp.sub.3 must be in such a manner that when the blade has its greatest curvature, a tangent line at point 4 must be at most perpendicular to rotation axis {right arrow over (Z)}.sub.0.

Embodiment Example

(48) In order to carry out the blade fluid dynamics testing, several tests were run using computer simulation. The following is information evidencing the invention's performance: Operating conditions: sea-level Numerical method used: Finite volumes Simulator software used: Fluent (ANSYS).

(49) The blades were designed in order to operate optimally both at low as well as high speeds with an optimal rotor tip speed ratio (TSR) of 6; i.e., the rotor must rotate at an RPM such that the tangential speed of the blade tip is 6 times the velocity of the fluid it faces.

(50) FIG. 12 shows the blade's Cp (coefficient of power) for different speeds and different TSR. This demonstrated that efficiencies (Cp) over 40% for TSR between 4 and 7 are obtained. However, the greatest efficiency is gained for TSR between 5 and 6, the range in which the system is calculated will operate, as demonstrated in the FIG. 12. It is reminded that the maximum efficiency a rotor can achieve is 59.3%, which corresponds to the Betz limit which is 0.593.

(51) The performance demonstrated in FIG. 12 corresponds to one of the possible configurations whereby the invention may be constituted, mainly the preferred embodiment for a wind power generation system as shown by FIG. 9. This array comprises a total of three blades (e) radially placed at a 120 angle from each other, said blades (e) are fixed in the direction stated above by a support system (g); said support system (g) is attached to an electrical energy generating system having a rotation axis (h) (in the same location as imaginary rotation axis Z {right arrow over ( )}0) allowing for rotational movement of the blades (e) in the direction illustrated by the vectors (m); a shaft (j) located vertically which elevates the system up to a determined height, the electrical energy generating system is attached thereto which possesses a rotation axis (h) from which the support system (g) is attached which in turn holds the blades (e); a keel (i) attached to the shaft (j) which purpose is to cover the frontal zone of the system in order to smooth the fluid's flow (k) that impacts the blades (e); in this configuration of the preferred embodiment, said fluid (k) is air.

(52) Making reference to FIGS. 10 and 11, the present invention's operation is shown under the configuration set forth above, comprising the transformation of linear kinetic energy possessed by fluid (k) in movement, in rotational movement (m) of the blades (e) when these are impacted by air. The rotation process begins when the air impacts the leading edge (f) and moves through the bottom and top surfaces comprising the aerodynamic profiles PA.sub.ij of blade (e), until arriving finally to the trailing edge (d). The air passing through the top zone acquires greater speed than the air passing through the bottom zone, thus generating a pressure differential on these surfaces, which finally translates in a lift force having a component in the rotation direction (m) thus generating torque with respect to the rotation axis (h).

(53) The advantage offered by this invention with respect to prior art, is the capacity of transforming said kinetic energy in rotational movement which is directly correlated to the effective contact area between the blade (e) and the air flow (k); thus the invention presents an increase of said effective area in comparison to a conventional flat blade, this because of its curved shape which allows that for a same effective diameter, a greater contact surface can be made and therefore generating greater amount of energy.

(54) As stated above, the curvature of blade (e) allows for kinetic energy possessed by the flow (k) of the fluid in movement to be used in greater proportion than that obtained using a conventional flat-shaped blade. The above is true given the air flow impacting the blade is not perpendicular as usually happens in conventional designs, wherein the greater part of the flow's energy is transformed into drag forces associated to impact pressure, and in contrast, the flow impacts blade (e) at an angle with respect to the blade (e) allowing for the flow to acquire speed components which are used in transforming flow kinetic energy in rotational movement (m).

(55) It must be understood that the present invention is not found limited by the embodiments described and illustrated, since as shall be evident for those with skill in the art, variations and possible modifications exist that do not extend from the scope and spirit of the invention, which is only defined by the following claims.