WO2012001320A1

WO2012001320A1 - Vertical wind generator having winglets

Info

Publication number: WO2012001320A1
Application number: PCT/FR2011/051538
Authority: WO
Inventors: Daniel Yves Henri Emile Heulot
Original assignee: Okwind
Priority date: 2010-06-30
Filing date: 2011-06-30
Publication date: 2012-01-05
Also published as: FR2962172A1

Abstract

The invention relates to a device (1) for capturing the energy of a flow of fluid (F), comprising a rotor (2) the rotational axis (Z-Z') of which is intended to be arranged approximately transversely with respect to the direction of said flow of fluid, said rotor (2) being provided with at least one blade (3) enabling the flow of fluid (F) to rotate it, the device being characterized in that said blade (3) comprises at least one first, inclined transverse deflector(20), which is arranged such that the chord (C₂₀) of said first deflector (20), which connects the leading edge (20A) of said deflector (20) to its trailing edge (20F), forms, with the chord (C₃) of the blade (3) and in projection in the chord plane (Pc3) of said blade (3), a non-zero angle of attack (φ). Wind generators having a vertical axis.

Description

VERTICAL WIND TURBINE

TECHNICAL AREA

The present invention relates to the general field of devices for collecting the energy of a fluid stream which comprise a rotor driven by said fluid stream and whose axis of rotation is intended to be arranged transversely with respect to the direction incident fluid.

It relates especially to turbines called "vertical axis", such wind turbines or tidal.

The subject of the present invention is in particular a device for collecting the energy of a fluid stream comprising a rotor whose axis of rotation (Ζ-Ζ ') is intended to be arranged transversely with respect to the direction of said current of fluid, said rotor being provided with at least one blade allowing the flow of fluid to cause it to rotate.

PRIOR ART It is known to use rotating machines, such as turbines, in order to convert the energy of a moving fluid, such as water, air or steam, into mechanical and / or electrical energy.

In particular, vertical axis turbines of the Darrieus type are known, comprising a plurality of vertical blades, generally parallel to the axis of rotation, which are assembled to form a kind of drum and arranged so as to be propelled by the phenomenon of lift resulting from the flow of wind relative to their surface.

Although they offer undeniable advantages in terms of energy production, and more particularly of renewable energy exploitation, by means of a structure that can be relatively compact and that produces relatively little noise pollution, such wind turbines vertical axis suffer from some disadvantages. One of these drawbacks is that such wind turbines generally require relatively high speed wind speeds, or even mechanical assistance, to be able to start, which of course limits their range of use and imposes their implantation on sufficiently windy sites. . In addition, the efficiency of such wind turbines is generally moderate, or quite low at low wind speeds.

Such productivity limits of course constitute an obstacle to the generalization of the use of such wind turbines, in particular for making "small wind" installations, that is to say, whose dimensions and power are adapted to a particular wind turbine. implantation on commercial or residential buildings, particularly in an urban or peri-urban environment.

STATEMENT OF THE INVENTION

The objects assigned to the present invention therefore aim at remedying these drawbacks and at proposing a new device for collecting the energy of a fluid stream that can be effectively rotated by a fluid stream, in particular a gaseous stream, of low speed.

Another object assigned to the invention is to propose a new device for capturing the energy of a fluid stream whose structure is particularly simple, compact, and inexpensive to manufacture. Another object assigned to the invention is to propose a new device for collecting energy from a particularly robust and versatile fluid stream, which has a wide range of operation.

Another object assigned to the invention is to propose a new device for capturing the energy of a fluid stream whose efficiency is optimized. Another object assigned to the invention is to propose a new device for capturing the energy of a fluid stream whose operation generates little, if any, nuisance, especially visual or sound. Finally, another object assigned to the invention is to propose a new type of wind turbine for "small wind", particularly suitable for low-power energy production and installation on public buildings, commercial premises or the homes of individuals. The objects assigned to the invention are achieved by means of a device for collecting the energy of a fluid stream, comprising a rotor whose axis of rotation (Ζ-Ζ ') is intended to be arranged substantially transversely to the direction of said fluid stream, said rotor being provided with at least one blade allowing the flow of fluid to drive it to rotate, said device being characterized in that said blade comprises at least a first transverse deflector inclined which is arranged so that the rope of said first deflector, which connects the leading edge of said deflector to its trailing edge, forms, with the rope of the blade and in projection in the cord plane of said blade, a non-zero angle of attack.

SUMMARY DESCRIPTION OF THE DRAWINGS Other objects, characteristics and advantages of the invention will appear in more detail on reading the description which follows, as well as with the aid of the appended figures, provided for purely illustrative and non-limiting purposes, among which:

- Figure 1 A is a perspective view of a device according to the invention.

FIGS. 1B and 1C show the device of FIG. 1A, in a top projection view and a side projection view.

- Figure 2A illustrates, in a perspective view, an embodiment of blade provided with inclined transverse deflectors, as implemented within the device of Figures 1A to 1C.

- Figures 2B, 2C and 2D illustrate the blade shown in Figure 2A in side views (intrados), front (leading edge), and from above.

FIGS. 3A, 3B, 3C and 3D represent, in perspective views, a sagittal section, a top projection and a frontal section, a deflector variant; according to the invention, as implemented in particular on the pay and the device of the preceding figures.

- Figures 4A, 4B and 4C, respectively 5A, 5B and 5C are, in perspective views, in sagittal section and from above respectively, a second and a third embodiment of deflectors according to the invention.

- Figure 6 illustrates, in a side view, an alternative embodiment of the device according to the invention differs in particular from that illustrated in Figure 1 B by the implementation of a fourth embodiment of deflector.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention generally relates to a device 1 for capturing the energy of a fluid stream F.

For this purpose, the device 1 comprises a rotor 2 provided with at least one blade 3 allowing the fluid stream F to drive it to rotate about an axis of rotation (Ζ-Ζ ').

According to the invention, the axis of rotation (Ζ-Ζ ') of the rotor 2 is intended to be disposed substantially transversely with respect to the direction of the fluid flow F, that is to say designed to be disposed of so that said fluid stream F approaches the device 1 laterally, in a direction which is not collinear with the axis of rotation (Ζ-Ζ '), and which is on the contrary, particularly preferably, substantially perpendicular to said axis of rotation. More particularly, the device 1 can thus constitute a wind turbine or a vertical axis turbine, and particularly preferably a Darrieus type wind turbine, propelled essentially by lift phenomenon resulting from the circulation of fluid on both sides of the blade. 3, and more particularly "relative incident wind" V | _R resulting from the combination (vector) of the incident wind F on the one hand and the relative wind ν _ω related to the rotational movement of the blade.

In what follows, for convenience of description, the device 1 will be likened to a vertical axis wind turbine. Of course, said device 1 can be adapted to fluids of different natures, such as air (wind), liquid water (stream, marine currents) or any gas such as steam. water.

Furthermore, the fluid stream F can indifferently be natural or artificially generated by any means.

Overall, the device 1 is therefore in the form of a rotating machine, of the turbine type, the rotor 2 of which is capable of converting the kinetic energy of the fluid stream F into a rotational speed movement ω around the rotor. rotation axis (ZZ).

Advantageously, the rotor 2 can be rotatably mounted and guided on a stator 4, which can advantageously comprise a base 5 provided with fixing means intended to secure the device 1 to any implantation site, forming a reference system, such as the ground, a building, a roof, a mast, a vehicle, etc.

Preferably, the device 1 comprises a plurality of blades 3, preferably identical to each other and regularly distributed around the axis of rotation (ZZ), the rotor 2 thus having substantially a structural invariance by rotation of order n, n being the number of blades 3.

Each blade has a leading edge 3A at which it slices the air when it is rotating, as well as a trailing edge 3F. The leading edges 3A and 3F of leakage are connected to each other by side faces, preferably solid, profiled and substantially smooth, forming a 3I intrados and an extrados 3E.

The term "rope" C3 of the blade 3 is the right segment which joins the leading edge 3A to the trailing edge 3F, and the term "rope surface", or "rope plane", the average generating surface of the blade 3 which corresponds to the succession of blade ropes C3. Of course, the profile of the blade 3 may be subject to variations without departing from the scope of the invention. However, according to a particularly simple preferred embodiment, the intrados 31 and the extrados 3E of the blade 3 will be substantially convex and symmetrical with respect to the chord plane P _C 3.

According to alternative embodiments not shown, it is possible that the blade or blades 3 have a curved Pc3 rope surface, said blades having for example an outer bulge in their central portion while their lower ends 6 and upper 7 are closer to the axis of rotation (Ζ-Ζ ') as said central portion.

Similarly, said rope surfaces P _C blades 3 may be more or less twisted.

However, according to a particularly simple embodiment and inexpensive to manufacture, the blades 3 extend substantially rectilinear and parallel to the axis of rotation (Ζ-Ζ '), according to a plane of rectilinear rope in its two dimensions extension, as is illustrated for example in Figures 1A, 1C, 2A or 6. Preferably, their intrados 31 is oriented substantially towards said axis, while their upper face 3E is oriented to the opposite, to outside, and points towards the region of the space located (radially) beyond the scanning path 8 traversed by said blades 3.

In a particularly preferred manner, the chord plane Pc3 of each of the blades 3 will be substantially tangent to said scanning path 8, which preferably corresponds, as illustrated in FIG. 1B, to a substantially circular trajectory.

Of course, it is not excluded to opt for another azimuth adjustment of the blades 3, the chord plane P _C 3 thereof being able to form, in projection in a base plane π substantially normal to the axis of rotation (Ζ-Ζ '), a non-zero angle with respect to the tangent to the scanning path 8. Advantageously, however, the orientation of the blades 3 with respect to the axis, the rotor and the scanning path will be such that, when the rotor is moving, the leading edge 3A is substantially upstream, so as to be able to split the air and allow the relative wind to be distributed on both sides of the chord plane P _C 3 and flowing from said leading edge 3A to the trailing edge 3F simultaneously on the upper surface 3E and the lower surface 31.

Furthermore, the blades will preferably be elongated, that is to say preferably have a height, measured along the axis of rotation (Ζ-Ζ '), greater than their other dimensions. They will also preferably be substantially flattened to facilitate the flow of the fluid around them, and may for this purpose have a width, measured between their leading edge 3A and their trailing edge 3B, and more particularly a length of I_c3 rope, greater or more than several times, at their maximum thickness E3, measured laterally between their extrados 3E and their intrados 31.

Preferably, as illustrated in particular in FIGS. 1A to 1C, the blades 3 may advantageously be connected to the hub 10 of the rotor 2 by means of one, and preferably of, several rigid arms 11.

Said arms 11 will maintain the rigid and substantially invariant in a fixed position, each blade relative to the hub 10 and relative to the other blades.

For this purpose, each blade will preferably be provided, on its intrados 3I, for example substantially at the first third and second third of its height h, fixing means 12 comprising for example a flat or an impression 13 in or on which the external radial edge of the arm 11 can be fitted and fixed, for example by screwing, preferably substantially perpendicular to the plane of rope Pc3 of the blade.

Preferably, the arms 1 will be in the form of substantially rectilinear plates and normal rotation axis (Ζ-Ζ ').

Of course, the leading and trailing edges of said arms may be profiled to improve the overall efficiency of the device 1.

According to an important characteristic of the invention, as illustrated in particular in FIGS. 1A, 1C, 2B and 6, the blade or blades 3 comprise at least a first inclined transverse deflector, which is arranged such that the rope C ₂ o of said first deflector 20, which connects the leading edge 20A of said first deflector 20 to its trailing edge 20B, forms, with the rope C ₃ of the blade 3, and in projection in the cord plane P _C 3 of said pay 3, a non-zero angle of attack φ. Thus, the deflector 20 has an angle of attack, or "angle of incidence", or "pitch angle" φ non-zero.

Preferably, said deflector is thus inclined, in the direction of circulation of the fluid around the blade 3, so that its rope C20 and more generally its mean P _C 2o chord plane, extend generally between the edge 20A attack of said deflector and its trailing edge 20F, non-normal way, that is to say non-perpendicular to the edge of the leading edge 3A of the blade 3, and / or non-normal to the edge of the trailing edge 3F of said blade 3.

In particular, when the transverse section S3 of the blades 3, perpendicular to their chord plane Pc3, and containing the chord C3 which joins the leading edge 3A to the trailing edge 3F in the shortest distance, is also substantially normal to the axis of rotation (Ζ-Ζ '), that is to say substantially contained in a horizontal plane in FIGS. 1A, 1C and 6, or else, independently of the configuration of the blades themselves, this inclination of the deflector 20 may advantageously result in a protruding bevel arrangement of the chord plane Pc2o of said deflector 20 relative to a base plane normal to the axis of rotation (Ζ-Ζ '), substantially to the right of the blade 3 and along the rope thereof, and more particularly at the tangent of the tangent to the scan path 8.

The invention thus also relates as such to a device 1 comprising at least one blade 3 provided with at least one inclined first deflector 20, including the rope 20, which joins the leading edge 20A of said deflector 20 to its edge. 20F leakage by the shortest path, and preferably whose chord plane 20 as a whole, present (nt) globally, in projection in the cord plane Pc3 of the blade 3, and with respect to a normal basic plane to the axis of rotation (Ζ-Ζ '), such as for example the plane normal to the axis of rotation which contains the point of junction between the leading edge 3A of said blade and the deflector 20, an angle d φ non-zero attack. In addition, the blade 3 preferably comprises a second inclined transverse deflector 21, remote from the first deflector 20, and oriented in a convergent manner with the latter, as illustrated in particular in FIGS. 1A, 1C, 2A, 2B and 6 .

In other words, the respective chord planes Pc2o, Pc ₂ i of the first and second deflectors 20, 21 are not parallel, but instead intersecting, so as to delimit between them a section of blades forming a kind of guide or convergent duct, non-zero angular aperture.

Of course, the characteristics of the second deflector can be deduced from those of the first deflector mutatis mutandis. Preferably, the first and / or the second deflector 20, 21 is folded so as to converge, since its trailing edge 20F which points towards the end 6 of the blade 3 which is closest to it, to its edge 20A which is closer to the opposite end 7 of the same blade 3. In other words, the angle of attack φ preferably forms a positive penetration angle conferring the deflector a character " diving "in the direction of movement of the blade.

More particularly, the first and the second deflectors can thus converge towards one another from the trailing edge 3F towards the leading edge 3A of the blade 3, that is to say be arranged one towards the other so as to form a narrowing of the bearing surface of the blade, the leading edge of the blade section between said baffles 20, 21 being shorter than the trailing edge of this blade. same section of blade 3.

Particularly advantageously, the inclination, and more particularly the convergence of the first and second deflectors 20, 21 makes it possible to increase the projected surface of the blade 3 in a plane substantially normal to its rope C3, that is to say say to offer a better wind catch when the incident fluid stream reaches said blade 3 by its trailing edge 3F.

In other words, the arrangement according to the invention makes it possible to significantly reduce the speed of fluid current required for starting the device 1, conferring to the blades 3 an additional thrust surface at the intrados 20I, 211 of the first and second deflectors.

Thus, at startup, when the rotational speed ω of the rotor 2 is small, or even substantially zero, that is to say that the lift effect is small, the rotor 2 can advantageously be propelled, at least in part, by the kinetic pressure of the fluid stream on the additional thrust surfaces thus created by the baffles.

In this respect, it is remarkable that the useful projected area of these additional thrust surfaces is substantially equal to the product of the apparent surface of the intrados 20I, 211 of the deflectors 20, 21, multiplied by the sinus of the angle of attack φ .

Once the rotor 2 has a sufficient rotational speed, the lift phenomenon becomes preponderant and allows it to accelerate significantly, until reaching speeds of the order of 120 rpm, 400 rpm on the model tested which included three blades arranged at 120 degrees, for a span (overall diameter) of about 2 m and an overall height H of about 1.5 m, which resulted in an electric generator of 1000 W (nominal power).

The device 1 according to the invention is therefore advantageously capable of starting autonomously, for relatively low incident fluid current speeds, and in particular for wind speeds of the order of 7 m / s on the model of wind turbine tested, while the same model devoid of deflectors according to the invention so far started only under a wind of 9 m / s (see Table 1 below).

Preferably, the first deflector 20 is fixed substantially to an end 6 of the blade 3, which corresponds to the lower end, the closest to the reference frame, in FIGS. 1A, 1C and 6.

Similarly, the second deflector 21 may be fixed substantially to the other end of the blade 3, here the opposite upper end 7. In a particularly advantageous manner, the first and / or the second deflector 20, 21 can thus be arranged in the manner of wings, or "winglets", located on either side of the pay 3, at the level of the songs of this last, so border and laterally delineate the intrados 3I and the extrados 3E. Surprisingly, it has indeed been found that such an arrangement allows the deflector not only to improve the performance of the device 1 in terms of starting, but also to improve the efficiency of said device once the rotor 2 has been driven. rotation.

Thus, it would seem that not only the presence of inclined deflectors 20, 21 in accordance with the invention does not generate additional disturbing drag that could degrade the efficiency, compared with the possible use of "flat" deflectors, it is ie horizontal, but on the contrary contributes to improving the absolute performance of the device 1, that is to say the power captured and restored for a given incident wind speed. Thus, as shown in the figures, the deflector (s) 20, 21 will preferably form terminal fins that cap substantially transversely edges of the blades 3, preferably such that the rotor 2 has a arrangement substantially symmetrical with respect to its median plane, normal to the axis of rotation (Ζ-Ζ ') and cutting the blades 3 at mid-height. Preferably, the deflectors 20 are directly contiguous to the end of the blade 3, and advantageously carried exclusively by the latter, at a distance from the hub 10 and the arms 11, which gives such lightweight, robustness and simplicity to the rotor structure 2.

Preferably, the angle of attack φ is substantially between 2 degrees and 20 degrees, preferably between 5 degrees and 15 degrees, particularly preferably between 7 degrees and 12 degrees, or even substantially equal to 8 degrees, 9 degrees or 10 degrees. Of course, this inclination is likely to be optimized by means of test campaigns, depending in particular on the nature of the fluid stream and the dimensions of the device 1.

By way of example, the inventors have found that the use of a non-zero angle of attack at the level of the baffles also makes it possible to improve the power efficiency of the device 1, and more particularly of a wind turbine of the type Darrieus, of the order of 15% for an angle of attack φ of the order of 10 degrees.

Preferably, as shown in the figures, the first and / or the second deflector 20, 21 overflow both the upper surface 3E and the lower surface 31 of the blade 3. In other words, each deflector 20, 21 preferably projects in two opposite directions, on either side of the chord plane Pc3 of the blade 3.

Similarly, the first and / or the second deflector 20, 21 preferably project upstream of the leading edge 3A of the blade and / or downstream of the trailing edge 3F of said blade 3. Preferably, the first and / or the second deflector 20, 21 may protrude in the manner of a wide-brimmed hat substantially in all directions transverse to the average generative line of the blade 3, and overhang the surfaces of said blade in all directions.

Advantageously, the deflectors 20, 21 may thus form a kind of profiled collar at the end of the blades 3, the lateral and / or frontal strips visible from the intrados 20I, 211 of each deflector 20, 21, which are located on the side and else of the blade 3, thus creating, as previously mentioned, additional thrust surfaces facilitating the automatic start of the rotor 2.

In addition, the first and / or the second deflector 20, 21 are preferably substantially centered on the rope C3 of the blade 3.

In other words, the lateral portions of the deflector 20 preferably protrude substantially on an equal distance with respect to the intrados and the extrados of the blade respectively, and / or the frontal or caudal portions of said deflector 20 preferably project substantially at an equal distance from the leading edge 3A and the trailing edge 3F of said blade 3.

Furthermore, the first and / or the second deflector 20, 21 preferably have, laterally, in their chord plane P _C2 0, Pc ₂ i _> a substantially symmetrical profile, as illustrated in FIGS. 3C, 4C, and 5C.

In a particularly preferred manner, the deflector 20, 21 may have a substantially symmetrical structure, whose sagittal plane P _s , substantially perpendicular to the chord plane Pc2o, Pc ₂ i of said deflector, substantially coincides with the chord plane P _C3 of the blade 3, said sagittal plane thus preferably being substantially vertical and tangential to the scanning path 8, as illustrated in particular in FIGS. 1B or 2A.

More generally, it is remarkable that each blade 3 as a whole, including the deflectors 20, 21, may be symmetrical with respect to the chord plane P _C 3.

Furthermore, the first and / or the second baffle preferably laterally, in their chord plane Pc ₂₀ , Pc ₂ i _> a profile which is widened in its upstream portion, that is to say in the vicinity of the edge d 20A attack, 21 A, and tapering towards the trailing edge 20F, 21 F as shown in particular in Figures 1A, 1B, 2B, 3C, 4C or 5C.

The baffles will preferably have a rope length L _C 2o substantially greater than their width l ₂ _>> itself substantially greater, or even several times greater than their maximum thickness E _MAX -

Preferably, the lower surface 20I of the first deflector 20 and / or the lower surface 211 of the second deflector 21 is substantially plane. Such an arrangement allows in particular to simplify the manufacture or the introduction of the baffles 20, 21 of the blades 3, their respective intrados thus being substantially coincident with their rope plans Pc2o and P _C 21 respective.

Of course, it is not excluded to confer on the contrary to the intrados of said deflectors, which face each other on either side of the blade 3, a curved profile and in particular curved, or even having a succession of concave sections then convex, a possible bulging of the intrados 20I, 211 is however preferably less marked, with respect to the rope C20, C21, than that of the extrados 20E, 21 E.

Furthermore, according to an alternative embodiment illustrated in FIG. 6, it is conceivable for the first and / or second deflector 20, 21 to be formed by a plate whose intrados 201 and extrados 20E are both substantially planar, and preferably parallel such that said baffle has a constant thickness.

Of course, such an alternative embodiment greatly simplifies the manufacture of the baffles and therefore substantially reduces their cost. Nevertheless, it has been observed by the inventors that it is generally preferable, from an aerodynamic point of view, for the extrados 20E of the first deflector 20 and / or the extrados 21 E of the second deflector 21 to be bulged so as to present a bulge 22 towards its leading edge.

Thus, in other words, the deflector 20, 21 preferably has a substantially rounded bead at its leading edge, then generally tapers towards its trailing edge 20F, 21F, according to a profile of preferably continuously curved.

Of course, many extrados profiles 20E, 21E are conceivable without departing from the scope of the invention, said profiles being more or less pronounced, and may include in particular one or more convex corrugations, and one or more concave portions as shown in FIGS. 3B, 4B and 5B, Advantageously, (e) the extrados 20E, 21E of the deflector (s) 20, 21 may have a generally round bow shape, rounded and curved at the same time, in the sagittal plane P _s , between the leading edge 20A, 21A and the trailing edge 20F, 2F, as illustrated for example on the sagittal sections of FIGS. 3B, 4B and 5B, and transversely, from the radially inner edge of the deflector towards the radially outer edge thereof , as is particularly visible in Figures C, 3A, 4A, 5A, or again in Figure 3C which shows the cut section of the deflector 20 in a frontal plane P _F (or "coronai plane") which is in species carried by a radial direction vis-à-vis the axis of rotation (Ζ-Ζ '), and perpendicular to the chord plane of said deflector (and therefore tilted here relative to the vertical direction of the axis of rotation of a value equal to that of the angle of attack).

Advantageously, the crown of the extrados 20E, 21 E, and more particularly its double curvature bow, gives the deflector 20, 21, side or "leans" the latter, good aerodynamic properties. Indeed, such a shape minimizes its resistance to penetration and advancement, because it limits the coefficient of drag of the deflector 20, 21 vis-à-vis the relative wind ν _ω flowing from the edge of 20A attack towards the trailing edge 20B of said deflector when the rotor 2 rotates.

In this respect, it is remarkable that, more generally, the deflector (s) 20, 21 will preferably be arranged, shaped and oriented so that they have a drag coefficient (Cx) "in the bow", which applies in the direction of relative wind flow ν _ω (or relative incident wind V | _R ) when it meets the extrados 20E and flows from the leading edge 20A to the trailing edge 20F, which is less than the coefficient trailing "in stern", which applies in the direction of flow of the incident wind F when it meets the underside 20I and flows in the opposite direction, the trailing edge 20F to the leading edge 20A.

Thus, for low rotational speeds, and in particular during start-up, the engine torque associated with the driving thrust effect resulting from the drag generated by the incident wind F blowing "on the stern" on the lower surface, is favored. that the resisting torque resulting from the drag generated by the relative wind, of the moderate rest, which flows from the "bow" towards the "stern" is minimized. Such an arrangement of the deflectors, which have a low Cx in the direction of travel and a higher Cx in the opposite direction, improves the efficiency of the wind turbine at startup, which can occur by particularly low wind F, without to disturb or significantly reduce the steady state performance, when the relative wind becomes predominant.

As such, although the shape and extent of the extrados 20E, 21 E crown may be subject to variations, it has been observed that it may be preferable not to exaggerate the height of the latter. , a machine equipped with deflectors having a sharply defined "shark fin" profile, such as that represented in FIGS. 4A and 4B, tending to be, at constant parameters, moreover, less efficient, in steady state, than Eoiienne equipped with less bouncing profiles, such as those shown in Figures 3A, 3B or 5A, 5B.

According to an alternative embodiment, corresponding in particular to FIGS. 1A, 1C, 3A and 3C, the transverse section of the deflector 20, 21 may have a profile reminiscent of a flattened drop of water, and whose maximum thickness Emax is such that, given the value of the angle of attack φ, the deflector 20, 21, and more particularly its extrados 20E, 21 E is entirely contained inside the rotor 2, that is to say located in the side of the blade 3 and the rotor 2 relative to a base plane π substantially normal to the axis of rotation (Ζ-Ζ ') and tangent to the trailing edge 20F, 21 F of said deflector, as shown on Figure 1C.

In other words, the leading edge 20A of each deflector moves substantially in the wake of the deflector in front of it, the attack of the deflector "follower" being somehow "safe" from the trailing edge the deflector which precedes it, and thus tends to "open the road". Advantageously, such an arrangement is capable of conferring on the blades 3 an excellent ability to penetrate into the fluid and to limit their drag, especially when the rotor reaches high speeds.

Furthermore, the roll angle Θ of the first deflector 20 and / or the second deflector, considered around the rope C20, C21 of said deflector 20, 21 which is located in the Pc3 chord plane of the blade 3, is substantially between -5 degrees and +5 degrees and is preferably substantially zero.

In other words, if the deflectors 20, 21 have a plate whose angle of attack φ (that is to say, pitching) is not zero, they are instead arranged preferably so as not to they are tilted in a centrifugal direction towards the outside of the rotor or on the contrary inclined in a centripetal direction towards the axis and the center of the rotor from the blade 3.

As such, within a H-type Darrieus wind turbine such as that shown in FIGS. 1A, 1C or 6, the chord planes of the deflectors are preferably generated on the one hand by a C20, C21 chord deflector which is not only located in the plane of rope P _C 3 of the blade 3 but also inclined (here relative to the horizontal) an angle of attack φ, and secondly by a line substantially normal to the axis of rotation, that is to say substantially radial and in this case parallel to the horizontal plane. Thus, each deflector preferably extends in majority or even entirely outside the volume containing the rotor and delimited by the two normal planes to rotation axis and each passing through an end 6, 7 of the blade, at the junction the leading edge 3A of said blade 3 with said deflector.

As an indication, tests were carried out on a three-bladed wind turbine of the type represented in FIG. 1 A and which had the following characteristics:

- Average height of blade h = 1, 37 m

- Overall height: H = 1,483 m

- Diameter swept by the chord plane of the blades (scanning path diameter 8): D = 2,030 m

- Length of blade rope: L _C 3 = 0.35 m

- Thickness of blade: E ₃ = 47 mm

- Deflector width (of the type of FIGS. 3A-3C): 120 = 222 mm

- Baffle cord length: L _C 2o = 576 mm - Thickness of deflector: Emax = 46 mm

- Load: generator of 1000 W (nominal power), 800 W maximum, direct drive, without reducer or multiplier.

The results obtained during the tests were recorded in Table 1 below:

Table 1

In addition to the influence of the deflectors, and more particularly of their inclination, on the starting capacities of the wind turbine, it has been found that, in steady state, in this case for an incident wind speed of 9.3 m / s, the use of "flat water droplet" deflectors according to FIGS. 3A, 3B, 3C, 3D provided a power improvement of the order of 7% compared with the use of planar baffles (FIG. 6). whereas, on the other hand, the use of "shark fin" deflectors Figures 4A, 4B and 4C could cause a power degradation of up to 7.4% compared to that achieved with said flat deflectors.

The operation of a preferred embodiment of the invention will now be described with reference to FIGS. 1A, 1 B, 1C, for a vertical axis wind turbine of the Darrieus type.

Initially, the speed of the incident fluid is zero and the rotor 2 is stationary, or even blocked by any brake.

When the wind rises, an incident fluid stream impinges on the rotor 2 and circulates particularly along the blades 3. In doing so, the incident fluid, which approaches the wind turbine in a south-north direction, flows in particular from the 3F trailing edge to the leading edge 3A of the blade 3 which is located in the "west" and in particular in the quadrant "southwest" in Figure B.

Simultaneously the fluid stream is captured by the deflectors 20, 21 and deflected by them to the median plane of the rotor 2.

The fluid stream thus exerts on the projecting portions of the intrados 20I, 211 of said deflectors 20, 21, on a surface substantially equivalent to their projection in an incidence plane substantially normal to the direction of the incident fluid, a substantially orthoradial thrust component. which generates a torque contributing, or even sufficient, to the start of the rotor.

When the rotor 2 comes into motion, i.e. initiates its rotation ω about the axis (Ζ-Ζ '), the blades split the air so that a relative wind V _w , and by consequently, an incident relative wind V] _R appears and progressively increases.

Said incident relative wind flows from the leading edge 3A towards the trailing edge 3F of the blades 3, while flowing simultaneously on the lower surface 31 and the upper surface 3E, and in particular partly along the zones bordered for the one through the lower surface 31 of the blade and the first portion (radially internal) of the lower surface 201 of the deflector 20, and for the other by the upper surface 3E of the blade and the second portion (radially outer) of the lower surface 201 of the deflector. These flows create a lift force P which is exerted especially on the blade located in the wind, that is to say in the south in Figure 1B, and on the blade located downwind, that is to say say north in Figure 1 B, These lift forces gradually accelerate the rotor 2, until the latter reaches its maximum speed, especially given the load.

Particularly advantageously, it has been observed that the device according to the invention makes it possible not only to obtain a low speed start of incident wind, but also to improve the power output at constant wind speed, and particularly to low wind speed, especially when the rotor is launched in steady state.

In addition, the device 1 thus obtained has a good power density, insofar as it has a relatively light structure, discrete and compact. As such, it is remarkable that the blades 3, the arms 11 and the deflectors, in particular, can be made of composite material.

In addition, the device 1 generates almost no noise, its operation is particularly quiet.

Therefore, said device is particularly well suited for use in "small éoiien" in the vicinity of commercial or residential premises. Of course, the implementation of the invention is however not limited to such a scale of realization and could perfectly be envisaged for large devices intended for a truly industrial production of energy, including electrical energy , for example within wind farms.

POSSIBILITY OF INDUSTRIAL APPLICATION The present invention finds particular application in the design of wind turbines and the exploitation of wind energy.

Claims

- Device (1) for collecting the energy of a fluid stream (F) comprising a rotor (2) whose axis of rotation (Ζ-Ζ ') is intended to be disposed substantially transversely to the direction said fluid stream, said rotor (2) being provided with at least one payload (3) enabling the fluid stream (F) to drive it to rotate, the device being characterized in that said blade (3) comprises at least one minus a first inclined transverse deflector (20), which is arranged such that the rope (C20) of said first deflector (20), which connects the leading edge (20A) of said deflector (20) to its trailing edge ( 20F) forms with the rope (C ₃ ) of the blade (3) and in projection in the chord plane (P _C 3) of said blade (3), a non-zero angle of attack (φ). - Device according to claim 1 characterized in that the blade (3) comprises a second deflector (21) transverse inclined, remote from the first deflector (20) and oriented convergently with the latter. - Device according to claim 2 characterized in that the first and the second deflector (20, 21) converge from the trailing edge (3F) towards the leading edge (3A) of the blade (3). - Device according to one of the preceding claims characterized in that the first and / or the second baffle (20, 21) are each fixed substantially at one end (6, 7) of the blade (3). - Device according to one of the preceding claims characterized in that the angle of attack (<p) is substantially between 2 degrees and 20 degrees, preferably between 5 degrees and 5 degrees, and particularly preferably between 7 degrees and 12 degrees, even substantially equal to 8 degrees, 9 degrees or 10 degrees. - Device according to one of the preceding claims characterized in that the first and / or the second deflector (20, 21) overflows both the extrados (3E) and the intrados (31) of the blade (3 ). - Device according to one of the preceding claims characterized in that the first and / or the second deflector (20, 21) protrudes upstream of the leading edge (3A) of the blade and / or downstream of the trailing edge (3F) of said blade (3). - Device according to one of the preceding claims characterized in that the first and / or the second deflector (20, 21) is substantially centered on the rope (C ₃ ) of the blade (3). - Device according to one of the preceding claims characterized in that the first and / or the second baffle (20, 21) has laterally, in its chord plane (Pc2 ₀ , Pc2i), a substantially symmetrical profile. - Device according to one of the preceding claims characterized in that the first and / or the second deflector (20, 21) has laterally, in its chord plane (Pc ₂ o, Pc ₂ i), a profile which is expanded in its upstream portion and tapers towards the trailing edge (20F, 21F). - Device according to one of the preceding claims characterized in that the intrados (20I) of the first deflector and / or (211) of the second deflector is substantially planar. - Device according to one of the preceding claims characterized in that the extrados (20E) of the first deflector and / or that (21 E) of the second deflector is curved so as to have a bulge towards its leading edge (20A, 21 A). - Device according to one of the preceding claims characterized in that the roll angle (Θ) of the first and / or the second deflector (20, 21) around its rope (C20, C21) located in the chord plane ( P _C 3) of the blade is substantially between -5 degrees and +5 degrees, and preferably substantially zero. - Device according to one of the preceding claims characterized in that it constitutes a wind turbine vertical axis Darrieus type.