FR3105995A1 - TRANSVERSE FLOW TURBINE - Google Patents

Abstract

The invention relates to a transverse flow turbine system (10), comprising a shaft (1), a plurality of arms (2, 2 ', 2' ') mounted on the shaft, a plurality of blades (6, 6 ', 6' '), each blade being mounted on a respective arm, and being free to rotate, and for each blade, a stop device (21, 21', 21 ''), defining a first stop position and a second stop position limiting the rotational movements of said blade between said first and second stop positions, so that the corresponding blade is free to rotate over an angular range (P) of at least 70 °, this value being included, and at most 100 °, this value being excluded, in which the angle (I) between the first stop position and the tangential direction (T, T ', T' ') is between 35 ° and 55 °, in absolute value, and the angle (E) between the second stop position and the tangential direction is between 35 ° and 55 ° in absolute value Figure for the abstract: figure e 1

Description

CROSS FLOW TURBINE

The invention relates to cross-flow turbines, for example to wind turbines with a vertical axis of rotation or even to transverse-flow tidal turbines.

The most common wind turbines have a horizontal axis, parallel to the direction of the wind, conventionally comprising a mast, a nacelle housing a rotating shaft and blades.

We also know wind turbines with a vertical axis, that is to say having an axis assumed to be perpendicular to the direction of the wind. In other words, the axis can extend along its longitudinal direction vertically in the classic sense of the term (following the gravity vector), but also along other directions, in particular horizontal, provided that they are perpendicular to the expected direction of the wind. .

Among vertical axis wind turbines, mention may be made of wind turbines of the Darrieus type, wind turbines of the Savonius type, but the invention finds an application mainly in wind turbines whose blades comprise membranes and are rotatably mounted around an axis. extending in a direction having a vertical component.

Wind turbines of the rotary wing type thus comprise a vertical shaft on which are mounted, pivoting around respective axes, a plurality of blades with membranes.

Provision can be made to control the angular position of these membranes, or not. Wind turbines of the panemon type, known for a long time, thus have membranes each stretched on a structure mounted freely in rotation around its respective axis, and one stopper per structure, so that these membranes thus offer resistance to the wind over an angular range 180°.

The document US2014/0178216 thus describes a system comprising a vertical shaft, two horizontal support planes, axes extending vertically so as to form spacers between these two support planes and blades rotatably mounted on these respective axes. Stops limit the angular range of free mounting in rotation of each of these blades, thus making it possible to increase the angular range of resistance to the wind.

However, there is a need for a simpler and more efficient cross-flow turbine system.

A cross-flow turbine system is proposed, comprising

a shaft extending longitudinally in an axial direction,

a plurality of arms mounted on the shaft and extending longitudinally in directions having radial components, for example radially,

a plurality of blades, each blade being mounted on a respective arm, free to rotate around an axis extending in a direction having a component parallel to the axial direction of the shaft, for example the axial direction, and

for each blade, an abutment device, defining a first abutment position and a second abutment position limiting the rotational movements of said blade between said first and second abutment positions, so that the corresponding blade is free to rotate on a angular range of at least 70°, this value being included, and of at most 100°, this value being excluded, said abutment device being arranged and installed such that the angle between the first abutment position and the direction tangential around the shaft attached to the axis of rotation of the blade is between 35° and 55° (in absolute value) and that the angle between the second stop position and the tangential direction is between 35° and 55° (in ultimate value).

Indeed, in the document cited above, the stops are distributed in a particularly asymmetrical way relative to the tangential direction, one corresponding to an angle of 50° with the radial direction (i.e. 40° in absolute value with the tangential direction ), the other at an angle between 150° and 165° (i.e. between 60° and 75° with the tangential direction).

By modifying the distribution of the stop positions in this way, the passive range can be reduced and the efficiency of the turbine can be significantly increased.

The turbine system is set in motion by a transverse flow of fluid, for example of liquid, for example by the flow of liquid from the tides, or of gas, for example of the wind.

At least one (and preferably each) blade can have a rotational movement only, around the corresponding axis, or alternatively a movement composed of (at least) a rotation and another movement such as a translation.

Advantageously, at least one (and preferably each) abutment device can be arranged and installed so that the corresponding blade is free to rotate over an angular range of at least 80°, this value being included, and of at most 100°, this value being excluded, advantageously at most 95°.

Advantageously, at least one (and preferably each) abutment device can be arranged and installed so that the angle between the first abutment position and the tangential direction is between 40° and 55° (in absolute value), advantageously between 45° and 55° (in absolute value).

Advantageously, at least one (and preferably each) abutment device can be arranged and installed so that the angle between the second abutment position and the tangential direction is between 40° and 55° (in absolute value), advantageously between 45° and 55° (in absolute value). Advantageously, at least one (and preferably each) abutment device can be arranged and installed so that the corresponding blade is free to rotate

- over an angular range between 90°, this value being included, and 100°, this value being excluded, advantageously between 90° and 98°, these values being included, advantageously between 90° and 95°, these values being included, by example between 90° and 92°, these values being included, in particular in the case of a wind turbine intended to be used with a gaseous fluid such as air; the efficiency can then tend towards the theoretical Betz limit for fluid velocities of less than 7 m/s;

- over an angular range varying between 90°, this value being included, and 100°, this value being excluded, advantageously between 95° and 99°, these values being included, in particular in the case of a tidal turbine intended to be used with a liquid fluid, such as water.

In one embodiment, at least one (and preferably each) blade can be rigid, and for example comprise a plate, for example made of aluminium.

Advantageously, at least one (and preferably each) blade can comprise a flexible membrane, for example made of fabric of natural fibers (cotton for example), fabric of synthetic fibers (polyamide for example), composite fabric (linen polyester for example ). The flexible membrane is not necessarily woven, we can for example use a natural isotropic membrane (leather for example), an isotropic polymer membrane (neoprene for example), etc.

The turbine system can thus be simpler to adapt, manufacture, repair, etc. than blades requiring the use of molds for their production (for example blades in plastic, metal, composite materials, etc.). We also gain in efficiency, and the differential drag can be optimized without neglecting the lift.

Advantageously, at least one (and preferably each) blade can comprise a structure supporting the corresponding flexible membrane.

Advantageously, at least one (and preferably each) blade extends in a plane normal to the longitudinal direction of the shaft over a distance representing at least one third of the distance between the shaft and the corresponding axis, advantageously at least 40% of this distance, and advantageously at most 150% of this distance. This further increases efficiency.

The invention is not limited to a particular form of abutment(s).

For example, provision can be made for the blade to define a cavity, receiving one end of the corresponding arm, between two walls forming abutments, thus limiting the angular range of rotation of the blade.

We can provide magnets in opposite sign, one of which is mounted on the blade and the other on the corresponding arm, and which repel each other with increasing force when the blade approaches the end of the angular range of free rotation, which can make it possible to dampen abutments.

One could alternatively provide flexible linear elements, for example slightly elastic, of the rope, string or tensioner type, each fixed on the one hand to a blade, on the other to the shaft or to an arm.

One could alternatively provide flexible elements, of the limit stop type, fixed to the contact zones between the blade and the arm.

Alternatively, more elaborate elements could be provided, with parts cooperating with each other, of the pneumatic cylinder or stop type, for example each fixed on the one hand to a blade, on the other to the shaft or to an arm.

In one embodiment, at least one (and preferably each) blade has a triangular or near-triangular shape – i.e. the blade defines three major discontinuities, forming angles between 30° and 120°, For example:

- between 50° and 70° especially if all the edges are straight, or even

- an angle between 100° and 120° and two angles between 40° and 30°, especially if all the edges are straight,

- between 40° and 60°, especially if the edges are shaped so that the blade is concave, or even

- an angle between 30° and 110°, and two angles between 0° and 60°, in particular in the case of at least one concave edge

In one embodiment, at least one edge of at least one (and preferably each) blade is concave, thus making it possible to better distribute the forces, making it possible in particular to limit the forces exerted near the corners of the triangle.

Advantageously, at least one concave edge can reach an adjacent edge with a curvature close to the local longitudinal direction of the adjacent edge (between 0° and 10° difference, 0° corresponding to the case of a perfect asymptote).

Advantageously, at at least one end of at least one concave edge, the flexible membrane can be fixed inside and/or at the end of a support rod corresponding to the adjacent edge.

A fixing inside the rod can be judicious in terms of distribution of the forces.

Advantageously, at least one (and preferably each) blade is mounted at one of these corners on the corresponding arm, for example the axis corresponding to this blade can be in the vicinity of this corner, for example at least 25% of the length of the blade in a plane normal to the longitudinal direction of the shaft, advantageously less than 10% of this length.

This limits the height of the blade at the level of the axis, and therefore the mass of the system.

Advantageously, the angle corresponding to this corner has a value between 100° and 120°, in particular if all the edges are straight.

It is also possible to provide for the angle corresponding to this corner to have a value between 30° and 110°, in particular if the edge opposite the corner is concave. The two other angles can then have a very low value, tending towards 0°, between 0° and 10°, or more.

Advantageously, at least one (and preferably each) blade may comprise a V-shaped structure comprising two support rods forming a wedge, the edge of the blade extending between the two free ends of the branches of the V being devoid of a support rod.

Advantageously, the blade is mounted on the arm corresponding to the level of the corner formed by these two support rods, for example at less than 25% of the length of the blade in a plane normal to the longitudinal direction of the shaft, advantageously at less than 10% of this length.

In one embodiment, these two support rods extend longitudinally in two respective directions symmetrical with respect to the plane normal to the longitudinal direction of the corresponding axis. By “symmetrical”, we mean here an angle difference of less than 20°, advantageously less than 10°, advantageously less than 5°.

Advantageously, for at least one (and preferably each) blade, the flexible membrane is supported by this V-shaped structure, and the edge of the flexible membrane extending between the two free ends of the branches of the V is a free edge.

Advantageously, this free edge is concave, thus making it possible to distribute the forces exerted on the branches of the V-shaped structure. The blade therefore has a generally triangular shape, with two straight edges and a concave edge.

In one embodiment, the structure can be reinforced by at least one additional support rod, extending for example from the corner towards the free edge (bat wing structure).

Advantageously, the longitudinal direction of the shaft can be collinear or form an angle of less than 20° with the gravity vector.

Advantageously, at least one (and preferably each) axis of rotation extends in a direction parallel to the longitudinal direction of the shaft or forming an angle of less than 20° with this direction.

In one embodiment, at least one (and preferably each) arm can be secured to a corresponding rod, without degree of freedom, this rod extending longitudinally in the direction of the axis of rotation of the blade. The corresponding blade is then rotatably mounted around this rod.

In one embodiment, at least one (and preferably each) blade can be secured, without degree of freedom, to a rod, extending in the direction of the axis of rotation of the blade, and rotatably mounted on the corresponding arm. The thrust of the fluid then causes the rotation of the shaft plus rod assembly around the longitudinal direction of the rod when the shaft rotates, until the blade reaches a stop position, then offering a catch to the wind (or more generally, to the fluid).

Advantageously, the turbine system may be devoid of blade support elements which would extend in planes, normal to the longitudinal direction of the shaft, distinct from the plane or planes normal to the longitudinal direction of the shaft occupied by arms. In other words, the system can comprise a single support plane (or interval of support planes in the case of arms extending obliquely with respect to the longitudinal direction of the shaft. The system can thus be lighter and more easily adaptable than the wind turbine described in the document described above.

The wind turbine system has no means of controlling the orientation of the blades. The blades are left free to rotate in the passive range.

There is further proposed a cross-flow turbine system, comprising a shaft extending longitudinally in an axial direction,
a plurality of arms mounted on the shaft and extending along directions having radial components, a plurality of blades, each blade being mounted on a respective arm, free to rotate about an axis extending along a direction having a component parallel to the longitudinal direction of the shaft, and for each blade, an abutment device, defining at least two abutment positions so that the corresponding blade is free to rotate over an angular range of less than 350°, advantageously less than 179°, advantageously less than 120°, for example between 60° and 115°, for example between 60° and 99°, said angular range being distributed symmetrically on either side of the tangential direction around the shaft attached to the axis of rotation of the blade. By “symmetrical” is meant here an angular deviation of less than 10°, this value being included, advantageously of less than 5°, this value being included.

The invention is now described with reference to the accompanying, non-limiting drawings, in which:

is a top view of an exemplary turbine system according to one embodiment of the invention.

is a perspective view of the example turbine system of Figure 1.

is a sectional view, in the plane normal to the longitudinal direction of the shaft, of part of the system of Figure 1.

shows the stop positions of this part of the system.

Identical references may be used to designate identical or similar elements from one figure to another.

Referring to Figure 1, a wind turbine system 10 comprises a shaft 1 extending longitudinally in a direction perpendicular to the plane of the sheet, in the direction of the gravity vector.

In Figure 1, the arrow 20 represents the direction of the wind.

In this embodiment, the cross-flow turbine is a vertical shaft wind turbine, but in an alternative embodiment it could be provided that the fluid driving the turbine is a liquid, for example water.

Three arms 2, 2', 2'' extend radially from this shaft 1, in a plane normal to the longitudinal direction of shaft 1, i.e. here in the plane of the sheet.

The arms 2, 2', 2'' are secured, without any degree of freedom, to the shaft 1.

The arms 2, 2', 2'' are distributed regularly over the circumference of the shaft 1, that is to say that they form angles of 120° between them.

Of course, more than three arms may be provided, for example four, five, six or more arms. The angles between adjacent arms are then reduced.

One can choose for these trees tubes, for example aluminum, wood, stainless steel, composite material or other.

These tubes, each supporting a corresponding 6, 6', 6'' blade alone, can be chosen with the mass to be supported so that, under the expected conditions of use:

- the deflection following the gravity vector is less than 5 millimeters, advantageously less than 1.5 millimeters;

- the deflection in the other directions is less than 20 millimeters, advantageously less than 5 millimeters.

These tubes can for example have an external diameter between 10 millimeters and 100 millimeters, advantageously between 20 millimeters and 40 millimeters, for example 30 millimeters, in particular in the case of aluminum tubes.

The thickness of the tubes, in particular in the case of aluminum tubes, can vary between 1 millimeter and 5 millimeters, advantageously between 1.5 millimeters and 2 millimeters.

At the end of each arm 2, 2', 2'' is mounted a support 12, 12', 12'' defining an orifice 13, 13', 13''. Each orifice receives a rod, not shown, secured to the corresponding blade.

The system also includes three blades 6, 6', 6''. As illustrated in FIG. 1, each blade extends, in the plane of the sheet, over a distance d representing at least one third of the distance between the shaft 1 and the corresponding axis, here over approximately 80% from this distance.

As illustrated in Figure 2, each blade has a generally triangular shape.

A V-shaped structure comprising two rectilinear rods 70, 70', 70'', 71, 71', 71'' forming an angle of almost 90° makes it possible to support a flexible membrane 8, 8', 8''.

Edge 72, 72', 72'' corresponding to the space between the branches of the V is a free edge, not directly supported by a rod.

This 72, 72', 72'' edge is concave.

It is possible to stretch the flexible membranes more or less, depending on the expected winds.

The straight rods 70, 70', 70'', 71, 71', 71'' forming a corner, here a triangular piece 21, 21', 21'', for example in aluminium, wood or molded plastic.

As illustrated in Figure 3, this triangular piece 21, 21', 21'' defines a cavity 14 receiving a portion of the respective support 12, 12', 12''.

This cavity is delimited by two walls 15, 16, against which the support 12 comes into abutment.

In this example, an elastic element 25, 26 has been installed on each of these walls 15, 16 to partially absorb the energy of the impact during the abutment.

These elastic elements 25, 26 can for example be clipped into the support 12.

These stops 25, 26 make it possible to limit the angular range of rotation of the blade 6.

To return to Figure 1, these rotations are free, the wind turbine system 10 being devoid of means for controlling the orientation of the blades 6, 6', 6''.

In figure 1, the 6" blade is in its free rotation range (also called passive range) and its direction is that of the wind, according to arrow 20.

On the other hand, the blade 6' is in abutment, offering a resistance to the wind which tends to cause the shaft 1 to rotate. When the arm 2' reaches an angular position such that the blade 6' finds itself aligned with the direction of the wind, this blade 6' in unstable equilibrium tilts and then finds itself in abutment against a second abutment, in a position close to that of the blade 6 in figure 1.

These two stops are arranged so that the range of free rotation (corresponding to the angle P in Figure 1) is distributed symmetrically around the tangential direction T, T', T'', attached to the axis of the blade 6, 6', 6'' in the reference frame rotating around the shaft 1 (see figure 4).

In this example, the free rotation range extends over an angle P of 90°.

In this example, the angle E between the blade when abutting against the abutment 26 (case of the blade 6 in FIG. 1) and the tangential direction T is 45°, and the angle I between the blade when abutting against the stop 25 (case of blade 6' in FIG. 1) and the corresponding tangential direction T' is 45°.

FIG. 4 is a sectional representation in which this part of the system has been artificially superimposed when in the first abutment position (like the blade 6' in FIG. 1) and in the second abutment position (like the blade 6 in FIG. 1).

The range of free rotation P has an angular value equal to the sum of the angle I and the angle E. In this example, these angles I, and E are equal in absolute value, so that the passive range is symmetrically distributed around the tangential direction.

Claims (10)

A cross-flow turbine system (10), comprising
a shaft (1) extending longitudinally in an axial direction,
a plurality of arms (2, 2', 2'') mounted on the shaft and extending in respective directions having radial components,
a plurality of blades (6, 6', 6''), each blade being mounted on a respective arm, and being free to rotate around an axis extending in a direction having a component parallel to the longitudinal direction of the 'TREE,
for each blade, a stop device (21, 21', 21''), defining a first stop position and a second stop position limiting the rotational movements of said blade between said first and second stop positions, so that the corresponding blade is free to rotate over an angular range (P) of at least 70°, this value being included, and of at most 100°, this value being excluded, said stop device is arranged and installed so that the angle (I) between the first stop position and the tangential direction around the shaft attached to the axis of rotation of the blade (T, T', T'') is between 35° and 55°, in absolute value, and that the angle (E) between the second stop position and the tangential direction is between 35° and 55° in absolute value. A cross-flow turbine system (10) according to claim 1, wherein at least one thrust device (21, 21', 21'') is arranged and installed such that the corresponding blade (6, 6', 6' ') is free to rotate over an angular range (P) of at least 80°, this value being included, and of at most 100°, this value being excluded. A cross-flow turbine system (10) according to claim 2, wherein
at least one stop device (21, 21', 21'') is arranged and installed so that the corresponding blade (6, 6', 6'') is free to rotate over an angular range (P) between 90° , this value being included, and 98°, this value being included. A cross-flow turbine system (10) according to any one of claims 1 to 3, wherein at least one thrust device (21, 21', 21'') is arranged and installed such that and
the angle (I) between the first stop position and the tangential direction (T, T', T'') is between 40° and 55° in absolute value and that the angle € between the second stop position and the tangential direction, i.e. between 40° and 55° in absolute value. A cross-flow turbine system (10) as claimed in any one of claims 1 to 4, wherein at least one blade (6,6',6'') comprises a flexible membrane (8,8',8''). A cross-flow turbine system (10) according to any one of claims 1 to 5, wherein at least one blade (6, 6', 6'') comprises a V-structure comprising two support rods (70, 70' , 70'' 71, 71', 71'') forming a corner (21, 21', 21''), the edge (72, 72', 72'') of the blade extending between the two free ends branches of the V being devoid of a support rod. A cross-flow turbine system (10) according to claim 6 when dependent on claim 5, wherein the flexible membrane (8, 8', 8'') is supported by said V structure, and the edge (72, 72', 72'') of the flexible membrane extending between the two free ends of the branches of the V is concave. A cross-flow turbine system (10) according to claim 6 or 7, wherein at least one blade (6, 6', 6'') is mounted at said corner on the corresponding arm (2, 2', 2' '), the axis corresponding to said blade being located in the vicinity of said corner, at less than 25% of the length of the blade in a plane normal to the longitudinal direction of the shaft. A cross-flow turbine system (10) according to any one of claims 1 to 8, wherein at least one blade (6, 6', 6'') extends in a plane normal to the longitudinal direction of the shaft over a distance (d) representing at least one third of the distance (d') between the shaft and the corresponding axis. A cross-flow turbine system (10) according to any one of claims 1 to 9, said turbine system being devoid of blade support members which extend in planes normal to the longitudinal direction of the shaft , distinct from the plane or planes normal to the longitudinal direction of the shaft occupied by the arms (2, 2', 2'').