ROTOR FOR HYDROKINETIC TURBINE AND RELATED HYDROKINETIC TURBINE

Description

DESCRIPTION Title: ROTOR FOR HYDROKINETIC TURBINE AND RELATED TURBINE HYDROKINETICS Technical field of the invention The present invention relates to a rotor for a hydrokinetic turbine and a related hydrokinetic turbine. State of the art In the context of electricity production, hydrokinetic turbines are known, i.e. 5 devices structured to convert the kinetic energy of a water flow, such as for example the flow of a river or the motion of waves or tides, in mechanical energy rotational. Such rotational mechanical energy is typically used to generate electricity, for example through a generator attached to the turbine shaft. Summary of the invention 10 The term “rotor” refers to the moving part, typically rotating around its own axle, of a driving machine, such as a hydrokinetic turbine. The terms "perpendicular" and "orthogonal" respectively mean a perpendicularity and a substantial orthogonality between two elements, including both the ideal case in which these elements are arranged in relation to each other so as to form a 15 right angle, both more frequent cases in which the two elements are arranged in relation to each other so as to form an angle that deviates from the right angle (e.g. included in a interval of +- 15°, more preferably +- 10°, with respect to the right angle) but still in a negligible or irrelevant manner to the functioning of this solution. The term "parallel" means a substantial parallelism between two elements, 20 including both the ideal case in which such elements are arranged relative to each other in so as to form a zero angle, both more frequent cases in which the two elements are arranged one with respect to the other so as to form an angle that deviates from the zero angle (e.g. (included within a range of +- 15°, more preferably +- 10°, from the zero angle) but in any case in a negligible or irrelevant way for the functioning of the 25 present solution. The terms “radial” and “axial” are used with reference to a perpendicular direction and a direction parallel to the axis of rotation of the shaft rotor center. The term “circumferential” is used with reference to a centered annular development 30 in the axis of rotation of the central shaft of the rotor. In the above context of electricity production, the Applicant found that known hydrokinetic turbines have some drawbacks and / or can be improved in one or more aspects. For example, the Applicant has found that hydrokinetic turbines can be 5 improved in terms of performance, such as energy generation efficiency electric. The Applicant therefore faced the problem of improving the performance of a turbine hydrokinetics, for example in terms of electricity generation efficiency and / or performance. 10 According to the Applicant the above problem is solved by a turbine rotor hydrokinetic, and a related hydrokinetic turbine, in accordance with the attached claims and / or having one or more of the following characteristics. In one aspect, the invention relates to a rotor for a hydrokinetic turbine. Preferably said rotor comprises a central shaft and one or more blades integral with said 15 central shaft. Preferably each blade has a development with at least one component radial with respect to the said central shaft. Preferably each blade comprises a first end portion, adjacent to said central shaft, and a second end portion, opposite to said first end portion along said development of said blade. 20 Preferably each blade comprises a working surface that extends at least at said second end portion, said work surface being intended to be hit by an operating fluid having a direction of advancement to generate thrust on said blade. Preferably each blade comprises a dorsal portion facing the opposite direction 25 with respect to said work surface. Preferably, said dorsal portion has a tapered development proceeding in moving away from said work surface. According to another aspect the invention relates to a hydrokinetic turbine comprising a support frame and the rotor according to the present invention rotationally fixed to 30 said support frame. Preferably said turbine also comprises means for generating electrical energy (eg alternator) connected to said rotor to generate electrical energy from a rotation of said rotor around an axis of said central shaft. According to the Applicant, the working surface of each blade, intended to be hit by the operating fluid (e.g. a water flow) with a given direction of advance to generate thrust on the blade represents the surface portion of the blade which, thanks to upon interaction with the fluid, it allows the blade to rotate and consequently the central shaft around its axis to produce mechanical rotational energy from 5 can typically be converted into electrical energy. When using a hydrokinetic turbine, therefore during the rotation of the rotor around the axis of the central shaft by the moving operating fluid, the Applicant observes that the dorsal portion of the blade represents a portion of the blade that contrasts, in general, the flow motion of the working fluid, thus opposing the rotation of the 10 rotor. This happens for example in the case of a rotor completely immersed in the fluid (e.g. immersed hydrokinetic turbines), where the dorsal portion of the blade is located necessarily move, during the rotation of the rotor, in the opposite direction to the direction of motion of the working fluid for at least one rotation section of the blade, or even in case of rotor only partially immersed (e.g. semi-immersed hydrokinetic turbines), where 15 the dorsal portion essentially represents the first portion of the blade to enter in contact with the operating fluid during the descent of the blade into the fluid following the rotation of the central shaft. Without wishing to limit itself to any theory, the Applicant believes that in both of the above cases the dorsal portion, resisting the motion of the fluid, generates a counter-thrust that opposes the desired rotation of the rotor, resulting in, 20 ultimately, in a decrease in efficiency in electricity generation. According to the Applicant, therefore, the dorsal portion having a tapered development moving away from the work surface allows you to obtain a profile having desired hydrodynamic qualities and therefore able to reduce the resistance that the dorsal portion of the blade opposes the fluid. In other words the dorsal portion with 25 tapered development allows for the creation of a dorsal edge capable of cutting through the water in the above cases where the dorsal portion is found to oppose the flow of the fluid, and thus limiting the hydrodynamic resistance of the dorsal portion of the blade. In this way it is possible to reduce the slowing effect of the rotor due to the motion of the blades when moving against the direction of the fluid, improving the 30 overall turbine performance, e.g. in terms of generation efficiency of electricity. The present invention in one or more of the above aspects may present one or more of the following: following favorite features. Preferably said central shaft comprises an axle, typically a central symmetry of the said central shaft and around which the central shaft rotates. Preferably said radial component of development of each blade is a component of main development of each blade. In other words, each blade has main development along the radial direction. This improves interaction with the operating fluid. 5 Preferably said work surface comprises at least one concave portion with concavity having a direction opposite to the said direction of advancement of the working fluid. In this context it is understood that the concavity of the concave portion of the surface working direction opposite to the direction of flow of the fluid for at least one operating angular position (preferably a continuous range of angular positions 10 operating) of the blade in its rotational trajectory around the axis of the central shaft during the rotation of the rotor, i.e. an angular position or range of positions angular in which the blade generates mechanical rotational energy under the action of the fluid operational. This increases the resistance to the fluid offered by the work surface. for the benefit of performance. 15 Preferably said concave portion comprises a first curvature along a axial direction. In other words, the concave position of the working surface has a curvature moving parallel to the axial direction. This encourages the interaction with the working fluid. Preferably said concave portion comprises a second curvature along a 20 radial direction. In other words, the concave position of the working surface has a curvature (also) moving parallel to the radial direction, for example in moving away from the central shaft. This encourages interaction with the fluid operating. Preferably said concave portion has a constant section, more preferably with 25 substantially C-shaped, moving along a section of the generating line of shape arched lying on a plane (substantially) perpendicular to said axial direction (i.e. to said axis of said central shaft). Preferably said section with shape substantially a C realizes said first curvature and said section of the generating line of arched shape realizes the said second curvature. Without wanting to limit ourselves to any theory, 30 the Applicant found that such shape of the concave portion of the surface of work allows to obtain the desired qualities of conversion of the fluid force into energy rotation mechanics. Preferably, said concave portion coincides with said working surface. In others terms the concave portion of the work surface occupies substantially the entire work surface. This further improves performance. Preferably, said work surface develops continuously from said first end portion to said second end portion of said blade. Thus the entire radial development of the blade is exploited to generate mechanical energy, 5 performance advantage. Preferably said dorsal portion is arranged at least partially, more preferably (substantially) entirely, corresponding to said surface of work. This further improves the hydrodynamic profile of the blade. Preferably, said dorsal portion develops continuously from said first portion 10 of the end to said second end portion of said blade. In this way it is improved further improve the hydrodynamic profile of the blade. Preferably said tapered development of said dorsal portion defines an edge dorsal having development with at least one radial component. In this way it is appropriately shaped according to the main development of the blade. 15 Preferably, the dorsal edge has its main development along the radial direction. In This further facilitates the shear effect of the dorsal portion on the fluid operating. Preferably each blade has a respective plane of symmetry arranged orthogonally to the said axis of the said central shaft. In this way the shape of the blade is 20 highly rationalized. Preferably a thickness of each blade measured between said working surface and said dorsal edge has a first (monotonically) increasing trend up to a maximum moving along said radial direction from said first end portion of the blade. Preferably said thickness of each blade has a second trend 25 (monotonically) decreasing moving along said radial direction from said maximum at the said second end portion. In other words, each blade has a thickening in correspondence with an intermediate portion of it moving radially along the development of the blade from the first end portion to the second end portion. In this way the structure of the blade is reinforced on one side and on the other, 30 in combination with the development with radial component of the dorsal edge, is achieved a substantially pointed profile with further improvement of the hydrodynamic qualities of the dorsal portion (to the advantage of even lower resistance of the blade to the fluid). Preferably said maximum is placed in a more proximal position to said second end portion of said blade with respect to said first end portion. In others terms the thickening of the blade is arranged more proximal to the free end of the blade. Without wanting to limit oneself to any theory, in this way the rotational inertia of the blade, to further benefit performance (e.g. uniformity of rotation speed a once a rotation speed of the regime is reached, even with any variations in 5 flow rate / velocity of the fluid -within a certain limit-). Preferably said rotor comprises a plurality of blades distributed along an entire useful axial development of said central shaft. In this way the arrangement is rational. By “useful axial development” of the shaft we mean an axial length of the shaft arranged directly in correspondence with the working fluid (i.e. shaft length 10 can be used to arrange blades). In other words, any extensions of the central shaft in addition to the light of the canal / river on which the turbine is located, they are not considered. Preferably, said plurality of blades comprises two or more groups of blades. Preferably each blade group comprises a respective plurality of blades arranged among themselves in sequence along said axial direction, more preferably for 15 substantially said entire useful axial development of said central shaft. Preferably each group of blades is arranged angularly equispaced from the remaining groups of blades of said plurality of blades with respect to said axis of said central shaft. In others terms, in the presence of two groups of blades, they are arranged with an angle between them equal to about 180°, in case of three groups of blades, the reciprocal angle is equal to about 120° and so on. 20 In this way the weight of the blades is distributed evenly along the shaft and / or rationally distribute the sections of the rotor rotation trajectory in which there are blades working in the fluid (i.e. blades that generate mechanical rotational energy). Preferably said respective plurality of blades of each blade group is distributed along said axial direction following a portion of the line having development (along said 25 shaft) with at least one circumferential component. In other words, the blades of each group are arranged on the tree so that they are not aligned with each other in a way purely axial, but progressively more and more staggered with respect to that direction (e.g. taking the first blade of a given group as a reference). In this way, the further improve the turbine performance as it is possible to ensure that there is 30 essentially always at least one blade working in the fluid as the rotor rotates. Preferably said portion of the line has a helical development with respect to said axis of said central shaft. This development has proven to be highly advantageous for realizing as described above. Preferably, the said helical development has a constant pitch. This simplifies the rotor construction. By “helical development pitch” we mean a distance between two distinct points belonging to the helical development and aligned with each other along the same generator. Preferably a step of said helical development is greater than or equal to 2.5, plus 5 preferably greater than or equal to 3, times said useful axial development of said shaft central, and / or less than or equal to 5.5, more preferably less than or equal to 5, times the useful axial development of the central shaft. This further improves efficiency. of rotor power generation. Preferably (for each group) a ratio between an axial distance between blades 10 consecutive ones belonging to the same group (e.g. taken in the center of the blade) and said development useful axial of the central shaft is greater than or equal to 8%, more preferably greater or equal to 10%, and / or less than or equal to 20%, more preferably less than or equal to 15%. This improves the rotor's energy production efficiency by optimising the density of the blades in relation to the useful development of the central shaft, for example avoiding 15 blades too thinly packed (not very efficient) or too thickly packed (equally inefficient as they generate a barrier to the operating fluid that would not impact in the desired way on the next set of blades). Preferably a ratio between an axial width of each blade (e.g. of said working surface, more preferably the concave portion) and said axial development 20 center shaft profit is greater than or equal to 3%, more preferably greater than or equal to 4%, and / or less than or equal to 7%, more preferably less than or equal to 6%. In This way the efficiency of the rotor is improved, for example by avoiding blades that are too thin (not not sufficiently robust, not efficient) and blades that are too wide (which can create side effects of fluid damming in a similar manner to that described above). 25 Preferably (for each group) a ratio between an axial distance between blades consecutive of the same group and a radial height of the blade is greater than or equal to the 20%, more preferably greater than or equal to 25%, and / or less than or equal to 40%, more preferably preferably less than or equal to 35%. This improves production efficiency. of rotor energy, for example by optimising the blade draft by reducing the effects 30 perturbations in the fluid that a blade can generate on adjacent blades. Preferably said turbine is a river turbine. Preferably, the turbine has a horizontal and transverse axis (with respect to the direction of operating fluid advancement). Preferably said support frame is shaped to be able to move said rotor with respect to said operating fluid along a direction having at least one component vertical, more preferably purely vertical. To this end the supporting frame can example include lifting equipment (e.g. hydraulic pistons, etc.) to be able to lift the rotor vertically above the fluid. This allows you to vary the height 5 of the rotor and / or its degree of immersion, for example when the fluid flow rate varies operational (typically confined to a river bed or canal), even to to be able to remove the rotor entirely from the fluid, for example to avoid possible damage in the event of floods and / or inundations due to impacts with debris transported by the operating fluid. 10 In one embodiment, said support frame is rigidly fixed to the ground. Preferably the support frame comprises a first portion. In one embodiment, said support frame coincides with said first portion. Preferably said rotor is rotationally fixed to said first portion (only) at a first axial end of said central shaft. 15 In one embodiment said support frame is floating in said working fluid. Preferably, said supporting frame comprises a second portion. In one embodiment said rotor is rotationally fixed to said second portion at a second axial end of said central shaft opposite to called first axial end. 20 Brief description of the figures Figure 1 shows a schematic perspective view of a hydrokinetic turbine. according to the present invention; Figure 2 schematically shows a further perspective view of the turbine in figure 1, 25 Figure 3 shows a top view of the turbine of Figure 1, Figure 4 shows a detail of the turbine in Figure 1. Detailed description of some embodiments of the invention The features and advantages of the present invention will be further clarified. from the following detailed description of some embodiments, presented for the purpose of 30 exemplifying and not limiting, of the present invention, with reference to the figures attached. In the figures with the number 99 a hydrokinetic turbine is globally indicated according to the present invention. For example, the turbine 99 comprises a support frame 90 and a turbine rotor 1. hydrokinetics according to the present invention. For example, the rotor 1 is rotationally fixed to the support frame 90. Turbine 99 is an example of a horizontal and transverse axis river turbine. In in other words a rotation axis of the rotor 1 is arranged horizontally and transversely 5 to a direction of advance 100 of a flowing working fluid (not shown) suitable for rotating rotor 1. For example, the rotation axis of rotor 1 coincides with the axis of a central shaft. 2 of the rotor, i.e. typically a central axis of symmetry and rotation of the shaft central. 10 For example, as shown in the figures, the turbine 99 can be installed in correspondence of a channel, artificial or natural, within which the aforementioned fluid flows operational, typically water. For example, the support frame 90 is stably and rigidly fixed to the ground and is It consists of a first portion 91 and a second portion 92 placed on opposite sides of the canal 15 central. For example, rotor 1 is rotationally fixed to both the first 91 and second portion 92 of the support frame 90, corresponding to a first and a second end portion of the central shaft 2 of the rotor 1, axially connected to each other opposite (i.e. arranged on opposite sides along a parallel axial direction 200 20 to the axis of the central shaft 2). In one embodiment, not shown, the support frame may be entirely or partially floating in the working fluid. For example, only one, or both of the first 91 and the second portion 92 of the support frame may be floating (the other can be fixed to the ground). 25 In one embodiment, not shown, the support frame may consist only of a single portion coinciding with one of the first and second portions. This single portion portion can be fixed to the ground or floating. For example, the support frame 90 has a lattice structure, each portion 91, 92 being made up of a pair of perforated plates joined together by a plurality of rods 30 rigid. For example, each of the first 91 and second portion 92 has a concave shape with concavity facing downwards (e.g. towards the ground). For example, the support frame 90 is shaped to be able to move the rotor 1 with respect to to the working fluid along a vertical direction. To this end the support frame 90 can example understand, typically corresponding to each first 91 and second portion 92, lifting means (not shown, e.g. hydraulic pistons, etc.) to be able to lift rotor 1 vertically above the working fluid. For example, the turbine 99 also includes means for generating electrical energy. 5 (not shown, e.g. including at least one alternator) connected to rotor 1 to generate electrical energy from a rotation of the rotor 1 around an axis (e.g. axis of central symmetry) of the central shaft 2. For example, the rotor 1 comprises the central shaft 2 and a plurality of integral blades 3 to the central shaft 2. 10 For example, each blade 3 has a main development along a radial direction 300 with respect to the central shaft 2. For example, each blade 3 has a respective plane of symmetry (not shown) arranged orthogonally to the axis of the central shaft 2. For example, each blade 3 comprises a first end portion 31, adjacent to the central shaft 2, and a second end portion 32, opposite to the 15 first portion of the end 31 along the main development of the blade 3. For example, each blade 3 comprises a working surface 4 which extends at least at the second end portion 32, the work surface 4 being intended to be hit by the operating fluid having a direction of advancement to generate thrust on the blade 3. 20 For example, the work surface 4 comprises at least one concave portion 5 with concavity having a direction opposite to the direction of flow 100 of the working fluid. In the present context and in the figures it is understood that the concavity of the concave portion 5 of the work surface 4 has a direction opposite to the direction of advancement of the operating fluid for a continuous range of operating angular positions of the blade 3 in the 25 its rotation path around the axis of the central shaft 2 during the rotation of the rotor, i.e. a range of angular positions in which the blade generates mechanical energy of rotation under the action of the operating fluid. This range of positions is an example operating angles coincide with a range of angular positions of the blade when it it is arranged substantially at a lower level than the central shaft level. 30 For example, the concave portion 5 coincides with the entire working surface 4 and comprises a first curvature along the axial direction 200 and a second curvature along a radial direction 300. In other words the concave potion 5 of the surface of work 4 (i.e. the entire work surface) presents an exemplary first curvature moving parallel to the axial direction 200 and a second curvature also moving parallel to the radial direction 300, for example in moving away from the central shaft. In more detail, the concave portion 5 has an exemplary constant section with shape substantially C-shaped moving along a segment T of the generating line (figure 4, in 5 (hatched) of an arched shape lying on a plane (not shown) perpendicular to the axis of the central shaft 2. For example, the section with a substantially C-shaped shape creates the aforementioned first curvature and the arc-shaped generating line section T creates the aforementioned second curvature. For example, the work surface 4 develops continuously from the first portion of 10 end 31 to the second end portion 32 of the respective blade 3. For example, each blade 3 also comprises a dorsal portion 6 facing opposite side to the respective work surface 4. For example, the dorsal portion 6 is arranged substantially entirely in correspondence of the work surface 4, in more detail developing exemplarily 15 with continuity from the first end portion 31 to the second end portion 32 of the respective blade 3. For example, the dorsal portion 6 has a tapered development proceeding in moving the respective blade 3 away from the working surface 4. For example, the tapered development of the dorsal portion 6 defines an edge 20 dorsal 61 having development with at least one radial component. For example the dorsal edge 61 has its main development along the radial direction 300. For example, a thickness of each blade 3 measured between the working surface 4 and the dorsal edge 61 has an initial increasing trend up to a maximum 62, moving along the radial direction 300 from the first end portion 31 of the blade 25 3, and a second decreasing trend moving along the radial direction 300 from maximum 62 at the second end portion 32. In other words each blade has a thickening in correspondence with an intermediate portion of it moving radially along the development of the blade 3 from the first end portion 31 to the second end portion 32. 30 For example, the maximum 62 is placed in a more proximal position to the second end portion 32 of the respective blade 3 with respect to the first end portion 31. In other words the thickening of the blade is located more proximal to the free end of blade 3 (see for example figure 4). For example, the plurality of blades 3 of the rotor 1 is distributed along an entire development useful axial SA of the central shaft 2. For example, the plurality of blades 3 is made up of four groups G of blades 3, each group G of blades 3 comprising exemplarily a respective plurality of blades 3 arranged in sequence along the axial direction 200 for substantially the entire 5 useful axial development SA of the central shaft 2. For example, each group G of blades 3 is arranged angularly equally spaced by remaining groups G of blades 3 of the plurality of blades with respect to the axis of the central shaft 2. In detail, the four groups G of blades 3 are exemplarily arranged with an angle between them equal to approximately 90° (centered on the axis of the central shaft 2). 10 Exemplarily the respective plurality of blades of each group G of blades 3 is distributed along the axial direction 200 following a portion of line L (shown in figure 2 for only one group G of blades) having development with at least one component circumferential. In more detail, the portion of the L line has an exemplary helical development with a pitch 15 constant (not shown) around the axis of the central shaft 2. For example, the pitch of the helical development of the portion of line L is equal to approximately 4 times the useful axial development SA of the central shaft 2. For example, a ratio between an axial distance D between 3 consecutive blades belonging to the same group G (e.g. grip at the centre of the blade) and the useful axial development 20 SA of the central shaft 2 is approximately 12% and a ratio between an axial width W of each blade 3 (e.g. of the concave portion) and the useful axial development SA of the shaft Central 2 is approximately 5%. For example, a ratio between the axial distance D between consecutive blades of the same group G and a radial height H of the blade is approximately 33%. 25 In use the hydrokinetic turbine 99 allows the production of electrical energy from energy rotation mechanics of rotor 1 thanks to the action of the moving operating fluid on the blades 3 of rotor 1. For example, the turbine 99 is operationally of the semi-submerged type, that is, rotor 1 is not entirely immersed in water but only partially, to a limited extent to the respective blades 3 when in a substantially lower portion of their respective 30 rotation path around the axis of the central shaft 2.

Claims

1. Rotor (1) for a hydrokinetic turbine (99), said rotor (1) comprising a central shaft (2) and one or more blades (3) integral with said central shaft (2), where each blade (3) has a development with at least one radial component with respect to said central shaft (2), where each blade (3) comprises a first end portion (31), adjacent to said central shaft (2), and a second end portion (32), opposite to said first end portion (31) along said development of said blade (3), where each blade (3) comprises a working surface (4) which develops at least in correspondence with said second end portion (32), said working surface (4) being intended to be hit by a working fluid having a direction of advancement (100) to generate a thrust on said blade (3), where each blade (3) comprises a dorsal portion (6) facing the opposite direction with respect to said working surface (4),and where said dorsal portion (6) has a tapered development proceeding away from said work surface (4)., 2. Rotor (1) according to claim 1, where said radial development component of each blade (3) is a main development component of each blade (3), and where said working surface (4) comprises at least one concave portion (5) with concavity having a direction opposite to said direction of advancement (100) of the working fluid.

3. Rotor (1) according to claim 2, where said concave portion (5) comprises a first curvature along an axial direction (200) and a second curvature along a radial direction (300).

4. Rotor (1) according to claim 2 or 3, where said concave portion (5) has a constant cross-section with a substantially C-shaped shape moving along a section (T) of an arc-shaped generating line lying on a plane substantially perpendicular to said axial direction (200).

5. Rotor (1) according to any of claims 2 to 4, where said concave portion (5) coincides with said working surface (4), where said working surface (4) extends continuously from said first end portion (31) to said second end portion (32) of said blade (3), where said dorsal portion (6) is arranged at least partially in correspondence with said working surface (4), and where said dorsal portion (6) extends continuously from said first end portion (31) to said second end portion (32) of said blade (3).

6. Rotor (1) according to any of the preceding claims, wherein said tapered development of said dorsal portion (6) defines a dorsal edge (61) having a development with at least one radial component, wherein a thickness of each blade (3) measured between said working surface (4) and said dorsal edge (61) has a first increasing trend up to a maximum (62) moving along a radial direction (300) from said first end portion (31) of the blade (3), and a second decreasing trend moving along said radial direction (300) from said maximum (62) to said second end portion (32), and wherein said maximum (62) is arranged more proximal to said second end portion (32) of said blade (3) than to said first end portion (31).

7. Rotor (1) according to any of the preceding claims, comprising a plurality of blades (3) distributed along an entire useful axial development (SA) of said central shaft (200), where said plurality of blades (3) comprises two or more groups (G) of blades (3), each group (G) of blades (3) comprising a respective plurality of blades (3) arranged in sequence along an axial direction (200), and where each group (G) of blades (3) is arranged angularly equispaced from the remaining groups (G) of blades (3) of said plurality of blades with respect to an axis of said central shaft (2).

8. Rotor (1) according to claim 7, where blades of said respective plurality of blades (3) of each group (G) of blades (3) are arranged in sequence along said axial direction (200) for substantially said entire useful axial development (SA) of said central shaft (2), where said respective plurality of blades (3) of each group (G) of blades (3) is distributed along said axial direction (200) following a portion of line (L) having a development with at least one circumferential component, where said portion of line (L) has a helical development with respect to said axis of said central shaft (2), where said helical development has a constant pitch greater than or equal to 2.5 times said useful axial development (SA) of said central shaft (2), and less than or equal to 5.5 times the useful axial development (SA) of the central shaft (2).

9. Hydrokinetic turbine (99) comprising a support frame (90) and the rotor (1) according to any of the preceding claims rotationally fixed to said support frame (90), wherein said hydrokinetic turbine (99) further comprises electrical energy generation means connected to said rotor (1) for generating electrical energy from a rotation of said rotor (1) about an axis of said central shaft (2).

10. Hydrokinetic turbine (99) according to claim 9, where said turbine (99) is a river turbine with a horizontal axis and transverse to said direction of advance (100) of said operating fluid, and where said support frame (90) is BIMS1B1 IT shaped to be able to move said rotor (1) with respect to said operating fluid along a direction having at least a vertical component.