Turbine with radial inlet and outlet rotor for use in bidirectional flows
The present invention relates to a turbine which can absorb energy from bi-directional reversing flows, as is the case of ocean wave energy converters. In the periphery of the bladed rotor ( 2 ) of the turbine there are two openings ( 5, 6 ) through which the fluid alternately enters, or exits from, the rotor, the outward flow being radially centrifugal and the inward flow being radially centripetal. The turbine stator comprises two sets of guide vanes ( 7, 8 ) for alternately directing the bi-directional reversing flow to, and from, the rotor, and two ducts ( 9, 12 ) disposed between the rotor and the guide vanes and extending radially beyond the guide vanes. Two stator arrangements are considered. In both arrangements, the inlet guide vanes deflect the inward flow and impart a circumferential swirl component in the same direction as the normal rotational direction of the rotor. In one of the arrangements, the twin guide vane set ( 18, 19 ) is close to the rotor periphery ( 5, 6 ) and can be moved axially so that it guides the inward flow into the rotor and does not intersect the outward flow. In the other arrangement, both sets of guide vanes ( 7, 8 ) are axially fixed and are radially offset from the rotor.
1. A turbine arrangement for bi-directional reversing flow comprising:
a rotor with blades disposed circumferentially around said rotor,
a stator with guide vanes;
an axis, said rotor rotatably mounted about the axis;
said blades forming flow channels from rotor entry to rotor exit, said rotor having on its outer periphery two apertures axially offset from each other;
a first set of said guide vanes having a setting angle and being circumferentially disposed about the axis and located at a greater radius with respect to the corresponding rotor aperture in the path of the flow incoming to it or coming out of it;
a first duct connecting the first set of guide vanes with the corresponding rotor aperture;
a second set of said guide vanes having a setting angle and being circumferentially disposed about the axis and located at a greater radius with respect to the corresponding rotor aperture in the path of the flow incoming to it or coming out of it;
a second duct connecting the second set of guide vanes with the corresponding rotor aperture, wherein the entrance of fluid into the rotor through any of the two apertures is centripetal with a swirl imparted by the first set of guide vanes in the same direction as the normal direction of rotation of the rotor, and
wherein the exit of fluid from the rotor through any of the two apertures is centrifugal, said rotor blades in the vicinity of each of the two rotor apertures being inclined, in relation to an axial plane, at an angle of direction opposite a normal direction of rotation of the rotor.
2. The turbine arrangement according to claim 1 wherein said first duct is externally disposed in the alignment of the first set of guide vanes and connects it to an outside fluid space.
3. The turbine arrangement according to claim 1 wherein said second duct is externally disposed in the alignment of the second set of guide vanes and connects it to an outside fluid space.
4. The turbine arrangement according to claim 1 wherein the two sets of guide vanes of the stator are movable in axial translation, in such a way that each guide vane set can be inserted into the flow incoming to the rotor and be removed from the flow coming out of the rotor.
5. The turbine according to claim 1 wherein, in the stator, the setting angle of the guide vanes of each set is adjustable and is controlled by a mechanism of ring and articulated rods as commonly applied in the wicket gate system of Francis and Kaplan hydraulic turbines.
6. The turbine according to claim 1 wherein the channels formed by the rotor blades are externally bound along the whole periphery:
by a casing rigidly connected to the rotor blades,
or by a casing forming part of the stator.
7. A turbine arrangement for bi-directional reversing flow comprising:
a rotor with blades disposed circumferentially around said rotor;
a stator with guide vanes;
an axis, said rotor rotatably mounted about the axis;
said blades forming flow channels from rotor entry to rotor exit, said rotor having on its outer periphery two apertures axially offset from each other, the entrance of fluid into the rotor through any of the two apertures being centripetal and the exit of fluid from the rotor through any of the two apertures being centrifugal;
a first set of said guide vanes having a setting angle and being circumferentially disposed about the axis and located at a greater radius with respect to the corresponding rotor aperture in the path of the flow incoming to it or coming out of it;
a first duct connecting the first set of guide vanes internally with the corresponding rotor aperture and externally with an outer fluid space, wherein said first duct is externally disposed in the alignment of the first set of guide vanes and connects it to an outside fluid space;
a second set of said guide vanes having a setting angle and being circumferentially disposed about the axis and located at a greater radius with respect to the corresponding rotor aperture in the path of the flow incoming to it or coming out of it;
a second duct connecting the second set of guide vanes internally with the corresponding rotor aperture and externally with an outside fluid space, wherein said second duct is externally disposed in the alignment of the second set of guide vanes and connects it to an outside fluid space;
wherein the two sets of guide vanes of the stator are movable in axial translation in such a way that each guide vane set can be inserted into the flow incoming to the rotor and be removed from the flow coming out of the rotor.
8. The turbine according to claim 7 wherein, in the stator, the setting angle of the guide vanes of each set is adjustable.
9. The turbine according to claim 7 wherein the channels formed by the rotor blades are externally bound along the whole periphery by a casing rigidly connected to the rotor blades or by a casing forming part of the stator.
10. A turbine arrangement for bi-directional reversing flow comprising:
a rotor with blades disposed circumferentially around said rotor,
a stator with guide vanes;
an axis, said rotor rotatably mounted about the axis;
said blades forming flow channels from rotor entry to rotor exit, said rotor having on its outer periphery two apertures axially offset from each other,
a first set of said guide vanes having a setting angle and being circumferentially disposed about the axis and located at a greater radius with respect to the corresponding rotor aperture in the path of the flow incoming to it or coming out of it;
a first duct connecting the first set of guide vanes internally with the corresponding rotor aperture and externally with an outer fluid space, wherein said first duct is externally disposed in the alignment of the first set of guide vanes and connects it to an outside fluid space;
a second set of said guide vanes having a setting angle and being circumferentially disposed about the axis and located at a greater radius with respect to the corresponding rotor aperture in the path of the flow incoming to it or coming out of it;
a second duct connecting the second set of guide vanes internally with the corresponding rotor aperture and externally with an outside fluid space, wherein said second duct is externally disposed in the alignment of the second set of guide vanes and connects it to an outside fluid space;
a casing that bounds externally the channels formed by the rotor blades along the whole periphery that is either a casing rigidly connected to the rotor blades or is a casing forming part of the stator, wherein the entrance of fluid into the rotor through any of the two apertures is centripetal with a swirl imparted by the first set of guide vanes in the same direction as the normal direction of rotation of the rotor, and
wherein the exit of fluid from the rotor through any of the two apertures is centrifugal, said rotor blades in the vicinity of each of the two rotor apertures being inclined, in relation to an axial plane, at an angle of direction opposite a normal direction of rotation of the rotor.
11. The turbine arrangement according to claim 10 wherein the two sets of guide vanes of the stator, are movable in axial translation, in such a way that each guide vane set can be inserted into the flow incoming to the rotor and be removed from the flow coming out of the rotor.
12. The turbine according to claim 10 wherein, in the stator, the setting angle of the guide vanes of each set is adjustable.