Impulse air turbine arrangement for use with a reversing bi-directional air flow in a wave power plant
View Patent ↗An impulse air turbine arrangement for use with a reversing bi-directional air flow in a wave power plant comprises an axial flow turbine rotor with volutes mounted one each side of the turbine rotor to direct the reversing air flow to and from the turbine rotor. Each volute extends circumferentially with respect to the turbine axis between a radially outer opening and a radially inner opening. The radially outer opening is oriented for input/output of the air in a tangential direction and the radially inner opening is oriented axially to impinge/receive swirling air flow onto/from the turbine rotor.
1. An impulse air turbine arrangement for use with a reversing bi-directional air flow in a wave power plant, the impulse air turbine arrangement comprising:
an axial flow turbine rotor mounted for rotation about a turbine axis;
volutes mounted on each side of the turbine rotor to direct the reversing air flow to and from the turbine rotor, each volute extending circumferentially with respect to the turbine axis between a radially outer opening and a radially inner opening;
the radially outer opening being oriented for input/output of the air in a tangential direction and the radially inner opening being oriented axially to impinge/receive swirling air flow onto/from the turbine rotor.
2. An impulse air turbine arrangement according to claim 1 , wherein a cross-sectional flow area of each volute decreases from the radially outer opening towards the radially inner opening.
3. An impulse air turbine arrangement according to claim 1 , wherein the radially inner opening of each volute is substantially annular in cross-section.
4. An impulse air turbine arrangement according to claim 1 , wherein each volute comprises a pair of axially spaced walls and a plurality of radially and circumferentially extending flow control vanes located between the axially spaced walls.
5. An impulse air turbine arrangement according to claim 4 , wherein the radially inner opening of each volute is provided at a substantially central region of the wall adjacent to the turbine rotor.
6. An impulse air turbine arrangement according to claim 4 , wherein at least one of the walls of each volute is movable axially with respect to the turbine axis to vary a flow area through each volute.
7. An impulse air turbine arrangement according to claim 4 , wherein one or more of the flow control vanes is movable to vary its sweep angle.
8. An impulse air turbine arrangement according to claim 4 , wherein one or more radially adjacent flow control vanes cooperate to define one or more radially and circumferentially extending flow corridors within each volute, each flow corridor comprising a radially outer circumferential opening and a radially inner circumferential opening.
9. An impulse air turbine arrangement according to claim 8 , wherein the radially inner circumferential opening of each flow corridor is positioned radially outwardly of the axially oriented radially inner opening of each volute.
10. An impulse air turbine arrangement according to claim 1 , wherein each volute comprises a circumferentially extending duct.
11. An impulse air turbine arrangement according to claim 1 , further comprising a turbine casing surrounding the turbine rotor and extending axially between the volutes.
12. A wave power plant comprising a wave energy converter for providing a reversing bi-directional air flow and an impulse air turbine arrangement according to claim 1 arranged to be driven by the reversing bi-directional air flow and coupled to an electrical generator to drive the electrical generator.