Multi-use turbine

Abstract

A turbine and turbine system that can be used in multiple energy generating environments, comprises a turbine having a rotor 100 with a helical turbine blade 110 extending along a longitudinal axis ab

Description

The present invention relates to a turbine that can be used in multiple energy generating environments. A turbine is a rotating mechanical device that extracts energy from a flowing fluid. The turbine can then use the energy to drive a generator, which produces electrical power. Turbines are commonly used to generate renewable energy from natural sources, such as from wind or from flowing water in tides and in rivers. However, previously considered turbines for these purposes can be large and expensive to build. Furthermore, because of reliability problems and because many turbines have large numbers of parts, maintenance can also be costly and time consuming. Previously considered turbines are often noisy and so have to be situated in places that are away from residential areas. This sometimes means that their location is not optimised for performance. A further problem associated with previously considered wind turbines is that of bird strikes, which occur because of the size of the above-ground obstruction presented by the large blades of the apparatus, which are necessary to optimise efficiency. The size of the blades also requires that the turbine installations must be widely spaced, thereby using land inefficiently. Embodiments of the present invention aim to provide a multiuse turbine wherein the aforementioned problems are at least partly addressed. The present invention is defined in the attached independent claims, to which reference should now be made. Further, preferred features may be found in the sub-claims appended thereto. According to one aspect of the present invention, there is provided a turbine having a rotor part comprising a helical turbine blade extending along a longitudinal axis about which the rotor part rotates. The blade preferably extends helically along the longitudinal axis from a first, upstream end of the rotor, to a second, downstream end of the rotor. In a preferred arrangement, the blade comprises a foil. More preferably, the foil has a leading edge and a trailing edge. The foil may have an outer surface and an inner surface, with respect to the axis of rotation. The foil may have a foil profile that is shaped to create a differential fluid pressure across the inner and outer surfaces when the foil interacts with fluid flowing from the leading edge to the trailing edge. In a particularly preferred arrangement, the foil profile comprises an aerofoil or hydrofoil. Preferably, the maximum radius of the helical blade may vary across the length of the rotor. In a preferred arrangement, the rotor tapers towards at least one end, and more preferably tapers towards both ends. The rotor preferably has a front (upstream) end and a back (downstream) end with respect to the direction of fluid flow in use. Preferably the t ape r ed helical turbine blade comprises a taper at the front (upstream) end of the rotor. Preferably the diameter of the rotor increases from the front end towards a middle portion. This advantageously allows for the gradual increase of angular momentum of fluid around the blade, and reduces drag created by the blade. Preferably, the tapered helical turbine blade comprises a taper at the back end of the rotor. Preferably the diameter of the rotor decreases from a middle portion to the back end. This allows the blade to be balanced and reduces wake turbulence. The cross-sectional shape of the blade encourages lift and increases torque in the rotor during use. The tapered helical turbine blade may comprise a core member. This advantageously provides strength to the turbine blade. The core member may comprise steel or other structural materials . The tapered helical turbine blade may comprise a plastics material such as a polymer. The turbine may have a single helical turbine blade, which reduces cost of manufacturing and maintenance. Alternatively, the turbine may include a plurality of substantially concentric helically disposed blades. The present invention may extend to a turbine system, which may comprise a turbine mount. The turbine mount may comprise a monopile. In a preferred arrangement, multiple turbines / rotors may be mounted on a single monopile. The turbine system may include a generator that is arranged in use to be driven to generate electrical power by the rotation of the rotor. The rotor may be mounted on or connected to a drive shaft for the generator. The connection between the shaft and generator may be a keyed connection. When the turbine is used in a flowing gas, such as air, for example as a wind turbine, the upstream end of the rotor is placed into the prevailing wind. One or more orientation vanes may be provided to maintain the orientation of the rotor facing into the wind. When the turbine is used in a flowing fluid, such as tidal or river water, the upstream end of the rotor is positioned facing towards the direction from which the water flows and may be maintained in this orientation by the use of one or more orientation vanes, or else in the case of a tidal system, may have a fixed orientation so that the turbine is used to generate electricity only when the tide flows in one of two directions. According to another aspect of the present invention, there is provided a method of generating electrical power, the method including the steps of driving a generator by the rotation of a turbine having a rotor comprising a helical turbine blade, and exposing the blade to a flow of fluid. The turbine may be according to any statement herein. The flow of fluid may be obtained from wave, tidal, or wind sources. The rotor may be mounted so that an angle between 0-30° exists between the longitudinal axis of the rotor and the direction of incident fluid flow, more preferably an angle between 5-25° and still more preferably an angle of between 10-20°. This angle range is beneficial for maximising the rate of flow of fluid over the aerofoil shape, while increasing the torque. Where the flow of fluid is obtained from wave or tidal sources, the generator may be housed outside of the wave or tidal source, i.e., preferably above the water. Where the flow of fluid is from a wave source, the rotor may be arranged with its longitudinal axis substantially upright, more preferably substantially vertical. In this configuration, the orientation of the rotor is preferably so that the upstream end of the rotor is uppermost, so that it is the falling wave that drives the blade into rotation. Preferably, in this configuration, the rotor only rotates in one direction and is driven by the falling wave. This means that the rotor does not rotate when the water rises, meaning that there is no requirement for a self-rectifying power take-off. This simplifies the charging of the battery or batteries . When the turbine is mounted beneath a fixed structure, such as underneath a pontoon in a river or tidal flow, the generator is preferably situated on the pontoon and may be connected to the turbine by a universal joint. This beneficially allows the turbine to be compatible with standard marina pontoons. The turbine may be mounted on a buoy, which buoy may be an untethered buoy. The buoy may comprise a spar buoy. Spar buoys are known to be the most capable of surviving extreme weather in deep oceans. The buoy may comprise at least one propulsion device / thruster such as a propeller. The at least one thruster may be powered by at least one battery. The buoy may therefore be capable of movement in a body of water and may be capable of remaining stationary using the or each thruster to maintain a geographic position, for example countering the action of wind and currents. A locating means, for example GPS or other similar device, may be provided to enable location of the buoy e.g., so that it can detect its own position. The turbine may be arranged to charge one or more batteries, which batteries may be used to power the or each thruster. This beneficially allows the buoy to be untethered. As there is no need for the buoy to be connected to the ocean floor, less time and cost is required for installation of the buoy. The buoy may be arranged to suspend a detector / sensor device, such as a sonar device, beneath it. The device may be attached to the buoy by a tether, such as a filament, more preferably a nylon filament. The buoy may comprise a winch for raising and / or lowering the detector device. The buoy may be provided with a communications unit, such as a radio communications unit, and may have an antenna. Data can be collected from / by the buoy and communicated to a receiver. The buoy may be used as a subsea docking station and / or a recording station for an unmanned underwater vehicle or autonomous underwater vehicle (UUV / AUV) system. To this end, the buoy may be provided with a docking station for making mechanical and / or electrical connection to a UUV / AUV. The buoy can travel between set waypoints and / or loiter within a defined radius. The buoy may comprise a rotor which may comprise a helical turbine blade extending along a longitudinal axis about which the rotor rotates and wherein the rotor may be arranged in use to drive a generator for charging the battery. Preferably, the blade extends substantially helically along the longitudinal axis from a first end to a second end of the rotor. In a preferred arrangement, the blade comprises a foil. More preferably, the foil has a leading edge and a trailing edge. The foil may have an outer surface and an inner surface, with respect to the axis of rotation. The foil may have a foil profile that is shaped to create a differential fluid pressure across the inner and outer surfaces when the foil interacts with fluid flowing from the leading edge to the trailing edge. In a particularly preferred arrangement, the foil profile comprises an aerofoil or hydrofoil. Preferably, the maximum radius of the helical blade may vary across the length of the rotor. In a preferred arrangement, the rotor tapers towards at least one end, and more preferably tapers towards both ends. The rotor preferably has a front (upstream) end and a back (downstream) end with respect to the direction of fluid flow in use. Preferably the tapered helical turbine blade comprises a taper at the front (upstream) end of the rotor. Preferably the diameter of the rotor increases from the front end towards a middle portion. This advantageously allows for the gradual increase of angular momentum of fluid around the blade, and reduces drag created by the blade. Preferably, the tapered helical turbine blade comprises a taper at the back (downstream) end of the rotor. Preferably the diameter of the rotor decreases from a middle portion to the back end. This allows the blade to be balanced and reduces wake turbulence . The cross-sectional shape of the blade encourages lift and increases torque in the rotor during use. The tapered helical turbine blade may comprise a core member. This advantageously provides strength to the turbine blade. The core member may comprise steel or other structural material. The tapered helical turbine blade may comprise a plastics material such as a polymer. According to a further aspect of the present invention, there is provided a method of making a rotor part of a turbine, the method comprising forming a turbine blade so that the blade extends helically along a longitudinal axis about which the rotor rotates. The method may include forming the turbine blade by additive manufacture, such as 3D printing. Alternatively, or in addition, the blade may be moulded. The blade may be according to any statement herein. According to a further aspect of the present invention, there is provided a buoy including a turbine according to any statement herein. The invention may include any combination of the features or limitations referred to herein, except such a combination of features as are mutually exclusive, or mutually inconsistent. A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a schematic perspective view of a rotor including a helical turbine blade in accordance with an embodiment of the present invention; Figure 2 is a schematic cross-sectional view of part of the blade of Figure 1; Figure 3 is a side view of a wind turbine according to an embodiment of the present invention; Figure 4 is a perspective view of the turbine of Figure 3; Figure 5 is a side view of a tidal / river turbine according to another embodiment of the present invention; Figure 6 is a perspective view of the turbine of Figure 5; Figures 7a-7c are views of another embodiment of the present invention; Figures 8a-8c are views of a still further embodiment of the present invention; Figure 9 is a side view of another embodiment of the present invention; and Figure 10 is a sectional view of the embodiment of Figure 9. In one basic aspect, the invention provides a rotor for a turbine comprising a rotating helical aerofoil / hydrofoil. In another basic aspect, the invention provides a rotor for a turbine which comprises a tapered rotating helix. In some implementations, embodiments of the present invention provide a turbine and turbine system for use in power generation in a number of difference scenarios, including as a wind turbine, in a water course, such as a river or tidal flow, and in waves, such as sea or lake waves. Substantially the same type of rotor can be used in each scenario, with some adaptation, for example as to mounting and siting of the associated generator driven by the rotor. There follows a description of several preferred embodiments of the invention. Turning to Figure 1, this shows generally at 100 a turbine rotor according to an embodiment of the present invention. The rotor 100 is generally elongate and comprises a helical turbine blade 110 that extends axially along the rotor from a front, i.e., upstream, end 100a of the rotor to a back, ie downstream end 100b of the rotor. The longitudinal axis of the helix is the axis of rotation of the rotor. Integrally formed with the helical blade is a central, longitudinally extending shaft 120 that terminates, at the downstream end 100b with a keying feature 130 for engaging with a drive shaft of an electrical power generator (not shown) . The shape of the keying feature 130 may be any suitable for engaging with a cooperating feature in the generator. The rotor is of substantially consistent diameter in a mid-portion 100c, but tapers towards each end 100a and 100b. The rotor is conveniently made from plastics or other material, for example by moulding, e.g from a material such as polyurethane, or by additive manufacture such as 3D printing, e.g., from a material such as ABS . A strengthening core (not shown), for example of steel, may optionally be included within the central shaft. The helical blade 110 has a profile that has a spiral leading edge 110a and trailing edge 110b and has radially outer 110c and inner llOd surfaces. The blade has a profile that is shaped so that as fluid flows along the blade from the leading edge to the trailing edge, lift and torque are generated. Figure 2 shows the cross-sectional shape of the blade 110. Figure 3 shows an embodiment of wind turbine, generally at 1000, including a rotor as shown in Figures 1 and 2. The turbine 1000 actually employs two adjacent rotors, only one of which can be seen in this drawing. The turbine has the rotors 100 supported by a mounting 1100 which is itself mounted to a monopile 1200. In use the monopile may be secured to the ground. The mounting 1100 is free to rotate about a vertical axis on the monopile, so that it faces into the direction of the incident wind, represented by Arrow W. A vertical vane 1300 at the downstream end of the rotor ensures that this optimum orientation is maintained. The longitudinal axis of the rotor, represented by Line L is raised by an angle X to the wind direction. This angle is optimally chosen at around 10 degrees, as this has been found to produce the most efficient power generation from the wind. The rotor 100 is tapered towards its front i.e., upstream - end 100a to allow for the gradual increase of angular momentum of fluid around the blade, and to minimise drag and turbulence created by / around the blade. The rotor 100 also tapers towards its rear i.e., downstream end 100b so as to allow the blade to be balanced and to reduce wake turbulence. Figure 4 shows the turbine of Figure 3 in a perspective view, in which both of the rotors 100 can be seen. The apparatus could feature one, two or more such rotors, each driving a generator via the appropriate mechanical engagement (not shown). The generators G are conveniently housed in the cylindrical components directly aft of the rotors and directly ahead of the vanes. Figure 5 shows in side view a turbine 2000 for use in a flowing liquid, such as water from e.g., a tidal flow or a river (not shown) . There are two rotors 100 (only one is visible in this drawing). Drive shafts 2100 connect the rotors 100 to generators G mounted on a platform P above a water level indicated by WL. The rotors are mounted for rotation about a vertical monopile 2200. The direction of flow of the water is indicated by the Arrow F and a water vane 2300 ensures that the rotors are always facing into the flow. Figure 6 shows the turbine 2000 of Figure 5 in rear perspective view, in which both the rotors 100 can be seen. One, two or more such rotors may be employed. Figures 7a to 7c show respectively in above perspective, beneath perspective and cross-sectional views, an alternative arrangement of turbine 3000 for use with a fixed structure 3100, such as a pontoon of a marina. Again, the direction of flow of water is represented by Arrow F. As with previous embodiments, the rotor is orientated to face the flow of water, which may be a river, or may be a tidal flow. However, in this case, the turbine does not become reorientated when the water flows in the opposite direction, for example when the tide reverses. Rather, in this case, the turbine is unidirectional and generates electrical energy either when the tide floods, or when the tide ebbs. The rotor may also be used in generating electrical power from the action of waves, such as on a sea / ocean or lake. Figures 8a-8c show respectively side, above perspective and below perspective views of a further embodiment of turbine, generally at 4000 for this purpose. The rotor 100 is suspended substantially vertically below a platform P, itself above the water (not shown). The platform P also supports the generator G. The rotor is oriented so that its front end 100a (previously the upstream end) is uppermost, with the downstream end lowest in the water. The rotor is tethered either to a sea bed or to a spar buoy and its position is therefore fixed. Preferably, the rotor is fixed at its base to a monopile or similar via a pedestal (not shown) with bearings. When a wave passes, the rotor is driven into rotation by the falling wave. As it does so, the rotor drives the generator to produce electrical power. The generator is mounted vertically inside the housing on the platform P such that the keyed shaft on the end of the rotor mates directly onto the end of the generator. The rotor's axis of rotation need not be offset from vertical as the downward motion of the wave is already offset. With all of the above-described turbine systems the electrical power generated may be transmitted via cable to a grid connection or storage facility, or may be stored locally, for example in one or more batteries (not shown). Figures 9 and 10 show the rotor 100 as part of an untethered spar buoy shown generally at 3000, wherein the rotor is driven by wave action. The buoy 3000 has a main shaft 3500 to which is mounted a communications unit 3350 and an antenna 3300. Either or both of the communications unit and the antenna are preferably arranged to be above a water level (not shown) in use. The rotor is also mounted on the main shaft. The buoy 3000 has a housing 3100 in which is situated a battery 3120 and a winch 3140 for a tether 3145. The buoy may be driven through water by thrusters / propellers 3200 which are powered by the battery, thereby allowing the buoy to change its location by travelling within the water. The battery is itself charged by the generator G which is driven by the rotor 100. As such the spar buoy 3000 powers itself and does not require any docking for recharging. The buoy 3000 comprises a dipping sonobuoy 3400 at a distal end of the tether 3145, which may be raised and lowered by the winch 3140, itself also electrically powered. The buoy is provided with a docking station 3600 to allow for mechanical and / or electrical connections to a UUV / AUV (not shown). As an alternative, the rotor 100 may be mounted on a secondary shaft, not shown. The untethered spar buoy may be used for security / defence applications due to the option for docking with subsea UUVs that can scan and / or patrol subsea infrastructure without needing to surface. For example, the untethered buoy can be used to monitor subsea cables such as those used for energy and internet applications. The rotor described above is scalable, allowing its use in a variety of applications. Furthermore, the single rotor design can be used in multiple different mechanisms of generating electrical energy. The foil profile generates lift, which creates a low-pressure environment and adds buoyancy to the rotor. In water-based applications, the mounting of the turbine, and especially the generator, can conveniently be located above water. The shaft of the turbine may extend from the upstream or from the downstream end to accommodate the electrical generator(s) with or without the use of universal joints or similar linkages . In a tidal application, the turbine may be conveniently connected to a mounting, such as a monopile or similar, optionally with additional supports or other structure to ensure survivability of the installation. The turbine may be mounted so that it can be raised and lowered with, or by, the tide, as well as pivot to accommodate the changing direction of the tide. Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance, it should be understood that the applicant claims protection in respect of any patentable feature or combination of features referred to herein, and / or shown in the drawings, whether or not particular emphasis has been placed thereon.

Claims

1. A turbine having a rotor part comprising a helicalturbine blade extending along a longitudinal axis aboutwhich the rotor part rotates.

2. A turbine according extends substantially axis from a first endto Claim 1, wherein the blade helically along the longitudinal to a second end of the rotor.

3. A turbine according to Claim 1 or 2, wherein blade comprises a foil.

4. A turbine according to Claim 3, wherein the foil has a leading edge and a trailing edge, an outer surface and an inner surface, with respect to the axis of rotation, and a foil profile that is shaped to create a differential fluid pressure across the inner and outer surfaces when the foil interacts with fluid flowing from the leading edge to the trailing edge.

5. A turbine according to Claim 3 or 4, wherein the foil profile comprises an aerofoil or hydrofoil.

6. A turbine according to any of the preceding claims, wherein the maximum radius of the helical blade varies across the length of the rotor.7 . A turbine according to Claim 6, wherein the rotor tapers towards at least one end, and more preferably tapers towards both ends .A turbine according to anyof the preceding claims,wherein the blade comprises an axially extending coremember.

9. A turbine system, including a turbine according to any of Claims 1-8, and a turbine mount.

10. A turbine system according to Claim 9, including wherein the mount comprises a monopile.

11. A turbine system according to Claim 10, wherein multiple turbines are mounted on a single monopile.

12. A turbine system according to any of Claims 9-11, including a generator that is arranged in use to be driven to generate electrical power by the rotation of the rotor.

13. A turbine system according to Claim 12, wherein the rotor is mounted on or connected to a drive shaft for the generator.

14. A turbine system according to Claim 13, wherein the connection between the shaft and generator is a keyed connection.

15. A turbine system according to any preceding claim, wherein the turbine is mounted on a buoy.

16. A turbine system according to Claim 15, wherein the buoy is arranged to be untethered and comprises at least one thruster.

17. A turbine system according to Claim 16, wherein the at least one thruster is powered by a battery, the battery being charged by the generator.

18. A turbine system according to any of Claims 15-17, wherein the buoy comprises a detection device, such as a sonar device.

19. A turbine system according to any of Claim 15-18, wherein the buoy is used as a subsea docking station and / or a recording station for a UUV / AUV system.

20. An untethered self-propelled buoy comprising at least one battery, propulsion means powered by the battery and a rotor, wherein the rotor comprises a helical turbine blade extending along a longitudinal axis about which the rotor rotates and wherein the rotor is arranged in use to drive a generator for charging the battery.

21. An untethered self-propelled buoy according to Claim 20, wherein the blade extends substantially helically along the longitudinal axis from a first end to a second end of the rotor.

22. An untethered self-propelled buoy according to Claim 20 or 21, wherein the rotor is part of a turbine according to any of Claims 1-19.

23. A method of generating electrical power, the methodincluding thesteps of driving a generator by therotation of a turbine having a rotor comprising a helical turbine blade, and exposing the blade to a flow of fluid.

24. A method according to Claim 20, wherein the turbine is according to any of Claims 1-19.

25. A method according to Claim 20 or 21, comprising mounting the rotor so that an angle between 0-30° exists between the longitudinal axis of the rotor and the direction of incident fluid flow, more preferably an angle between 5-25° and still more preferably an angle of between 10-20°.

26. A method of making a rotor part for a turbine, the method comprising forming a turbine blade so that the blade extends helically along a longitudinal axis about which the rotor rotates.

27. A method according to Claim 23, wherein the method includes forming the turbine blade by additive manufacture, such as 3D printing.

28. A method according to Claim 23 or 24, wherein the blade is moulded.

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