GB2513832A

GB2513832A - Turbine apparatus

Info

Publication number: GB2513832A
Application number: GB1303755.1A
Authority: GB
Inventors: Bill Gilpin
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-03-04
Filing date: 2013-03-04
Publication date: 2014-11-12
Also published as: GB201303755D0

Abstract

A transverse axis fluid (e.g. wind) turbine 10 comprises a shaft 30 couplable to a power generator, a plurality of rotor blades 40, each having a first end 42 proximal to the shaft and a second end 44 distal from the shaft, and each defining first and second edges 46, 48 which extend between the first and second ends. First and second plates 50, 52 are provided at the first and second edges of the rotor blades such that the blades and plates define at least one fluid passage, and the distance between the plates defines a width of the fluid passage. At least one of the plates is non-planar such that the width of the, or each, fluid passage increases between the first and the second ends of the blades so that fluid flowing within the fluid passage is funnelled. The width of each blade may also increase between its first and second ends.

Description

Turbine Apparatus The present invention relates to transverse axis fluid turbine apparatus. In particular, but not exclusively, the invention relates to Savonius wind turbine apparatus.

Transverse axis turbines, such as vertical axis turbines, have a number of advantages over horizontal axis turbines. They are self starting and do not need to be manoeuvred and adjusted to account for wind direction. They also take up less space due to their construction and also because they can be packed closer together in a wind farm (there is less of a slowing effect on the surrounding air).

In an urban setting, they are far less obtrusive.

Savonius type wind turbines are one example of vertical axis turbines and have two (or sometimes three) scoop-like' rotor blades. Each blade is vertically oriented, arcuate about a vertical axis, and is arranged so that wind acts upon the inner surface of the concave blade but flows relatively unrestricted over the outer surface of the blade. The arrangement also results in two adjacent blades vertically funnels the wind towards the inner surface of another blade (the term "vertically funnel" in intended to mean that the adjacent vertical blades define a passage for wind and the distance between adjacent vertical blades decreases as wind travels up the passage). The arrangement results in turning of the blades. The top and bottom portions of the blades, and the housing, are conventionally planar and horizontal.

However, a conventional turbine of this type may not start easily if the wind direction is directly towards an edge of a blade and, once started, there are no convenient means of ceasing blade rotation. Also, conventional turbines tend to produce unwanted pulsations due to varying blade orientation. Furthermore, although wind is vertically funnelled, the horizontal flow of the wind is unaffected.

I

According to the present invention there is provided a transverse axis fluid turbine apparatus comprising: a shaft which is couplable to power generating apparatus; a plurality of rotor blades, each blade having a first end proximal to the shaft and a second end distal to the shaft, and each blade defining a first and a second edge which extend between the first and second ends; and a first plate member provided at the first edge of each rotor blade and a second plate member provided at the second edge of each rotor blade, wherein the blades and the first and second plate members define at least one fluid passage, the distance between the first and second plate members defining a width of the fluid passage, and wherein at least one of the first and second plate members is non-planar such that the width of the or each fluid passage increases between the first end and the second end of the blades so that fluid flowing within the fluid passage is funnelled.

The width of each blade may increase between the first end and the second end.

At least one of the first and second plate members may have a surface which is complementary to a surface circumscribed by the rotating blades.

The width of each blade may linearly increase between the first end and a second free end. At least one of the first and second plate members may have a surface adjacent to the blades which is conical so that it is complementary to a surface circumscribed by the rotating blade.

Alternatively, the width of each blade may geometrically increase between the first end and a second free end. At least one of the first and second plate members may have a surface adjacent to the blades which is convex or dome-shaped so that it is complementary to a surface circumscribed by the rotating blade.

One of the first and second edges may be normal to the axis of the shaft and the respective one of the first and second plate members may be planar and normal to the axis of the shaft. Preferably, each of the first and second edges is inclined relative to the axis of the shaft and each of the first and second plate members are non-planar. Preferably, the first plate member is identical to an inverted second plate member.

Alternatively, the width of each blade may be constant and at least one of the first and second plate members includes a slot for receiving the blade.

The transverse axis fluid turbine apparatus may comprise a vertical axis fluid turbine apparatus. The first plate member may comprise an upper plate member.

The second plate member may comprise a lower plate member. The upper and lower plate members may be configured to horizontally funnel the fluid flowing within the fluid passage.

The transverse axis fluid turbine apparatus may comprise a Savonius wind turbine apparatus.

The rotor blades may be equispaced around the shaft. The apparatus may have two rotor blades.

The apparatus may comprise a plurality of sets of blades. A first and a second set of blades may be separated by the first and a third plate member. A fourth plate member may be provided adjacent to the second set of blades.

The width of each blade of the second set of blades may increase between the first end and the second end. At least one of the third and fourth plate members may be non-planar and complementary to a surface circumscribed by the rotating blades of the second set.

Alternatively, the width of each blade may be constant and at least one of the third and fourth plate members includes a slot for receiving the blade.

The third plate member may be identical to an inverted first plate member. The third plate member may be identical to the second plate member. The fourth plate member may be identical to an inverted third plate member. The fourth plate member may be identical to the first plate member.

One or more of the plate members may be fixedly mounted to the shaft. The plate members may be connectable to the adjacent blade. One or more peg members may be provided at the first and second edges of each blade, each peg member being receivable in a corresponding aperture or recess provided at the adjacent plate member.

Each plate members may be provided with an arrangement of peg receiving apertures or recesses such that the plate member can connect to the first or the second edge of a blade.

The blades of the first set may be rotationally offset from the blades of the second set.

Each blade may be arcuate about the shaft axis to define a concave and a convex blade surface. The convex blade surface may be substantially continuous so that fluid flows relatively unrestricted over the surface. The concave blade surface may be substantially discontinuous so the resistance to fluid flow is increased when fluid flows over the surface.

The concave blade surface may include one or more discontinuities to create local regions of turbulent flow. The discontinuities may comprise recesses, channels, craters, ribs, protrusions or the like. Alternatively or in addition, the concave blade surface may be roughened to provide the discontinuities. The dimensions of the discontinuities may be predetermined to suit the operating characteristics of the apparatus.

The apparatus may include stopping means for selectively ceasing rotation of the rotor blades. The stopping means may comprise means for blocking the fluid passage.

The blocking means may comprise a shutter device provided circumferentially around the blades. The shutter device may comprise a plurality of blind members which are rotatable between a first position in which the fluid passage is accessible to fluid and a second position in which the fluid passage is blocked.

The blocking means may include an actuator such as a motor. The actuator may be remotely operable.

Alternatively or in addition, the stopping means may comprise a brake member which is operatively coupled to the shaft or a locking member adapted to engage with one or more of the blades or plate members to prevent rotation.

The apparatus may include solar power generating apparatus such as one or more solar panels.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of an apparatus mounted to a roof of a building with blocking means (a) open and (b) closed; Figure 2 is another perspective view of an apparatus mounted to a roof of a building; Figure 3 is a (a) front view and (b) perspective view of portions of the apparatus of Figure 1; Figure 4 is a schematic plan view of the apparatus of Figure 1; Figure 5 is a front view of a portion of the blocking means of the apparatus of Figure 1; Figure 6 (a) and (b) is a front view of another portion of the blocking means of the apparatus of Figure 1; Figure 7 is a perspective view of a portion of a blade and plate member of the apparatus of Figure 1; and Figure 8 (a) to (d) is a side view of a concave surface of a blade of the apparatus of Figure 1.

Figure 1 shows a transverse axis fluid turbine apparatus in the form of a Savonius wind turbine 10. The turbine 10 is fixed to a base 12 which has an inclined base surface l4so that it can be mounted to the roof 100 of a building.

Within the base 12 is power generating means (not shown) which can be used to provide power to the building.

The turbine 10 has blocking means in the form of a shutter device 20 which is explained in detail below. In Figure 1 (a) the shutter device 20 is open while in Figure 1 (b) the shutter device 20 is closed.

Figure 2 is similar to Figure 1 except that the turbine 10 is fixed to a bracket 14 which has an angled leg 16 for mounting to the roof 100 of the building.

Figure 3 better shows certain components of the turbine 10. The turbine 10 comprises a shaft 30 which is coupled to the power generating apparatus such that rotation of the shaft 30 generates power. Provided around the shaft 30 are two sets of rotor blades 40. These sets are arranged in a stacked relationship.

The blades 40 of the first set are rotationally offset from the blades 40 of the second set. This reduces pulsations in operation and the turbine 10 is also better at self starting since there is always a blade 40 close to being normal to the wind direction.

Each set of blades 40 comprises two individual blades 40 which are diametrically opposed on the shaft 30. Each blade 40 has a first end 42 which is proximal to the shaft 30 and a second end 44 which is distal to the shaft 30. The blades 40 define a first edge 46 and a second edge 48 which extend between the first and second ends. The blades 40 are arcuate about the axis of the shaft 30 and define a concave blade surface 60 and a convex blade surface 62.

Provided above and below each set of blades 40 are plate members.

Considering the upper set of blades 40, a first plate member 50 is provided adjacent the first edge 46 and a second plate member 52 is provided adjacent the second edge 48 of the rotor blade 40. Considering the lower set of blades 40, a third plate member 54 is provided adjacent the first edge 46 and a fourth plate member 56 is provided adjacent the second edge 48 of the rotor blade 40.

The blades 40 are not directly connected to the shaft 30. Rather, they are connected to the respective plate members. This allows the blades 40 to define a central gap 64 as shown in Figure 4 which schematically illustrates operation of the turbine 10.

The blades 40 and the plate members define fluid passages. Wind 110 enters each fluid passage to act upon the concave surface 60 of a blade 40. The wind is vertically funnelled due to the arrangement of the blades 40 and at least a portion of the wind 110 is also funnelled through the gap 64 to act upon the concave surface 60 of the other blade 40. The applied force of the wind 110 causes rotation of the plate members, since the blades 40 are connected to the plate members, causing the shaft 30 to rotate (in direction 66 in Figure 4) to generate power.

As shown best in Figure 3 (a), the width of each blade 40 geometrically increases between the first end 42 and the second end 44. The first and second plate members are non-planar and dome-shaped. They are therefore complementary to a theoretical surface circumscribed by the rotating blades. The dome-shaped plate members result in the width of each fluid passage increasing between the first end and the second end of the blades 40. This causes fluid flowing within the fluid passage to be horizontally funnelled which improves the efficiency of the apparatus.

In an alternative embodiment, the width of each blade could be constant and the dome-shaped plate members could be provided with a slot for receiving the blade. This would fix the blades 40 relative to the plate members and still have the effect of varying the width of the fluid passage.

The turbine 10 of the invention has a number of parts which are easy to produce.

Both the blades 40 and the plate members can be made from plastic such as by injection moulding. For connection of the blades 40 to the plate members, as shown in Figure 7, each blade 40 can be provided with a number of pegs 70 at the first and second edges of the blade 40, and each plate member can be provided with a corresponding aperture 72.

The blades 40 are all identical and so only one mould is required. The plate members are also identical, although some are inverted in use, and so one mould is required for them. The plate members can be provided with an arrangement of apertures 72 so that the plate member can connect to the first or the second edge of a blade 40. In Figure 7, this arrangement is a "figure of eight". This arrangement would in use leave a number of the apertures exposed and it may be that these discontinuities can reduce the performance of the turbine 10. There are a number of solutions to this such as covering or filling the exposed apertures. Another solution is forming recesses on the underside of the plate members which have a thin recess base provided by the upper surface of the plate member. During installation, the desired apertures for the particular orientation of blade can be formed by breaking through the thin base, the bases of the other recesses remaining in place so there are no discontinuities.

The convex blade surface 62 is formed to be smooth and so substantially continuous so that air flows relatively unrestricted over the surface. On the other hand, the concave blade surface 60 is roughened so that it is substantially discontinuous. This increases the resistance to air flow when wind flows over the surface. The concave blade surface 60 could include other discontinuities to create local regions of turbulent flow such as recesses, channels, craters, ribs, protrusions or the like. Figure 8 (a) to (d) shows a number of possibilities but many more are possible.

The turbine 10 includes stopping means for selectively ceasing rotation of the rotor blades 40. In the embodiment shown, this comprises means for blocking the fluid passage.

The turbine 10 includes a shutter device 20 which is provided circumferentially around the blades 40 and plate members. As shown in Figures 5 and 6, the shutter device 20 has a number of blinds 22 which are rotatable between a first position in which the fluid passage is accessible to fluid and a second position in which the fluid passage is blocked. Each blind 22 is rotatably attached to a support column 80 and a worm gear shaft 82 by a collar 24 which has a number of internal protrusions 26 which engage with the thread of the worm gear shaft 82.

A motor 84 is connected to a motor gear 86 which, when operated, rotates a geared ring 88 which in turn rotates a gear 90 on the worm gear shaft 82. This causes the worm gear shaft 82 to rotate which rotates the blinds 22 between the open and closed positions.

The present invention provides a turbine 10 which is more efficient due in part to horizontal funnelling of the wind 110 and the use of discontinuities at the concave blade surface. The turbine 10 is easy to produce. The turbine 10 is also better at self starting and at smoothing unwanted pulsations due to varying blade orientation. The turbine 10 can also be "switched off".

Whilst specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention.

Claims

Claims 1. A transverse axis fluid turbine apparatus comprising: a shaft which is couplable to power generating apparatus; a plurality of rotor blades, each blade having a first end proximal to the shaft and a second end distal to the shaft, and each blade defining a first and a second edge which extend between the first and second ends; and a first plate member provided at the first edge of each rotor blade and a second plate member provided at the second edge of each rotor blade, wherein the blades and the first and second plate members define at least one fluid passage, the distance between the first and second plate members defining a width of the fluid passage, and wherein at least one of the first and second plate members is non-planar such that the width of the or each fluid passage increases between the first end and the second end of the blades so that fluid flowing within the fluid passage is funnelled.
2. An apparatus as claimed in claim 1, wherein the width of each blade increases between the first end and the second end.
3. An apparatus as claimed in claim 1 or 2, wherein at least one of the first and second plate members has a surface which is complementary to a surface circumscribed by the rotating blades.
4. An apparatus as claimed in claim 2, wherein the width of each blade linearly increases between the first end and a second free end.
5. An apparatus as claimed in claim 4, wherein at least one of the first and second plate members has a surface adjacent to the blades which is conical so that it is complementary to a surface circumscribed by the rotating blade.
6. An apparatus as claimed in claim 2, wherein the width of each blade geometrically increases between the first end and a second free end.
7. An apparatus as claimed in claim 6, wherein at least one of the first and second plate members has a surface adjacent to the blades which is convex or dome-shaped so that it is complementary to a surface circumscribed by the rotating blade.
8. An apparatus as claimed in any preceding claim, wherein one of the first and second edges is normal to the axis of the shaft, and the respective one of the first and second plate members is planar and normal to the axis of the shaft.
9. An apparatus as claimed in any of claims 1 to 7, wherein each of the first and second edges is inclined relative to the axis of the shaft and each of the first and second plate members are non-planar.
10. An apparatus as claimed in claim 9, wherein the first plate member is identical to an inverted second plate member.
11. An apparatus as claimed in claim 1, wherein the width of each blade is constant and at least one of the first and second plate members includes a slot for receiving the blade.
12. An apparatus as claimed in any preceding claim, comprising a vertical axis fluid turbine apparatus.
13. An apparatus as claimed in claim 12, wherein the first plate member comprises an upper plate member, and the second plate member comprises a lower plate member, and wherein the upper and lower plate members are configured to horizontally funnel the fluid flowing within the fluid passage.
14. An apparatus as claimed in any preceding claim, comprising a Savonius wind turbine apparatus.
15. An apparatus as claimed in any preceding claim, comprising a plurality of sets of blades.
16. An apparatus as claimed in claim 15, wherein a first and a second set of blades are separated by the first and a third plate member.
17. An apparatus as claimed in claim 16, including a fourth plate member provided adjacent to the second set of blades.
18. An apparatus as claimed in claim 16 or 17, wherein the width of each blade of the second set of blades increases between the first end and the second end.
19. An apparatus as claimed in claim 18, wherein at least one of the third and fourth plate members is non-planar and complementary to a surface circumscribed by the rotating blades of the second set.
20. An apparatus as claimed in any of claims 16 to 19, wherein the third plate member is identical to an inverted first plate member.
21. An apparatus as claimed in any of claims 16 to 20, wherein the third plate member is identical to the second plate member.
22. An apparatus as claimed in any of claims 16 to 21, wherein the fourth plate member is identical to an inverted third plate member and identical to the first plate member.
23. An apparatus as claimed in any preceding claim, wherein one or more of the plate members is fixedly mounted to the shaft.
24. An apparatus as claimed in any preceding claim, wherein one or more plate members are connectable to the adjacent blade.
25. An apparatus as claimed in claim 24, wherein one or more peg members is provided at the first and second edges of each blade, each peg member being receivable in a corresponding aperture or recess provided at the adjacent plate member.
26. An apparatus as claimed in claim 25, wherein each plate member is provided with an arrangement of peg receiving apertures or recesses such that the plate member can connect to the first or the second edge of a blade.
27. An apparatus as claimed in any of claims 15 to 26, wherein the blades of the first set are rotationally offset from the blades of the second set.
28. An apparatus as claimed in any preceding claim, wherein each blade is arcuate about the shaft axis to define a concave and a convex blade surface.
29. An apparatus as claimed in claim 28, wherein the convex blade surface is substantially continuous so that fluid flows relatively unrestricted over the surface.
30. An apparatus as claimed in claim 28 or 29, wherein the concave blade surface is substantially discontinuous so the resistance to fluid flow is increased when fluid flows over the surface.
31. An apparatus as claimed in claim 30, wherein the concave blade surface includes one or more discontinuities to create local regions of turbulent flow.
32. An apparatus as claimed in claim 31, wherein the discontinuities comprise one or more of recesses, channels, craters, ribs and protrusions.
33. An apparatus as claimed in claim 31 or 32, wherein the discontinuities comprise a roughened concave blade surface.
34. An apparatus as claimed in any preceding claim, including stopping means for selectively ceasing rotation of the rotor blades.
35. An apparatus as claimed in claim 34, wherein the stopping means comprises means for blocking the fluid passage.
36. An apparatus as claimed in claim 35, wherein the blocking means comprise a shutter device provided circumferentially around the blades.
37. An apparatus as claimed in claim 36, wherein the shutter device comprises a plurality of blind members which are rotatable between a first position in which the fluid passage is accessible to fluid and a second position in which the fluid passage is blocked.
38. An apparatus as claimed in any of claims 34 to 37, wherein the stopping means comprises a brake member which is operatively coupled to the shaft.
39. An apparatus as claimed in any of claims 34 to 38, wherein the stopping means comprises a locking member adapted to engage with one or more of the blades or plate members to prevent rotation.