NZ200333A - Wind turbine unit - Google Patents

Description

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N.Z. No.

NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION "IMPROVED TURBINE." .pAT^rroma 19 APR 1982 mm RECEIVE I, KENNETH JOHN COBDEN, an Australian citizen of 369 Deakin Avenue, Mildura, Victoria 3500 Australia do hereby declare the invention, for which I pray that a Patent may be granted to me , and the method by which it is to be performed, to be particularly described in and by the following statement:- 2. 2 00333 This invention relates to a fluid turbine, more particularly to a wind turbine although it may also be driven by other fluids sucVi as water.

BACKGROUND OF THE INVENTION Units for extracting the power from the wind have been known for centuries for driving mills, pumping water and the like. However these were very inefficient and had to be large in order to produce the required power.

Of recent years turbines havr: been developed in order to achieve greater efficiency from smaller units. Australian Patent number 513,247 discloses a wind turbine assembly having a rotor with a plurality of vanes in radially spaced relation to the axis, and flow controlling duct means to conduct a radial outflow of air against the vanes, the turbine having an aero-foil surface formed on an inlet duct, the vanes being situated in a low pressure area at the trailing edge of the aero-foil.

Australian Patent Application number 213,391/77 discloses 20. a turbine rotor having vanes mounted in a convergent-divergent duct, flow channels through the duct wall controlling the boundary layer.

Australian Patent number 492,087 shows a wind turbine having a duct in which is mounted stator and rotor blades. . it is an object of this invention to provide an improved wind turbine having advantages over the known art, in that it is more effective in converting the wind energy into motive power. . is It i s a effective further- object to provide a wind turbine which in delivering power from winds of low velocity. 3. 200333 SUMMARY OF THE INVENTION There is provided,according to the invention there io provided a fluid turbine unit to deliver power extracted from a moving fluid, the turbine having a turbine wheel mounted for rotation about an axis parallel to the fluid 5. flow, a plurality of vanes carried by said turbine wheel, a housing having in radial cross-section an aero-foil section, said vanes being situated in a passage through the aero-foil section at a position corresponding generally to the centre of lift of the aero-foil section whereby the 10. fluid flows through the passage to a lower pressure area of the aero-foil section to act on the turbine vanes.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a turbine according to the invention.

. Figure 2 is a cross-section view of the turbine.

Figure 3 is a diagramatic-sectional view of the invention. Figure 4 is a diagramatic part-sectional view of the vanes on the rotor, and Figure 5 is a perspective view of one vane.

. DESCRIPTION OF THE PREFERRED EMBODIMENT * Referring to the drawings there is shown a turbine 1 having a rotor 2 mounted on a shaft 3 supporting a bearing 4. Bearing 4 is supported on a frame 5, the turbine 1 being mounted on a shaft supported in a bearing 7. The . drive from the turbine wheel 2 can in this embodiment be by a friction wheel 8 attached to a drive shaft 9 which a passes downwardly through pedestal 6 and from which motive power may be obtained. 4. n ,'i n 7 7 7 ,i 0 U J J J The turbine wheel 2 carried a plurality of vanes 10 to which attached a forward fairing 11.

The turbine 1 also includes a hollow aerodynamically shaped body 12, a tail portion 13 being provided so that 5. the turbine unit will be quickly orientated into the prevailing air flow.

Turning now to Figure 3 there is shown an aero-foil section 14 having an upper surface 15, lower surface 16, leading ec^ge 17 and trailing edge 18. As is known with at.ro . aroo-foil sections, there is a reduced pressure formed over the upper surface and an area or portion at which the centre of pressure is considered to act. If a duct or passage 19 is formed through the aero-foil section at the centre of pressure, the air flow forming the reduced pressure 15. above the aero-foil will cause a flow of fluid through the passage into the area of reduced pressure. This concept is utilised in the present invention and it will be seen that the fairing 11 merges into the housing ,12 to form an aero-foil shape, the fairing 11 being curved in an 20. aero-foil section.

The turbine wheel 2, is also provided with a conical deflecting surface 20 which also is mounted on the shaft 3 and joins to the turbine wheel adjacent to the vanes.

% The vanes 10 are attached to the turbine wheel and 25. extend forwardly in cantilever fashion, the vanes carrying at their forward end the fairing 11 which thus rotates with the vanes. „As shown in Figures 4 and 5 the vanes 10 are formed in this example of sheet metal with end flanges 21 by which the vanes are mounted on the turbine 30 wheel 2 and to which the fairing is attached. It has been found that each of the vanes subtends an angle in the V r 200333 order of 8 to 16 degrees, but preferably 12 degrees and it is preferred that each vane has chord length in the vicinity of 100mm at least? for it is well known in the model aircraft art that this is the minimum chord length which is required to achieve satisfactory lift and performance.

Each of the vanes is shaped so that the leading edge is straight for approximately one third of its length along the line angle A-B, and similarly the trailing edge is straight for approximately one third of its length along the line angle B-C.

The chord line A-C is preferably situated between 50 and 6 0 degrees but more particularly 56 degrees from the radial line at C and the leading edge angle A-B is situated between 30 and 40 degrees from the chord line, more particularly 37 degrees, with the trailing edge line B-C being situated between 75 and 85 degrees, more particularly 78 degrees from the radial line at C.

The leading edge of each vane is on the same radius as the trailing edge of_the vane ahead of it. With the vanes so arranged,! the point of highest position of the aero-foil section of the vane, that is the point on the aero-foil \ (indiicafod generally ou X ) section which is furthest from the chord line/, is situated. J ,.(indicate* by y) generally directly opposite the trailing edge/of the preceding vane.

Thus taking the area between the vanes from the trailing edge of one vane to the highest point of the next trailing vane, the total area between all the vanes is approximately 2h times less than the inlet area, but the total area of the vane exhaust around the circumference of the turbine, is equal to the inlet area.

In this way it can be seen that the air flowing over the turbine unit creates a low pressure area at the exhaust of the vanes, and thus the air in passing through the vanes into this low pressure area causes -the turbine wheel to rotate. - . u/< f „ v- - ,-n\ 2003 6 In rotating, the nose fairing also rotates, and this rotation it is believed causes a layer of air to trail or rotate with the inlet fairing thus causing a rotating mass of air which in effect extends the aero-foil shape of the fairing, and thus creates an aero-foil shape of greater depth which enhances the low pressure area behind the rotating inlet fairing and so creates a greater low pressure area into which the air will exhaust.

As the inlet area of the turbine is equal to the exhaust area of the vane exhaust around the circumference of the turbine, there is no back pressure created, but in effect the opposite occurs due to the fact that the vanes exhaust the air into the low pressure area of the aero-foil section.

It will be seen also that due to the positioning of the vanes the forces acting on the vanes over the whole length of the vane are all acting at the same radius, and the forces are thus tangential over the whole length of the vane at the maximum radius so that a greater turning effect is achieved.

The edges of the vanes are mounted to extend generally parallel to the axis of the turbine, the vanes being i formed in an aero-foil section, and mounted with the vanes flltir af*- / being inclined so that fcfe leading edges w at a lesser -their radius than trailing edges. /'<" \V\ : v.-6W0VfS84V',1! In the alternative embodiment, the inlet fairing may not he attached to the vanes, but maybe mounted on a spider or the like attached to an axial shaft, but in this embodiment the radial attachments from the shaft to the fairing would interfere with the air flow, and also the advantage of the rotating inlet fairing would not be achieved.

The turbine unit can be used for supplying any motive power either driving an electrical generator, hydraulic pump, or mechanically to any desired unit requiring a motive power. For example an electrical generator or a hydraulic pump may be mounted directly or through gearing in the turbine housing itself.

The unit could be provided for pumping water in remote areas, providing electrical power to a direct power source or for charging batteries or the like. For example it can be mounted on sailing craft, yachts and the like to provide electrical power for lighting, cooking and communications.

The unit would also operate in water and could be used in areas of flowing water such as streams for the -ration of electric power. 8? - (/'

Claims (5)

8. 200333 WHAT I CLAIM IS:

1. A fluid turbine unit to deliver power extracted from a moving fluid, the turbine having a turbine wheel mounted for rotation about an axis parallel to the fluid flow, a plurality of vanes carried by said turbine wheel, a 5. housing having in radial cross-section an aero-foil section, said vanes being situated in a passage through the aero-foil section at a position corresponding generally to the centre of lift of the aero-foil section whereby the fluid flows through the passage to a lower pressure 10. area of the aero-foil section to act on the turbine vanes.

2. A fluid turbine unit as defined in Claim 1 wherein said vanes are of aero-foil shape each having its chord line parallel to the plane of the turbine wheel and inclined to the tangent of the turbine wheel, the vanes 15. extending from the turbine wheel parallel to said axis.

3. A fluid turbine unit as defined in Claim 2 wherein said turbine vanes are attached at their free end to an aero-foil shaped inlet fairing, the inlet fairing and the housing forming the aero-foil section, the inlet fairing 20. rotating with the turbine wheel so that in operation the rotating fairing induces an enlarged artificial aero-foil section to increase the aero-foil affect on the moving fluid.

4. A fluid turbine unit as defined in any one of Claims 1 25. to 3 wherein the fluid turbine unit is a wind turbine unit, the housing having a stabilising tail, and being mounted on a pedestal for rotation about a vertical axis. 200333 9. 5. A fluid turbine unit as defined in Claim 3 where the vanes are formed of pressed metal each having a straight leading edge and a straight trailing edge the vanes being curved to aero-foil shape and positioned with the trailing 5. edge of a leading vane co-radial with the leading edge of the following vane to form a constricted passage with the -total j_all pdF iKa. iu/bioe. outlet area between'the vanes I being equal to the inlet area of the turbine unit. 6. A fluid turbine unit as defined in Claim 4 and 0. including drive means to engage the turbine wheel, the drive means driving a shaft extending through the pedestal and coinciding with the said vertical axis. 7. The fluid turbine unit substantially as hereinbefore described with reference to and as illustrated in the

5. accompanying drawings. KENNETH JOHN COBDEN By his Patent Attorneys HENRY HUGHES LIMITED