"A TURBINE BLADE ASSEMBLY"

FIELD OF THE INVENTION

This invention relates to a turbine blade assembly. In particular, the invention relates to a turbine blade assembly driven by the wind. However, it should be appreciated that the turbine blade assembly may be driven by other fluids such as water. .

BACKGROUND OF THE INVENTION

Wind driven turbines have been used for many years.

Technology has advanced considerably from the old-fashioned windmill to today's complex large wind farm turbines found throughout the world. Though technology continues to advance, the same problems with wind turbines blade assemblies continue to exist. A barrier to the increase in efficiencies is the energy lost from the turbine through shedding of tip vortices, a form of turbulence. A result of this increased turbulence is often an increase in noise. As many wind turbines are located adjacent residential communities, any increase in noise is undesirable.

An advanced turbine blade assembly has a small hub in which blades extend outwardly and forwardly. The blades terminate in an outer ring cowl. In use, the hub is connected to a power generator with rotation of the turbine blade assembly generating electricity.

It has been found that locating a ring cowl on the end of the blades of a turbine blade assembly reduces noise. This is due to the ends of the individual blades being prevented from shedding tip vortices and creating turbulence in the air flow. However, the cowl itself can create additional turbulence and drag which is unwanted.

OBJECT OF THE INVENTION

It is an object of the invention to overcome and/or alleviate one or more of the above disadvantages and/or provide the consumer with a useful or commercial choice. SUMMARY OF THE INVENTION

The invention relates to a turbine blade assembly which includes an improved cowl.

In one form, the invention resides in a turbine blade assembly that is able to be driven by the wind, the turbine blade assembly comprising:

a hub;

a multiplicity of hub blades attached to and extending outwardly from the hub;

a first cowl attached to an end of the hub blades; wherein the first cowl is at an angle of between 9 and 15 degrees with respect to a central axis of rotation of the hub.

The turbine blade assembly may further include a multiplicity of cowl blades which are attached to the first cowl.

The turbine blade assembly may further include a second cowl attached to an end of the cowl blades.

The first cowl may be made from a flat plate. The second cowl may be made from a flat plate.

. The hub blades are typically arcuate in shape. The cowl blades are typically arcuate in shape.

Preferably, the first cowl is at an angle of between 10 and 14 degrees with respect to a central axis of rotation of the hub. More preferably, the first cowl is at an angle of between 11 and 13 degrees with respect to a central axis of rotation of the hub. Most preferably, the first cowl is at an angle of approximately 12 degrees with respect to a central axis of rotation of the hub.

Preferably, the second cowl is at an angle of between 10 and 14 degrees with respect to a central axis of rotation of the hub. More preferably, the second cowl is at an angle of between 11 and 13 degrees with respect to a central axis of rotation of the hub. Most preferably, the second cowl is at an angle of approximately 12 degrees with respect to a central axis of rotation of the hub.

The hub blades and the cowl blades may be separet or integrally formed.

The hub blades may or may not be the same length as the cowl blades. The hub blades may or may not be at the same angle as the cowl blades. The hub blades may be or may not be in alignment with the cowl blades. Similarly, the number of hub blades may or may not match the cowl blades.

Normally, the angle of the first cowl is substantially the same as the angle of the second cowl.

The hub may include a boss having a outwardly extending flange, the boss having an end wall and the flange having a side wall. A width of the end wall of the boss may be of a similar width to the side wall of the flange.

The turbine blade assembly may include a blade attachment member attached to the at least one hub blade and a hub attachment member attached to the blade attachment member and to the hub.

The hub attachment member may be attached to both the end wall of the boss and the side wall of the flange. The hub attachment member may extend at least half of the width of the end wall of the boss. Preferably, the hub attachment member extends substantially the width of the end wall of the boss.

The hub attachment member may extend at least half of the width of the side wall of the flange. Preferably, the hub attachment member extends substantially the width of the side wall of the flange.

The hub attachment member may also be attached to the hub blade.

The hub attachment member may be in the form of a hub attachment plate.

The hub attachment plate may form an angle of between 30 to 60 degrees with respect to the side wall of the flange. Preferably, the hub attachment plate may form an angle of between 40 to 50 degrees with respect to the side wall of the flange. More preferably, the hub attachment plate may form an angle of between 43 to 47 degrees with respect to the side wall of the flange. Most preferably, the hub attachment plate may form an angle of substantially 45 degrees with respect to the side wall of the flange.

The hub attachment plate may form an angle of between 30 to 60 degrees with respect to the end wall of the boss. Preferably, the hub attachment plate may form an angle of between 40 to 50 degrees with respect to the end wall of the boss. More preferably, the hub attachment plate may form an angle of between 43 to 47 degrees with respect to the end wall of the boss. Most preferably, the hub attachment plate may form an angle of substantially 45 degrees with respect to the end wall of the boss.

The blade attachment member is typically tubular. Normally, the blade attachment member has no corners. Preferably, the blade attachment member is circular or elliptical in transverse cross section.

A blade attachment hole may be formed with the hub blade to assist in attachment of the attachment member.

The blade attachment member may be attachment member may be attached substantially perpendicularly with the hub attachment plate.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will be described with reference to the accompanying drawings in which:

FIG. 1 shows a schematic view of a wind turbine which utilises a wind turbine blade assembly;

FIG. 2A shows a rear view of a wind turbine blade assembly according to FIG. 1 ;

FIG. 2B shows a side view of a wind turbine blade assembly according to FIG. 1 ;

FIG. 2C shows a perspective view of a wind turbine blade assembly according to FIG. 1 ;

FIG. 3 shows a detailed perspective view of a blade attached to a hub of the wind turbine blade assembly according to FIG. 2;

FIG. 4 shows a perspective view of a hub blade and a cowl blade connected to an inner and outer cowl shown in FIG.2; and FIG.5 shows a side view of the wind turbine blade assembly according to FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a schematic view of wind turbine 1 mounted on top of a platform 5. The wind turbine 1 includes a wind turbine blade assembly 10 which is attached to a power generator (not shown) located within a wind turbine housing 2. Details of the power generator and wind turbine housing 2 have not been discussed as this is common knowledge to a person skilled in the art.

FIGS. 2A to 2C show a perspective view of a wind turbine blade assembly 10 shown in FIG. 1. The wind turbine blade assembly 10 includes a hub 20, a series of hub blades 30, a series of cowl blades 40, a first cowl 50 and a second cowl 60.

The hub 20 is used to attach the wind turbine blade assembly 10 to a power generator. The hub 20 is formed from a boss 21 and a flange 22 as shown in FIG. 3. The flange 22 is attached to the boss 21 and extends outwardly from the boss 21. The boss 21 has an end wall 21A whilst the flange has a side wall 22A. The end wall 21 A and the side wall 22A are substantially perpendicular with respect to each other. The end wall 21 A and the side wall 22A are of similar width.

A generator attachment hole 23 is located through the boss 21 for attachment of the wind turbine blade assembly 10 to the power generator. There are also a.series of weight reducing holes 24 located through the boss 21 in order to reduce the weight of the hub 20.

Each of the hub blades 30 are arcuate in shape and are able to be driven by the wind. The hub blades 30 extend outwardly from the hub and are attached to the hub 20. The hub blades 30 are angled at approximately 45 degrees with respect to the hub 20. However, it should be appreciated that other angles may be used. The series of hub blades 30 terminate at and are joined to the first cowl 50.

FIG. 3 shows further details of hpw a hub blade 30 is attached to the hub 20. A blade attachment member 31 and a hub attachment plate 25 are used for this purpose. The blade attachment member 31 is in the form of a tubular pipe which is located within a blade attachment hole 32 located with the hub blade 30. The blade attachment member 31 is welded to the hub blade 30.

The hub attachment plate 25 is attached to the hub blade 30, the blade attachment member 31 and the hub 20. The hub attachment plate 25 is welded to the hub blade 30 adjacent a central, longitudinal axis of the hub blade 30. The hub attachment plate 25 is also attached to the blade attachment member 31. A hub attachment plate hole 26 is located through the hub attachment plate 25 for this purpose. The blade attachment member 31 is located through the hub attachment plate hole 26 and welded to the hub attachment plate 25.

The hub attachment plate 25 is connected to the hub 20 via the end wall 21 A of the boss 21 and the side wall 22A of the flange 22. That is, edges of the hub attachment plate 25 extend and are welded to the end wall 21A of the boss 21 and the side wall 22A of the flange 22. The hub attachment plate 25 forms an angle of substantially 45 degrees with respect to the end wall 21A of the boss 22. The hub attachment plate 25 also forms an angle of substantially 45 degrees with respect to the side wall 22A of the flange 22.

Similar to the hub blades 30, the cowl blades 40 are arcuate in shape and are able to be driven by the wind. The cowl blades 40 extend between and are joined to both the first cowl 50 and the second cowl 60 as shown in FIG. 4. The cowl blades 40 are the substantially the same length and orientation as the hub blades 30. Further, the cowl blades 40 are substantially in alignment with the hub blades 30.

Both the first cowl 50 and the second cowl 60 are iri the form of a frusto conical continuous ring of metal with the first cowl 50 being smaller than the second cowl 60. First cowl 50 and the second cowl 60 are an angle of approximately 12 degrees with respect to a central axis of rotation of the hub 20 as shown in FIG. 5.

In use, it is believed that a cowl with an angle of 12 degrees will be aligned parallel to the local wind streamlines, so that its interference in the wind flow field is minimised. It is believed that this minimises turbulence, drag, and noise.

It should be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit or scope of the invention.