Patent Application
20050271508
Conventional turbines typically have solid, rigid structures to form blades for the turbines. Such rigid blades are able to rotate at high speeds under normal conditions. However, when it is desired that the turbine blade rotates in the same direction regardless of the flow direction, symmetrical blades are often desired. For example, a Wave Energy Conversion (WEC) system can require that the turbine blade rotates in the same direction regardless of the flow direction. Such a system can use a Wells Turbine. However, the Wells Turbine has symmetrical, rigid blades and relatively low efficiency. Wells turbines with variable pitch, rigid blades to improve efficiency are being designed and tested but the variable pitch technology is very different from the flexible turbine blade described in the present application.
The present application describes systems, methods and techniques for a flexible blade turbine system.
One aspect of the present application relates to a method for increasing efficiency of a symmetrical blade comprising providing a rigid portion of the symmetrical blade and providing a flexible portion of the symmetrical blade. The rigid portion of the symmetrical blade can be connected to the flexible portion of the symmetrical blade. The flexible portion of the symmetrical blade can be adapted to bend with a flow across the symmetrical blade. The symmetrical blade can be adapted to rotate in one direction for a bi-directional flow across the symmetrical blade. The symmetrical blade can be adapted for at least one of a Wave Energy Conversion (WEC) system, a fan, an exhaust system, a blowing system, and a suction system. The rigid portion of the symmetrical blade can be fixed to an axis perpendicular to a direction of flow. The symmetrical blade can be rotated in a direction orthogonal to the direction of flow and orthogonal to the bending of the symmetrical blade. The rigid portion may comprise metal, wood, and plastic, wherein the flexible portion may comprise plastic and rubber. The symmetrical blade may comprise a pear-shaped blade or a rectangular-shaped blade.
In another aspect, the present application may describe a system for increasing the efficiency of a turbine with a symmetrical blade. The system may comprise a rigid portion of the symmetrical blade and a flexible portion of the symmetrical blade. The flexible portion of the symmetrical blade may connect to the rigid portion of the symmetrical blade, wherein the flexible portion is adapted to bend in a direction of flow across the symmetrical blade. The geometry of the symmetrical blade can vary to reduce an amount of loss from an entirely rigid, symmetrical blade. The geometry of the symmetrical blade can also vary to increase the efficiency of the symmetrical blade over an entirely rigid symmetrical blade. The symmetrical blade can be adapted to rotate in a single direction for a bi-directional flow across the symmetrical blade. The symmetrical blade may comprise plastic and metal.
Details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages may be apparent from the description, drawings, and claims.
These and other aspects will now be described in detail with reference to the following drawings.
Like reference symbols in the various drawings indicate like elements.
The systems and techniques described here relate to a blade for turbine or fan systems. In particular, the system described herein relates to a blade that rotates in the same direction regardless of a flow direction (e.g., bi-directional flow). The disclosed system may provide higher efficiencies than conventional symmetric blades responding to bi-directional flows.
A symmetrical blade can allow the blade to rotate in one direction regardless of the direction of a flow across the blade. Such a flow may be referred to as a bi-directional flow. In conventional systems, such as a Wave Energy Conversion (WEC) system, the symmetry of the blade can lead to lower efficiencies than a conventional non-symmetrical turbine blade. A typical turbine that can be used for a WEC system may be a Wells Turbine. A Wells Turbine has rigid, symmetrical blades. The system described herein can provide a higher efficiency than the efficiency of a Wells Turbine.
In one aspect, the blade 105 may be partially rigid and partially flexible. The blade 105 can have firmly mounted part 135 of length L 125 on the X axis. The blade 105 may also have a length N 102 on the X axis towards the trailing edge 140 (e.g., tail part) that allows a flapping movement 115. The bending/flapping movement 115 can be in response to a force and a direction of flow. The flexible portion 140 of the blade 105 can bend with the flow direction and give the turbine blade more impulse. The bending of the blade 115 allows the blade 105 to rotate faster than a conventional, rigid Wells turbine blade. The bending of the blade 115 can allow the geometry of the symmetrical blade 105 to vary from a conventional rigid, symmetrical blade. The varying geometry of the symmetrical blade 105 can reduce an amount of loss and increase the efficiency of the symmetrical blade 105 over a conventional rigid, symmetrical blade.
In another aspect, the blade 105 can be entirely rigid. For this aspect, length L 125 is equal to length M 104 and length N 102 is zero. The rigid blade 105 may rotate in a direction of the Z axis 220 without the bending of the blade 115.
In another aspect, the blade 105 can be entirely flexible. For this aspect, length L 125 is zero and length N 102 is equal to length M 104. The blade 105 can bend in response to the flow direction. The entire blade 105 can also rotate around the Z axis 220. In one embodiment, the blade 105 may bend in a y direction 120 and not rotate around the Z axis 220. In another embodiment, the blade may not bend in a Y direction 120 and rotate around the Z axis 220. Under typical operation, the blade 105 can both bend 115 in the y direction 120 and rotate around the Z axis 220. The amount of bending 115 may depend on an intensity of the flow, the flexibility of the blade 105, and the amount of rotation around the Z axis 220.
The entirely flexible blade 105 can bend with the flow direction and give a turbine blade more impulse. The entirely flexible blade 105 has the freedom to move in the X direction and/or the y direction. The entirely flexible blade 105 may rotate faster than a rigid Wells Turbine blade. The flexibility of the symmetrical blade 105 may (1) vary the geometry of the blade 105, (2) reduce the losses of the blade 105 and (3) increase the efficiency of the blade 105 over a rigid, symmetrical blade.
The blade 105 may be constructed out of a material that can allow the blade 105 to have a flexible portion and/or a rigid portion. For example, the blade 105 may have a rigid portion made from materials such as hard plastic, wood, or metal. The blade 105 may have a flexible portion made out of materials such as plastic or rubber. The blade 105 may be constructed with a hard plastic material for a rigid portion 135 and a flexible plastic material for the flexible portion 140. The rigid portion 135 and flexible portion 140 may be one piece of material or two or more attached pieces of material.
The blade 105 may operate in other systems other than WEC systems. For example, the blade 105 may operate in suction systems and blowing systems. The blade 105 may also operate in exhaust systems and fans.
In another aspect, the blade 105 may be have a different shape other than what is shown in
In another aspect, the blade 105 may have a flexible portion 137 of length N 102 positioned between a rigid portion 135 of length L 125 fixed to the X axis 110 and a rigid portion 440 of length p 128 that is not fixed to the X axis 110 as shown in
In another aspect, the rigid portion 135 (
The direction of flow, the bending of the blade, and the rotation of the blade may be in other directions, axes, or combinations of axes other than what is shown in
Other embodiments may be within the scope of the following claims.
