WO2010135197A1

WO2010135197A1 - Fluid flow energy harvester surface modifications

Info

Publication number: WO2010135197A1
Application number: PCT/US2010/034968
Authority: WO
Inventors: Joel S. Douglas; William T. Guevremont; Paul Richard Johnson; Armanda E. Ziegler
Original assignee: Egen Llc
Priority date: 2009-05-21
Filing date: 2010-05-14
Publication date: 2010-11-25

Abstract

An improved Magnus effect energy harvester device, intended to harvest energy from slow-moving fluids and gases by transducing the Magnus side forces into a desired form of energy. In this improvement, the surfaces of rotating cylinders are modified to induce a turbulent boundary layer about the cylinder in order to reduce drag of the fluid on the driving cylinder, increase the lift produced, and increase the efficiency of the harvester. These surface modifications may be formed on the surface, dimpled into the surface, or attached to the surface of the cylinder. Alterations may be arranged in any pattern or randomly. Alterations to the surface will be between 0.001% and 10% of the diameter of the Magnus cylinder. There will be at least one alteration on each Magnus cylinder.

Description

FLUID FLOW ENERGY HARVESTER SURFACE MODIFICATIONS CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of U.S. Provisional Patent Application No. 61/216,749 filed May 21, 2009, the contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

This invention relates to a device for harvesting energy and more specifically to an energy harvester that extracts energy from fluid flow by exploiting the lift created by the flow as it passes a rotating cylinder. The device can be used with fluid flow, hydro-pneumatic, hydro, wind, or wave power systems.

DESCRIPTION OF THE RELATED ART

Hydropower systems are used for generating power from the tidal or current motion of water in oceans, bays, and rivers. Typically, such systems require high water head and high flow conditions. Systems that require both high water head and high flow conditions limit the suitable sites for implementing fluid flow energy harvesters. Conventional hydro turbine technology, which involves positioning a powerhouse in a dam body with turbines located below the lowest water level, has been applied at mountain river and waterfall sites where a large water head can be developed. Consequently, powerhouses using hydro turbines are generally installed in large and complicated dam structures capable of withstanding the enormous water pressures generated. On the other hand, the hydro energy potential of thousands of rivers, streams, and canals remain untapped because hydro turbines, as an economical and practical matter, do not operate effectively with a low water head: in other words, when water level differences are about three meters or less. Such conventional hydro turbines need significant water depth for installation and cost-efficient operation. Systems have also been developed to generate power using lower water head. These systems are described in U.S. Pat. Nos. 4,717,832, 5,074,710, and 5,222,833, the disclosures of which are incorporated herein by reference.

Systems for utilizing tidal motion and current flow of oceans and rivers are also known. Such systems usually require a dam or other physical structure that separates one part of a water body from another part. A difference in water levels is thereby created which provides a pressure differential useful for driving mechanical devices such as hydro turbine generators.

Also, axial-flow turbine type devices deriving power from liquid flow in tidal runs and streambeds are known. Such devices are disclosed in U.S. Pat. No. 3,980,894 to P. Vary et al., U.S. Pat. No. 3,986,787 to W. J. Mouton, Jr., U.S. Pat. No. 4,384,212 to J. M. Lapeyre, U.S. Pat. No. 4,412,417 to D. Dementhon, and U.S. Pat. No. 4,443,708 to J. M. Lapeyre.

Pivotal flow-modifying means is shown in the above Mouton, Jr. patent in a multiple unit embodiment.

U.S. Pat. No. 4,465,941 to E. M. Wilson discloses a water-wheel type device for the purpose of flow control pivotal valves or deflectors.

Additionally, various Magnus effect generating systems have been envisioned. The Magnus effect was first publicized by Professor G. Magnus in 1853. The Magnus effect is a physical phenomenon in which a spinning object creates a current of rotating fluid about itself. As the current passes over the object, the separation of the turbulent boundary layer of flow is delayed on the side of the object that moves in the direction of the fluid flow and is advanced on the side of the object that moves counter to the direction of the fluid flow. Thus, pressure is exerted in the direction of the side of the object that moves in the same direction of the fluid flow to provide movement substantially perpendicular to the direction of fluid flow. Briefly stated, when a rotating cylinder encounters a fluid flow at an angle to its rotational axis, a lifting force (lift) is created perpendicular to the flow direction. If a rotating cylinder is mounted on a vertical axis, the lift is developed at right angles to the direction of water flowing past the cylinder, left or right depending upon the direction of rotation.

The use of the Magnus effect as a windmill was disclosed in the 1926 translation of Anton Flettner, "The Story of the Cylinder," published by F. O. Willhofft, New York, N. Y. A cylinder can produce ten times as much lift force as an air cylinder for equal projected areas and wind speeds. The phenomenon is also used to describe, among other things, the curved pitches of baseball and the shooting of airplane guns transversely to the airplane's path of travel.

Various patents disclose the use of the Magnus effect for airplane lift, steering a boat, and for assisting in submarine steering.

The Magnus effect is utilized in U.S. Pat. No. 4,446,379 to Borg et al., which has

Magnus cylinders mounted for rotation at right angles to shafts that are revolved about a generally vertical axis. The shafts are free to rotate 180 degrees. The Magnus cylinders are continuously rotated in the same angular direction. At one position of revolution of the shafts, the cylinders rotate on an axis generally parallel to the axis of revolution of the shafts. When the apparatus is immersed in a fluid flow (gaseous or liquid) a torque of rotation is developed when the shafts are aligned with the fluid flow, and this torque of rotation is reduced as the shaft approaches a position transverse to the fluid flow. As the shafts pass this transverse position, a torque is developed by the rotating cylinder that rotates the shafts 180 degrees at which point the formerly downwardly depending cylinder is now upright and the formerly upright cylinder is now downwardly depending on its shaft. The device was designed to utilize two or more shafts to which cylinders are attached, and there is continuous production of torque about the axis of revolution of the shafts. The complexity of this device makes it a difficult device to build or operate. If the Magnus effect is to be used to generate power, a simpler device is needed.

U.S. Pat. No. 4,582,013 to Holland describes a self-adjusting wind power machine that uses a cylinder.

U.S. Pat. No. 7,504,740 to Murakami, et al. which describes a Magnus type wind power generator includes a horizontal rotary shaft for transmitting torque to a power generating mechanism. Rotary columns are disposed radially off the horizontal rotary shaft. Driving motors rotate the respective rotary columns around the axes thereof. The relative action between rotation of each rotary column and wind produces Magnus lift, which rotates the horizontal rotary shaft so as to drive the power generating mechanism. An air flow device is installed for producing air flow on the outer peripheral surfaces of the rotary columns so as to increase the Magnus lift.

All the above systems suffer from similar problems in that they do not generate enough power to be economical when compared to the input power required to drive the cylinders.

Co pending U.S. Patent application 20090058091 MAGNUS FORCE FLUID FLOW ENERGY HARVESTER the disclosure is incorporated in its entirety: describes an energy harvester capable of providing motion from fluid flow, including a Magnus cylinder defined as a cylinder driven by a motor causing the cylinder to rotate so that lift is created by the fluid flowing past the cylinder. A channel or system may be provided to direct the fluid flow to the cylinder. The rotating cylinder configuration is integrated into a mechanical device that is designed to transfer the lift into a mechanical motion to drive a generator. The mechanical motion due to the created lift is reversed by using a stalling mechanism and counter balanced mechanism. This creates a bi-directional motion that can be captured and used to drive a generator. The device can be utilized in either pneumatic or hydraulic environments. A modification of the energy harvester can be configured to utilize the electricity generated to produce hydrogen for use in fuel cells or for combustion.

Pneumatically driven systems using turbine blades have also been developed. However, these systems normally use blades that rotate at high speeds. These rotating blades are problematic as any sizable foreign object encountered by the system can cause damage, thereby compromising the structural integrity of the system. When the system utilizes the flow of air such as in the use of turbine blade aircraft, bird strikes can cause significant damage to the rotating blades, as can stones or other debris inadvertently or intentionally injected into the rotating blades. When the system is a water system, the injection of aquatic plants and animals as well as debris frequently found in waterways (e.g., chunks of wood) can also cause damage.

The majority of the systems envisioned by the aforementioned technologies utilize rotating blades that are noisy, detrimental to both flora and fauna, and require dams that interfere with the motion of the flowing water, cause considerable ecosystem damage and create greenhouse gases from the decay of stagnating flora. Additionally, the systems that are utilized in these applications significantly obstruct sunlight, which has a further detrimental effect on aquatic plant life. These approaches are normally resisted by the affected communities due to the harm caused to flora and fauna and the damming of the body of water, which negatively affects community activities. Damming and rerouting water flow can also cause significant upstream destruction of wildlife habitats and developed areas. Low head and low flow hydraulic conditions are prevalent throughout the world. The

US Department of Energy (DOE) has studied the amount of low head water sources available in the United States and has published the result of that study in DOE report DOE-ID-11263 entitled Feasibility Assessment of the Water Energy Resources of the United States for New Low Power and Small Hydro Classes of Hydroelectric Plants. The difficulty described therein is that there are no simple and effective methods to harness the energy from low head water sources to create power. Table 1 from that report provides a summary of hydroelectric energy in the United States and shows that with regard to the low head/high power and all low power sources including unconventional and micro hydro sources, there is approximately 47,000 MW of power available for harvesting. Effectively harvesting this capacity would more than double the power currently generated by hydro sources in the United States alone.

Table 1

However, despite the technological efforts described previously, there is no known system capable of generating electricity from low head/high power and low power sources such as tidal and/or river flow while being capable of continuous generation under changing flow conditions.

Given the increasing demand for industrial electricity in view of the issues related to the current state of the art of fluid flow energy harvesters, a need exists for a system that does not harm flora or fauna and can be introduced into the environment without interfering with the natural water flow or blocking the majority of the sunlight to the bottom of the body of water. A need also exists for an environmentally friendly, quiet, efficient, and simple energy harvester that can operate in low head and low flow conditions.

BRIEF SUMMARY OF THE INVENTION As used herein, the term "hydro application" and "hydraulic" are used to describe the use of the energy harvesting device with regard to liquid, and the term "gas application" and "pneumatic" used to describe the use of the energy harvesting device with regard to gas (e.g., air). As used herein, the term "lift" refers to a force that is perpendicular to a direction of fluid flow herein called the Magnus side force.

As used herein, the term "electrical grid" refers to any system used to utilize or transport electrical current. The present invention provides an energy harvesting device (or energy harvester) capable of generating energy from low power hydraulic or pneumatic flows using lift generated by the Magnus effect by taking advantage of the availability of sources of fluid flowing under low head pressure and/or flows of velocities of 0.25 feet per second or greater. The energy harvester comprises inflow and outflow fluid channels, an energy harvester chamber, and a revolving cylinder with fins, tubercles or dimples on it, which is typically mounted in a horizontal configuration and transversely to the direction of fluid flow. These fins, tubercles or dimples on the cylinder increase the lift coefficient and decrease the drag such that the power that can be generated from the Magnus rotor is more than the power required to rotate the cylinder. The system is also constructed with an inflow channel is provided with diverters and baffles to direct the flow of fluid to the cylinder while the surrounding channel creates a boundary condition which focuses the fluid flow so that there are only minimal losses in fluid flow interacting with the Magnus cylinder.

(Note that a dimple is an indentation or crater measured from the nominal diameter of the cylinder. It is usually spherical in shape but it can be formed so that is a hollow parabolic solid of revolution shape formed into the surface of the cylinder. By contrast, a tubercule is a feature that is structured so that its outermost dimension is greater than the nominal diameter of the cylinder. Therefore, a tubercule can be any small, usually solid, nodule or prominence such as a rounded mass attached to or formed as part of the cylinder or surface. Tubercules can be either spherical in shape, or alternatively can be formed so that is a parabolic solid-of- revolution shape or bump on the surface of a cylinder or other surface.)

The lift or Magnus side force can be transferred into a mechanical system; for example, it can be transferred to a generator via a drive shaft or a similar mechanism. This lift can also be harnessed to drive a reciprocating device.

For gas applications, the energy harvester applications are under ultra low head pressure fluid flow, and the energy harvester can readily deliver significant lift, allowing the system to drive a conventional industrial generator. The result is that the energy harvester of the present invention achieves efficiencies higher than energy harvesters of the prior art. For hydro applications, the energy harvester can operate under ultra low head flow or any current of 0.25 foot per second or greater, which is less than needed for prior art energy harvesters. As the energy harvester uses a pivoting hydro cylinder or air cylinder, it will be highly scalable since the energy required to develop lift is small and the lift developed is very large and can be focused.

In the case of pneumatic energy conversion, the channel forces the air to be directed at the air cylinder and delivers it so maximum lift is created. The energy captured in the flowing air is then converted to mechanical energy. Connection of the energy harvester to an electric generator allows for the generation of electrical energy. No additional gearing to increase the speed of the air energy harvester to the generator's speed is required.

In a hydro application embodiment, the energy harvester can be mounted in a self- floating configuration such as a vessel or platform located in a current of 0.25 feet per second or greater, such as in a tidal channel. In such an embodiment, the energy harvester is located just below the surface of the water, where the current velocity is greatest, and is retained in that location by virtue of the rise and fall of the vessel with the water. The rotary energy harvester embodiment is uniquely suited for this application. A housing to channel the flow to the energy harvester may be provided if desired, but is not necessary if the current velocity is sufficiently great. The energy harvester is connected to a suitable electric generator, which may be mounted on the vessel in a water tight chamber or which may be remotely located. Since the energy harvester is located in the water, the lift is converted into mechanical energy to drive the generator.

Alternatively, the system can be constructed so that it sits on the bottom of the water channel so as not to obstruct the surface activities.

Alternatively, the flow can be concentrated so that the speed of the fluid passing cylinder is accelerated to increase the lift of the cylinder. Channeling the flow from a larger cross section into a smaller cross section where the cylinder can take advantage of the increased flow speed of the fluid facilitates an increase in the lift of the cylinder.

A novel method of extracting energy by reducing the friction and drag on a Magnus cylinder is shown. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which:

Figure 1 is a cross section representation of a hydro cylinder showing a Microfin Magnus Rotor.

Figure 2 is an isometric representation of a hydro cylinder showing a MicrofinMagnus Rotor.

Figure 3 is a cross section representation of a hydro cylinder showing a dimpled Magnus Rotor.

Figure 4 is an isometric representation of a hydro cylinder showing a dimpled Magnus Rotor. Figure 5 is a cross section of a hydro cylinder showing tubercles on a Magnus Rotor.

Figure 6 is a lengthwise cross-section representation of a hydro cylinder showing a tubercles Magnus rotor.

Figure 7 is a schematic representation of a smooth vs. a Microfin hydro cylinder illustrating the shear planes. Figure 8 is a chart illustrating 2 foot on-axis prototype torque vs. Magnus rotor RPM; comparison of measured torque vs. theoretical torque (Flow Velocity = 2.0 ft/s), (4 Magnus rotors, measured at 4" O.D. x 6.8" long).

Figure 9 is a chart illustrating 2 foot on-axis prototype torque vs. Magnus rotor RPM; comparison of measured torque vs. theoretical torque (Flow Velocity = 2.0 ft/s), (4 Magnus rotors, measured at 4" O.D. x 6.8" long) for the low end of RPMs.

Figure 10 is a schematic showing a tubercle cylinder being applied to a hydraulic energy harvester.

Figure 11 illustrates the effect of dimples on the surface of a golf ball. Figure 12 illustrates the Magnus effect. Figure 13 shows the force application on an on-axis Magnus system

Figure 14 is a side view of a Magnus cylinder device configured as a turbine Figure 15 is an end view of a Magnus cylinder device configured as a turbine DETAILED DESCRIPTION OF THE INVENTION

The driving cylinder for an energy harvester for use in hydraulic flows according to the present invention is shown in Figures 1 through 6. Surface configurations are applied to the driving cylinder of the current invention. The Microfin configuration is shown in Figure 1 (Microfin Configuration Side View) and in Figure 2 (Microfin Configuration Isometric View). As can be seen in Figure 2, the Microfin configuration consists of lengthwise protrusions or ridge 10 around the cylinder's surface 1. The Microfins 10 have a thickness from 0.001% to 10% of cylinder's diameter 5 based on testing performed in a hydraulic flume on various configurations. There is at least one Microfin 10 on the Microfin configuration. The increase in lift force or Magnus side force seen in Figure 8 shows the comparison between measured torque when using 12 small fins, versus the measured torque for the same size rotor with a smooth surface for a fluid flow of 4 feet per second in water. Figure 9 shows the comparison between measured torque when using 12 small fins versus the measured torque for the same size rotor with a smooth surface for a fluid flow of 2 feet per second in water. Testing performed in a hydraulic flume gave the following results found in Table 2 and 3. Table 2 shows the percentage increase in lift at each water velocity as compared to a smooth cylinder of 1.25 inch diameter.

Table 2

Table 3 shows the percentage increase in velocity for a finned cylinder at each water velocity as compared to a smooth cylinder of 1.25 inch diameter. The fin configuration also increased the velocity of the cylinder

Table 3

Dimples are another means of modifying the surface of a rotating cylinder. The dimples form uniform bumps on the surface of the cylinder. The dimple configuration shown in Figure 3 (Dimple Configuration Side View) and in Figure 4 (Dimple Configuration Isometric View) consists of dimples 2 on the surface of the cylinder 1, whose depth 14 and diameter 15 range from 0.001% to 10% of the cylinder's diameter 5 based on testing performed in a hydraulic flume on various configurations. There is at least one dimple on the dimple configuration. Testing performed in a hydraulic flume gave the following results found in Table 4 and 5. The percentage increase in lift or Magnus side force at each water velocity for a dimpled cylinder with 1308 dimples as compared to a smooth cylinder of 1.25 inch diameter is shown in Table 4. Table 5 shows the percentage increase in velocity at each water velocity for a dimpled cylinder with 1308 dimples as compared to a smooth cylinder of 1.25 inch diameter.

Table 4

Table 5

The concept of tubercles is one derived from the observations of whale fins as discussed in US patent applications 20090074578 and 20060060721 (the disclosures of both are incorporated herein in their entirety). Dimples are another means of modifying the surface of a rotating cylinder. The tubercles form uniform bumps on the surface of the cylinder. The tubercles configuration features bumps or pimples on the surface of the cylinder 1 Figure 5 Tubercle Configuration Side View and Figure 6 (Tubercle Configuration Section) consists of tubercles 24 on the surface of the cylinder 1 , whose depth 25 and diameter 20 range from 0.001% to 10% of the cylinder's diameter 5 based on testing performed in a hydraulic flume on various configurations. There is at least one tubercle on the tubercles configuration. Testing performed in a hydraulic flume gave the following results found in Table 6 and 7. Table 7 shows the percentage increase in lift or Magnus side force for a cylinder with 330 tubercles at each water velocity as compared to a smooth cylinder of 1.25 inch diameter. Table 6 shows the percentage increase in velocity for a cylinder with 330 tubercles at each water velocity as compared to a smooth cylinder of 1.25 inch diameter.

The tubercles perform similarly to the dimples in that they transfer the shearing plane as much as possible to a water- water shearing interface from a water-cylinder shearing interface.

Table 6

Table 7

It is theorized that these three surface configurations shown in Figures 1, 2, 3, 4, 5 and 6 create better adhesion of the boundary layer to the surface of the cylinder through the creation of turbulent flow, reducing parasitic drag and improving performance. They also transfer the shearing force from the fluid boundary to the cylinder to the reduced fluid boundary and cylinder surface as shown in and Figure 7.

The Microfins, dimples and tubercles can be arranged in varying densities and patterns on the cylinder's surface. They can be arranged in a uniform geometric pattern or they can be arranged in a random pattern. The reduced shearing force required to rotate the cylinder 2005 with lengthwise protrusions or ridges vs. the smooth cylinder 2010 is shown in Figure. 7. For the cylinder 2005 the sum of the Force 1001, which is the force created by the adhesion of the fluid to the cylinder protrusion, and the force 1005, which is the force between the fluid to fluid interface between the protrusions, is less than the force 1010 for cylinder 2005, force 1010 is the force created by the adhesion of the fluid to a smooth cylinder because the adhesion forces are greater for the water to wetted surface interface as compared to the water to water shearing force. Since the wetted area is greater on the smooth cylinder 2010 than the finned cylinder 2005, the result is a reduction in the torque required to rotate the cylinder and therefore a decrease in the energy required to rotate the cylinder, which increases the power output of the system by reducing the parasitic use of energy to rotate the Magnus cylinder.

The Microfins reduce the drag much the same way as the lacing will reduce the drag on a baseball. The dimples as shown in Figs. 3 and 4 and the Tubercle Figure 5 and 6 act very much in the same way as those of a golf ball in that they increase the turbulence of the boundary layer and therefore increase the driving distance as shown in Figure 11 which shows the effect of dimples on a golf ball that is a sphere. From Figure 11 the smooth sphere 2000 forms the laminar boundary layer 2010 and separation 2005 so as to produces a thick wake 2003. The Dimpled sphere 2001 forms the laminar boundary layer 2020 and separation 2030 form transition 2015 and a turbulent boundary layer 2025 so as to produce a thin wake 2004. The dimples also decrease the shearing surface of the cylinder and transfer the shear to the water layer surrounding the cylinder.

The reduction in drag for the cylinder when the surface is modified as shown in Figures 1,2, 3, 4, 5, and 6 was unexpected because the theory was that by changing the surface we would disrupt the lift. What we found was quite different and resembled much of what has been accomplished in golf ball technology. The difference is that golf ball technology is focused on making the ball go further while the focus of our surface modifications is to increase the resulting net force, straighten it out so that it becomes perpendicular to the fluid flow and increases the speed of the cylinder by reducing the drag. By modifying these three resultants we increase the power output for a Magnus cylinder turbine and improves the machine efficiency. These improvements make the utilization of a Magnus cylinder energy harvester more efficient. An additional advantage is that a Magnus cylinder does not have the tip speed or the vortex shedding issues of alternative approaches, such as turbine blades. Therefore the Magnus cylinder device becomes more desirable as a solution to extract energy from run of the river fluid flow. Looking at Figures 8 and 9 which provides data of testing the Microfins on a device shown in Figure 14 and 15. It is clear that the Microfin configuration produced more torque than the classical Magnus lift force calculations can justify. These calculations are explained at NASA's web site http://www.grc. nasa.gov/WWW/K-12/airplane/cyl.html (Lift of Rotating Cylinder) the disclosure is incorporated in its entirety. This increase in torque when evaluated can only be attributed to the increase in life force or Magnus side force. This is the direct result of the Microfin modification.

The resulting cylinders can be mounted to a structure such as the one shown in Figure 10, where the energy harvester is in communication with a fluid flow (or gas flow). The energy harvester comprises inflow fluid channel walls 4, energy harvester channel side walls 8 that receive a flow 90 from the inflow channel walls 4, outflow fluid channel walls 6 that direct the flow from the channel side walls and a cylinder 5 mounted between the channel side walls. The energy harvester may also comprise side walls and a bottom chamber wall. The fluid flow path defined by an inflow fluid channel, an outflow fluid channel, and an energy harvester chamber disposed between said inflow fluid channel and said outflow fluid channel. The walls can also be curved either in the side or bottom walls in this configuration and have opposite elevations in the plane parallel to the fluid flow path. This acts as a concentrator for the fluid flow by channeling a greater volume of fluid to the energy harvester thereby increasing the speed of the fluid that will increase the lift generated by the cylinder. This intensification can be used in any of the embodiments envisioned by the present invention.

The cylinders are mounted inside a channel 91 formed by the opposed channel side walls, and optional bottom chamber wall, the inflow fluid channel walls, and the outflow fluid channel walls. This channel directs the flow through the energy harvester. The cylinder(s) is (are) oriented transversely to the flow through the channel and mounted for rotation, for example, via bearings in the cylinder supports.

The cylinder(s) is (are) rotated by a drive mechanism such as a motor. The lift is generated via the Magnus effect when the flow is concentrated through the channel and the cylinder(s) is (are) rotated in the correct direction, forcing the mechanism to reciprocate and causing the connecting rod to move up and down. This concentrating of fluid in the channel accelerates the flow by funneling the fluid towards the cylinder(s), thereby increasing the lift.

Alternatively the Magnus cylinders described in this invention can be used in an energy harvester 1 for use in fluid flows according to the present invention as shown in FIGS. 14 and 15 and mounted to a structure where the energy harvester is in communication with a fluid flow 90. This energy harvester 1 can be configured to sit on a bottom of a water course or fluid flow channel, or can be positioned inside of a fluid flow channel such as in a pipe. The energy harvester 1 comprises inflow fluid channel walls 4, 5, 6 and 7, energy harvester that inscribes a larger cross sectional area 5000 than cross sectional area 5001 formed by channel side walls 8, 9, 10 and 11 that receive a flow 90 of velocities of 0.25 feet per second or greater from the inflow channel walls 4, 5, 6 and 7. This funneling causes the fluid to flow faster in the cross sectional area 5001 than cross sectional area 5000. A funnel is a structure with a wide, often conical mouth and a narrower stem. A central shaft 40 with Magnus cylinders 200, 201, 210 and 211 mounted between the central shaft 40 and channel sidewalls 8, 9, 10 and 11 is attached to generator 41. The Magnus side force generated by cylinders 200, 201, 210 and 211 cause central shaft 40 to rotate in direction 39 and drive generator 41. Generator 41 is supported by support 591. The wall structures can also be replaced with a tube not shown. The walls 8, 9, 10 and 11 can also be curved either in the side or bottom walls in this configuration and have opposite elevations in the plane parallel to the fluid flow path. The walls 8, 9, 10 and 11 act as a concentrator for the fluid flow by channeling a greater volume of fluid gathered by walls 4,5,6 and 7 to the energy harvester thereby increasing the speed of the fluid that will increase the lift generated by the cylinder. This intensification can be used in any of the embodiments envisioned by the present invention. The resulting power increase when using Microfin technology is shown in the Tables

2, 3, 4, 5, 6 and 7 and Figure 8 and Figure 9.

The advantage of increased torque is that power is directly related to the force developed and the speed at which the cylinder rotates which is converted to watts that a rotating machine can produce. This results in more power being available for conversion to electricity or other means of power storage.

The Magnus effect shown in Figure 12 has been known for a long time. For example missiles and bullets, when spinning around the long axis, always depart from their ballistic paths. The cause of that departure is an additional aerodynamic force in the direction perpendicular to the missile axis and the velocity vector, the so-called Magnus effect. Gustav Magnus carried out early experiments and established the existence of a side force on the rotating cylinders. The direction of the side force was from the cylinder center towards the side where the rotational velocity was in the same direction as the free stream velocity. Figure 12 shows a visualization of the Magnus effect, illustrating the Magnus side force or lift force 200 generated as a result of the pressure differential that develops on opposite sides of the rotating cylinder 195. Lift force 200 is perpendicular to the direction of flow velocity 220 and is directed from the high pressure zone 225 (bottom of cylinder) to low pressure zone 230 (top of cylinder) caused by rotating the cylinder in direction 206. The net force 210 is the resultant of the lift force 200 and the drag force 205. By reducing the drag force 205 the resultant net force 210 is moving so that it acts more closely with the lift force vector that means more power is extracted from the cylinder.

When this lift force or Magnus side force is used to rotate a turbine device the resultant net force 210 drives the turbine about a central point as shown in Figure 13. Net force 210 acts on cylinders 195 and rotates turbine in direction 240.

Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

Claims:

1. An improved Magnus effect energy harvester device, said energy harvester comprising at least one rotating cylinder in a fluid flow channel containing a moving fluid, and an apparatus attached to said at least one rotating cylinder to transform Magnus side forces acting upon said at least one rotating cylinder to a desired form of energy, said improvement comprising:

Altering at least part of the surface of said at least one rotating cylinder so that said surface is not a uniform surface, thereby increasing said Magnus side forces (lift) acting on said at least one cylinder, and decreasing drag caused by the action of the moving fluid on said at least one cylinder, so that power generated from transforming said Magnus side forces to a desired form of energy is greater than the power require to rotate said at least one cylinder.

2. The device of claim 1, wherein said alteration comprises a plurality of dimples on the surface of said at least one cylinder.

3. The device of claim 2, wherein the depth of said plurality of dimples ranges from 0.001% to 10% of said cylinder's diameter.

4. The device of claim 1, wherein said alteration comprises a plurality of tubercles on the surface of said at least one cylinder.

5. The device of claim 4, wherein the diameter of said plurality of tubercles ranges from 0.001% to 10% of said cylinder's diameter.

6. The device of claim 1, wherein said alteration comprises a plurality of lengthwise protrusions or ridges.

7. The device of claim 6, wherein said lengthwise protrusions have a thickness ranging from 0.001% to 10% said cylinder's diameter.

8. The device of claim 1, wherein said alteration comprises fastening a plurality of dimples, tubercles, protrusions or ridges to said surface of said cylinder.

9. The device of claim 1, wherein said alteration comprises making a plurality of dimples, tubercles, protrusions or ridges part of said surface of said cylinder.

10. The device of claim 1, wherein said apparatus to transform said Magnus side forces to a desired form of energy operates by coupling said Magnus side forces to an electric generator, and wherein said desired form of energy is electrical energy.

11. The device of claim 1 , wherein said apparatus to transform said Magnus side forces to a desired form of energy involves placement of said at least one rotating cylinder so that the fluid is constrained and funneled by at least one wall as it passes said energy harvester device, resulting in the speed of the fluid passing the cylinder being accelerated to increase the Magnus side force of the cylinder.

12. The device of claim 1 , wherein said fluid is a liquid or a gas.

13. The device of claim 12, wherein said fluid is water.

14. The device of claim 13, wherein said fluid flow is caused by sources of fluid flowing under low head pressure at a velocity of 0.25 feet per second or greater, said fluid flows being caused by tidal flows, and/or other ultra low head fluid flows.

15. The device of claim 12, wherein said fluid is a gas.