Patent Application
20120251322
A rotating fluid conduit utilized such as a propeller or turbine, characterized by a rotating annulus, formed by a rotating inner hub and a rotating outer shell. Rotating internal vanes are arranged within the annulus and are affixed to the inner hub and the outer shell. The annulus area varies from the inlet to the outlet and the angle of the vanes within the annulus varies to control the tangential velocity and axial velocity of the fluid stream.
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The present invention is in the field of endeavors related to dynamics of fluid motion more particularly to rotating fluid conduits such as turbine rotors and propellers designed using computer simulation.
There is a focus on the design of ships and ferries that can achieve 70 knot plus speeds. But current propeller technology cannot produce a propeller to supply the required thrust at these speeds.
Conventional propellers operate in “sucking mode” relying on negative pressure at the forward portion of the propeller. The flow of fluid “sucked” into the forward face, of the open type conventional propeller, is then mostly ejected radially from the propeller. The faster the forward speed of the vessel the less negative “sucking” force is generated at the forward face of the propeller. The revolutions per minute (RPM) of the propeller must be increased in order to increase the flow, to compensate for the reduction in negative pressure at the forward face of the propeller. But, the higher the RPM of the propeller, the more fluid is ejected radially until eventually cavitation occurs at the blade faces and the propeller “crashes”.
The prior art has disclosed means to reduce the radial velocity of the fluid but reducing the radial velocity reduces flow and/or reduces the effective area of the effective forward face of the propeller and reduces performance or increases cavitation.
Jet pump propelled boats do not exhibit the same problems as propellers of the prior art because jet type propulsion relies on positive thrust generated by the fluid being ejected rearward at a greater velocity than the forward speed of the vessel. The fluid flow and the area of the outlet nozzle determine the speed of the fluid exiting at the outlet.
A diligent search revealed no prior references disclosing controlling the annulus area of a rotating propeller to effect an increased rearward velocity of the fluid. While varying the area of fluid exit is common to non-rotating nozzles, this class would not apply to the rotating annulus of a propeller or turbine.
The Propulsion Committee, Final Report and Recommendations to the 25th ITTC, 2008, available on the Internet; is hereby incorporated by reference.
For over 100 years, the prior art has never completely understood the dynamics of a propeller. Attempts at predicting the performance of a propeller have been attempted by the use of numerical methods because the prior art had deemed an exact analytical solution too complicated. But, numerical methods are an approximation at best and then only within a narrow range of values. Numerical methods have proved ineffective in the design predictability of conventional open propellers outside the known range of values. i.e., forward speed, shaft revolutions per minute (RPM).
Manatees, seals, porpoises, and whales are just a few of the water creatures that have been devastated by the exposed cantilevered blades of conventional marine propellers.
There exists, therefore, a need for a propeller that has improved performance, that can be analytically calculated, and is safer for marine life.
The working fluid in an axial flow turbine flow parallel to the axis of rotation. A conventional radial centrifugal turbine is a turbine in which the flow of the working fluid is radial to the shaft. While radial centrifugal turbines are efficient, the intricate casing configuration makes the cost of large conventional radial centrifugal turbines prohibitive. Since the outer housing of the prior art is stationary, viscous drag caused by the tangential velocity of the fluid relative to the non rotating outer housing robs power output and reduces efficiency.
Boyce, M. P., Gas Turbine Engineering Handbook Second Edition, Butterworth-Hienemann, 2003; is incorporated by reference.
Existing design turbine rotors involves collecting data from tests wherein: several blades are placed in a row, called a “cascade” and exposed to a fluid stream, in an attempt to simulate a compressor rotating fluid conduit. This method tests the current cascade but is inaccurate when attempts are made to extrapolate the test data to other turbine configurations.
There exists, therefore, a need for a power generating turbine that has predictable and improved performance, lower viscous drag, and that can provide reaction, impulse, and axially directed centrifugal extraction of energy.
The present invention, “rotating fluid conduit”, is unique and novel in that it is characterized by a rotating annulus formed by a rotating inner hub and a rotating outer shell with rotating internal vanes, arranged within the annulus and affixed to the inner hub and the outer shell. The annulus area varies from the inlet to the outlet and the angle of the vanes within the annulus also varies to effect a change in the tangential and axial velocity of the fluid stream and thereby provide a corresponding change in the axially directed and tangentially directed energy of a fluid.
When the rotating fluid conduit is embodied as a propeller, the diameter of the exit of the hub is larger than the diameter of the entry of the hub therefore the annular area located at the outlet is less than the annular area located at the inlet. This reduction in annular area from the inlet to the outlet causes the speed of the fluid, exiting the outlet to increase. Increasing the speed, of the fluid at the outlet, results in a positive axial thrusting force being exerted upon the propeller.
Contrary to the prior art, at design speed the present invention can have 100% positive thrust and 0% negative pressure at the forward face. Cavitation cannot exist in the absence of negative pressure.
The present invention has an inherent safety feature given that the outside diameter of the rotating vanes are not exposed. Therefore marine life is not exposed to “tangential slicing”. The rotating outer shell can also be axially extended forward of the “leading edge” of the vanes and/or behind the “trailing edge” to give added protection from accidental “reach in” of hands, fins, feet, flippers, and other biological appendages.
When the present invention is embodied as a power generating turbine, the rotating fluid conduit can provide extraction of fluid energy using the difference in centrifugal force from the fluid flow at the inlet to the fluid flow at the outlet. Reduction of the centrifugal radius at the outlet annulus from that of the centrifugal radius at the inlet annulus provides a change in centrifugal force from the inlet to the outlet that causes rotational energy to be transmitted to the rotating fluid conduit. Contrary to the prior art the outer shell rotates as part of the rotating fluid conduit so therefore there is no viscous drag caused by the tangential velocity of the fluid.
By varying the arrangement of the vanes at the inlet, the present invention can also concurrently provide impulse extraction of fluid energy from the fluid striking the forward face of the vanes. The present invention can also simultaneously provide extraction of fluid energy via reaction by varying the design of the annulus and the vanes so that tangential velocity of the fluid, at the outlet, will impart rotational energy to the rotating fluid conduit.
Since the radial velocity of the fluid flow does not exist in the present invention, the axial and tangential components of the fluid can be calculated to exact analytical solution rather than approximated by the numerical methods of the prior art. The resulting three dimensional (3D) design of the annulus areas and the angle of the vanes results in predictable improved performance and greater efficiency over that of the prior art. As examples: A marine or aircraft propeller can be designed to maximize the axial component of the fluid flow, at the outlet, for maximum thrust. A power generating turbine can alternatively be designed with the tangential velocity (reaction) and the annular radius (centrifugal) at the outlet of the working fluid adjusted to produced maximum rotational power output.
These together with other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated alternate embodiments of the invention.
For the embodiments depicted in
Detailed descriptions of two possible embodiments of the invention, marine propeller and power generating turbine, are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.
A more complete understanding of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: analogous parts are identified by like reference numerals as follows:
Similar to propellers, pump impellers, compressors, fans, and power generating turbines the present invention can be made in various sizes and configurations including but not exclusively with any number of vanes, varying diameters of the rotating outer shell and varying diameters of the inner hub. It should be recognized that the present invention is not limited to the use in propellers and generating turbines having the specific designs which are herein described for purposes of example.
Referring jointly to
The rotating outer shell 104 is attached to the vanes 105 and rotates along with the hub 103 and the vanes typical of 105.
Hub 103 is depicted, in this example, with an axially directed shaft 106 for the purpose of transmitting rotational energy to the propeller 100. Alternatively, rotational energy to the propeller 100 could be transmitted via the rotating outer shell.
The vanes typical of 105 are pitched relative to the axis of rotation 199 of the propeller 100 to cause a flow of fluid 101a into the inlet 101 and a flow of fluid 102b from the outlet 102, when the propeller 100 is rotated.
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This reduction in annular area from inlet 101 to outlet 102 causes the speed of the fluid 102b, exiting the outlet 102, to increase. Increasing the speed of the fluid 102b at the outlet 102 results in an axial thrusting force 110 being exerted upon the propeller 100.
The design of the rotating outer shell, the hub, and the vanes are analytically calculated for the for the desired performance of the rotating fluid conduit.
In the example depicted in
Referring jointly to
The rotating outer shell 104 is attached to the vanes 105 and rotates, as one, with the hub 103 and the vanes typical of 105.
Hub 103 is depicted, in this example, with an axially directed shaft 106 for the purpose of transmitting rotational energy from the power generating turbine 100 to an energy consuming device such as a electric generator. Alternatively, rotational energy from the power generating turbine 100 could be transmitted via the rotating outer shell.
The vanes typical of 105 are pitched relative to the axis of rotation 199 of the power generating turbine 100. The shaft is caused to rotate by the flow of fluid 101a into the inlet 101 and the flow of fluid 102b from the outlet 102.
As depicted in
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This reduction in centrifugal force exerted by the fluid flow 102b at the outlet 102 annulus from the centrifugal force exerted by the fluid flow 101a at the inlet 101 annulus causes rotational energy to be transmitted to the power generating turbine 100 in the direction of rotation 199. In this example the rotational energy imparted to the power generating turbine 100 is transmitted to the shaft 106 but rotational energy from the power generating turbine 100 could also be transmitted via the rotating outer shell.
The design of the rotating outer shell, the hub, and the vanes are analytically and synergistically calculated for the for the desired performance of the rotating fluid conduit.
Another computer program can then generate a three dimensional (3D) model based on the analytical solution to the desired performance. This computer generated three dimensional (3D) model can then be used to generate a tool path designed for computer aided manufacturing of the elements depicted in FIGS. 1,2,3,4,5,6,7, and 8.
The elements depicted in FIGS. 1,2,3,4,5,6,7, and 8, when configured for lower density fluids, such as air, can be constructed of materials typically used in the relevant industry (e.g., aerospace, helicopter, wind generating turbines, aircraft). These materials include but are not limited to, metals, plastics, fabrics, and/or composite materials.
The elements depicted in FIGS. 1,2,3,4,5,6,7, and 8, when configured for medium to higher density fluids, such as water, can be constructed of materials typically used in the relevant industry (e.g., marine propellers, gas turbines, steam turbines) by techniques including machine cutting, fabrication, or casting from metal or plastic or a combination of materials.
While the invention has been described in connection with the embodiments illustrated above, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention. It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims and their legal equivalents. While several forms of the invention have been shown and described in the above teachings, other forms will now be apparent to those skilled in the art. Therefore, it will be understood that the embodiments shown in the drawings and described above are merely for illustrative purposes, and are not intended to limit the scope of the invention which is defined by the claims which follow.
This application claims priority from applicant's U.S. Provisional Patent Application Ser. No. 61/465,954, filed on Mar. 28, 2011.
| Number | Date | Country | |
|---|---|---|---|
| 61465954 | Mar 2011 | US |
