Fluid Engine with Enhanced Efficiency
An engine provides torque by transmitting power in a fluid using optimally positioned lift-to-drag ratio blades with air-foil shape sections. The fluid may be liquid or gas. Various considerations of engine configuration, fluid density, fluid pressure and fluid temperature are design parameters that can be tuned to achieve high performance. The fluid flow created can be used to drive rotary motion of an output axle, for example.
The present application is related to co-pending U.S. patent application (“Co-pending Patent Application”), Ser. No. 10/963,274, entitled “Method and System for Generation of Electrical and Mechanical Power using Sterling Engine Principles,” filed on Oct. 12, 2004, bearing Attorney Docket No. M-15504 US. The Co-pending patent application is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to the energy conversion devices. In particular, the present invention relates to engines which efficiently transmitting mechanical energy into useful work through fluid motion.
2. Discussion of the Related Art
A heat engine operates by converting the heat energy which causes fluid flows between zones of different temperatures into useful work. A typical heat engine uses the heat energy to drive coordinated and reciprocating motion of a set of pistons or rotary motion of a set of turbine blades. The motion of the pistons or blades drives machinery or a generator.
In the prior art, moving parts for the heat engine operation are enclosed in a housing and coupled mechanically (e.g., by an axle) to external parts to drive external machinery.
Wings and airfoils take advantage of their shapes to obtain aerodynamic advantage in their movements in a fluid (e.g., air). There are many wing and airfoil designs available from many sources including on-line UIUC airfoil database and many more modern airfoils.
National Advisory Committee for Aeronautics (NACA) which designed and tested a variety of wing designs and published the results in a systematic set of tables. These results are still valid today which can be used in designing wings for many applications. The tables provide lift and drag coefficients for airfoils based upon the airfoils angle of attack to the fluid that it is flowing through. Using these coefficients lift and drag forces can be calculated using the following equations:
where C1 is the lift coefficient, Cd is the drag coefficient, ρ is the density of the fluid, V is the velocity of the airfoil relative to the fluid, and A is the area of the airfoil. The ratio of the lift to drag (L/D ratio) is used to compare the efficiency of an airfoil or blade design.
The ratio of the lift to the drag (L/D ratio) is used as a measure for the efficiency of lift creation of the airfoil or blade design at a specific angle of attack with specific fluid characteristics.
The minimum input power Pin required to drive a pump which has a discharge of Q, fluid pressure Ppres, and a theoretical pressure head HT is given by: Pin=QPpres=QρgHT. Euler's turbomachine relation can be used to determine the pressure head created from a set of rotating blades; the pressure head is given by:
According to one embodiment of the present invention, an engine provides efficiency by transmitting power in a fluid using optimally positioned lift-to-drag ratio aerodynamic blades to create a torque. The fluid may be liquid or gas. Various considerations of engine configuration, blade location, blade shape, lift-to-drag ratio of blade, blade angle, fluid density, fluid pressure, fluid path, fluid motion and fluid velocity are design parameters that can be tuned to achieve high performance. The fluid flow created can be used to drive rotary motion of an output axle, for example.
The present invention is better understood upon consideration of the detailed description below, in conjunction with the accompanying drawings.
To facilitate cross-referencing among the figures, like elements are assigned like reference numerals.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSA fluid engine is a device that converts fluid energy into mechanical energy. A fluid engine of the present invention operates by utilizing a lift force gain on an aerodynamic blade, from a drag force that resists the working fluid movement through the blade, to create torque for the fluid engine. The lift force on the blade results from the energy loss by the fluid from the drag force. The lift force creates a torque that sets into motion the movable parts of the fluid engine, thereby operating the fluid engine. An aerodynamic blade with a lift-to-drag ratio (L/D ratio) of 10 means the lift force is 10 times the drag force. According to the present invention, the fluid which flows inside fluid engine may be one or more gases or one or more liquids.
The rotational motion of radial blades 106 creates a centrifugal force that drives the fluid radially, such that a flow is created at an optimal “angle of attack” on each of axial blades 108, providing significant amount of torque to rotate separator structure 111. As shown in
During operation, fluid structure 102 provides sufficient fluid pressure to compensate fluid pressure loss due to drag and friction in fluid circulation. Fluid exiting fluid structure 102 may have a rotational velocity (i.e., angular velocity and hence angular momentum) equal to or greater than the rotational velocity of axial blades 108 to maximize the efficiency of fluid engine 100. Output torque at output axle 113 is the sum of the torques generated by axial blades 108. Engine efficiency can be increased by orienting axial blades 108 such that the fluid flow acts on each blade in a preferred angle of attack, so as to utilize their lift-to-drag ratio to maximize the torque created.
Fluid structure 102, which includes blades 106 and an input axle 101, is located in upper portion 104, is designed to drive the working fluid mechanically and radially outward toward peripheral fluid space 131. Fluid structure 102 may function as an impeller, a pump, a compressor, a fan or a blower, depending on the configuration of blade set 106 and the applications of fluid engine 100. In one embodiment, fluid structure 102 may have adjustable blades or blade configurations such that blade set 106 provides energy for the working fluid to flow inside fluid engine 100. The force achieved in engine 100 can be controlled by adjusting the amount of fluid pumped by fluid structure 102.
The force created in the fluid increases with the density of the fluid used, according to the present invention. Therefore a higher fluid density (e.g., a liquid) results in a lower fluid velocity requirement to create a given output power. The input power requirement is a consideration during system design based on the tradeoffs between fluid density and fluid velocity. Fluid pressure loss due to friction, which increases with fluid velocity and fluid viscosity, and housing requirements should also be considered when choosing between a gas and a liquid.
In
In one embodiment, blades set 166a, 166b and axial blades 108 propel output axle 101 in a rotational motion to transmit the mechanical power output of fluid engine 150. Output axle 101 rotates in preferentially in one direction. Axial blades 108, blades set 166a and 166b rotate as a result of fluid flow pressure generated by fluid structure 109. According to another embodiment, blades inside fluid engine 150 rotate and create vortices in the working fluid such that the fluid flows in rotational motion around an axis. The velocity of the working fluid put the blades into motion, thus doing useful work. The torque in the rotary motion of the output axle 101 may be used to drive machinery.
In one embodiment, a fluid structure (e.g., fluid structure 102 or 109) may locate anywhere within the fluid engine to create a desirable fluid flow. More than one fluid structure or set of blades may be provided to drive the fluid to do work on blades. The fluid structure may include one or more mechanisms that allow the blades to be retracted from the fluid path (e.g., folded flat around the axle or to align along the interior wall of housing 110), when no mechanical input power is present to drive the fluid structure, so as to reduce fluid energy loss. In one embodiment, the blades inside the fluid structure may function as a diffuser to convert the rotational fluid to a high pressure fluid without rotation such that the fluid structure need not be continuously powered by an external mechanical power source.
Blades in the fluid structure may be powered by a spiral spring to rotate the fluid. In one embodiment, a torque created from the output axle of a fluid engine can be transmitted back to the input axle to power the fluid structure. Blades creating torque can form fluid passages. Each blade may be adjustable to control the torque generated by the blade. Adjustment may be implemented by controlling the angle of attack or by tilting the blade. Fluid engines 100 or 150 may be configured to be rotary fluid engines.
According to the present invention, a blade with a lift-to-drag ratio greater than 1 can generate a lift force greater than a drag force when a fluid flows across the blade. The blade can be positioned within an enclosed engine to produce a force greater than the force required to move the fluid across the blade for torque creation.
According to another embodiment, fluid engine 700 is provided by modifying the structures of fluid engine 150. Specifically, fluid engine 700 is achieved by replacing blade set 166a of fluid engine 150 with spiral blades 766a and 766b replacing axial blades 108 of fluid engine 150 with spiral blade set 708, and replacing blade set 166b of fluid engine 150 with spiral blades 767a and 767b. Spiral blades 766a and 766b are shown in
When spiral fluid engine 700 starts up, input axle 113 rotates blade set 203 forcing fluid to move upward through center fluid space 130 into upper portion 164. Blades 766a and 766b in upper portion 164 force the fluid to rotate in the opposite direction as input axle 113 rotation. Rotational fluid flows from upper portion 164 to peripheral space 131 where axial blades 108, as shown in
According to another embodiment of the present invention, as shown in
In
In one embodiment, adjustment of blade parameters may be implemented to enable adjustments on the angle of attack, surface area and turning with a range sufficient to maximize L/D ratio or lift force generated by the blade. Blades that create torque may be tilted, adjusted in referencing the fluid flow direction, fluid velocity and fluid motion to maximize the torque creation. Blades may be adjusted to have horizontal movement, up or down, and turning. The fluid engine's thrust output may be maximized by altering the wing reference area, angle of attack.
In one embodiment of present invention, blades creating torque are coupled to interior wall of housing of a fluid engine, the housing of the fluid engine rotates. As discussed above, fluid engine 100 and fluid engine 150 can be rotary engines. The rotary motion of the rotary engines may be used to create thrust or torque. The blades creating torque may be located in anywhere where torque creation can be achieved. In another embodiment, the blades inside the housing of a fluid engine may form continuous or discontinuous, enclosed or unenclosed channels for working fluid to flow across. A fluid structure for driving fluid flow may be used in each channel.
Working fluid flowing across the blades at an optimum angle of attack and high lift-to-drag ratios can maximize the torque created by the blades. The amount of power output to run a fluid engine is the fluid angular velocity difference between the outward flow and the inward flow of the fluid structure.
Blades shown in figures are positioned to best demonstrate the present invention. These figures show aerodynamic blades having zero angle of attack and other blades being straight. Blade geometry and position are dependent on many engine design parameters including the fluid flow path, fluid motion, fluid velocity and blade angle of attack to create greatest lift-to-drag ratio.
Wings, blade with air-foil shape sections and airfoil means objects with aerodynamic effects in this application. Any object with aerodynamic effect may be suitable to implement present invention. According to the present invention, working fluid inside a fluid engine moved by a fluid structure (a structure having an axle and a set of blades) may function as an impeller, a propeller, a pump, a compressor, a fan or a blower, depending on the configuration of the set of blade and the applications of fluid engine applications. Some examples of such a fluid structure are fluid structure 102 of fluid engine 100, fluid structure 109 of fluid engine 150 and fluid structure 109 of fluid engine 300. In one embodiment, blade set of a fluid structure may be located in peripheral fluid space 131.
According to the present invention, blades creating torque and blades moving fluid may be coupled to the same axle. According to the present invention, blades creating torque and blades moving fluid may be coupled to or arranged on the same internal structure of a fluid engine.
In one embodiment, gases are used as the working fluid to circulate inside fluid engines. Fluid circulation inside fluid engines can be powered by heat energy. Fluid engines may convert heat energy to rotational mechanical energy by heating in one or more areas and cooling in one or more areas. The fluid engine may therefore maintain a temperature difference to keep flow circulation.
According to another embodiment of the present invention, heat engines, powered by heat energy with two areas inside the fluid engines with a temperature difference, can also benefit from using aerodynamic blades as previously described. The temperature difference between two areas inside the heat engine is used to keep fluid circulation within the engine. Torque generated by a heat engine can be created by the working fluid flowing across one or more aerodynamic sets of blades in configurations similar to fluid engines in accordance to the present invention.
Heat engine 1000, which is powered using heat energy, is constructed by modifying structures of fluid engine 100. Fluid structure 102 of fluid engine 100 (includes input axle 101 and radial blades 106) is replaced with one or more heating areas in upper portion 104 and one or more cooling areas in lower portion 120. Radial aerodynamic blades 106 in upper portion 104 and a set of similar aerodynamic blades in lower portion 120 may be provided to create torque. Separator 111 is used as an insulator between heating area in upper portion 104 and cooling area in lower portion 120. Working fluid inside upper portion 104 moves outward toward peripheral fluid space 131 then moves from peripheral fluid space 131 to center fluid space 130 through lower portion 120 to form circulation of fluid flow. Torque is created by working fluid flowing across axial blades 108, radial aerodynamic blades 106, support elements 112 (may be blades with aerodynamic effect) and any aerodynamic blades configured to contribute to generating torque.
In one embodiment, heat engine 1000 has a fluid circulation in upper portion 104 that moves inward toward center fluid space 130, moves to lower portion 120 through center fluid space 130, and moves from lower portion 120 to upper portion 104 through peripheral fluid space 131. Aerodynamic blades can be placed at any suitable location to create torque for heat engine 1000. In one embodiment, heat engine 1000 has working fluid rotating from upper portion 104 to lower portion 120 through peripheral fluid space 131 and rotating from lower portion 120 to upper portion 104 through center fluid space 130, as a result of the rotation of axial blades 108 and radial aerodynamic blades 106. Rotational fluid flow from upper portion 104 to lower portion 120 creates a downward draft surrounding an upward draft created by rotational fluid flow from lower portion 120 to upper portion 104. Rotational fluid flow may induce a spiral fluid flow.
In one embodiment, heat engine 1500 powered by heat energy can be constructed by modifying fluid engine 150 by replacing fluid structure 109 with one or more heating areas in upper portion 164 and one or more cooling areas in lower portion 170. Axial aerodynamic blades may be oriented in center fluid space 130, radial aerodynamic blades 166a and 166b may be placed separately in upper portion 164 and lower portion 170 to create torque.
In one embodiment, heat engine 3000 powered by heat energy can be constructed by replacing fluid structure 109 (include input axle 113 and blade set 203) of fluid engine 300 with heating mechanism in peripheral portion of extension chambers 301, 302, 303 and 304, and providing cooling mechanism in a lower portion of fluid chamber 307. The temperature difference in heat engine 3000 causes fluid flows from a lower portion of fluid chamber 307 outwardly toward lower portions 301b, 302b, 303b and 304b by centrifugal force created by the rotation of the heat engine 3000. Fluid then flows toward upper portions 301u, 302u, 303u and 304u with centrifugal force created by rotational motion of heat engine 3000. The fluid expands in the peripheral portion of extension chambers 301, 302, 303 and 304 and travels back to fluid chamber 307 through upper portions 301u, 302u, 303u and 304u. Aerodynamic blades 305 create torque when the fluid flows across and rotates heat engine 3000.
Heating and cooling elements can be embedded in aerodynamic blades, support elements, separator or structures inside housing to change the velocity of fluid and the density of fluid for maximizing lift force for torque creation. Fluid volume control mechanism may be used to alter fluid velocity for aerodynamic blades.
The above detailed description is provided to illustrate specific embodiments of the present invention and is not intended to be limiting. Numerous variations and modifications within the scope of the present invention are possible. The present invention is set forth in the accompanying claims.
Claims
1. An engine, comprising:
- a housing including an interior space divided into a first portion and a second portion that are connected with each other;
- a working fluid filling the interior space which flows, during operation, between the first portion and the second portions; and
- one or more airfoils positioned within the interior space in the circulation path of the fluid flow.
2. An engine as in claim 1 wherein, during operation, a temperature difference is created between the first portion and the second portion, such that the working fluid flows between the first portion and the second portion.
3. An engine as in claim 2, wherein the temperature difference is to achieve a fluid flow velocity within the interior space.
4. An engine as in claim 1 wherein, during operation, a propeller drives the working fluid between the first portion and the second portion.
5. An engine as in claim 1, wherein the airfoils are positioned relative to the fluid flow to creates torque.
6. An engine as in claim 1, wherein a fluid structure drives the working fluid between the first portion and the second portion.
7. An engine as in claim 6, wherein the fluid structure is driven by a power source.
8. An engine as in claim 6, wherein the fluid structure comprises blades positioned to increase fluid pressure in the fluid flow.
9. An engine as in claim 8, wherein the blades comprise reaction blades.
10. An engine as in claim 8, wherein the blades comprise aerodynamic blades.
11. An engine as in claim 1, wherein the first portion and the second portion is connected by a central portion and a peripheral portion.
12. An engine as in claim 11, wherein the airfoils are positioned at the peripheral portion.
13. An engine as in claim 1, wherein airfoils are positioned to create a lift force in a predetermined direction.
14. An engine as in claim 13, wherein the predetermined direction is a direction of rotational motion resulting from the lift force.
15. An engine as in claim 1, wherein the airfoils comprise axial blades.
16. An engine as in claim 1, further comprising support structure securing airfoils to the housing.
17. An engine as in claim 16, wherein the airfoils further comprise axial blades.
18. An engine as in claim 1, wherein a portion of the airfoils form the support structures.
19. An engine as in claim 1, wherein the airfoils comprise radial blades.
21. An engine as in claim 1, wherein the airfoils are provided on interior walls of the housing, such that the lift force puts the housing into rotation motion,
22. An engine as in claim 11, wherein the peripheral portion opens into a plurality of extension chambers, wherein a portion of the airfoils is placed in the extension chambers to provide torque.
23. An engine as in claim 24, wherein each extension chamber includes a nozzle through which the working fluid leaves the extension chamber.
24. An engine as in claim 22, wherein the fluid flow over the portion of the airfoils placed in the extension chambers create torque that drives a rotational motion of the housing to drive an output axle.
25. An engine as in claim 23, wherein the working fluid leaving the extension chamber is directed towards a set of objects provided on a rotatable structure, such that the working fluid flowing over the set of the objects provides torque to the engine.
26. An engine as in claim 11, wherein each extension chamber has a first opening and a second opening into the peripheral portion, and wherein fluid flow from the peripheral portion into the extension chamber through the first opening and from the extension chamber into the peripheral portion through the second opening.
27. An engine as in claim 26, wherein fluid circulates between each extension chamber and the peripheral portion.
28. An engine as in claim 22, wherein the torque provided by airfoils in the extension chamber sets the housing into rotational motion to drive an output axle.
29. An engine as in claim 1, wherein the lift-to-drag ratio of an airfoil is greater than one.
30. An engine as in claim 1, wherein an angle of attack of an airfoil, relative to the working fluid flow, is adjustable.
31. An engine as in claim 30, wherein the angle of attack is adjustable to achieve a better torque.
32. An engine as in claim 1, wherein an angle of attack of an airfoil is adjustable.
33. An engine as in claim 1, wherein the airfoils comprise spiral blades.
34. An engine as in claim 1, wherein the housing comprises a tubular portion rotatable about an axis.
35. An engine as in claim 1, wherein the working fluid comprises a gas.
36. An engine as in claim 35, wherein the gas is pressurized.
Type: Application
Filed: Sep 22, 2008
Publication Date: Mar 25, 2010
Inventors: Guy Silver (Cupertino, CA), Juinerong Wu (Reno, NV)
Application Number: 12/235,395
International Classification: F01K 27/00 (20060101); F01D 7/00 (20060101);