CA2688872A1 - A method for efficiently generating and extracting power from an air flow for useful work - Google Patents

Abstract

This invention is a method for efficiently generating and extracting power from a flow of air so as to do useful work. The acceleration of an air flow through a flow swirler generates swirling or circulatory kinetic energy which is then coupled to an external motor or mechanical means for useful work. The essential elements of the invention are an air flow and a flow swirl means which also serves as the power take-off means,

Description

A Method for Efficiently Generating and Extracting Power from an Air Flow for Useful work Using compressible fluids, especially hot gases and steam, to generate useful work is usually a procedure of heating a gas and then extracting the resulting pressure-volume energy change of expansion to produce external work, this process having low efficiency as described by the Carnot Cycle in the theory of heat exchange by a non-isentropic thermodynamic process.
The Carnot efficiency is given by the formula Eff. = 1 - T/To = AT/To, where T is the gas temperature at the end of the cycle and To is the referemce temperature before heat input at the beginning of the Carnot work cycle [Ref. 1,2].

Devices for transforming air energy into work by creating kinetic energy of flow, rather than energy of expansion or contraction, are less useful and less numerous, for example, vacuum pumps, vacuum cleaners, air blowers and so on., In these flow devices linear air flow Vi;n. is produced from the internal pressure- volume (heat) energy of the gas by an isentropic energy transformation process following the isentropic relationships c2 /c 2 = p/p wn+2> = p/ p ' /n) = T/To = [I - V2/C02) ]
where c is the acoustic wave speed, p is pressure, p is the air density, T is the air temperature and c is the flow speed. The subscripts (o) refer to static or zero velocity conditions.

Although the transformation of p-v energy into linear flow isentropically is very efficient, the ultimate work taken- off from the device is commonly not very efficient, vacuum cleaners, for example, are often less than about 37% efficient.

Again, windmills are another example of such air motors in which an essentially linear air flow V1 1. from wind is used to drive a freely rotating propeller which in turn is attached to a shaft driving an electric generator or motor. The so-called Betz Limit then sets 59.3 % as the maximum amount of wind kinetic energy ( K.E. = 1/2 mV2) that can be extracted by any propeller or turbine to do useful work. Other losses such as friction, power take-off transfer losses etc, are in addition to this Betz Limit loss [Ref. 1].

Considering that the total p-v energy of a mass of air, even at sea-level conditions (20 degrees C and 1000 millibars ) is large, and isentropic transformation of internal or static air energy to kinetic or flow energy is so efficient, it is natural that the search for a means for a) generating the larger isentropic flow velocity and b) then extracting more useful kinetic energy as work is seen as a worthwhile endeavour.

Indeed, it is well recognized that large tangential wind speeds are generated in atmospheric vortices such as tornadoes, waterspouts, dust devils and the like.
Recently, the inventor has shown that all these atmospheric phenomena are in their initial stages essentially isentropic transformations of p-v energy directly into tangential flow energy [Ref. 3 ]. It is natural therefore to look to swirling, circulating and tangential flows as an attractive means of tapping into internal pressure -volume energy of air and transforming it efficiently into potentially useful kinetic energy.

The direct prior art is disclosed in Canadian Patent Application 2, 635, 304 "
Method for Efficiently Transforming Heat Energy into Useful Work.. Filed July 25, 2008.[ Ref. 4].

The cited disclosure teaches the setting up of a vortex inside a protective cylinder and states (at page 3, lines 13-14 of the specifications) " the means for extracting the increased kinetic energy of the invention to produce exterior work can be a turbine axially mounted into the output end of the vortex cylinder.... "

Clearly, the prior art cited here teaches first forming a complete vortex inside a protective cylinder, and moreover this vortex is separate from a turbine take-off means located at the output end of the vortex tube or cylinder. Thus, we have a means for forming a fully developed vortex, said vortex contained in a separate cylinder, and a separate turbine power take-off means located at the output end of the said cylinder.

In the present invention, in contrast, an entirely different and novel method is used which consists of setting up a swirling and accelerating air flow through an axially mounted flow swirler which is itself freely able to rotate on its cylindrical axis. This has eliminated (a) the separate vortex, (b) the separate vortex cylinder and (c) the separate turbine power-take off means at the exit end of the said cylinder in the prior art. In addition, the present invention has quadrupled the kinetic and rotational generated energy at effectively 100 %
efficiency, and greatly reduced the take- off losses inherent in the previous art ( because of the Betz Limit for windmill turbines, for example).

In the present invention, the swirling flow- accelerating mechanism itself becomes the rotational power take off means, automatically configured to couple, by any standard clutch or coupler, to any desired exterior mover or machine. The method of the present invention is thus reduced to (1) a flow entering through (2) a freely rotatable flow swirler means which at the same time forms the swirl, accelerates the swirled flow, increases the flow kinetic energy and accepts and stores the rotational energy available for export to do useful exterior work. It is indeed startling in its economy, its simplicity and its improvement on any existing energy source or method s for the generation and supply of clean economical energy.

The "fuel" or energy source for the present invention is air, and so, for continuous operation of the method, a continuous flow of air is required. The source of the flow of air can be, variously, the air flow from a compressed air source or higher pressure reservoir, the suction air flow into an air suction pump or vacuum pump, the natural flow of air in wind, the relative flow of air past a moving platform when the method is practiced on a moving platform such as an airplane, a moving automobile, truck, train or railway vehicle, or a moving ship. The source of the air flow an also be a convective up-current of warmer or less dense air, a hot gas rising through a chimney, or a natural convective up-current in the atmosphere , and so on.

It is pointed out that, while the present disclosure and application deals specifically with air, the inventive principles disclosed can be applied equally to any compressible fluid, either gas or liquid.

In the present invention the term "flow swirler" denotes any flow means or device for guiding an air flow into a swirling, circulatory or vortical motion; this includes any substantially cylindrical shaped swirler having a helical shaped duct or grouping of helical or spiral or scroll shaped ducts for guiding an air flow into a circulatory motion while simultaneously reducing the radius of tumin. of the flow as it progresses through the spiral duct towards the smaller radius of the outlet port of the flow swirler means ; this decreasing radius of flow increases the flow speed automatically because of the action of the law of conservation of angular momentum which requires an increase in flow speed with decrease in radius of turning of the flow. Examples of flow swirlers in the present context would be the tangential disposed intake ducts of a cyclone dust separator, the various helical swirl tubes also used in dust separators [ Ref. 5], centrifugal pumps [Ref.I]. etc. . The conservation of angular momentum law ensures that if V(1) denotes the inlet speed at the flow device's greater inlet radius r(1), and V (2) is the flow speed at the smaller, inner exit flow radius r(2), then V (I) x r(1) = V(2) x r(2) = constant, so that V(2) must be larger than V(1) in the ratio r(l)/ r(2). Clearly, flow swirling is a readily available means for increasing the kinetic energy content of any air flow, and since the transformation occurs isentropically there is no energy loss or inefficiency.

By way of contrast, for example, a certain vacuum device requiring 1600 watts of driving power can produce a maximum air flow of 600 watts which is only about 37%
efficiency with respect to the transformation of internal air energy into linear flow.

But if now the Vlineaz flow is, instead, passed through an air swirler of radius ratio r(1)/r(2) , then the resulting swirled flow velocity Vs, , at the same mass flow, will have been changed to a much higher kinetic energy flow, since Vs is larger than that of Vi;neaz in the ratio r(1)/r(2) ; the magnitude of the speed increase is thus free to be set by the design of the device through the choice of r(1)/r(2) thus allowing the magnitude of the swirled flow velocity to be set more or less as high as desired, apart from inherent losses such as friction, etc. For example, if we were to set r(1) / r(2) large enough to let V( 2) reach sonic speed ( about 300 m/s at sea level) then the available kinetic energy per kilogram of air passing through the swirler per second would be '/2 x (1) x (300)2 = 45,000 watts.

This feature of sending a low speed flow through a spiral shaped duct or flow swirler so as to induce a higher energy flow at a smaller radius of flow curvature is an essential element of any improved air power system, and, as will now be explained, the present invention accomplishes this in a novel, much improved and efficient method.

A second necessary element is a means for efficiently extracting or taking-off of the increased generated rotational power of the swirling air so as to do useful work.

In conventional usage, flow swirlers which channel dust-laden air through their scroll shaped or spiral shaped ducts or flow passages in, say, a cyclone dust separator [4] are fixed in place and do not move.

In the present invention, however, in an entirely novel way, the flow swirler through which the airflow is directed, is installed so as to be free to rotate around the swirler's own cylindrical axis.

In the case of a vacuum or suction induced air flow, the swirler's cylindrical axis is set parallel to the general suction flow axis so that the swirler itslf is free to rotate around its own cylindrical axis, that is, transverse to the general flow direction.

In the case of a push or other pressure induced air flow, say from the wind, or on a moving platform, the flow swirler's cylindrical axis is oriented across, that is at right angles to the general flow direction, and the swirler itself then is free to rotate around its own cylindrical axis , that is, parallel to the general air flow direction.

This freely rotating air swirler accomplisher two very important things at once. First, the air, which is accelerating through the swirler because of the decreasing spiral or scroll radius of its air passages towards the core and exit of the swirler, exerts on the said swirler an equal and opposite Newtonian reaction force- one equal in magnitude to the force which is accelerating the air itself through the swirler, but acting in the opposite direction to that flow's accelerating force.

Thus, the freely rotatable swirler rotates against the direction of the air flow streaming into the swirler inlet ports ats the swirler outer rim at radius r)1) and then accelerating on through its helical ducts to the swirler exit at an inner radius (r(2) . Since this speed-up of the rotating swirler is opposite in rotational direction to the inflowing air, the relative air velocity with respect to the swirler is increased in direct proportion to the flow speed-up through it. The final stable rotation speed of the swirler is given by theory and verified by experiment to be close to double the flow rotation speed attainable from the same inlet air flow velocity but with the swirler fixed in the conventional fashion so to be non-rotatable .

Mathematically expressed, we have for the rotating swirler case Kinetic energy ='/2 m V2 ='/2 m [V(1) x r(1)/r(2) x 2]2 where the new velocity factor 2 accounts for the doubling of the flow speed through the swirler.
The rotational energy equation is of the general form Kinetic Energy = IOJ2 = '/2 m [V(1) x r(I)/r(2) x 2]2 , where I is the rotational moment of inertia and w is the rotation rate in radians per second.. We see that the rotation of the swirler automatically quadruples the kinetic energies of flow and rotation..
Second, since the flow swirler is now itself rotating with rotational kinetic energy (1(02) of the flow itself, it therefore also has automatically itself become the necessary flow power take off means completely eliminating the need for inserting any inefficient supplementary flow turbine means, propeller means, or the like for extracting the flow power to do useful work. In effect, the rotating flow swirle rmeans has itself become a reaction- type power take-off means which is now directly able to couple to any exterior motor, generator, or other mechanical machine desired to accomplish useful work. at close to 100% efficiency. The method of the present invention is thus one of truly remarkable simplicity, efficiency and economy.

As to the economic advantages of the invention they are almost self evident: a huge source of clean energy - the atmosphere itself- at a time when clean, economical and environmentally friendly energy is universally seen as needed for the well being of the world.
The invention is also very flexible in its forms and applications and indeed is suitable to be used in tandem with most current prime movers rather than simply competing with them.

References 1. Standard Handbook for Mechanical Engineers. T. Baumeister, ed.. Seventh edition, McGraw-Hill Book Company, New York.1958.

2. Shapiro, A. H., The Dynamics and Thermodynamics of Compressible Fluid Flow.
2 vols.
Wiley and Sons, New York.1953.

3. Power, Bernard A., Tornado-genesis by an IsentropicEnergy Transformation.
Posted June 21, 2008 on Website www.energycompressibility. info.

4. " Method for Efficiently Transforming Heat Energy into Useful Work..
Canadian Patent Application 2, 635, 304. Bernard A. Power, Inventor. Flied July 25, 2008..

5. Hoffmann, A. C. and L.E. Stein. Gas Cyclones and Swirl Tubes. 2 a. Ed.
Springer, berlin.
2008.

Claims (6)

1. A method of efficiently generating and extracting power from a flow of air for useful work comprising:

Causing a flow of air to enter into and accelerate through a flow swirler means, such as for example a suitably curved duct or scroll or spiral shaped flow swirler means, said flow swirler means having its flow exit port at a smaller scroll or spiral radius than its inlet port radius, thereby causing said air flow passing through said flow swirler to accelerate as required by the law of conservation of flow angular momentum;

said flow swirler being axially mounted so as to be freely rotatable around its own cylindrical axis, said flow swirler receiving, from the air accelerating through it, the reaction force and the rotational kinetic energy equal in magnitude to the rotational energy of the air flow itself, but acing to rotate the flow swirler in the opposite direction of rotation, said swirler thus effectively doubling the relative air flow speed through the swirler and generally quadrupling the rotational kinetic energy available from a fixed, non- rotatable swirler under the same flow input conditions; said rotating flow swirler thus acting automatically as a power take-off means for exporting said generated rotational energy to any external motor or machine supplied with any standard power- train coupling means.

2. A method as in Claim 1 wherein the source of the air flow is a vacuum suction means, and the flow swirler means is axially aligned with the general suction flow direction

3. A method as in Claim 1 wherein the source of the air flow is a pressure reservoir and the flow swirler rmeans is axially aligned transverse to the general air flow direction.

4. A method as in Claim 1 wherein the source of the air flow is the atmospheric wind and the flow swirler means is axially aligned transverse to the wind flow direction.

5. A method as in Claim 1 wherein the source of the air flow is the air passing a moving vehicular platform upon which the method is being practiced and the flow swirler is axially transverse to the general air flow passing the platform .

6. A method as in Claims 1, 2 and 3 wherein some of the power generated and taken-off is then fed back and used to provide the power needed to provide the basic air flow required for the continuous operating of the method, thus rendering the method substantially self- sustaining, .both with respect to the operation of the method and in the useful excess power production.