GB2431434A

GB2431434A - Jet engine with variable area passageway

Info

Publication number: GB2431434A
Application number: GB0620191A
Authority: GB
Inventors: Alan O'keefe
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-10-14
Filing date: 2006-10-12
Publication date: 2007-04-25
Also published as: GB0520856D0; GB0620191D0

Abstract

The jet engine, comprises at least one fluid passageway, which may be arranged between at least one inlet and at least one outlet; fluid heating means arranged to heat fluid within the fluid passageway; and passageway control means for selectively controlling a cross sectional area of a section (such as a fluid compression section) of the passageway. The control means may comprise a longitudinally movable flow diversion structure 16 operated by levers 24,25. A fan 10 may be driven by a turbine 12, which receives hot gases from a combustion chamber and fluid (via conduits 46,48) from a flash boiler, a bottom compartment of which is supplied with fluid, such as water, by a tube 40.

Description

1 2431434

JET ENGINE

The present invention relates to a jet engine and in particular, although by no means limited to, a jet engine for driving a vehicle.

A jet engine operates by ejecting a stream of hot gas and, due to Newton's third law of motion, creates thrust in a direction opposed to the stream of gas.

Air is drawn into a front of the jet engine from the surrounding environment. The in-drawn air is compressed and then combined with fuel, which becomes atomised. A source of combustion, such as a flame, ignites the atomised mixture. The resulting combustion greatly increases the energy of the gasses and expands the air, which is then exhausted out of a rear of the engine as the stream of hot gas. The expanding air is exhausted from the rear of the engine due to a path of least resistance, the forward path being effectively blocked' by the incoming compressed air.

A variation of a jet engine is a gas turbine engine, which includes a vaned rotating disc or impeller fan arranged at a front of the engine and a bladed rotor or turbine fan arranged at a rear of the engine.

The impeller fan operates to additionally draw or suck air into the engine. The air is compressed, mixed with fuel and combusted as before. The expanding air is directed on to the blades of the turbine, in order to drive the turbine. The turbine creates an exhaust stream, which results in forward motion, and a shaft driven by the turbine can be used to drive a generator or alike mechanical device.

Currently a jet engine or gas turbine engine exhibits poor efficiency under an alternating load.

An aim of the present invention is to improve the operation of a jet engine or a gas turbine under an alternating load.

In addition, it is desired to produce a more efficient jet engine.

A further aim is to provide a jet engine or a turbine suitable for use in driving a vehicle.

It is an additional aim of the present invention to attempt to overcome at least one of the above or other disadvantages.

According to the present invention there is provided an apparatus and method as set forth in the appended claims. Preferred features of the invention will be apparent from the dependent claims, and the description which follows.

According to one aspect of t)he present invention, there is provided a jet engine comprising at least one inlet and at least one outlet; at least one fluid passageway arranged between the at least one inlet and the at least one outlet; fluid heating means arranged to heat fluid within the fluid passageway; and means for selectively controlling a cross sectional area of a section of the at least one fluid passageway.

Preferably, the section comprises a fluid compression section.

Preferably, the means is arranged in use, to vary the fluid compression in the fluid compression section.

Preferably, the fluid compression section comprises an annular fluid passageway.

Preferably, the cross-sectional area of the annular fluid passageway is variable.

Preferably, the fluid compression section is arranged, in use, upstream of a combustion section. Accordingly, the means is arranged to vary the compression at the fluid prior to (and preferably immediately prior to) the fluid entering the combustion section.

Preferably, the jet engine, in use, comprises a forward facing fluid inlet.

Preferably, the jet engine, in use, comprises a rearward facing outlet.

Preferably, the rearward facing outlet is an exhaust.

Preferably, the engine comprises an outer body.

Preferably, the outer body has a generally cylindrical cross section defining a longitudinal axis of the engine.

Preferably, the at least one inlet is arranged, in use, in a forward end of the body.

Preferably, the at least one outlet is arranged, in use, in a rearward end of the body.

Preferably, the fluid passageway is arranged along a longitudinal axis of the body.

Preferably, the fluid passageway is generally concentric with the longitudinal axis.

Preferably, the fluid passageway generally converges toward a mid-point of the engine.

Preferably, the means for selectively controlling a cross sectional area of the at least one fluid passageway is a section of at least a section of the fluid passageway having a variable cross section.

Preferably, the cross sectional area of the fluid passageway is controllable by a user.

Preferably, the fluid passageway comprises a first portion having a substantially constant cross-section.

Preferably, the fluid passageway comprises a second portion having a generally reducing cross section.

Preferably, the second portion has a generally convergent inner profile.

Preferably, the fluid passageway comprises a third portion having a generally constant cross section.

Preferably, the outer surface of the third portion has a substantially constant radius.

Preferably, the fluid passageway comprises a fourth portion having a variable cross section.

Preferably, the fourth portion has a generally convergent outer profile.

Preferably, the fluid passageway comprises a fifth section having a substantially constant cross-section.

Preferably, the fluid passageway comprises a sixth section having a generally increasing cross section.

Preferably, the sixth section comprises a generally divergent inner profile.

The jet engine may comprise a flow diversion structure within the fluid passageway operable to control a cross sectional area of at least a section of the fluid passageway between the at least one inlet and the at least one outlet.

Preferably, the flow diversion structure is moveable within the fluid passageway, such that the cross sectional area of at least a section of the fluid passageway can be varied.

Preferably, the flow diversion structure is longitudinally moveable within the fluid passageway.

Preferably, the flow diversion structure is longitudinally moveable between a first position and a second position.

Preferably, the first position is a forward position and the second position is a rear position.

Preferably, the flow diversion structure is rnoveable with respect to a section of the fluid passageway having a generally divergent outer profile, such that the cross sectional area of the fluid passageway can be controlled.

Preferably, the flow diversion structure is arranged generally concentric within the fluid passageway, such that fluid flowing through the passageway flows between an outer surface of the flow diversion structure and an inner surface of the fluid passageway.

Preferably, the flow diversion structure is substantially cylindrical and is arranged within the fluid passageway.

Preferably, the flow diversion structure is concentric with the fluid passageway.

Preferably, at least part of an outer profile of the flow diversion structure diverges parallel to a diverging portion of the fluid passageway.

Preferably, the flow diversion structure comprises a first portion having a generally divergent outer profile.

Preferably, the flow diversion structure comprises a second section having a generally constant radius outer profile.

Preferably, the flow diversion structure comprises a third portion having a generally divergent outer profile.

Preferably, the flow diversion structure comprises a fourth section having an outer profile with a generally constant radius.

Preferably, the third portion of the flow diversion structure and fourth portion of the fluid passageway cooperate, such that the cross sectional area of the fluid passageway can be controlled.

Alternatively, the flow diversion structure may be formed of first and second relatively moveable parts. The second, rearward, section may be statically arranged. The first, forward, section may be moveable so as to control the cross sectional area of the fluid passageway. The first section may be moveable forward and backward.

Preferably, the jet engine comprises means operable external of the body to move the flow diversion structure between the first and second positions.

Preferably the jet engine comprises an impeller fan arranged at a front end region of the engine.

Preferably, the impeller fan operates to draw ambient gas into the fluid passageway.

Preferably, the impeller fan is arranged within a forward end region of the fluid passageway.

Preferably, the impeller fan is arranged within the first portion of the fluid passageway.

Preferably, the impeller fan comprises a central disc and a plurality of outer vanes.

Preferably, the impeller fan rotates in use in a first direction.

Preferably, in the first position, the flow diversion structure is arranged toward the impeller fan.

Preferably, the engine comprises a drive shaft extending longitudinally through the engine.

Preferably, the impeller fan is co-operable with the drive shaft, such that rotation of the drive shaft causes rotation of the impeller fan.

Preferably, the jet engine comprises a turbine fan arranged at a trailing end region of the engine.

Preferably, the turbine fan is co-operable with the drive shaft.

Preferably, the turbine fan comprises a central disc and a plurality of outer vanes.

Preferably, the heating means comprises at least one combustion region, within which a gas, fluid or gas and fluid mixture is combusted.

Preferably, the heating means comprises means for mixing fluid within the fluid passageway with a combustible fluid.

Preferably, the heating means comprises means for atomising the combustible fluid.

Preferably, the combustible fluid is petrol.

Preferably, the combustible fluid is aviation fuel.

Alternatively, the combustible fluid may be a combustible gas.

Preferably, the combustible gas may be one of or a combination of, butane, propane or methane.

Preferably, the heating means comprises at least one burner arranged within the combustion region.

Preferably, the jet engine comprises a plurality of burners arranged within the combustion region.

Preferably, the combustion region is arranged in the outer periphery of the fluid passageway between the flow diversion structure and the outer surface of the fluid passageway.

Preferably, the combustion region is arranged between the fifth portion of the fluid passageway and the fourth portion of the flow diversion structure.

Alternatively, the combustion region may be formed between the first and second sections of the flow diversion structure such that a volume of the flow diversion structure is variable.

Preferably, the engine further comprises a fluid heating means for heating a fluid, such that heated fluid is directed toward the turbine fan.

Preferably, the fluid heating means is a flash steam boiler.

Preferably, the fluid heating means is arranged within the flow diversion structure.

Preferably, the fluid heating means is arranged within the portion of the fluid diversion structure inwardly adjacent to the combustion region.

Preferably, the fluid heating means comprises first and second chambers in fluid communication.

Preferably, fluid to be heated is introduced into the first chamber.

Preferably, heated fluid is exhausted from the second chamber to the turbine.

Preferably, a volume of the first and second chambers

is adjustable.

Preferably, the volume of the first and second chambers is responsive to the position of the flow diversion structure.

Preferably, the engine comprises an inlet for introducing fluid to the first chamber.

Preferably, the engine comprises at least one exhaust for directing heated fluid to the turbine.

Preferably, the inlet is suitable for introducing water to the first chamber.

Preferably, the at least one outlet is suitable for directing steam toward the turbine.

The fluid may comprise hydrogen-dioxide and may enter the first compartment in its liquid state (water) and may leave the fluid passage in its gas state (steam).

Preferably, the engine is a Compression Cone Engine.

According to a second aspect of the present invention, there is provided a method of operating a jet engine, comprising inducing fluid into the engine, communicating the fluid through at least one fluid passageway, selectively controlling a cross-sectional area of a section of the at least one fluid passageway, heating the fluid with the passageway and exhausting fluid from the engine.

Preferably, the cross-sectional area of a fluid compression section is varied in use.

Preferably, the cross-sectional area of the fluid passageway prior to the heating means is adjusted.

Preferably, a longitudinal position of a flow diversion structure within the fluid passageway is adjusted.

Preferably, a second fluid is heated within the engine, such that heated fluid is directed toward a turbine fan.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: Figure 1 is a cross sectional side view of a first embodiment of the present invention in a first position; Figure 2 is a cross sectional side view of the first embodiment of the present invention in a second position; Figure 3 is a cross sectional view through line A-A of Figure 1; Figure 4 is a cross sectional side view of a second embodiment of the present invention.

Like parts in Figures 1 and 2 have identical reference nulnera].s, which have been omitted in Figure 2 for clarity.

Figure 1, shows a cross-sectional view of a jet engine along its longitudinal axis. The jet engine comprises an outer casing 2, which extends the extent of the jet engine from a first, front, end region 4 having a forward facing opening or inlet, to a second, trailing or rear, end region 6 having a rearward facing opening or outlet which serves as an exhaust. The inlet and outlet are in fluid communication.

The outer casing 2 is substantially symmetrical about its longitudinal axis, and effectively forms a cylinder having a varying diameter along its length. It will be appreciated that the outer casing 2 may be of any suitable cross section such, as to have at least one inlet and at least one outlet. The casing 2 is formed by materials such as metals, well known in the art that provide sufficient heat resistance and structural rigidity. The casing 2 has a substantially constant wall thickness suitable to withstand the pressures, forces and environmental factors experienced in use. In the preferred embodiment, the casing is manufactured from suitable, metal, composite or other material.

The outer casing 2 is constructed as a single, unitary, section having a series of alternatingly tapering or frusto-conica]. and generally constant diameter sections.

The front end region 4 comprises a first constant diameter section 2a. Extending rearwardly from the first constant diameter section 2a is a first frusto-conical or inwardly tapering section 2b arranged such that the diameter of the outside casing reduces or narrows as the casing extends rearwards from the inlet. The frusto- conical section comprises a circumferential face with a constant gradient or inward taper. A second constant diameter section 2c extends rearwardly from a small end of the first frusto-conical section 2b. Arranged immediately adjacent of the rearward end of the second constant diameter section 2c is a second frusto-conjcal section 2d, which also reduces in diameter aft of the engine or narrows in a rearward direction. A third constant diameter section 2e extends between a small end of the second frusto-conjcaj. section 2d and the small end of a third outwardly tapering frusto-conical section 2f. The third frusto-conical section is arranged such that the diameter increases rearwardly such that the outer casing 2 outwardly tapers in a rearward direction. A fourth constant diameter section 2g extends rearward of a large end of the third frusto- conjcal section 2f and comprises the trailing end region of the outside casing. An end of the third section 2f forms the exhaust or outlet.

Whilst the frusto-conical or tapering sections 2b, 2d, 2f, are described as having a constant outer taper or gradient, it will be realised that these sections may be curved.

The jet engine further comprises an axle 8 or shaft which extends along the longitudinal axis of the engine, as defined by the outer casing 2. The shaft is concentric with the outer casing 2.

An impeller fan 10, which is well known in the art and comprises a vaned rotating disc (a rotatable disc having a vaned outer edge), is arranged at the front end region 4 of the jet engine, within the first constant diameter section 2a of the outer casing 2. It will be realised that the vanes may extend to a centre of the fan for increased air throughput. The impeller fan 2 is connected to the axle 8 such that it rotates about the longitudinal axis of the engine within the outer casing 2 in cooperation with the axle 8. The vanes of the impeller fan 10 are arranged such that, when in use and when the axle 8 is rotated in a first direction, they draw air into the engine by forcing air rearward. In the preferred embodiment, as shown, the vanes of the impeller fan 10 extend partially outward from the central disc. However, it is appreciated that the vanes could also extend substantially the full radius of the impeller fan 10.

A turbine fan 12 is arranged at the trailing end region 6 of the jet engine, within the fourth constant diameter section 2g of the outer casing 2. Turbine fans are well known in the art and consist of a vaned rotating disc. Again, the vanes may extend to a centre of the fan.

The turbine fan 12 serves to convert kinetic energy of airflow through the engine into rotational movement of the axle or shaft 8. The turbine fan 12 is connected to the axle 8 such that the turbine fan 12 rotates about the longitudinal axis of the outer casing 2. The turbine fan 12 is such that when fluid, for example air, flows through the engine past the turbine fan 12, the turbine fan 12 is urged to rotate the axle 8 in the first direction.

The vanes of the turbine fan 12 extend partially from the outermost limits of the turbine to a disc edge spaced from the central axis of the turbine fan 12. A diverging section of the turbine fan 12 comprises a frusto-conical section that extends forwardly from the turbine fan 12 such that the large diameter of the frusto-conical section is arranged within the engine proximate to the radial limit of the turbine's vanes. This conical section serves to increase compression of the airflow, thus increasing a velocity of the flow past the vanes of the turbine fan 12.

The jet engine further includes a flow diversion structure 16 that extends between a position rearward of the impeller fan 10 and a central region of the engine forward of the turbine 12. In use, the flow diversion structure 16 is arranged within the outer casing 2 and creates a radial or annular passage between the inside or inner surface of the outer casing 2 and an outer surface of the structure 16.

Air flow through the engine is diverted around the flow diversion structure 16 along a radial outer periphery of the engine. The flow diversion structure 16 is substantially symmetrical about the longitudinal axis of the jet engine. The outer surface of the flow diversion structure is substantially continuous and comprises a series of alternating frusto-conical and constant diameter sections, complimentary to the outer casing 2.

The first or forward end region of the flow diversion structure 16 comprises a first frusto-conical section 16a, such that the diameter of the inner structure gently increases rearwards of the impeller fan 10. A small diameter, forward, end of the flow diversion structure 16 is therefore arranged generally adjacent to the impeller fan 10 and has a diameter substantially the same as the central disc of the impeller fan 10 from which the vanes of the impeller fan 10 extend. In the case that the impeller fan has vanes extending to a centre of the fan, the first frusto-conical section 16a may extend to a forward point adjacent to the fan 12 and diverge rearwardly of the fan 12.

Extending aft or rearwardly from the large diameter end of the first frusto-conjca]. section 16a is a first constant diameter section 16b. In the preferred embodiment, the length of the first constant diameter section 16a is substantially the same as the length of the second constant diameter section 2c of the outer casing 2.

A second frusto-conical. section 16c extends rearwardly from the first constant diameter section 16b and is arranged such that the outer diameter of the flow diversion structure 16 decreases aft or rearwardly.

The second frusto-conical section 16c comprises a circumferential outer surface having the same gradient as the second frusto-conical section 2d of the outer casing 2. In this way, the cross sectional area of the passage between the corresponding sections of the flow diversion structure 16 and the outer casing 2 remains substantially constant, i.e. the surfaces are substantially parallel. A second constant diameter section 16d extends rearwardly from the small diameter of the second frusto-conical section]. 6c.

As will be explained later, the flow diversion structure 16 is longitudinally moveable within the engine to control airflow.

The first frusto-conjcal 16a, first constant diameter 16b, and second frusto-conjcal sections of the flow diversion structure 16 are substantially hollow and are defined by walls with sufficient thickness and using materials with adequate properties, as is well known in the art, to withstand the environmental conditions and forces exerted on them in use. The first end region 16a includes a forward end face that closes the forward end of the flow diversion structure 16. The forward end face includes an aperture through which the axle 8 extends through the structure 16.

The portion of the radial passage defined between the second constant diameter section 16d of the flow diversion structure 16 and the equivalent section of the outer casing 2e forms a combustion chamber 3. The combustion chamber 3 comprises four axial fins 18 that extend between the outer surface of the flow diversion structure 16 section and an inside circumferential face of the third constant diameter section 2e of the outer casing 2. The fins 18 extend at tangents to the flow diversion structure 16 and are arranged at ninety degrees to each other, as shown in Figure 3. The fins 18 therefore form axial walls of the combustion chamber 3, such that the toroidially shaped combustion chamber is divided into four equally sized segments. It will be realised that the combustion chamber can be divided up into a different number of segments by using a different number of fins 18.

The fins 18 create a plurality of combustion chambers 3 about the second constant diameter section 16d of the flow diversion structure 16, in the radial passage created between the flow diversion structure 16 and the outer casing 2. First and second burners 20, 21 are arranged within the upper combustion chambers 3, spaced axially from each other, within in each chamber. The burners 20, 21 are fixed fast to the outside casing. Burners are a well-known apparatus in the art. As will be appreciated, the burners may be supplied with a liquid fuel, such as petrol, or a gaseous fuel such as butane, propane or methane, or a combination thereof.

Two handles or operating levers 24, 25 extend radially outward from the flow diversion structure 16 preferably from the first constant diameter section l6b. The operating levers 24, 25 are preferably rods and are cooperable with the flow diversion structure 16. The operating levers 24, 25 extend through elongate longitudinal apertures in the outer casing 2 and are operable by a user from the external environment.

Radial flanges 26, 27 arranged perpendicular to and about the handles 24, 25 retain the first end of the flow diversion structure 16 in concentric alignment with the outer casing 2. The second end of the flow diversion structure 16 is held in longitudinal alignment with the outer casing 2 by the concentric intimate arrangement of the fins 18 with the outer casing 2.

The flow diversion structure 16 is free to move axially, relative to the outer casing 2. The intimate arrangement of the fins 18 and outer casing 2 does not restrict the axial movement of the flow diversion structure 16 and the handles 24,25 are free to move within the elongate apertures.

In a first or forward position of the flow diversion structure, as shown in Figure 1, the rearward most end of the first constant diameter section 16b of the flow diversion structure 16 is aligned with the rearward most end of the second constant diameter section 2c of the outer casing 2. Each handle 24, 25 abuts a forward most end of each elongate aperture, thereby delimiting the first position. Applying a rearward axial force to the handles 24, 25 in an aft direction of the engine effects a movement towards a second, rearward, position of the flow diversion structure.

In the second, or rearward position of the flow diversion structure 16 within the outer casing 2, as shown in Figure 2, the flow diversion structure 16 is arranged rearward relative to the first position, wherein the second frusto-conical section 16b of the flow diversion structure 16 is spaced further rearward from the second frusto-conical section 2d of the outer casing 2 in the first position than in the second position. The second position is delimited by each of the handles 24, 25 abutting a rearward most end of each elongate aperture.

Applying a forward axial force to the handles 24, 25 effects a movement of the flow diversion structure 16 toward the first position.

The forward/rearward force may be applied to the handles 24, 25 manually or by any conventional actuation means.

The arrangement of the flow diversion structure 16 in the first and second positions, in combination with the arrangement of the burners 20, 21 within the outer casing 2, is such that the burners 20, 21 remain within the combustion chambers 3, in both the first and second positions.

When in the first position, the engine operates in use according to principles well known in the art.

The impeller fan 10 is rotated in the first direction, which draws air into the front end region 4 of the engine and forces air aft or rearward of the impeller 10 along the radial passage that is created between the flow diversion structure 16 and the outer casing 2. The air undergoes a first stage compression as it moves between the impeller fan 10 and the rearward most end of the first frusto-conical section 2a of the flow diversion structure 2. The first stage compression is due to the reduction in the cross sectional area of the passage. As the impeller fan 10 continues to rotate, the air is forced further aft along the passage. A second stage compression is effected as the air moves between the forward most and rearward most ends of the second frusto-conical section 2d of the flow diversion structure 2.

The compressed air is forced further aft, into the combustion chamber 3, wherein the air is mixed with fuel and ignited by the burners 20, 21. The expanding air is exhausted from the second end of the flow diversion structure 16 and, due to a path of least resistance, is exhausted through the turbine 12 and from the trailing end region of the engine. Exhausting air through the turbine 12 turns the turbine in the first direction.

The rotating axle 8 can be connected through an infinitely variable gearbox to the wheels of a vehicle.

Alternatively and/or additionally, the axle 8 may be connected to the stator of an electric motor for generating electricity.

During use, when the flow diversion structure 16 is moved toward thesecond position, the second stage compression between the outer casing 2 and the flow diversion structure 16 is increased due to the cross sectional area of the passageway decreasing. The increased second stage compression increases the speed at which the turbine 12 rotates due to the increased energy of the expanding air. The rotation of the turbine 12 is also increased due to reduced diffusion in the radial passage aft of the second end region of the flow diversion structure 16. The reduced dispersion occurs due to the space between the second end of the flow diversion structure and the forward most end of the diverging section of the turbine 12 being reduced in the second position when compared to the same space when in the first position.

The jet engine further comprises an auxiliary rotation means for rotating the turbine 12, which is independent of the airflow through the engine. The auxiliary rotation means comprises a two-stage flash steam boiler, which is arranged within the flow diversion structure 16 at the second end which comprises the combustion chamber 3.

The flash stream boiler comprises first 28 and second compartments, which, as shown in the figures, are a bottom 28 and top 30 compartment respectively. The outer wall of the flow diversion structure 16 bounds an outer circumference of the compartments 28, 30. As seen in Figure 3, the bottom compartment 28 is further bounded by a first wall 32, which extends horizontally the length of the second constant diameter section 16d of the flow diversion structure 16. The top compartment 30 is bounded horizontally by a second wall 34, which also extends the length of the second constant diameter section 16d of the flow diversion structure 16.

The first and second horizontal walls 32, 34 are parallel and vertically spaced apart, as shown in the Figure 3. The gap or spacing between the two walls 32, 34 enables the axle 8 to rotate freely there between within the space. The compartments 28, 30 are enclosed by front and rear, vertical end walls.

The forward most end region of the compartments 28, 30 include first 36 and second 38 interconnection passages.

Each interconnection passage is formed by a circular tube 36, 38 that extends between the upper and lower walls respectively of the compartments 28, 30. The tubes 36, 38 are coincident with holes in the top and bottom walls such that fluid can move between the two compartments 28, 30.

The passages 36, 38 are arranged either side of the axle 8.

A fluid injection means is arranged in the bottom compartment 28 and comprises a passageway 40 that extends into the compartment 28, such that fluid can be injected into the compartment 28. A first, outer, end of the tube extends through an aperture in the rearward most end wall of the lower compartment 28. The tube 40 is in a gaseously sealed arrangement with the aperture. The first end of the tube 40 is straight and of such a length that the tube remains sealed within the aperture when the flow diversion structure 16 moves between, and is arranged in, the first and second positions. The first end of the tube includes an aperture, which remains inside the compartment in both positions of the flow diversion structure 16. The cross sectional area of the aperture is smaller than the cross sectional area of each interconnection passage 36, 38.

The tube 40 is secured fast to the outer casing 2 by a second end 42 of the tube 40 that is bent at ninety degrees to the first end and attached to the outer casing 2. A supply line 44 supplies the tube with fluid, such as water.

The top compartment 30 includes a first fluid exit conduit 46 and a second fluid exit conduit 48. Each fluid exit conduit 46, 48 comprises a first inlet aperture arranged inside the top compartment 30 and a pair of outlet fluid apertures arranged adjacent the turbine 12.

It will be realised that there may be additional outlets provided. For example, the engine may comprise 4 outlet fluid apertures adjacent the turbine 12.

The fluid exit conduits 46, 48 further comprises a straight tubular first end. An inner distal end of the first straight tubular section includes the first aperture and extends into the top compartment 30 through an aperture in the rearward most end wall. The cross- sectional area of the inlet aperture is larger than the cross-sectional area of each interconnecting passage 36, 38. The distal end of each fluid exit conduit 46, 48 is connected to a radial plate that extends between the inside walls of the top compartment. The plate is in sealing arrangement with the compartment walls. The plate includes holes that are coincident with the first inlet aperture of each fluid exit conduit. The radial plate is arranged such that it remains within the compartment in both the first and second positions.

Each fluid exit conduit 46, 48 comprises a second end that formed into a forked tube, which splits each single passage 46,48 into two passages. A distal end of each fork includes the second and third exit apertures respectively and are arranged adjacent the turbine 12.

Each fluid exit conduit 46,48 is held securely to the outer casing 2 by a support bracket which extends across the outer casing 2 and is secured at either end to the internal walls of the outside casing. The bracket is arranged in the radial passage aft of the second end region of the flow structure 16 when in the second position.

When the flow diversion structure is moved between the first and second positions, the structure 16 moves relative to the injection tube 40 and each fluid exit conduit 46, 48. During such movement, the injection 40 and exit tubes 46, 48 do not hinder said movement. The radial plate connected to each fluid exit conduit also remains in sealing arrangement with the inside walls of the upper compartment 30 at all times. The upper compartment therefore has a reduced volume when in the second position when compared to the first position.

When in use, water or other evaporable fluids can be injected into the bottom compartment 28 through the fluid injection tube 40. Residual heat from the burners heats the injected water rapidly turning it into steam. As the water is heated, evaporating gas escapes the bottom compartment 28 through the interconnection passages 36,38 into the top compartment 30. The gas moves into the top compartment 30 due to a path of least resistance created by the interconnection passages 36,38 being larger than the injection aperture.

The resulting gas or steam is further heated when in the top compartment 30 due to the residual heat from the burners arranged adjacent the top compartment 30. The heated steam escapes the top compartment 30, due again to a path of least resistance, along the fluid exit conduits 46,48. The steam is exhausted out of the exit apertures arranged adjacent the turbine 12. The release of the heated steam from the apertures effects or assists a rotation of the turbine 12 in the first direction.

When moving the flow diversion structure 16 from the first position toward the second position, the volume of the top compartment 30 is reduced due to the relative movement of the radial plate and compartment walls. The decreased volume generates a greater secondary increase in the pressure of the steam and thus applies a greater force on the turbine 12 blades.

The flash steam boiler can be used to initiate the rotation of the axle 8 in order to force air along the fluid passage and or additionally can be used to enhance the forces acting to turn the turbine.

Figure 4 shows the second preferred embodiment of the present invention which, unless otherwise indicated, includes like parts to the first embodiment.

In the second embodiment, the flow diversion structure 116 which is formed of first and second relatively moveable parts l].6a, 116b in which the combustion chamber 103 is formed there-between. The rear section 116b also comprises the frusto-conical diverging section 101 of the turbine fan 12.

The rear section 116b of the diversion structure 116 is fixed in position so that the rear frusto-conical section diverts fluid flow to the blades of the turbine 12. The forward section 116a of the diversion structure is moveable forward and rearward as in the first preferred embodiment. The combustion chamber 103 is formed between the first and second section 116a, 116b of the diversion structure 116 such that the volume of the combustion chamber may be adjusted by movement of the first section 116a.

Advantageously, the combination of the frusto-conical section and the rear section 116b of the diversion structure prevent an increase in volume at a rear of the engine which reduces fluid velocity through the engine.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification

(including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features

disclosed in this specification (including any

accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claim5 1. A jet engine, comprising: at least one inlet and at least one

outlet; at least one fluid passageway arranged between the at least one inlet and the at least one outlet; fluid heating means arranged to heat fluid within the fluid passageway; and passageway control means for selectively controlling a cross sectional area of a section of the at least one fluid passageway.
2. The jet engine as claimed in claim 1, wherein the passageway comprises a fluid compression section and the fluid compression section is arranged, in use, upstream of a combustion section wherein said fluid heating means is arranged.
3. The jet engine as claimed in claim 2, wherein the fluid compression section comprises an annular fluid passageway and the cross-sectional area of the annular fluid passageway is variable.
4. The jet engine as claimed in claim 3, wherein the passageway control means is at least one section of the fluid passageway having a variable cross section.
5. The jet engine as claimed in any preceding claim, wherein the cross sectional area of the fluid passageway is controllable by a user.
6. The jet engine as claimed in any preceding claim, wherein the passageway control means comprises a flow diversion structure within the fluid passageway operable to control a cross sectional area of the at least one section of the fluid passageway between the at least one inlet and the at least one outlet.
7. The jet engine as claimed in claim 6, wherein the flow diversion structure is moveable within the fluid passageway, such that the cross sectional area of the at least one section of the fluid passageway can be varied.
8. The jet engine as claimed in claim 7, wherein the flow diversion structure is longitudinally moveable between a first position and a second position.
9. The jet engine as claimed in any of claims 6 to 8, wherein the flow diversion structure is be formed of first and second relatively moveable parts.
10. The jet engine as claimed in claim 9, wherein the second section is statically arranged rearward of the first section.
11. The jet engine as claimed in claim 10, wherein the first section is rnoveable so as to control the cross sectional area of the fluid passageway.
12. The jet engine as claimed in any preceding claim, comprising: an impeller fan arranged at a front region of the engine to draw ambient fluid into the fluid passageway; a drive shaft extending longitudinally through the engine, wherein the impeller fan is co-operable with the drive shaft, such that rotation of the drive shaft causes rotation of the impeller fan; and a turbine fan arranged at a rear region of the engine to be co-operable with the drive shaft.
13. The jet engine as claimed in claim 12, wherein, in a first position, the flow diversion structure is arranged toward the impeller fan.
14. The jet engine as claimed in any preceding claim, wherein the fluid heating means comprises at least one combustion region within the fluid passageway.
15. The jet engine as claimed in claim 14, wherein the fluid heating means comprises at least one burner arranged within the combustion region.
16. The jet engine as claimed in claims 14 or 15, wherein the combustion region is arranged in an outer periphery of the fluid passageway between the flow diversion structure and the outer perimeter of the fluid passageway.
17. The jet engine as claimed in claim 12, comprising second fluid heating means for heating a fluid introduced to an intermediate region of the jet engine, such that heated fluid is directed toward the turbine fan.
18. The jet engine as claimed in claim 17, wherein the second fluid heating means is arranged within the flow diversion structure.
19. The jet engine as claimed in claims 17 or 18, wherein the second fluid heating means is arranged within the portion of the fluid diversion structure inwardly adjacent to the combustion region.
20. The jet engine as claimed in any of claims 17 to 19, wherein the second fluid heating means comprises first and second chambers in fluid communication.
21. The jet engine as claimed in claims 17 to 20, wherein the second fluid heating means is a flash steam boiler.
22. The jet engine as claimed in claim 20 or 21, wherein the volume of the first and second chambers is responsive to the position of the flow diversion structure.
23. A method of operating a jet engine, comprising: inducing fluid into the engine; communicating the fluid through at least one fluid passageway; selectively controlling a cross-sectional area of a fluid compression section of the at least one fluid passageway; and heating the fluid within the passageway and exhausting heated fluid from the engine.
24. The method as claimed in claim 23, wherein the cross-sectional area of the fluid compression section is varied in use.
25. The method as claimed in claim 24, wherein the cross-sectional area of the fluid passageway prior to the heating means is varied.
26. The method as claimed in any of claims 24 or 25, wherein a longitudinal position of a flow diversion structure within the fluid passageway is adjusted.
27. The method as claimed in any of claims 23-26, wherein a second fluid is heated within the engine, such that heated fluid introduced to a middle region at of jet engine is directed toward a turbine fan.
28. A jet engine substantially as described hereinbefore with reference to the accompanying drawings.
29. A method of operating a jet engine substantially as described hereinbefore with reference to the accompanying drawings.