GB2414292A

GB2414292A - Rotating Fuel Mixing Arrangement for Combustion Fluids of a Jet Engine

Info

Publication number: GB2414292A
Application number: GB0510704A
Authority: GB
Inventors: Ian Stephen Bell
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-05-26
Filing date: 2005-05-26
Publication date: 2005-11-23
Also published as: GB0510704D0

Abstract

A fluid and fuel mixing system has a chamber (34 fig 1) through which a fluid can pass and in which fuel 36 can be held. The fuel is rotated by a drive arrangement when it is held within the chamber, the rotation influencing the shape and/or position and/or characteristics of the fuel. The system has an entry conduit 30 for directing the fluid into the chamber, an exit conduit 42 for directing a mixture of fuel and fluid out of the chamber, and a restrictive passageway 40 within the chamber through which the fluid passes. The restrictive passageway is bounded in part by the fuel surface 38, and causes the pressure and/or temperature of the fluid to increase as it passes through the passageway; the fluid engaging with the fuel surface. During operation of the system in a jet engine, it may be located between an air duct 2 and an engine combustion space 6, and may also include an air baffle 18. The chamber may form an annular trough 16 within a mid portion 4 of the engine, and may rotate about a longitudinal axis 14 on bearings 8. Airflow through the passageway generates and mixes with vaporised fuel, the mixture burning in the engine combustion space to produce propulsion. Alternatively the chamber may be static (40 fig 10) and the fuel caused to rotate by a rotating fluid stream.

Description

24 1 4292 An Air and Fuel Mxmg Device For A Jet Engme and A Jet Engme The

present Invention relates to a fluid and fuel mxmg device for an engme and m particular, to an air and liquid fuel mung device for an engme, and more m particular, to aJet engine t'or an aircraft.

The basic design of a let engme is well known. The design consists of a tubular body having an entrance and exit. Air enters the engine through the entrance and Is then compressed, mixed with fuel, gmted and then expelled under pressure through the exit m the form of an exhaust gas to generate the propulsive force on the engmc. The flow, mcludmg compresson/expansion of the air, the ar/fuel mixture and the exhaust gas Is control by the geometry of the tubular body and Is typically assisted by turbines. The fuel Is typically mixed with the air passmg through the engme by being Injected mto the airflow as it passes through the tubular body. This requires the use of Injectors.

The present Invention Is intended to provide an alternative design for the mechanism by which the fuel Is combined with the air passing through aJet engine.

GB370487 discloses a mechanism by which a mixture of vapoursed fuel and air Is created for use In an internal combustion engme. The mechamsm operates by the rotating liquid fuel around a circular path formed on an Inner wall of a chamber. 'I'he fuel sticks to the path due to centrifugal forces. Air enters the chamber under pressure In a direction which causes it to rotate around the circular path. As fuel Is pumped Into the chamber, it Is entrained by the flow of air causing it to circulate around the path. The fuel Is vapounsed by the faction between the air and the fuel as they circulate. However, the mechanism described m GB370487 is unsuitable for use m a Jet engme to provide a vapoursed fuel and air mixture for combustion.

Accordingly there Is provided a fluid and fuel mxmg system for aJet engme compnsmg: a chamber through which a fluid can pass and in which fuel can be held; a rotational drive to rotate the fuel when it is held rhythm the chamber; the fuel, when rotationally held In the chamber, having at least one surface within the chamber, the shape and/or position and/or characteristics of which are dependent upon the rotational movement of the fluid; an entry vent for drectmg the fluid into the chamber; ' '. it, an exit vent for drectmg a mixture of fluid and fuel out of the chamber; '. ' i 1 it.

a restrictive passageway formed withy the chamber through which the fluid passes when it passes through the chamber, the restrictive passageway causing the pressure and/or temperature of the fluid to Increase as it passes through the passageway; wherein, when the fuel Is rotationally held in the chamber, the restnctve passageway Is bounded In part by the surface of the fuel, the fluid engaging with the surface of the fuel when it passes through the passage way.

Four embodiments of the mventon will now be described with reference to accompanying drawings of which: Figure I shows a sketch of a vertical cross section of a jet engme according to the first embodiment of the invention with no fuel withm the torodal chamber; Figure 2 shows a sketch of a vertical cross section of the jet engme with fuel within the torodal chamber but with no air passmg through the chamber; Figure 3 shows a sketch of a vertical cross section of the jet engine as Indicated by Arrows A in figure 2; Figure 4 shows a sketch of a vertical cross section of the Jet engine with fuel within the torodal chamber and with air passmg through the chamber; Figure 5 shows a sketch of a vertical cross section of a part of the middle section when rotated at different speeds; Figure 6 shows a sketch of a vertical cross section of a part of the middle section with different amounts of fuel within the torodal chamber; Figure 7 shows the air baffle according to the second embodiment of the present mventon with a spiral vane; Figure 8 shows a sketch of a vertical cross section of the second embodiment of the Jet engine with fuel withy the Coronal chamber and with air passmg through the chamber; Figure 9 shows a sketch of a horizontal cross section of a Jet engine as medicated by Arrows (a In Figure 2; Figure 10 shows a sketch of a vertical cross section of a Jet engme according to the third embodiment of the invention with fuel withy the toroidal chamber and with air passing through the chamber; and figure 11 shows a sketch of a vertical cross section of a Jet engme according to the fourth embodiment of the mventon with fuel within the toroidal chamber and with air passing through the chamber.

Figure I shows the Jet engme according to the first embodiment of the present Invention without any hquid fuel located withm it.

Referrmg to figure 1, the jet engme comprises an outer housing having three sections; a forward section 2, a middle rotatable section 4 and a rear section 6. The front (forward end) of the engine Is on the right as shown m E'gure 1. All three sections 2; 4; 6 are circular In cross section along their lengths. However, the diameters of each of the sections 2; 4; 6 alter along their length as shown m Figure 1.

The forward section 2 and the rear section 6 are held stationary. The middle rotatable section 4 is mounted on the forward section 2 via a first set of bearings 8 and Is mounted on the rear section 6 via a second set of bearings 10. The middle rotatable section 4 can rotate about the longitudinal axis 14 of the let engme on the bearings 8; 10 but Is prevented from sliding axially backwards and forwards. Seals (not shown) are provided adjacent the beanug 8; 10 so that gases within the engme can not leave a chamber formed by the forward, middle and rear sections 2; 4; 6 via the gaps between adjacent sections 2; 4; 6.

The shape of the middle rotatable section 4 is that of an annular trough 16, the opening of which faces radially Inwards towards the longitudinal axis 14. 'I'he middle rotatable section 4 Is rotationally driven via motor (not shown). When the jet engine is m use, the motor rotates the middle rotatable section 4 at prcdetermned rotational speeds which are capable of bemg adjusted to suite the particular situation.

Located withy middle rotatable section symmetrically about the longitudinal axis 14 of the engme, is an air baffle 18. The air baffle 18 Is circular m cross section along its length.

However, the diameter of the air baffle 18 alters along its length as shown m Figure 1. The nose 20 of the air baffle 18 projects mto a space 22 surrounded by the front section 2. The air baffle 18 also has a tall 24 which projects mto a space 44csurrounded by the rear section 6.

Struts (not shown) support the air bame and hold it stationary rhythm the engine.

A Coronal chamber 34 Is formed by the mner wall 26 of the annular trough and the central part 28 of the outer wall of the air baffle 18. A vent 30 is formed between nose 20 of the air baffle 18 and the leading edge wall 32 of the middle rotatable section 4 through which air can enter the torodal chamber 34.

Figure 2 shows the jet engine with liquid fuel 36 located withm it (but with no air passmg through the engine).

Referring to Figure 2, in use, the middle rotatable section 4 Is rotatmgly driven by the motor.

The hound fuel 36 Is fed mto the annular trough 16. As the middle rotatable section 4 Is rotating, it causes the liquid fuel 36 to rotate with it. As the hqud fuel 36 Is rotating, it Is forced radially outwardly, away from the longitudinal axis 14 of the engme, against the base of the annular trough 16 due to centrifugal forces, as best seen In Figure 3. A surface 38 Is formed on the fuel 36 which faces radially Inwardly towards the longitudinal axis 14 of the jet engme. A small gap 46 Is formed between the surface 38 of the liquid fuel and the air baMe 18. The gap 46 results In a passageway 40 bemg created wthm the torodal chamber 34 which allows air to pass between the front section 2 and the rear section 6.

The mechanism by which fuel is fed mto the annular trough 16 has not be shown as there are many ways by which fuel can be fed mto the annular trough 16 which will be readily appreciated by the an engineer. For example, the fuel could be squirted radially outwardly from the air baMe 18, In which it can be stored, Into the annular trough 16. Heat from the operation of the engine can be used to generate a pressure to act on the fuel whom the air baffle 18 to force it our of the baffle and squirt it Into the annular trough 16.

The speed of rotation of the middle rotatable section 4 and the hqud fuel 36 can be made to be sufficiently fast that the effects of gravity on the position liquid fuel 36, and hence the position of the surface 38, withm the annular trough 16 are negligent.

A second vent 42 Is formed between the tall 24 of the air baffle 18 and part of the rear wall of the annular trough 16 and/or the surface 38 of the Squid fuel 36 (depending on the position of the surface 38) through which a mixture of air and vapoursed fuel Is able to exit the torodal chamber 34.

When the middle rotatable section 4 Is rotating but no air Is passmg through the engine, the surface 38 of the liquid fuel remains substantially flat as shown m Figure 2. The gap 46 between the surface 38 of the hquid fuel 36 and the air baMe 18 remams relatively small.

However, when the Jet engine Is runmng and moving forward (right In Figures I, 2 and 4), air enters the jet engine and passes mto the forward section 2 of the outer housing. Figure 4 shows the jet engine with hound fuel 36 located rhythm it and with air passing through the engine.

The airflow (indicated by the Arrows B m Figure 4) engages with the nose 20 of the air baffle 18 where Is directed radially outwardly as it passes through the forward section 2 Into the chamber 34 formed by the middle rotatable section 4 and the air baMe 18 via the vent 30. At this point, the air passes through the chamber 34 by passmg through the passageway 40 formed by the gap 46 between the surface 38 of the Squid fuel 36 and the air baffle 18 and then exits through the second vent 42 Into the rear section 6 of the outer housing.

As the air passes through the passageway 40, it Is compressed due to the resection caused by the narrowness of the gap 46. This Increases pressure and temperature of the air as it passes through the passageway 40. Vapour, generated from the liquid fuel 36 by the compressed air passing over the surface 38 of the liquid fuel 36 as it passes through the passageway 40, emanates from the surface 38 and mixes with the air passing through the passageway 40. The mixture of air and vapounsed fuel then passes through the vent 42 Into the rear section 6.

The mixture of air and gaseous fuel may commence burning automatically as it passes through the second vent 42 and Into the rear section, If the gaseous mixture Is at the appropriate temperatures and pressures. Alternatively, an igniter (not shown) can be located either m the second vent 42 or the rear section 6 to start the combustion process of the air and vapounsed fuel mixture.

The centrifugal forces acting on the rotating fuel 36 will seek to keep the surface 38 of the liquid fuel 36 flat, as shown m figure 2. However, due to the pressure of the air passing through the passageway 40, the surface 38 will become displaced, as best shown In Figure 5, as the hqud fuel 36 Is caused to move against the centrifugal force acting upon it. As such the gap 46 widens. In order to reduce the width of the gap 46 (whilst mantamng the same volume of fuel 36 withy the annular trough 16), the rate of rotation of the middle rotatable section 4 and Squid fuel 36 can be Increased. This will increase the centrifugal forces actmg on the hquid fuel 36 which will reduce the effects of the pressure of the air passmg through the passageway 40 on the surface 38, thus resulting m the surface 38 becoming flatter and the gap 46 becoming smaller, as Indicated by the dashed hue 48 in Figure 5.

Therefore, by controlhng the rate of rotation of the middle rotatable section 4, and hence the liquid fuel 36, the size of the gap 46 can be controlled. By controlling the size of the gap 46, the temperature and pressure of the air passing through the passageway 40 can be controlled.

This will m turn control how much liquid fuel 36 Is vapourised and mixed with the air, and whether the appropriate temperatures and pressures are met for automatic combustion of the gaseous air and fuel mixture. Furthermore, the size of the centrifugal forces actmg on the rotating hound fuel 36 may effect the vapounsmg process of the fuel from the surface 38 due to the pressures acting on the surface 38. The size of the centrifugal forces actmg on the fuel are kept at a level which prevents the fuel from simply bemg blown out of the chamber 34 and Bantam a surface 38 on the fuel 36 to create and mamtam the passageway 40, particularly when the pressure and temperature of the air m the passageway 40 increases.

The size of the gap 46 can also be controlled m a second manner. The size of the gap is also dependent on the amount of Aqua fuel 36 located wthm the annular trough 16. By mcreasmg (educated by the dashed hue 50 m Figure 6) or decreasing (indicated by the dashed line 52 m Figure 6) the volume of Squid fuel 36, the size of the gap 46 can be altered. This will provide further control as the rate of rotation of the middle rotatable section 4 and Squid fuel 36 can be held fixed whilst the size of the gap 46 Is altered.

It will be appreciated that sufficient hquid fuel 36 could be introduced mto the annular trough 16 so that there Is no gap 46 until air commences passing through the engine m order to create agap46.

Furthermore, an increase or decrease m the rate rotation can be used to reduce or counteract the effect on the increase or reduction of the liquid fuel on the position of the surface 38 of the fuel 36 (and hence the size of the gap 46); its increase being caused by the addition of Squid fuel at a rate greater than that at which it Is being vapounsed; its decrease bemg caused either because no fuel Is bemg added or by the addition of liquid fuel 36 at a rate less than that at which it is being vapourised.

Such control may be useful m a small version of such a jet engme, for example, for use with a small model plane. In such an engine, it may be dfUcult to construct a system of addmg fuel 36 to the annular trough 16. Therefore, all the fuel 36 which Is to be used Is located within the trough 16 prior to the engine being used. As the engme Is operated, the fuel 36 m annular trough 16 Is utlsed to power it. Once the annular trough 16 Is empty, the engine will cease to work. Whilst the engme Is running, the rate of rotation can be altered to mamtam the passageway 40 at appropriate dimensions, counteracting the effect the fuel 36 being used.

As the engme accelerates m a forward direction, the forces which due to the acceleration could change of profile of the surface 38 of the liquid fuel 36 which m turn alter the dimensions of the passageway 40. This can be counteracted by rotating the liquid fuel 36 at a sufficient rate that the effects on the surface 38 due to the acceleration are minimal.

Alternatively, the shape of the air baffle 18 and middle section could be arranged to accommodate this effect.

A second embodiment of the Invention will now be described with reference to Figures 7, 8 and 9. The second embodiment Is similar to the t'irst embodiment. Where the same features are present m the second embodiment as m the first, the same reference numbers have been used.

The difference between the first and the second embodiments Is that spiral vanes 54 has been added to the nose 20 of the air baMe. In the first embodiment of the present mventon, the air passes over the surface 38 of the hqud fuel 36 m a direction (indicated by Arrow D m Figure 9) which Is perpendicular to the direction of travel of the surface 38 of the fuel 36 due to its rotation (see Arrow F m Figure 9).'1'he addition of a spiral vane 54 causes the air to rotate in a direction indicated by the Arrow C m Figure 7. This results m the air passing over the surface 38 of the Squid fuel 36 m a non perpendicular direction (indicated by Arrow E m Figure 9) to the direction of Gavel of the surface 38 of the fuel 36 due to its rotation. This has the effect of decreasing the relative speed of the air passing over the surface 38 of the liquid fuel 36.

Furthermore, the air will travel a greater distance over the surface 38 of the fuel 36 whilst traversing it. Therefore, by drectmg the direction of travel of the air over the surface 38, amongst other things, the vapounsmg charactenstcs of the engme can be altered. It will be appreciated that the spiral vane 54 could be arranged to spiral m the opposite direction, thus causing the relative speed of the air over the surface 38 of the fuel 36 to increase.

Furthermore, with adjustable vanes, the direction of travel can be altered whilst the engine Is running.

A third embodiment of the Invention will now be described with reference to Figure l O. The third embodiment Is similar to the second embodiment. Where the same features are present In the third embodiment as In the second, the same reference numbers have been used.

In the third embodiment, the front 2, middle 4 and rear 6 section are contracted m a one piece construction so that the middle section 4 Is prevented rotation. This results m the annular trough 16 remammg stationary. The liquid fuel 36 rotates rhythm the trough 16. The rotation of the fuel 36 Is caused by the air passmg over the surface 38 of the fuel 36 In a non perpendicular direction due to the spiral vane 54. As the air passes over the surface 38, it makes a frictional contact with the surface 38, urging it to move. The direction of travel of the fuel 36 Is controlled by the annular trough 16.

A spiral profile 56 can be formed on the base of the annular trough 16 to assist In drectmg the movement of the fuel In an axial direction as it rotates, as shown m Figure 10. Though the peaks of the spiral profile 56 are shown located below the surface 38 of the fuel 36, it will be appreciated that they extend inwardly sufficiently to penetrate the surface 38 and project mto the passageway 40 which is bounded m part by the surface 3 8.

A fourth embodiment of the mventon will now be described with reference to Figure 11. The fourth embodiment is similar to the first embodiment. Where the same features are present m the fourth embodiment as In the first, the same reference numbers have been used.

The main difference between the fourth and the first embodiments Is that, In the fourth embodiment, the middle section 4 Is rotatmgly driven by air as Indicated by Arrows H passing the engme. The engine comprises an outer housing 60 which surrounds the engme. Fins 62 are rigidly attached to the outside of the middle section 4. The fins 62 are angled so that, as the air passes between the outside of the middle section 4 and the Inside of the outer housing 60, the fins 62, and hence the middle section 4, rotate.

A turbme 64 can be mounted on the front of air baffle 18 to push air mto the engine. A second turbme 66 can be mounted on the rear of the baffle 18 which Is rotationally driven by the exhaust gases created by the engine. The second turbine 66 can then be used to drive the first turbme 64.

Claims

Claims I A fluid and fuel mixmg system for aJet engme composing: a chamber

34 through which a fluid can pass and m which fuel 36 can be held; a rotational drive to rotate the fuel 36 when it Is held within the chamber 34; the fuel 36, when rotationally held m the chamber 34, having at least one surface 38 within the chamber 34, the shape and/or position and/or characteristics of which are dependent upon the rotational movement of the fluid 36; an entry vent 30 for directing the fluid into the chamber 34; an exit vent 42 for directing a mixture of fluid and fuel out of the chamber; a restrictive passageway 40 formed within the chamber 34 through which the fluid passes when it passes through the chamber 34, the restrictive passageway 40 causing the pressure and/or temperature of the fluid to increase as t passes through the passageway 40; wherein, when the fuel is rotationally held m the chamber 34, the restrictive passageway 40 Is bounded In part by the surface 38 of the fuel 36, the fluid engaging with the surface 38 of the fuel 36 when it passes through the passage way 40.
2 A fluid and fuel mixing system as claimed m claim I wherem the fluid Is a gas.
3 A fluid and fuel moms system as claimed In either of claims I or 2 wherem the fluid IS air.
4 A fluid and fuel mixing system as claimed in any one of the previous claims wherem the fuel Is at least In part vapoursed when it exits the 4 chamber 34.
A fuel mixing system as claimed m any one of the previous claims wherein at least part of the profile of the passageway 40 Is determined In part by the shape and/or position of the surface 38 of the fuel 36 withy the passageway.
6 A fluid and fuel mxmg system as claimed m any one of the previous claims wherem the profile of the passageway 40 can be adjusted either In the lengthwise direction or In the cross sectional shape, or a combmaton of the two.
7 A fluid and fuel mxmg system as claimed in any one of the previous claims wherein the size of the entrance to the exit vent 42 Is determined by the shape and/or position of the surface 38 ofthe fuel 36 whom the chamber 34.

8 A fluid and fuel mxmg system as claimed in any one of the previous claims wherein restrictive passage way 40 Is formed by the surface 38 of the fuel 36 and at least one wall 28 of the chamber 34.
8 A fluid and fuel mixing system as claimed m any one of the previous claims wherem the fuel Is rotated about an axis 14 of rotation In order to alter and/or control the position and/or the profile and/or the characteristics of surface 38 of the fuel 36.
9 A fluid and fuel mixing system as claimed In claim 8 wherem the fuel 36 Is rotated about the axis 14 of rotation at a sufficient rate that the surface 38 of the fuel 36 substantially faces towards the axis 14 of rotation due to centrifugal forces.
A fluid and fuel mixing system as claimed In any one of the previous claims wherem the rate of rotation of the fuel 36 Is such that the surface 38 of the fuel 36 Is prevented from disintegrating as the fluid passes through the passageway 40.
11 A fluid and fuel mixing system as claimed In any one of the previous claims wherein the fuel 36 Is held within a portion 16 of the chamber due to centrifugal forces.
12 A fluid and fuel mixing system as claimed in claim 11 wherein the portion 16 of the chamber 34 in which the fuel 36 Is held Is capable of being rotated by the rotational drive about the axis 14 of rotation.
13 A fluid and fuel mixing system as claimed m either of claims 11 or 12 wherein the portion of the chamber 34 In the fuel 36 Is held by the centrifugal forces In an annular trough 16.
14 A fluid and fuel mixing system as claimed In claim 13 wherein the base on the annular trough 16 comprises a spiral profile 56.
A fluid and fuel mixing system as claimed In any one of the previous claims wherem the part of the profile of the passageway 40 which Is determined by the shape and/or position of the surface 38 of the fuel 36 which bounds the passageway 40, can be adjusted either In the lengthwise direction or In the cross sectional shape, or a combmaton of the two by altering the rate of rotation of the fuel 36.
16 A fluid and fuel mixing system as claimed m any one of the previous claims wherein the part of the profile of the passageway 40 which Is determined by the shape and/or position of the surface 38 of the fuel which bounds the passageway 40, can be adjusted either In the lengthwise direction or m the cross sectional shape, or a combmaton of the two, by altering the volume of fuel 36 rhythm the chamber 34.
17 A fluid and fuel mixing system as claimed In any one of the previous claims wherem the part of the profile of the passageway 40 which Is determined by the shape and/or position of the surface 38 of the fuel 36 which bounds the passageway 40, can be substantially maintained in shape and/or profile either In the lengthwise direction or In the cross sectional shape, or a combination of the two, when the volume of fuel 36 within the chamber 34 changes by adjusting the rate of rotation of the fuel 34.
18 A fluid and fuel mixing system as claimed in any one of the previous claims wherem the part of the profile of the passageway 40 which Is determined by the shape and/or position of the surface 38 of the fuel 36 which bounds the passageway 40, can be substantially mamtaned m shape and/or profile either m the lengthwise direction or m the cross sectional shape, or a combination of the two, when the volume of fuel 36 withy the chamber 34 increases by decreasing the rate of rotation of the fuel 34.
19 A fluid and fuel mixing system as claimed m any one of the previous claims wherem the part of the profile of the passageway 40 which Is determined by the shape and/or position of the surface 38 of the fuel 36 which bounds the passageway 40, can be substantially maintained m shape and/or profile either m the lengthwise direction or m the cross sectional shape, or a combination of the two, when the volume of fuel 36 within the chamber 34 decreases by mcreasmg the rate of rotation of the fuel 34.
A fluid and fuel mixmg system as claimed m any one of the previous claims wherein the direction of travel of the fluid across the surface 38 of the fuel 36 is substantially perpendicular to the direction of travel of the fuel 36 due to its rotation.
21 A fluid and fuel mxmg system as claimed in any one of claims I to 19 wherein the direction of travel of the fluid across the surface 38 of the fuel 36 Is non perpendicular to the direct of travel of the fuel 36 due to its rotation.
22 A fluid and fuel mxmg system as claimed m claim 21 wherein the movement of the fluid across the surface 38 of the fuel 36 causes the fuel 36 to rotate.
23 A Jet engme comprsmg a fluid and fuel mixing system as claimed m any one of the previous claims.
24 AJet engme as claimed m claim 23 wherein there Is further at least one turbine 64; 66 to assist the movement the fluid through the engine.

A Jet engine as claimed In either of claims 23 or 24 wherein the axis l 4 of rotation of the fuel Is parallel to or coaxial with the longitudinal axis 14 of the engine.