GB2517409A - An engine comprising a travelling wave magnetic field generator - Google Patents

Abstract

A petroleum derived fuel, e.g. natural gas/paraffin, is ignited in air within a hollow tubular body 2 and a resulting expanding conductive fluid ignition product is expelled from an outlet 8 of the hollow body 2 to produce thrust. The jet engine 1 uses a travelling wave magnetic field produced by a linear motor 11 to control the expansion of the fluid ignition product, accelerating the fluid ignition product, through acceleration zone 7, to produce thrust. The linear motor 11 comprises several magnetic field coils 12 axially spaced along the acceleration zone 7. The engine1 may include a second set of coils 13 downstream of the acceleration zone 7, which induce a current as the accelerated ignition product passes, the current being used to recharge the capacitor/battery 12A.

Description

An Engine Comnrising a Travelling Wave Magnetic Field Generator The present invention relates to a method in which a conducting fluid is controlled by a travelling wave magnetic field and ill particular an engine based on such a method.

Acceleration of a Conducting Fluid by a Traveling Magnetic Field' by Willis H. Braun describes the use of travelling magnetic wave accelerator which accelerates a conductiye fluid for the propulsion of interplanetary yehicles.

The accelerator works on a principle analogous to a linear motor. The accelerator comprises a tube surrounded by a series of coils through which an alternating current is fed. By controlling the current flow through the coils, a travelling magnetic wave can bc induced within thc tube. The magnctic wave acts upon a conducting fluid fcd into the tube, accelerating the fluid towards the other end of the tube.

In Experimental Investigation of A Constant-Velocity Travelillg Magnetic Wave Plasma Engine' by Robert E. Jones and other, the propellant is formed by firing electrons from an electron emitter into xenon gas in order to partially ionise it.

The Traveling-Wave Pump' by Eugene E. Covert aild other describes the use of such as system for power generation or wind tunnel propulsion. The plasma is generated in a manner similar to the aforementioned reference with the difference that helium is used as the propellant.

The following invention was conceived following discovery by the inventor that a flame is caused to be extinguished when placed near an electromagnet through which a current is passing.

According to a first aspect of the invention there is provided a method in which a fliel is ignited and the expanding fluid resulting from the ignition expelled to produce thrust, wherein a travelling wave magnetic field is used to control the expansion of the resulting expanding fluid.

Although not wishing to be bound to any particular theory, the inventor speculates the products of the ignition are or comprise an ionised or partially ionised gas which is affectable by a magnetic field. The invention provides a simpler method of forming the electrically conductive fluid over those previously known. It also enables an engine without moving parts.

In a preferred embodiment of the method gas comprising oxygen, favourably air, enters a hollow body, the flammable friel is ignited in the gas within the hollow body to form the conducting fluid and the travelling wave magnetic field controls the expansion of the conducting fluid towards an outlet of the hollow body. In order that the method is used to provide useful thrust, the gas may enter at or towards a first end of the body and the exhaust be accelerated towards a second end of the body.

The travelling wave magnetic field may be produced using a linear motor comprising one or more coils arranged such that when an alternating current is passed there-through, a corresponding magnetic wave is produced within the body which travels in a longitudinal direction with respect to the body.

Although a solid fuel may be used, in most practical applications a gas or liquid flammable fuel is preferred. Natural gas or petroleum derived fuels are thought particularly suitable.

The electrically conducting fluid may be directed past a circuit, e.g. through a further coil or coils, to induce, through electromagnetic induction, an electric current in the circuit. The induced current may be used to power the linear motor.

According to a second aspect of the invention there is provided an engine comprising a hollow body having an inlet through which a fluid can pass into the body, means to ignite a flammable fuel in the fluid to form an electrically conductive fluid and means to generate a travelling wave magnetic field to control the expansion of the electrically conductive fluid away from the inlet towards an outlet of the body.

The invention will now be described by way of example with reference to the Figure which is a schematic of an engine in which thrust is generated by igniting a fuel in air and accelerating the resulting conductive fluid using a travelling magnetic wave.

A jet engine 1 comprises a tubular body 2 having an outer casing 3 and a non-electrically conducting inner casing 4. The inner casing 4, which may be made from a ceramic material, is hollow and open at both ends to define a fluid pathway having an inlet 5 for air, a combustion zone 6, a zone in which the combustion products are accelerated 7 and an outlet 8.

Air that has passed through the intake 5 is mixed in the combustion zone 6 with a liquid petroleum derived fuel, e.g. paraflin, supplied via a fuel injector (shown schematically as 9) and the fuel/air mix ignited by an ignition system which may include a sparking means, e.g. a sparking plug 10.

The combustion product, being affectable by a magnetic field, is accelerated towards the outlet 8 by a linear motor 11 that comprises several magnetic field coils 12 each of which surround a portion the pathway such that combustion product must pass through the centre of the coils 12. The coils 12 are spaced axially along the acceleration zone 7.

The coils 12 arc connected to a multi-phase ale power supply 12A, which may be provided via a battery/capacitor and associated circuitry in order to create a travelling magnetic wave along the acceleration zone 7 in a manner which is well known to persons skilled in the art of linear motors.

In operation, the combustion product from the ignition in thc combustion zone is preferentially accelerated away towards the outlet 8, this causes more air to be drawn through the inlet 5 in which further fuel can be burnt.

The inner casing 3 and outer casing 4 are radially spaced apart to tbrm an annular bypasspassagel4thatextendsfromtheinlet5tothebackofthebody2. Whenthe engine is operating, air is drawn through the bypass passage 14 in order to provide cooling to the inner casing 3, coils 12, 13.

A second set of coils 13 are located towards the back of the engine, downstream of the accelerator zone 7. As with coils 12, they surround the pathway. As the accelerated ignition product passes along the pathway, through coils 13 they induce a current in the coils 13 and associated circuit 13A to recharge the capacitor/battery I 2A.

The engine may comprises a further coil 15 positioned upstream of coils for lbrming a steady magnetic field through which the accelerated ignition product passes before reaching coils 13. The steady magnetic field acts to separate the ions and electrons within the ignition product so that a net ion current results. The heavier ions are forced towards the centre of the stream of ignition product whereas the electrons are drawn radially outwards towards the inner wall of inner casing 4. Because the flow rate towards the centre of the stream is faster than at the edges of the stream a net ion current is produced which when passing through coils 13 induces a current therein.

The engine may comprises further coils (not shown) arranged to produce a steady magnetic field which extends from the combustion zone 6 to the outlet 8, to minimise the contact of the combustion products against the inner casing 4 to reduce energy loss caused by transfer of energy to the inner casing 4 as heat In a variation to the above, electrons can be introduced at the fuel injector so as to form electrostatiSly-charged droplets; these will improve the effectiveness of the magnetic fields. A high-voltage field will be rcquiitd and the positive electrode of the electrostatic circuit could be placed outsidc of the combustion chamber, with a collector plate inside. This arrangement will result in a further drag' fbrce on the electmns closest to the outer wall, increasing the net ion current and hence the efficiency of the generator.

The engine as a whole will tend to have a resonant frequency, which should result in the minimum energy loss possible. The engine may be fhrthcr provided with an anti-noise' circuit centred around that frequency will help to reduce the overall volume of the sound produced at the expense of optimum performance.

Claims (17)

1. Claims 1. A method in which a fuel is ignited and the expanding fluid resulting from the ignition expelled to produce thrust, wherein a travelling wave magnetic field is used to control the expansion of the resulting expanding fluid.
2. 2. A method according to claim I in which the travelling wave magnetic field is used to control the direction of expansion of the resulting expanded fluid.
3. 3. A method according to claim 1 or 2 wherein the flammable fuel is mixed in a gas comprising oxygen
4. 4. A method according to claim 3 wherein the flammable fuel is mixed in air.
5. 5. A method according to any previous claim wherein the flammable fuel is a hydrocarbon fuel.
6. 6. A method according to any previous claim wherein a linear motor causes acceleration of the expanded fluid.
7. 7. A method according to any previous claim wherein a gas enters a first end of a hollow body, the flammable fuel is mixed and ignited in the gas within the hollow body to form an electrically conducting expanding fluid and the travelling magnetic field controls the expansion of the resulting electrically conducting expanding fluid towards an outlet at a second end of the hollow body.
8. 8. A method according to claim 7 wherein the electrically conducting expanded fluid is directed past a circuit to induce, through electromagnetic induction, an electric current in the circuit.
9. 9. A method according to claim 8 wherein the clectrically conducting fluid passes through a steady magnetic and/or electrostatic field in order to separate ions and electrons within the conducting expanding fluid before the conducting expanded fluid passes the circuit.
10. 10. A method according to claim 8 or 9 wherein the current induced in the circuit is used to power the linear motor.
11. 11. Anengineusingthemethodofanyclaim 1-10.
12. 12. An engine comprising a hollow body having an inlet through which a fluid can pass into the body, means to ignite a flammable fuel in the fluid to form a electrically conductive fluid and means to generate a travelling wave magnetic field to control the expansion of the electrically conductive fluid away from the inlet towards an outlet of the body.
13. 13. An engine according to claim 12 comprising means to cause a current to pass through one or more coils which surround the body so as to induce alongitudinally travelling magnetic wave field.
14. 14. An engine according to claim 12 or 13 comprising an outer casing which is radially spaced from the hollow body to form a bypass channel through which fluid can flow to cool the hollow body
15. 15. An engine according to any claim 12-14 wherein the electrically conductive fluidisarntngedtopassacircuitsoastoinduccacurrentwithinsaidcfrcuit
16. 16. An engine according to claim 15 comprising means to generate a steady magnetic and/or electrostatic field through which the electrically conductive fluid is directed before passing the circuit.
17. 17. A method in which a conducting fluid is accclcrated with a travelling magnetic field to generate thrust, wherein a flammable fuel is ignited in a gas comprising oxygen to create the conducting fluid.