RU2764496C1 - Magnetoplasma electric jet engine - Google Patents

Abstract

FIELD: space technology.SUBSTANCE: invention relates to space technology, more precisely to electric jet engines, and can be used in spacecraft. The magnetoplasma electric jet engine contains a housing, at least one ring magnet and a radio frequency antenna connected to a radio frequency radiation generator, a working medium in the form of a wire and at least one coil for storing it, as well as guide elements and a wire feeder. Coils with a wire wound on them are placed on the outer surface of the housing on bearings and the axis of rotation of the coils is aligned with the axis of the engine, and the wire and coils are made of ferromagnetic materials, together magnetized before use in a direction parallel to the axis of the engine, and are used as permanent ring magnets, in this case, the wire feeder is made with the possibility of jointly feeding the wire from all the coils with an adjustable speed depending on the power of the radio frequency radiation.EFFECT: when using the invention, a decrease in the mass of the engine is ensured due to the performance of the working fluid also with the functions of a magnetic system.1 cl, 1 dwg

Description

The invention relates to space technology, more specifically to electric jet engines, and can be used in spacecraft.

Known plasma electric propulsion engines described in the literature (for example, Propulsion systems for spacecraft, part 2, Electric rocket engines and propulsion systems based on them, edited by Prof. V.V. Sinyavsky, St. Petersburg, VKA named after A.F. Mozhaisky, 2015, p. 131) include a working fluid, an ionizer and a charged particle accelerator, as a rule, with a magnetic system. As a working fluid, inert gases are mainly used - xenon, krypton, argon, as well as easily ionizable alkali metals - cesium, lithium, sodium.

It is also possible to use liquids or solids, for example, metals, including iron, as working bodies. Known, for example, a plasma engine on nanoparticles of metals or metalloids (patent RU 2534762 C1, IPC: F03H 1/00 (2006.01), publ. 10.12.2014, bull. No. 34).

The supply of a metal working fluid to the engine can be organized using different devices, in particular, as in the plasma torch according to the utility model RU 190460 U1, IPC: H05N 1/24 (2006.01), publ. 07/01/2019, bul. No. 19. It proposes a device for feeding consumable filler wire from a coil into an arc discharge chamber.

Closest to the proposed engine is a magnetoplasma electrodeless rocket engine VASIMR (US 6334302 Bl, F02K 99/00 (2006.01); F03H 1/00 (2006.01); H05 B 6/10 (2006.01); publ. 01.01.2002), adopted for prototype.

The engine contains a container for storing a gaseous or liquefied working fluid - argon, a device for supplying the working fluid, a radio frequency (RF) emitter for ionization of the working fluid and plasma formation, a second RF emitter designed for selective heating of the ion component of the plasma at the frequency of ion cyclotron resonance. . Each RF emitter is connected to its own RF generator, which converts DC energy into RF oscillation energy. In addition, the engine includes a magnetic system consisting of several coaxial ring magnets that form an axial magnetic field inside the engine and an expanding magnetic field (“magnetic nozzle”) at the exit of the engine. The axial magnetic field serves to keep the plasma near the axis of the engine and prevent its contact with the walls of the engine, and the "magnetic nozzle" serves to form the axial component of the velocity of charged particles - ions and electrons, and thus to create engine thrust. The described magnetoplasma engine is often also called a helicon engine, since the input of energy into the electronic component of the plasma and the ionization of the working fluid by the first RF emitter is carried out at one of the resonant frequencies of the natural oscillations of the magnetized plasma - helicons.

There are other designs with RF heating and a magnetic nozzle, for example US 6293090 B1, publ. 09/25/2001; WO 2013098505 A1, publ. July 4, 2013, RU 2330181 C2, published on July 27, 2008). The engine can use one RF emitter instead of two to inject energy only into the electronic component of the plasma. In this case, the ions are accelerated in the ambivalent electric field formed during the outflow of electrons. Such an engine is commonly called a mini-helicon.

The disadvantage of all these devices is the use of a magnetic system, the mass of which makes up the bulk of the mass of the engine, and which does not perform other functions than creating a magnetic field.

The objective of the invention is to eliminate this disadvantage.

The technical result of the invention is to reduce the mass of the engine due to the performance of the working fluid also functions of the magnetic system.

The technical result is achieved by the fact that in a magnetoplasma electric jet engine containing at least one ring magnet and a radio frequency antenna connected to a radio frequency radiation generator, the working fluid is in the form of a wire and at least one coil for storing it, as well as guide elements and a wire feeder , coils with wire wound on them are placed on the outer surface of the housing on bearings and the axis of rotation of the coils is aligned with the axis of the motor, and the wire and coils are made of ferromagnetic materials, jointly magnetized before use in a direction parallel to the motor axis, and used as permanent ring magnets wherein the wire feeder is configured to co-feed the wire from all spools at a controlled speed depending on the power of the radio frequency radiation.

The essence of the invention is illustrated by a constructive diagram.

The engine includes a ferromagnetic wire 1, guides 2, one or more coils 3 rotating with the help of bearings 4 around the housing 5, one or more RF antennas 6 and a wire feeder 7. All elements of the engine are mounted on the housing 5, which can be made in the form of a shell or a rod frame of non-magnetic material. Coils 3 with wire 1 are installed on the housing 5 with the possibility of replacing them after the stock of wire is used up. RF antennas 6 are placed inside the housing 5 coaxially with it (the diagram shows a version of a mini-helicon engine with one RF antenna) and are each connected to its own RF radiation generator (not shown in the diagram). The guides 2 are also mounted on the housing 5 so as to ensure unhindered winding of the wire 1 from the coils 3 and its supply to the engine. The wire feeder 7 in the simplest case can be two electrically driven rollers (not shown in the diagram). Grooves are made on the rollers according to the number of simultaneously fed wires.

The engine works as follows.

Before launching the spacecraft or before a new cycle of operation, the working fluid, which is a wire 1 made of ferromagnetic material, is tightly wound on coils 3, also made of ferromagnetic material. Fully wound coils are magnetized in the direction of the coil axis, after which they become permanent magnets. Then the coils are mounted on the motor housing 5 on bearings 4 so that the axes of rotation of the coils coincide with the axis of the motor. The outer ends of the wires from all coils are fed into the engine through the guides 2 and the wire feeder 7. The coils 3 create a longitudinal magnetic field inside the engine, and at the ends of the housing 5 - an expanding magnetic field. After turning on the power supply, the wire feeder 7 feeds the wire at a given speed simultaneously from all coils 3 through guides 2 inside the first (or the only one in the accelerating path) RF antenna 6. Coils 3 rotate around the motor housing 5 on bearings 4. Antenna 6 is powered by generator of RF radiation (not shown in the diagram). The wire feed speed is set by the control system (not shown in the diagram) of the engine or spacecraft depending on the power of the RF radiation. During the operation of the RF antenna 6, heating to a temperature of the order of (1300-1550) ° C occurs and the ends of the wires 1 melt and the formation of molten metal drops at the ends, which are held by the surface tension of the liquid metal. From the surface of each drop, the material evaporates and the resulting gas is ionized by electron impact. The first RF antenna along the path operates at one of the helicon plasma frequencies (of the order of 10-15 MHz) and is mainly intended for accelerating the electronic component of the plasma. In addition, part of the RF energy is spent on heating, melting and evaporation of the wire material. In the version of the mini-helicon engine, this antenna is the only one. In the full version of the helicon engine, a second RF antenna is installed behind the first one, operating at an ion cyclotron resonance frequency (of the order of 5-10 MHz) and designed to accelerate the ion component of the plasma. Under the influence of RF radiation, charged particles rotating around magnetic field lines increase their speed and radius of rotation. Engine thrust occurs when accelerated charged particles pass through a “magnetic nozzle” (field lines are not shown in the diagram), i.e. through the region of divergent magnetic field lines. In this region, the Lorentz force acting on particles perpendicular to the lines of force acquires an axial component, and particles acquire an axial component of their velocity.

During the operation of the engine, the wire is consumed and the magnetic field induction decreases, however, other, non-magnetic coils with wire can be included in the propulsion system. In this case, it is advisable to first use the wire from non-magnetic coils, and then from magnetic ones, while the induction will be sufficient almost until the working fluid is completely used up. In addition, the coil bodies 3 are also permanent magnets and they are not consumed during operation. After the wire is completely used up, the coils are replaced with new ones. For dense winding on the coil, the wire can have a square section. The length and diameter of the coils are selected from the condition of providing the required configuration of the magnetic field, however, it is desirable that the length of the wire on all coils be the same.

For example, hard magnetic steel (GOST 24897-81) can be used as a ferromagnetic material for wires and coils; an alloy of iron and (1.2-1.5)% carbon, or an alloy of neodymium-iron-boron Nd ₂ Fe ₁₄ B (GOST R 52956-2008). In the latter case, the magnetic field induction on the motor axis can reach 0.5 T. The melting points of all these alloys lie in the range (1300-1550)°C. The motor housing, guides and wire feeder can be made of non-magnetic steel, for example, 12X18H10T (GOST 5632-72), RF antenna - from silver (GOST 6836-2002) or copper (GOST 434-78). A half-turn radiator is used as a radio frequency antenna, and a magnetron is used as a radio frequency radiation generator.

Estimates show that with an electric useful power of the engine of 200 kW in the helicon version (as in the prototype), the plasma outflow speed is 35 km/s, the thrust is 7 N, the steel wire feed speed with a cross section of 1.5 × 1.5 mm is 11 mm/s , steel consumption is 0.2 g / s, power consumption for heating the wire is 0.1%, for melting 0.7%, for evaporation 1%, for ionization 2% and for ion acceleration 96% of the useful power expended. To ensure the required rate of metal evaporation from the surface of molten drops, the total surface area of metal drops at the ends of the wires must be equal to 700 mm ² . If there are two such drops, the radius of each should be 5.3 mm.

The use of iron alloys as the working fluid of electric jet engines has two advantages over argon used in the prototype. The atomic mass of iron (56 a.m.u.) is greater than that of argon (40 a.m.u.), which means that the engine thrust when operating on iron is 18% higher than when operating on argon at the same electric power engine. In addition, iron is a common element in space, including on the Moon, and this allows us to consider the Moon as a raw material and industrial base for astronautics.

Claims (1)

Magnetoplasma electric propulsion engine, containing a housing, at least one ring magnet and a radio frequency antenna connected to the radio frequency radiation generator, a working fluid in the form of a wire and at least one coil for its storage, as well as guide elements and a wire feeder, characterized in that coils with wire wound on them are placed on the outer surface of the housing on bearings and the axis of rotation of the coils is aligned with the axis of the motor, and the wire and coils are made of ferromagnetic materials, jointly magnetized before use in a direction parallel to the axis of the motor, and used as permanent ring magnets, wherein the wire feeder is configured to jointly feed wire from all spools at an adjustable speed depending on the power of the radio frequency radiation.

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