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    • 专利摘要:
    Pulsing electric nozzle to increase thrust in plasma space motors. The invention comprises a plasma motor (1) that ejects a flow of quasi-neutral plasma to the outside of a conical nozzle (2), formed by a network of conductive cables (4) without insulating coating, to which pulses are supplied of potential by means of a power source (3) generating pulses and an ejector device (6) that expels the particles collected by the cables (4). Part of the flow of particles generated by the plasma engine (1) is repelled, by means of coulomb forces, with the pulses produced along the conductor cables (4), creating a thrust in the same direction as that generated by the plasma motor (1), increasing the net thrust of the system formed by the plasma motor (1) and the nozzle (2). (Machine-translation by Google Translate, not legally binding)
    公开号:ES2596721A1
    申请号:ES201630030
    申请日:2016-01-15
    公开日:2017-01-11
    发明作者:Antonio SÁNCHEZ TORRES
    申请人:Antonio SÁNCHEZ TORRES；
    IPC主号:
    专利说明:

    DESCRIPTION

    Pulsed electric nozzle to increase thrust in plasma space motors

    Technical Field of the Invention
    The present invention is framed within the field of aerospace engineering, within primary or secondary space propulsion systems for space vehicles and satellites. In particular, the invention pertains to systems that use plasma to produce a thrust thrust per reaction.

    State of the art
    Plasma space motors, also called electric thrusters, are capable of producing a low thrust and a high specific impulse much greater than that provided by conventional chemical propulsion systems. These plasma engines reduce fuel consumption. The electric propulsion can be defined as the acceleration of gases by means of the propulsion generated by electric heating and / or by electrical and magnetic procedures. The different types of space electric propellants can be divided into three main types of systems: electro-thermal propulsion, in which the fuel in the gas state is electrically heated and subsequently is expanded by means of a nozzle with a non-electric characteristic. ; electrostatic propulsion, where the fuel is accelerated by the direct application of electrical forces to ionize the particles; Electromagnetic propulsion, where an ionized fuel is accelerated through the interactions of external and internal magnetic fields with electrical currents produced in the plasma.

    There are different types of thrusters, depending on their propulsive characteristics. One of the biggest problems that all existing space plasma engines have in common is the high electrical power they require to achieve high thrusts, which requires unattainable power systems in space. Normally the electrical power is achieved by means of solar panels or radioisotope power generation systems, so that it is not possible to generate an excessively high electrical power (<100 kW), unless nuclear fission reactors are used, rather than Space Agencies want to avoid, due to its cost and its high weight and size, in addition to the implications that this would entail in relation to public opinion.

    At low power, electric thrusters generate very small thrusts. A Hall-type engine such as SMART-1 generates 68 mN at 1.2 kW and a 0.65 kW helicon engine would generate 2.8 mN. Ionic engines such as NSTAR and NEXT produce thrusts of 92 and 236 mN for powers of 2.3 kW and 6.9 kW, respectively.

    There are also other groups of experimental plasma motors such as the inductive pulse (PIT), which would reach values between 1 and 5 Newtons of thrust for a power between 40 and 200 kW. The PIT engine consists of a set of cables with insulated coating arranged in a spiral, a nozzle that injects the fuel and a pulsating power supply. The nozzle injects the fuel covering the surface of cables and the power supply generates high current pulses in the cables, generating a magnetic field that varies over time, inducing an intense electric field in azimuthal direction in the region near the cables. The intense electric field allows the fuel to be transformed into plasma with azimuthal currents that depend on the increase in current supplied to the cables. Finally, the interaction of the current developed in the plasma and the magnetic field produced by the cables generates a Lorentz force that accelerates the plasma axially from the cables, producing the desired thrust.

    The VASIMIR motor is a combination of a helicon motor, together with a radiofrequency heating system and finally the plasma is ejected by a magnetic nozzle, in which the magnetic field of the nozzle guides the flow of the plasma. The VASIMIR thruster achieves 1.5 and 5 N propulsive forces by consuming a power of 100 and 200 kW, respectively. The Dual-Stage 4-Grid (DS4G) ionic engine that is currently being developed by the European Space Agency can produce 2.5 N with a power of 250 kW. The powerful magnetoplasmadinamic (MPD) motors can generate a thrust of 25 N considering a power of 500 kW.

    Also, it has been considered the grouping of similar plasma engines ("cluster") so that all of them produce a higher thrust in a certain direction, but it raises problems of sizing of the complete system and the problem of the high power that would require the set of thrusters.

    In summary, to overcome these important limitations, a light system is needed that can generate the greatest thrust with the minimum electrical power that the entire propulsive system allows.

    Brief Description of the Invention
    The invention relates to a nozzle formed by a set of conductive cables that will be coupled to the output of a plasma motor. Lead wires are supplied with positive or negative potential pulses by means of a pulse generating power supply, or simply, by a pulse generator. The quasi-neutral plasma flow (equal charge density of electrons and ions) made up of ions and electrons is ejected at the output of the plasma motor with a divergence angle . Part of the electrons and ions of the flow will be, respectively, collected and repelled by the nozzle conductive cables if pulses of positive potential occur. On the contrary, part of the ions and electrons of the flow will be, respectively, collected and repelled by the conductive cables of the nozzle if negative potential pulses occur. To maintain the correct sign (positive / negative) of the pulses in the conductive cables, the particles (electrons / ions) collected by the cables must be ejected by means of an ejector device. In this way, if positive potential pulses occur in the cables, the ejector device will eject electrons, while if negative potential pulses occur in the cables, the ejector device must expel ions.

    Unlike the PIT plasma engine, the present invention considers conductive cables without insulating sheathing; essential to produce the repulsive force of Coulomb from the repelled particles instead of the Lorentz force, which is produced in the plasma itself, and which uses the PIT plasma engine.

    In the present invention, the arrangement of the cables will be symmetric surrounding the conical structure of the nozzle of diameter Rn. To obtain an effective thrust, the nozzle will have a conical opening with an angle , which will be less than the divergence angle  of the quasi-neutral plasma flow. Due to the symmetry of the nozzle, the particles diverted by the repulsive action of the potential pulses will produce a thrust on the system in the opposite direction to the direction of the quasi-neutral plasma flow expelled by the plasma engine. Additionally, the repelled particles will undergo an acceleration due to the potential pulses and will leave the outside of the nozzle at a higher speed than when they entered the region of influence of the potential of the cable.
    In the present invention two cases of potential pulses are proposed along the conductive cables: positive and negative. Conductive cables will be applied pulses of peak-to-peak potential, the lower pulse potential, pb, being approximately equal (although slightly higher) than that derived from the plasma flow produced by the plasma motor; pb≈ Ep / e = 0.5 mpvp2 / e, where Ep is the energy of the particle flow, e is the charge of the electron, mp and vp are, respectively, the mass and velocity of the particle considered to be repelled by the conductive cables. Ions such as Xenon, Argon, Neon, Krypton or other type of ion in the plasma flow produced by the plasma engine can be considered. The ions will be repelled when positive potential pulses appear in the cable assembly, well the electrons will be the repelled particles when negative potential pulses are generated. The pulses will be generated by means of a pulse generating power supply.

    In the potential pulse supplied in the cables, the lower level of the potential, pb, is positively or negatively polarized with respect to the plasma flow. A distinction must be made between positive or negative polarization of the cables with respect to the plasma produced by the plasma engine to know what kind of particle will be attracted and repelled by the conductor cables. For positive polarization of the conductor cables, the ions and electrons are, respectively, repelled and collected by the cables. In the case of negative polarization (see Sanchez-Torres, A., Drag and propulsive forces in electric sails with negative polarity, Advances in Space Research, Vol. 57, No. 4, pp. 1065-1071, 2016), electrons they are repelled and there is a population of repelled ions and another population collected by the conductor cables.

    In this patent, the incidence of electron repulsion by negative potential pulses will be considered, in particular, although a part of the ion population, which is considered small, can be repelled by the high pulse level. , | pa |. In the case of positive potential pulses, the mass and velocity of the particle to be considered in | pb | ≈Ep / e will be the mass of the ion and the flow of ions. However, for negative potential pulses the mass of the electron, me, and the thermal velocity of the electron will be considered, so that it has | pb | ≈kBTe / (2e). /, pteBeevvkTm

    It is essential to emphasize that the network of conductive cables has nothing to do with the grids system ("grids") that are usually used in plasma motors, such as the type of ionic propellant. The grilles of these motors that are used to accelerate the plasma ions are surfaces with holes of small diameters of the order of 0.55 mm. Regarding the invention presented here, the nozzle is formed by a network of conductive cables (not by the
    type of surface grilles with holes). In the present invention, each conductor cable is separated by its immediate neighboring cable at a distance that must be studied according to the conditions of the ambient plasma (temperature, density) and the characteristics of the cable (length, diameter) and the potential at which the cable is submitted. In a first approximation, that distance equivalent to the radius, rsb, of the electrical sheath created by the low potential pulse pb, determined by the following equation can be considered (see reference: Sanmartin JR, et al., Bare-Tether Sheath and Current: Comparison of Asymptotic Theory and Kinetic Simulations in Stationary Plasma, IEEE Trans. Plasma Sci., vol. 36, no. 5, pp. 2851-2858, 2008),
                                                        (A) 4/54 / 31.5312.56ln, pbsbsbDsbDeerrrRkT
    where D is the length of Debye, R is the radius of the cable, kB is the Boltzmann constant, np is the density of particles, e is the charge of the electron and Te is the temperature of electrons in the plasma, which is considered same as that of ions in this case. / 4BepkTn

    The object of the present patent refers to a pulsating electric nozzle to increase the thrust in plasma space motors and reduce the electrical power of the total system. The patent includes several embodiments. The common elements of the invention according to the different embodiments would be characterized by:
    - a plasma motor that ejects a quasi-neutral flow of plasma out of a conical nozzle, formed by a conductive cable structure without insulating coating, to which potential pulses will be subjected;
    - a pulse generating power supply;
    - an ejector device that expels the particles collected by the nozzle formed by the cable structure to which potential pulses are subjected;
    - an annular structure at the end of the nozzle to keep the conductive cables that make up the nozzle tense.
    As regards the particular elements according to the main embodiment:
    - a network of conductive cables subject to negative potential pulses.
    With regard to the particular elements according to another embodiment:
    - a network of conductive cables subject to positive potential pulses.

    It is proposed to transmit a thrust by means of a moment exchange of the flow of the particles that, ejected by the plasma engine, are repelled by the virtual surface produced by pulses of potential generated in the conductive cables that make up the nozzle. The procedure considered in this invention is similar to that proposed in the patents of the same author of the present invention (patent P 201431740 and patent application P201531029). In the previous patents the repulsion of ions was considered. However, in the present invention the repulsion of electrons produced by negative potential pulses will also be considered, which is the main case studied in the present patent. A potential pulse that is supplied to the conductor cables is used, where the lower potential is | pb | ≈Ep / e = kBTe / (2e) and the upper potential is | pa | ≈ | pb | + |   |, where |  | it is the difference of potential peak to peak that can be of the order of 1 kV or greater. The radius of the sheath, rsa, generated by the superior pulse potential | pa | It can be calculated by substituting rsb for rsa, and pb for pa in equation (A). The electrons that arrive from the plasma motor to the nozzle are stopped by the lower pulse potential, | pb |, until reaching a position of maximum approach, r0, where they begin to be repelled. Once the electron reaches that position, r0, the upper pulse potential, | pa |, produces a repulsion on the electron; accelerating in the opposite direction to the initial one until it travels the entire distance of the new sheath, from r0 to rsa, generated by that high pulse potential | pa |.

    Another difference with respect to the patent application P201531029 is: the particles repelled by the conductive cables are sent out of the nozzle, away from the plasma engine.
    The repulsive force of Coulomb that repels electrons out of the nozzle also transfers a force on the pulsing electrical structure of the nozzle, and therefore produces a propulsive force in the opposite direction with which the repelled electrons move by the pulsating electric nozzle, which can be estimated as
                                                                            (B) cos2cos, NppfNFnmvLR
    where L is the length of each nozzle cable, RN is the final radius of the nozzle; np is the density of repelled particles; mp is the mass of the repelled particle. In the case of negative potential pulses, the repelled particle is the electron, while in the case of positive pulses the repelled particle is the ion. The repelled particle ejected by the potential acquires a much higher velocity, vf, when it leaves the sheath produced by the higher pulse potential, pa, than when it enters the sheath produced by the lower pulse potential, pb.

    For the present invention, the material of the conductive cables must be a good electrical conductor, withstand high temperatures and have a low density. It can be considered aluminum, molybdenum, or also include some type of carbon fiber, steel alloys or kevlar.
    The maximum electrical power consumed by the conductive cables that make up the nozzle is
                                                                                  (C) elpaavPI
    where the maximum voltage produced in the pulse is | pu | and the current Iav that the particle ejector device must expel is
                                                                                        (D) 2, paavcppeINeRLnm
    where Nc is the number of wires. Very thin cables must be used; of the order of a few microns in diameter. Assuming a cable network to which negative pulses are supplied with Nc = 2600, R = 20 m, L = 0.3m, RN = 0.19m, | pu | = 590V, and considering xenon as the ion used (mp = 2.2 ∙ 10-25 kg), an average particle density of np = 2.4 ∙ 1010 cm-3 along the surface surrounding the nozzle, and a temperature of Te = 2 eV with an angle of divergence  = 40º and  = 39º, the current necessary to eject the xenon ions, which is obtained according to equation (D), is Iav = 1.76 A, and the power, according to the Equation (C), is Pel = 1 kW. With these parameters the electrons accelerate at speeds that reach vf = 14420 km / s, so that a force, FN, is obtained, given equation (B), of 0.80 N. Assuming that the power used by the plasma motor that generates conditions such as those described are about 200 W and a plasma motor thrust, Fp = 1 mN, we would have a total system power of 1.2 kW and a net force FN + Fp = 0.80 N of total force, which is much greater than that produced by any type of space plasma engine with that power. With that same power, the SMART-1 Hall PPS-1350 engine would generate 0.068 N; a propulsive force about 12 times less. If we increase the potential to | pu | = 910 V the electrons would accelerate at speeds vf = 17900 km / s, so that a force of 1.25 N would be obtained, for a current Iav = 2.19 A and a power of 2 kW. The present invention allows generating forces of 1 N at low electrical power; There is currently no plasma engine that can achieve that force at such low electrical power. Normally, achieving that force in current plasma engines requires powers greater than 100 kW, that is, more than one hundred times the power that the present invention would require in the form of a nozzle. This is a breakthrough in terms of generating moderately high thrust at low electrical power. In addition, if we greatly increase the length of the cables and the final radius of the nozzle (L = 3.17 m, RN = 2 m) and reduce
    considerably the potential (| pu | = 190V) significant thrusts (FN = 3.11 N) at low power (Pel = 0.76 kW) would be obtained. This allows you to choose between a wide range of lengths and potentials depending on the type of space mission required, even allowing you to vary the length and potential according to specific mission requirements.

    At high powers and lengths of the nozzle rather large, quite high forces could be achieved. Assuming a negative polarized network with Nc = 5000, R = 20 m, L = 1 m, RN = 0.63m, | pu | = 7.57 kV, and considering an average particle density np = 7.8 ∙ 109 cm-3 along the surface surrounding the nozzle with that length of cables, and a temperature of Te = 2 eV, with an angle of divergence  = 40º and  = 39º, the current obtained is Iav = 13.2 A, and the power is Pel = 100 kW. With these parameters the electrons accelerate at speeds vf = 51620 km / s, so that a force of 37.7 N. is obtained. If we increase the potential to | pu | = 20 kV the electrons would accelerate at speeds vf = 83880 km / s, so that a force of 100 N would be obtained, for a current Iav = 21.5 A and a power of 430 kW, much higher than the force achieved by any motor of Plasma at that power. In addition, if we further increase the length of the cables and the final radius of the nozzle (L = 7.94 m, RN = 5 m), with a high potential (| pu | = 16.44 kV), quite high thrusts would be obtained (FN = 692 N) at a very high power (Pel = 1 MW). For the aforementioned, the present invention is a system scalable in length and potential that would generate a much greater thrust than any plasma motor alone, both at low and high power.

    For the alternative mode of positive potential pulses supplied to the nozzle conductive cables, the electron current collected by the cables will be quite high since according to equation (D),. Since the mass of the electron is me = 9,109 ∙ 10-31 kg (4 or 5 orders of magnitude lower than that of ions) the required power, given equation (C), will be several orders of magnitude greater than that of the main mode of negative pulses. In this way, the option of negative potential pulses supplied in the cables will be more effective in terms of power reduction than that of positive pulses. 1 / aveIm

    It is important to note that the number of necessary conductive cables can be much smaller, since interference phenomena can occur between the cables resulting in a much smaller effective current collection. In this way, due to interference effects it is expected that the current collection can be reduced by 50%, and therefore the power
    required, also, 50% lower to obtain the same propulsive force; further increasing the performance of the pulsating electric nozzle.

    The use of the nozzle does not significantly affect the mass of the entire system despite the large number of cables required. The conductive cables are very thin (R = 20 m) and if we consider the use of aluminum (density,  = 2700 kg / m-3), for 5000 cables of 1 m in length it means a mass of 0.017 kg for the entire nozzle. If the material of the cables were molybdenum (density,  = 10280 kg / m-3) the total mass of the nozzle would be only 0.065 kg.

    The present invention will increase the initial propulsive force of the plasma engine. The reduction in power of the entire propulsive system is achieved by minimizing the power required of the plasma motor (around 200 W) and increasing the Pel power that will be required by the pulse generating power supply and the particle ejector device. In this way the ratio between the force and the power (FN / Pel) of the complete system is much greater than in the case of a plasma motor alone; that is, the complete propellant system (plasma motor and pulsating electric nozzle) will need a lower electrical power to generate the same force as a plasma motor alone. Therefore, the present invention of the pulsating electric nozzle that is coupled to the output of a plasma motor allows greater thrust with lower electrical power in relation to the prior art.

    Once the technological limits of the thrust system have been defined, the detailed description of the invention can be passed according to the embodiments.


    Description of the figures
    To complement the description and in order to help a better understanding of the features of the invention, the present specification of figures 1 to 6 is attached, as an integral part thereof.

    The invention will be described in the following in more detail with reference to various embodiments thereof represented in said figures.

    Figure 1 represents the structure of the nozzle (2) that is attached to the plasma motor (1) with a network of very fine conductor cables and without insulating coating (4). The design of the conductor cable network (4) has a symmetrical arrangement and terminates each cable (4) in an annular cable (7). Several auxiliary conductive cables (8) of greater cross-section come out from the annular cable (7) that contact a common point (9). At that point (9) a particle ejector device (6) will be placed that will eject ions (electrons) if negative potential (positive) pulses are maintained in the lead wires (4). The nozzle has an annular structure (5) that confers tension on the conductor cables (4).

    Figure 2 represents another type of design of the structure of the nozzle (2) that is attached to the plasma motor (1) with a network of very fine conductor cables and without insulating coating (4). The design of the conductor cable network (1) has a symmetrical arrangement and terminates each cable (4) at a common point (9). From that point (9) a particle ejector device (6) will be placed that will eject ions (electrons) if in the conductive cables (4) negative (positive) potential pulses are maintained. The nozzle has an annular structure (5) that confers tension on the conductor cables (4).

    Figure 3 represents the mode of operation of the nozzle (2) coupled to the plasma motor (1), which ejects a quasi-neutral plasma flow (practically equal density of ions and electrons) with a divergence angle  with respect to the horizontal The arrangement of the conical nozzle (2) has an angle respecto with respect to the horizontal. The angle of divergence  must be greater than or approximately the same as angle . The distance between the plasma motor (1) and the end of the nozzle (2) is d, and the final radius of the nozzle (2) is RN. The length of each cable is L. The plasma motor (1) generates a propulsive force Fp in the opposite direction to the flow of quasi-neutral ejected plasma. The force FN produced by the cables (4) that form the nozzle (2) has the same direction as Fp.

    Figure 4 represents the ejector device (6) of particles inwards. The ejector device (6) is coupled to the pulse generating power supply (3), which is connected to the common point (9) where it joins the conductor cables (4) or the auxiliary cables (8) . The ejector device (6) must be located in such a way that it does not harm the plasma engine (1) and can improve, if possible, the generation of particles in the plasma that occurs in the plasma engine (1).

    Figure 5 represents the ejector device (6) of particles outwards. The ejector device (6) is coupled to the pulse generating power supply (3), which is connected to the common point (9) where it joins the conductor cables (4) or the auxiliary cables (8) .

    Figure 6 represents a diagram of the invention according to the main embodiment, in which the mission control module (11) allows more or less electrical power to be supplied to the power system (10) to keep the plasma engine running. (1), to the pulsating electrical structure of the conductor cable network (4) and to the ion ejector device (6) by means of a pulse-variable power supply (3). An optional device such as the accelerometer (12) shows the mission control module (11) what the real thrust the vehicle needs to carry out the orbital maneuver.

    Figure 7 represents a pulse of square wave potential as a function of time t that will be considered as the main embodiment. Both the lower level are shown | pb | as superior | pa | of the pulse, the amplitude of the pulse |  |, the period of the pulse T, and the time  that the pulse is maintained at its upper level | pa |. The range of the duty cycle ( / T) of the invention can be between 0 and 100%. The two extreme values (0 and 100%) in the pulse duty cycle give rise to purely electrostatic situations (no pulses exist); that is, in the case of a 0% duty cycle, the potential spectrum is maintained for the entire time in | pb | ≈Ep / e, while a 100% duty cycle the potential is maintained at all times at high level | pa |. It should be noted that another type of pulse can be considered: triangular, ramp, sine, or other arbitrary wave function. In addition, the optimum values of all parameters (temperature, density, plasma flow rate, length and radius of the conductor cables, in addition to the values of the lower and upper level of the potential pulse, and cycle) should be analyzed experimentally. working) that maximizes the propulsive force with the lowest electrical power consumed. The time it would take for the particles from the plasma motor to travel the distance rsa -r0 would be of the order of T- so that the time in which the pulse is inactive, at its low level, allows the particles to approach to position r0.

    Detailed description of the invention
    The known input parameters are the distance d from the plasma motor (1) to the end of the nozzle (2), the length L and radius R of the conductor cables (4), the divergence angle of the flow , an angle respecto with respect to the horizontal, and the final radius, RN, of the
    nozzle (2). With regard to the output parameters, we have the force Fp that is provided by the plasma engine and FN the force produced by the moment transfer in the repulsion of the particles by means of the network of conductive cables (4) , which make up the nozzle (2), subjected to potential pulses.

    The operation of the invention according to various embodiments thereof is explained below. For this, all common devices involved in the design of the invention are listed, which, according to the different embodiments, are:

    Plasma engine (1): is any type of electric propellant that produces a flow of ions out of the nozzle (2). It can be an ionic engine, Hall, MPD, helicon, VASIMIR, PIT, or any of its variants. The greater the angle of divergence provided by the engine, the propulsive performance can be improved in addition to reducing the size of the nozzle (2). The plasma motor alone generates a force Fp in the opposite direction to the ejection of the quasi-neutral plasma.

    Nozzle (2): formed by a network of conductive cables (4) devoid of insulating sheathing, surrounding the plasma motor (1). The network of conductive cables (4) are arranged following a conical symmetry with an angle  from the central position of the plasma flow produced by the plasma motor (1). The network of conductive cables (4) generates a pulsating electrical surface that produces a moment exchange with the flow of the particles directed by the plasma motor (1), generating an additional FN force, which due to symmetry conditions, carries the same direction than the force Fp produced by the plasma motor (1). Given the pulsating characteristic of the cable network (4) and to avoid the modification of the flow of the particles in directions perpendicular to the initial flow, an arrangement of the fully symmetrical conductor cables (4) is used. The network of conductive cables (4) will be powered by a pulse generating power supply (3).

    Particle ejector device (6): to maintain the appropriate sign of the pulses in the conductor cables (4). With the implementation of the invention the ions (electrons) found in the plasma generated by the electric motor (1) are collected by the network of conductive cables (4) subjected to pulses of negative (positive) potential. These ions (electrons) collected by the conductive cables (4) must be ejected outwards or inwards as described in Figures 3 and 4 to prevent the conductive cables (4) from being electrically charged with the sign of the particles that collect. This way, if the wires
    conductors (4) are subjected to positive potential pulses by means of the pulse generator (3), the electrons collected by the conductive cables will be ejected by the ejector device (6). On the contrary, if the conductive cables (4) are subjected to negative potential pulses by means of the pulse generator (3), the ions collected by the conductive cables will be ejected by the ejector device (6). With regard to the expulsion of particles, the ejection of particles into the interior is considered as the main case, providing the plasma engine (1) with greater ion density (electrons). Any type of method to maintain potential pulses can be considered; in the case of positive potential pulses, a plasma contactor, cathode by thermionic emission and emission networks by field effect can be chosen. In the case of negative potential pulses, ion ejectors ("ion gun"), also referred to as ion sources ("ion source") will be used. The structural elements of both electron and ion ejectors are similar, except that ion ejectors manage to generate ions directly from the ionization of the surface of an alkali metal or indirectly generating electrons that will subsequently ionize a gas - which can be xenon, argon , krypton, etc. In the latter case - the generation of electrons for the subsequent ionization of a gas - electrons can be produced by means of a plasma contactor, cathode by thermionic emission or by emission networks by field effect.

    Power system (10): Provides the power needed to power the plasma motor (1), the network of conductive cables (4), particle ejector device (6), the pulse generating power supply (3), and the measuring instruments on board the vehicle. It can be any: solar panels, electrodynamic moorings, nuclear system, high voltage power supplies, etc. A control regulator must also be included to supply the electrical power required by the plasma motor (1), and the network of conductive cables (4) together with the particle ejector device (6).
    Optional devices:
    Accelerometer (12): to measure the acceleration produced by the nozzle of the present invention, when the potential supplied to the conductor cables (4) or the electrical power of the plasma motor (1) is modified.

    Solenoids, which can direct particles leaving the plasma engine (1), at angles  different from those initially produced by the plasma flow generated by the plasma engine (1). This would allow to modify the angle with which the particles come into contact with the potential pulses generated along the conductive cables (4), and thus modify the propulsive force given by equation (B).

    Optionally, it could be included in the initial part of each conductor cable (4), which forms the nozzle (2), a segment of cable with insulating coating to avoid any damage to the plasma motor (1) by particles repelled near it .

    Main embodiment:
    The invention, which is implemented in a space vehicle, has a power generation system (10), a plasma engine (1) that produces quasi-neutral plasma with a flow of particles directed towards a nozzle (2) formed by a network of cables (4) to which negative potential pulses are supplied, which repel plasma electrons out of the nozzle (2) to generate a momentum transfer that propels the entire system. The plasma motor (1) produces a thrust Fp in the direction described by Figure 3. The moment transfer of the electrons over the conical structure of the nozzle (2) to which potential pulses is supplied provides, by symmetry, a thrust FN in the same direction as Fp .. As the thrust generated by the structure of conductive cables (4) that make up the nozzle (2), is much greater than that achieved by a plasma motor (1), a FN direction acceleration much greater than that provided by the plasma engine itself (1). The regulator in the power system (10) controls the ejection speed of the quasi-neutral plasma flow and the potential with which the pulses are maintained in the network of conductor cables (4). Negative polarized conductive cables (4) collect ions along their length, which must be ejected by a particle ejection device (7) to maintain the negative pulses of said conductive cables (4). The pulse generating power supply (3) is connected to the ion ejection device (6) and to the conductive cables (4) that make up the nozzle (2). Figures 3 and 4 show two possible uses of the ion ejection device (6), with ejection into the plasma motor (1) or the ejection is carried out towards the outside of the system. For this main embodiment, the ion expulsion is chosen by means of the ion ejection device (6) inwards, providing the plasma engine (1) with greater ion density. For this main embodiment, an ion ejection device (6) will be used by means of ionizing the xenon gas considering a cathode by thermionic emission.

    For an embodiment of the secondary invention, the nozzle (2) formed by conductive cables (4) subjected to positive voltage pulses, will produce a force FN similar to that of the main embodiment of the invention, but the power required it will be higher, since Pel  1 / me, and electrons have a much smaller mass than that of ions.

    One or more plasma motors (1) can be used as redundant systems for any of the embodiments of the invention.
    权利要求:
    Claims (17)
    [1]

    1. Pulsed electric nozzle to increase the thrust in plasma space motors by means of the repulsion of a flow of particles directed from a plasma motor that ejects a quasi-neutral plasma into a conical nozzle formed by a network of pulsed cables of potential, characterized in that it comprises:
    - a plasma motor (1) with ejection of a flow of ions and electrons with an angle of divergence  directed towards a network of cables (4) arranged symmetrically and conically in the form of a nozzle (2) with an angle  somewhat smaller than the angle of divergence ;
    - a network of conductive cables without insulating sheathing (4) subjected to potential pulses that repel particles out of the nozzle (2);
    - an ejector device (6) that ejects particles to maintain the sign of the potential pulses in the network of conductive cables (4);
    - a mission control module (11) configured to activate the electric power generator (10) and regulate the electric power that supplies potential pulses to the conductor cables (4) through a pulse generating power supply (3 ), to the plasma engine (1) and the ejector device (6) of particles;
    - an annular structure (5) located at the end of the nozzle (2) that maintains the tension of the network of conductive cables (4)

    [2]
    2. System according to claim 1, characterized in that the pulse generating power supply (3) supplies negative potential pulses to the conductive cables (4) and the ejector device (6) expels ions.

    [ 3]
     3. System according to claim 1, characterized in that the pulse generating power supply (3) supplies positive potential pulses to the conductor cables (4) and the ejector device (6) ejects electrons.

    [4]
    4. System according to claim 1, 2, or 3, characterized in that the network of conductive cables (4) that make up the nozzle (2) are connected to an annular structure (7) that is coupled to the output of the plasma motor ( one). From this annular structure (7) there are several auxiliary cables (8) that meet at a point (9), where it is connected to the pulse generating power supply (3). The pulse generating power supply (3) is also connected to the particle ejection device (6).

    [5]
    5. System according to claim 1, 2, or 3, characterized in that the network of conductive cables (4) that make up the nozzle (2) meet at a point (9), where it is connected to the pulse generating power supply ( 3). The pulse generating power supply (3) is also connected to the particle ejection device (6).

    [6]
    System according to any one of the preceding claims, characterized in that the particle ejector device (6) ejects the particles into the plasma engine (1).

    [7]
    System according to any one of the preceding claims, characterized in that the particle ejector device (6) ejects the particles towards the outside of the system.

    [8]
    System according to any one of the preceding claims, characterized in that the potential pulse has a rectangular, triangular, ramp, sine or other arbitrary waveform. The system works with a duty cycle within the range 0-100%.

    [9]
    9. System according to any one of the preceding claims, characterized in that the plasma motor (1) is an ionic motor, Hall, MPD, helicon, PIT, VASIMIR, or any of its varieties.

    [10]
    10. System according to any one of the preceding claims, characterized in that the system formed by the plasma motor (1) is redundant.

    [11]
    System according to any one of the preceding claims, characterized in that the system formed by the mission control module (11) uses the accelerometer (12) as a measuring element to supply electric power from the power system (10).

    [12]
    12. System according to any one of the preceding claims, characterized in that some type of solenoid or a group of solenoids is incorporated into the system that modifies the initial direction of the particles ejected by the plasma motor (1), changing the angle with which these particles interact with the potential of the conductive cables (4), and thereby altering the propulsive force.

    [13]
    13. System according to any one of the preceding claims, characterized in that a small segment of each conductor cable (4) has an insulating coating to avoid damage to the plasma motor (1) by particles repelled near it.

    [14]
    14. System according to any one of the preceding claims, characterized in that the plasma motor (1) ejects a flow of neon, argon, krypton, xenon, mercury ions.

    [15]
    15. System according to any one of the preceding claims, characterized in that the particle ejector device (6) ejects said particles by means of a thermionic emission system.

    [16]
    16. System according to any one of the preceding claims, characterized in that the particle ejector device (6) ejects said particles by means of a plasma contactor.

    [17]
    17. System according to any one of the preceding claims, characterized in that the particle ejector device (6) ejects said particles by means of a system of emission networks by field effect.

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    同族专利:
    公开号 | 公开日
    ES2596721B1|2017-11-06|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5924278A|1997-04-03|1999-07-20|The Board Of Trustees Of The University Of Illinois|Pulsed plasma thruster having an electrically insulating nozzle and utilizing propellant bars|
    US7530219B1|2002-06-14|2009-05-12|Cu Aerospace, Llc|Advanced pulsed plasma thruster with high electromagnetic thrust|
    WO2015031447A1|2013-08-27|2015-03-05|The Regents Of The University Of Michigan|Converging/diverging magnetic nozzle|
    US20150307214A1|2013-11-29|2015-10-29|Thales|Thrust nozzle system and method for the orbit and attitude control of a geostationary satellite|
    ES2498716A1|2014-08-19|2014-09-25|Antonio SÁNCHEZ TORRES|Space propulsion system by electrostatic modification |
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