CN113309679A - Pulse plasma thrust device - Google Patents

Abstract

The application relates to a pulse plasma thrust device, the device includes: a propulsion fixing device; the anode plate and the cathode plate are fixed on the propelling and fixing device; the spark plug is used for discharging and ablating the working medium; a capacitor electrically connected to the anode plate (72) and the cathode plate; the ceramic nozzles are arranged in at least two step-shaped arrangement and are arranged between the cathode plate and the anode plate; the ceramic nozzle is used for preventing electric leakage and creepage phenomena when the spark plug discharges and preventing plasma current scattering; the propellant track is communicated with the propellant channel and is used for moving the working medium; the constant force spring is fixed on the propellant track through a spring fixing device and is used for continuously propelling the working medium into the propellant channel through the propellant track; the device can reduce the resistance of a main discharge circuit, and meanwhile, the shape of an accelerating flow channel is improved by arranging the step type nozzle liquid, so that low-speed neutral gas generated by delayed gasification of the propellant can obtain higher speed, and the performance of the pulse plasma thruster is improved.

Description

Pulse plasma thrust device

Technical Field

The invention belongs to the aerospace electric propulsion technology, and particularly relates to a pulse plasma thrust device.

Background

With the development of emerging space technologies such as small satellites, planetary detectors, deep space exploration and the like, the aerospace electric propulsion system is required to be lighter in weight, smaller in size and less in propellant consumption. The traditional chemical propulsion method is increasingly difficult to meet the requirements of emerging space tasks due to low specific impulse and complex structure. The Pulse Plasma Thruster (PPT) is a feasible scheme for a micro-satellite propulsion system, has the advantages of higher specific impulse, light weight, compact structure, small volume, convenient and flexible control and the like, and can be used for space tasks of attitude control, orbit transfer and lifting, orbit correction, resistance compensation, position keeping, off-orbit processing and the like of the micro-satellite.

In recent years, with the continuous improvement of the scientific and technological level of China, people pay more and more attention to the exploration of the aerospace field. Although thrusters are a major power source for aerospace equipment, most thrusters currently use fuel for propulsion, electric propulsion gradually attracts more and more people to research. The electric propulsion has the characteristic that the fuel propulsion does not have, so the research of the electric propulsion technology is particularly important. Meanwhile, the pulse plasma thruster is a valuable novel space electromagnetic thruster, belongs to one of electric propulsion technologies, and is one of the most potential electric propulsion research directions at present. The pulsed plasma thruster can generate smaller thrust but consumes very little whole propellant, so the characteristics support the main application of the thruster in controlling the attitude keeping and the position control of a small satellite, and the pulsed plasma thruster is widely applied in the aspects. The main research related to the pulse plasma thruster aims at optimizing and perfecting the propulsion performance, prolonging the service life, reducing the overall volume and mass and the like.

Therefore, in order to better exert the pushing efficiency and the energy utilization rate of the pulse plasma thruster, the volume and the mass of the pulse plasma thruster are reduced as much as possible on the premise of ensuring the rigidity and the strength. Therefore, it is particularly important to design the mechanical structure of the whole device.

Disclosure of Invention

In view of the above, there is a need to provide a pulsed plasma thruster, which can reduce the resistance of the main discharge circuit, and improve the acceleration flow channel shape by providing a stepped nozzle liquid, so that the low-speed neutral gas generated by delayed vaporization of the propellant can obtain higher speed, thereby improving the performance of the pulsed plasma thruster.

The present invention provides in a first aspect a pulsed plasma thrust device, the device comprising:

a propulsion fixing device;

the anode plate and the cathode plate are fixed on the propelling and fixing device and are arranged oppositely and in parallel;

the spark plug is fixed on the cathode plate and used for discharging and ablating working media;

a capacitor electrically connected to the anode plate and the cathode plate;

the ceramic nozzles are arranged in at least two step-shaped arrangement and are arranged between the cathode plate and the anode plate, the cathode plate and the anode plate are arranged in opposite and parallel, and a propellant channel is enclosed by the ceramic nozzles, the cathode plate and the anode plate; the ceramic nozzle is used for preventing electric leakage and creepage phenomena when the spark plug discharges and preventing plasma current scattering;

the propellant track is communicated with the propellant channel and is used for moving the working medium;

the constant force spring is fixed on the propellant track through a spring fixing device and used for continuously propelling the working medium into the propellant channel through the propellant track.

Optionally, the ceramic nozzle includes at least two insulating plates stacked in sequence, and adjacent insulating plates are arranged in a step shape.

Optionally, a threaded hole is formed in the cathode plate, the axial direction of the threaded hole is perpendicular to the anode plate, and the spark plug is in threaded fixed connection with the cathode plate through the threaded hole.

Optionally, the apparatus further comprises:

a box body;

the plasma jet orifice is arranged on the box body and communicated with the propellant channel, and the plasma flows through the propellant channel and then is ejected out through the plasma jet orifice;

the contraction port of the bell mouth is fixed on the outer surface of the box body, and the contraction port surrounds the periphery of the plasma flow jet port;

and the mounting framework is fixed on the inner wall of the box body and used for fixing the propelling and fixing device.

Optionally, the mounting framework includes:

the front metal plate is fixed on the inner wall of the box body, and the upper part of the front metal plate is provided with an installation station for installing the propelling and fixing device;

the rear metal plate is fixed on the inner wall of the box body, a fixing groove is formed in the upper portion of the rear metal plate, the fixing groove is used for embedding the end portion, far away from the plasma jet orifice, of the propellant track, the rear metal plate and the front metal plate are arranged in a flush mode, and an installation station used for clamping and fixing the capacitor is reserved between the rear metal plate and the front metal plate;

and the first insulating plate is fixed on the side wall, facing the horn mouth, of the front metal plate, and the outer surface of the first insulating plate is wrapped with a conductor material for electrically connecting the capacitor and the spark plug to form a circuit.

Optionally, an insulating material for preventing current leakage is further wrapped on the outer surface of the first insulating plate, wherein the conductor material and the insulating material are at the same distance from the surface of the first insulating plate.

Optionally, the spring fixing device includes:

the constant force spring fixer is fixed at the end part, far away from the capacitor, of the front metal plate and is used for fixing one end of the constant force spring;

and the constant force spring thruster is fixed on the propellant track and used for coiling the other end of the constant force spring.

Optionally, the front metal plate and the rear metal plate are both provided with lightening holes and/or lightening grooves.

Optionally, the advancing fixture comprises:

an insulating block;

the through hole is formed in the insulating block, and the axial direction of the through hole is parallel to the length direction of the propellant track; and the cathode plate, the anode plate and the ceramic nozzle are all fixed on the inner wall of the through hole.

Optionally, the outer surface of the capacitor is wrapped with a buffer layer, and the capacitor includes any one of the following:

a circular oil-filled capacitor, an upright oil-filled capacitor, or a dry capacitor.

The invention has the following beneficial effects: the resistance of a main discharge loop can be reduced, and meanwhile, the shape of an accelerating flow channel is improved by arranging the step type nozzle liquid, so that low-speed neutral gas generated by delayed gasification of the propellant can obtain higher speed, and the performance of the pulse plasma thruster is improved.

Drawings

FIG. 1 is a schematic structural diagram (one) of a pulsed plasma thrust unit (not shown in the schematic view of the entire box) according to an embodiment;

FIG. 2 is a schematic structural diagram of a pulsed plasma thrust apparatus according to another embodiment (II);

FIG. 3 is an enlarged view of portion A of FIG. 2;

FIG. 4 is a schematic structural view (III) of a pulsed plasma thrust unit according to another embodiment;

FIG. 5 is a schematic diagram of a ceramic nozzle of a pulsed plasma thrust unit according to another embodiment;

fig. 6 is a schematic diagram of a propellant track in a pulsed plasma thrust unit according to another embodiment.

10, a box body; 11. a screw; 12. a connecting strip; 13. a bell mouth; an insulating block; 30. a propellant track; 31. working medium; 32. a constant force spring retainer; 33. a first insulating plate; 34. a constant force spring thruster; 40. a rear metal plate; 50. a circuit box; 60. installing a station; 71. a cathode plate; 711. a threaded hole; 72. an anode plate; 73. a propellant channel; 74. and (3) a ceramic nozzle.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

FIG. 1 is a schematic structural diagram (one) of a pulsed plasma thrust unit (not shown in the schematic view of the entire box) according to an embodiment; FIG. 2 is a schematic structural diagram of a pulsed plasma thrust apparatus according to another embodiment (II); FIG. 3 is an enlarged view of portion A of FIG. 2; FIG. 4 is a schematic structural view (III) of a pulsed plasma thrust unit according to another embodiment; FIG. 5 is a schematic diagram of a ceramic nozzle of a pulsed plasma thrust unit according to another embodiment; fig. 6 is a schematic diagram of a propellant track in a pulsed plasma thrust unit according to another embodiment.

The embodiment of the application provides a pulse plasma thrust device, and the device includes: a propulsion fixing device; the anode plate 72 and the cathode plate 71 are fixed on the propulsion fixing device and are arranged oppositely and in parallel; the spark plug is fixed on the cathode plate 71 and used for discharging and ablating the working medium 31; a capacitor electrically connecting the anode plate 72 and the cathode plate 71; at least two ceramic nozzles 74 are arranged in a step shape and are arranged between the cathode plate 71 and the anode plate 72, the two ceramic nozzles are arranged in an opposite and flush manner, and a propellant channel 73 is formed by the ceramic nozzles 74, the cathode plate 71 and the anode plate 72 in an enclosing manner; the ceramic nozzle 74 is used for preventing electric leakage and creepage phenomena when the spark plug discharges and preventing plasma current scattering; the propellant track 30 is communicated with the propellant channel 73 and is used for moving the working medium 31; the constant force spring is fixed on the propellant track 30 through a spring fixing device and is used for continuously pushing the working medium 31 into the propellant channel 73 through the propellant track 30.

In this regard, the resistance of the main discharge circuit can be reduced, and at the same time, the shape of the acceleration flow channel is improved by providing the stepped nozzle liquid, so that the low-speed neutral gas generated by the delayed vaporization of the propellant can obtain higher speed, thereby improving the performance of the pulse plasma thruster.

Specifically, according to fig. 1 to 6, an embodiment of the present application provides a pulsed plasma thrust device, including: a propulsion fixture, an anode plate 72, a cathode plate 71, spark plugs, capacitors, ceramic jets 74, a propellant track 30, and a constant force spring.

Wherein, the anode plate 72 and the cathode plate 71 are both fixed on the propulsion fixing device and are arranged oppositely and in parallel; the spark plug is fixed on the cathode plate 71 and used for discharging and ablating the working medium 31; specifically, the cathode plate 71 is used for mounting a spark plug, the anode plate 72 and the cathode plate 71 form a loop, and the structure of the cathode plate 71 is designed according to the model of the spark plug, and the cathode plate 71 is fixed by a screw pair, so that the cathode plate 71 can be regarded as a cantilever beam.

And a capacitor electrically connecting the anode plate 72 and the cathode plate 71; in another embodiment, the outer surface of the capacitor is wrapped with a buffer layer, and said capacitor comprises any one of: a circular oil-filled capacitor, an upright oil-filled capacitor, or a dry capacitor.

In addition, the at least two ceramic nozzles 74 are arranged in a stepped manner. In one embodiment, the number of the ceramic nozzles 74 is two, and the two ceramic nozzles 74 are both disposed between the cathode plate 71 and the anode plate 72, and are disposed in a flush manner and face to face, and the ceramic nozzles 74, the cathode plate 71 and the anode plate 72 enclose a propellant channel 73; the ceramic nozzle 74 is used for preventing electric leakage and creepage phenomena when the spark plug discharges and preventing plasma current scattering;

in another embodiment, as shown in fig. 5, the ceramic nozzle 74 includes at least two insulating plates stacked in sequence, and the adjacent insulating plates are disposed in a step-like manner.

Of course, in another embodiment, the ceramic jets 74 may also be configured in a wedge shape; the end face of the ceramic nozzle 74 close to the electrode is designed as an isosceles right triangle and is machined with a 45-degree chamfer.

However, the ceramic nozzle 74 is positioned as close to the propellant surface as possible, so that the nozzle can ensure that the discharge channel between the cathode plate 71 and the anode plate 72 is not interfered, and the resistance of the main discharge circuit is greatly reduced.

The propellant track 30 is communicated with the propellant channel 73 and is used for moving the working medium 31; the constant force spring is fixed on the propellant track 30 through a spring fixing device and is used for continuously pushing the working medium 31 into the propellant channel 73 through the propellant track 30.

Specifically, as shown in fig. 1-6, the primary function of the propellant track 30 is to carry propellant and the constant force spring thruster 34, and the size of the working fluid 31 can be set to 25 x 10 x 65mm, so to control the size of the propellant track 30, we set the internal size of the track to 30 x 11 mm. However, we need to ensure that when the working medium 31 is pushed by the spring, the working medium 31 will not be inclined or twisted, and ensure that the working medium 31 will not be jammed or the working medium 31 will not be ejected from the rail under the pushing of the spring, so we will indent the upper part of the rail to form a gap smaller than the width of the propellant.

However, since the shape of the rail is complicated, the rail is bent more, and the rail is not thick, a large amount of waste is generated and the processing difficulty is very high if the metal block is milled in the aspect of processing. Therefore, for the machining of the rail, only the sheet metal machining can be selected. Sheet metal machining is a cold machining process specially performed for sheet metal. In summary, sheet metal machining is selected for machining the rail, and bending cold machining is used for the cut metal plate.

The constant force spring is fixed to the propellant track 30 by a spring fixing device and is used for continuously pushing the working medium 31 into the propellant channel 73 through the propellant track 30.

In another embodiment, the cathode plate 71 and the spark plug are provided with a threaded hole 711, the axial direction of the threaded hole 711 is perpendicular to the anode plate 72, and the spark plug is in threaded fixed connection with the cathode plate 71 through the threaded hole 711.

In addition, in another embodiment, the pulsed plasma thrust apparatus further includes: the plasma jet nozzle comprises a box body 10, a plasma jet nozzle, a bell mouth 13 and a mounting framework, wherein the plasma jet nozzle is arranged on the box body 10 and is communicated with the propellant channel 73, and the plasma is jetted out through the plasma jet nozzle after flowing through the propellant channel 73; a bell mouth 13, a contraction mouth of the bell mouth 13 being fixed on the outer surface of the chamber body 10 and surrounding the outer circumference of the plasma jet port; and the mounting framework is fixed on the inner wall of the box body 10 and is used for fixing the propelling and fixing device.

In another embodiment, the mounting skeleton comprises: the device comprises a front metal plate, a rear metal plate 40 and a first insulating plate 33, wherein the front metal plate is fixed on the inner wall of the box body 10, and the upper part of the front metal plate is provided with an installation station 60 for installing the propelling fixing device; the rear metal plate 40 is fixed on the inner wall of the box body 10, a fixing groove is formed in the upper portion of the rear metal plate, the fixing groove is used for embedding the end portion, far away from the plasma jet orifice, of the propellant track 30, the rear metal plate 40 and the front metal plate are arranged in a flush mode, and a mounting station 60 used for clamping and fixing the capacitor is reserved between the rear metal plate and the front metal plate; a first insulating plate 33 is fixed to a side wall of the front metal plate facing the bell mouth 13, and an outer surface of the first insulating plate 33 is covered with a conductor material for electrically connecting the capacitor and the spark plug to form an electric circuit.

In another embodiment, the first insulating plate 33 further has an insulating material for preventing electrical leakage coated on an outer surface thereof, wherein the conductor material and the insulating material are spaced apart from the surface of the first insulating plate 33 by the same distance.

In another embodiment, the spring fixing device includes: a constant force spring holder 32 and a constant force spring thruster 34, wherein the constant force spring holder 32 is fixed on the end of the front metal plate far away from the capacitor and is used for fixing one end of the constant force spring; a constant force spring thruster 34 is fixed to the propellant track 30 for rolling the other end of the constant force spring.

In another embodiment, the front metal plate and the rear metal plate 40 are both provided with lightening holes and/or lightening grooves, so that the weight of the device is reduced and the material is saved.

In another embodiment, the push fixture includes: the propellant track comprises an insulating block 20 and a through hole, wherein the through hole is formed in the insulating block 20, and the axial direction of the through hole is parallel to the length direction of the propellant track 30; also, the cathode plate 71, the anode plate 72, and the ceramic nozzle 74 are fixed to the inner wall of the through-hole.

Specifically, in another embodiment, the present invention provides a pulsed plasma thrust device, comprising: the design of the spark plug, the cathode plate 71, the anode plate 72, the propellant track 30, the front metal plate, the rear metal plate 40, the constant force spring, the insulating plate, the insulating block 20, the working medium 31 and the shell (namely the box body 10).

The spark plug, a cathode plate 71 and an anode plate 72, wherein the cathode plate 71 is used for installing the spark plug, and the anode plate 72 and the cathode plate 71 form a loop. The structure of the cathode plate 71 needs to be designed according to the model of the spark plug, and the cathode plate 71 is fixed through a thread pair, so that strength and rigidity can be checked by regarding the cathode plate 71 as a cantilever beam. Meanwhile, finite element analysis is carried out on the cathode plate 71, a thread pair is fixed, 5N of load is added at the position of a spark plug, and finally stress analysis is observed, wherein the maximum stress is 1.44 multiplied by 106Pa at the position with the smallest sectional area.

The propellant track 30, whose main function is to carry propellant and constant force spring thruster 34, is also the part connecting the front and rear metal plates 40. Where the size of the existing working medium 31 is 25 x 10 x 65mm, the size of the propellant track 30 is controlled so we set the internal size of the track to 30 x 11 mm. However, we want to ensure that working medium 31 will not be inclined or twisted when working medium 31 is pushed by a spring (i.e., the constant force spring mentioned above), and that working medium 31 will not be jammed or will not be ejected from the track when pushed by the spring. This is also true of the constant force spring thruster 34, so to control not to pop up from the upper side, we indent the upper side of the track, creating a gap that is smaller than the propellant width. A three-dimensional model of the propellant track 30 is shown in figure 6.

However, since the shape of the rail (i.e., the propellant rail 30) is complicated, the rail is bent more, and the thickness of the rail is not large, a large amount of waste material is generated and the processing is difficult if the metal block is milled. Therefore, for the machining of the rail, only the sheet metal machining can be selected. Sheet metal machining is a cold machining process specially performed for sheet metal. In summary, sheet metal machining is selected for machining the rail, and bending cold machining is used for the cut metal plate.

The front metal plate and the rear metal plate 40, and the front metal plate and the rear metal plate 40 mainly play a role in fixing the whole device of the thruster, the capacitor, the circuit board and the spring thrust device are required to be fixed on the front metal plate and the rear metal plate, and the shell is also required to be fixed on the front metal plate and the rear metal plate 40, so that the load of the whole device is greatly required by the front metal plate and the rear metal plate. However, in order to better reduce the overall gravity of the thruster, lightening holes and grooves need to be added to the front metal plate and the rear metal plate 40, and the strength and rigidity of the metal plates need to be ensured. The main thing to be checked is the shear stress to which the screw and the threaded rod 11 are subjected. The shear strength condition is as follows

[τ]＝180×0.4＝72MPa

τ＝0.94Mpa

Θτ≤[τ]

The bolt meets the checking requirement.

Finite element analysis conditions: the metal plate is made of brass, the bottom surface of the metal plate is fixed, and the shearing force is added to the threaded connection part, and the total shearing force is 25N.

The constant force spring is mainly used for pushing the working medium 31 to continuously advance, and ensures that the spark plug can discharge and electrolyze the working medium 31 all the time. The propellant is pushed to advance by using a constant force spring, and the constant force spring is an elastic spring which is obtained by carrying out heat treatment on a steel strip, and the main material of the constant force spring is low-temperature-resistant metal, so that the constant force spring can be completely used in space. And the constant force spring also solves the problem that the propelling agent moves forward and the thrust is less, and can ensure that the propelling agent can be always subjected to the same thrust at any time, so as to ensure that the propelling agent can continuously move forward until the propelling agent is completely consumed.

Secondly, in order to push the propellant more conveniently, a constant force spring needs to be wound on a fixed pushing device, so that the propellant is pushed more conveniently, and a fixed pushing device is designed. One end of the constant force spring is coiled on the pushing device, the other end of the constant force spring is fixed on the front metal plate through a thread pair, and the pushing device is continuously driven through pulling force to enable the propellant to be pushed forwards.

The insulating block 20, the insulating block 20 being the main connecting member of the whole apparatus, is connected to the insulating block 20 by an insulating plate, a front metal plate, a propellant track 30, and the like. However, the strength and rigidity of the insulating block 20 are enough to ensure the bearing load of the thruster, so in order to better reduce the mass and volume of the whole device, the parts of the insulating block 20 which are not practically used are cut away, and the thrust efficiency is ensured.

Meanwhile, because the insulating material is difficult to process, particularly the depth of the cutting groove reaches 5mm at most, the structure of the insulating block 20 is adjusted, the depth of all the grooves is less than or equal to 5mm, and the depth of the grooves is less than 5 mm.

The working medium 31, also called propellant, 31 is a polytetrafluoroethylene material. The polytetrafluoroethylene is a high molecular polymer prepared by polymerizing polytetrafluoroethylene serving as a monomer.

The working medium 31 is processed into a cuboid shape, but the contact surface between the spring pusher and the working medium 31 is a point, but the contact surface has a small stressed area, so the stress applied to the spring pusher is large. Therefore, in order to reduce the stress, the surface of the working medium 31 contacted with the pusher is machined and cut into a piece, so that the contact surface of the working medium 31 and the pusher can be attached.

The insulating plates mainly comprise two insulating plates, one insulating plate is used for preventing electric leakage and creepage phenomena when the spark plug discharges, and the other insulating plate is used for connecting the capacitor and the spark plug to form a circuit.

The insulating plate (the layered insulating plate is the ceramic nozzle 74) is mainly responsible for preventing the occurrence of electric leakage and creepage. The structural design of the insulating plate and the layers is as follows: the whole thickness of thickening insulation board divides into the three-layer with the insulation board to set up certain ladder between every layer, the phenomenon that just so can be fine prevents that powerful electric arc from climbing on the insulating material surface. However, because of the high processing difficulty and high performance requirement, machinable ceramics are selected for processing.

The two insulating plates are mainly responsible for connecting the capacitor and the spark plug to form a circuit, so that a copper sheet needs to be pasted on the insulating plate, and the circuit is connected. The oil-immersed capacitor is fixed between the front metal plate and the rear metal plate 40, and is installed above the capacitor through threads to lead out two poles of the capacitor. And meanwhile, copper plates are adhered to two ends of the insulating plate, and wires are welded at the edges of the copper plates and connected with the control circuit. Therefore, the insulating plate is adhered with a copper sheet.

The shell is mainly responsible for the fixing and protecting functions of the thruster, and the bell mouth 13 shape is manufactured at the output position of the thruster, so that the thrust efficiency can be better improved. The size of the bell mouth 13 is designed to be 98mm of outer mouth and 60mm of inner mouth. We cut it out using a plain drawing and connect it at a certain location by bending and using rivets.

Meanwhile, the thickness of the shell is thinner, so that a sheet metal processing part is adopted, the whole size and the structure of the shell are designed, then the shell is unfolded, and a plane unfolding diagram is processed. Of course, the design of the housing also requires holes to be punched to fix the housing. The main stress position is the position behind the shell, although the shell has the supporting function of the bottom plate, the bolts of the shell on the side are still subjected to great force, so that the strength of the threads on the side needs to be checked, and the shear stress to which the bolts are subjected is mainly needed to be checked. The shear strength condition is as follows

The performance grade of the bolt is 3.6, the allowable tensile strength of the bolt is 300MPa, the allowable shear strength of the bolt is 180MPa, and the static load analysis is carried out on the bolt by adopting a reamed hole bolt and selecting steel as a material. The allowable shear stress was 0.4. The overall force of the bolt is 20N, and the number of the bolts is 8M 3 bolts. The calculation formula is thus as follows:

[τ]＝180×0.4＝72MPa

τ＝0.471Mpa

Θτ≤[τ]

the bolt meets the checking requirement.

Meanwhile, in order to connect the internal lead with an external power supply, the rear cover of the shell is provided with a mounting hole of the electric connector.

The invention discloses a mechanical device based on a pulse plasma thruster, which is mainly used for carrying a thruster circuit control module and constructing the integral structure of the thruster. Meanwhile, the device is mainly applied to controlling the position holding and the attitude control of the microminiature. The device includes: the device comprises an oil-immersed capacitor, a control circuit, a spark plug, a working medium 31, a propellant pushing module and a system framework.

The oil-immersed capacitor is used for storing and discharging energy of the circuit. The capacitor adopts an oil-immersed capacitor, and the oil-immersed capacitor comprises a circular capacitor and an upright capacitor. While circular is selected for use. Oil-filled capacitors have many characteristics: the cylindrical metal aluminum shell has small volume and light weight. The capacitor has excellent electrical property, small loss and good self-healing property; the pressure type explosion-proof device is arranged inside the device, and the use is safe and reliable. However, since the oil-filled capacitor has a large volume, it can be placed only at a lower position of the entire device and fixed by the front and rear metal plates 40. Because the shell of oily formula condenser is mostly metal material, so when fixed electric capacity, we need design a set of lantern ring and wrap up the both ends of condenser as far as possible, and the tight condenser of clamp is connected with preceding metal sheet, back metal sheet 40 through screw rod 11 simultaneously, has both reduced the possibility of condenser electric leakage like this, has also prevented on the way in the delivery, and the lid takes place the friction around condenser and the metal, has played the effect of better protection condenser. Since the capacitor is also connected to the entire circuit, the two poles of the capacitor are led out of the device to a lead wire, which is finally connected to a position where it can be connected to a spark plug.

The control circuit is mainly used for controlling the discharge frequency of the spark plug. The control circuit is installed by a screw 11 of M4 through the hole of the circuit box 50 and connected to the expanded connecting bar 12 of the metal back shell. Of course, for the fastening measure, we can use bolt fastening. However, in the process of aerospace delivery, a large amount of vibration can occur, so that the looseness prevention of the threads is particularly important. Friction locking is the most widely used locking method, which generates a positive pressure between the thread pairs that is not changed by an external force, so as to generate a friction force that can prevent the thread pairs from rotating relatively. This positive pressure can be achieved by axial or simultaneous two-way compression of the thread pairs. Such as an elastic washer, a double nut, a self-locking nut, a nylon insert locking nut and the like. The anti-loosening mode is convenient for disassembling the nut, but under the conditions of impact, vibration and variable load, the pretightening force of the bolt is reduced due to loosening, the lost pretightening force is slowly increased along with the increase of the vibration times, and finally the nut is loosened and the threaded connection fails. Thus for better relaxation and to prevent the back metal plate 40 and the circuit box 50 from coming into close proximity, causing wear. We use the double nut approach. Not only will play a role of anti-loosing, but also heightens the height of the circuit box 50.

The spark plug is used for instantly generating electric arc when a circuit discharges, electrolyzing propellant and generating plasma. Which is secured to the cathode plate 71 by a threaded pair. Meanwhile, the anode plate 72 and the cathode plate 71 are connected to the insulating plate through a screw pair.

And the propellant pushing module is used for pushing the working medium 31 to continuously advance and gradually ionize. In order to push the propellant more conveniently, a constant-force spring needs to be wound on a fixed pushing device, so that the propellant is more conveniently pushed, and a fixed pushing device is designed. One end of the constant force spring is coiled on the pushing device, the other end of the constant force spring is fixed on the spring fixer through a thread pair, the pushing device is continuously driven through pulling force, the propellant is pushed forwards, and meanwhile, the spring fixer is fixed on the front metal plate through threads to be stable.

The insulating block 20, the insulating block 20 being the main connecting member of the whole apparatus, is connected to the insulating block 20 by an insulating plate, a front metal plate, a propellant track 30, and the like. The insulating block 20 is connected with the front metal plate through a screw pair, and plays a role in fixing the insulating block 20. The propellant track 30 is secured behind the insulating block 20 by means of screw bolts. Meanwhile, the insulating block 20 reserves a channel of the working medium 31 and an installation position of an insulating plate, and the insulating plate can be fixed by adopting an interference fit or gluing method.

The insulating plate is mainly responsible for connecting the capacitor and the spark plug to form a circuit, so a copper sheet needs to be adhered on the insulating plate, and the circuit is connected. Different copper sheets are respectively stuck on the two sides of the insulating plate, so that the insulating plate is respectively connected with the cathode plate 71 and the anode plate 72 of the spark plug. In order to prevent the electric leakage, it is necessary to attach an insulating tape to a portion other than the copper sheet to prevent the electric leakage.

The connecting strips 12 mainly include two types: the first is connected at the left and right of the front metal plate; the second is left-right connection of the rear metal plate 40. Threaded holes are formed in the left and right sides of the front metal plate, and the connecting bar 12 and the front metal plate are fixed by screw connection. The rear connection bar 12 has the same screw hole as the front connection bar 12, and needs an M4 screw hole for connecting the M4 screw 11, the circuit box 50 on the rear metal plate 40 is connected by the screw 11, and the screw is fixed by the bolt.

The metal shell is mainly used for fixing and protecting the thruster. Since the overall structure of the housing is large, the housing is divided into four parts: a front cover, a bell mouth 13, a shell extension, a shell side edge and a rear cover.

The front cover and the bell mouth 13 are cut according to the development of the bell mouth 13, and the thin metal plates are bent and cold-processed, so that the four metal plates are riveted and fixed through rivets, and finally the bell mouth 13 is formed. Meanwhile, the position and the crease of the front cover are reserved, the horn mouth 13 is inserted into the square hole of the front cover, and the front cover is fixed through the rivet. While the front cover is reserved around

The aperture allows the front cover to be extended into connection with the rear housing.

And the shell is extended, and the shell is finally obtained by cutting and unfolding the picture and performing sheet metal processing. The preformed holes are connected with the side metal plates and the bottom plate.

The side shell is subjected to sheet metal processing through cutting and unfolding of the drawing, and finally obtained. Meanwhile, the front surface of the shell is properly bent, so that the thruster is controlled not to shake forwards and backwards. The reserved hole positions on the side edges are respectively connected with the front metal plate and the rear metal plate 40. The rear reserved hole is connected with the rear cover.

And the metal shell rear cover is cut according to a two-dimensional drawing, and the position for installing the electric connector is reserved below the metal shell rear cover. The metal plate is fixed with the side metal plate through screw bolt connection.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A pulsed plasma thrust device, the device comprising:

a propulsion fixing device;

the anode plate (72) and the cathode plate (71) are fixed on the propelling and fixing device and are arranged oppositely and in parallel;

the spark plug is fixed on the cathode plate (71) and used for discharging and ablating the working medium (31);

a capacitor electrically connecting the anode plate (72) and the cathode plate (71);

the ceramic nozzles (74) are arranged in at least two step-shaped arrangement and are arranged between the cathode plate (71) and the anode plate (72) in an opposite and flush manner, and the ceramic nozzles (74), the cathode plate (71) and the anode plate (72) enclose a propellant channel (73); the ceramic nozzle (74) is used for preventing electric leakage and creepage phenomena when the spark plug discharges and preventing plasma current scattering;

the propellant track (30) is communicated with the propellant channel (73) and is used for moving the working medium (31);

the constant force spring is fixed on the propellant track (30) through a spring fixing device and used for continuously pushing the working medium (31) into the propellant channel (73) through the propellant track (30).

2. The apparatus of claim 1, wherein the ceramic nozzle (74) comprises at least two insulating plates stacked in sequence, and wherein adjacent insulating plates are stepped.

3. The device according to claim 2, characterized in that the cathode plate (71) is provided with a threaded hole (711), the axial direction of the threaded hole (711) is perpendicular to the anode plate (72), and the spark plug is in threaded fixed connection with the cathode plate (71) through the threaded hole (711).

4. The apparatus of claim 3, further comprising:

a case (10);

the plasma jet orifice is arranged on the box body (10) and communicated with the propellant channel (73), and the plasma flows through the propellant channel (73) and then is ejected out through the plasma jet orifice;

a bell mouth (13), wherein a contraction opening of the bell mouth (13) is fixed on the outer surface of the box body (10), and the contraction opening surrounds the periphery of the plasma flow jet opening;

and the mounting framework is fixed on the inner wall of the box body (10) and is used for fixing the propelling and fixing device.

5. The apparatus of claim 4, wherein the mounting skeleton comprises:

the front metal plate is fixed on the inner wall of the box body (10), and the upper part of the front metal plate is provided with an installation station (60) for installing the propelling and fixing device;

the rear metal plate (40) is fixed on the inner wall of the box body (10), a fixing groove is formed in the upper portion of the rear metal plate, the fixing groove is used for being embedded into the end portion, far away from the plasma flow jet orifice, of the propellant track (30), the rear metal plate (40) and the front metal plate are arranged in a flush mode, and a mounting station (60) used for clamping and fixing the capacitor is reserved between the rear metal plate and the front metal plate;

and the first insulating plate (33) is fixed on the side wall, facing the bell mouth (13), of the front metal plate, and the outer surface of the first insulating plate (33) is wrapped with a conductor material for electrically connecting the capacitor and the spark plug to form a circuit.

6. The apparatus of claim 5, wherein the first insulating plate (33) is further coated with an insulating material for preventing leakage of electricity on an outer surface thereof, wherein the conductor material and the insulating material are spaced apart from a surface of the first insulating plate (33) by the same distance.

7. The device of claim 6, wherein the spring retainer device comprises:

a constant force spring holder (32) fixed to an end of the front metal plate remote from the capacitor and for holding one end of the constant force spring;

and the constant force spring thruster (34) is fixed on the propellant track (30) and is used for rolling the other end of the constant force spring.

8. The device according to claim 7, characterized in that the front metal plate and the rear metal plate (40) are provided with lightening holes and/or lightening slots.

9. The device of claim 8, wherein the advancing fixture comprises:

an insulating block (20);

the through hole is formed in the insulating block (20), and the axial direction of the through hole is parallel to the length direction of the propellant track (30); also, the cathode plate (71), the anode plate (72), and the ceramic nozzle (74) are fixed to the inner wall of the through-hole.

10. The apparatus of claim 9, wherein an outer surface of the capacitor is wrapped with a cushioning layer, and wherein the capacitor comprises any one of:

a circular oil-filled capacitor, an upright oil-filled capacitor, or a dry capacitor.

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