JP3688749B2 - Rocket motor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a rocket motor used for orbit correction or attitude control of a flying object or an artificial satellite.
[0002]
[Prior art]
For flying objects, artificial satellites, etc., orbit control for guiding them to the target position or attitude control for flying in the attitude specified for the target position is performed remotely or automatically. .
[0003]
The propulsion unit used for the above trajectory correction and attitude control is an ion rocket that ejects ions to obtain thrust, an arc jet that heats working gas with an arc and accelerates it by a nozzle mechanism to obtain thrust (also called an arc rocket) ), And chemical rockets that obtain thrust by burning solid propellant or liquid propellant and ejecting combustion gas from a nozzle.
[0004]
Electric rockets have a large specific thrust but a small thrust itself, and in order to obtain a large thrust, the entire device including the power source must be expanded. In this case, it is used for those that are excessively heavy and require a large thrust. There is a problem that it cannot be done.
[0005]
A chemical rocket using solid propellant can stably obtain a large thrust, but cannot be interrupted once it is activated. For this reason, when many orbit corrections and attitude control are required, a large number of small rockets must be prepared, and there is a limit to the arrangement of these, and the structure must be complicated. There is a problem.
[0006]
In chemical rockets using liquid propellants, large thrust can be obtained many times by operating the valve, but as the propellant is liquid, it freezes at low temperatures and evaporates at high temperatures as the temperature changes. It is not easy to handle such as generating high pressure. Furthermore, there is a risk of leakage if it is loaded in the rocket motor for a long period of time, and the pipes, valves, tanks, etc. are heavy and complex, so they are used as small rockets used for orbit correction and attitude control. There is a problem that it is difficult.
[0007]
In order to solve the above-mentioned problems, a rocket motor is proposed in which a solid fuel and an oxidant that generates an oxidizing gas by heating are arranged separately, and the solid fuel and / or oxidant is decomposed and vaporized by electric heating to perform a combustion reaction. (JP-A-6-288302) has been studied.
[0008]
[Problems to be solved by the invention]
In the technique disclosed in JP-A-6-288302, a combustion chamber is mainly provided in the solid fuel. Therefore, when arc discharge is used as a heat source, the arc does not reach the combustion chamber and the combustion reaction is incomplete. There is a problem that the combustion may not be interrupted even under conditions where the combustion is interrupted originally when the power is cut off, and the reliability is insufficient.
[0009]
An object of the present invention is to provide a rocket motor capable of generating a large thrust remotely and reliably many times.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, a rocket motor according to the present invention separately disposes a solid fuel and an oxidant that generates an oxidizing gas when heated, and decomposes and vaporizes the solid fuel and / or the oxidant by electric heating to cause a combustion reaction. In the rocket motor, the solid fuel is disposed in one of the discharge spaces, the oxidant is disposed in the other, and the gas outflow hole leading to the nozzle is provided.
[0011]
In the rocket motor, it is preferable to provide an extrusion mechanism for extruding one or both of the solid fuel and the oxidant in the discharge space direction.
[0012]
[Action]
In the rocket motor, when a discharge space is provided in the interior, a solid fuel is disposed in one of the discharge spaces and an oxidant is disposed in the other, and an electric current is applied to cause arc discharge in the discharge space, the solid fuel and the oxidant are Heated by the arc, combustible gas is generated from the solid fuel and oxidizing gas is generated from the oxidant, and a combustion reaction occurs in the discharge space. The combustion gas generated at this time is discharged from the nozzle to the outside through a gas outflow hole provided in the discharge space to generate thrust.
[0013]
Further, when the energization is interrupted, the combustion gas is immediately released from the gas outflow hole provided in the discharge space, and the combustion surface is rapidly cooled. For this reason, the solid fuel and the oxidant are cooled, and the combustion can be interrupted with high reliability. That is, in the technique disclosed in Japanese Patent Laid-Open No. 6-288302, a combustion chamber is provided in the solid fuel or the oxidizer, so that the heat at the time of combustion remains in the combustion chamber and the combustion continues even when the energization is cut off. There was something to do. However, according to the present invention, the interruption of combustion can be performed with high reliability by combining the discharge space and the combustion chamber and providing a gas outflow hole in the discharge space to assist heat dissipation.
[0014]
Since the surface of the solid fuel and oxidant facing the discharge space moves away from the discharge arc as it burns, the discharge space gradually increases, and the energy of the discharge arc cannot be used effectively for the combustion reaction. May become unstable, or the discharge space will become larger and the heat transfer area will increase, resulting in an increase in heat capacity and heat storage, which will cause the solid fuel and oxidant to continue to decompose and energize Even if the operation is stopped, the combustion may not be interrupted. These have a greater effect as the length of the solid fuel or oxidizer increases. This problem can be solved by providing an extrusion mechanism that automatically pushes the burned length of one or both of the solid fuel and the oxidizer toward the discharge arc.
[0015]
In addition, although there is an electrode for discharge in arc discharge, this electrode is heated at the time of discharge, and even if the discharge is interrupted, solid fuel and oxidizer may continue to decompose due to the residual heat of the electrode. In such a case, for example, when it is necessary to lengthen the discharge time, it is preferable to arrange a heat insulating material for thermally blocking between one or both of the solid fuel and the oxidant and the electrode.
[0016]
The solid fuel is not limited as long as it is composed of a component that generates a combustible gas when heated by an arc and stops generation of the combustible gas when heating is interrupted. However, when ordinary plastics are used or decomposition is desired to be promoted, it is preferable to mix the oxidant powder to the extent that it does not have self-combustibility.
[0017]
The oxidizing agent is not limited as long as it is composed of a component that decomposes when heated, generates an oxidizing gas such as oxygen or halogen gas, and stops decomposition when heating is interrupted. For example, a molded body containing ammonium perchlorate, ammonium nitrate, polytetrafluoroethylene or the like as a main component, and a single molded body of these or a small amount of a binder added thereto is used.
[0018]
【Example】
A first embodiment of a rocket motor according to the present invention will be described below with reference to FIG.
[0019]
The main body 1 of the rocket motor has an energization side member 1a and a nozzle side member 1b. In the present embodiment, the energization side member 1a and the nozzle side member 1b are arranged with an angle of 180 degrees, but this is not necessarily limited to this angle, and the arrangement may be made with an angle other than 180 degrees. good.
[0020]
An annular electrode 5 connected to a conductive part 27 is attached to the energizing side member 1a via an insulator 21, and a nozzle 8 is attached to the nozzle side member 1b by a nozzle retainer 24 and a plurality of bolts 22. A gas outflow hole 7 is formed at a position facing the nozzle 8 of the annular electrode 5.
[0021]
The solid fuel 2 is disposed inside the main body 1 while being attached to the presser plate 23, and the presser plate 23 is fixed to the main body 1 by a plurality of bolts 22. In this way, the free end of the solid fuel 2 fixed to the main body 1 is fitted into the inner periphery of the annular electrode 5.
[0022]
The oxidizer 3 is disposed inside the main body 1 in a state of being fitted into a rod-like electrode 6 attached to the press plate 26 via an insulating tube 25, and the press plate 26 is fixed to the main body 1 by a plurality of bolts 22. ing.
[0023]
When the solid fuel 2 and the oxidant 3 are fixed to the main body 1 as described above, a discharge space 4 is formed between the surface of the solid fuel 2 and the surface of the oxidant 3. As the solid fuel, a molded body containing 30% to 70% ammonium perchlorate using polybutadiene as a binder was used. Further, as the oxidant 3, a pressure molded body of ammonium perchlorate alone, a polytetrafluoroethylene molded body, and a compression molded body in which 5% to 30% of polytetrafluoroethylene as a binding component was mixed with ammonium perchlorate were used. .
[0024]
The annular electrode 5 and the rod-shaped electrode 6 are arranged so that arc discharge is possible in the discharge space 4 when energized. The annular electrode 5 is configured to function as an anode, and the rod-shaped electrode 6 is configured to function as a cathode. A DC power source and a high frequency power source (not shown) are connected in parallel to these electrodes 5 and 6. These power sources can be adjusted in current and voltage, and can be adjusted so that a stable arc can be obtained and necessary energy can be supplied. The DC power source and the high-frequency power source are used for radiating required arc energy and starting the arc, respectively.
[0025]
In the rocket motor configured as described above, when the annular electrode 5 and the rod-shaped electrode 6 are energized, arc discharge occurs in the discharge space 4, and the solid fuel 2 is decomposed by the arc discharge energy to generate combustible gas. The oxidizing agent 3 is also decomposed to generate oxidizing gas. The generated gas burns in the discharge space 4 under the high temperature of the arc discharge and becomes a high-temperature combustion gas and is discharged from the nozzle 8 through the gas outflow hole 7. When the energization of the annular electrode 5 and the rod-like electrode 6 is stopped, the decomposition of the solid fuel 2 and the oxidant 3 is interrupted, and the generation of each gas is eliminated.
[0026]
Next, a second embodiment of the rocket motor according to the present invention will be described with reference to FIG.
[0027]
In this embodiment, if the discharge space 4 becomes larger as the solid fuel 2 and the oxidizer 3 become shorter due to combustion, the arc discharge energy becomes ineffective, and even if the energization is stopped due to heat accumulation in the discharge space 4, the gas This solves the problem that the generation may not be interrupted, and is advantageous when applied to a rocket motor using a solid fuel 2 and an oxidant 3 having a long length. In this embodiment, the gas generation mechanism by the arc is basically the same as that of the first embodiment. For this reason, the same parts as those in the first embodiment and the parts having the same functions are denoted by the same reference numerals, description thereof is omitted, and only different points will be described.
[0028]
A chamber P communicating with the discharge space 4 is formed between the solid fuel 2 and the holding plate 23 by the gas flow path 32. In this chamber P, an extrusion plate 31 contacting the end surface of the solid fuel 2, the holding plate 23 and the extrusion plate A coil spring 30 is provided between the plates 31 to urge the extruded plate 31 and the solid fuel 2 in the direction of the discharge space 4. These members constitute an extrusion mechanism 9 for the solid fuel 2. A heat insulating material 33 is disposed between the outer periphery of the solid fuel 2 and the annular electrode 5 to prevent the heat of the annular electrode 5 from being transmitted to the solid fuel 2 and smoothly move the solid fuel 2 in the direction of the discharge space 4. It is slidably covered so that it can be extruded.
[0029]
The extrusion mechanism 10 for the oxidant 3 is configured in the same manner as the extrusion mechanism 9 for the solid fuel 2. That is, a chamber Q that is electrically connected to the discharge space 4 is formed by the gas flow path 36 between the oxidant 3 and the pressing plate 26, and the chamber Q has an extrusion plate 34 that contacts the end surface of the oxidant 3, and the pressing plate 26. A coil spring 35 is provided between the pusher plate 34 and the pusher plate 34 to urge the pusher plate 34 and the oxidant 3 toward the discharge space 4. A heat insulating material 37 is disposed between the outer periphery of the oxidant 3 and the annular electrode 5 to prevent the heat of the annular electrode 5 from being transmitted to the oxidant 3. The oxidant 3 is slidably covered with a heat insulating material 37 and an insulating tube 25 so as to be smoothly pushed in the direction of the discharge space 4.
[0030]
In the extrusion mechanisms 9 and 10 configured as described above, combustion gas is introduced from the gas flow paths 32 and 36 into the chambers P and Q, and the pressure is essentially equal to that of the discharge space 4. For this reason, the urging force of the coil springs 30 and 35 always acts to push the solid fuel 2 and the oxidant 3 in the direction of the discharge space 4, so that the discharge space 4 is kept constant even if the solid fuel 2 and the oxidant 3 become shorter. It is possible to maintain.
[0031]
As the heat insulating materials 33 and 37, a composite material molded body of phenol resin is used.
[0032]
【The invention's effect】
As described above, in the rocket motor according to the present invention, when the electrode is energized, thrust is generated on the opposite side of the nozzle, and orbit correction or attitude control of the flying object or satellite can be performed. The energization command can be easily performed remotely.
[0033]
By using the combustion chamber also as the discharge space, it can be designed so that the arc can easily come into contact with the combustion surface, and the combustion reaction can be stabilized. That is, in this type of rocket motor, it is essential to interrupt the combustion. In the conventional method, since the combustion chamber is provided in the solid fuel or the oxidant, the heat at the time of combustion remains in the combustion chamber, and the combustion may continue even when the energization is cut off. However, in the present invention, the discharge space is also used as a combustion chamber, and gas discharge holes are provided in the discharge space to promote heat dissipation, whereby combustion can be interrupted with high reliability.
[0034]
By extruding the solid fuel and the oxidant in the direction of the discharge space by the extrusion mechanism, the discharge space can be maintained constant regardless of the progress of combustion, and the reliability with respect to combustion and combustion interruption can be improved. That is, since the surface of the solid fuel and the oxidant facing the discharge space moves away from the discharge arc as it burns, the discharge space gradually increases, and eventually the arc discharge energy cannot be used effectively. In addition, there is a risk that the discharge space becomes larger and heat is stored, and the solid fuel and the oxidant may continue to be decomposed due to this heat storage. Reliability can be maintained.
[Brief description of the drawings]
FIG. 1 is a sectional view of a rocket motor according to a first embodiment.
FIG. 2 is a sectional view of a rocket motor according to a second embodiment.
[Explanation of symbols]
P, Q chamber 1 Main body 1a Current-carrying member 1b Nozzle-side member 2 Solid fuel 3 Oxidant 4 Discharge space 5 Annular electrode 6 Rod electrode 7 Gas outflow hole 8 Nozzle 9, 10 Extrusion mechanism
21 Insulator
22 volts
23, 26 Presser plate
24 Nozzle retainer
25 Insulation tube
27 Conductive parts
30, 35 Coil spring
31, 34 Extruded plate
32, 36 Gas flow path
33, 37 Insulation

Claims (2)

In a rocket motor that disposes solid fuel and an oxidant that generates oxidizing gas by heating separately, and decomposes and vaporizes the solid fuel and / or oxidant by electric heating, a solid fuel in one of the discharge spaces And a gas outflow hole leading to the nozzle. The rocket motor according to claim 1, further comprising an extrusion mechanism for extruding one or both of the solid fuel and the oxidant in the direction of the discharge space.

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