JPS6264700A - Thrustor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thruster that provides thrust to an artificial satellite for controlling the orbit of the artificial satellite, for example.

[Conventional technology]

FIG. 3 is an explanatory diagram of a conventional catalytic thruster. For convenience of explanation, the following explanation uses hydrazine as a propellant. In Figure 3, (1) is piping, (2) is filter,
(3) is the propellant valve, and (4) is the feed tube.

+5+ (d decomposition chamber, (6) is nozzle, tts
Hasrot.

(l[9 is the injector, αη is the catalyst, and Oll is the mesh that prevents the catalyst from flowing out.

The conventional catalytic thruster is configured as described above, and the propellant, hydrazine, is pressurized to a predetermined pressure with pressurized gas and supplied through the piping fi+, and the propellant valve (3) is controlled by a drive signal. By opening the injector αe, which passes through the filter (2) and from the propellant valve (3) through the feed tube +41 to the decomposition chamber (5), brings the supplied hydrazine into contact with the catalyst <171. Make it into a spray state. Hydrazine in contact with the catalyst aη undergoes a decomposition exothermic reaction, producing ammonia.

It was decomposed into nitrogen and hydrogen gas, and thrust was obtained by discharging this decomposed gas into space from a nozzle (6).

[Problem that the invention seeks to solve]

The specific impulse of a thruster is theoretically proportional to the square root of the absolute temperature of the decomposed gas, and the higher the specific impulse, the smaller the amount of propellant required to be carried on the satellite.

In the conventional catalytic hydrazine thruster as described above, the temperature of the decomposed gas of hydrazine is limited to about 870°C to 980°C due to the chemical reaction energy of hydrazine by the catalyst, and the specific impulse is 220III! c to 24
There was a problem that it was limited to about 5wt.

The present invention was made to solve these problems, and therefore, it provides thermal energy to the decomposed gas of hydrazine using a heater to increase the kinetic energy of the particles of the decomposed gas.
[Means for solving the problem] The electrically heated thruster according to the present invention aims to obtain a higher specific impulse than the conventional catalytic hydrazine thruster. The cracked gas is passed through a heat exchanger with a built-in heat exchanger, and the electrical heating of the heater gives thermal energy to the cracked gas.

This system increases the kinetic energy of the decomposed gas particles before ejecting the decomposed gas from the nozzle into space. The heat exchanger for an electrically heated thruster according to the present invention includes a heater element spirally attached to a heater fixing rod inside a triple cylindrical heat exchanger having good heat transfer characteristics.

The cracked gas is supplied from a gas inlet pipe to one end of the triple-cylindrical external heat exchanger, and the heater is equipped with a triple-cylindrical external heat exchanger, an intermediate heat exchanger, an internal heat exchanger, and a heater element. The structure is such that it passes through a gap surrounded by a fixed rod and is discharged from the other end of the cylindrical shape to a nozzle.

[Effect]

In this invention, the decomposition gas of hydrazine supplied to the heat exchanger is heated by direct heating by a heater element and by radiant heating by a heater on the inner surface of an external heat exchanger of a triple-layered cylindrical heat exchanger.

This is done by surface heat generation from the inner and outer surfaces of the intermediate heat exchanger, the inner and outer surfaces of the internal heat exchanger, and the outer surface of the heater fixing rod that is conductively heated by the heater, so the heat generation surface area that comes into contact with the cracked gas is Since it can be made larger, the amount of heat exchange becomes larger, and the time during which the bicomponent gas is in contact with the heat generating surface becomes longer, so that more thermal energy can be given to the bicomponent gas. As a result, the 2 decomposition gas obtains a large amount of thermal energy and is brought into a high temperature state, increasing the kinetic energy of the 22 decomposition gas particles and improving the specific impulse of the thruster. For heating resistance heaters, the allowable temperature is 1650℃~
The cracked gas temperature can be raised to about 2000°0, and the specific impulse can be improved by 30 to 40% compared to conventional catalytic thrusters.

Further, in this invention, since the heat exchanger has the above-described structure, the heat exchange efficiency is good.

The electric power required for heater heating can be reduced. [Embodiment] FIG. 1 is an explanatory diagram showing an embodiment of the present invention. (
1) to (6) are completely the same as the conventional device described above. (7) is a gas introduction pipe, and (8) is a heat exchanger with a built-in heater.

FIG. 2 is a sectional view showing the basic structure of an embodiment of the heat exchanger (8), which is a feature of the present invention. (9) is a cylindrical external heat exchanger with good heat transfer characteristics.

αC is a cylindrical intermediate heat exchanger with good heat transfer characteristics;
αυ is a cylindrical internal heat exchanger with good heat transfer characteristics.
α2 is a heater fixing rod, and αJ is a heater element, which is spirally wound around the heater fixing rod α2.

I is the power lead wire of the heater, and the throat of the U-shaped nozzle L+31. The gas is sent by a gas inlet pipe (7) to a heat exchanger (8) and an external heat exchanger (9).

Intermediate heat exchanger Ql, internal heat exchanger αυ and heater fixing rod α
pass through the gap surrounded by 19 and is discharged to the nozzle (6). Heater element a3 electrically generates heat using electric power passed through lead wire α4.

Further, the heater fixing rod α2 in contact with the heater element α3 is heated by thermal conduction, and surface heating is performed on the decomposed gas. Further, the internal heat exchanger αυ is heated by the heater element α3 and the heater fixing rod α2 by thermal radiation, and surface heating is performed for the decomposed gas. Furthermore, the intermediate heat exchanger αe and the external heat exchanger (9) are heated by thermal conduction and thermal radiation, and surface heating is performed for each cracked gas, so that the heating surface area that the cracked gas comes into contact with is large, and the heat exchange time is Since the length can be increased, the amount of heat exchanged with the bicomponent gas can be increased. The decomposed gas is heated while passing through the heat exchanger (8) as described above, becomes high temperature, and is discharged into space from the nozzle (6).

Therefore, the specific impulse of the conventional catalytic hydrazine thruster can also be increased.

Incidentally, in the above embodiment, hydrazine was used as the propellant, but it goes without saying that other propellants that cause a chemical reaction with the catalyst may be used.

Moreover, the position of the throat housing 9 does not have to be on the cylindrical end face in the axial direction. Similarly, a similar operation can be expected even if it is provided on the cylindrical axis direction surface with the gas introduction pipe (7).

〔Effect of the invention〕

As explained above, this invention solves the gap between the heater fixing rod, in which the triple cylindrical external heat exchanger, intermediate heat exchanger, internal heat exchanger, and heater element with good heat transfer characteristics are spirally wound. Using a heat exchanger with a simple structure that allows gas to pass through, the propellant separated by the catalyst is efficiently electrically heated using a heater, and the 1st decomposed gas is brought to a high temperature, which increases the kinetic energy of the 2nd decomposed gas particles. Compared to catalytic thrusters, this has the effect of increasing specific impulse and reducing the amount of propellant required for satellites.

Furthermore, the above-mentioned heat exchanger of the present invention has a large catalytic heating area for one cracked gas, and also has a long heat exchange time, resulting in good heat exchange efficiency and the ability to save electric power for two heaters.

[Brief Description of the Drawings] Fig. 1 is an explanatory diagram of a thruster showing an embodiment of the present invention, Fig. 2 is an explanatory cross-sectional diagram showing the basic structure of an embodiment of a heat exchanger of the invention, and Fig. 3 The figure is an explanatory diagram of a conventional catalytic hydrazine thruster, in which (1) is the piping;
2) is a filter, (3) is a propellant valve, (4) is a feed tube, and (5) is a decomposition chamber. (6) is a nozzle, (7) is a gas introduction pipe, (8) is a heat exchanger, (9) is an external heat exchanger, CIG is an intermediate heat exchanger,
(ill is the internal heat exchanger, α2 is the heater fixing rod, Q
3 is the heater element, α4 is the lead wire, Kasumi is the throat, αe is the injector, Q7) is the catalyst, and a second is the mesh. Note that the same symbols in the two figures indicate the same or corresponding parts.

Claims (1)

[Claims] a decomposition chamber for catalytically decomposing a propellant, a cylindrical external heat exchanger, a cylindrical intermediate and internal heat exchanger located within the external heat exchanger, and a heater provided within the internal heat exchanger. A fixing rod, a heater element spirally wound at predetermined intervals in the axial direction of the heater fixing rod, and a heater element provided at one end of the heat exchanger and in a gap surrounded by the three heat exchangers and the fixing rod. An inlet for injecting the decomposed gas of the propellant obtained from the decomposition chamber, a throat provided on the other end of the heat exchanger facing a nozzle for discharging the decomposed gas to the outside space, and the heater element. a heat exchanger consisting of a lead wire for supplying electric power and causing the cracked gas to spiral through a gap surrounded by the three heat exchangers and the heater fixing rod and pass toward the nozzle side;
A thruster comprising: a nozzle that is provided facing the throat of the heat exchanger and discharges cracked gas from the heat exchanger to an external space.