JP4941662B2 - One component thruster - Google Patents

Description

  The present invention relates to a one-component thruster that obtains thrust by ejecting a decomposition gas generated by a decomposition reaction of hydrazine.

  The one-component thruster described above is used to control the attitude of an artificial satellite or change the orbit in outer space. As such a one-component thruster, for example, a tank containing hydrazine and this tank Some chambers are filled with a catalyst layer that decomposes hydrazine supplied from a solenoid valve and an injector to generate decomposition gas, and a nozzle that obtains thrust by jetting the decomposition gas generated in this chamber. .

In this one-part thruster, a layer of catalyst particles having a particle diameter of less than 1 mm formed by supporting about 30% of iridium as a catalyst on alumina particles is used as a catalyst layer, and the chamber is opened from the tank through the injector by opening the solenoid valve. When hydrazine is supplied in pulses, the hydrazine comes into contact with the catalyst layer and undergoes a decomposition reaction, which is decomposed into high-temperature ammonia, nitrogen, and hydrogen gases, and thrust is generated by injecting these decomposition gases from the nozzle. It is what you get. When the decomposition of hydrazine is in a steady state, the decomposition reaction shown in Formula (1) occurs.
3N2H4 → 4 (1-x) NH3 + (2x-1) N2 + 6xH2
(Where x is a coefficient from 0 to 1) Equation (1)

  In such a one-pack thruster, when intermittent operation is repeated as in the attitude control of an artificial satellite, the catalyst particles themselves in the catalyst layer repeat thermal expansion and contraction, and are also subjected to impact due to generation of high-pressure gas. However, particularly in the portion of the catalyst layer located near the injector, that is, in the portion where the reaction occurs suddenly by direct exposure to hydrazine, the catalyst particles are worn and crushed. In addition to the formation of voids, the efficiency of the decomposition reaction is reduced, and fine particles generated by abrasion and pulverization of catalyst particles accumulate on the downstream part of the catalyst layer and the nozzle throat part, leading to a reduction in thrust due to an increase in pressure loss. There was a possibility that a bug would occur.

In order to avoid the occurrence of such problems, a one-part thruster equipped with a pressing mechanism that compresses the catalyst layer itself in order to reduce the voids generated in the catalyst layer due to wear and pulverization of the catalyst particles, or the catalyst layer in a lattice shape A one-component thruster having an integrated catalyst layer is proposed (see, for example, Patent Documents 1 and 2).
JP-A-11-82171 JP 2001-20808

However, considering the use of the former one-component thruster in a special environment, the pressing mechanism having a movable element such as a spring is disadvantageous in terms of reliability, and in addition, the number of parts increases. However, it is inferior in terms of cost.
On the other hand, in the latter one-component thruster, in order to secure an effective area (contact area with catalyst particles) necessary for hydrazine decomposition to obtain sufficient thrust, the catalyst layer should be formed in a fine grid pattern. However, it is extremely difficult to form a fine mesh lattice-like integrated catalyst layer while supporting a large amount of iridium, which is not practical.

  The present invention has been made paying attention to the above-described conventional problems, and is easy to manufacture and advantageous in terms of reliability and cost, as well as local collapse and wear of catalyst particles in the catalyst layer. As a result, it is an object of the present invention to provide a one-component thruster with excellent durability capable of suppressing the occurrence of problems such as a decrease in the efficiency of hydrazine decomposition reaction and a decrease in thrust.

The invention according to claim 1 of the present invention includes a chamber having a hydrazine introduction portion and filled with a catalyst layer that decomposes hydrazine introduced through the hydrazine introduction portion to generate a decomposition gas, and the decomposition caused in the chamber. In a one-part thruster equipped with a nozzle that obtains thrust by jetting gas, a hydrazine dispersion promoting portion is provided in the vicinity of the hydrazine introduction portion of the chamber, and inert particles made of a material that is inactive against decomposition of the hydrazine are provided . It is characterized in that the layer is configured as the hydrazine dispersion promoting portion, and the configuration of this one-component thruster is used as a means for solving the above-described conventional problems.

  In this one-component thruster, when hydrazine is introduced into the chamber from the hydrazine introduction part, the hydrazine proceeds to the catalyst layer via the hydrazine dispersion promoting part, and when the catalyst layer comes into contact with the catalyst layer, a decomposition reaction occurs, and hydrazine After a large number of pulse injections are repeated and the inside of the chamber is in a steady state, the decomposition reaction shown in the above formula (1) occurs and is decomposed into high-temperature ammonia, nitrogen, and hydrogen gases. The thrust is obtained by jetting the nozzle from the nozzle.

When hydrazine introduced into the chamber from the hydrazine introduction section passes through the hydrazine dispersion promoting section , that is, a layer of inert particles made of a material that is inactive against the decomposition of hydrazine, it is dispersed almost uniformly. from not localized and abrupt that the reaction occurs in the catalyst layer, thus, collisions collapse or wear between the catalyst particles is a result not occur, so that the can space the catalyst layer is avoided.

Furthermore, the one-component thruster according to claim 2 of the present invention has a configuration in which a mesh-shaped partition wall portion is provided between the catalyst layer and the hydrazine dispersion promoting portion.
Furthermore, the one-component thruster according to claim 3 of the present invention is configured such that a mesh-shaped partition wall portion is provided between the hydrazine introduction portion and the hydrazine dispersion promoting portion of the chamber.
In one solution thruster of the present invention, as described above, by providing the mesh-like partition portion on at least one of the upstream及beauty Downstream side of hydrazine dispersion promoting portion, the dispersibility of the adjustment of the hydrazine However, even if the length of the hydrazine dispersion promoting portion is changed within the range not exceeding the length of the catalyst layer, the dispersibility of hydrazine can be adjusted.

In one solution thruster according to claim 1 of the present invention, because has a structure as described above, without the complicated configuration, it is substantially uniformly dispersed hydrazine introduced into the chamber from hydrazine introduction part Rukoto Ri can der, as a result, failures or wear of the local catalyst particles in the catalyst layer can be prevented from occurring.
In other words, it is easy to manufacture and maintains the advantages in terms of reliability and cost, while suppressing the occurrence of problems such as reduced hydrazine decomposition reaction efficiency and reduced thrust. A very excellent effect that the life can be extended is also brought about.

Furthermore , since the one-component thruster according to the second and third aspects of the present invention has the above-described configuration, it has a very excellent effect that the hydrazine dispersibility can be adjusted.

Hereinafter, a one-component thruster according to the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a one-component thruster according to the present invention.
As shown in FIG. 1, this one-part thruster 1 includes a tank 2 containing hydrazine and an injector (hydrazine introduction part) 3, and decomposes hydrazine supplied from the tank 2 through the injector 3 to decompose gas. And a support bar 3a located on the tank 2 side of the chamber 5 mainly composed of a chamber 5 filled with a catalyst layer 4 for generating gas and a nozzle 6 for obtaining a thrust by ejecting the cracked gas generated in the chamber 5. An electromagnetic valve 7 is disposed between the feed tube 3 b constituting the injector 3 and the tank 2.

  In the chamber 5, the space between the upstream mesh for dispersing hydrazine (mesh-like partition wall portion) 8 disposed adjacent to the injector 3 and the downstream mesh 9 disposed near the nozzle 6 is a catalyst layer housing portion. 5A, an alumina packed layer (hydrazine dispersion promoting portion) 10 is provided in the vicinity of the upstream mesh 8 of the catalyst layer housing portion 5A, while the space between the downstream mesh 9 and the nozzle 6 is A cracking gas chamber 5B is provided.

In this case, the catalyst layer 4 is a packed bed of catalyst particles having a particle diameter of about 1 mm formed by supporting about 30% of iridium as a catalyst on alumina particles, while the alumina packed layer 10 is formed of inert alumina particles. It is a packed bed.
In this one-component thruster 1, when hydrazine supplied from the tank 2 is introduced into the chamber 5 through the injector 3 and the upstream mesh 8 in a pulsed manner by opening the electromagnetic valve 7, the hydrazine is contained in the catalyst layer housing 5A. When the decomposition reaction occurs by touching the catalyst layer 4 via the alumina packed layer 10 in the chamber 5 and the inside of the chamber 5 becomes a steady state, the decomposition reaction of the formula (1) occurs, and the high temperature ammonia, nitrogen and hydrogen Thrust is obtained by injecting these decomposed gases, which are decomposed into the respective gases and maintained at a high pressure in the decomposed gas chamber 5B, from the nozzle 6.

  When the hydrazine introduced into the chamber 5 through the injector 3 passes through the alumina packed layer 10 which is a hydrazine dispersion promoting portion, the hydrazine is dispersed almost uniformly. Therefore, no collapse or wear due to collision between the catalyst particles does not occur, and the formation of a space in the catalyst layer 4 is avoided.

In other words, the one-component thruster 1 is easy to manufacture and maintains the advantages in terms of reliability and cost, while reducing the efficiency of the hydrazine decomposition reaction, and the fine particles generated by the collapse or wear of the catalyst particles are removed from the catalyst layer. In addition, it is possible to prevent the thrust from being deposited on the downstream portion of the nozzle or the nozzle throat portion, and the life can be extended.
Further, in this one-part thruster 1, since the packed layer of inert alumina particles is the alumina packed layer 10 which is a hydrazine dispersion promoting portion, the dispersibility of hydrazine can be improved with a simple configuration. Since the upstream mesh 8 for dispersing hydrazine is disposed adjacent to the injector 3, it is possible to adjust the dispersibility of hydrazine.

In one-pack thruster 1 according to this embodiment, although the alumina filler layer 10 formed by filling the alumina particles of the inert and hydrazine dispersion enhancing section, as a reference, an example example, inert alumina to degradation hydrazine the catalyst layer 4 of the catalyst particles having a particle size of less than 1mm comprising iridium as a catalyst is about 30% on the particles, or with hydrazine dispersion promoting portion a packed bed of reduced catalyst particles supported amount of the catalyst, in packed bed of the catalyst loading of less catalyst particles may or gradually increasing the amount of catalyst supported as the injector 3 of the chamber 5 towards the catalyst layer 4.

Further, in the one-component thruster 1 according to this embodiment, the alumina filling layer 10 filled with inert alumina particles is used as the hydrazine dispersion promoting portion. For reference, a material that is inactive against hydrazine decomposition is also used. It may be a hydrazine dispersion promoting portion inert porous body consisting of, this time, with respect to the decomposition of hydrazine inert inert porous body consisting of the material of less quantity than the catalyst particles in the catalyst layer 4 may be contained catalyst may interest was gradually increased as the content thereof extending from the injector 3 of the chamber 5 to the catalyst layer 4.

Various ceramics having sufficient strength such as zirconia can be used as an alternative material for alumina.
Further, in the one-component thruster 1 according to this embodiment, the upstream mesh 8 for hydrazine dispersion is disposed adjacent to the injector 3, but as shown in FIG. The mesh-shaped partition wall 18 may be provided between the catalyst layer 4 and the alumina packed layer 10 which is a hydrazine dispersion promoting part.

  Furthermore, in the one-component thruster 1 according to this embodiment, hydrazine is diffusely supplied from the tip of one feed tube 3b constituting the injector 3, but the present invention is not limited to this. A shower head may be attached to the tip of 3b to supply hydrazine separately from a plurality of locations, and a head space may be provided between the injector 3 and the hydrazine dispersion promoting portion.

  Note that the configuration of the one-component thruster according to the present invention is not limited to the configuration of the above-described embodiment.

It is a section explanatory view showing one embodiment of the one liquid thruster concerning the present invention. It is a section explanatory view showing other embodiments of the one liquid thruster concerning the present invention.

Explanation of symbols

1 One-component thruster 3 Injector (hydrazine introduction part)
3a Support rod 3b Feed tube (injector)
4 Catalyst layer 5 Chamber 6 Nozzle 8 Upstream mesh (mesh partition)
10 Alumina packed bed (hydrazine dispersion promoting part)
18 Mesh partition

Claims (3)

A chamber having a hydrazine introduction section and filled with a catalyst layer that decomposes hydrazine introduced through the hydrazine introduction section and generates a decomposition gas;
In a one-component thruster equipped with a nozzle that obtains thrust by ejecting the cracked gas generated in this chamber,
In the vicinity of the hydrazine introduction part of the chamber, a hydrazine dispersion promoting part is provided ,
A one-component thruster characterized in that a layer of inert particles made of a material inert to the decomposition of hydrazine is used as the hydrazine dispersion promoting portion . The one-component thruster according to claim 1, wherein a mesh-shaped partition wall portion is provided between the catalyst layer and the hydrazine dispersion promoting portion. 3. The one-component thruster according to claim 1, wherein a mesh-like partition wall is provided between the hydrazine introduction part and the hydrazine dispersion promoting part of the chamber.

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