JP2010216446A - Composite solid propellant and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite solid propellant and a method for manufacturing the same, positively relaxing the ununiformity of combustion speeds caused by an influence or the like from the other member in order to provide a constant combustion speed. <P>SOLUTION: In this method for manufacturing the composite solid propellant, uncured slurry 1 as propellant constituent material cures after being filled from the opening on the side of a nozzle into the casting space of a motor case 2 surrounded by a bottom and a cylindrical portion. The uncured slurry 1 is filled in a manner as to be dropped or continuously poured into the vicinity of the inner surface of the cylindrical portion of the motor case 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a composite solid propellant that mitigates nonuniformity in the combustion rate caused by the influence of other members and the like so as to obtain a constant combustion rate, and a method for producing the same.

  Solid rockets have the advantages of high reliability, long-term storage, and large initial acceleration and thrust. When the solid rocket propellant is a composite solid propellant, a direct filling method in which an uncured propellant slurry is poured directly into a motor case or a mold and cured in a stationary state is the main manufacturing method.

  In the end face combustion type composite solid rocket motor, a phenomenon in which the combustion speed in the vicinity of the inner surface of the motor case increases frequently due to the influence of other members or the like. This local increase in the combustion rate occurs under various conditions regardless of the composition of the propellant and the manufacturing method, but it is desired to improve the combustion so that the combustion proceeds uniformly.

  As an improvement method by the composition of the propellant for causing the combustion to progress uniformly, for example, a method of heating and melting after filling a uniform dry product composed of a thermoplastic elastomer, an oxidizing agent, and an additive is disclosed in Patent Document 1. Has been.

  In addition, for composite solid propellants, the mechanism by which the combustion rate near the inner surface of the motor case increases due to the influence of other members is not clear, and an active suppression method has not been established. This is the current situation.

JP-A-1-249955 (first page)

  However, the method described in Patent Document 1 has a problem that a thermoplastic elastomer is an essential component, that is, the binder component is limited to the thermoplastic elastomer, so that it cannot meet a wide range of requirements for composite solid propellants. It was.

  In addition, the conventional empirical method has a problem that minor changes that do not affect functions other than the combustion speed are not easy.

  Accordingly, an object of the present invention is to provide a composite solid propellant in which the nonuniformity of the combustion rate generated due to the influence from other members and the like is positively reduced so as to obtain a constant combustion rate, and a method for producing the same. It is to provide.

The present invention utilizes the relationship between the flow direction of the slurry or the shape of the lamination interface and the combustion speed in the propellant casting process, and the angle of the lamination interface shape of the slurry becomes steep as it goes to the motor center. By doing so, it has been found that the combustion speed in the central portion of the motor can be increased, and that medium-high combustion in an end face combustion type motor, described later, can be mitigated.
That is, in the method for producing a composite solid propellant according to the first aspect of the present invention, the uncured slurry as the propellant constituting material is opened in the casting space of the motor case surrounded by the bottom portion and the cylindrical portion. In the method for producing a composite solid propellant that hardens after filling from the part, uncured slurry is dropped or continuously injected into the vicinity of the inner surface of the cylindrical part of the motor case.

  The method for producing a composite solid propellant according to a second aspect of the present invention is characterized in that the composite solid propellant is a composite solid propellant for an end face combustion type composite solid rocket motor.

  The composite solid propellant of the third invention of the present invention is obtained by the method for producing a composite solid propellant of the first or second invention, and the obtained composite solid propellant has a laminated interface whose central axis is a motor case. It is characterized by being filled so as to be convex toward the nozzle part side.

  In the first aspect of the present invention, the uncured slurry is dropped or continuously injected into the vicinity of the inner surface of the cylindrical portion of the motor case to increase the combustion speed of the motor central portion, and the combustion surface is formed into a conical shape. Growth can be suppressed and nonuniformity in the combustion rate can be mitigated.

  In the second invention of the present invention, since the composite solid propellant is a composite solid propellant for an end-face combustion type composite solid rocket motor, the above effect, that is, the effect of alleviating unevenness of the combustion speed is particularly remarkable. Become.

  In the third invention of the present invention, the propellant is filled and cured so that the lamination interface between the uncured slurries is convex toward the nozzle part at the central axis of the motor case. As a result of having a combustion speed distribution opposite to the non-uniform combustion speed caused by the influence of the members, etc., the increase in the combustion area due to the non-uniform combustion speed is suppressed, and the constant combustion expected in the design stage Speed is obtained. The effect is particularly remarkable in the case of an end face combustion type composite solid rocket motor.

It is sectional drawing which shows the outline | summary of an end surface combustion type rocket motor. (A) And (b) It is sectional drawing explaining the non-uniform combustion generate | occur | produced with an end face combustion type rocket motor. It is sectional drawing which shows the lamination | stacking interface shape in the propellant of this invention. (A) Sectional drawing explaining the characteristic of lamination | stacking of uncured slurry, (b) It is sectional drawing which shows the lamination | stacking interface shape in the propellant obtained by dripping or continuously inject | pouring uncured slurry to the center part of a motor case. is there. (A) It is a perspective view which shows the lamination | stacking interface shape in an actual propellant, (b) The reproduction figure of the photograph which shows the cut surface of the propellant after hardening. 1 is a cross-sectional view showing a method for producing a propellant of the present invention in Example 1. FIG. FIG. 7 is a correlation diagram between the distance in the motor radial direction of the propellant and the combustion rate obtained by the method shown in FIG. 6 (correlation diagram showing the distribution of the propellant combustion rate). It is sectional drawing which shows the manufacturing method of the propellant in the comparative experiment 1. FIG. 9 is a correlation diagram between the distance in the radial direction of the propellant motor and the combustion speed obtained by the method shown in FIG. 8 (correlation diagram showing the distribution of the propellant combustion speed).

  The present invention relates to a method for producing a composite solid propellant that cures after filling a casting space of a motor case surrounded by a bottom portion and a cylindrical portion with an uncured slurry as a propellant constituent material from an opening on the nozzle portion side. A method for producing a composite solid propellant, preferably a method for producing an end face combustion type solid solid rocket motor, wherein uncured slurry is dropped or continuously injected into the vicinity of the inner surface of the cylindrical portion of the motor case. .

  The constituent material of the uncured slurry is not particularly limited in composition, but for example, an oxidant, a binder that also serves as a fuel, a curing agent or a crosslinking agent, a binder, a plasticizer, a combustion catalyst, a metal fuel, and vibration combustion. An inhibitor or the like is appropriately blended.

As shown in FIG. 1, the motor case 2 filled with the uncured slurry 1 has, for example, a single-opened cylindrical shape with a bottom attached to one end of the cylindrical portion, and the material thereof is, for example, metal or fiber reinforced plastic. Is used. In order to protect the motor case 2 from the temperature of the combustion gas, a heat insulating material may be applied to the inner surface of the cylindrical portion and the bottom portion of the motor case 2 in a covering state. Further, a primer may be applied to the surface of the motor case 2 or the heat insulating material in order to obtain an appropriate adhesive force with the propellant in which the uncured slurry 1 is cured. In addition, the motor case 2 may be provided with a mechanical structure necessary for the operation when the nozzle 3 is attached or used. There is also a solid rocket that does not directly cast uncured slurry into the motor case, but once casts the uncured slurry into a rubber container and incorporates the cured propellant into the motor case together with the rubber container. However, in this case, it goes without saying that this rubber container corresponds to the motor case referred to in the present application.
In addition, although the propellant which hardened the uncured slurry 1 is also denoted by the same reference numeral 1, the nozzle 3 is not attached at the manufacturing stage in which the uncured slurry 1 is cast and cured.

  As a specific example of the method of dropping or continuously injecting the uncured slurry to the vicinity of the inner surface of the cylindrical portion of the motor case, for example, a container filled with the uncured slurry and provided with an outlet of the uncured slurry is used. Installed in the upper part of the opening, the uncured slurry is dripped or continuously from the container by the dead weight or pressure of the uncured slurry in the vicinity of the inner surface of the cylindrical part of the motor case, for example, 20% of the diameter from the outer periphery of the motor case There is a way to inject. Here, the container installed in the upper part of an opening part may be combined with the mixing container provided with the outflow port of uncured slurry.

  Further, in order to eliminate bubbles in the uncured slurry filled in the motor case, the motor case is placed in a tank that has been scavenged to a high vacuum, and the outlet of the container of the uncured slurry is hermetically connected. In the case of a mold, the atmospheric pressure applied to the upper slurry liquid surface becomes a pressure source for pumping the uncured slurry. The uncured slurry once dropped or injected into the motor case flows and deforms due to its own weight and fills the motor case. A pipe or the like can be installed between the slurry outlet and dropping into the motor case, and the flow path of the uncured slurry can be adjusted arbitrarily.

  Furthermore, as a method of curing after filling with the uncured slurry, for example, a motor case or a container in which the uncured slurry is cast in a room or a heating tank controlled to a temperature and humidity suitable for curing is appropriately used. Although there is a method of standing for a period, etc., it is not particularly limited to this.

By adjusting the uncured slurry casting method as described above, the burning rate at an arbitrary position in the propellant can be increased or decreased.
In addition, variations in the casting method of the uncured slurry can provide a distribution of local combustion rates and broaden the design of the rocket motor. For example, it is possible to control the shape of the slurry lamination interface by changing the settlement point of the uncured slurry at the time of casting.

  Further, the uncured slurry 1 is dropped or continuously injected from the vicinity of the inner surface of the cylindrical portion of the motor case 2 to fill the stacked interface 6 between the uncured slurries 1 and 1 as shown in FIG. Although it can be filled so as to be convex toward the nozzle portion 3 side at the center axis of 2, this is performed using the following known characteristics.

The uncured slurry 1 is a mixture of an oxidizing agent, a binder that also serves as a fuel, a curing agent or a cross-linking agent, a binder, a plasticizer, a combustion catalyst, a metal fuel, a vibration combustion inhibitor, and the like. Therefore, when casting, it drops while intermittently or continuously overlapping the motor case 2 or the mold one by one.
At the place where the uncured slurry 1 is settled or folded, a laminated interface 6 between the uncured slurries 1 and 1 is generated, and this laminated interface 6 is pushed by the cast uncured slurry 1 after that, A laminated structure is formed. The shape of the formed laminated interface 6 varies depending on the casting method of the slurry 1, but as shown in FIG. 4A, there is a characteristic that the laminated interface 6 is horizontal in the vicinity immediately below the fixing point of the uncured slurry 1. is there.

When the uncured slurry 1 is dropped or continuously injected into the central part of the motor case 2, a laminated interface that is concave on the nozzle part 3 side at the central axis of the motor case 2 as shown in FIG. 6 shapes are obtained. On the other hand, when the uncured slurry 1 is dropped to the vicinity of the inner surface of the cylindrical portion of the motor case 2, the laminated interface 6 that protrudes toward the nozzle portion 3 on the central axis of the motor case 2 as shown in FIG. A shape is obtained.
These laminated structures are maintained even during the curing of the uncured slurry 1, and this laminated shape remains in the completed propellant 1 after curing. Therefore, in the propellant 1, it is empirically that the combustion rate decreases when the combustion proceeds in the direction crossing the laminated interface 6, and conversely the combustion rate increases when the combustion proceeds in the direction along the laminated interface 6. Known to.

[Example 1]
In order to confirm the dripping or pouring position of the uncured slurry 1 and the shape of the laminated interface 5 between the uncured slurries 1 and 1 formed thereafter, a box shape as shown in FIGS. 5 (a) and 5 (b) The uncured slurry 1 that was intentionally colored in a different color was sequentially dropped or injected from one side of the mold 8 and the cut surface after curing was observed. The propellant, that is, the component of the uncured slurry 1 before curing is composed of ammonium perchlorate, terminal hydroxyl group polybutadiene, a curing agent, a plasticizer, and the like. Is 80%, and the binder mainly composed of terminal hydroxyl group polybutadiene is 20%. Moreover, in order to visualize the laminated interface between uncured slurries, a small amount of iron oxide powder or carbon powder was added and colored. Uncolored or colored uncured slurry was dropped or poured into a box-shaped mold having an opening size of 50 mm × 120 mm and a height of about 120 mm as shown in FIG.
The resulting laminated interface shape between the uncured slurry 1 and 1 sinks at the dropping or pouring position of the uncured slurry 1 and moves upward as it moves away from the dripping or pouring position, and the angle is away from the dripping or pouring position. 5A, the left end, which is the wall surface in FIG. 5A, is considered to correspond to the central portion of the motor case 2 shown in FIG. 3, that is, the symmetrical boundary portion. The propellant 1 having the laminated interface shape shown in FIG. 3 is obtained by the method of dropping or injecting the slurry 1 near the inner surface of the motor case 2 shown in FIG.

An example of an actual casting method to the motor case 2 is shown in FIG. The propellant in this example, that is, the constituent components of the uncured slurry 1 before curing, is 68% ammonium perchlorate, 14% binder mainly composed of terminal hydroxyl group polybutadiene, and 18% aluminum powder.
The motor case 2 having an opening size of φ50 mm and a total length of 150 mm is installed with the opening facing upward in a vacuum chamber 9 that has been scavenged to a high vacuum, and fills the uncured slurry 1 on a pedestal 13 disposed across the motor case 2. The container 10 is coupled through the slurry outlet 11 with an airtight structure capable of maintaining a vacuum. Further, a branch portion (12) for guiding the uncured slurry 1 to the vicinity of the inner surface of the motor case 2 is provided between the slurry outlet 11 and the opening of the motor case 2. Although the structure of this branch part (12) can be considered variously, for example, as shown in FIG. 6, the branch container 12 having a structure in which holes are continuously provided at circumferential positions corresponding to the vicinity of the inner surface of the motor case 2, A method of directly connecting to the slurry casting port 11 is conceivable. In this embodiment, the uncured slurry 1 is pushed downward from the upper vessel 10 by atmospheric pressure and its own weight, and is guided to the branch vessel 12 through the slurry outlet 11. When the uncured slurry 1 is filled in the branch vessel 12, the uncured slurry 1 is dripped into the vicinity of the inner surface of the motor case 2 from the φ5 mm holes arranged at 20 locations in a circular shape of φ45 mm at the bottom of the branch vessel 12. Infused continuously. The slurry flow rate can be controlled by including a valve (not shown) provided at the slurry outlet 11.

  In the propellant in which the uncured slurry mainly composed of terminal hydroxyl group polybutadiene, ammonium perchlorate, and metal fuel used in the above examples was cured, the relationship between the slurry lamination interface shape and the burning rate was along the lamination interface. Since there is empirical knowledge that the combustion rate increases when the combustion progresses and conversely the combustion rate decreases when the combustion proceeds in the direction crossing the stacking interface, it has the stacking interface shape shown in FIG. The combustion speed in the length direction of the propellant 1 has the relationship shown in FIG. Such a distribution of the combustion speed has a high combustion speed at the center portion of the motor case 2 and has an effect of denting the center portion, so that it cancels out the convex conical shape generated by the non-uniform combustion shown in FIG. It is possible to keep the surface flat.

[Comparative Experiment Example 1]
As a comparative experimental example, in the casting method of Example 1 shown in FIG. 6, the uncured slurry 1 was dropped or injected directly from the slurry outlet 11 to the center of the motor case 2 without using the branch vessel 12. An example of the case will be described.
FIG. 8 shows a casting method of a comparative experimental example. Unlike the casting method of Example 1 in FIG. 6, the uncured slurry 1 is dropped from the outlet 11 of the upper container 10 directly into the center of the motor case 2 from the single hole of φ5 mm without passing through the branch container 12 or Injected. The shape of the motor case in this example is a cylinder with an opening φ50 mm and a total length of 150 mm, as in the previous embodiment. In this case, as already described, a slurry lamination interface shape that is concave on the nozzle part 3 side at the central axis of the motor case 2 shown in FIG. 4B is obtained.
And in the composite propellant comprised with the component similar to what was used by the casting to the actual motor case 2 in the said Example 1, distribution of the combustion rate shown in FIG. 9 is obtained. As a result of the distribution of the combustion speed shown in FIG. 9, the propellant in the center of the motor with the slow combustion speed is gradually left behind, and as a result, the medium-high combustion which is the solution of the present invention shown in FIG. 2 is generated. . The medium-high combustion shown in the problem to be solved by the invention is a phenomenon in which the cause has not been clarified due to the characteristics of the motor case member and the combustion region, and its active control is difficult. The meaning of the medium-high combustion generated by the casting shown in Comparative Experimental Example 1 is different in that it is actively controlled by the method provided by the present invention.

1 propellant (uncured slurry)
2 Motor case 3 Nozzle 4 Initial propellant surface 5 Propellant surface during combustion 6 Laminated interface between propellant slurries 7 Slurry flow direction 8 Mold 9 Vacuum tank 10 Propellant mixing container or container 11 Slurry outlet 12 Branch container 13

Claims (3)

  In a manufacturing method of a composite solid propellant that cures after filling an uncured slurry, which is a propellant constituent material, into a casting space of a motor case surrounded by a bottom portion and a cylindrical portion from an opening on a nozzle portion side, the uncured slurry In the vicinity of the inner surface of the cylindrical portion of the motor case.   2. The method for producing a composite solid propellant according to claim 1, wherein the composite solid propellant is a composite solid propellant for an end face combustion type composite solid rocket motor.   The composite solid propellant obtained by the method for producing a composite solid propellant according to claim 1 or 2 is filled so that the lamination interface is convex toward the nozzle part side at the central axis of the motor case. A composite solid propellant characterized by that.