RU2592599C1 - Method for making composite solid propellant charges - Google Patents

Abstract

FIELD: rocket construction.

SUBSTANCE: invention relates to production of rocket vehicles, particularly to making charges of composite solid propellant (CSP). Method for making charge of composite solid propellant involves successive mechanical mixing of oxidiser and combustible binder mixture based on polymer with plasticiser, metallic fuel, and process additives, and then batch filling up prepared fuel mixture into housing. Before mixing with plasticiser and other components, methyl polyvinyl tetrazolium polymer Included in composition of combustible binder, preliminary dried at temperature 100 to 140 °C to constant weight of polymer. In one particular case, drying polymer is carried out under vacuum at temperature 20 to 100 °C.

EFFECT: method provides minimum gas release from fuel, thereby physical and chemical stability of charge is provided for entire warranty shelf life.

1 cl, 3 tbl, 4 ex

Description

The invention relates to the field of production of rocket technology, namely to the manufacture of charges of mixed solid rocket fuel (SRTT), which can be equipped with rocket engines.

The composition of modern high-energy SRTT includes components based on nitroesters. The provision of mechanical characteristics and warranty periods for the storage of such fuels is complicated by the processes of increased gas evolution of the components of the active fuel-binding agent. The prior art method for the manufacture of charges SRTT according to the patent of the Russian Federation No. 2230052 (publication date 06/10/2004), comprising mixing the oxidizing agent with the prepared binder mixture with metal fuel, technological additives, followed by the discharge of the prepared fuel mass into the body.

The disadvantages of the described method include the impossibility of guaranteed obtaining the desired mechanical characteristics, the lack of control of the process of gas evolution from the fuel during storage.

Closest to the proposed technical solution and therefore adopted as a prototype, is a method of manufacturing mixed rocket fuel charges according to the patent of the Russian Federation No. 2534101 (publication date 11/27/2014) comprising sequential mechanical mixing of the oxidizing agent with the prepared mixture of combustible-binder with a plasticizer, metal fuel, technological additives and discharge of the prepared fuel mass into the body.

The disadvantages of the prototype include a low level of mechanical characteristics, an increased level of gas evolution from the fuel, which negatively affects the physicochemical stability of the fuel, leads to the formation of cracks and delaminations, and, as a result, reduces the warranty period of storage of the charge of the SRTT.

The objective of the proposed technical solution is to develop a method for manufacturing a charge of SRTT, which ensures minimal gas release from the fuel, as a result of which physicochemical stability of the charge is ensured during the entire warranty period of storage.

The problem is achieved by the proposed method for the production of mixed solid rocket charges, which includes sequential mechanical mixing of the oxidizer and the prepared mixture of a fuel-binder based on a polymer with a plasticizer, metal fuel, technological additives and portioned discharge of the prepared fuel mass into the body, while being part of the fuel -binder methylpolyvinyltetrazole polymer previously, before mixing with a plasticizer and other components, with a tub at a temperature of 100-140 ° C to a constant polymer mass.

In the particular case, the drying of methylpolyvinyltetrazole polymer is carried out under vacuum at a temperature of 20-100 ° C.

The proposed method differs from the prototype in that the methylpolyvinyltetrazole polymer (polymer) included in the combustible-binder polymer is dried before being mixed with a plasticizer and other components at a temperature of 100-140 ° C to a constant polymer mass.

By constant polymer weight is meant a polymer mass that does not change for 30 minutes during drying.

Pre-drying the polymer allows you to previously, before mixing it with the other components of the fuel, remove moisture and other volatile low molecular weight substances, as well as dissolved and encapsulated gases.

As a result, the completeness of gas removal increases, which reduces gas evolution from the fuel during storage and increases the physicochemical stability of the charge, which guarantees a predetermined charge storage period.

In the particular case, the polymer is dried under vacuum at a temperature of 20-100 ° C.

It is used if there is no technological ability to increase the drying temperature above 100 ° C, for example, when drying the polymer in a reactor with a water jacket.

Drying the polymer at temperatures above 140 ° C can lead to sintering and destruction of the polymer, and at temperatures below 20 ° C - to an unjustified increase in the duration of the process.

Comparative studies showed a steady improvement in the physico-chemical stability of the fuel manufactured by the proposed method, compared with known methods and prototype.

Below are the results of gas evolution studies before and after polymer drying. Table 1 shows the loss of volatile impurities during the drying of methylpolyvinyltetrazole polymer.

From table 1 it can be seen that as a result of polymer drying, the polymer mass decreases due to volatile impurities for different lots by 3.6-4.4% of the mass.

Table 2 shows the gas evolution rates of binders prepared on the starting and dried polymers.

From table 2 it is seen that as a result of drying the polymer, the rate of gas evolution of combustible binders decreased by 4-20%.

Thus, the proposed technical solution allows a simple way to significantly reduce gas evolution from the fuel and thereby increase the physico-chemical stability of the charge during the guaranteed storage period.

To illustrate the implementation of the method, examples of specific performance are given, it should be noted that the proposed method for producing charges of mixed rocket fuel, as shown by studies, does not depend on the nature of the oxidizing agent, which can be selected as all the currently known oxidizing agents used for mixed rocket solid fuels (e.g. ammonium perchlorate, potassium perchlorate, ammonium nitrate, ammonium dinitramide).

Example 1

The production of mixed solid rocket propellant charges is carried out by sequential mechanical mixing in a fuel-binder mixer based on a polymer and plasticizer, metal fuel, an oxidizing agent and processing aids at a temperature of 43 ° C and a residual pressure of 10 mm Hg. Art. Previously, methylpolyvinyltetrazole polymer (e.g., allylated methylpolyvinyltetrazole) is dried at a temperature of 140 ° C for 3 hours, followed by preparation of a fuel-binding agent, using nitroester plasticizer - nitroglycerin, at a residual pressure of 10 mm Hg. Art. and a temperature of 43 ° C until complete removal of the volatile solvent. Powdered aluminum is used as a metal fuel, TON-2 hardener (di-N-oxide-1,3-dinitrile-2,4,6-triethylbenzene) is used as a technological additive, and ammonium perchlorate is used as an oxidizing agent. The resulting fuel mass is poured in portions into the housing or mold.

Example 2

The manufacture of mixed solid rocket fuel charges is carried out by sequential mechanical mixing in a fuel-binder mixer based on a polymer and plasticizer, metal fuel, an oxidizing agent and processing aids at a temperature of 45 ° C at a residual pressure of 10 mm Hg. Art. Pre-methylpolyvinyltetrazole polymer is dried at a temperature of 100 ° C for 3 hours, followed by preparation of a combustible binder using a plasticizer - dinitrate-diethylene glycol at a residual pressure of 10 mm RT. Art. and a temperature of 45 ° C until complete removal of the volatile solvent. Aluminum metal diboride is used as metal fuel, and TON-2 hardener (di-N-oxide-1,3-dinitrile-2,4,6-triethylbenzene) is used as a technological additive, and potassium perchlorate is used as an oxidizing agent. The resulting fuel mass is poured in portions into the housing or mold.

Example 3

The production of mixed solid rocket propellant charges is carried out by sequential mechanical mixing in a fuel-binder mixer based on a polymer and plasticizer, metal fuel, an oxidizing agent and processing aids at a temperature of 48 ° C, a residual pressure of 10 mm Hg. Art. Pre-methylpolyvinyltetrazole polymer is dried at a temperature of 100 ° C for 1 hour at a residual pressure of 10 mm RT. Art. with the subsequent preparation of a combustible binder using a nitroester plasticizer - nitroglycerin, with a residual pressure of 10 mm RT. Art. and a temperature of 48 ° C until complete removal of the volatile solvent. As a metal fuel, aluminum powder is used. Hardener TON-2 (di-N-oxide-1,3-dinitrile-2,4,6-triethylbenzene) is used as a technological additive, and ammonium perchlorate is used as an oxidizing agent. The resulting fuel mass is poured in portions into the housing or mold.

Example 4

The manufacture of mixed solid rocket propellant charges is carried out by sequential mechanical mixing in a fuel-binder mixer based on a polymer and plasticizer, metal fuel, an oxidizing agent and processing aids at a temperature of 50 ° C, a residual pressure of 10 mm Hg. Art. Pre-methylpolyvinyltetrazole allylated polymer is dried at a temperature of 30 ° C for 10 hours at a residual pressure of 10 mm RT. Art. with the subsequent preparation of a combustible binder using a nitroester plasticizer - nitroglycerin, with a residual pressure of 10 mm RT. Art. until complete removal of the volatile solvent. As a metal fuel, aluminum diboride is used. Hardener TON-2 (di-N-oxide-1,3-dinitrile-2,4,6-triethylbenzene) is used as a technological additive, and ammonium dinitramide is used as an oxidizing agent. The resulting fuel mass is poured in portions into the housing or mold.

The obtained physicomechanical characteristics of the cured fuel mass are presented in Table 3, which shows that with the use of the dried polymer, the mechanical properties of the obtained samples are increased, and the gas evolution volume is steadily reduced.

The charges made in this way fully comply with the acceptance standards for physicochemical characteristics. Laboratory tests have confirmed their performance. Currently, the proposed method is being introduced into mass production.

Claims (2)

1. A method of manufacturing a charge of mixed solid rocket fuel, comprising sequential mechanical mixing of an oxidizing agent and a prepared mixture of a fuel-binder based on a polymer with a plasticizer, metal fuel, processing aids, and portioned discharge of the prepared fuel mass into a housing, characterized in that the fuel binder methylpolyvinyltetrazole polymer previously, before mixing with a plasticizer and other components, dried at a temperature of 100-140 ° C to a constant mass of polymer. 2. The manufacturing method according to claim 1, characterized in that the polymer is dried under vacuum at a temperature of 20-100 ° C.