JPH0725630B2 - Solid gas generator for ducted rocket engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a solid gas generating agent for a ducted rocket engine.

<Prior art> A ducted rocket engine normally burns a gas generant in the primary combustion chamber to generate a high-temperature fuel-rich gas, which is then introduced into the secondary combustion chamber and taken into the secondary combustion chamber. Since it is completely burned by air, it is possible to obtain a high thrust as compared with a normal rocket.

A component of a composite propellant is partially used as a solid gas generator for a ducted rocket engine, and a binder serving as a fuel and a binder, a metal powder serving as a metal fuel, and an oxidizer are the main components. As the binder used in the composite propellant, polybutadiene,
In addition to polyurethane and the like, a polyether having an azidomethyl group as a high energy binder (JP-A-62-26
5192) and the like, and aluminum, boron, etc. are used as the metal powder, and ammonium perchlorate, ammonium nitrate, nitramine, etc. are used as the oxidizer.

In a normal composite propellant, it is essential to contain a large amount of an oxidant in order to generate a large amount of gas at a high temperature. Therefore, when a normal composite propellant is used as the solid gas generator for the ducted rocket engine, most of the generated gas burns in the primary combustion chamber, so the gas introduced to the secondary combustion chamber has few combustion components, The engine performance cannot be fully exerted.

As a solid gas generating agent for a ducted rocket engine, it is necessary that the oxidant component has a composition with a large amount of fuel components within a range that does not hinder the combustion of the gas generating agent.

Therefore, a solid gas generating agent for a ducted rocket engine, which contains a large amount of metal powder such as aluminum, boron, or magnesium alloy which is an alloy of aluminum and magnesium, has been proposed as a metal fuel. (JP-A-59-92992 and JP-A-61-127692) The solid gas generating agents for ducted rocket engines specifically disclosed in these publications contain 40 to 50% by weight of metallic fuel, It also contains 15 to 20% by weight of terminal hydroxyl group polybutadiene (HTPB) as a binder and 35 to 40% by weight of ammonium perchlorate as an oxidizing agent.

<Problems to be Solved by the Invention> However, even the solid gas generating agent for the conventional ducted rocket engine as described above contains 35 to 40% by weight of the oxidizer, so that the metal fuel or the fuel / binder in the primary fuel chamber The binder is partially oxidized, and it is difficult to generate a gas rich in fuel components, and the combustion rate is slow, so the amount of gas generated is small, and the pressure index is low, changing the nozzle throat area of the primary combustion chamber. There is also a problem that it is difficult to control the gas flow rate from the primary combustion chamber.

For example, when the nozzle throat area is reduced to 1/2, if the pressure index is 0.4, the gas flow rate from the nozzle increases only about 3.2 times, but if the pressure index is 0.7, the gas flow rate from the nozzle is about 10.1. Doubled. The drawing shows how the relationship between the rate of change of the nozzle throat area and the gas flow rate from the nozzle changes with the change of the pressure index.
A practically effective pressure index is preferably about 0.5 to 0.7.

The present inventors have conducted intensive studies in view of the drawbacks of conventional solid gas generating agents for ducted rocket engines, and as a result, ethylene oxide and propylene oxide or propylene oxide in the main chain of the terminal hydroxyl group aliphatic polyether having an azidomethyl group in the side chain. A gas generating agent containing a specific amount of a polyether obtained by addition-polymerizing a specific amount of any of them, even if it does not contain an oxidant, stably combusts, generates a gas rich in fuel components, and has high combustion. The present invention has been completed based on the knowledge that the characteristics are speed and high pressure index.

<Means for Solving the Problems> The present invention has the general formula (In the formula, n represents 10 to 50 and m + 1 represents 1 to 10.) A ducted rocket engine characterized by containing 80 to 95% by weight of a terminal hydroxyl group aliphatic polyether having an azidomethyl group in its side chain. It is a solid gas generator for use.

In the present invention, a curing agent, a crosslinking agent, a curing catalyst and the like are included in addition to the polyether.

In the polyether represented by the above general formula used in the present invention, when the value of n exceeds 50, the viscosity becomes high and the productivity becomes poor. On the other hand, when the value of n is less than 10, the physical properties of the solid gas generating agent deteriorate.

Preferably, n = 20 to 50. Also, m + 1 is 10
If it exceeds, the burning rate of the gas generating agent will decrease. Preferably, m + 1 is in the range of n × 0.2 or less. The content of this polyether is 80 to 95% by weight. Preferably,
85-95% by weight. If it is less than 80% by weight, the burning rate is lowered, and if it exceeds 95% by weight, the physical properties of the solid gas generating agent are lowered.

The curing agent used in the present invention is, for example, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), polycyclic isocyanate compound such as tolylene diisocyanate and polyisocyanate compound such as polymethylene polyphenyl polyisocyanate compound, Preferred is HDI.

Examples of the cross-linking agent used in the present invention include trimethylolpropane (TMP) and trifunctional or higher functional polyols such as polyether triol and polyester triol. Preferred is TMP or a trifunctional polyol having a molecular weight of 1000 or less.

Examples of the curing catalyst used in the present invention include organic tin compounds such as dibutyltin dilaurate (DBTDL) and dibutyltin (2-ethylhexoate), organic bismuth compounds such as triphenylbismuth, and amines such as triethylenediamine. DBTD, which has a high catalytic effect
L or triphenylbismuth, which has a long pot life and can shorten the curing time, is preferable.

The proportion of the above additives is generally 5 to 20% by weight of the curing agent,
The crosslinking agent is 0 to 5% by weight, and the curing catalyst is 0 to 0.01% by weight.

In addition to the above additives, ammonium perchlorate (AP), triaminoguanidine nitrate (TAG
N), cyclotetramethylene tetranitramine (HMX),
Oxidizing agents such as cyclotrimethylenetrinitramine (RDX) and 1,2,4-butanetriol trinitrate (BTT
N), trimethylolethane trinitrate (TMETN)
Nitroplasticizers such as aluminum, magnesium, alloys thereof, and combustion improvers such as boron can also be included.

Next, a method for producing the polyether represented by the above general formula to be contained in the solid gas generating agent of the present invention will be exemplified.

That is, ethylene glycol, propylene glycol, α
-A reaction catalyst is dissolved in diols composed of monochlorohydrin and polymers thereof, and epichlorohydrin and ethylene oxide or propylene oxide or epichlorohydrin, ethylene oxide and propylene oxide are subjected to an addition reaction in the system to cause chloromethyl in the side chain. Producing a terminal hydroxyl group aliphatic polyether having a group,
The polyether and sodium azide are then reacted in dimethylformamide (DMF). The obtained polyether was confirmed to have the structure represented by the above general formula by elemental analysis, infrared absorption analysis, molecular weight measurement, hydroxyl value measurement and the like.

The solid gas generating agent for a ducted rocket engine of the present invention is obtained by, for example, adding a crosslinking agent, a curing catalyst, and then a curing agent to the polyether represented by the general formula and mixing them in a vacuum, and casting the mixture into a molding container. It is manufactured by heating and curing for a predetermined time.

<Effects of the Invention> The solid gas generating agent for a ducted rocket engine of the present invention has the characteristics of having self-sustaining combustibility by containing a specific polyether and capable of generating a gas having a large amount of fuel components. Furthermore, having a high burning rate and a high pressure index facilitates control of the gas generation rate, and has features that facilitate thrust control of a ducted rocket engine. As for the shape of the solid gas generating agent, it is possible to design the grains according to the end face combustion, the inner face combustion, and other purposes.

In addition, when it does not contain a combustion improver such as a metal fuel, it has a feature of being smokeless.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 A terminal hydroxyl group aliphatic polyether having a methyl azide group in the side chain represented by the above general formula (provided that n = 25, m = 1,
1 = 0) 84.82 parts by weight of trimethylolpropane (TMP) 3.18 parts by weight as a cross-linking agent and 0.01 parts by weight of dibutyltin dilaurate (DBTDL) as a curing catalyst are added, and the mixture is heated to 60 ° C. and vacuum mixed for 30 minutes. It was Then add hexamethylene diisocyanate (HDI) as a curing agent to this mixture.
11.99 parts by weight of was added and further mixed for 10 minutes under vacuum to obtain a liquid mixture. Then, this liquid mixture was cast in a predetermined molding container under vacuum, and after defoaming, curing at 60 ° C for 7 days
Solid gas generating agents for ducted rocket engines having the compositions shown in Table 1 were obtained.

A combustion test and a physical property test were performed by the following methods using the obtained gas generating agent.

(Combustion test) The gas generating agent was processed into a rod-shaped sample of 7 mm x 7 mm x 130 mm, and a melamine resin was applied to the surface thereof to form a strand piece. Nitrogen gas pressure of 10-70 Kgf / cm ^{2 was} applied to this strand piece using a Crawford type strand tester.
It was burned under and the burning rate was measured. Next, the pressure index was calculated from the relationship between the pressure and the burning rate.

(Physical property test) JIS K6301 (vulcanized rubber physical test method)
A sample was prepared based on the above, and the tensile properties were measured under the following conditions.

Test piece: No. 3 dumbbell Tensile speed: 100 mm / min Measuring temperature: 20 ° C Table 1 shows the burning speed, pressure index, tensile strength and elongation measured or calculated in the test above.

Examples 2 to 10 According to Example 1, gas generating agents having the compositions shown in Examples 1 to 10 in Table 1 were produced.

A combustion test and a physical property test were performed for each gas generating agent in the same manner as in Example 1.

The test results of each are shown in Table 1.

Comparative Example 1 A gas generating agent having a composition shown in Table 2 was produced in the same manner as in Example 1 except that the terminal hydroxyl group polybutadiene (HTPB) was used instead of the polyether used in Example 1.

Using this gas generating agent, a combustion test and a physical property test were conducted in the same manner as in Example 1.

The test results are shown in Table 2.

Comparative Examples 2 to 6 The gas generating agents shown in 2 to 5 of Table 2 were produced according to Example 1.

A combustion test and a physical property test were performed for each gas generating agent in the same manner as in Example 1.

The results of each test are shown in Table 2.

Examples 1 to 6 are solid gas generating agents of the present invention in which the binder serving as a fuel and a binder is composed of a terminal hydroxyl group aliphatic polyether having an azidomethyl group in the side chain represented by the above-mentioned general formula. It is apparent that these examples have self-sustaining combustibility when compared with Comparative Example 1 which is a solid gas generating agent in which the fuel / binder is only a terminal hydroxyl group polybutadiene (HTPB). Comparative Example 2 is a composition used for a composite propellant. Comparing the combustion performances of Comparative Example 2 and Comparative Example 4 with those of the Examples, the content of the polyether is
When it is 80% by weight or more (Example), the burning rate remarkably increases,
Moreover, it is clear that the pressure index also increases and has the characteristics of high burning rate and high pressure index.

Also, comparing the physical properties, the content of the polyether is 95
In Comparative Example 5 in which the weight percentage exceeds 100%, the stress (σ10
0) is significantly lower than that of the example. Further, in Comparative Example 3 using a polyether in which n is greater than 50 and Comparative Example 6 using a polyether in which n is less than 10, similarly, σ100 is lower than in the Examples and the physical properties are also lower.

Examples 7 to 10 are solid gas generating agents containing a small amount of an oxidizer or a metal fuel in addition to the fuel / binder, and all have characteristics of high burning rate and high pressure index.

[Brief description of drawings]

The drawing is a diagram showing the relationship between the rate of change in the nozzle throat area and the rate of increase in the gas flow rate from the nozzle at each pressure index.

Claims (1)

[Claims] 1. A general formula, (Wherein n represents 10 to 50, m + 1 represents 1 to 10), and 80 to 95% by weight of a terminal hydroxyl group aliphatic polyether having an azidomethyl group in the side chain is contained in the ducted rocket engine. Solid gas generating agent.