JPS6012317B2 - Solid propellant type high performance ram rocket fuel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention produces a high-temperature fuel component by stably igniting and burning in the primary rocket engine outside, leaving almost no combustion slag, and in a ramjet combustion chamber. This invention relates to fuel for solid propellant ram rockets that generates extremely high specific impulse by spontaneously re-igniting when mixed with air.

A ram rocket is propelled as a ram rocket by incompletely burning a propellant or propellant designed with significantly more fuel than a normal rocket in the primary rocket motor, mixing the product with the air that is taken into the flying body, and re-igniting it. It is a type of combined engine of a rocket and a ramjet that generates energy, and is called an air-breathing rocket, rocket ramjet, or tacted.

However, if a primary rocket motor uses a propellant or a solid propellant with an overengineered fuel component as a propellant in order to generate the product that becomes the fuel for a ramjet, the motor uses normal liquid fuel. When combined with a ramjet, the fuel tank, fuel pump, and primary rocket nozzle will also serve as fuel injection valves, and the incomplete combustion products of the primary rocket, which are emitted at high temperatures, will become the pilot flame for ramjet combustion. Therefore, a ram rocket has an extremely simple structure, and because it uses air as an oxidizer, it can be said to be a high-performance propulsion engine that exhibits a significantly higher specific impulse than a normal rocket.

In solid propellant type ram rocket fuel, metal fuels with a high calorific value are usually used to generate high specific impulse, but these metal fuels have already been used in ordinary high performance solid propellants and have safety and safety issues. Aluminum is superior in terms of reliability and has a calorific value per volume that is more than twice that of ordinary hydrocarbons due to its high specific gravity.Although it is inferior to aluminum in terms of safety and calorific value, it has excellent ignitability and combustion reaction. Magnesium, which has excellent properties, is used, as well as magnesium, which is an alloy that takes advantage of the characteristics of both metals, and boron, which has a significantly high calorific value, each having its own characteristics.

However, mass propellant type rams contain these metals as the main fuel components.

To summarize the research results regarding fuel for rockets, (i) regardless of the type of these metals, even if they are contained up to about 50% in the fuel, remarkable combustibility in primary rockets is maintained. (ii) If the composition of the remaining fuel excluding metal fuel is such that the ratio of fuel/binder such as synthetic rubber to oxidizing agent such as ammonium perchlorate is 6:4 or more, self-sustaining combustion in the primary rocket motor is possible. Maintains sexuality.

(iii) When aluminum is used as the main fuel component, although its melting point is as low as approximately 66%, its boiling point is as high as approximately 20% and its combustion is normally only carried out at high temperatures above its boiling point. The molten aluminum remaining in the primary rocket motor cannot be used as fuel for the ramjet, and the molten aluminum and a small amount of alumina generated accumulate in the nozzle of the primary rocket, or The flaking causes the pressure in the primary rocket motor to become unstable, which in turn causes unstable fluctuations in thrust.In order to suppress this drawback of aluminum, the amount of aluminum added is 40%.
Therefore, a very high specific impulse cannot be expected.
GM Magnesium is excellent in terms of ignitability and reactivity, but on the other hand, it is extremely unstable in powder form and requires coping with a suitable synthetic resin for safety reasons.

However, even if the surface of a large amount of magnesium powder is completely coated with a certain amount of synthetic resin, the technology that can guarantee safety in manufacturing and handling is still incomplete, and furthermore, the calorific value of this material is not very high. Good results cannot be expected from adding magnesium alone to fuel. M Magnalium has a relatively low melting point of about 1100°C, including melting at about 480°C, which is lower than the melting point of aluminum (about 660°C) and magnesium (about 650qo), and has good ignitability.
As the reactive magnesium burns preferentially, the temperature of the primary rocket motor increases, promoting the thermal decomposition of synthetic rubber, synthetic resin, etc., and increasing the fluidity of the remaining molten aluminum. The discharge rate of fuel into the ramjet combustion chamber is increased, and the amount of combustion residue remaining in the primary rocket motor is significantly reduced, allowing the advantages of aluminum and magnesium to be utilized.

However, even in this case, addition of 50% or more causes aluminum to accumulate in the nozzle, and furthermore, due to the atomization, fluctuations in the combustion pressure of the primary lot motor are caused. For this reason, ``the limit for addition is 45% for stable operation.'' Next, ``Boron is often combined with aluminum or magnesium, and when used alone as the main fuel component of ram rocket fuel, its extremely high melting point ( 21770)
Because of its boiling point and boiling point (3650° C.), it is discharged into the ramjet combustion chamber as a powder without changing much in the primary rocket, making it difficult to reignite and burn it in the combustion chamber.

Also, boron oxide is produced from some of the boron that burns in the primary rocket motor, but boron oxide differs from the first two oxides in that it has a low melting point of about 450 qo. Some of the insufficiently thermally decomposed products, such as synthetic rubber and synthetic resin, become combustion residue in the primary rocket motor, and some of them accumulate and adhere to the nozzle of the same aircraft as the molten aluminum mentioned above. Or, the result of repeated brooding will result in changes in combustion pressure and thrust. Therefore, in order to achieve stable combustion, the maximum amount of boron added is about 40%. As described above, when metal fuels with a high calorific value are used alone for ram rockets, as the amount added is increased, only the disadvantages of each metal are emphasized, making it impossible to achieve the intended purpose.

However, as shown in the results for magnalium, the calorific value of magnesium alone, which is one of its components, is high, and there are safety issues as well. By doing so, these shortcomings are improved, good ignitability, reactivity is preserved, and the effect of increasing the temperature of the primary rocket motor is remarkable. The magnesium oxide produced by the ram jet is also discharged into the ramjet combustion chamber without significantly decreasing its temperature, thereby facilitating the re-ignition of the mixture of fuel and ram air discharged from the primary rocket motor.

In particular, boron has a molecular weight of 4. The calorific value per weight is 1.9 ton compared to ordinary hydrocarbons, and the calorific value per volume is about three times that of normal hydrocarbons.It has good handling and safety, and is extremely useful for high-performance ram rockets. A preferred metal fuel.

However, as described above, when used alone, its shortcomings and shortcomings are emphasized and it is difficult to achieve the desired performance. The present invention has been made in view of the above-mentioned circumstances, and a number of prototype fuels for solid propellant type ramjet, each containing metal fuel such as aluminum, magnesium, magnalium, boron, etc., as the main fuel components were produced as prototypes, and the combustion characteristics of each were compared and studied. This was realized as a result of many efforts, with metallic boron as the main fuel component, synthetic rubber or synthetic resin as an auxiliary fuel component and binder, and an oxidizing agent that has self-sustained combustion properties in the primary rocket motor. In the garden-type fuel for ram rockets, the solid fuel further comprises:
Provided is a solid propellant-type high-performance ram rocket fuel, which is composed by adding magsodium powder or magnesium powder, and is characterized by stabilizing ignition, ignition, and combustion in the primary rocket motor and ramjet combustion chamber, and improving combustion efficiency. For example, solid propellant type ram rocket fuel whose main fuel component is metallic boron powder with 5 to 25% magnalium added has a lower melting point due to the inclusion of magnalium, and magnesium is This results in preferential combustion, increasing the combustion temperature of the primary rocket motor, which in turn improves the main fuel emission rate, reduces fuel residue, and reduces unreacted boron discharged into the ram combustion chamber. The mixture of decomposition products of fuel/binder and ram air and re-ignition are reliably carried out by the magnesium oxide discharged at high temperature, and furthermore, it has a remarkable effect of stably sustaining combustion. It has many advantages.

The present invention will be explained below based on Examples.

Propellants containing metal fuel inevitably emit smoke because their exhaust contains particles of the oxide of the metal.

In the case of a ram rocket, although it is diluted by a large amount of air,
In the case of a fuel containing metal fuel as the main fuel component as in the present invention, the effect of the above-mentioned dilution cannot be expected much, and therefore it is not very meaningful to consider making the exhaust bonito-free. In this example, we chose ammonium perchlorate, which has excellent self-sustaining combustion performance, although it does produce smoke. In addition, the auxiliary fuel and binder is an important element that shares the mechanical strength of this fuel, but since the fuel according to the present invention essentially has an excess of fuel components, it is better than a normal propellant. It can be contained sufficiently. In this example, a synthetic rubber manufactured from HTPB (terminated hydroxyl group polybutadiene, manufactured by ARC○ Corporation in the United States, trade name: Poly-WR-45), which is used in high-performance solid propellants, is used. Table 1 shows the composition of the fuels tested and their combustion characteristics and combustion performance.

Rough ship fu* q Q Kuin'daihei＼ Kui, l Mito 4 Itoheto Kimi 9 no Ku Z ig l' 9 Kikanto R... Groove - 3 < Of these, compositions 1 to 6 For comparison purposes, compositions 7 to 9 are ram rocket fuels according to the present invention using conventional designs of aluminum, magnalium, and poron as the main fuel components, with concentrations of 20 and 10, respectively.
The main fuel component is boron containing 5% magnalium.

Claims (1)

[Claims] 1. A solid type for ram rockets, which contains metallic boron powder as the main fuel component, synthetic rubber or synthetic resin as an auxiliary fuel component and binder, and an oxidizing agent that maintains self-sustained combustion in the primary rocket motor. In the fuel, the above-mentioned solid fuel is constituted by adding magnalium powder or magnesium powder, which is an alloy of magnesium and aluminum, to the above-mentioned solid fuel to stabilize ignition, ignition, and combustion in the primary rocket motor and ramjet combustion chamber. A solid propellant-type high-performance ram rocket fuel that is characterized by improved efficiency.