DE1270459B - Semi-solid and solid rocket propellant - Google Patents

Description

FEDERAL REPUBLIC I) L ΪΠ SCHLAND

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C 06 d

German class: 78 d-1/01

Number: 1270 459

File number: P 12 70 459.5-45

Filing date: October 22, 1963

Opening day: June 12, 1968

The invention relates to semi-solid and solid rocket propellants, consisting of a homogeneous dispersion of a finely divided inorganic oxidizing agent, especially ammonium perchlorate, and solid aluminum in at least 20 "s and especially at least 30 "" of the total volume constituting organic fuel binders based on organic liquids or polyols. like nitrocellulose. Nitrocellulo: e-nitroglycene. Polyurethane, pol} vinyl chloride (with or without m Plasticizer additive / l.

Such fuel propellants produce after installation in the combustion chamber of a rocket engine and ignition of high temperature gases, which are used to produce the heart at high speed through the Exit the nozzle of the rocket gun.

The parameter that is generally characteristic of the propulsive power of a rocket propellant is considered is the specific impulse that iil :; Weight unit of the thrust is defined, which per Weight unit of the propellant charge per second is generated. Although this characteristic of the propellant charge as a Criterion for evaluating its performance is very important. however, the specific impulse is not that sole factor that applies to a specific application. when including the missile system as a whole its inert parts such as the weight of its motor housing and its payload must be taken into account, determines optimal performance.

Commonly used in rocket propulsion are the following Aims pursued:

1. Achieving a maximum in height and distance,

2. Achieving a minimum of the time needed ^{to reach the goal 3 s and}

Semi-solid and solid rocket propellant

3. Achieving maximum thrust.

Each of these goals is achieved by maximizing the takeoff thrust speed, which is given to the rocket by the combustion of the propellant. The start: clnibge:; speed is the speed of the rocket as it burns out minus its speed at launch.

It was found that the relationship between the starting thrust rate and dt η characteristics of the propellant charge that results from the application of the second Newtonian motion law :: elzes; h '! "rockets, for an idealized rocket that is free '.on the effect of gravity. Air pressure ν ir! smg and! »uicksiöüen isi.

Applicant:

Atlantic Pi - ea'cli Corporation,

Alexandria. Va. (V. Sl. A.J

Representative:

Dipl.-Ing. B. Longs?., Patent Attorney,

5100 Aachen, Augustastr. 14-16

Named as inventor:

Arch Chilton ScmlocK, Arlington. Va .;

Keith Ellis Rurnbel. Oakton, Va .;

Millard Lee Rice, Annandale, Va. (V. St. A.

is defined by the following equation:

In this formula means

1 U = starting thrust speed, i.e. Ii.

Burnout speed
minus the launch speed.

M ₁ = mass of the inert parts including the payload, i.e. mass of the rocket minus mass of the propellant,

V ₁ , = taken up by the propellant charge
Volume,

I _sp = specific momentum of the propellant charge,

L], = dimension conversion factor

9.65 kg mass · m / kg force · sec. ".
ο = density of the propellant,
WjFp = ratio of the rocket's inert parts to the volume of the propellant

From this equation of the relationships which determine the take-off thrust rate it can be concluded that two additional factors, namely the density of the propellant charge and the ratio of the inert parts to the propellant charge in the rocket module, are extraordinary w idüif. me! especially with high η values of Ai ₁ I _Γ ν ic ] \ n Fi> lk · of launch or auxiliary rockets. So a Treihsai / with a high specific impulse, but mii! ;; ei i * iehie for the Benul / unj '. in the presence of holi '.'i; Wcrien

so from Mjj \ ' _v because of a: ·; striking Ai (;>!; .- ai Si.n! - seluibgesclfv / mdh'l rilsvi irksamkei! au · -, e: s ^ relte ·! uii desired:., iii.

The specific momentum of the propellant charge is nevertheless an extremely important factor in determining the launch thrust of a rocket for any MJV _{p ratio.} A propellant charge which has a high specific impulse and at the same time generates an optimal take-off thrust speed with the presence of an optimal specific impulse is of great value for rocket technology, in particular in applications that require high propulsive power.

The invention has set itself the task of creating propellant charges which have a high specific impulse and generate maximum take-off thrust speeds over a wide range of the ratios of MJ V _p.

The subject of the invention is a semi-solid and solid rocket propellant consisting of a homogeneous dispersion of a finely divided inorganic oxidizing agent, especially ammonium perchlorate, and finely divided aluminum in an ^{organic fuel binder which makes up at least 20% and} especially at least 30% of the total volume based on organic liquids, for example the active oxygen of the inorganic oxidizing agent or an organic compound, such as a nitrate or nitrite derivative, causes an oxidation of the molecularly bound carbon in CO and the metallic fuel component in its oxide. Oxygen that is molecularly bonded to a carbon atom in an organic fuel compound, such as in the case of an ether, alcohol, aldehyde, ketone, ester, amide, etc., although it is not available for combustion, leads to a decomposition reaction as a result of a decomposition reaction Formation of CO, the desired propulsion gas product. In cases such as organic acids, in which the decomposition would normally lead to the formation of CO ₂ , one of the oxygen atoms combines preferentially with the metallic fuel component under the conditions specified for the desired oxidation ratio.

When the components are present in such a weight ratio that the specified number of oxidation ratios 0.5, what is hereinafter referred to as the "OMOx Formula" is that for the combustion of the fuel available sour

or polymers such as nitrocellulose, nitrocellulose - nitroglycerin - mixtures, polyurethane, 25 material stoichiometrically sufficient to remove the not yet polyvinyl chloride (with or without the addition of plasticizers), oxygen-bound carbon in the organider is characterized in that the quantitative ratio of inorganic oxidizing agent, aluminum and organic fuel binder of
formula

Molecular weights make the hydrogen gas a very effective thrust generating component of the combustion reaction product.

It has been found that propellants contain finely divided aluminum as a highly exothermic fuel component contain a maximum specific impulse and the missile system an optimal Grant take-off speed if that

see fuel to CO and the metal to oxidize to its oxide. Under such conditions, the molecularly bound hydrogen of the organic fuel compound forms free hydrogen gas after the ignition of the propellant, since the molecularly bound carbon and aluminum react preferentially with oxygen over O + C + M (-) hydrogen. That

\ ~ / evolved hydrogen gas is due to the high

= about 0.47 to 0.60 (oxidation ratio) and 35 corresponds to heat emission of the oxidized metal to a high, preferably about 0.47 to 0.55, with O heating temperature. This circumstance and its small amount of the total amount of bound oxygen, C the
Total amount of carbon and M the amount
of aluminum corresponds to O, C and M by the
Number of atomic equivalents are expressed and υ 4 °
corresponds to the value of aluminum.

Further features and advantages according to the invention emerge from the following detailed description and the drawings. Show in the drawings

F i g. 1 to 3 diagrams with a through the 45 ratio of oxygen to fuel (organic Starting thrust and the specific thrust and metallic fuel) of the formula OMOx the expressed comparison of the performance of driving equals or comes very close, d. i.e. if the Set that aluminum in various organic oxidation ratios about 0.47 to 0.60 and at Binders contain and many applications preferably about 0.47 to

F i g. 4 is a diagram with a comparison of 5 ° is 0.55. With such propellants he has Performance of several propellants different aluminum fuel the additional extremely beneficial Property that it forms a very stable oxide which, after its formation, does not appear in any decomposes or evaporates to a substantial degree, either under the high-temperature and high-pressure conditions, which are present in the combustion chamber while the combustion gases are still flowing out of the rocket nozzle. A decomposition and / or Evaporation of the metal oxide is undesirable in that it consumes substantial amounts of thermal energy Consume it, reducing the temperature and pressure of the thrust-generating combustion gases with low molecular weight is reduced. These findings are in the diagrams of the

specific impulse and different density at different ratios of the mass of the inert Parts of the rocket to the volume of the propellant. In the case of the reaction

C + 2Al + 4O = CO + Al ₂ O ₃ is the oxidation ratio number

⁴ = 0.5.

4 + 1 + 2 (^ -

All molecularly bound oxygen and with it
both that in the inorganic oxidizer and that in the organic fuel ⁶ 5 F i g. 1, 2 and 3 of the drawing by the material binding agent there is illustrated in the determination of the total summarized values. F i g. 1 shows the amount of oxygen taken into account. Oxygen, which is available for the curves for the specific impulse and the start of the oxidation reaction, such as the thrust speed of rocket propellants with aluminum

minium and ammonium perchlorate in a polyurethane fuel binder. This binder comprises a mixture of 56.6% prepolymer (polypropylene glycol, prepolymerized with an excess of tolylene diisocyanate, molecular weight 2025), 13.7% castor oil, 28.1% dioctyl acetate, 0.15% iron acetylacetonate, 1% lecithin and 0.7 % Phenyl- / i-naphthylamine. The F i g. Figures 2 and 3 show similar values of propellants, one using a double base binder consisting of nitrocellulose gelled with a mixture of nitroglycerin and dibutyl phthalate and the other using a binder comprising polyvinyl chloride plasticized with dioctyl adipate. All values were determined assuming a shift in the chemical equilibrium. The take-off thrust was determined at an M ,, F _p ratio of 960 kg / m- 'with the exception of Fig. 3, where this ratio was 400 kg'm ³ . It is noted that for all types of compositions the highest specific impulse and the highest take-off thrust rate were achieved within the oxidation ratio number range of 0.47 to 0.60, with a peak at or near an oxidation ratio number corresponding to the formula OMOx. Both the specific impulse and the take-off thrust speed are high. In the case of the composition with polyurethane, the maximum for the specific impulse is 260.2 kg sec./kg and for the starting thrust speed is 2589 m / sec. For the double base composition, the corresponding values are 262.4 kg sec / kg and 2655 m / sec, and for the composition with the plasticized polyvinyl chloride, the values are 258.4 kg sec / kg and 4230 m / sec.

It should also be noted that the curves for the maximum take-off thrust correspond very closely to those for the maximum specific impulse. This is a feature that is extremely beneficial because such propellants provide invariably high output over a wide range of MJV _p ratios.

In Fig. 4, the performance of a number of propellant charges is compared with a comparative propellant charge, specifically with regard to the propulsion of an idealized rocket, ie one in which the effects of downforce, gravity and pressure surges are neglected and in which a pressure prevailing in the combustion chamber is released by 70 kg'cm ² to 1.03 kg / cm ² takes place. It is noted that the aluminum-containing propellant has consistently high performance in terms of take-off thrust rate compared to that of the comparative propellant, while the very dense zirconium-containing propellant, although extremely effective at high M ₁ -V _p ratios, contributes to its performance low Μ _έ Τ _ρ ratios drops sharply and the low density propellant, which contains a mixture of liquid oxygen and hydrazine, although it performs well at low Mj Kp ratios, drops sharply in its take-off thrust performance when this ratio is high . Since the density (2.7) of aluminum is significantly higher than the density of the commonly used oxidation salts, such as NH ₄ ClO ₄ (1.95) and NH ₄ NO ₃ (1.73), the aluminum acts as a compression component within the propellant composition what, as in Fig. 4, is reflected in increased take-off thrust speeds ^{at high Mj 1} V ₁ , - ratios.

As already stated, the organic fuel binder can from any suitable organic compound or mixture of organic compounds exist that contain molecularly bound carbon and hydrogen, so that they are present a stoichiometry corresponding to the formula OMOx with formation of CO and free hydrogen gas burns and / or decomposes. The organic fuel binder can be inert. The expression "Inert" should mean that it is a compound that contains an external source of oxygen, namely the solid inorganic oxidizing agent, required for combustion. Examples of suitable organic binders are the various solid polymeric binders such as polyether, Polysulfides, polyurethanes, butadiene-acrylic acid and butadiene-acrylic methacrylic acid copolymers, the are crosslinked with an epoxy compound, alkyd polyesters, polyamides, cellulose esters, such as. B. cellulose acetate, Cellulose ethers, such as B. ethyl cellulose, polyvinyl chloride, asphalt and the like Such inert fuel binders are generated by the carbon-bound oxygen CO a decomposition reaction.

Many of the solid, polymeric binders preferably contain high-boiling, organic, liquid plasticizers, to improve the physical properties and processing of the propellant. Included Any of the numerous known plasticizers can be used with the propellant composition is compatible. Examples of suitable organic plasticizers are sebacates, such as Dibutyl sebacate and dioctyl sebacate; Phthalates such as dibutyl phthalate and dioctyl phthalate; Adipates, like Dioctyl adipates; Glycol esters of higher fatty acids and the like.

The organic fuel binder can also contain an active organic compound, a mixture of such compounds, or a mixture of such a compound with an inert organic compound such as an inert organic plasticizer. The term “active” compound is understood to mean a compound that contains molecularly bound oxygen that is available for the combustion of other components of the molecule such as carbon. Such active organic fuel compounds also include, for example, those containing nitroso, nitro, nitrite and nitrate residues, such as e.g. B. cellulose nitrate and nitroglycerin.
The foregoing description is primarily concerned with solid propellants in which the organic fuel binder is a solid. However, the invention can also be used in semi-solid, composite, monofuel systems. Such systems consist of thixotropic, cohesive and dimensionally stable compositions which, when moderate pressure is applied, can be forced into the combustion chamber of a rocket, where they then form continuously advancing columns which burn on their exposed surface. According to the invention, such plastic mono-propellants comprise a stable dispersion of a finely divided, insoluble oxidizing agent and the finely divided aluminum in one

7 8

continuous binders with any suitable standing compound that satisfies the formula OMOx

high boiling point. organic, liquid fuel, produced from lumber:

molecularly bound carbon and hydrogen percentages by weight

contains. Examples of suitable liquid fuel prepolymer *) 11,27

substances are hydrocarbons such as triethylbenzene. S castor oil 2.74

liquid polyisobutylene and the like; organic esters such as dioclylacelal 5,62

Dimethyl maleate. DibuHloxalate. Dibutyl phthalate and iron acetylacetonal 0.03

Nitroglycerin; Alcohols such as benzyl alcohol and tri-lecithin 0.20

ethylene glycol; Ethers, such as methyl -,) '- naphlhylether, phenyI -, / - naphthylamine 0.14

and many other connections. io aluminum powder 21.04

Any solid an- _{NH 4} ClO _{4 58.96}

organic oxidizing agents are used, the », Prcpolvmerisat: Polypropylene glycol, prepolymer with no additional oxygen for the combustion of an excess of Tolyiendiisocyanat; Molecular weight 2025. Provide the metallic fuel component and the organic binder, if the latter is not The driving salt was burned off statically in a rocket engine with oxygen or insufficient oxygen for the soil. Including the burning target of a stoichiometry with regard to CO. speed was 0.47 cm / sec. In the case of a combustible oxidizing agent, the inorganic chamber pressure of 79.1 kg'cm ² closes. oxidizing salts, such as perchlorates and nitrates of. . NH ₄ , K, Na and Li. Metal peroxides, such as CaO ₂ , 20 Example _ BaO ₂ and Na ₂ O ₂ and the like, but the salts A are solid. perforated, internally burning rake should be preferred. Drifting salt with a diameter of 15.25 cm and a

If the organic fuel binder mole weight was 4.5 kg from a mixture of

contains bound oxygen and these few- the following components are produced:

steep ·: is available in finer stoichiometric quantities, 25 pe «···]

the iVti (J "oxidation and / or decomposition of the mole- _Km " _In jca iti sp%

kul; u gilundenen carbon component to CO NIi ₄ L-IU ₄ .... -0./8

bcnöl ijil ν itd. aluminum powder is not an inorganic oxidizing agent. .. "Λ ~

required for your incineration. Are the ver Nitrocel ulose (12.6 ¹ ,,, N)

keeps Pissf · that in the organic fuel binding 30 (balls with a hook

min · 1 \ eipii! barcr bound oxygen in quantities _M ·? 1 · ™ "'7 YA' ", V Ve «oim

by and .. fsl. which is greater than for such a stoichio- Ni roglycerin-Dibutylphthakt 75 25 25.02

If they are egg-shaped, the excess, Lv ³ T u 1 '"·? m, oxidizes

The powdery metal 2-nitrodiphenylamine 1.00 is preferred for the amount of ice-cream

component instead of the molecularly bound 35 The propellant was processed according to the plastisol W, -.:; Sv'i: -t! IlK If necessary, the organic can be produced. In doing so, the components of Raum-Binimloif binders a part of the inorganic temperature mixed, the mixture then replace in an oxidizing agent, which is normally brought to the mold and there by heating from-Oxydatioii of the metal would be required. hardened to transform the nitrocellulose into the nitroglycerin,

The organic binder. 40 dibutyl phthalate and dibutyl sebacate plasticizers regardless of whether it is internal or active. solid or liquid is how to solve this. The composition corresponded to the formula described, must be at least about 20'V ₀ , in OMOx. The propellant burned in a Brennmanclteu traps preferably even at least 30 ¹ Vi), chamber pressure of 63 kg'cm ² with a Abbrenndes volume of the propellant charge account. This is a speed of 1.19 cm / sec. away. on the one hand essential to the generation of a 45 ...

suitable amount of combustion gas with little example.

Achieve molecular weight, which is necessary for an effective A fesler, perforated, internal burning rake

Propulsion is needed, and secondly it was propelled from a mixture of the following Significance for the manufacture of a together- components manufactured:

holding propellant, the good physical inherent 50 percent by weight

having shafts. _{NH C1Q 5g 9Q}

The amounts of aluminum and solid, inorganic-stabilized 'polyvinyl chloride''.'.'.'.'.'. ^ 96

Apparent oxidizing agents which are used Dioctvladinat 10 79

sen. must be such that the respective ^c ϊ P; '' -, Z _1n

organic binder has an oxidation ratio of 55

number results in that, in the specified range of. . _Dioctvln . _{l (riumsu} if _o .

0.47 to 0.60. Using the equation, dioleate dioctylinitumullo

for the determination of the oxidation ratio number ^{s cc} "'

The propellant was made according to the plastisol process

Woe be calculated. ^fl °, while its components were

The following examples explain the rocket propulsion temperature mixed, the mixture then in a mold si'i> r j -em according to the invention. poured and finally heated in this to the

Polyvinyl chloride in the liquid plasticizer too

Solve Example 1 to form a solid gel. the

^f) 5 oxidation ratio of the propellant charge corresponded

Lii: · fesler, perforated, internal burning poly of the formula OMOx. When burned down in a rocket fhan rocket propellant with a 15.25 cm diameter motor with a diameter of 12.7 cm burned υπ ?! A weight of 4.5 kg was converted from the propellant material per mil at a speed of 0.89 cm

Ss'fc. at a combustion chamber pressure of 77 kg / cm ² . The specific impulse measured was 242 kg Sefc./kg.

Claims (1)

Claim: Semi-solid and solid rocket propellant, consisting of a homogeneous dispersion of a finely divided inorganic oxidizing agent, especially ammonium perchlorate, and finely divided Aluminum in at least 20% and especially at least 30% of the total volume organic fuel binders based on organic liquids or Polymers such as nitrocellulose, nitrocellulose-nitroglycerin mixtures, Polyurethane, polyvinyl chloride (with or without added plasticizers), thereby characterized in that the quantitative ratio of inorganic oxidizing agent, Aluminum and organic fuel binder of the formula = about 0.47 to 0.60 (oxidation ratio) and preferably about 0.47 to 0.55, where O corresponds to the total amount of bound oxygen, C corresponds to the total amount of carbon and M corresponds to the amount of aluminum, O, C and M. are expressed by the number of atomic equivalents and ν corresponds to the valence of aluminum. Considered publications:
U.S. Patent No. 3094444. For this purpose 2 sheets of drawings 805 S59 / 136 5.68 © Bundesdruckerei Berlin