Propellants applications

The effect of nucleating sources is important when attempting to scale studies with models tO full-size components. A common practice in model tests is to expose the fluid to a high static pressure prior to testing in order to drive free gas into solution. In contrast the seeding of water tunnels is considered to improve scaling particularly in high-speed propeller applications . 

Refs 1) Beil — DADNBU not found DADNPE not found 2) LP. Kuhn A.C. Duckworth, The Preparation of Some New Polyfunctional Organic Azides , BRL Rept No 1607 (1972) also, the following limited distribution Addnl Ref YP. Carignan, Evaluation of Some New Poly functional Organic Azides for Propellant Applications , PATR 4592(1973)... 

The EPA outlawed CFC-11 and -12 in aerosol and propellant applications because of fear of ozone depletion. They were replaced by propane and butane, highly flammable hydrocarbons. 

The urethane reaction is particularly useful for solid propellant applications because of its quantitative nature, convenient rate which can be adjusted by proper choice of catalysts, and the availability of many suitable hydroxyl compounds which permit the tailoring of propellant mechanical properties. Despite the quantitative nature and apparent simplicity of the urethane reaction R NCO + ROH - R NHCOOR, its exact course has not been fully explored yet. It does not follow simple second-order kinetics as the above formula would suggest since its second-order rate constant depends on many factors, such as concentration of reactants and the nature of the solvent. Baker and co-workers (2) proposed that the reaction is initiated through the attack of an alkoxide ion on the carbon atom of the isocyanate group... 

To establish the relationship between current liquid propellant applications and the available propellant technology, this paper has been divided into three sections. A section on basic propellant considerations describes the normal parameters used to evaluate propellant candidates and their influence on the propulsion system. Although such considerations have been thoroughly discussed in many previous publications (e.g., Ref. 3), their importance in establishing the basic criteria for propellant system selection requires a limited review in this text as a background aid to the reader. Current liquid propellants and propellant candidates are discussed in a second section in terms of capabilities and limitations as well as potential application areas (the compositions of all propellants discussed are defined in the Nomenclature section at the end of this article). Finally, a section of propellant tailoring illustrates examples of propellant formulation and describes propellant problem-solving techniques. In conclusion, the results of these considerations are illustrated by the current liquid propellant systems. 

Upper stage propellant applications are usually based primarily on performance—i.e., high specific impulse. If the upper stage is a multistart vehicle, hypergolicity is usually required. Careful consideration is also given to the propellant physical and chemical stability as well as to the matching of the propellant s liquidus range to the space environmental temperature if the propellant system is to remain operational in space... 

Homogeneous Liquids. The physical properties important in determining the suitability of a liquid for propellant application are the freezing point, vapor pressure, density, and viscosity. To a lesser extent, other physical properties are important such as the critical temperature and pressure, thermal conductivity, ability to dissolve nitrogen or helium (since gas pressurization is frequently used to expel propellants) and electrical conductivity. Also required are certain thermodynamic properties such as the heat of formation and the heat capacity of the material. The heat of formation is required for performing theoretical calculations on the candidate, and the heat capacity is desired for calculations related to regenerative cooling needs. 

These compounds exhibit very low pressure-dependence during combustion and the compound [3,6-bis(nitroguanyl)-l,2,4,5-tetrazine] in particular, shows the lowest pressure exponent known in the literature for a neat material. Further, the interesting combustion behavior of these explosives make them suitable for gasgenerating and propellant applications [288]. 

Pak, Z.P. (1993) Some ways to higher environmental safety of solid rocket propellant application. AIAA Paper 93-1755. 

This material has been considered as a potential candidate for high-energy propellant applications. A yellow form may be obtained from ethanol, while a pale-orange modification crystallizes from acetone. They crystallize in (equivalent) F2i/c and P2i I a space groups respectively, both with Z = 0.5, requiring that the molecule lies on a crystallographic inversion centre and exhibits an essentially planar molecular conformation (Cromer et al. 1988). 

Although these nitroimidazole derivatives were studied mainly for their pharmacological medicinal chemistry, they were seldom studied for their use in explosives and propellants application. However more recently these nitroimidazoles, as so-called high energy density materials , have attracted renewed attention due to their favorable detonation performances. 

B High purity industrial, fuel, and propellant applications... 

Primer (a common version is the percussion primer) A term for the device used to ignite smokeless powder in small arms ammunition or other propellant applications. An impact-sensitive composition is typically used. When struck by a metal firing pin, a primer emits a burst of flame and hot particulates capable of rapidly igniting the propellant charge. Several typical primer mixtures are given in Table 7.2. 

Whistle compositions were initially developed in the search for possible replacements for black powder in propellant applications. One can imagine the reaction of the first pyrotechnic chemist who blended what is now known to be a whistle composition in a research setting, pressed the powder into a tube to examine its propellant characteristics, and then heard a loud, piercing screech when the composition was ignited. 

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