Solid propellants: AP/HTPB composite propellants

A comprehensive theoretical/numerical model for treating AP/HTPB composite-propellant combustion in a rocket-motor environment is presented. The formulation takes into account the conservation equations in both the gas and condensed phases, and accommodates finite-rate chemical kinetics and variable thermophysical properties. The processes in the two phases are coupled at the surface to determine the propellant burning behavior. An asymptotic analysis based on a large activation-energy approximation for the condensed-phase decomposition is applied to help resolve the combustion wave structure in the interfacial layer. A simplified global reaction is employed to characterize the final diffusion flame between the decomposition products of AP and the pyrolysis products of HTPB. Only laminar flows are considered here, to avoid complications arising from turbulence. A detailed parametric study is conducted on the gas-phase flame structures of AP/HTPB composite propellants. The dependence of burning rate, flame...

http://www.yang.gatech.edu/publications/Journal/CST%20(2008,%20AP-HTPB,%20Cai).pdf

A Model of AP/HTPB Composite Propellant Combustion in Rocket-Motor Environments

In this review, an attempt to collect the summarised data of literature on catalytic effect of nano-oxides, such as mono oxides, mixed oxide, binary and ternary ferrites and rare earth metal oxides on the thermal decomposition of ammonium perchlorate (AP) is made. Influence of size effect of oxides on thermal decomposition of AP and comparison of bulk and nanosized oxides is also discussed here. Several experimental results revealed that due to small size and large surface area nanosized metal oxides are more potential catalysts on thermal decomposition of AP compared to their bulk size oxides.

https://www.tandfonline.com/doi/pdf/10.1080/17458080.2010.517571

Nano-metal oxide: potential catalyst on thermal decomposition of ammonium perchlorate

Thermal decomposition of ammonium perchlorate—A TGA–FTIR–MS study: Part I

Several transition metal complexes of triaminoguanidine (TAG) nitrate, TAG-Ni, TAG-Co, graphene oxide (GO)/TAG-Ni (GT-Ni), GO/TAG-Co (GT-Co), and GO/ TAG-Cu (GT-Cu) were prepared using GO as a stabilizer. It has been shown that these complexes are promising energetic catalysts for decomposition of ammonium perchlorate (AP), which was uniformly coated with the mentioned catalysts. The decomposition kinetic parameters and mechanisms of the complexes have been studied by means of differential scanning calorimetry/thermogravimetric techniques. Results show that the presence of GO in such hybrid catalysts is able to stabilize AP before its decomposition, but the strong catalytic effects occur on HClO4 as the intermediate of the initial decomposition of AP. In the cases of TAG-Co, GT-Co, and GT-Cu, they would make the two-step decomposition of AP into a single step. The heat releases have been greatly increased as well because of a more complete decomposition. More importantly, the thermolysis mechanism of AP c...

Thermal Behavior and Thermolysis Mechanisms of Ammonium Perchlorate under the Effects of Graphene Oxide-Doped Complexes of Triaminoguanidine

W ORLDWIDE, ammonium perchlorate (AP, NH^CIC^) and hydroxylterminated-polybutadiene (HTPB) composite mixtures, usually also containing aluminum powder and ballistic modifiers, are the most frequently used formulations in solid rocket propellants. In terms of publications, AP has been the most extensively investigated solid oxidizer since its introduction into propellants, probably in the late 1940s by the Jet Propulsion Laboratory. A large number of publications appeared in 1950-1970, and, by comparison, a relatively lesser number have appeared since then. The impressive review by Jacobs and Whitehead was quite extensive in range and depth at the time of publication in 1969. The falloff in research interest after this time is reflected in the additional information reviewed 10-15 years later, but subsequent reviews of various aspects of decomposition, ignition, and combustion" of AP-composite propellants have appeared. A modest resurgence of new interest in AP-composite propellant decomposition and combustion is motivated in part by the availability of advanced methods of diagnostics," by new kinetics data and methods of modeling," and by intriguing plateau-burning behavior of some AP-HTPB formulations.' Despite the widespread use and long investigative history of AP-fuel mixtures, it still can be said that AP alone and AP-fuel composites remain among the most confounding materials in the research setting. From the point of view of chemistry, one reason is that the full range of formal oxidation states of nitrogen and chlorine can apparently become involved, for example, the formal oxidation state of Cl in C1O4 is +7, whereas that of HC1 is -1; N in NHj is -3, whereas that of N in NOj (Ref. 19) and HNO3 (Ref. 20) is +5. When all of the various combinations of

T. B. Brill

Papers

Flash Pyrolysis of Ammonium Perchlorate-Hydroxyl-Terminated-Polybutadiene Mixtures Including Selected Additives