Место издания:SCIENCE PRESS MONMOUTH JUNCTION, NJ 08852-3014 USA
Первая страница:496
Последняя страница:505
Аннотация:Combustion on model propellant compositions prepared from hexanitrohexaazaisowurtzitane (CL-20) of either fine (20-50 mm) or coarse (250-450 mm) particles and glycidyl azide polymer (GAP) of low molecular weight (similar to 1000), or with polyurethane binder plasticized by nitroglycerine (NG/PU) has been studied. Both binders were capable of self-sustained burning with the rate less than that of CL-20 and showed low pressure exponents. The content of CL-20 in the compositions varied from 10% to 80%. The burning of the compositions has been shown to propagate through either binder layer between the particles or be subjected to the geometrical model, depending on the CL-20 particle size. A geometric combustion model for systems with fast-burning inclusions describes satisfactorily the combustion of compositions containing coarse particles at high pressures. The burning rate-pressure dependence for the compositions with coarse particles revealed a break, with the pressure exponent neared to that of the binder before the break and to that of the solid filler after the break. Substitution of the nitroglycerine-based binder by GAP had little effect on the ballistic parameters of the mixtures with coarse particles of CL-20. Mixtures of GAP with fine particles of CL-20 burned faster than analogous NG/PU-based mixtures at all pressures studied, even exceeding CL-20 at low pressures. A suggestion has been made that interaction between decomposition products of both GAP and CL-20 occurred, resulting in an increased temperature of the first flame and playing important part at low pressures. A phenomenological model for combustion of the binary compositions has been proposed to explain the observed burning peculiarities, based on different thermal behaviors of the ingredients.