مدل سازی و راهکار عملی کاهش مهاجرت نیتروگلیسیرین (NG)در پیشرانه‌های جامد دوپایه

Double base propellant consists of two main components, nitrocellulose and nitroglycerin and nitroglycerin migration from inter to surface of propellant, is the main problem of this type of propellants. In the effect of this undesirable phenomenon, due to the heterogeneity of nitroglycerin in the propellant matrix during Storage, in addition to decrease of safety, the ballistic properties will be deeply changed. So, providing a model for predicting migration during storage and also practical solutions in decreasing of nitroglycerine migration is one of the favorite subjects for propellant specialists. In modeling of migration, penetration coefficient values, diagrams of amount of migrated nitroglycerin versus time, and dispersion of penetration on depth and surface of insulation and the migrated mass at balance time could be determined using the penetration phenomenon equations. One of the ways to decrease migration, is using of modified insulation based on mineral unsaturated polyesters contain mineral fillers. To this aim, in this work, at the first, several unsaturated polyester insulation in the presence of mineral filler synthesis and the influence of nitroglycerin on them was modeled by immersion test and the diffusion coefficients were calculated. The results showed that the modified unsaturated polyester insulation has a penetration coefficient of 1.027×10-4 cm2/s that in the presence of alumina three hydrates as the mineral filler, the penetration coefficient decreased to 6.777×10-6 cm2/s. Also the relative migrated mass at the infinitive time to the mentioned insulation was 6.4622 and it is decreased to 2.469 in the presence of mineral filler. So, presence of filler in the insulation matrix, could be significantly decreased the penetration of nitroglycerin, whereby the safety and the lifetime of propellant will increase.