| || Size and Shape of Ammonium Perchlorate and their Influence on Properties of Composite Propellant
Author : Jain, Sunil ;Mehilal;Nandagopal, S. ;Singh, P.P. ;Radhakrishnan, K.K. ;Bhattacharya, B.
Source : Defence Science Journal ; Vol:59(3) ; 2009 ; pp 294-299
Subject : 54 Chemistry;620.261 Explosives;662.3 Propellants
Keywords : Ammonium perchlorate;Average particle size;Particle shape;Composite propellant;Shape factor
Abstract : Most of the composite propellant compositions contain solid loading up to 86 per cent. The main solid ingredients of composite propellant are ammonium perchlorate (AP) and aluminium powder. Therefore, it is a must to characterise these to improve processibility and quality of composite propellant. Effect of particle size on propellants slurry viscosity and ballistic parameters are well documented, however, the effect of oxidizer particle shape is not reported. In the present study, different methods for size and shape characterization are discussed and effect of size and shape of AP on composite propellant properties are studied. The data indicate that as size of AP decreases, propellant slurry viscosity increases and burn rate increases. The particles having higher shape factor provides less endof mix (EOM) viscosity of propellant slurry and burn rate. Further, effect of size of ground AP on shape is also investigated. From the data thus obtained, it is inferred that as size of ground AP decreases, shape factor decreases, and particles become more irregular in shape.
| || Prediction of Particle Size of Ammonium Perchlorate during Pulverisation
Author : Jain, Sunil;Mulay, M.P.;Mehilal;Singh, P.P.;Bhattacharya, B.
Source : Defence Science Journal ; Vol:56(3) ; 2006 ; pp 423-431
Subject : 662.3 Propellants
Keywords : Ammonium perchlorate;Grinding;Air classifier mill;Composite propellant;Average particle size;Modelling equation;Burn rate
Abstract : Ammonium perchlorate has been pulverised by an impact mill (air classifier mill) to study the influence of different operating parameters, viz., effect of mill speed, classifier speed, feed rate, and damper opening (suction rate) on the particle size. Further based on the different grinding parameters, an empirical equation has been developed and used for the prediction of particle size. The experimental results indicate that the values are very close to the predicted ones. In addition, particle size distribution has also been studied by applying different model equations and it has been found that Rosin-Rammler model is the most suitable model for this operation.