Determination of Flow Parameters in Double-Base and Modified Double-Base Propellants Using Squeeze Flow Rheometery

In this study, the rheological parameters such as yield stress, viscosity coefficient, and power law index were obtained for double-base propellants and modified double-base propellants formulations using the Squeeze flow rheometric method. Squeeze flow test was used to investigate the rheological behavior without wall slip condition, and to determine the temperature dependency of fluidity in double-base propellants and modified double-base propellants formulations. The results showed that for double-base propellants and modified double-base propellants formulations, the initial elastic behavior is identical in terms of phenomenology, however, differs in term of the value. There are distinct structural differences and different rheological properties between double-base propellants and modified double-base propellants formulations. By increasing the percentage of energetics nitramines (RDX) in modified double-base, the average squeeze flow force moves to higher values. A similar behavior is observed by decreasing the percentage of nitroglycerin. The results show that the Sherwood’s model for the flow of double-base propellants is better than the curves of modified double-base propellants, which reflects the deviation of the rheological behavior of modified double-base propellants from Herschel-Bulkley fluids.