Granulated Propellant Research Articles

Analysis and computation of three-dimensional, transient flow and combustion through granulated propellants

Gas-permeable solid propellants possess great potential for producing high thrusts during extremely short time intervals. This paper presents the theoretical formulation and application of a model describing the important physical phenomena taking place in both gaseous and solid phases in such three-dimensional, two-phase, unsteady, reactive flow systems, as found in internal ballistics. A stable, fast-converging, fully-implicit numerical method, was used to solve the coupled, non-linear differential equations of the model, so that effects of importance to the internal-ballistics designer can be studied. Solutions are presented that predict the pressure-wave build-up and accelerating flame-front for beds of granulated solid propellants in gun barrels with an accelerating projectile. The results show that the flame-front accelerates and the rate of pressurisation increases substantially in the downstream direction, as expected, and are physically reasonable in every respect.

A separated two-phase flow analysis to study deflagration-to-detonation transition (DDT) in granulated propellant

A two-phase reactive flow model is derived and solutions are applied to the analysis of the unsteady convective heat transfer in initially packed beds of granulated solid propellant or explosives. The resulting pressure wave and flame spreading event is considered the physical process that may provide for, deflagration-to-detonation transition (DDT) in such granulated beds. Discussions are included as to the appropriate constitutive laws required to complete the hydrodynamic model. The paper concludes with a brief assessment regarding both the limitations of the model and another possible DDT mechanism.