Formulation of a next-generation interior ballistic code

Two-phase flow interior ballistic codes, both one-dimensional and two-dimensional, have been developed over the last 20 years for the purpose of modeling the behavior of solid propellant gun propulsion systems. These codes have proven useful for explaining charge malfunctions and for studying possible remedies. Over the years, these codes have become increasingly elaborate as more complex designs have been addressed and also as the depth of simulation has increased. However, charge designs involving liquid propellant or electrothermal-chemical propulsion remain largely outside the scope of the solid propellant codes and a number of separate codes have been developed for the simulation of these alternative propulsion schemes. As we look to the future, it is evident that the next generation of interior ballistic models will be required to address three-dimensional details of the flow inside the gun. Such models will be expensive to develop and it is, therefore, of great interest to assess the extent to which a single code can be formulated to treat all foreseeable propulsion schemes. In this report, we review the physical problems of current interest, as well as those anticipated in the foreseeable future. We review the models currently available to address these processes. We then discuss the architecture, of a possible next-generation code. This discussion addresses the formulation of the equations, the choice of solution algorithms, and the implications of the current trend toward massively parallel computing.