Modelling Gun Interior Ballistics

This report presents an overview of the models and numerical techniques available to handle propellant combustion and the induced projectile motion within a gun barrel. Included in the report are reviews of multi{phase modelling approaches that can be employed to capture the dynamics of the propellant{gas mixture in the barrel, together with a discussion of numerical methods suitable for representing the evolving geometry of individual propellant grains. Potential approaches for the detailed modelling of the chemical kinetics of nitro- esters, commonly found in gun propellants, are also reviewed. Finally, the motion of the projectile within the gun-barrel is considered, and techniques for solving the resultant moving-boundary problem are discussed. Initial simulation results are presented from numerical ow solvers based on the open{source OpenFOAM toolbox. The test case used for these simulations is that of a Bofors 40mm m/70B gun chamber. These results demonstrate the potential of such solvers for elucidating the ow physics, but also illustrate the need for further development of the CFD model and solver. Additionally, a summary is provided of the gun barrels available for potential use in an experimental campaign to support the validation of the modelling work.